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Biocoal

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H Spliethoff – 1st expert on this subject based on the ideXlab platform

  • air blown entrained flow gasification of Biocoal gasification kinetics and char behavior
    Energy & Fuels, 2017
    Co-Authors: L Briesemeister, M Kremling, S Fendt, H Spliethoff

    Abstract:

    Air-blown entrained flow gasification of biomass has the potential of overcoming tar-related problems that occur in fixed bed or fluidized bed gasifiers. For designing entrained flow reactors (EFR), specific information on the gasification behavior of the fuel is required. Therefore, experiments with Biocoal from the hydrothermal carbonization of different feedstock (beech, biogenic residuals, municipal waste, and green waste) are performed under EFR conditions and compared to lignite. Pyrolysis chars from Biocoals and lignite are obtained in EFR at 900–1300 °C for a reactivity analysis. Intrinsic reaction rates of the char reactions with CO2, H2O and O2 are measured in a thermogravimetric analyzer. Compared to lignite, chars from Biocoal are less reactive due to smaller surface areas and less catalytic ash constituents. Char samples from gasification with varying air-to-fuel equivalence ratios, λ, and residence times are sampled from an autothermal gasifier and from a laboratory-scale EFR at 900–1300 °C….

  • air blown entrained flow gasification of Biocoal from hydrothermal carbonization
    Chemical Engineering & Technology, 2017
    Co-Authors: L Briesemeister, M Kremling, S Fendt, H Spliethoff

    Abstract:

    Hydrothermal carbonization was used to convert green waste into a high-quality Biocoal that was applied to an air-blown entrained-flow gasifier. Fuel-specific operating parameters are required to achieve complete fuel conversion and operate the gasifier at high efficiency. Therefore, different air-to-fuel equivalence ratios and steam addition were applied to investigate effects on gasifier performance. Fuel and carbon conversion were determined by char-particle analysis. The syngas composition and cold gas efficiencies were determined and the solid-phase adsorption method was used for tar measurements. It was shown that owing to high conversion rates and comparably low tar loading, Biocoal is very applicable for entrained-flow gasification. Higher gas preheating temperatures would improve the process.

  • entrained flow gasification of Biocoal from hydrothermal carbonization
    Fuel, 2012
    Co-Authors: Alexander Tremel, Berit Erlach, Jan Stemann, Michael Herrmann, H Spliethoff

    Abstract:

    Abstract Hydrothermal carbonization (HTC) converts biomass into a coal-like substance, here referred to as Biocoal. Beech wood chips are treated hydrothermally at 210 °C for 3 h in a 250 L pilot scale reactor. The carbon content (daf) thereby increases from 48 wt.% to 57 wt.% and the volatile matter (wf) decreases from 79 wt.% to 69 wt.%. The carbon and energy yields are both 80% on a mass and HHV basis, respectively, with the major loss being solubilized substances. Pulverization of Biocoal is found to be much less energy intensive compared to wood. Moreover, pulverized particles show a spherical shape which may facilitate fluidization. Gasification experiments are carried out at temperatures of 1000 °C, 1200 °C and 1400 °C at atmospheric pressure in a laboratory scale entrained flow reactor. The standard particle diameter used in the experiments is 80–160 μm. During each experiment char samples are collected and the synthesis gas concentration is measured. Carbon conversion at a residence time of 1.0 s is 84%, at both 1000 °C and 1200 °C. A significant increase in carbon conversion to 88% at 1400 °C is observed. Comparable gasification experiments are carried out with lignite as the fuel. Rhenish lignite is gasified using the same stoichiometry and particle size. The conversion of lignite is slightly lower indicating the high reactivity of Biocoal. An increase of particle size would be beneficial due to the lower power consumption for pulverization. In experiments with Biocoal at a particle size of 160–250 μm, a slightly lower conversion is measured due to internal and external mass transfer limitations at the particles. The high conversion at short reaction times indicates a high reactivity of Biocoal under entrained flow gasification conditions.

L Briesemeister – 2nd expert on this subject based on the ideXlab platform

  • Air-Blown Entrained Flow Gasification of Biomass: Influence of Operating Conditions on Tar Generation
    Energy & Fuels, 2017
    Co-Authors: L Briesemeister, M Kremling, Sebastian Fendt, Hartmut Spliethoff

    Abstract:

    The formation of tars in gasifiers based on fluidized- or fixed-bed technology is a major problem in biomass gasification. By pretreating biomass using hydrothermal carbonization (HTC), entrained-flow gasification becomes applicable. Oxygen-blown entrained-flow gasifiers (EFGs) operate at very high process temperatures, leading to an almost tar-free syngas. However, in decentralized small-scale units, preferably air is used as the gasification agent, which, in turn, causes lower gasifier temperatures. The specific impacts of air-blown gasification conditions and fuel properties of Biocoal from HTC on tar formation require particular attention. Therefore, in this work, tar formation under air-blown gasification conditions is investigated using solid-phase adsorption at an electrically heated EFG with temperatures of 900–1300 °C and different air/fuel equivalence ratios λ. Furthermore, tars are measured in the hot syngas of an industrial-like autothermal EFG. HTC Biocoals of various feedstocks (beech, bioge…

  • air blown entrained flow gasification of Biocoal gasification kinetics and char behavior
    Energy & Fuels, 2017
    Co-Authors: L Briesemeister, M Kremling, S Fendt, H Spliethoff

    Abstract:

    Air-blown entrained flow gasification of biomass has the potential of overcoming tar-related problems that occur in fixed bed or fluidized bed gasifiers. For designing entrained flow reactors (EFR), specific information on the gasification behavior of the fuel is required. Therefore, experiments with Biocoal from the hydrothermal carbonization of different feedstock (beech, biogenic residuals, municipal waste, and green waste) are performed under EFR conditions and compared to lignite. Pyrolysis chars from Biocoals and lignite are obtained in EFR at 900–1300 °C for a reactivity analysis. Intrinsic reaction rates of the char reactions with CO2, H2O and O2 are measured in a thermogravimetric analyzer. Compared to lignite, chars from Biocoal are less reactive due to smaller surface areas and less catalytic ash constituents. Char samples from gasification with varying air-to-fuel equivalence ratios, λ, and residence times are sampled from an autothermal gasifier and from a laboratory-scale EFR at 900–1300 °C….

