Change search
Refine search result
123 1 - 50 of 125
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 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, 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.

  • 12.
    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.

  • 13.
    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.

  • 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.
    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.

  • 17.
    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.

  • 18.
    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.

  • 19.
    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.

  • 20.
    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.

  • 21.
    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.

  • 22.
    Fakhrai, Reza
    et al.
    KTH, Superseded Departments, Metallurgy. KTH, Superseded Departments, Materials Science and Engineering.
    Blasiak, Wlodzimierz
    KTH, Superseded Departments, Materials Science and Engineering.
    Combustion Performance of the Kraft Recovery Boiler Versus Black Liquor PropertiesIn: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227Article in journal (Other academic)
  • 23.
    Fakhrai, Reza
    et al.
    KTH, Superseded Departments, Metallurgy.
    Blasiak, Wlodzimierz
    KTH, Superseded Departments, Metallurgy.
    Numerical Simulation of Black Liquor Combustion in Kraft Recovery Boiler1998In: Exposé över Förbränningsforskning i Sverige, 1998Conference paper (Other academic)
  • 24.
    Fakhrai, Reza
    et al.
    KTH, Superseded Departments, Metallurgy.
    Blasiak, Wlodzimierz
    Theoretical Analysis of Interaction Between Fuel Drop and Walls during Black Liquor Combustion in a Kraft Recovery Furnace2001In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227Article in journal (Other academic)
  • 25. 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)
  • 26.
    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.

  • 27.
    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.

  • 28.
    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.

  • 29.
    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.

  • 30.
    Kantarelis, Efthymios
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Liu, Junli
    Yang, Weihong
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Sustainable Valorization of Bamboo via High-Temperature Steam Pyrolysis for Energy Production and Added Value Materials2010In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 24, p. 6142-6150Article in journal (Refereed)
    Abstract [en]

    Bamboo is an abundant plant in many Asian countries and especially in China, it has an extremely rapid growing rate, and It can be considered as a sustainable wood resource In this paper a comparative study of pyrolysis of bamboo in the presence of high temperature steam and an inert atmosphere (N-2) as well as characterization of products has been conducted Evaluation of experimental results showed that faster devolatilization can be achieved in the presence of high-temperature steam Furthermore, the gas composition indicates interaction of steam with vapors and solid species even at low temperatures Analysis of the obtained liquid after steam pyrolysis at 797 K revealed that the H/C and O/C ratios in the liquid are 1 54 and 0 16, respectively The characteristics of the products indicate possible exploitation of derived char as an activated carbon precursor, a reducing agent in metallurgical processes, or a solid fuel for gasification and combustion processes The composition of the liquid fraction suggests further exploitation as a liquid fuel and/or chemical feedstock

  • 31.
    Kantarelis, Efthymios
    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.
    Biomass pyrolysis  for energy and fuels production2013In: Technologies for Converting Biomass to Useful Energy: Combustion, Gasification, Pyrolysis, Torrefaction and Fermentation / [ed] Erik Dahlquist, CRC Press, 2013, p. 245-277Chapter in book (Refereed)
  • 32.
    Kantarelis, Efthymios
    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.
    Effect of zeolite to binder ratio on product yields and composition during catalytic steam pyrolysis of biomass over transition metal modified HZSM52014In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 122, p. 119-125Article in journal (Refereed)
    Abstract [en]

    Catalytic pyrolysis of biomass over metal modified zeolites (multifunctional catalysts) is a very promising route for production of hydrocarbons and less oxygenated liquid feedstock suitable for fuels and/or chemicals. In this work the effect of zeolite to binder ratio (Z/B) of a metal modified HZSM5, on products yields and composition during steam pyrolysis of biomass has been investigated. Increased zeolite content resulted in lower liquid yield and increased coke formation; however, more deoxygenated liquids obtained at higher zeolite loadings. Char yield is not significantly affected by the zeolite content. Declining catalytic activity is observed at longer time on stream because of coke deposition. While acidic function of the catalyst deoxygenates carboxylic acids and carbonyls, metal functions seem to selectively convert phenols and methoxy phenols. Competitive steam adsorption on the acid sites of the zeolite seems to lower the conversion to aromatics. The high availability of acid sites, at higher zeolite loading, increases aromatics concentration exponentially. Increased yields of hydrogenated products have been obtained indicating that the Ni-V/HZSM5 catalyst exhibits some hydrogenation activity.

