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  • 201.
    Zhang, Qinglin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Dor, Liran
    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.
    Eulerian Model for Municipal Solid Waste Gasification in a Fixed-Bed Plasma Gasification Melting Reactor2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 9, p. 4129-4137Article in journal (Refereed)
    Abstract [en]

    Plasma gasification melting (PGM) is a promising waste-to-energy process, which provides many features superior to those of conventional gasification. In this work, a steady Euler Euler multiphase model is developed to predict the performance of municipal solid waste (MSW) gasification inside a PGM reactor. The model considers the main chemical and physical processes, such as drying, pyrolysis, homogeneous reactions, heterogeneous char reactions, and melting of the inorganic components of MSW. The model is validated by one experimental test of a pilot reactor. The characteristics of PGM gasification, such as temperature distribution, syngas composition, tar yield, and energy conversion ratio (ECR, chemical energy of the gas phase divided by the total energy input), at the proposed condition are discussed. A total of nine cases are used to investigate the effects of the equivalence ratio (ER) and plasma power with a fixed flow rate of MSW. It is found that the ER has a positive effect on the cold gas efficiency of PGM gasification. However, the increase of the ER is restricted by the peak temperature. The influence of the plasma power then is not obvious for PGM gasification.

  • 202.
    Zhang, Qinglin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Dor, Liran
    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.
    Properties and optimizing of a plasma gasification & melting process of municipal solid waste2010In: International Conference of Thermal Treatment Technology & Hazardous Waste Combustors, 2010, p. 296-316Conference paper (Refereed)
    Abstract [en]

    A new solid waste treatment method called Plasma Gasification & Melting (PGM) has been developed by Environmental Energy Resources Ltd. (EER). In this technology, high temperature plasma air and steam arc used to convert the waste into high-quality combustible syngas and vitreous benign slag. Due to the special features of the technology it is applicable for various stream of the solid waste field such as MSW, Medical Waste (MW) and Low Level Radioactive Waste (LLRW), where the technology was derived from. The aim of this study is to discuss the characteristics of this technology, and find out the optimal operation condition for a PGM plant. A simulation model of the PGM process was built up and validated by the test results of a PGM demonstration plant. The result shows that the syngas LCV of PGM is much higher than that of traditional gasification. For air gasification, there exists a lower limit of air/MSW mass ratio for 100% conversion of MSW. When the air/MSW mass ratio exceeds the limitation, the syngas LCV will descend by dilution of CO2 and N2. The tar yield will decrease, because of higher pyrolysis temperature. For air/steam gasification, high temperature steam as gasification agent can reduce the limitation of air/MSW mass ratio, so further enhance the syngas quality. The influence of plasma power will be more prominent for air/steam gasification than air gasification. Based on above discussion, an optimizing conception design aiming at producing syngas with high LCV and energy efficiency of a PGM process is suggested.

  • 203.
    Zhang, Qinglin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Dor, Liran
    Zhang, Lan
    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 analysis of municipal solid waste gasification with steam in a Plasma Gasification Melting reactor2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 98, p. 219-229Article in journal (Refereed)
    Abstract [en]

    Plasma Gasification Melting (PGM) is a novel gasification technology which offers a promising treatment of low-heating-value fuels like municipal solid waste (MSW), medical waste (MW) and other types of waste. By considering the differences in pyrolysis characteristics between cellulosic fractions and plastics in MSW, a semi-empirical model was developed to predict the performance of the PGM process. The measured results of MSW air and steam gasification in a PGM demo-reactor are demonstrated and compared with the model predicted results. Then, the effects of dimensionless operation parameters (ER. PER, and SAMR) are discussed. It was found that all three numbers have positive effects on system cold gas efficiency (CGE). The reasons can be attributed to promoted tar cracking by enhanced heat supply. The effects of PER and ASME on syngas LHV are also positive. The influence of ER on syngas pyrolysis can be divided into two parts. When 0.04 < ER < 0.065, the effect of ER is on LHV positive; when 0.065 < ER < 0.08, the effect of ER is positive. This phenomenon was explained by two contradictory effects of ER. It is also found that interactions exist between operation parameters. For example, increasing PER narrows the possible range of ER while increasing SAMR broadens possible ER range. Detail extents for those operation parameters are demonstrated and discussed in this paper. Finally, the optimal point aiming at obtaining maximum syngas LHV and system CGE are given.

