The Experts below are selected from a list of 147 Experts worldwide ranked by ideXlab platform

Steffen Heidenreich - One of the best experts on this subject based on the ideXlab platform.

  • Syngas conditioning by ceramic Filter Candles filled with catalyst pellets and placed inside the freeboard of a fluidized bed steam gasifier
    Fuel Processing Technology, 2019
    Co-Authors: Elisa Savuto, Katia Gallucci, Steffen Heidenreich, Andrea Di Carlo, Andrew Steele, Sergio Rapagna
    Abstract:

    Abstract Gasification is a very advantageous conversion process to obtain a fuel gas from organic wastes, however it also generates by-products, such as particulate and tar. These should be removed from the syngas for its smooth utilization in power generation devices and/or biofuels production. In this work, biomass gasification tests were carried out in a bench-scale fluidized bed gasifier with a ceramic Filter Candle filled with commercial Ni-catalyst pellets integrated in its freeboard, for the abatement of particulate and tar. The activity of catalyst was studied at different operating conditions (temperature and catalyst bed layout) and the results were analysed in terms of residual tar content and composition of the product gas. The catalyst resulted very effective, particularly in tests at higher temperature and with the partially filled Candle configuration. Tars were reduced to 250 mg/Nm3 in the best case. The Ni-catalyst did not show deactivation during tests lasting 4 h.

  • tar abatement in a fixed bed catalytic Filter Candle during biomass gasification in a dual fluidized bed
    Applied Catalysis B-environmental, 2016
    Co-Authors: F Garcialabiano, Manfred Nacken, P Gayan, L F De Diego, Alberto Abad, T Mendiara, Juan Adanez, Steffen Heidenreich
    Abstract:

    Abstract Catalytic Filters are a novel technology for tar conversion in biomass gasification processes. Both particle elimination and tar abatement can be achieved in a single step at high temperatures minimizing energy efficiency penalties. This paper analyses the performance of a fixed bed catalytic Filter Candle in the reduction of biomass tar generated in situ in a dual fluidized bed gasifier (DFBG). In this study, the temperature of the Filter was limited to 800 °C. Several variables affecting the performance of the Filter were tested. Experiments at different gasification temperatures in the range 750–850 °C were performed so that the amount of tar reaching the catalytic Filter was varied. The amount of tar at the catalytic Filter inlet did not affect the tar conversion achieved which was around 75%. The major tar compound in the gasification gas at the outlet of the catalytic Filter was naphthalene. At the highest temperature tested (850 °C), the tar content in the clean gas was 0.65 g/Nm3. The effect of the face velocity in the Filter on the tar conversion reached was evaluated. Tar conversion decreased when the face velocity increased from 40 to 90 m/h as the residence time of the gas in the catalytic Filter was lower. The ratio H2O to dry biomass was also varied (0.5–0.9) in order to produce tars of different nature. Higher conversions were achieved for higher values of this ratio.

  • Gas conditioning in H2 rich syngas production by biomass steam gasification: Experimental comparison between three innovative ceramic Filter Candles
    International Journal of Hydrogen Energy, 2015
    Co-Authors: A. D'orazio, Sergio Rapagna, Katia Gallucci, Manfred Nacken, Steffen Heidenreich, P.u. Foscolo, A. Di Carlo, Alessandro Dell’era
    Abstract:

    Abstract The biomass steam gasification is a promising path to obtain hydrogen-rich syngas and to improve the global efficiency for cogeneration purposes. The present study reports the results of a campaign of steam gasification tests performed in a bench-scale gasifier (0.1 m ID) housing in its freeboard a ceramic Filter, in a temperature range of 800 °C–815 °C. Three new ceramic Filters have been tested: (i) noncatalytic Candle with new support, (ii) Filter Candle with catalytic layer, (iii) Filter Candle with new integrated catalytic foam system and results were compared to those obtained in tests without Candle. The volume composition of the syngas was monitored and analyzed by online measurement by means of infrared – thermal conductivity detector (IR-TCD) facilities to evaluate the CO, CO2, CH4, H2, NH3 composition. The Topping Atmosphere Residue (tar) content was evaluated by gas-chromatograph mass spectrometer (GCMS) facility; gas yield, water conversion and char conversion were also calculated from direct measurements. The best results were obtained in the case of innovative catalytic Filter in association with cycled olivine bed, obtaining gas yield equal to 1.80 Nm3/kgdaf (vs 1.00 Nm3/kgdaf without Candle); observed to theoretical water conversion ratio equal to 0.88 (vs 0.33); H2 volume content equal to 56% (vs 39%); total tar content equal to 0.14 g/Nm3 (vs 6 g/Nm3).

