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  • 1.
    Alevanau, Aliaksandr
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Study of the Apparent Kinetics of Biomass Gasification Using High-Temperature Steam2010Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Among the latest achievements in gasification technology, one may list the development of a method to preheat gasification agents using switched ceramic honey combs. The best output from this technology is achieved with use of water steam as a gasification agent, which is heated up to 1600 °C. The application of these temperatures with steam as a gasification agent provides a cleaner syngas (no nitrogen from air, cracked tars) and the ash melts into easily utilised glass-like sludge. High hydrogen content in output gas is also favourable for end-user applications.Among the other advantages of this technology is the presumable application of fixed-bed-type reactors fed by separately produced and preheated steam. This construction assumes relatively high steam flow rates to deliver the heat needed for endothermic reactions involving biomass. The biomass is to be heated uniformly and evenly in the volume of the whole reactor, providing easier and simpler control and operation in comparison to other types of reactors. To provide potential constructors and exploiters of these reactors with the kinetic data needed for the calculations of vital parameters for both reactor construction and exploitation, basic experimental research of high-temperature steam gasification of four types of industrially produced biomass has been conducted.Kinetic data have been obtained for straw and wood pellets, wood-chip charcoal and compressed charcoal of mixed origin. Experiments were conducted using two experimental facilities at the Energy and Furnace Division of the Department of Material Science and Engineering (MSE) at the School of Industrial Engineering and Management (ITM) of the Royal Institute of Technology (KTH) and at the Combustion Laboratory of the Mechanical Engineering Department of the University of Maryland (UMD), USA.

    The experimental facility at the Energy and Furnace Division has been improved with the addition of several constructive elements, providing better possibilities for thermo-gravimetric measurements.The obtained thermo-gravimetric data were analysed and approximated using several models described in the literature. In addition, appropriate software based on the Scilab package was developed. The implementation of the isothermal method based on optimisation algorithms has been developed and tested on the data obtained under the conditions of a slow decrease of temperature in experiments with the char gasification in small-scale experimental facilities in the Energy and Furnace Division.The composition of the gases generated during the gasification of straw and wood pellets by high-temperature steam has been recorded and analysed for different experimental conditions.

     

  • 2.
    Alevanau, Aliaksandr
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Ahmed, Islam
    Gupta, Ashwani K.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Parameters of high temperature steam gasification of original and pulverised wood pellets2011In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 92, no 10, p. 2068-2074Article in journal (Refereed)
    Abstract [en]

    Experiments on gasification of chars obtained from original and pulverised wood pellets were conducted in atmosphere of water steam and nitrogen under temperatures of 800, 900 and 950 degrees C. Molar flow rates of carbon containing product gases were measured and approximated using different models with respect to extents of carbon conversion in char of the pellets. Comparison of the random pore, grain and volumetric models revealed the best applicability for approximations of the random pore model. Apparent activation energies obtained as a result of application of the models to the data from experiments with char of original pellets were higher in comparison to those of pulverised pellets, except for a grain model. Approximations under 800 degrees C showed relatively big deviations from experimental data on the beginning of char gasification. This is attributed to catalytic effects from alkali metals in the pellets.

  • 3.
    Alevanau, Aliaksandr
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Donaj, Pawel
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Applicability of Scaling Approach for Analysis of Pyrolysis and Gasification of Porous Structures Composed of Solid Fuel Particles2012In: ISRN Mechanical Engineering, ISSN 2090-5122, E-ISSN 2090-5130, article id 207464Article in journal (Refereed)
    Abstract [en]

    Experimental research on the pyrolysis and gasification of randomly packed straw pellets was conducted with an emphasis on the reactive properties of the shrinking porous structure of the pellets. The apparent kinetics of such pyrolysis was approximated by the random pore, grain, and volumetric models. The best approximation results were obtained with the grain and random pore models. The self-organized oscillations of the pellet conversion rate during pyrolysis were observed. Two complementary explanations of the phenomenon are proposed.

  • 4.
    Alevanau, Aliaksandr
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Donaj, Pawel
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    High temperature steam gasification of straw pelletsManuscript (preprint) (Other academic)
  • 5.
    Alevanau, Aliaksandr
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Ersson, Mikael
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kuznechik, Olgerd
    Belarussian State University.
    Vyhoniailo, Oleksandr
    Mechanically assisted low temperature pyrolysis of hydrocarbons2014In: Proceedings of the XVII International Conference Foundations & Advances in Nonlinear Science, September 29 - October 3, Minsk 2014, 2014Conference paper (Refereed)
    Abstract [en]

    We report experimental setups and conditions leading to pyrolysis (cracking) of such gaseous hydrocarbons as methane, mixed propane and butane, at the temper-atures of the heater below 200oC. The process was mechanically assisted by putting the substances being decomposed into a dynamic interaction with the tin and bismuth alloy. The alloy had periodically changing phase state thus creating fractal interfaces between its surface and the gases. Interaction of the gases with mechanically produced fractal surfaces of the alloy made possible gas decomposition even at lower temperatures of the heater (150oC). At this temperature the heater couldn't melt the alloy in the heated volume with the gas.

  • 6.
    Alevanau, Aliaksandr
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Study of the effects of gaseous micro-expansion on the efficiency of convective heat transfer during pyrolysis2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 106, p. 253-261Article in journal (Refereed)
    Abstract [en]

    Measurements of temperature in the proximity of wood pellets (8 mm diameter) and thin wooden stick slices (5 cm diameter and 5 mm thickness) were conducted to estimate the effects of mixing between the evolving volatiles and hot steam (T > 700°C) flowing around the particles. Measurements of mass loss of the slices were conducted to estimate the apparent kinetic parameters of their pyrolysis. A simple kinetic model of the process (type II by Pyle and Zaror (1984) [20]) was investigated. The experiments showed a plateau-like part in the graphs of temperature measured in the proximity to the samples. The existence of this plateau-like part agrees with the general data of calorimetric measurements of pyrolysis, which show extensive energy consumption in the beginning of an active production of volatiles. A hypothesis regarding feedback on the process due to the micro-expansion and mixing of volatiles in the convective boundary layer is discussed.

  • 7.
    Alevanau, Aliaksandr
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kuznechik, O.
    Vyhoniailo, O.
    Prospective side effects of the heat and mass transfers in micro-porous structure of char during intermediate and final stages of the high-temperature pyrolysis2013In: Nonlinear Phenomena in Complex Systems, ISSN 1561-4085, E-ISSN 1817-2458, Vol. 16, no 3, p. 287-301Article in journal (Refereed)
    Abstract [en]

    The general problem of a decrease of activation energy for reactions of thermal decomposition in ligno-cellulosic materials in the end of the high-temperature pyrolysis has been discussed. Experiments emphasizing the differences between the starting, intermediate and final stages of the process were conducted. A hypothesis to solve the problem from the point of view of a fundamental fractal theory was formulated. The conclusions of the discussions related to the hypothesis gave a description of new experiments to prove the fundamental theory on diffusion processes with naturally or artificially created conditions for self-organization.