  • 204.
    Zhang, Qinglin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Wu, Yueshi
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Dor, L.
    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 analysis of solid waste gasification in the Plasma Gasification Melting process2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 405-413Article in journal (Refereed)
    Abstract [en]

    Plasma Gasification Melting is a promising technology for solid waste treatment. In this work, a thermodynamic analysis has been conducted to evaluate the advantages and limitations of the PGM technology. According to the characteristics of the PGM, the whole process was divided into four sections such as drying, pyrolysis, char gasification and inorganics melting. The energy and exergy in each section has been calculated. According to different usage of syngas, two kinds of energy and exergy efficiencies are defined. The results show that the PGM process produces a tar-rich syngas. When considering the raw syngas (syngas with tar), the energy and exergy efficiency of PGM process is very high. The effects of operating conditions on the thermodynamic performance of the PGM process have been analyzed. Considering the energy and exergy of clean syngas, it is beneficial to increase sensible heat input to the PGM system. However, high sensible heat input or high steam injection is not suggested when considering the energy and exergy efficiency of raw syngas.

  • 205.
    Zhang, Xiaolei
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Micro-reaction Mechanism Study of the Biomass Thermal Conversion Process using Density Functional Theory2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Biomass, or bio-energy, is one of the most important alternative energies because of environmental concerns and the future shortage of fossil fuels. Multi-scaled bioenergy studies have been performed in the division of Energy and Furnace Technology, which included studies of macroscopic systems such as systems and reactors, modeling of computational fluid dynamics (CFD), and atomic/molecular level studies. The present thesis focus on the atomic/molecular level that based on quantum chemistry methods.

    The microscopic structure study of biomass is the first and an important step for the investigation of the biomass thermal conversion mechanism. Cellulose, hemicellulose, and lignin are the three most important components for biomass. The atomic interactions among these three main components were studied, including the hydrogen bond linkages between cellulose and hemicellulose, and the covalent bond linkages between hemicellulose and lignin.

    The decomposition of biomass is complicated and includes cellulose decomposition, hemicellulose decomposition, and lignin decomposition. As the main component of biomass, the mechanism of cellulose pyrolysis mechanism was focused on in this thesis. The study of this mechanism included an investigation of the pathways from cellulose to levoglucosan then to lower-molecular-weight species. Three different pathways were studied for the formation of levoglucosan from cellulose, and three different pathways were studied for the levoglucosan decomposition. The thermal properties for every reactant, intermediate, and product were obtained. The kinetics parameters (rate constant, pre-exponential factor, and activation energy) for every elementary step and pathway were calculated. For the formation of levoglucosan, the levoglucosan chain-end mechanism is the favored pathway due to the lower energy barrier; for the subsequent levoglucosan decomposition process, dehydration is a preferred first step and C-C bond scission is the most difficult pathway due to the strength of the C-C bonds.

    The biomass gasification process includes pyrolysis, char gasification, and a gas-phase reaction; Char gasification is considered to be the rate-controlling step because of its slower reaction rate. Char steam gasification can be described as the adsorption of steam on the char surface to form a surface complex, which may transfer to another surface complex, which then desorbs to give the gaseous products (CO and H2) and the solid product of the remaining char. The influences of several radicals (O, H, and OH) and molecules (H2 and O2) on steam adsorption were investigated. It was concluded that the reactivity order for these particles adsorbed onto both zigzag and armchair surfaces is O > H2 > H > OH > O2. For water adsorbs on both zigzag and armchair carbon surfaces, O and OH radicals accelerate water adsorption, but H, O2, and H2 have no significant influence on water adsorption.

    It was also shown that quantum chemistry (also known as molecular modeling) can be used to investigate the reaction mechanism of a macroscopic system. Detailed atomic/molecular descriptions can provide further understanding of the reaction process and possible products.

  • 206.
    Zhang, Xiaolei
    et al.
    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.
    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.
    Formation Mechanism of Levoglucosan and Formaldehyde during Cellulose Pyrolysis2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 8, p. 3739-3746Article in journal (Refereed)
    Abstract [en]

    Biomass pyrolysis is an efficient way to transform raw biomass or organic waste materials into useable energy, including liquid, solid, and gaseous materials. Levoglucosan (1,6-anhydro-beta-D-glucopyranose) and formaldehyde are two important products in biomass pyrolysis. The formation mechanism of these two products was investigated using the density functional theory (DFT) method based on quantum mechanics. It was found that active anhydroglucose can be obtained from a cellulose homolytic reaction during high-temperature steam gasification of the biomass process. Anhydroglucose undergoes a hydrogen-donor reaction and forms an intermediate, which can transform into the products via three pathways, one (path 1) for the formation of levoglucosan and two (paths 2 and 3) for formaldehyde. A total of six elementary reactions are involved. At a pressure of 1 atm, levoglucosan can be formed at all of the temperatures (450-750 K) considered in this simulation, whereas formaldehyde can be formed only when the temperature is higher than 475 K Moreover, the energy barrier of levoglucosan formation is lower than that of formaldehyde, which is in agreement with the mechanism proposed in the experiments.

  • 207.
    Zhang, Xiaolei
    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.
    Density functional study on levoglucosan decomposition during cellulose pyrolysis2012In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Article in journal (Other academic)
  • 208.
    Zhang, Xiaolei
    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.
    Formation and Characterization of Carbon-Radical Precursors in Char Steam Gasification2010In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 24, p. 6513-6521Article in journal (Refereed)
    Abstract [en]

    Highly reactive radicals play an important role in high-temperature gasification processes. However, the effect of radicals on gasification has not been systematically investigated. In the present study, the formation of carbon-radical precursors using atomic radicals such as OH, O, and H and molecules such as H-2 and O-2 was characterized, and the effect of the precursors on the adsorption step of steam char gasification was studied using quantum chemistry methods. The results revealed that the radicals can be chemisorbed exothermically on char active sites, and the following order of reactivity was observed: O > H-2 > H > OH > O-2. Moreover, hydrogen bonds are formed between steam molecules and carbon-radical complexes. Steam molecule adsorption onto carbon-O and carbon-OH complexes is easier than adsorption onto clean carbon surfaces. Alternatively, adsorption on carbon-O-2, carbon-H-2, and carbon-H complexes is at the same level with that of clean carbon surfaces; thus, OH and O radicals accelerate the physical adsorption of steam onto the char surface, H radical and O-2 and H-2 molecules do not have a significant effect on adsorption.

  • 209.
    Zhang, Xiaolei
    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.
    Kinetics of levoglucosan and formaldehyde formation during cellulose pyrolysis process2012In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 96, no 1, p. 383-391Article in journal (Refereed)
    Abstract [en]

    The mechanisms and kinetics studies of the formation of levoglucosan and formaldehyde from anhydroglucose radical have been carried out theoretically in this paper. The geometries and frequencies of all the stationary points are calculated at the B3LYP/6-31+G(D,P) level based on quantum mechanics, Six elementary reactions are found, and three global reactions are involved. The variational transition-state rate constants for the elementary reactions are calculated within 450-1500 K. The global rate constants for every pathway are evaluated from the sum of the individual elementary reaction rate constants. The first-order Arrhenius expressions for these six elementary reactions and the three pathways are suggested. By comparing with the experimental data, computational methods without tunneling correction give good description for Path1 (the formation of levoglucosan); while methods with tunneling correction (zero-curvature tunneling and small-curvature tunneling correction) give good results for Path2 (the first possibility for the formation of formaldehyde), all the test methods give similar results for Path3 (the second possibility for the formation of formaldehyde), all the modeling results for Path3 are in good agreement with the experimental data, verifying that it is the most possible way for the formation of formaldehyde during cellulose pyrolysis.