  • New DeTar catalytic Filter with integrated catalytic ceramic foam: Catalytic activity under model and real bio syngas conditions
    Fuel Processing Technology, 2015
    Co-Authors: Manfred Nacken, Sergio Rapagna, Katia Gallucci, Steffen Heidenreich, Gino V. Baron, A. D'orazio, Joeri F. M. Denayer, Pier Ugo Foscolo
    Abstract:

    Abstract The catalytic activity of a new catalytic Filter of combined design consisting of a catalytic Filter Candle with an integrated catalytic ceramic foam was calculated under model gas conditions at 800 and 850 °C in the absence and presence of 100 ppmv H 2 S on the basis of separate and combined measurements of appropriate catalytic Filter element and ceramic foam disk samples. Real gas validation of the determined model gas activity of the catalytic Filter of combined design in a bench-scale gasifier was performed to check-up, if model gas conversions can be used as bases for the prediction of real tar conversions. A calculation of the model gas activity of the catalytic Filter at a superficial velocity of 2 cm/s based on the disk measurements results to 99% naphthalene conversion at 850 °C in the absence of H 2 S and 94% in the presence of 100 ppmv H 2 S. At 800 °C, the calculated conversion is 95% in the absence and 70% in the presence of 100 ppmv H 2 S resulting in an estimated conversion of 85% at an H 2 S content of 40 ppmv. This value is comparable with the measured real tar conversion of 81% at 790 °C and a superficial velocity of 2.5 cm/s.

  • Development of a catalytic ceramic foam for efficient tar reforming of a catalytic Filter for hot gas cleaning of biomass-derived syngas
    Applied Catalysis B-environmental, 2012
    Co-Authors: Manfred Nacken, Steffen Heidenreich, Lina Ma, Francis Verpoort, Gino V. Baron
    Abstract:

    Abstract In order to improve the tar reforming performance of a catalytic Filter in hot gas cleaning of biomass-derived syngas, as new approach, 45 ppi ceramic foams of 10 mm wall thickness were used as ceramic support for catalyst integration. Screening of this ceramic support was performed by varying the type of catalyst support, its loading and the NiO loading. As a result, a SiC ceramic foam with a MgO-Al2O3-NiO catalytic layer, a catalyst support density of 0.03 g/cm3 and a NiO density of 0.02 g/cm3 was identified as most active catalytic ceramic foam. After the transfer of the corresponding impregnation procedure to an Al2O3 based ceramic foam to be able to operate at the target filtration temperature of 850 °C, a naphthalene conversion of 99% was achieved at a superficial velocity of 2.5 cm/s in the presence of 100 ppmv H2S. At doubled superficial velocity the conversion still achieves 93%. The transfer of the catalyst integration procedure for the most active SiC Candle supported MgO-Al2O3-NiO layer to an Al2O3 Filter Candle with 10 mm wall thickness has led to a naphthalene conversion of 87% at 850 °C at a superficial velocity of 2 cm/s in the presence of 100 ppmv H2S being 8% higher than in the SiC based Candle. The combined Al2O3 based catalytic Filter and ceramic foam disk system shows an overall conversion of 99% at a superficial velocity of 2 cm/s. Based on these results the corresponding overall conversion of an Al2O3 based catalytic Filter Candle with integrated catalytic ceramic foam was precalculated to 98% at 850 °C in the presence of 100 ppmv H2S indicating the technical feasibility of efficient tar reforming using this novel catalytic Filter Candle design.

Joohong Choi - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of Nozzle Design for Pulse Cleaning of Ceramic Filter
    Chinese Journal of Chemical Engineering, 2008
    Co-Authors: Liang Yu, Joohong Choi, Zhongli Ji
    Abstract:

    Abstract The experimental study was carried out to optimize the nozzle shape and dimension for the pulse cleaning of a ceramic Filter Candle. A bench scale unit of ceramic Filter consisting of four commercial Filter elements was used to measure the traces of the transient pressure around the nozzle and the overpressure in the Filter cavity during the pulse-jet injection of pulse gas. Overpressure in the Filter cavity is related to the pulse cleaning force. Nozzle design is concerned to increase the overpressure at the open end of Filter element of pulse cleaning inlet, as well as to minimize the consumption of pulse gas. Convergent nozzle induces more secondary flow and generates higher pulse cleaning effect than straight nozzle. Nozzles of different convergent ratio (ratio of outlet to inlet diameter of nozzle) by changing the convergent angle and height were tested. The outlet diameter of convergent nozzle seriously influences the cleaning effect. The optimum convergent ratio increases with the increase of pulse gas pressure. The nozzle position (distance of nozzle tip from the open end of Filter inlet) is also important to decide the nozzle dimension. Nozzle of large outlet diameter accepts high pressure of pulse gas to provide large overpressure in the Filter cavity of top position by applying long distance.