  • 33.
    Kantarelis, Efthymios
    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.
    Effects of Silica-Supported Nickel and Vanadium on Liquid Products of Catalytic Steam Pyrolysis of Biomass2014In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, no 1, p. 591-599Article in journal (Refereed)
    Abstract [en]

    Catalytic steam pyrolysis of biomass was performed in a bubbling fluidized-bed reactor at 450 degrees C, and the effects of silica-supported transition metals (Ni and V) on product yields and compositions have been investigated. Both metals seem to be catalytically active and altered the liquid composition. An interesting finding is the in situ reduction of the supported nickel oxide to metallic Ni during the pyrolysis reactions, which can enhance H-transfer. Vanadia-containing catalysts show higher selectivity in reduction of carboxylic acids and ketones. An increased aldehyde content, especially for the bimetallic Ni-V catalyst, suggests that selective deoxygenation can take place via the Mars van Krevelen (MvK) mechanism. Ni catalysts showed activity for aromatics formation, while both metals showed selectivity in producing phenols instead of catechols. Assessment of the catalytic performance indicates that both metals could be interesting candidates for incorporation in other support materials and evaluation of the derived modified catalysts in biomass steam pyrolysis.

  • 34.
    Kantarelis, Efthymios
    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.
    Investigation on the effect of space time of nickelvanadium modified HZSM5 on products and coke formation during catalytic steam pyrolysis of biomassManuscript (preprint) (Other academic)
  • 35.
    Kantarelis, Efthymios
    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.
    Production of Liquid Feedstock from Biomass via Steam Pyrolysis in a Fluidized Bed Reactor2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 8, p. 4748-4759Article in journal (Refereed)
    Abstract [en]

    The nature of liquids derived from biomass fast pyrolysis is far from typical oil, and thus, different approaches for bio-oil production and upgrading are needed. In this paper the steam pyrolysis of a pine and spruce wood mixture in a bubbling fluidized bed is investigated. Particularly, the effect of steam to biomass ratio and temperature in relation to products yields and composition has been studied. Products analyses indicate that steam presence affects the yields and composition of all the products (gas, char, liquid) and promotes oxygen removal from the liquid. Increased liquid yields with significantly lower amount of carboxylic acids and higher effective hydrogen index (EHI) were obtained, which makes them more suitable for further upgrading. The levoglucosan (LGA) concentration in the produced liquid is higher compared with conventional N-2 pyrolysis, which suggests that steam pyrolylsis can be regarded as an alternative for production of fermentable sugars. Polycondensation reactions are hindered by steam presence while steam seems to act as a hydrogen donor; however, increased water content is a problem that has to be considered as well.

  • 36.
    Kantarelis, Efthymios
    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, C.
    Zabaniotou, A.
    Thermochemical treatment of E-waste from small household appliances using highly pre-heated nitrogen-thermogravimetric investigation and pyrolysis kinetics2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 3, p. 922-929Article in journal (Refereed)
    Abstract [en]

    The EU directive on waste of electrical and electronic equipment (WEEE) 2002/96/EC has set a goal of recovering 70-80% in terms of materials and energy. Nowadays, thermal cracking (pyrolysis) of such waste streams is receiving renewed attention, due to the energy and material recovery that can be achieved and therefore the sustainable waste management. However, it still lacks the kinetic background which is of great importance for a successful design of thermochemical processes. In this study the kinetic parameters of WEEE (originating from small household appliances) pyrolysis using highly pre-heated nitrogen under six different heating rates (1-2.5 K/s) have been estimated using a combination of model-free and model fitted methods. Even though WEEE is heterogeneous material, similar behavior at each of the six different heating rates applied was observed. The activation energy of the pyrolysis process determined with two different model-free methods gave comparable results. Pre-exponential factor and reaction order were determined using the Coats-Redfern method. The estimated kinetic parameters for the WEEE pyrolysis are: E = 95.54 kJ/mol, A = 1.06 x 10(8) and n = 3.38.

