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  • 1.
    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.

  • 2.
    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.

  • 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.
    High temperature steam gasification of straw pelletsManuscript (preprint) (Other academic)
  • 4.
    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.

  • 5.
    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.

  • 6.
    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.

  • 7.
    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)
  • 8.
    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)
  • 9.
    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.

  • 10.
    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)
  • 11. 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.

  • 12. 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.

  • 13.
    Blasiak, Wlodzimierz
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Narayanan, Krishnamurthy
    KTH, Superseded Departments, Materials Science and Engineering.
    Yang, Weihong
    KTH, Superseded Departments, Materials Science and Engineering.
    Evaluation of new combustion technologies for CO2 and NOX reduction in steel industries2004In: AIR POLLUTION XII / [ed] Brebbia, CA, 2004, Vol. 14, p. 761-771Conference paper (Refereed)
    Abstract [en]

    The paper presents state-of-the-art combustion technologies for heating applications in the steel industry. Two types of burners that exhibit dilution combustion were evaluated in this study carried out in a semi-industrial furnace. These were regenerative air-fuel burner and oxy-fuel burner. The tests with regenerative air-fuel were carried out applying operation both with and without oxygen-enrichment. The main parameters studied for the different types of burners and operations include heat flux, thermal efficiency, and NOX at different levels of in-leakage of air. The in-flame parameters were measured including temperature, gas composition, total and radiative heat fluxes. All the studied burners provide a high efficiency of fuel utilization, a large 'flame' with uniform temperature and heat flux profiles. The results also clearly indicate that NOX emissions can be maintained at low or even very low levels well (less than 100 mg/MJ of fuel) meeting the restrictions at industrial-scale operation.

  • 14.
    Blasiak, Wlodzimierz
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Yang, Weihong
    KTH, Superseded Departments, Materials Science and Engineering.
    Rafidi, Nabil
    KTH, Superseded Departments, Materials Science and Engineering.
    Physical properties of a LPG flame with high-temperature air on a regenerative burner2004In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 136, no 4, p. 567-569Article in journal (Refereed)
  • 15.
    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.

  • 16.
    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.

  • 17.
    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)
  • 18.
    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)
  • 19.
    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.

  • 20.
    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)
  • 21.
    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)
  • 22.
    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.

  • 23. 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.

  • 24.
    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.

  • 25.
    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.

  • 26.
    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.

  • 27.
    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.

  • 28.
    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.

  • 29.
    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.

  • 30.
    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.

  • 31.
    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&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.

  • 32.
    Evangelopoulos, Panagiotis
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Arato, Samantha
    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.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Reduction of brominated flame retardants (BFRs) in plastics from waste electrical and electronic equipment (WEEE) by solvent extraction and the influence on their thermal decompositionIn: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456Article in journal (Refereed)
    Abstract [en]

    Consumption of electronics increases due to modern society’s growing needs, which leads to increasing generation of waste electrical and electronic equipment (WEEE). Recycling of WEEE has been a global concern during the last few decades because of the toxic compounds that are produced during recycling. Different recycling techniques have been adapted on a commercial scale in order to overcome this issue, but the recycling of WEEE still lacks the technology to treat different kinds of feedstocks and to maximise the recycling rates. Pyrolysis is an alternative that has not been commercialised yet. One of the challenges for the implementation of this technology is the toxic brominated organic compounds that can be found in the pyrolysis oils.

    In this study, tetrabromobisphenol A (TBBPA), one of the major flame retardants, is reduced in three different WEEE fractions through solvent extraction as a treatment prior to pyrolysis. Two solvents have been experimentally investigated: isopropanol and toluene, the latter of which can be derived from pyrolysis oil. The results indicate that TBBPA was extracted during pre-treatment. Moreover, the total bromine content of WEEE material was reduced after the treatment with a maximum reduction of 36.5%. The pyrolysis experiments indicate that reduction of several brominated organic compounds was achieved in almost all the tested cases, and two brominated compounds (2,4,6-tribromophenol and 2,5-Dibromobenzo(b)thiophene) reached complete removal. Also, the thermal decomposition behaviour of the raw samples and the treated was investigated, showing that the reduction of TBBPA influences the decomposition by shifting the starting decomposition temperature.