  • The reactivity of V_2O_5-WO_3-TiO_2 catalyst supported on a ceramic Filter Candle for selective reduction of NO
    Korean Journal of Chemical Engineering, 2001
    Co-Authors: Joohong Choi
    Abstract:

    For realizing the environmental issues and constituting an economical treatment system, a catalytic Filter based on V_2O_5/TiO_2 supported on tubular Filter elements has many advantages by removing NO_x and particulate simultaneously from flue gas. In order to improve the activity of a catalytic Filter based on V_2O_5/TiO_2 supported on a commercial high temperature Filter element (PRD-66), the promoting effects of WO_3 were investigated in an experimental unit. PRD-66 presented very good properties for SCR catalyst carrier since it contains much active material such as A1_2O_3 SiO{om2}, and MgO whose contributions were remarkable. For additional catalyst carrier, TiO_2 particles were coated in the pores of PRD-66 with relatively good distribution of the particle size less than 1 μm, by a coating process applying centrifugal force. WO_3, in the V_2O_5-WO_3-TiO_2/PRD-66 catalytic Filter system, increased the SCR activity significantly and broadened the optimum temperature window. The catalytic Filter shows the maximum NO conversion of more than 95% for NO concentration of 700 ppmv at face velocity of 0.02 m/sec, which is comparable to the current commercial catalytic Filters of plate form.

  • the reactivity of v2o5 wo3 tio2 catalyst supported on a ceramic Filter Candle for selective reduction of no
    Korean Journal of Chemical Engineering, 2001
    Co-Authors: Joohong Choi
    Abstract:

    For realizing the environmental issues and constituting an economical treatment system, a catalytic Filter based on V2O5/TiO2 supported on tubular Filter elements has many advantages by removing NOx and particulate simultaneously from flue gas. In order to improve the activity of a catalytic Filter based on V2O5/TiO2 supported on a commercial high temperature Filter element (PRD-66), the promoting effects of WO3 were investigated in an experimental unit. PRD-66 presented very good properties for SCR catalyst carrier since it contains much active material such as A12O3 SiO{om2}, and MgO whose contributions were remarkable. For additional catalyst carrier, TiO2 particles were coated in the pores of PRD-66 with relatively good distribution of the particle size less than 1 μm, by a coating process applying centrifugal force. WO3, in the V2O5-WO3-TiO2/PRD-66 catalytic Filter system, increased the SCR activity significantly and broadened the optimum temperature window. The catalytic Filter shows the maximum NO conversion of more than 95% for NO concentration of 700 ppmv at face velocity of 0.02 m/sec, which is comparable to the current commercial catalytic Filters of plate form.

  • The preparation of V_2O_5/TiO_2 catalyst supported on the ceramic Filter Candle for selective reduction of NO
    Korean Journal of Chemical Engineering, 2001
    Co-Authors: Joohong Choi, Sun-jong Ha, Young-ok Park
    Abstract:

    In order to prepare the catalytic Filters based on V_2O_5/TiO_2 for the removal of NO_x and participate simultaneously from the flue gas stream, the experimental study was carried out. The effective method to support TiO_2 layer in the pore of the commercial ceramic Filter element was developed. TiO_2 layer was supported on the Filter element by three methods; impregnation with Ti solution, sol-gel dip coating and sol-gel centrifugal coating. As the model test to check the catalytic activity, NO reduction in the oxidizing stream was investigated. The catalytic Filter prepared by applying the centrifugal force showed the best NO conversion more than 90% when the face velocity was 0.02 m/sec. This was a very promising result for the application of catalytic Filter for the flue gas control at high temperature. The supporting methods by the impregnation and dip coating were not recommended because the TiO_2 layer was concentrated in the exterior layer of the Filter element.

  • the preparation of v2o5 tio2 catalyst supported on the ceramic Filter Candle for selective reduction of no
    Korean Journal of Chemical Engineering, 2001
    Co-Authors: Joohong Choi, Sun-jong Ha, Young-ok Park
    Abstract:

    In order to prepare the catalytic Filters based on V2O5/TiO2 for the removal of NOx and participate simultaneously from the flue gas stream, the experimental study was carried out. The effective method to support TiO2 layer in the pore of the commercial ceramic Filter element was developed. TiO2 layer was supported on the Filter element by three methods; impregnation with Ti solution, sol-gel dip coating and sol-gel centrifugal coating. As the model test to check the catalytic activity, NO reduction in the oxidizing stream was investigated. The catalytic Filter prepared by applying the centrifugal force showed the best NO conversion more than 90% when the face velocity was 0.02 m/sec. This was a very promising result for the application of catalytic Filter for the flue gas control at high temperature. The supporting methods by the impregnation and dip coating were not recommended because the TiO2 layer was concentrated in the exterior layer of the Filter element.