  • air blown entrained flow gasification of Biocoal from hydrothermal carbonization
    Chemical Engineering & Technology, 2017
    Co-Authors: L Briesemeister, M Kremling, S Fendt, H Spliethoff

    Abstract:

    Hydrothermal carbonization was used to convert green waste into a high-quality Biocoal that was applied to an air-blown entrained-flow gasifier. Fuel-specific operating parameters are required to achieve complete fuel conversion and operate the gasifier at high efficiency. Therefore, different air-to-fuel equivalence ratios and steam addition were applied to investigate effects on gasifier performance. Fuel and carbon conversion were determined by char-particle analysis. The syngas composition and cold gas efficiencies were determined and the solid-phase adsorption method was used for tar measurements. It was shown that owing to high conversion rates and comparably low tar loading, Biocoal is very applicable for entrained-flow gasification. Higher gas preheating temperatures would improve the process.

Hartmut Spliethoff – 3rd expert on this subject based on the ideXlab platform

  • Air-Blown Entrained Flow Gasification of Biomass: Influence of Operating Conditions on Tar Generation
    Energy & Fuels, 2017
    Co-Authors: L Briesemeister, M Kremling, Sebastian Fendt, Hartmut Spliethoff

    Abstract:

    The formation of tars in gasifiers based on fluidized- or fixed-bed technology is a major problem in biomass gasification. By pretreating biomass using hydrothermal carbonization (HTC), entrained-flow gasification becomes applicable. Oxygen-blown entrained-flow gasifiers (EFGs) operate at very high process temperatures, leading to an almost tar-free syngas. However, in decentralized small-scale units, preferably air is used as the gasification agent, which, in turn, causes lower gasifier temperatures. The specific impacts of air-blown gasification conditions and fuel properties of Biocoal from HTC on tar formation require particular attention. Therefore, in this work, tar formation under air-blown gasification conditions is investigated using solid-phase adsorption at an electrically heated EFG with temperatures of 900–1300 °C and different air/fuel equivalence ratios λ. Furthermore, tars are measured in the hot syngas of an industrial-like autothermal EFG. HTC Biocoals of various feedstocks (beech, bioge…

  • Study of a decentralized entrained-flow gasification plant in combination with biomass from hydrothermal carbonization for chp
    , 2014
    Co-Authors: L Briesemeister, T. Wittmann, Matthias Gaderer, Hartmut Spliethoff

    Abstract:

    In this paper a new approach, consisting of hydrothermal carbonization in combination with gasification in an entrained-flow process for combined heat and power in a gas engine is investigated. Main advantage of such a system are the low consumption costs resulting from the type of applicable feeding materials that are not usable with state of the art technologies. In the first part a highly integrated plant for the production of Biocoal with hydrothermal carbonization is investigated with a plant size of 16 MW of Biocoal production. The process is modeled in Aspen Plus® in order to determine energy and material flows as well as to optimize the heat integration of the system. The decentralized utilization of Biocoal from hydrothermal carbonization in an entrained-flow gasifier is simulated for a plant size of 1.6 MW Biocoal input. Efficiencies of the heat and power generation are calculated for individual components and the whole process chain. Power can be produced with an overall electric efficiency of 26 %.

  • Entrained flow gasification of Biocoal from hydrothermal carbonization
    Fuel, 2012
    Co-Authors: Alexander Tremel, Berit Erlach, Jan Stemann, Michael Herrmann, Hartmut Spliethoff

    Abstract:

    Hydrothermal carbonization (HTC) converts biomass into a coal-like substance, here referred to as Biocoal. Beech wood chips are treated hydrothermally at 210 °C for 3 h in a 250 L pilot scale reactor. The carbon content (daf) thereby increases from 48 wt.% to 57 wt.% and the volatile matter (wf) decreases from 79 wt.% to 69 wt.%. The carbon and energy yields are both 80% on a mass and HHV basis, respectively, with the major loss being solubilized substances. Pulverization of Biocoal is found to be much less energy intensive compared to wood. Moreover, pulverized particles show a spherical shape which may facilitate fluidization. Gasification experiments are carried out at temperatures of 1000 °C, 1200 °C and 1400 °C at atmospheric pressure in a laboratory scale entrained flow reactor. The standard particle diameter used in the experiments is 80-160 μm. During each experiment char samples are collected and the synthesis gas concentration is measured. Carbon conversion at a residence time of 1.0 s is 84%, at both 1000 °C and 1200 °C. A significant increase in carbon conversion to 88% at 1400 °C is observed. Comparable gasification experiments are carried out with lignite as the fuel. Rhenish lignite is gasified using the same stoichiometry and particle size. The conversion of lignite is slightly lower indicating the high reactivity of Biocoal. An increase of particle size would be beneficial due to the lower power consumption for pulverization. In experiments with Biocoal at a particle size of 160-250 μm, a slightly lower conversion is measured due to internal and external mass transfer limitations at the particles. The high conversion at short reaction times indicates a high reactivity of Biocoal under entrained flow gasification conditions. © 2012 Elsevier Ltd. All rights reserved.