  • 37.
    Kantarelis, Efthymios
    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.
    Biomass pyrolysis for energy and fuel production2013In: Technologies for Converting Biomass to Useful Energy: Combustion, Gasification, Pyrolysis, Torrefaction and Fermentation, CRC Press , 2013, p. 245-278Chapter in book (Other academic)
    Abstract [en]

    Pyrolysis is the thermochemical decomposition of organic matter in the absence of oxygen and produces a wide range of useful products. The word is coined from the Greek-derived elements pyr "ρ-fire” and lysis "λUsσς-breakdown/separation” emphasizing the disintegration of matter due to heat. It is a standalone process or one of several reaction steps in gasification and combustion processes1 and is considered as the basic thermochemical process to produce valuable fuels and energy from biomass. Pyrolysis is also known as thermolysis, thermal cracking, dry distillation, destructive distillation, etc.; however, there are differences in those terms. During pyrolysis, complex macromolecules of biomass break down into relatively smaller molecules producing 3 major products which can be classified as follows: •a solid residue (which mainly consists of carbon and ash) known as char•gases (mainly CO, CO2, CH4, H2 and other light hydrocarbons)•Vapors/liquids known as bio-oil or bio-crude (mainly oxygenates, aromatics, water, products of low degree of polymerization, tars, etc.)

  • 38.
    Krishnamurthy, Narayanan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Paul, P. J.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Studies on low-intensity oxy-fuel burner2009In: PROCEEDINGS OF THE COMBUSTION INSTITUTE, ISSN 1540-7489, Vol. 32, p. 3139-3146Article in journal (Refereed)
    Abstract [en]

    This paper presents experimental and computational results of oxy-fuel burner operating on classical flame and flameless mode for heat release rate of 26 kW/m(3). The uniqueness of the burner arises from a slight asymmetric injection of oxygen at near sonic velocities. Measurements of temperature, species, total heat flux, radiative heat flux and NOx emission were carried out inside the furnace and the flow field was computationally analyzed. The flame studies were carried Out for coaxial flow of oxygen and fuel jets with similar inlet velocities. This configuration results in slow mixing between fuel and oxygen and the flame is developed at distance away from the burner and the flame is bright/white in colour. In the flameless mode a slight asymmetric injection of the high velocity oxygen jet leads to a large asymmetric recirculation pattern with the recirculation ratio of 25 and the resulting flame is weak bluish in colour with little soot and acetylene formation. The classical flame in comparison is characterised by soot and acetylene formation, higher NOx and noise generation. The distribution of temperature and heat flux in the furnace is more uniform with flameless mode than with flame mode.

  • 39. Kubik, Katarzyna
    et al.
    Donaj, Pawel J.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    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, Włodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Christer, F.
    Assessment of ASR treatment using pyrolysis and reforming of its residences for small scale electricity generation systems2008In: Air and Waste Management Association, 2008, p. 717-726Conference paper (Refereed)
    Abstract [en]

    Due to the increased manufacturing of new vehicles, older ones the so called end-of-life vehicle's (ELV) are being disposed more frequently. The EU ELV directive (entered into force 21/10/2000) sets targets and objectives that must be obeyed by the member states. Under this directive from 01/01/2006 for all ELV, the reuse and recovery rate should be min. 85% (by weight) and min. 80% (by weight) rate of recycling. From 01/01/2015 for all ELV, the reuse and recovery rate should be min. 95% (by weight) and min. 85% (by weight) rate of recycling. Because of the lack of a cost-effective technology to recycle this waste, it is mostly land filled, smaller amounts are incinerated. In this work, basing on the reviewing of the available technological methods, a new thermal treat system for ASR is proposed: Firstly, a microwave pyrolysis of ASR is used. During this pyrolysis process, metals will be successfully recycled, and also generate by-products such as pyrolysis gas, oil, and char. These by-products will be further reformed using high-temperature steam gasification to generate high-purity synthetic gas, which will be used for a small-scale electricity generation system. Energy and mass balance of the whole system will be done. The electricity generation efficiency will be assessed.