Manfred Nacken - One of the best experts on this subject based on the ideXlab platform.

  • tar abatement in a fixed bed catalytic Filter Candle during biomass gasification in a dual fluidized bed
    Applied Catalysis B-environmental, 2016
    Co-Authors: F Garcialabiano, Manfred Nacken, P Gayan, L F De Diego, Alberto Abad, T Mendiara, Juan Adanez, Steffen Heidenreich
    Abstract:

    Abstract Catalytic Filters are a novel technology for tar conversion in biomass gasification processes. Both particle elimination and tar abatement can be achieved in a single step at high temperatures minimizing energy efficiency penalties. This paper analyses the performance of a fixed bed catalytic Filter Candle in the reduction of biomass tar generated in situ in a dual fluidized bed gasifier (DFBG). In this study, the temperature of the Filter was limited to 800 °C. Several variables affecting the performance of the Filter were tested. Experiments at different gasification temperatures in the range 750–850 °C were performed so that the amount of tar reaching the catalytic Filter was varied. The amount of tar at the catalytic Filter inlet did not affect the tar conversion achieved which was around 75%. The major tar compound in the gasification gas at the outlet of the catalytic Filter was naphthalene. At the highest temperature tested (850 °C), the tar content in the clean gas was 0.65 g/Nm3. The effect of the face velocity in the Filter on the tar conversion reached was evaluated. Tar conversion decreased when the face velocity increased from 40 to 90 m/h as the residence time of the gas in the catalytic Filter was lower. The ratio H2O to dry biomass was also varied (0.5–0.9) in order to produce tars of different nature. Higher conversions were achieved for higher values of this ratio.

  • Gas conditioning in H2 rich syngas production by biomass steam gasification: Experimental comparison between three innovative ceramic Filter Candles
    International Journal of Hydrogen Energy, 2015
    Co-Authors: A. D'orazio, Sergio Rapagna, Katia Gallucci, Manfred Nacken, Steffen Heidenreich, P.u. Foscolo, A. Di Carlo, Alessandro Dell’era
    Abstract:

    Abstract The biomass steam gasification is a promising path to obtain hydrogen-rich syngas and to improve the global efficiency for cogeneration purposes. The present study reports the results of a campaign of steam gasification tests performed in a bench-scale gasifier (0.1 m ID) housing in its freeboard a ceramic Filter, in a temperature range of 800 °C–815 °C. Three new ceramic Filters have been tested: (i) noncatalytic Candle with new support, (ii) Filter Candle with catalytic layer, (iii) Filter Candle with new integrated catalytic foam system and results were compared to those obtained in tests without Candle. The volume composition of the syngas was monitored and analyzed by online measurement by means of infrared – thermal conductivity detector (IR-TCD) facilities to evaluate the CO, CO2, CH4, H2, NH3 composition. The Topping Atmosphere Residue (tar) content was evaluated by gas-chromatograph mass spectrometer (GCMS) facility; gas yield, water conversion and char conversion were also calculated from direct measurements. The best results were obtained in the case of innovative catalytic Filter in association with cycled olivine bed, obtaining gas yield equal to 1.80 Nm3/kgdaf (vs 1.00 Nm3/kgdaf without Candle); observed to theoretical water conversion ratio equal to 0.88 (vs 0.33); H2 volume content equal to 56% (vs 39%); total tar content equal to 0.14 g/Nm3 (vs 6 g/Nm3).

  • New DeTar catalytic Filter with integrated catalytic ceramic foam: Catalytic activity under model and real bio syngas conditions
    Fuel Processing Technology, 2015
    Co-Authors: Manfred Nacken, Sergio Rapagna, Katia Gallucci, Steffen Heidenreich, Gino V. Baron, A. D'orazio, Joeri F. M. Denayer, Pier Ugo Foscolo
    Abstract:

    Abstract The catalytic activity of a new catalytic Filter of combined design consisting of a catalytic Filter Candle with an integrated catalytic ceramic foam was calculated under model gas conditions at 800 and 850 °C in the absence and presence of 100 ppmv H 2 S on the basis of separate and combined measurements of appropriate catalytic Filter element and ceramic foam disk samples. Real gas validation of the determined model gas activity of the catalytic Filter of combined design in a bench-scale gasifier was performed to check-up, if model gas conversions can be used as bases for the prediction of real tar conversions. A calculation of the model gas activity of the catalytic Filter at a superficial velocity of 2 cm/s based on the disk measurements results to 99% naphthalene conversion at 850 °C in the absence of H 2 S and 94% in the presence of 100 ppmv H 2 S. At 800 °C, the calculated conversion is 95% in the absence and 70% in the presence of 100 ppmv H 2 S resulting in an estimated conversion of 85% at an H 2 S content of 40 ppmv. This value is comparable with the measured real tar conversion of 81% at 790 °C and a superficial velocity of 2.5 cm/s.

  • Development of a catalytic ceramic foam for efficient tar reforming of a catalytic Filter for hot gas cleaning of biomass-derived syngas
    Applied Catalysis B-environmental, 2012
    Co-Authors: Manfred Nacken, Steffen Heidenreich, Lina Ma, Francis Verpoort, Gino V. Baron
    Abstract:

    Abstract In order to improve the tar reforming performance of a catalytic Filter in hot gas cleaning of biomass-derived syngas, as new approach, 45 ppi ceramic foams of 10 mm wall thickness were used as ceramic support for catalyst integration. Screening of this ceramic support was performed by varying the type of catalyst support, its loading and the NiO loading. As a result, a SiC ceramic foam with a MgO-Al2O3-NiO catalytic layer, a catalyst support density of 0.03 g/cm3 and a NiO density of 0.02 g/cm3 was identified as most active catalytic ceramic foam. After the transfer of the corresponding impregnation procedure to an Al2O3 based ceramic foam to be able to operate at the target filtration temperature of 850 °C, a naphthalene conversion of 99% was achieved at a superficial velocity of 2.5 cm/s in the presence of 100 ppmv H2S. At doubled superficial velocity the conversion still achieves 93%. The transfer of the catalyst integration procedure for the most active SiC Candle supported MgO-Al2O3-NiO layer to an Al2O3 Filter Candle with 10 mm wall thickness has led to a naphthalene conversion of 87% at 850 °C at a superficial velocity of 2 cm/s in the presence of 100 ppmv H2S being 8% higher than in the SiC based Candle. The combined Al2O3 based catalytic Filter and ceramic foam disk system shows an overall conversion of 99% at a superficial velocity of 2 cm/s. Based on these results the corresponding overall conversion of an Al2O3 based catalytic Filter Candle with integrated catalytic ceramic foam was precalculated to 98% at 850 °C in the presence of 100 ppmv H2S indicating the technical feasibility of efficient tar reforming using this novel catalytic Filter Candle design.

  • First Al2O3 based catalytic Filter Candles operating in the fluidized bed gasifier freeboard
    Fuel, 2012
    Co-Authors: Sergio Rapagna, Katia Gallucci, Manuela Di Marcello, Manfred Nacken, Steffen Heidenreich, Pier Ugo Foscolo, Muriel Matt
    Abstract:

    Abstract Al 2 O 3 based grain-sintered Filter element support was first impregnated with a fine, wet-milled suspension of a MgO–Al 2 O 3 and successively with nickel nitrate hexahydrate. The catalytic Filter Candle was inserted in the freeboard of a 0.1 m I.D. fluidized bed biomass gasifier, in order to obtain a very compact gasification and hot gas cleaning unit. Continuous catalytic steam gasification runs of almond shells have been performed in a temperature range of 808–813 °C (maintained by means of an electric furnace), and the volume composition of the product gas has been analyzed by means of IR, UV and TCD facilities for online detection of CO, CO 2 , CH 4 , H 2 , NH 3 and H 2 S. A 20 h test has been performed with intermediate char burning steps. The measured gas yield was 2.09 Nm 3 /kg daf , meanwhile the gas composition in % by volume was H 2  = 56, CO = 22, CO 2  = 20, and CH 4  = 2. NH 3 and H 2 S in the dry gas were 60–80 ppmv and 10–15 ppmv, respectively.

Sergio Rapagna - One of the best experts on this subject based on the ideXlab platform.