  • 33.
    Evangelopoulos, Panagiotis
    et al.
    KTH, School of Industrial Engineering and Management (ITM).
    Arvelakis, Stylianos
    National Technical University of Athens.
    Kantarelis, Efthymios
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Experimental investigation of low temperature pyrolysis of printed circuit boards (PCBs) and printed circuit board components (PCB sockets)Manuscript (preprint) (Other academic)
    Abstract [en]

    Printed circuit boards (PCBs) are the heart of all electronics due to their compact size and the broad spectrum of applications but very challenging when their life ends. Recycling of these components is problematic since they consist of different metallic parts packed on plastic compressed cover. The present study focuses on low temperature pyrolysis of PCBs since this process can separate the organic fraction from the inorganics. The latter, enables further separation and purification of the metals which are not oxidized during mild treatment. The low Br content of the resultant char after treatment at 320 oC for 30 min indicates that it could be used as solid fuel if efficient separation from the inorganic part would be performed. Moreover, the liquids obtained by this process can be used for feedstock recycling since the results indicates that toxic bromine containing on the organic compounds has been decreased both by increasing the residence time of pyrolysis process or by increasing the temperature conditions.

  • 34.
    Evangelopoulos, Panagiotis
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Kantarelis, Efthymios
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Experimental Investigation of Pyrolysis of Printed Circuit Boards for Energy and Materials Recovery under Nitrogen and Steam Atmosphere2017In: 8th International Conference on Applied Energy, ICAE 2016; Beijing; China; 8 October 2016 through 11 October 2016, Elsevier, 2017, Vol. 105, p. 986-991Conference paper (Refereed)
    Abstract [en]

    Printed circuit boards (PCB) are one of the most challenging fractions of e-waste in terms of material recycling and energy recovery. In this study, pyrolysis of PCBs in inert and steam atmosphere has been investigated as a valuable alternative for energy recovery of the organic fraction with simultaneous recycling of metals. The decomposition of two different PCB fractions has been investigated by means of thermogravimetric analysis (TGA) and lab scale pyrolysis experiments in steam and nitrogen atmospheres. The composition of the gas obtained from the pyrolysis experiments was strongly influenced by the reactive atmosphere. The characterization of the solid residue by X-ray Powder Diffraction (XRD) and scanning electron microscopy (SEM) showed high influence of steam to the migration of the antimony in the produced vapors.

  • 35.
    Evangelopoulos, Panagiotis
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Kantarelis, Efthymios
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Experimental investigation of the influence of reaction atmosphere on the pyrolysis of printed circuit boards2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, p. 1065-1073Article in journal (Refereed)
    Abstract [en]

    Printed circuit boards (PCB) are one of the most challenging fractions of waste electrical and electronic equipment (WEEE) in terms of recycling due to their complexity and diversity. Pyrolysis seems to be a promising alternative for production of energy carriers from its organic fraction with simultaneous recovery of metals. Reaction atmosphere is among the process parameters that affects the thermal decomposition as well as the products’ formation and distribution. In this study, the decomposition of two different PCB fractions in inert and steam atmospheres has been investigated by means of thermogravimetric analysis (TGA) and lab scale fixed bed reactor experiments. It was found that the decomposition of the tested materials in steam atmosphere starts at lower temperatures and proceeds slower compared to the N2 atmosphere. Moreover, a two-step decomposition has been observed on the PCB sockets fraction due to the fact that high amount of antimony oxide was present, a common additive for improving the flame retardancy, which have been also observed on previous studies (Wu et al., 2014). The presence of steam influence the pyrolysis gas composition and promotes additional vaporisation of antimony as verified by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). Finally, the liquid fraction has been qualitatively analysed using a GC/MS in order to determine the brominated compounds as well as other compounds that are produced from this process.