  • 40.
    Li, Jun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Biagini, Enrico
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Tognotti, Leonardo
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Flame characteristics of pulverized torrefied-biomass combusted with high-temperature air2013In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 160, no 11, p. 2585-2594Article in journal (Refereed)
    Abstract [en]

    In this work, the flame characteristics of torrefied biomass were studied numerically under high-temperature air conditions to further understand the combustion performances of biomass. Three torrefied biomasses were prepared with different torrefaction degrees after by releasing 10%, 20%, and 30% of volatile matter on a dry basis and characterized in laboratory with standard and high heating rate analyses. The effects of the torrefaction degree, oxygen concentration, transport air velocity, and particle size on the flame position, flame shape, and peak temperature are discussed based on both direct measurements in a laboratory-scale furnace and CFD simulations. The results primarily showed that the enhanced drag force on the biomass particles caused a late release of volatile matter and resulted in a delay in the ignition of the fuel-air mixture, and the maximum flame diameter was mainly affected by the volatile content of the biomass materials. Furthermore, oxidizers with lower oxygen concentrations always resulted in a larger flame volume, a lower peak flame temperature and a lower NO emission. Finally, a longer flame was found when the transport air velocity was lower, and the flame front gradually moved to the furnace exit as the particle size increased. The results could be used as references for designing a new biomass combustion chamber or switching an existing coal-fired boiler to the combustion of biomass.

  • 41.
    Li, Jun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Bonvicini, Giorgio
    Tognotti, Leonardo
    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 rapid devolatilization of biomasses with varying degrees of torrefaction2014In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 122, p. 261-269Article in journal (Refereed)
    Abstract [en]

    Torrefied biomass is a coal-like fuel that can be burned in biomass boilers or co-fired with coal in co-firing furnaces. To make quantitative predictions regarding combustion behavior, devolatilization should be accurately described. In this work, the devolatilization of three torrefied biomasses and their parent material were tested in an isothermal plug flow reactor, which is able to rapidly heat the biomass particles to a maximum temperature of 1400 degrees C at a rate of 10(4) degrees C/s, similar to the conditions in actual power plant furnaces. During every devolatilization test, the devolatilized biomass particles were collected and analyzed to determine the weight loss based on the ash tracer method. According to the experimental results, it can be concluded that biomass decreases its reactivity after torrefaction, and the deeper of torrefaction conducted, the lower the biomass reactivity. Furthermore, based on a two-competing-step model, the kinetic parameters were determined by minimizing the difference between the modeled and experimental results based on the least-squares objective function, and the predicted weight losses exhibited a good agreement with experimental data from biomass devolatilization, especially at high temperatures. It was also detected that CO and H-2 are the primary components of the released volatile matters from the devolatilization of the three torrefied biomasses, in which CO accounts for approximately 45-60%, and H-2 accounts for 20-30% of the total volatile species.

  • 42.
    Li, Jun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Brzdekiewicz, A.
    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.
    Co-firing based on biomass torrefaction in a pulverized coal boiler with aim of 100% fuel switching2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 99, p. 344-354Article in journal (Refereed)
    Abstract [en]

    Torrefied biomass has several benefits, such as higher energy density, good grindability, higher flowability and uniformity. The process of torrefaction moves the chemical and physical properties of raw biomass close to that of bituminous coal, which allows co-utilization with high substitution ratios of biomass in the existing coal-fired boilers without major modifications. In this study, a torrefaction based co-firing system was proposed and studied. Devolatilization and char oxidize kinetics of the torrefied biomass have been investigated experimentally. CFD modeling of co-firing with varying substitutions of torrefied biomass in a pulverized coal boiler have been carried out. To figure out the boiler performance when co-firing torrefied biomass, five different cases were involved and simulated, coal only, 25% biomass, 50% biomass, 75% biomass, and 100% biomass on thermal basis, respectively. The results showed torrefaction is able to provide a technical option for high substitution ratios of biomass in the co-firing system. The case-study pulverized coal boiler could be fired 100% torrefied biomass without obvious decreasing of the boiler efficiency and fluctuation of boiler load. More positively, the net CO 2 and the NO x emissions significantly reduced with increasing of biomass substitutions in the co-firing system.