  • 210.
    Zhang, Xiaolei
    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.
    Kinetics study on thermal dissociation of levoglucosan during cellulose pyrolysis2013In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 109, p. 476-483Article in journal (Refereed)
    Abstract [en]

    The mechanisms and kinetics studies of the levoglucosan (LG) primary decomposition during cellulose pyrolysis have been carried out theoretically in this paper. Three decomposition mechanisms (C-O bond scission, C-C bond scission, and LG dehydration) including nine pathways and 16 elementary reactions were studied at the B3LYP/6-31 + G(D, P) level based on quantum mechanics. The variational transition-state rate constants for every elementary reaction and every pathway were calculated within 298-1550 K. The first-order Arrhenius expressions for these 16 elementary reactions and nine pathways were suggested. It was concluded that computational method using transition state theory (TST) without tunneling correction gives good description for LG decomposition by comparing with the experimental result. With the temperature range of 667-1327 K, one dehydration pathway, with one water molecule composed of a hydrogen atom from C3 and a hydroxyl group from C2, is a preferred LG decomposition pathway by fitting well with the experimental results. The calculated Arrhenius plot of C-O bond scission mechanism is better agreed with the experimental Arrhenius plot than that of C-C bond scission. This C-O bond scission mechanism starts with breaking of C1-O5 and C6-O1 bonds with formation of CO molecule (C1-O1) simultaneously. C-C bond scission mechanism is the highest energetic barrier pathway for LG decomposition.

  • 211.
    Zhang, Xiaolei
    et al.
    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.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Modeling Study of Woody Biomass: Interactions of Cellulose, Hemicellulose, and Lignin2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 10, p. 4786-4795Article in journal (Refereed)
    Abstract [en]

    Lignocellulosic biomass pretreatment and the subsequent thermal conversion processes to produce solid, liquid, and gas biofuels are attractive solutions for today's energy challenges. The structural study of the main components in biomass and their macromolecular complexes is an active and ongoing research topic worldwide. The interactions among the three main components, cellulose, hemicellulose, and lignin, are studied in this paper using electronic structure methods, and the study includes examining the hydrogen bond network of cellulose-hemicellulose systems and the covalent bond linkages of hemicellulose-lignin systems. Several methods (semiempirical, Hartree-Fock, and density functional theory) using different basis sets were evaluated. It was shown that theoretical calculations can be used to simulate small model structures representing wood components. By comparing calculation results with experimental data, it was concluded that B3LYP/6-31G is the most suitable basis set to describe the hydrogen bond system and B3LYP/6-31G(d,p) is the most suitable basis set to describe the covalent system of woody biomass. The choice of unit model has a much larger effect on hydrogen bonding within cellulose-hemicellulose system, whereas the model choice has a minimal effect on the covalent linkage in the hemicellulose-lignin system.

  • 212.
    Zhang, Xiaolei
    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.
    Thermal decomposition mechanism of levoglucosan during cellulose pyrolysis2012In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 96, p. 110-119Article in journal (Refereed)
    Abstract [en]

    Levoglucosan (1,6-anhydro-beta-D-glucopyranose) decomposition is an important step during cellulose pyrolysis and for secondary tar reactions. The mechanism of levoglucosan thermal decomposition was studied in this paper using density functional theory methods. The decomposition included direct C-O bond breaking, direct C-C bond breaking, and dehydration. In total, 9 different pathways, including 16 elementary reactions, were studied, in which levoglucosan serves as a reactant. The properties of the reactants, transition states, intermediates, and products for every elementary reaction were obtained. It was found that 1-pentene-3,4-dione, acetaldehyde, 2,3-dihydroxypropanal, and propanedialdehyde can be formed from the C-O bond breaking decomposition reactions. 1,2-Dihydroxyethene and hydroxyacetic acid vinyl ester can be formed from the C C bond breaking decomposition reactions. It was concluded that C-O bond breaking is easier than C-C bond breaking due to a lower activation energy and a higher released energy. During the 6 levoglucosan dehydration pathways, one water molecule which composed of a hydrogen atom from C3 and a hydroxyl group from C2 is the preferred pathway due to a lower activation energy and higher product stability.

  • 213.
    Zhang, Xiaolei
    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.
    Dong, Changqing
    Levoglucosan Formation Mechanism during Cellulose PyrolysisArticle in journal (Other academic)
  • 214.
    Zhang, Xiaolei
    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.
    Dong, Changqing
    Levoglucosan formation mechanisms during cellulose pyrolysis2013In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 104, p. 19-27Article in journal (Refereed)
    Abstract [en]

    Levoglucosan is one important primary product during cellulose pyrolysis either as an intermediate or as a product. Three available mechanisms for levoglucosan formation have been studied theoretically in this paper, which are free-radical mechanism; glucose intermediate mechanism; and levoglucosan chain-end mechanism. All the elementary reactions included in the pathway of every mechanism were investigated; thermal properties including activation energy. Gibbs free energy, and enthalpy for every pathway were also calculated. It was concluded that free-radical mechanism has the highest energy barrier during the three levoglucosan formation mechanisms, glucose intermediate mechanism has lower energy barrier than free-radical mechanism, and levoglucosan chain-end mechanism is the most reasonable pathway because of the lowest energy barrier. By comparing with the activation energy obtained from the experimental results, it was also concluded that levoglucosan chain-end mechanism fits better with the experimental data for the formation of levoglucosan.

  • 215.
    Zhou, Chunguang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Gasification and Pyrolysis Characterization and Heat Transfer Phenomena During Thermal Conversion of Municipal Solid Waste2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The significant generation of municipal solid waste (MSW) has become a controversial global issue. Pyrolysis and gasification technologies for treating rejects from solid waste disposal sites (SWDSs), for which over 50 % of MSW is attributed to combustible species, have attracted considerable attention. MSW is an alternative energy source that can partly replace fossil resources; there is an increasing awareness that global warming caused by the utilization of fossil resources is occurring.

    The goal of this thesis is to realize the efficient and rational utilization of MSW and decrease the harmful impact of pollutants, such as dioxin, HCl, and CO2, on the environment. To achieve this goal, some fundamental studies have been experimentally and numerically conducted to enhance the understanding of the properties of municipal solid waste thermal conversion.

    In this thesis, the pyrolysis behaviors of single pelletized recovered fuel were tested. A detailed comparison of the pyrolysis behaviors of typical recovered solid waste and biomass particles was conducted. A swelling phenomenon with a swelling ratio of approximately 1.6 was observed on the surface of pelletized recovered fuels. Subsequently, a particle model was constructed to describe the thermal conversion process for large recovered fuel particles that are composed of a high fraction of polyethylene (PE) and a comparable low fraction of cardboard. The results indicate that an understanding of the heat transfer mechanism in highly porous and molten structures and the selection of a heat transfer model are crucial for accurate prediction of the conversion process.

    MSW pyrolysis is a promising method for producing liquid products. With the exception of lignocellulosic materials, such as printing paper and cardboard, PE, polystyrene (PS), polypropylene (PP), polyethylene terephthalate (PET), and polyvinyl chloride (PVC) are the six main polymers in domestic waste in Europe. Characterization studies of the products obtained from these individual components, such as PE, PET, PVC, printing paper, and cardboard, have been conducted on a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) system and a fixed-bed reactor. The possible pathways for the formation of the main primary/secondary products in rapid and conventional pyrolysis were also discussed.

    MSW steam gasification with CaO was performed in a batch-type fixed-bed gasifier to examine the effect of CaO addition on the heat transfer properties, pollutant removal, and devolatilization and char gasification behaviors in the presence of steam.

    A new carbon capture and recycle (CCR) system combined with an integrated municipal solid waste system was proposed. The foundation of the system is the development of a novel method to remediate CO2 using a high-temperature process of reforming CH4 and/or O2 and/or H2O without catalysts. Thermodynamic and experimental studies were performed. High temperatures significantly promoted the multi-reforming process while preventing the problem of catalyst deactivation. Potential improvements in the efficiency of the novel technology can be achieved by optimizing the reforming reactants. Landfill gas (LFG) and fuel gas from bio-waste treatment contain a considerable fraction of CH4, which may be a source of CH4 for this process.  

    Download full text (pdf)
    Gasification and Pyrolysis Characterization and Heat Transfer Phenomena During Thermal Conversion of Municipal Solid Waste
  • 216.
    Zhou, Chunguang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Stuermer, T.
    Gunarathne, Rathnayaka
    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 calcium oxide on high-temperature steam gasification of municipal solid waste2014In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 122, p. 36-46Article in journal (Refereed)
    Abstract [en]

    Steam gasification of municipal solid waste (MSW) using a CaO additive was investigated in a batch-type fixed bed, to examine the effects of CaO addition on the heat transfer properties, the devolatilization characteristics of MSW, CO2 adsorption capacities of CaO, and char gasification in the presence of steam. Evolutionary behaviors of syngas molar compositions and individual gas flow rates at both MSW devolatilization and char gasification stages were examined at different CaO/MSW mass ratios with a fixed MSW mass. The effect of temperature varying from 700 to 900 C was also considered in this test. In both stages, hydrogen concentrations were found to increase and CaO was found to have a catalytic effect. Finally, using from the experimental observations and the results of SEM/EDS analyses of the obtained residues, the mechanism underlying the catalytic effects of calcium species in both reaction stages was discussed.

  • 217.
    Zhou, Chunguang
    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.
    Characterization of the Products from Spruce and Pine Sawdust Pyrolysis at Various Temperatures2013In: Proceedings of the 21st EU BC&E - Copenhagen 2013, EU BC&E , 2013, p. 968-973Conference paper (Refereed)
    Abstract [en]

    Pyrolitic conversion of lignocellulosic biomass is a promising field to achieve the energy utilization and the significant reduction in CO2 emission. Both the spruce and pine are the main species in Swedish forests. During gasification process, water scrubbing system is widely adopted due to its simple and economical structure. The understanding of the releasing of tar components is quite important for the operation and gas cleaning system. Thus, pyrolysis study of spruce and pine sawdust was conducted in a batch-type reactor at 400°C, 500°C and 600°C. Yields of pyrolytic liquid, gas, and char were calculated. Pyrolytic liquids were characterized by GC-MS. Kinetic study of individual gas component was carried out. The element analysis of chars was conducted. And the energy distribution in the char, gas, and liquid, were also presented in the paper. The optimized pyrolysis conditions will achieve the oil upgrading and improve the energy utilization efficiency.

  • 218.
    Zhou, Chunguang
    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.
    Effect of heat transfer model on the prediction of municipal solid waste (MSW) pyrolysis processManuscript (preprint) (Other academic)
  • 219.
    Zhou, Chunguang
    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.
    Effect of heat transfer model on the prediction of refuse-derived fuel pyrolysis process2015In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 142, p. 46-57Article in journal (Refereed)
    Abstract [en]

    Heat transfer models using to estimate the effective thermal conductivity have been developed and included in a model for the pyrolysis of refuse-derived fuel or solid recovered fuel particles composed of cardboard and polyethylene. Both the predictions from the Kunii and Smith model and the Breitbach and Barthels model were presented and compared with the experimental data. The possible mechanisms of heat transfer in the porous solid particles were discussed. Compared to the conduction mode by solid matrix and gas phase, radiation heat flux between the neighboring voids and from particle surface and neighboring particle surface are considered as the main mechanisms at the temperatures presented in this paper. The porosity has been reported to serve as an important role in the accurate estimation of the radiation exchange factor for the radiation term in heat transfer model in a highly porous medium. Refuse-derived fuel particle with a high plastic concentration exhibits a rapid increase of porosity with the continuous thermal conversion of plastic. Thus, a coefficient as a function of porosity was applied to the radiation exchange factor in the Kunii and Smith model, which was constructed and based on a simplified model of heat transfer in packed bed. Moreover, the effect of the contact surface area between solid particles on the heat transfer of conduction mode was also considered in the Breitbach and Barthels model. Both modified models were further validated with experimental results obtained at different temperature, with different PE content and initial porosity.