  • 36.
    Evangelopoulos, Panagiotis
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Kantarelis, Efthymios
    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.
    Investigation of the thermal decomposition of printed circuit boards (PCBs) via thermogravimetric analysis (TGA) and analytical pyrolysis (Py-GC/MS)2015In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 115, p. 337-343Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is to experimentally investigate the pyrolytic behavior of printed circuit boards (PCBs) waste fraction at a temperature range of 400 °C to 900 °C by means of thermogravimetric analysis (TGA) and analytical pyrolysis (Py-GC/MS) was carried out. The experimental results reveal that the chemical composition of the PCBs and the relatively high ash content (=79% w/w) are strongly connected with the high quantity of metals and ceramic materials. The main decomposition of PCBs occurs between 250 °C and 370 °C. The pyrolysis of PCBs showed a varying production of aromatic compounds such as phenol, bromophenol, styrene, methylstyrene, and bisphenol A as well as non-aromatic compounds such as acetone and bromomethane, which are strongly related with the initial chemical composition of PCBs. Moreover, Py-GC/MS revealed that temperature increase favours the production of aromatic hydrocarbons, while the phenol which is the most abundant compound produced, shows an opposite trend, as a result of its further decomposition to simpler products. Furthermore, brominated compounds produced, such as bromomethane and bromophenol, are derived from the flame retardant used during the manufacturing process and in that case the Py-GC/MS showed a slight decrease of brominated compounds with increase in temperature.

  • 37. 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.

  • 38.
    Evangelopoulos, Panagiotis
    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.
    Jilvero, Henrik
    Stena Recycling Int AB, Dept Res & Dev, POB 4088, S-40040 Gothenburg, Sweden..
    Weihong, Yang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Investigation on the low-temperature pyrolysis of automotive shredder residue (ASR) for energy recovery and metal recycling2018In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 76, p. 507-515Article in journal (Refereed)
    Abstract [en]

    The automotive shredder residue (ASR) or shredder light fraction (SLF) is the remaining fraction from the metal recovery of end-of-life vehicles (ELVs). While processes for metal recovery from ELVs are well developed, the similar process for ASR remains a challenge. In this work, low-temperature pyrolysis of the ASR fraction was investigated under the assumption that a low temperature and inert environment would enhance the metal recovery, i.e. the metals would not be further oxidised from their original state and the organic material could be separated from the metals in the form of volatiles and char. Pyrolysis experiments were performed in a tube reactor operating at 300, 400 and 500 degrees C. The gas and oil obtained by pyrolysis were analysed by micro-GC (micro-Gas Chromatography) and GC/MS (Gas Chromatography/Mass Spectrometry), respectively. It was found that the gas produced contained a high amount of CO2, limiting the energy recovery from this fraction. The oil consisted of a high concentration of phenolic and aromatic compounds. The solid residue was crushed and fractionated into different particle sizes for further characterization. The pyrolysis temperature of 300 degrees C was found to be insufficient for metal liberation, while the char was easier to crush at tested temperature of 400 and 500 degrees C. The intermediate temperature of 400 degrees C is then suggested for the process to keep the energy consumption low.

  • 39. 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)
  • 40. Gadek, W.
    et al.
    Mlonka-Medrala, A.
    Prestipino, M.
    Evangelopoulos, Panagiotis
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Kalisz, S.
    Weihong, Yang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Gasification and pyrolysis of different biomasses in lab scale system: A comparative study2016In: 1ST INTERNATIONAL CONFERENCE ON THE SUSTAINABLE ENERGY AND ENVIRONMENT DEVELOPMENT (SEED 2016), EDP Sciences, 2016, article id UNSP 00024Conference paper (Refereed)
    Abstract [en]

    Gasification and pyrolysis are very promising technologies for clean energy production especially from low rank fuels. Biomass and wastes with high chlorine, alkali and even heavy metals content are fuels preferential for thermal utilization. However, several problems during combustion in conventional steam boilers occurs e.g. slagging, fouling, chlorine corrosion, boiler efficiency deterioration. New efficient and cost effective technologies are needed, even in small-scale applications. The main objective of this work was to compare the thermochemical behaviour and process parameters effects of different biomass under air gasification and pyrolysis conditions. Three important fuels for European power industry were selected: woody biomass and two residual biomass, such as oat straw and dried citrus wastes. In order to evaluate the possibility to use different feedstocks or to combine and/or integrate them in thermochemical processes, a comparison among typical and untypical feedstocks is needed. Tests performed on small scale fixed bed reactor show the gas yield, its composition and LHV parameter. The results were performed in Royal Institute of Technology (KTH) in Sweden during BRISK program (Biofuels Research Infrastructure for Sharing Knowledge).