  • 43.
    Li, Jun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Jankowski, R.
    Kotecki, M.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Szewczyk, D.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Brzdekiewicz, A.
    Numerical analysis of loads effect on combustion performance and NO x emissions of a 220 MW pulverized coal boiler2012In: Cleaner Combustion and Sustainable World - Proceedings of the 7th International Symposium on Coal Combustion, Springer Berlin/Heidelberg, 2012, p. 675-683Conference paper (Refereed)
    Abstract [en]

    This paper presents numerical study on the combustion performance and NOx emissions of a 220 MW pulverized coal boiler. Three different loads have been simulated with combusting coal, 200MW, 170MW and 140MW respectively. In order to get as precise as possible numerical analysis results, two-step simulation method has been adopted in this work, namely, air supply system simulation and furnace simulation. After air supply system simulation, the results have been taken as the initial and boundary conditions for furnace simulation. The comparison between the measured values and predicted results from 200MW case shows much better agreement. According to the simulation results, the adopted two-step simulation method is reasonable and suitable for predicting the characters of the flow and combustion process. It is concluded that the distributions of temperature, O 2 and CO concentration inside furnace with different loads shows good similarly. The total NOx emissions decreased with the boiler load reducing, and fuel NOx has the same trend as total NOx, and fuel NOx account for about 66% in total NOx in all the three cases. More important, thermal NOx slowly decreased with the rise of boiler load. More detailed results presented in this paper enhance the understanding of combustion processes and complex flow patterns of Front- Wall pulverized coal boilers.

  • 44.
    Li, Jun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Jankowski, Radoslaw
    Kotecki, Michal
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Szewczyk, Dariusz
    Brzdekiewicz, Artur
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    CFD Approach for Unburned Carbon Reduction in Pulverized Coal Boilers2012In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 26, no 2, p. 926-937Article in journal (Refereed)
    Abstract [en]

    Low-NO, technologies are widely used in pulverized coal boilers, but they usually produce high levels of carbon in the fly ash. High levels of unburned carbon represent fuel loss, so the overall boiler efficiency is reduced. Additionally, the higher carbon content affects the suitability of fly ash for cement applications. The purpose of this paper is to provide a CFD approach for unburned carbon reduction by optimizing operating conditions. In this paper, three different boiler loads were simulated: 200 MW, 170 MW, and 140 MW. The air supply System was simulated previously for preparing as precise as possible boundary conditions. At last, the unburned carbon level of every burner was investigated, and the effects of residue residence time and the local fuel air momentum ratio are discussed in detail. According to the predicted results, operating conditions and the residence time of the coal particles affects the unburned carbon level in fly ash. Operating conditions play a more significant role during the combustion process, while the residence time affects char burnout only when the burner's location is low. Therefore, it is concluded that a cost-effective method could be developed for reducing the unburned carbon level in ash and correspondingly, the loss on ignition level. First, it is necessary to determine which burners are operating under poor conditions through CFD analysis. Then, the fuel air momentum ratios of those burners should be modified by changing the operating conditions, meanwhile increasing the residence time of coal particles to ensure complete combustion.

  • 45.
    Li, Jun
    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.
    Torrefaction for fuel switching from coal to pure biomass in power plants2013In: Proceedings of the ASME Power Conference 2013: presented at ASME 2013 power conference, July 29-August 1, 2013, Boston, Massachusetts, USA, ASME Press, 2013, p. V001T01A009-Conference paper (Refereed)
    Abstract [en]

    Torrefaction changes the elementary composition of biomass and moves it towards to coal, and accordingly, torrefaction based co-firing system in a pulverized coal boiler have been proved as a promising option for direct co-firing with a large percentage of biomass. This work examined and assessed various torrefaction degrees influencing on emissions reductions and system performances in a 200MWe power plant. The raw PKS was torrefied at four different torrefaction temperatures, namely, 200°C, 250°C, 270°C, and 300°C, respectively. A series of analyses were performed to understand the impacts of torrefaction temperatures on mill power requirements, pollutions emissions, and boiler efficiency. According to the results, an enhanced torrefaction caused more energy consumption on biomass pretreatment process but less energy consumption on biomass grinding. When considering the boiler efficiency and emissions in together, torrefaction temperature of 275 °C is property option both for high boiler efficiency of 95% and a lower NOx emission of 100 mg/Nm3. A high torrefaction temperate is required when expecting an even lower NOx emission, but the boiler efficiency would be reduced at the same time. Therefore, a balance consideration of combustion efficiency and emission should be made for torrefaction based biomass-fired boiler.

