The Experts below are selected from a list of 12 Experts worldwide ranked by ideXlab platform

Animesh Dutta - One of the best experts on this subject based on the ideXlab platform.

  • equilibrium modeling of gasification gibbs free energy minimization approach and its application to spouted Bed and spout Fluid Bed Gasifiers
    Energy Conversion and Management, 2008
    Co-Authors: S Jarungthammachote, Animesh Dutta
    Abstract:

    Spouted Beds have been found in many applications, one of which is gasification. In this paper, the gasification processes of conventional and modified spouted Bed Gasifiers were considered. The conventional spouted Bed is a central jet spouted Bed, while the modified spouted Beds are circular split spouted Bed and spout-Fluid Bed. The Gibbs free energy minimization method was used to predict the composition of the producer gas. The major six components, CO, CO2, CH4, H2O, H2 and N2, were determined in the mixture of the producer gas. The results showed that the carbon conversion in the gasification process plays an important role in the model. A modified model was developed by considering the carbon conversion in the constraint equations and in the energy balance calculation. The results from the modified model showed improvements. The higher heating values (HHV) were also calculated and compared with the ones from experiments. The agreements of the calculated and experimental values of HHV, especially in the case of the circular split spouted Bed and the spout-Fluid Bed were observed.

S Jarungthammachote - One of the best experts on this subject based on the ideXlab platform.

  • equilibrium modeling of gasification gibbs free energy minimization approach and its application to spouted Bed and spout Fluid Bed Gasifiers
    Energy Conversion and Management, 2008
    Co-Authors: S Jarungthammachote, Animesh Dutta
    Abstract:

    Spouted Beds have been found in many applications, one of which is gasification. In this paper, the gasification processes of conventional and modified spouted Bed Gasifiers were considered. The conventional spouted Bed is a central jet spouted Bed, while the modified spouted Beds are circular split spouted Bed and spout-Fluid Bed. The Gibbs free energy minimization method was used to predict the composition of the producer gas. The major six components, CO, CO2, CH4, H2O, H2 and N2, were determined in the mixture of the producer gas. The results showed that the carbon conversion in the gasification process plays an important role in the model. A modified model was developed by considering the carbon conversion in the constraint equations and in the energy balance calculation. The results from the modified model showed improvements. The higher heating values (HHV) were also calculated and compared with the ones from experiments. The agreements of the calculated and experimental values of HHV, especially in the case of the circular split spouted Bed and the spout-Fluid Bed were observed.

Lars Sorum - One of the best experts on this subject based on the ideXlab platform.

  • gasification of biomass to second generation biofuels a review
    Journal of Energy Resources Technology-transactions of The Asme, 2013
    Co-Authors: Berta Matas Güell, Judit Sandquist, Lars Sorum
    Abstract:

    ABSTRACT Biomass gasification has gained significant attention in the last couple of decades for the production of heat, power and second generation biofuels. Biomass gasification processes are highly complex due to the large number of reactions involved in the overall process as well as the high sensitivity of the process to changes in the operational conditions. This report reviews the state-of-the-art of biomass gasification by evaluating key process parameters such as gasifying agent, temperature, pressure, particle size, etc., for Fluidized Bed and entrained flow Gasifiers. The pros and cons of each technology and the remaining bottlenecks are also addressed. INTRODUCTION Biomass, the renewable source which stores energy in molecular carbon bond structures, is bound to play an important role in the current challenging energy scenario to provide the energy required to meet the continuous increase in energy demand and to mitigate climate change [1-2]. The large flexibility of biomass as a feedstock has been widely recognized as, besides heat and power, it can be converted into chemicals and transportation fuels. Biofuels can be used in recent infrastructures more or less directly, while other technologies, such as fuel cells and batteries, require changes in infrastructure and thus are considered as long-term solutions. Second generation biofuels can be grouped into biochemically or thermo-chemically produced, either route using non-food crops, purpose-grown perennial grasses, trees or residues. Among the different available thermo-chemical processes for the conversion of biomass to biofuels, gasification is perceived as one of the most attractive routes, as it converts feedstock very efficiently to the highest density fuels, i.e. synthetic, resulting in the most economical viable system [3]. The biomass gasification process produces synthesis gas through the chemical conversion of biomass under partial oxidation of the feedstock in reducing atmosphere in the presence of air, oxygen and/or steam [4]. The synthesis gas produced can be then converted to second generation biofuels. Various types of gasification reactor designs have been developed up to now. Fluidized Bed and entrained flow Gasifiers are currently the two main categories of gasification technologies for biofuels production. Fluid Bed Gasifiers operate below the biomass ash melting point in order to avoid Fluid Bed agglomeration and eventual collapse. This technology is attractive for its relatively low cost, ease of operation and good scale-up potential. However, it has associated relatively low energy efficiencies and poorer gas qualities; it requires intensive additional gas cleaning after the gasifier, namely tars handling and hydrocarbon reforming and is limited to small scale operations. On the other hand, entrained flow Gasifiers operate above the melting point of the biomass ashes and produce a product gas that is essentially fully converted to synthesis gas with very low contents of residual tar components, resulting in high efficiencies and higher gas quality. However, the feeding is a challenge, it has higher investment and operating costs than Fluidized Beds and therefore it is only suitable for high capacities. Thus, although substantial progress has been achieved over the last years, none of the two technologies have become commercially available and therefore a significant amount of work is still needed in this field to enable the deployment of second generation biofuels production.

Berta Matas Güell - One of the best experts on this subject based on the ideXlab platform.