  • Syngas conditioning by ceramic Filter Candles filled with catalyst pellets and placed inside the freeboard of a fluidized bed steam gasifier
    Fuel Processing Technology, 2019
    Co-Authors: Elisa Savuto, Katia Gallucci, Steffen Heidenreich, Andrea Di Carlo, Andrew Steele, Sergio Rapagna
    Abstract:

    Abstract Gasification is a very advantageous conversion process to obtain a fuel gas from organic wastes, however it also generates by-products, such as particulate and tar. These should be removed from the syngas for its smooth utilization in power generation devices and/or biofuels production. In this work, biomass gasification tests were carried out in a bench-scale fluidized bed gasifier with a ceramic Filter Candle filled with commercial Ni-catalyst pellets integrated in its freeboard, for the abatement of particulate and tar. The activity of catalyst was studied at different operating conditions (temperature and catalyst bed layout) and the results were analysed in terms of residual tar content and composition of the product gas. The catalyst resulted very effective, particularly in tests at higher temperature and with the partially filled Candle configuration. Tars were reduced to 250 mg/Nm3 in the best case. The Ni-catalyst did not show deactivation during tests lasting 4 h.

  • Gas conditioning in H2 rich syngas production by biomass steam gasification: Experimental comparison between three innovative ceramic Filter Candles
    International Journal of Hydrogen Energy, 2015
    Co-Authors: A. D'orazio, Sergio Rapagna, Katia Gallucci, Manfred Nacken, Steffen Heidenreich, P.u. Foscolo, A. Di Carlo, Alessandro Dell’era
    Abstract:

    Abstract The biomass steam gasification is a promising path to obtain hydrogen-rich syngas and to improve the global efficiency for cogeneration purposes. The present study reports the results of a campaign of steam gasification tests performed in a bench-scale gasifier (0.1 m ID) housing in its freeboard a ceramic Filter, in a temperature range of 800 °C–815 °C. Three new ceramic Filters have been tested: (i) noncatalytic Candle with new support, (ii) Filter Candle with catalytic layer, (iii) Filter Candle with new integrated catalytic foam system and results were compared to those obtained in tests without Candle. The volume composition of the syngas was monitored and analyzed by online measurement by means of infrared – thermal conductivity detector (IR-TCD) facilities to evaluate the CO, CO2, CH4, H2, NH3 composition. The Topping Atmosphere Residue (tar) content was evaluated by gas-chromatograph mass spectrometer (GCMS) facility; gas yield, water conversion and char conversion were also calculated from direct measurements. The best results were obtained in the case of innovative catalytic Filter in association with cycled olivine bed, obtaining gas yield equal to 1.80 Nm3/kgdaf (vs 1.00 Nm3/kgdaf without Candle); observed to theoretical water conversion ratio equal to 0.88 (vs 0.33); H2 volume content equal to 56% (vs 39%); total tar content equal to 0.14 g/Nm3 (vs 6 g/Nm3).

  • New DeTar catalytic Filter with integrated catalytic ceramic foam: Catalytic activity under model and real bio syngas conditions
    Fuel Processing Technology, 2015
    Co-Authors: Manfred Nacken, Sergio Rapagna, Katia Gallucci, Steffen Heidenreich, Gino V. Baron, A. D'orazio, Joeri F. M. Denayer, Pier Ugo Foscolo
    Abstract:

    Abstract The catalytic activity of a new catalytic Filter of combined design consisting of a catalytic Filter Candle with an integrated catalytic ceramic foam was calculated under model gas conditions at 800 and 850 °C in the absence and presence of 100 ppmv H 2 S on the basis of separate and combined measurements of appropriate catalytic Filter element and ceramic foam disk samples. Real gas validation of the determined model gas activity of the catalytic Filter of combined design in a bench-scale gasifier was performed to check-up, if model gas conversions can be used as bases for the prediction of real tar conversions. A calculation of the model gas activity of the catalytic Filter at a superficial velocity of 2 cm/s based on the disk measurements results to 99% naphthalene conversion at 850 °C in the absence of H 2 S and 94% in the presence of 100 ppmv H 2 S. At 800 °C, the calculated conversion is 95% in the absence and 70% in the presence of 100 ppmv H 2 S resulting in an estimated conversion of 85% at an H 2 S content of 40 ppmv. This value is comparable with the measured real tar conversion of 81% at 790 °C and a superficial velocity of 2.5 cm/s.

  • First Al2O3 based catalytic Filter Candles operating in the fluidized bed gasifier freeboard
    Fuel, 2012
    Co-Authors: Sergio Rapagna, Katia Gallucci, Manuela Di Marcello, Manfred Nacken, Steffen Heidenreich, Pier Ugo Foscolo, Muriel Matt
    Abstract:

    Abstract Al 2 O 3 based grain-sintered Filter element support was first impregnated with a fine, wet-milled suspension of a MgO–Al 2 O 3 and successively with nickel nitrate hexahydrate. The catalytic Filter Candle was inserted in the freeboard of a 0.1 m I.D. fluidized bed biomass gasifier, in order to obtain a very compact gasification and hot gas cleaning unit. Continuous catalytic steam gasification runs of almond shells have been performed in a temperature range of 808–813 °C (maintained by means of an electric furnace), and the volume composition of the product gas has been analyzed by means of IR, UV and TCD facilities for online detection of CO, CO 2 , CH 4 , H 2 , NH 3 and H 2 S. A 20 h test has been performed with intermediate char burning steps. The measured gas yield was 2.09 Nm 3 /kg daf , meanwhile the gas composition in % by volume was H 2  = 56, CO = 22, CO 2  = 20, and CH 4  = 2. NH 3 and H 2 S in the dry gas were 60–80 ppmv and 10–15 ppmv, respectively.

  • gas cleaning gas conditioning and tar abatement by means of a catalytic Filter Candle in a biomass fluidized bed gasifier
    Bioresource Technology, 2010
    Co-Authors: Sergio Rapagna, Katia Gallucci, Manuela Di Marcello, Muriel Matt, Manfred Nacken, Steffen Heidenreich, Pier Ugo Foscolo
    Abstract:

    Abstract A bench-scale fluidized-bed biomass gasification plant, operating at atmospheric pressure and temperature within the range 800–820 °C, has been used to test an innovative gas cleaning device: a catalytic Filter Candle fitted into the bed freeboard. This housing of the gas conditioning system within the gasifier itself results in a very compact unit and greatly reduced thermal losses. Long term (22 h) tests were performed on the gasifier both with and without the catalytic Candle Filter, under otherwise identical conditions. Analysis of the product gas for the two cases showed the catalytic filtration to give rise to notable improvements in both gas quality and gas yield: an increase in hydrogen yield of 130% and an overall increase in gas yield of 69% – with corresponding decreases in methane and tar content of 20% and 79%, respectively. HPLC/UV analysis was used to characterize the tar compounds.

Pier Ugo Foscolo - One of the best experts on this subject based on the ideXlab platform.

  • New DeTar catalytic Filter with integrated catalytic ceramic foam: Catalytic activity under model and real bio syngas conditions
    Fuel Processing Technology, 2015
    Co-Authors: Manfred Nacken, Sergio Rapagna, Katia Gallucci, Steffen Heidenreich, Gino V. Baron, A. D'orazio, Joeri F. M. Denayer, Pier Ugo Foscolo
    Abstract:

    Abstract The catalytic activity of a new catalytic Filter of combined design consisting of a catalytic Filter Candle with an integrated catalytic ceramic foam was calculated under model gas conditions at 800 and 850 °C in the absence and presence of 100 ppmv H 2 S on the basis of separate and combined measurements of appropriate catalytic Filter element and ceramic foam disk samples. Real gas validation of the determined model gas activity of the catalytic Filter of combined design in a bench-scale gasifier was performed to check-up, if model gas conversions can be used as bases for the prediction of real tar conversions. A calculation of the model gas activity of the catalytic Filter at a superficial velocity of 2 cm/s based on the disk measurements results to 99% naphthalene conversion at 850 °C in the absence of H 2 S and 94% in the presence of 100 ppmv H 2 S. At 800 °C, the calculated conversion is 95% in the absence and 70% in the presence of 100 ppmv H 2 S resulting in an estimated conversion of 85% at an H 2 S content of 40 ppmv. This value is comparable with the measured real tar conversion of 81% at 790 °C and a superficial velocity of 2.5 cm/s.

  • First Al2O3 based catalytic Filter Candles operating in the fluidized bed gasifier freeboard
    Fuel, 2012
    Co-Authors: Sergio Rapagna, Katia Gallucci, Manuela Di Marcello, Manfred Nacken, Steffen Heidenreich, Pier Ugo Foscolo, Muriel Matt
    Abstract:

    Abstract Al 2 O 3 based grain-sintered Filter element support was first impregnated with a fine, wet-milled suspension of a MgO–Al 2 O 3 and successively with nickel nitrate hexahydrate. The catalytic Filter Candle was inserted in the freeboard of a 0.1 m I.D. fluidized bed biomass gasifier, in order to obtain a very compact gasification and hot gas cleaning unit. Continuous catalytic steam gasification runs of almond shells have been performed in a temperature range of 808–813 °C (maintained by means of an electric furnace), and the volume composition of the product gas has been analyzed by means of IR, UV and TCD facilities for online detection of CO, CO 2 , CH 4 , H 2 , NH 3 and H 2 S. A 20 h test has been performed with intermediate char burning steps. The measured gas yield was 2.09 Nm 3 /kg daf , meanwhile the gas composition in % by volume was H 2  = 56, CO = 22, CO 2  = 20, and CH 4  = 2. NH 3 and H 2 S in the dry gas were 60–80 ppmv and 10–15 ppmv, respectively.

  • Hot syngas filtration in the freeboard of a fluidized bed gasifier: Development of a CFD model
    Powder Technology, 2012
    Co-Authors: Andrea Di Carlo, Pier Ugo Foscolo
    Abstract:

    Abstract An Eulerian–Lagrangian CFD model was described and validated against experimental findings, able to simulate the fluid dynamic behavior of gas and solid particles inside a fluidized bed freeboard where filtration Candles are inserted, with the aim to integrate the steam gasification of biomass and the hot gas cleaning system into one reactor vessel. Fluidization tests with a cold model consisting of a bed of sand particles containing also a fraction of Geldart group A/C fine powder were carried out batchwise in a 10-cm ID column, at different operating conditions, to quantify solid ejection into the freeboard zone. A Particle Elutriation Model (PEM) was proposed to set the boundary condition at the bed surface (freeboard inlet) for fine particles. This model accounted for elutriation and attrition based on the assumption that the generation of fines by attrition is a nonlinear function of time and depends on the percentage of agglomerated fines. By fitting the experimental data with PEM equations, the elutriation rate constants and attrition rates were evaluated at various particle diameters, and it could be observed that the entrainment rate at low air velocities was affected by interparticle adhesion forces. The PEM was then interfaced with the CFD open source software MFIX in order to simulate transport of particles in the freeboard, the deposition of fine particles on the Filter Candle and thus the pressure drop profile as a function of time due to cake formation on the Candle surface. A k-e model was used for turbulence. A Discrete Random Walk (DRW) model was implemented to consider the particles turbulent dispersion. 2D simulations of the freeboard were carried out at different static bed height (10 and 20 cm), superficial gas velocity (11 and 16 cm/s) and mass of fines initially charged inside the bed. The numerical predictions were compared with experimental results obtained when a filtration Candle is inserted in the freeboard of a bubbling fluidized bed system with similar dimensions and operated at the same conditions as those simulated by the model. In order to match experimental and numerical results, it was necessary to assume that clusters of very fine particles (with a diameter smaller than 20 μm) were transported in the freeboard. The results of the numerical model were in fair agreement with the experimental results.

  • gas cleaning gas conditioning and tar abatement by means of a catalytic Filter Candle in a biomass fluidized bed gasifier
    Bioresource Technology, 2010
    Co-Authors: Sergio Rapagna, Katia Gallucci, Manuela Di Marcello, Muriel Matt, Manfred Nacken, Steffen Heidenreich, Pier Ugo Foscolo
    Abstract:

    Abstract A bench-scale fluidized-bed biomass gasification plant, operating at atmospheric pressure and temperature within the range 800–820 °C, has been used to test an innovative gas cleaning device: a catalytic Filter Candle fitted into the bed freeboard. This housing of the gas conditioning system within the gasifier itself results in a very compact unit and greatly reduced thermal losses. Long term (22 h) tests were performed on the gasifier both with and without the catalytic Candle Filter, under otherwise identical conditions. Analysis of the product gas for the two cases showed the catalytic filtration to give rise to notable improvements in both gas quality and gas yield: an increase in hydrogen yield of 130% and an overall increase in gas yield of 69% – with corresponding decreases in methane and tar content of 20% and 79%, respectively. HPLC/UV analysis was used to characterize the tar compounds.

  • Gas cleaning, gas conditioning and tar abatement by means of a catalytic Filter Candle in a biomass fluidized-bed gasifier.
    Bioresource technology, 2010
    Co-Authors: Sergio Rapagna, Katia Gallucci, Manuela Di Marcello, Muriel Matt, Manfred Nacken, Steffen Heidenreich, Pier Ugo Foscolo
    Abstract:

    A bench-scale fluidized-bed biomass gasification plant, operating at atmospheric pressure and temperature within the range 800-820 degrees C, has been used to test an innovative gas cleaning device: a catalytic Filter Candle fitted into the bed freeboard. This housing of the gas conditioning system within the gasifier itself results in a very compact unit and greatly reduced thermal losses. Long term (22h) tests were performed on the gasifier both with and without the catalytic Candle Filter, under otherwise identical conditions. Analysis of the product gas for the two cases showed the catalytic filtration to give rise to notable improvements in both gas quality and gas yield: an increase in hydrogen yield of 130% and an overall increase in gas yield of 69% - with corresponding decreases in methane and tar content of 20% and 79%, respectively. HPLC/UV analysis was used to characterize the tar compounds.