  • 8. Aziz, M.
    et al.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Production of hydrogen from algae: Integrated gasification and chemical looping2017In: Proceedings of the 9th International Conference on Applied Energy, Elsevier, 2017, Vol. 142, p. 210-215Conference paper (Refereed)
    Abstract [en]

    Due to their high potential and beneficial characteristics, algae is considered as very promising energy source in future. In this study, an integrated conversion system of algae to hydrogen is proposed with the objective of high total energy conversion efficiency. The proposed system mainly covers algal drying, gasification, and chemical looping. To facilitate optimum heat circulation throughout the proposed system, enhanced process integration is adopted. It combines exergy recovery and process integration technologies in order to achieve a wasted energy, hence the total energy efficiency can be improved significantly. In the proposed system, to convert algae to hydrogen, steam gasification and syngas chemical looping are integrated as the main conversion. Iron oxide is employed as the oxygen carrier, and is circulated among the reactors in the chemical looping module. Process modeling and calculation is performed using ASPEN Plus, and the total energy efficiency, including hydrogen production and power generation, is evaluated. Several operating parameters including target moisture content in drying, steam-to-biomass ratio in gasification, and chemical looping pressure, are observed. From the results, it is shown that the proposed system is potential to convert algae to hydrogen with high total energy efficiency, which is higher than 70%. Both target moisture content and steam-to-biomass ratio influence strongly the total energy efficiency. On the other hand, chemical looping pressure show insignificant effect to total energy efficiency.

  • 9.
    Biswas, Amit Kumar
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Thermochemical behavior of pretreated biomass2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mankind has to provide a sustainable alternative to its energy related problems. Bioenergy is considered as one of the potential renewable energy resources and as a result bioenergy market is also expected to grow dramatically in future. However, logistic issues are of serious concern while considering biomass as an alternative to fossil fuel. It can be improved by introducing pretreated wood pellet.

    The main objective of this thesis is to address thermochemical behaviour of steam exploded pretreated biomass. Additionally, process aspects of torrefaction were also considered in this thesis. Steam explosion (SE) was performed in a laboratory scale reactor using Salix wood chips. Afterwards, fuel and thermochemical aspects of SE residue were investigated. It was found that Steam explosion pretreatment improved both fuel and pellet quality. Pyrolysis of SE residue reveals that alerted biomass composition significantly affects its pyrolysis behaviour. Contribution from depolymerized components (hemicellulose, cellulose and lignin) of biomass was observed explicitly during pyrolysis. When devolatilization experiment was performed on pellet produced from SE residue, effect of those altered components was observed. In summary, pretreated biomass fuel characteristics is significantly different in comparison with untreated biomass. On the other hand, Process efficiency of torrefaction was found to be governed by the choice of appropriate operating conditions and the type of biomass.

  • 10.
    Biswas, Amit Kumar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Umeki, Kentaro
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Change of pyrolysis characteristics and structure of woody biomass due to steam explosion pretreatment2011In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 92, no 10, p. 1849-1854Article in journal (Refereed)
    Abstract [en]

    Steam explosion (SE) pretreatment has been implemented for the production of wood pellet. This paper investigated changes in biomass structure due to implication of steam explosion process by its pyrolysis behavior/characteristics. Salix wood chip was treated by SE at different pretreatment conditions, and then pyrolysis characteristic was examined by thermogravimetric analyzer (TGA) at heating rate of 10 K/min. Both pyrolysis characteristics and structure of biomass were altered due to SE pretreatment. Hemicellulose decomposition region shifted to low temperature range due to the depolymerization caused by SE pretreatment. The peak intensities of cellulose decreased at mild pretreatment condition while they increased at severe conditions. Lignin reactivity also increased due to SE pretreatment. However, severe pretreatment condition resulted in reduction of lignin reactivity due to condensation and re-polymerization reaction. In summary, higher pretreatment temperature provided more active biomass compared with milder pretreatment conditions.

  • 11.
    Biswas, Amit Kumar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Umeki, Kentaro
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Change of pyrolysis characteristics to steam explosion pretreatment of biomass2011In: International conference on Applied Energy, 2011Conference paper (Refereed)
  • 12.
    Biswas, Amit Kumar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Devolatilization characteristics of steam explosion pretreated wood pelletIn: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188Article in journal (Other academic)
  • 13.
    Biswas, Amit Kumar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Steam pretreatment of Salix to upgrade biomass fuel for wood pellet production2011In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 92, no 9, p. 1711-1717Article in journal (Refereed)
    Abstract [en]

    Steam explosion (SE) pretreatment is served to separate the main components of woody biomass. In general there is a noticeable gap in literature in terms of application of steam explosion process to upgrade biomass fuel for wood pellet production. In order to study the influence of steam explosion pretreatment on biomass fuel, Salix wood chips was used as raw material. Four different SE experiments were performed by varying two key process factors; time and temperature. Elementary quality and ash properties of the pretreated residue were investigated. Moreover, physical and thermochemical properties of the pellet, produced from the residue, were also investigated. Reduction in ash content especially in alkali metals was observed in steam treated residue. Pretreatment of biomass also enhanced carbon content and reduced oxygen amount in the fuel which enhanced the heating value of the fuel. Moreover, pretreatment enhanced pellet density, impact resistance, and abrasive resistance of pellet. However, small degradation in ash fusion characteristics and char reactivity was also observed as the severity of the process increased.

  • 14.
    Biswas, Amit Kumar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhang, Lan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Nehme, Wassim
    Swiderski, Artur
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Experimental investigation of nitrogen oxides emission and heat transfer for high temperature air combustion2009In: 10th Conference on Energy for a Clean Environment, 2009Conference paper (Refereed)
  • 15. Blasiak, W.
    et al.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Dong, W.
    Combustion performance improvement of grate fired furnaces using Ecotube system2006In: Journal of the Energy Institute, ISSN 1743-9671, Vol. 79, no 2, p. 67-74Article in journal (Refereed)
    Abstract [en]

    This paper presents the main features, advantages and an evaluation of applications of an 'Ecotube' technology for combustion improvement and emission reduction. The sensitivity of the Ecotube locations in a combustion chamber and the injection angle of jets on the Ecotube have been analysed numerically. A municipal solid waste incinerator and a coal fired boiler are the focus of this work. A definition of the heat release distribution ratio is proposed to identify the heat release inside the upper furnace of boilers or incinerators. Results show that an Ecotube system allows a far more uniform heat release, lower CO and NOx emissions, and a more uniform temperature distribution, thus a longer life of the furnace chamber. Additionally, the combustion reaction zone occupies as high as 45% of the whole combustion chamber using an Ecotube system, similar to 40% higher than a conventional multijet mixing system.

  • 16. Blasiak, W.
    et al.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Narayanan, K.
    von Scheele, J.
    Flameless oxyfuel combustion for fuel consumption and nitrogen oxides emissions reductions and productivity increase2007In: Journal of the Energy Institute, ISSN 1743-9671, Vol. 80, no 1, p. 3-11Article in journal (Refereed)
    Abstract [en]

    In order to achieve very low emission of nitrogen oxides, a 'flameless' combustion process that uses oxygen, the so called 'flameless oxyfuel' combustion, has been developed. This new combustion technology is characterised by a lower temperature flame, more uniform temperature distribution and low concentrations of oxygen as well as nitrogen inside the combustion chamber. This work presents a description and the main features of the flameless oxyfuel combustion, the effect of flame structure and temperature on the heat transfer, the comparison of flameless oxyfuel and flameless air fuel combustion results of laboratory tests of new type of flameless oxyfuel burner, as well as examples of industrial applications. This newly developed and applied combustion technology guarantees fuel consumption reduction ( thus CO2 reduction), increase in productivity as well as drastic reduction of nitrogen oxides emission when applied, for example, to thermal treatment processes of wastes, and to the recovery of zinc bearing feed in a rotary kiln.