  • 41.
    Ghadamgahi, Mersedeh
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. Ovako Hofors AB, Hofors, Sweden .
    Ölund, P.
    Lugnet, A.
    Saffaripour, Mohsen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Design optimization of flameless-oxyfuel soaking pit furnace using CFD technique2014In: Energy Procedia, 2014, Vol. 61, p. 611-614Conference paper (Refereed)
    Abstract [en]

    The effect of the combustion chamber’s configuration on the characteristics of flow and combustion parameters has been numerically investigated for a multi injecting, LPG, Flameless Oxy-fuel burner in a real-size soaking pit furnace, using CFD simulation. The simulation has been performed on two different furnace configurations, namely; small and large chambers of 15 m3 and 27 m3, with a height to width ratios of 1.49 and 2.02 respectively and with corresponding burner capacities of 560 kW and 900 kW. A major experimental trial has been performed in order to validate the results and reasonable consistency has been observed. The predicted results, with particular focus on the temperature distribution and heat transfer rate of two cases have been studied in detail.

  • 42. Gomez, R. Y.
    et al.
    Nuran, Zaini Ilam
    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.
    Helsen, L.
    Landfill solid waste-based syngas purification by a hybrid pulsed corona plasma unit2019In: European Biomass Conference and Exhibition Proceedings, ETA-Florence Renewable Energies , 2019, p. 520-522Conference paper (Refereed)
    Abstract [en]

    Gasification of excavated Municipal Solid Waste (MSW) for energy and materials recovery has been seen as a solution for current energetic, environmental and land availability issues. However, it poses many technological challenges, and among them the most difficult is to obtain of a tar-free syngas. In this work, two set of experiments were performed in order to obtain a syngas from MSW with a low tar content. In the first stage, MSW gasification was performed in order to identify the tar yield and composition at different temperatures using air and steam. After that, the most representative tar compound, naphthalene, was selected to perform tar cracking experiments in a pulsed corona plasma reactor able to operate from ambient temperature up to 1200ᵒC. The results of these experiments show that the pulsed corona plasma can enhance the tar thermal cracking reactions, reducing by 200ᵒC the temperature at which 100% of the naphthalene is converted.

  • 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.
    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.

  • 44.
    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.

  • 45.
    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.

  • 46.
    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)
  • 47.
    Gunarathne, Duleeka S.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Mellin, Pelle
    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. Swerea KIMAB AB, Sweden.
    Pettersson, M.
    Ljunggren, R.
    Performance of an effectively integrated biomass multi-stage gasification system and a steel industry heat treatment furnace2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 170, p. 353-361Article in journal (Refereed)
    Abstract [en]

    The challenges of replacing fossil fuel with renewable energy in steel industry furnaces include not only reducing CO2 emissions but also increasing the system energy efficiency. In this work, a multi-stage gasification system is chosen for the integration with a heat treatment furnace in the steel powder industry to recover different rank/temperature waste heat back to the biomass gasification system, resulting higher system energy efficiency.A system model based on Aspen Plus was developed for the proposed integrated system considering all steps, including biomass drying, pyrolysis, gasification and the combustion of syngas in the furnace. Both low temperature (up to 400 °C) and high temperature (up to 700 °C) heat recovery possibilities were analysed in terms of energy efficiency by optimizing the biomass pretreatment temperature.The required process conditions of the furnace can be achieved by using syngas. No major changes to the furnace, combustion technology or flue gas handling system are necessary for this fuel switching. Only a slight revamp of the burner system and a new waste heat recovery system from the flue gases are required.Both the furnace efficiency and gasifier system efficiency are improved by integration with the waste heat recovery. The heat recovery from the hot furnace flue gas for biomass drying and steam superheating is the most promising option from an energy efficiency point of view. This option recovers two thirds of the available waste heat, according to the pinch analysis performed. Generally, depending on the extent of flue gas heat recovery, the system can sustain up to 65% feedstock moisture content at the highest pyrolysis temperature studied.

  • 48.
    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.

  • 49.
    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.

  • 50.
    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.

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