  • 46.
    Li, Jun
    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.
    Ponzio, Anna
    Volumetric combustion of biomass for CO2 and NOx reduction in coal-fired boilers2012In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 102, p. 624-633Article in journal (Refereed)
    Abstract [en]

    To meet the urgent environmental targets, substituting coal with biomass has been considered to be an effective and promising method over the last decades. In this paper, a new concept of volumetric combustion is proposed and further developed to achieve 100% fuel switching to biomass in large scale coal-fired boilers. Volumetric combustion not only changes the in-furnace flow but also affects the combustion reactions by the intensive mixing and internal recirculation of the flue gases. Firstly, the volumetric combustion properties of the wood pellets were investigated experimentally. An Aspen model was then used to thermodynamically describe and study the volumetric combustion with three different types of fuel, and the emission properties of CO2 and NOx were compared. Finally, two applications of volumetric combustion were discussed. It is concluded that the wood pellets ignited and combusted much faster than the coal pellets and had a larger combustion volume when combusted under lower oxygen concentration conditions, and the ignition time was almost independent of the oxygen concentration when the oxidizer was preheated to 1000 degrees C. In addition, the NOx emissions decreased as the recirculation ratio of the flue gas increased, and as the percentage of biomass used in co-firing increased, the amount of flue gas that needs to be recycled for reduction of NOx decreased. Thus, the volumetric combustion is beneficial as it reduces the operation cost of NOx reduction. The volumetric combustion would be an attractive technology for co-firing a large proportion of biomass in coal-fired boilers with high boiler efficiency and effective emissions reduction.

  • 47.
    Li, Jun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhang, Xiaolei
    Department of Mechanical Engineering, University of Alberta, Edmonton, Canada.
    Pawlak-Kruczek, Halina
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kruczek, P.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Process simulation of co-firing torrefied biomass in a 220 MWe coal-fired power plant2014In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 84, p. 503-511Article in journal (Refereed)
    Abstract [en]

    Torrefaction based co-firing in a pulverized coal boiler has been proposed for large percentage of biomass co-firing. A 220 MWe pulverized coal-power plant is simulated using Aspen Plus for full understanding the impacts of an additional torrefaction unit on the efficiency of the whole power plant, the studied process includes biomass drying, biomass torrefaction, mill systems, biomass/coal devolatilization and combustion, heat exchanges and power generation. Palm kernel shells (PKS) were torrefied at same residence time but 4 different temperatures, to prepare 4 torrefied biomasses with different degrees of torrefaction. During biomass torrefaction processes, the mass loss properties and released gaseous components have been studied. In addition, process simulations at varying torrefaction degrees and biomass co-firing ratios have been carried out to understand the properties of CO2 emission and electricity efficiency in the studied torrefaction based co-firing power plant. According to the experimental results, the mole fractions of CO2 and CO account for 69-91% and 4-27% in torrefied gases. The predicted results also showed that the electrical efficiency reduced when increasing either torrefaction temperature or substitution ratio of biomass. A deep torrefaction may not be recommended, because the power saved from biomass grinding is less than the heat consumed by the extra torrefaction process, depending on the heat sources.