  • 17.
    Blasiak, Wlodzimierz
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Szewczyk, Dariusz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Lucas, Carlos
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Reforming Of Biomass Wastes Into Fuel Gas With High Temperature Air And Steam2005Report (Other academic)
    Abstract [en]

    The presented work aims to provide information on solid biomass conversion into fuel gas as a result of air and steam gasification process. In contrary to the conventional gasification in this work highly preheated air and steam is used as a gasifying agent. Preheat of air and steam is realised by means of the high-cycle regenerative air/steam preheater. Use of highly preheated gasifying media provides additional energy into the gasification process that enhances the thermal decomposition of the gasified solids. The objective of this work is to provide information on the process of biomass wastes reforming to fuel gas using high temperature air and steam gasification.High Temperature Air/Steam Gasification of biomass wastes has very clear economical and environmental benefits. It will increase consumption of biomass thus decreases CO2 emissions. Apart from CO2 reduction possibility, the new process, High Temperature Gasification has the following advantages:- Clean fuel gas for production of heat or electricity,- No need to treat ashes from gasification since there is no ash or at least no carbon in the ash produced,- No need to landfill since the produced slag can be used for example as a building material.In this work high temperature air and steam gasification of charcoal and wood pellets in a fixed bed updraft gasifier is tested. The following conclusions were found out:

    • For both charcoal and wood pellets gasification cases it was seen that an increase of steam molar fraction in the feed gas decreases the temperature of the gasification, the gasification rate, the mass yield of the fuel and molar fraction of carbon monoxide but increases molar fraction of hydrogen,

    • An increase of the feed gas temperature reduces production of tars, soot and char residue as well as increases calorific value of the fuel gas produced,

    • Preheating of the feed gas obtains a higher gasification efficiency and a higher gasification rate,

    • High temperature air and mixture of air and steam used as feed gas in a fixed bed gasifier shows the capability of this technology of maximising the gaseous product yield,

    • High lower heating value of fuel gas and high molar fraction of hydrogen and hydrocarbons obtained by using high temperature air and steam gasification technology increase the technical possibility of the application of fuel gas produced.

  • 18.
    Blasiak, Wlodzimierz
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    von Scheele, J.
    "Flameless" oxyfuel combustion development for process improvement, emission reduction in furnaces and incinerators2006In: Waste Management and the Environment III / [ed] Popov, V; Kungolos, A; Brebbia, CA; Itoh, H, ASHURST, SOUTHAMPTON: WIT PRESS/COMPUTATIONAL MECHANICS PUBLICATIONS , 2006, Vol. 92, p. 247-256Conference paper (Refereed)
    Abstract [en]

    In recent years, the focus for the development of combustion technology focus has been set on the following main aims: fuel consumption reduction, nitrogen oxides emission reduction, increased productivity and product quality. Fuel consumption reduction has been reduced by as much as 30-40%, and also CO2 emission reduction was achieved by replacing combustion air with oxygen. To achieve very low emission of nitrogen oxides (NOx) the new combustion technology is characterised by: lower temperature of flame, more uniform temperature distribution and reduced concentration of oxygen as well as nitrogen inside the combustion chamber. As in this combustion technique a flame is replaced by a large chemical reaction zone and thus is often not visible the process was named as "flameless" combustion. "Flameless" combustion process that use oxygen, so called oxyfuel combustion, as well as its technical application is the subject of this work. The work presents a description and main features of the "flameless" oxyfuel combustion, results of laboratory tests of a new type of burner, REBOX (R), as well as examples of industrial applications including waste incineration are included.

  • 19.
    Blasiak, Włodzimierz
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Von Schéele, J.
    Oxyfuel flameless combustion for fuel consumption and nitrogen oxides emissions reductions and productivity increase2006In: A and WM, Annual International Conference on Incineration and Thermal Treatment Technologies, 2006, p. 668-685Conference paper (Refereed)
    Abstract [en]

    During last years development of combustion technology focussed the following main aims: fuel consumption reduction, nitrogen oxides emission reduction, increase of productivity and product quality. Fuel savings up to 50%, thus also CO 2 emission reduction, was achieved by replacing combustion air with oxygen. To achieve very low emission of nitrogen oxides (NOx) the new combustion technology is characterised by: lower temperature of flame, more uniform temperature distribution and low concentration of oxygen as well as nitrogen inside combustion chamber. Because in such combustion a flame is replaced by a large chemical reaction zone and thus often is not visible the process was named as flameless combustion. Flameless combustion process with use of oxygen, so called oxyfuel combustion, as well as its technical application is subject of this work. This work presents description and main features of the flameless oxyfuel combustion, results of laboratory tests of new type of flameless oxyfuel burner, as well as examples of industrial applications. This newly developed and applied combustion technology guarantees fuel consumption reduction (thus CO 2 reduction), increase of productivity as well as drastic reduction of nitrogen oxides emission when applied for example to thermal treatment processes of wastes, and a recovery of zinc-bearing feed in a rotary kiln.

  • 20.
    Boström, Mathias
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Multiscale Materials Modelling.
    Huang, Dan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Multiscale Materials Modelling.
    Sernelius, Bo E.
    Lithium atom storage in nanoporous cellulose via surface-induced Li-2 breakage2013In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 104, no 6, p. 63003-Article in journal (Refereed)
    Abstract [en]

    We demonstrate a physical mechanism that enhances a splitting of diatomic Li-2 at cellulose surfaces. The origin of this splitting is a possible surface-induced diatomic-excited-state resonance repulsion. The atomic Li is then free to form either physical or chemical bonds with the cellulose surface and even diffuse into the cellulose layer structure. This allows for an enhanced storage capacity of atomic Li in nanoporous cellulose.

  • 21. Budiman, B. A.
    et al.
    Juangsa, F. B.
    Aziz, M.
    Nurprasetio, I. P.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Experimental verification of interfacial strength effect on the mechanical properties of carbon fiber-epoxy composite2017In: International Journal on Advanced Science, Engineering and Information Technology, ISSN 2088-5334, E-ISSN 2460-6952, Vol. 7, no 6, p. 2226-2231Article in journal (Refereed)
    Abstract [en]

    The effects of carbon fiber-epoxy interfacial strength on the mechanical properties of the corresponding fiber-matrix composites are experimentally demonstrated in this work. Two composites containing different carbon fibers were tested: as-received fibers and fibers soaked in acetone to remove adhesive on their surfaces. The fiber surfaces were first characterized by scanning electron microscopy and time-of-flight secondary-ion mass spectrometry to verify removal of the adhesive. Further, single-fiber fragmentation tests were conducted to evaluate the fiber strength and the interfacial strength. The mechanical properties of the composites were evaluated via tensile testing under longitudinal and transverse loadings. The results show that interfacial strength does not decrease the mechanical properties of the composites under longitudinal loading. In contrast, under transverse loading, the interfacial strength significantly decreases the mechanical properties, specifically the ultimate tensile strength and toughness of the composites.

  • 22. Cao, Xiaohua
    et al.
    Cao, Xiaoling
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhang, Qing
    Nanoscale indentation behavior of pseudo-elastic Ti-Ni thin films2008In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 465, no 1-2, p. 491-496Article in journal (Refereed)
    Abstract [en]

    48.28 at.%Ti-51.72 at.%Ni thin films were prepared by magnetron sputtering and post-annealed at 450, 500, 550 and 600 degrees C, respectively. The evolution of structure, phase transformation and nanoscale indentation behavior of Ti-Ni thin film annealed at different temperature were investigated by X-ray diffractometer (XRD), differential scanning calorimetry (DSC) and nanoindention test, respectively. The results showed that the as-deposited Ti-Ni thin films were amorphous and crystallized after post-annealing. As the annealing temperature increased from 450 to 600 degrees C, both the content of parent phase (B2) and that of the precipitate phase (Ni4Ti3) increased. Both the phase transformation temperature and the micro-hardness of the annealed Ti-Ni thin films increased as well. Meanwhile, the pseudo-elasticity energy recovery ratio 77 first increased to the maximum value and then decreased with the increasing annealing temperature. It revealed that the annealed Ti-Ni thin film specimens exhibited the highest pseudo-elasticity degree with the largest 71 values under the load of 10 mN.

  • 23.
    Cuvila, Carlos Alberto
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Mellin, Pelle
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Saffaripour, M.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Hye, A.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Effect of zeolite on product yield and composition during pyrolysis of hydrothermally pretreated SpruceManuscript (preprint) (Other academic)
  • 24.
    Cuvila, Carlos Alberto
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Mellin, Pelle
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Saffaripour, M.
    Hye, A.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Effect of zeolite on product yield and composition during pyrolysis of hydrothermally pretreated SpruceManuscript (preprint) (Other academic)
  • 25.
    Cuvila, Carlos Alberto
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    The Impact of a Mild Sub-Critical Hydrothermal Carbonization of Pretreatment on Umbila Wood: A Mass and Energy Balance Perspective2015In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, no 3, p. 2165-2175Article in journal (Refereed)
    Abstract [en]

    Over the last years, the pretreatment of biomass as a source of energy has become one of the most important steps of biomass conversion. In this work the effect of a mild subcritical hydrothermal carbonization of a tropical woody biomass was studied. Results indicate considerable change in carbon content from 52.78% to 65.1%, reduction of oxygen content from 41.14% to 28.72% and ash slagging and fouling potential. Even though decarboxylation, decarbonylation and dehydration reactions take place, dehydration is the one that prevails. The mass and energy balance was affected by the treatment conditions than the severity of the treatment.

  • 26.
    Cuvila, Carlos Alberto
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Said, Mahir
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Saffaripour, M.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Effect of mild hydrothermal pretreatment on biomass pyrolysis characteristics and vapors: A Mass and Energy Balance PerspectiveManuscript (preprint) (Other academic)
  • 27.
    Cuvila, Carlos Alberto
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Said, Mahir
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Saffaripour, M.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Effect of mild hydrothermal pretreatment on biomass pyrolysis characteristics and vapors: A Mass and Energy Balance PerspectiveManuscript (preprint) (Other academic)
  • 28.
    Cuvilas, Carlos Alberto
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Mild Wet Torrefaction and Characterization of Woody Biomass from Mozambique for Thermal Applications2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mozambique has vast forestry resources and also considerable biomass waste material such as bagasse, rice husks, sawdust, coconut husks and shells, cashew nut shell and lump charcoal waste. The potential of the total residues from the agricultural sector and the forest industry is estimated to be approximately 13 PJ. This amount of energy covers totally the production of charcoal which amounted to approximately 12.7 PJ in 2006. Although biomass is an attractive renewable source of energy, it is generally difficult to handle, transport, storage and use due to its lower homogeneity, its lower energy density and the presence of non-combustible inorganic constituents, which leads to different problems in energy conversion units such as deposition, sintering, agglomeration, fouling and corrosion. Therefore, a pretreatment of the biomass to solve these problems could lead to a change of current biomass utilization situation. The aim of this study is to convert Mozambican woody biomass residue into a solid biochar that resembles low-grade coal.

    In this work the current energy situation in Mozambique has been reviewed, and the available and potential renewable sources including residues from agricultural crops and forest industry as energy have been assessed. It was found that the country is endowed with great potential for biofuel, solar, hydro and wind energy production. However, the production today is still far from fulfilling the energy needs of the country, and the majority of people are still not benefiting from these resources. Charcoal and firewood are still the main sources of energy and will continue to play a very important role in the near future. Additionally, enormous amounts of energy resources are wasted, especially in the agricultural sector. These residues are not visible on national energy statistics. The chemical composition and the fuelwood value index (FVI) showed that by failing to efficiently utilise residues from Afzelia quanzensis, Millettia stuhlmannii and Pterocarpus angolensis, an opportunity to reduce some of the energy related problems is missed. An evaluation of effect of a mild wet torrefaction pretreatment showed that the chemical composition of the biochar is substantially different than the feedstock. The use of diluted acid as catalysts improves the biochar quality, namely in terms of the energy density and ash characteristics; however, the increment of the S content in the final product should be considered for market acceptance (because the fuels have a maximum allowance for S concentration). The thermal behaviour of the untreated and treated biomass was also investigated. The pyrolytic products of umbila and spruce were affected by the treatment and catalyst in terms of yield and composition of the vapours.

  • 29.
    Cuvilas, Carlos Alberto
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Spruce pretreatment for thermal application: Water, alkaline, and diluted acid hydrolysis2012In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 26, no 10, p. 6426-6431Article in journal (Refereed)
    Abstract [en]

    Hydrolysis a process that involves a separation of the main components of lignocellulosic material (LCM) primarily developed for ethanol production was applied in this work to upgrade biomass for thermal application. The purpose of the pretreatment was to remove hemicellulose and alkali metals and consequently increase the energy content of the biomass and improve the fuel properties. Freshly chopped (2-10 mm) spruce (Picea abies) samples were hydrolyzed (liquid/solid ratio of 800 mL/80 g), using water, diluted acid, and sodium hydroxide in a rotating autoclave at 180 2 ̊C for 150 and 350 min. Several analyses, such as proximate and ultimate analyses, ash composition and fusibility characteristics, and thermogravimetric analysis under pure nitrogen, were performed. Despite the reduction of mass and energy yields with increment of the severity factor, a significant increment of the higher heating value and ash quality was achieved, revealing that hydrolysis using water or diluted acid is a promising method to upgrade biomass as fuel. For alkaline treatment, a huge degradation on the quality of the ash was observed.