  • 220.
    Zhou, Chunguang
    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.
    Characteristics of waste printing paper and cardboard in a reactor pyrolyzed by preheated agents2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 116, p. 63-71Article in journal (Refereed)
    Abstract [en]

    We studied the characteristics of waste printing paper and cardboard particles in a reactor pyrolyzed by preheated agents with the aim of simulating a real case in a fixed-bed gasifier. A TGA/DSC was first used to study of the kinetics and enthalpy change of the printing paper and cardboard pyrolysis. Pyrolitic conversion was further carried out in a batch-type reactor with non-electrical heating. Syngas, tar and char were produced and characterized from printing paper and cardboard pyrolysis at 400 degrees C, 500 degrees C and 600 degrees C. Different flow rates of carrier gas were applied to study the effect of residence time on the products distribution. When the flow rate increased, the relative mass change of gas agrees with that of tar. With increase in temperature, the yield of furfural, olefins and other non-aromatic compounds in tar decreased, while phenols and heavier aromatic hydrocarbons increased. The evolution of CO2, CO and other gas species in the syngas was presented. Van Krevelan diagram of chars was also presented in the paper.

  • 221.
    Zhou, Chunguang
    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.
    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.
    Study and development of a high temperature process of multi-reformation of CH4 with CO2 for remediation of greenhouse gas2011In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 36, no 9, p. 5450-5459Article in journal (Refereed)
    Abstract [en]

    A new carbon capture and recycle (CCR) system based on multi-reforming of CH4 with CO2 is proposed in this study. The aim was to develop a novel method to remediate greenhouse gases (CO2) using a high temperature (over 1173 K) process of reforming CH4 and/or O2, and/or H2O without catalysts. Using this novel method, the reactants are individually preheated to over 1173 K using a ceramic honeycomb heat exchanger, and then these high temperature streams enter the reactor to start the reforming reactions. Both thermodynamic and experimental studies were carried out on this novel method. Thermodynamic equilibrium models were built for four types of reforming, including dry reforming, bi-reforming, auto-thermal reforming, and tri-reforming. Only dry reforming was experimentally tested. The feasibility of this novel technology was proven by simulated and experimental results. High temperatures significantly promoted the multi-reforming process while avoiding the problem of catalyst deactivation. The experimental results on the direct system also showed that potential improvements in the efficiency of the novel technology could be achieved by optimizing the reforming reactants. Therefore, a continuous system was proposed. Moreover, the power source for the application of CCR systems was also discussed.

  • 222.
    Zhou, Chunguang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhang, Qinglin
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Arnold, Leonie
    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 study of the pyrolysis behaviors of pelletized recovered municipal solid waste fuels2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 107, p. 173-182Article in journal (Refereed)
    Abstract [en]

    Pelletized recovered solid waste fuel is often applied in gasification systems to provide feedstock with a stabilized quality and high heating value and to avoid the bridging behavior caused by high moisture content, low particle density, and irregular particle size. However, the swelling properties and the sticky material generated from pyrolysis of the plastic group components also tend to trigger bridging in the retorting zone. It is well known that the plastic group materials, which occupy a considerable proportion of municipal solid waste, can melt together easily even under low temperature. This study investigates the pyrolysis behaviors of typical recovered solid waste pellets, including the devolatilization rate, heat transfer properties, char properties, and swelling/shrinkage properties, in a small fixed-bed facility over a wide temperature range, from 900 degrees C to 450 degrees C. The results are also compared with those from wheat straw pellets, a typical cellulosic fuel. Moreover, the SEM images and BET analysis of the char structure are further analyzed to provide additional explanation for the mechanisms of swelling/shrinkage phenomena observed during heating.

  • 223.
    Zhou, Chunguang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhang, Qinglin
    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, Wlodzmierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Study of the heat transfer properties and gasification behaviors ofa single solid waste particle for Plasma Gasification Melting2012In: Proceedings of 27th International Conference on Solid Waste Technology and Management, Widener University , 2012, , p. 33Conference paper (Refereed)
    Abstract [en]

    Plasma Gasification Melting (PGM) is a promising solid waste disposal technology, which provides both environmental and energy benefits.The reaction behavior of solid waste particle has a great effect on the performance of the PGM process. In this work, an experiment study on reaction behavior of a single solid waste particle has been performed in a small high temperature air/steam gasification system under different conditions.Experiments were conducted with different gaseous agents, including N2, air,and mixture of air and steam under temperatures of 700°C, 800°C and 900°C, in order to investigate the heat transfer inside a single particle, as well as the effects of different reaction atmospheres on the reaction rates of a single wastepellet during the gasification process.

2345 201 - 223 of 223
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