  • gasification of biomass to second generation biofuels a review
    Journal of Energy Resources Technology-transactions of The Asme, 2013
    Co-Authors: Berta Matas Güell, Judit Sandquist, Lars Sorum
    Abstract:

    ABSTRACT Biomass gasification has gained significant attention in the last couple of decades for the production of heat, power and second generation biofuels. Biomass gasification processes are highly complex due to the large number of reactions involved in the overall process as well as the high sensitivity of the process to changes in the operational conditions. This report reviews the state-of-the-art of biomass gasification by evaluating key process parameters such as gasifying agent, temperature, pressure, particle size, etc., for Fluidized Bed and entrained flow Gasifiers. The pros and cons of each technology and the remaining bottlenecks are also addressed. INTRODUCTION Biomass, the renewable source which stores energy in molecular carbon bond structures, is bound to play an important role in the current challenging energy scenario to provide the energy required to meet the continuous increase in energy demand and to mitigate climate change [1-2]. The large flexibility of biomass as a feedstock has been widely recognized as, besides heat and power, it can be converted into chemicals and transportation fuels. Biofuels can be used in recent infrastructures more or less directly, while other technologies, such as fuel cells and batteries, require changes in infrastructure and thus are considered as long-term solutions. Second generation biofuels can be grouped into biochemically or thermo-chemically produced, either route using non-food crops, purpose-grown perennial grasses, trees or residues. Among the different available thermo-chemical processes for the conversion of biomass to biofuels, gasification is perceived as one of the most attractive routes, as it converts feedstock very efficiently to the highest density fuels, i.e. synthetic, resulting in the most economical viable system [3]. The biomass gasification process produces synthesis gas through the chemical conversion of biomass under partial oxidation of the feedstock in reducing atmosphere in the presence of air, oxygen and/or steam [4]. The synthesis gas produced can be then converted to second generation biofuels. Various types of gasification reactor designs have been developed up to now. Fluidized Bed and entrained flow Gasifiers are currently the two main categories of gasification technologies for biofuels production. Fluid Bed Gasifiers operate below the biomass ash melting point in order to avoid Fluid Bed agglomeration and eventual collapse. This technology is attractive for its relatively low cost, ease of operation and good scale-up potential. However, it has associated relatively low energy efficiencies and poorer gas qualities; it requires intensive additional gas cleaning after the gasifier, namely tars handling and hydrocarbon reforming and is limited to small scale operations. On the other hand, entrained flow Gasifiers operate above the melting point of the biomass ashes and produce a product gas that is essentially fully converted to synthesis gas with very low contents of residual tar components, resulting in high efficiencies and higher gas quality. However, the feeding is a challenge, it has higher investment and operating costs than Fluidized Beds and therefore it is only suitable for high capacities. Thus, although substantial progress has been achieved over the last years, none of the two technologies have become commercially available and therefore a significant amount of work is still needed in this field to enable the deployment of second generation biofuels production.

Judit Sandquist - One of the best experts on this subject based on the ideXlab platform.

  • gasification of biomass to second generation biofuels a review
    Journal of Energy Resources Technology-transactions of The Asme, 2013
    Co-Authors: Berta Matas Güell, Judit Sandquist, Lars Sorum
    Abstract:

    ABSTRACT Biomass gasification has gained significant attention in the last couple of decades for the production of heat, power and second generation biofuels. Biomass gasification processes are highly complex due to the large number of reactions involved in the overall process as well as the high sensitivity of the process to changes in the operational conditions. This report reviews the state-of-the-art of biomass gasification by evaluating key process parameters such as gasifying agent, temperature, pressure, particle size, etc., for Fluidized Bed and entrained flow Gasifiers. The pros and cons of each technology and the remaining bottlenecks are also addressed. INTRODUCTION Biomass, the renewable source which stores energy in molecular carbon bond structures, is bound to play an important role in the current challenging energy scenario to provide the energy required to meet the continuous increase in energy demand and to mitigate climate change [1-2]. The large flexibility of biomass as a feedstock has been widely recognized as, besides heat and power, it can be converted into chemicals and transportation fuels. Biofuels can be used in recent infrastructures more or less directly, while other technologies, such as fuel cells and batteries, require changes in infrastructure and thus are considered as long-term solutions. Second generation biofuels can be grouped into biochemically or thermo-chemically produced, either route using non-food crops, purpose-grown perennial grasses, trees or residues. Among the different available thermo-chemical processes for the conversion of biomass to biofuels, gasification is perceived as one of the most attractive routes, as it converts feedstock very efficiently to the highest density fuels, i.e. synthetic, resulting in the most economical viable system [3]. The biomass gasification process produces synthesis gas through the chemical conversion of biomass under partial oxidation of the feedstock in reducing atmosphere in the presence of air, oxygen and/or steam [4]. The synthesis gas produced can be then converted to second generation biofuels. Various types of gasification reactor designs have been developed up to now. Fluidized Bed and entrained flow Gasifiers are currently the two main categories of gasification technologies for biofuels production. Fluid Bed Gasifiers operate below the biomass ash melting point in order to avoid Fluid Bed agglomeration and eventual collapse. This technology is attractive for its relatively low cost, ease of operation and good scale-up potential. However, it has associated relatively low energy efficiencies and poorer gas qualities; it requires intensive additional gas cleaning after the gasifier, namely tars handling and hydrocarbon reforming and is limited to small scale operations. On the other hand, entrained flow Gasifiers operate above the melting point of the biomass ashes and produce a product gas that is essentially fully converted to synthesis gas with very low contents of residual tar components, resulting in high efficiencies and higher gas quality. However, the feeding is a challenge, it has higher investment and operating costs than Fluidized Beds and therefore it is only suitable for high capacities. Thus, although substantial progress has been achieved over the last years, none of the two technologies have become commercially available and therefore a significant amount of work is still needed in this field to enable the deployment of second generation biofuels production.