  • 30. Danon, B.
    et al.
    Swiderski, Artur
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    de Jong, W.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Roekaerts, D. J. E. M.
    EMISSION AND EFFICIENCY COMPARISON OF DIFFERENT FIRING MODES IN A FURNACE WITH FOUR HiTAC BURNERS2011In: Combustion Science and Technology, ISSN 0010-2202, E-ISSN 1563-521X, Vol. 183, no 7, p. 686-703Article in journal (Refereed)
    Abstract [en]

    Combustion in a furnace equipped with two HiTAC burner pairs, with a thermal power of 100kW(th) each, has been investigated experimentally and computationally. The objective of this study is (1) to observe differences in the performance of the furnace operating in two different firing modes, parallel and staggered, and (2) to explain these differences using detailed CFD simulations. Besides the permanent measurements of temperature, flow and pressure, in-furnace probe measurements of temperature, oxygen and emissions (NO and CO) have been performed. Experimental results show that the efficiency of the furnace was higher in parallel mode compared to staggered mode, 48% and 41% respectively. The values of CO emitted were equal for both firing modes. However, in parallel mode the NOx production was 39 ppm(v)@3%O-2, whereas in staggered mode 53 ppm(v)@3%O-2 NOx was produced. Considering both efficiency and emissions, parallel firing mode performs better than staggered mode. Next, CFD simulations of the furnace were performed in order to explain the observed differences. The simulations were validated with the in-furnace measurements. It was confirmed that the furnace firing in parallel mode achieved a higher efficiency. The radiative heat transfer was higher due to formation of a larger zone with gases with improved radiative properties. In addition, higher velocities along the cooling tubes, due to lower momentum destruction, led to higher convective heat transfer. Also, the lower production of NOx in parallel mode was reproduced by the simulations. This is due to the fact that in parallel mode the fuel jets are merging slower with the combustion air jet, leading to less intense combustion zones. Thus, lower peak temperatures and radical concentrations are achieved, and the NOx production via the thermal and N2O pathways was lower.

  • 31.
    Donaj, Pawel
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Conversion of biomass and waste using highly preheated agents for materials and energy recovery2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One of the greatest challenges of human today is to provide the continuous and sustainable energy supply to the worldwide society. This shall be done while minimizing all the negative consequences of the operation(s) to the environment and its living habitants including human beings, taking from the whole life cycle perspective. In this thesis work new solutions for treatment biomass and waste are analyzed.

     

    Based on the fundamental research on the conversion of various materials (biomass: straw pellets, wood pellets; and waste: plastic waste, ASR residues after pyrolysis), converted by means of different systems (pyrolysis in a fluidized bed reactor, gasification in a fixed-bed reactor using highly preheated agents) it is recommended to classify materials against their charring properties under pyrolysis, in order to find the best destination for a given type of fuel. 

     

    Based on phenomenological research it was found that one of the important effects, affecting performance of downdraft gasifiers, is the pressure drop through the bed and grate. It affects, directly, the velocity profile, temperature distribution and of the height of the bed, especially for the grate with restricted passage surface, although it was not investigated in literature. The lower grate porosity, the higher conversion of fuel and heating value of gas is produced. However, the stability of the process is disturbed; therefore reducing the grate porosity below 20% is not recommended, unless the system is designed to overtake the consequences of the rising pressure inside the reactor. This work proposed the method for prediction of a total pressure drop through the fixed-bed downdraft gasifier equipped with a grate of certain porosity with an uncertainty of prediction ±7.10.  

     

    Three systems have been proposed; one for the treatment of automotive shredder residue (ASR), one for the treatment of plastic waste (polyolefins) and one for biomass (wood/straw pellets). Pyrolysis is an attractive mean of conversion of non-charring materials (like plastic waste) into valuable hydrocarbons feedstock. It gives directly 15-30% gaseous olefins while the residue consisting of naphtha-like feedstock has to be reformed/upgraded to olefins or other chemicals (e.g. gasoline generation) using available petrochemical technologies. Pyrolysis of complex waste mixture such as ASR is an attractive waste pretreatment method before applying any further treatments, whereby useful products are generated (gaseous and liquid fuel) and char, rich in precious metals. The solid residues are meant for further treatment for energy and metals recovery. Gasification is a complementary method for handling pyrolysis residues. However, metals can be removed before gasification. Pyrolysis of charring materials, like biomass, is a very important step in thermo-chemical conversion. However, the char being approximately 25%wt. contains still very high caloric value of about 30MJ/kg. This in connection with the High Temperature Steam Gasification process is a very promising technology for biomass treatment, especially, above 900oC. This enhances the heat transfer towards the sample and accelerates kinetics of the gasification. This, in turn, improves the conversion of carbon to gas, increases the yield of the producer gas and reduces tar content. At higher steam to fuel ratio the process increases the yield of hydrogen, making it suitable for second-generation biofuels synthesis, whereas at lower steam to fuel ratio (S/F<2) the generated gas is of high calorific value making it suitable for power generation in a combined cycle.

  • 32.
    Donaj, Pawel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    High temperature agent gasification of microwave pyrolysed chars from Automotive Shredder Residue2010In: International Conference on Thermal Treatment Technologies and Hazardous Waste Combustors 2010, 2010, p. 459-469Conference paper (Refereed)
    Abstract [en]

    Presently, there is a growing need for handling Automobile Shredder Residues - ASR or "car fluff". One of the most promising methods of treatment ASR is pyrolysis. Apart of obvious benefits of pyrolysis: energy and metals recovery, there is serious concern about residues generated from that process which need to be recycled. Unfortunately, not much work has been reported providing solutions for handling pyrolysis waste's streams. The raw light fraction of ASR, containing mainly foam, textiles and light plastics was gravimetrically separated from the rest of ASR, and treated via microwave pyrolysis to generate 11% of gaseous, 30% of liquid and 59% of solid products, respectively. The resulting char has been characterized and gasified with either a pure steam or 3%vol. oxygen at temperatures between 950-750 °C, respectively, in a lab scale, fixed-bed reactor. The external temperature of gas and the mass loss of sample were continuously recorded. The activity of chars was investigated basing on carbon (ash free basis) conversion during gasification and pyrolysis stage. It was found the char activity decreases with the rise of external gas temperature and with the time of the process. No significant differences between the reactions undergoing with steam and oxygen. This abnormal char behaviour might have been caused the by the inhibiting effect of ash, especially alkali metals on char activity or due to deformation of char structure during microwave heating.

  • 33.
    Donaj, Pawel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Forsgren, Christer
    Conversion of microwave pyrolysed ASR's char using high temperature agents2011In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 185, no 1, p. 472-481Article in journal (Refereed)
    Abstract [en]

    Pyrolysis enables to recover metals and organic feedstock from waste conglomerates such as: automotive shredder residue (ASR). ASR as well as its pyrolysis solid products, is a morphologically and chemically varied mixture, containing mineral materials, including hazardous heavy metals. The aim of the work is to generate fundamental knowledge on the conversion of the organic residues of the solid products after ASR's microwave pyrolysis, treated at various temperatures and with two different types of gasifying agent: pure steam or 3% (v/v) of oxygen. The research is conducted using a lab-scale, plug-flow gasifier, with an integrated scale for analysing mass loss changes over time of experiment, serving as macro TG at 950, 850 and 760 degrees C. The reaction rate of char decomposition was investigated, based on carbon conversion during gasification and pyrolysis stage. It was found in both fractions that char conversion rate decreases with the rise of external gas temperature, regardless of the gasifying agent. No significant differences between the reaction rates undergoing with steam and oxygen for char decomposition has been observed. This abnormal char behaviour might have been caused by the inhibiting effects of ash, especially alkali metals on char activity or due to deformation of char structure during microwave heating.

  • 34.
    Donaj, Pawel J.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Izadpanah, Mohammad Reza
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Effect of Pressure Drop Due to Grate-Bed Resistance on the Performance of a Downdraft Gasifier2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 11, p. 5366-5377Article in journal (Refereed)
    Abstract [en]

    The grate-bed resistance coefficient appears to be an important operating parameter having a strong influence on the overall performance during downdraft fixed-bed gasification- it affects, directly, the velocity profile, temperature distribution, and height of the bed. To date no information on the pressure drop due to the grate-bed resistance has been found. The objective of this paper is to propose a correlation that can predict the total effectof pressure drop (caused by bed resistance and grate-bed resistance), through a grate of a certain surface porosity (open area/total area) covered by the porous bed. The term related to the grate-bed resistance is based on the effective grate porosity, which combined surface bed porosity with geometrical criteria of the grate. Based on this a new term has been integrated into the Ergun’s equation. The prediction has been validated within the experimental work conducted on a 0.7MW downdraft fixed-bed gasifier fueled with wood pellets. In this study, three grates of different porosities and thicknesses have been tested using various operating conditions. The predicted values of pressure drop showed a good agreement within the experimental results with ±7.10% of uncertainty. Although, the lower grate porosity, the higher conversion of fuel and heating value of gas is produced, the stability of the process is disturbed; therefore the grate porosity reduction below 20% is not recommended.

  • 35.
    Donaj, Pawel J.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kaminsky, W.
    Buzeto, F.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Pyrolysis of plastic waste for recovery of monomers and naphtha-like feedstockIn: Journal of Waste Management, ISSN 2356-7724, E-ISSN 2314-6052Article in journal (Other academic)
    Abstract [en]

    Pyrolysis of plastic waste is an alternative way of plastic recovery and could be a potential solution for the increasing stream of solid waste. The objective of this work was to increase the yield the gaseous olefins (monomers) as feedstock for polymerization process and to test the applicability of a commercial Ziegler-Natta (Z-N): TiCl4/MgCl2 for cracking a mixture of polyolefins consisted of 46 % wt. of LDPE, 30% wt. ofHDPE and 24 % of PP. Two sets of experiments have been carried out at 500oC and 650oC via catalyticpyrolysis (1% of Z-N catalyst) and at 650oC and 730oC via only-thermal pyrolysis. These experiments have been conducted in a lab-scale, fluidized quartz-bed reactor of a capacity of 1-3kg/h at Hamburg University. The results revealed a strong influence of temperature and presence of catalyst on the product distribution. The ratios of gas/liquid/solid mass fractions via thermal pyrolysis were: 36.9/48.4/15.7%wt. and 42.4/44.7/13.9%wt. at650oC and 730oC while via catalytic pyrolysis were: 6.5/89.0/4.5%wt. and 54.3/41.9/3.8%wt. at 500oC and 650oC, respectively. At 650oC the monomer generation increased by 55% up to 23.6 %wt. of total pyrolysis products distribution while the catalyst was added. Obtained yields of olefins were compared with the naphtha steam cracking process and other potentially attractive processes for feedstock generation. The concept of closed cycle material flow for polyolefins has been discussed, showing the potential benefits of feedstock recycling in a plastic waste management.

  • 36.
    Donaj, Pawel J.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kaminsky, W.
    Buzeto, F.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Pyrolysis of polyolefins for increasing the yield of monomers' recovery2012In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 32, no 5, p. 840-846Article in journal (Refereed)
    Abstract [en]

    Pyrolysis of plastic waste is an alternative way of plastic recovery and could be a potential solution for the increasing stream of solid waste. The objective of this work was to increase the yield the gaseous olefins (monomers) as feedstock for polymerization process and to test the applicability of a commercial Ziegler-Natta (Z-N): TiCI4/MgCl2 for cracking a mixture of polyolefins consisted of 46% wt. of low density polyethylene (LDPE), 30% wt. of high density polyethylene (HDPE) and 24% wt. of polypropylene (PP). Two sets of experiments have been carried out at 500 and 650 C via catalytic pyrolysis (1% of Z-N catalyst) and at 650 and 730 degrees C via only-thermal pyrolysis. These experiments have been conducted in a lab-scale, fluidized quartz-bed reactor of a capacity of 1-3 kg/h at Hamburg University. The results revealed a strong influence of temperature and presence of catalyst on the product distribution. The ratios of gas/liquid/solid mass fractions via thermal pyrolysis were: 36.9/48.4/15.7% wt. and 42.4/44.7/13.9% wt. at 650 and 730 degrees C while via catalytic pyrolysis were: 6.5/89.0/4.5% wt. and 54.3/41.9/3.8% wt. at 500 and 650 degrees C, respectively. At 650 degrees C the monomer generation increased by 55% up to 23.6% wt. of total pyrolysis products distribution while the catalyst was added. Obtained yields of olefins were compared with the naphtha steam cracking process and other potentially attractive processes for feedstock generation. The concept of closed cycle material flow for polyolefins has been discussed, showing the potential benefits of feedstock recycling in a plastic waste management.

  • 37.
    Donaj, Pawel J.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Wlodzimierz, Blasiak
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Conversion of Industrially Processed Biomass Waste into Value-added Products Using High Temperature Agents2011In: International Conference on Thermal Treatment Technologies and Hazardous Waste Combustors, 2011Conference paper (Refereed)
    Abstract [en]

    Biomass can be utilized for energy and chemicals generation, gradually replacing the significance of fossil fuels. In this work the conversion of an industrially processed biomass waste (straw pellets) has been studied by means of High Temperature Steam Gasification (HTSG) and High Temperature Pyrolysis (HTP) at T=750-950oC and at three levels of steam to fuel ratio (S/F): 3.2; 1.875 and 0. The primary objectives are focused on a parametric study in which the emphasis is put on the influence of temperature and S/F on the reaction rate, conversion of carbon to gas, as well as yields, composition and heating value of generated Syngas. The results show the increasing trend in the reaction rate, hydrogen yield and tar cracking with an increase in agent temperature and S/F. However, this growth is significantly increased for the temperatures around 950oC. The yield of gas varied from 1.2 to 1.5 Nm3/kg for HTP to 1.5 to 2.5 Nm3/kg for HTSG and the LHV ranged between 8-13MJ/Nm3. At highest S/F the reduction of CO and hydrocarbons is observed even at 850oC yielding amount of hydrogen by 100% up to 38% compared with a lower S/F. Pyrolysis and lower S/F generated gas suitable for energetic purpose, whereas higher S/F for chemical synthesis.

  • 38.
    Donaj, Pawel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Forsgren, Christer
    Stena Metall AB.
    Recycling of automobile shredder residue with a microwave pyrolysis combined with high temperature steam gasification2010In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 182, no 1-3, p. 80-89Article in journal (Refereed)
    Abstract [en]

    Presently, there is a growing need for handling automobile shredder residues - ASR or "car fluff". One of the most promising methods of treatment ASR is pyrolysis. Apart of obvious benefits of pyrolysis: energy and metals recovery, there is serious concern about the residues generated from that process needing to be recycled. Unfortunately, not much work has been reported providing a solution for treatment the wastes after pyrolysis. This work proposes a new system based on a two-staged process. The ASR was primarily treated by microwave pyrolysis and later the liquid and solid products become the feedstock for the high temperature gasification process. The system development is supported within experimental results conducted in a lab-scale, batch-type reactor at the Royal Institute of Technology (KTH). The heating rate, mass loss, gas composition, LHV and gas yield of producer gas vs. residence time are reported for the steam temperature of 1173K. The sample input was 10 g and the steam flow rate was 0.65 kg/h. The conversion reached 99% for liquids and 45-55% for solids, dependently from the fraction. The H-2:CO mol/mol ratio varied from 1.72 solids and 1.4 for liquid, respectively. The average LHV of generated gas was 15.8 MJ/N m(3) for liquids and 15 MJ/N m(3) for solids fuels.

  • 39.
    Donaj, Pawel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Włodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Forsgren, C.
    Kinetic study of decomposition of ASR residues after pyrolysis in inert and oxidative atmosphere2009In: International Thermal Treatment Technologies (IT3) & Hazardous Waste Combustors (HWC) Joint Conference 2009: Cincinnati, Ohio, USA, 18 - 21 May 2009, 2009, p. 465-483Conference paper (Refereed)
    Abstract [en]

    The kinetic studies on solid residues after pyrolysis from ASR (Automobile Shredder Residue) originated from STENA Metall AB have been performed with the use of thermogravimetry analysis TGA. The char after microwave pyrolysis has been pyrolyzed and combusted in the presence of helium and air respectively. The TG experiments have been performed with heating rate of 10, 20, 40, 60 and 100deg/min. The influence of heating rate for decomposition rate and the char reactivity was also analyzed. Three different decomposition peaks have been identified for pyrolysis process in the range of temperatures 230-430, 400-500 and 680-850°C, respectively. The activation energy (E act) and pre-exponential (frequency) factor (A) were calculated from the DTG curves using Coats and Redfern (C&amp;R) method and Doyle's (D), based on the assumption of an independent, parallel first order Arrhenius-type global kinetic model. The kinetic data were also obtained for small lab scale gasification process of ASR pyrolysis residues. The mass loss and the heating of sample are recorded. It was proved, that the char's heating rate plays a significant role in the conversion rate as well in the char reactivity. The relatively high ignition temperature of 630°C would require the steam temperature to be well above 800°C. Thus, reasonable would be to use high temperature steam gasification for treating ASR residues after microwave pyrolysis.

  • 40. Evangelopoulos, Panagiotis
    et al.
    Persson, Henry
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Kantarelis, Efthymios
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology. KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Pyrolysis of waste electrical and electronic equipment (WEEE) on a single screw reactor for bromine free oil productionManuscript (preprint) (Other academic)
    Abstract [en]

    This study focuses on pyrolysis on waste electrical and electronic equipment or WEEE as it is usually referred in the literature. A new auger reactor has been designed and tested with WEEE material. The performance of the reactor as well as the fate of the bromine has been investigated and evaluated in order to be used for designing of industrial process. The mass balance calculations performed for the tested cases of 400, 500 and 600 °C, showed a high gas yield (44%) at the temperature of 600 °C, which can be used to fulfil the process energy needs. At the low temperature of 400 °C the oil production reach its maximum yield, while the bromine content of the oil has also a maximum percentage of 0.5% wt. Several valuable compounds have been detected in the oil composition, which can be used either as fuels or for feedstock recycling.

  • 41. Flamme, Michael
    et al.
    Milani, Ambrogio
    Wünning, Joachim
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Szewczyk, Dariusz
    Sudo, Jun
    Mochida, Susumu
    Radiant Tube Burners2010In: Industrial Combustion Testing / [ed] Charles E Baukal, Taylor & Francis Group, 2010, p. 487-504Chapter in book (Other academic)
  • 42.
    Gunarathne, Duleeka
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Chmielewski, Jan Karol
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    High temperature air/steam gasification of steam exploded biomass2013In: Finnish – Swedish Flame Days 2013, 2013Conference paper (Refereed)
    Abstract [en]

    Pretreatment of biomass under high pressure steam is called steam explosion. Hydrophobic dark coloured pellets (here referred as Black pellets) produced from this pretreatment technology were used in gasification experiments with both pure air and air-steam mixture as gasifying agents at an updraft High Temperature Air/steam Gasification (HTAG) unit. For comparison purpose, similar experiments were carried out with un-pretreated biomass pellets (referred as Gray pellets). Black pellets show the possibility to co-gasification with peat. Require less volume but, with high height to diameter ratio of the gasifier. High temperature gasification is preferred but decomposes at low temperature resulting around two times higher CO/CO2 ratio. With Black pellets, CO and hydro carbon contents of syngas is higher while H2 contentis higher with Gray pellets. Air gasification gave higher Lower Heating Value (LHV) with Black pellets compared to Gray pellets and was around 7.3 MJ/Nm3. Gas yields were higher with Gray pellets and they were more efficient in air gasification and efficiency was around 79.5% with higher Equivalence Ratio (ER). With steam addition to the feed gas of Black pellets result in syngas with LHV of 10.6MJ/Nm3 compared to 8.2 MJ/Nm3 with Gray pellets. Steam addition has reduced the gas yield of both pellet types. Efficiency was higher with Black pellets around 76.9%.Black pellets gave slightly more tar content in syngas compared to Gray pellets and was composed of mainly secondary tar while Gray pellets gave more tertiary tar. Cases with steam and high ER lowered the tar content. Under the tested conditions, Indene/Naphthalene ratio can be used to predict the tar content even when steam was added. In general, steam gasification of Black pellets is more feasible if syngas with high energy value is desired. But, Gray pellets with high ER was most efficient and contained lowest tar. If higher H2 yield is preferred, unpretreated pellets are more attractive.

  • 43.
    Gunarathne, Duleeka
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Chmielewski, Jan Karol
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Performance of High Temperature Air/Steam Gasification of Hydrothermal Carbonized Biomass2014In: 22nd European Biomass Conference and Exhibition, 2014, p. 626-631Conference paper (Refereed)
    Abstract [en]

    In order to effectively use the biomass resources for thermal applications, use of biomass pretreatment technologies like hydrothermal carbonization are emerging. With the aim of studying the gasification performance of hydrothermal carbonized biomass (biocoal) in high temperature air/steam medium, gasification of two types of biocoal pellets produced from spent grain and horse manure, was carried out in a fixed bed updraft gasifier. Steam gasification gave syngas having 10-11 MJ/Nm3 of LHV with both types of biocoal. The syngas yield and thus cold gas efficiency was higher with gasification of spent grain biocoal, but syngas purity in terms of tar and particulates was better with gasification of horse manure biocoal.

  • 44.
    Gunarathne, Duleeka
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Cuvilas, Carlos
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Li, Jun
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Weihong, Yang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    BIOMASS PRETREATMENT FOR LARGE PERCENTAGE BIOMASS CO-FIRING2014Conference paper (Refereed)
    Abstract [en]

    With the target of reducing net GHG emissions from coal fired power plants, biomass co-firing in such plants is becoming more and more attractive option among other thermal applications of biomass such as combustion, gasification and pyrolysis. Not only CO2, but effective reduction of SOx and NOx emissions can also be expected with this low cost, sustainable and renewable energy option. However, the economic feasibility of such process largely depends on the cost of biomass acquisition and transportation. Therefore, local availability of large quantities of biomass is important for more economic co-firing. Since always this is not the case, pretreatment of biomass to increase energy density is another way to make biomass economical for long distance transportation. Pretreatment also broaden the usage of biomass sources (eg. wet and waste biomass), reduce the moisture content make it hydrophobic reducing drying energy demand, ease to comminute into small particles creating it more economical source for co-firing. Further, as a result of pretreatment, combustion and electricity generation efficiencies will be improved due to increased heating value of pretreated biomass. Therefore, enhancement of biomass properties is advisable not only to improve its inferior characteristics as well as to make it as suitable alternative for fossil fuels. In this paper, the technologies of biomass pretreatment for thermal application, such as physical and thermochemical pretreatments were reviewed. The upgrading processes of biomass including steam explosion, torrefaction and hydrothermal carbonization-HTC were described based on the HHV, adiabatic flame temperature, fouling tendency and emissions. Furthermore, a case study using severely torrified biomass for large percentage co-firing with coal is discussed.

  • 45.
    Gunarathne, Duleeka
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Mellin, Pelle
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Weihong, Yang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Pettersson, Magnus
    Ljunggren, Rolf
    System integration of the heat treatment furnace in steel plant with biomass gasification process2015Conference paper (Refereed)
  • 46.
    Gunarathne, Duleeka Sandamali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Chmielewski, Jan Karol
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Pressure drop prediction of a gasifier bed with cylindrical biomass pellets2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 113, p. 258-266Article in journal (Refereed)
    Abstract [en]

    Bed pressure drop is an import parameter related to operation and performance of fixed bed gasifiers. Up to date, limited literature is found on pressure drop prediction of beds with cylindrical pellets and none was found for gasifying beds with cylindrical pellets. In this paper, an available pressure drop prediction correlation for turbulent flows in a bed with cylindrical pellets which has used equivalent tortuous passage method was extended for a gasifier bed with shrinking cylindrical pellets and for any flow condition. Further, simplified graphical representations introduced based on the developed correlation can be effectively used as a guide for selecting a suitable pellet size and designing a grate so that it can be met the system requirements. Results show that the method formulated in the present study gives pressure drop approximation within 7% deviation compared to measured values with respect to performed runs. Available empirical correlation with modified Ergun constants for cylindrical pellets gave pressure drop within 20% deviation after the effect of shrinkage was taken into account.

  • 47.
    Gunarathne, Duleeka Sandamali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Mueller, Andreas
    Fleck, Sabine
    Kolb, Thomas
    Chmielewski, Jan Karol
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Gasification Characteristics of Hydrothermal Carbonized Biomass in an Updraft Pilot-Scale Gasifier2014In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, no 3, p. 1992-2002Article in journal (Refereed)
    Abstract [en]

    Biocoal pellets were gasified in an updraft high-temperature agent gasification (HTAG) unit with preheated air at 900 degrees C to study the performance of the air gasification of hydrothermal carbonized biomass. In comparison to raw biomass, hydrothermal carbonization increased the carbon content from 46 to 66% and decreased the oxygen content from 38 to 16%. As a result, the heating value of biomass on a dry basis was increased from 19 to 29 MJ/kg after hydrothermal carbonization. Thermogravimetric analysis (TGA) of biocoal featured early decomposition of hemicellulose and a shoulder attached to the cellulose peak corresponding to lignin decomposition. Char gasification demonstrated a peak near conversion of 0.2. Syngas with 7.9 MJ Nm(-3) lower heating value (LHV) was obtained from gasification experiments performed in the pilot-scale gasifier. The maximum cold gas efficiency was 80% at the lowest equivalence ratio (ER) and also resulted in high-purity syngas. The LHV and cold gas efficiency were higher than that of the previously studied unpretreated biomass pellets. The fuel conversion positively correlated with the fuel residence time in the bed, and almost 99% conversion could be achieved for a residence time of 2 h. The superficial velocity (or hearth load) and specific gasification rate were higher than the reported values of updraft gasifiers because of the high-temperature operation and specific fuel used.

  • 48.
    Gunarathne, Duleeka Sandamali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Mueller, Andreas
    Fleck, Sabine
    Kolb, Thomas
    Chmielewski, Jan Karol
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Gasification characteristics of steam exploded biomass in an updraft pilot scale gasifier2014In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 71, p. 496-506Article in journal (Refereed)
    Abstract [en]

    Pretreatment of biomass becomes more and more important due to the large scale application of biomass having low energy density. In this paper, steam exploded biomass pellets (Black pellets) and unpretreated biomass pellets (Gray pellets) were gasified with air and steam at an updraft HTAG (High Temperature Agent Gasification) unit. Decomposition characteristics of pellets were first analyzed with TGA (thermo gravimetric analysis). Early decomposition of hemicellulose and cellulose were seen with Black pellets around 241 degrees C and 367 degrees C respectively. Introducing CO2 led comparatively high mass loss rate with Black pellets. Gasification of Black pellets resulted in syngas with high CO and hydrocarbon contents while Gasification of Gray pellets resulted in high H-2 content of syngas. LHV (lower heating value) of syngas was high around 7.3 MJ/Nm(3) and 10.6 MJ/Nm(3) with air gasification and steam gasification respectively. Even with significantly low syngas temperature with gasification of Black pellets, only slightly high total tar content was seen compared to that of Gray pellets gasification. Phenolic compounds dominated the tar composition. In general, steam gasification of Black pellets seems to be more feasible if syngas with high energy value is desired. If higher H-2 yield is preferred, gasification of unpretreated pellets likely to be more attractive.

  • 49.
    Han, Tong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Sophonrat, Nanta
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Evangelopoulos, Panagiotis
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Persson, Henry
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Weihong, Yang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin2018In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 33, p. 162-168Article in journal (Refereed)
    Abstract [en]

    Sulfonated Kraft lignin, the most available commercial lignin of today, has high sulfur content due to the extraction and the subsequent sulfonation processes. In this work, the evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin has been studied. Fast Pyrolysis experiments have been done using Py-GC/MS. It is found that main sulfur-containing products in the pyrolytic vapors are present as the following small molecular compounds: H2S, SO2, CH3SH, CH3SCH3, and CH3SSCH3. This indicates that sulfur-containing radicals preferentially combine with the other small radicals such as H and CH3 during fast pyrolysis process. Sulfur is suggested to be mainly present as sulfite (SO3) and sulfide (S) in the sulfonated Kraft lignin. Sulfite that is incorporated into lignin during the sulfonation process mainly result in the formation of SO2. The nature of the sulfur links created during the Kraft pulping process is difficult to determine, but they are supposed to mainly exist in form of sulfide (S) bonds, which lead to the formation of H2S, CH3SH, CH3SCH3 and CH3SSCH3.

  • 50.
    Han, Tong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sophonrat, Nanta
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Tagami, Ayumu
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Sevastyanova, Olena
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Mellin, P.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem2019In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 235, p. 1061-1069Article in journal (Refereed)
    Abstract [en]

    Technical lignin particles melt under relatively low temperature. This results in the problem in the continuous feeding and fluidization during lignin pyrolysis, which in turn limits its utilization on a large scale. In this study, two most available types of lignin have been used to investigate the lignin melting problem, which are Kraft lignin (KL) from pulping process and hydrolysis lignin (HL) from bio-ethanol production process. Elemental composition, thermal property and thermally decomposed derivatives of each sample are tested by elemental analyzer, TGA, DSC, and Py-GC/MS. Morphology, structure and crystal change before and after heat treatment are tested by microscopy, FTIR and XRD. All results suggest that lignin structure determines its melting properties. Kraft lignin from pulping process contains a less cross-linked structure. It melts under heating. On the other hand, hydrolysis lignin from hydrolysis process contains a highly crossed-linked and condensed structure. It does not melt before decomposition under heat treatment. Modifying lignin structure is suggested for the resolution of technical lignin melting problem.

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