  • 48.
    Li, Jun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhang, Xiaolei
    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.
    Effects of Flue Gas Internal Recirculation on NOx and SOx Emissions in a Co-Firing Boiler2013In: International Journal of Clean Coal and Energy, ISSN 2168-1538, Vol. 2, no 2, p. 13-21Article in journal (Refereed)
    Abstract [en]

    Volumetric combustion has been developed to realize a high substitution ratio of biomass in co-firing boilers, which features an intensive flue gas internal recirculation inside furnace. However, the characteristics of NOx and SOx emissions in large-scale boilers with volumetric combustion were not fully clear. In this paper, an Aspen Plus model of volumetric combustion system was built up based on a co-firing boiler. In order to characterize the reductions of NOx and SOx, three biomass substitution ratios were involved, namely, 100% biomass, 45% biomass with 55% coal, and 100% coal. The effects of flue gas recirculation ratio, air preheating temperature, oxygen concentration, and fuel types on pollutants emission in the volumetric combustion system were investigated. According to the results, it was concluded the higher substitution ratio of biomass in a co-firing boiler, the lower emissions of NOx and SOx. Moreover, flue gas internal recirculation is an effective pathway for NOx reduction and an increased recirculation ratio resulted in a significant decreasing of NOx emission; however, the SOx increased slightly. The influences of air preheating temperature and O2 concentration on NOx emission were getting weak with increasing of recirculation ratio. When 10% or even higher of flue gas was recycled, it was observed that almost no NOx formed thermodynamically under all studied conditions. Finally, to reach a low emission level of NOx, less energy would be consumed during biomass combustion than coal combustion process for internal recirculation of flue gas.

  • 49.
    Lille, Simon
    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.
    Jewartowski, Marcin
    Experimental study of the fuel jet combustion in high temperature and low oxygen content exhaust gases2005In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 30, no 2-4, p. 373-384Article in journal (Refereed)
    Abstract [en]

    The performance of high temperature air combustion (HiTAC) depends oil the heat regenerator efficiency and on the way fuel is mixed with furnace gases. In this work. combustion of a fuel jet of gasol (>95% of propane) was investigated experimentally. Experiments were carried out in steady-state conditions using a single jet flame furnace. The jet of fuel was co-axially injected into high temperature exhaust gases generated by means of a gas burner also fired with gasol. Thus. instead of highly preheated and oxygen depleted air, which was normally used by other researches for such studies. this work has used high temperature and low oxygen content exhaust gases as the oxidiser. A water-cooled fuel nozzle was used to control fuel inlet temperature. Influence of the oxygen content in the oxidiser. at temperatures of 860-890 degreesC, on the flame visibility and the reactants composition was investigated. The combustion of gasol in hot flue cyases appeared to be very stable and complete even at very low oxygen concentration. The oxygen concentration in the oxidiser was found to have a substantial effect on flame size, luminosity, colour, visibility and lift-off distance. Reduced oxygen concentration increases the flame size and lift-off distance, and decreases luminosity and visibility. The HiTAC flame first became bluish and then non-visible at sufficiently low concentration of oxygen in the oxidiser. In this work. results are presented for the constant ratio between fuel Jet velocity and velocity of co-flowing flue gases. ThB ratio was equal to 26.

  • 50.
    Liu, H.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology. Huazhong University of Science and Technology, China .
    Saffari Pour, Mohsen
    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.
    Grip, C. -E
    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.
    A thermodynamic study of hot syngas impurities in steel reheating furnaces: Corrosion and interaction with oxide scales2014In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 77, p. 352-361Article in journal (Refereed)
    Abstract [en]

    Environmental concerns lead industries to implement gasified biomass (syngas) as a promising fuel in steel reheating furnaces. The impurities of syngas as well as a combination with iron oxide scale form complex mixtures with low melting points, and might cause corrosion on steel slabs. In this paper, the effects of syngas impurities are thermodynamically investigated, when scale formation on the steel slabs surface simultaneously takes place. A steel reheating furnace can be divided into preheating, heating, and soaking zones where the temperature of a steel slab changes respectively. Therefore, the thermodynamic calculation is performed at different temperatures to predict the fate of impurities. Then, the stable species are connected with respective zones in a reheating furnace. It is concluded that reactions due to alkali compounds, chloride, and particulate matter could take place on steel slabs. In the low temperature range, interaction of sodium chloride occured with pure iron prior to scale formation. Then, at high temperature the reactions of impurities are notable with iron oxides due to scale growing. Furthermore, the multicomponent reactions with syngas impurities showed that most of alkali contents evaporate at first stages, and only small amounts of them remain in slag at high temperature.

123 1 - 50 of 125
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf