The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jihong Moon - One of the best experts on this subject based on the ideXlab platform.
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effects of hydrothermal treatment of sewage sludge on pyrolysis and Steam Gasification
Energy Conversion and Management, 2015Co-Authors: Jihong Moon, Jungho Hwang, Tae Young Mun, Won Yang, Uendo Lee, Ensuk Jang, Changsik ChoiAbstract:Hydrothermal treatment is a promising option for pretreatment drying of organic waste, due to its low energy consumption and contribution to increasing fuel energy density. In this study, the characteristics of hydrothermally treated sewage sludge were investigated, and pyrolysis and Steam Gasification were performed with the sludge before and after hydrothermal treatment. The overall composition of product gases from treated sludge was similar to that obtained from Steam Gasification of wood chips, particularly under high-temperature conditions. In addition, the increase in lignin content of sewage sludge following hydrothermal treatment could help enhance methane yield in product gas during pyrolysis and Steam Gasification. The findings suggest that hydrothermal treatment is an appropriate method for improving sewage sludge for use as an alternative to biomass and fossil fuels.
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transient behavior of devolatilization and char reaction during Steam Gasification of biomass
Bioresource Technology, 2013Co-Authors: Jihong Moon, Jungho HwangAbstract:Steam Gasification of biomass is a promising method for producing high quality syngas for polygeneration. During the Steam Gasification, devolatilization and char reaction are key steps of syngas production and the contributions of the two reactions are highly related to Gasification conditions. In this study, the transient characteristics of devolatilization and char reaction in biomass Steam Gasification were investigated by monitoring cumulative gas production and composition changes in terms of reaction temperature and S/B ratio. Contribution of each reaction stage on the product gas yield was studied in detail. The results provide important insight for understanding the complex nature of biomass Gasification and will guide future improvements to the biomass Gasification process.
Ashwani K. Gupta - One of the best experts on this subject based on the ideXlab platform.
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hydrogen and syngas yield from residual branches of oil palm tree using Steam Gasification
International Journal of Hydrogen Energy, 2011Co-Authors: Nimit Nipattummakul, Islam Ahmed, Ashwani K. Gupta, Somrat KerdsuwanAbstract:Abstract Wastes produced during oil palm production from agro-industries have great potential as a source of renewable energy in agriculturally rich countries, such as Thailand and Malaysia. Clean chemical energy recovery from oil palm residual branches via Steam Gasification is investigated here. A semi-batch reactor was used to investigate the Gasification of palm trunk wastes at different reactor temperatures in the range of 600 to 1000 °C. The Steam flow rate was fixed at 3.10 g/min. Characteristics and overall yield of syngas properties are presented and discussed. Results show that Gasification temperature slightly affects the overall syngas yield. However, the chemical composition of the syngas varied tremendously with the reactor temperature. Consequently, the syngas heating value and ratio of energy yield to energy consumed were found to be strongly dependent on the reactor temperature. Both the heating value and energy yield ratio increased with increase in reactor temperature. Gasification duration and the Steam to solid fuel ratio indicate that reaction rate becomes progressively slower at reactor temperatures of less than 700 °C. The results reveal that Steam Gasification of oil palm residues should not be carried out at reactor temperatures lower than 700 °C, since a large amount of Steam is consumed per unit mass of the sample in order to gasify the residual char.
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high temperature Steam Gasification of wastewater sludge
Applied Energy, 2010Co-Authors: Islam Ahmed, Nimit Nipattummakul, Somrat Kerdsuwan, Ashwani K. GuptaAbstract:High temperature Steam Gasification is one of the most promising, viable, effective and efficient technology for clean conversion of wastes to energy with minimal or negligible environmental impact. Gasification can add value by transforming the waste to low or medium heating value fuel which can be used as a source of clean energy or co-fired with other fuels in current power systems. Wastewater sludge is a good source of sustainable fuel after fuel reforming with Steam Gasification. The use of Steam is shown to provide value added characteristics to the sewage sludge with increased hydrogen content as well total energy. Results obtained on the syngas properties from sewage sludge are presented here at various Steam to carbon ratios at a reactor temperature of 1173 K. Effect of Steam to carbon ratio on syngas properties are evaluated with specific focus on the amounts of syngas yield, syngas composition, hydrogen yield, energy yield, and apparent thermal efficiency. The apparent thermal efficiency is similar to cold gas efficiency used in industry and was determined from the ratio of energy in syngas to energy in the solid sewage sludge feedstock. A laboratory scale semi-batch type gasifier was used to determine the evolutionary behavior of the syngas properties using calibrated experiments and diagnostic facilities. Results showed an optimum Steam to carbon ratio of 5.62 for the range of conditions examined here for syngas yield, hydrogen yield, energy yield and energy ratio of syngas to sewage sludge fuel. The results show that Steam Gasification provided 25% increase in energy yield as compared to pyrolysis at the same temperature.
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syngas yield during pyrolysis and Steam Gasification of paper
Applied Energy, 2009Co-Authors: Islam Ahmed, Ashwani K. GuptaAbstract:Abstract Main characteristics of gaseous yield from Steam Gasification have been investigated experimentally. Results of Steam Gasification have been compared to that of pyrolysis. The temperature range investigated were 600–1000 °C in steps of 100 °C. Results have been obtained under pyrolysis conditions at same temperatures. For Steam Gasification runs, Steam flow rate was kept constant at 8.0 g/min. Investigated characteristics were evolution of syngas flow rate with time, hydrogen flow rate and chemical composition of syngas, energy yield and apparent thermal efficiency. Residuals from both processes were quantified and compared as well. Material destruction, hydrogen yield and energy yield is better with Gasification as compared to pyrolysis. This advantage of the Gasification process is attributed mainly to char Gasification process. Char Gasification is found to be more sensitive to the reactor temperature than pyrolysis. Pyrolysis can start at low temperatures of 400 °C; however char Gasification starts at 700 °C. A partial overlap between Gasification and pyrolysis exists and is presented here. This partial overlap increases with increase in temperature. As an example, at reactor temperature 800 °C this overlap represents around 27% of the char Gasification process and almost 95% at reactor temperature 1000 °C.
Hermann Hofbauer - One of the best experts on this subject based on the ideXlab platform.
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fuel flexible Gasification with an advanced 100 kw dual fluidized bed Steam Gasification pilot plant
Energy, 2018Co-Authors: F Benedikt, J C Schmid, J Fuchs, Anna Magdalena Mauerhofer, Stefan Muller, Hermann HofbauerAbstract:Abstract Steam Gasification enables the conversion of heterogeneous solid fuels into homogeneous gaseous energy carriers. The utilization of biogenic residues and waste fractions as fuel for this technology offers a sustainable waste management solution to produce heat and power, secondary fuels and valuable chemicals after several cleaning and upgrading steps of the product gas. However, residues and waste fuels show unfavorable properties for Gasification and, therefore, cause technical challenges. This paper presents experimental results carried out at an advanced 100 kWth dual fluidized bed Steam Gasification pilot plant from nine single test runs. In the following the fuels that were gasified will be listed: (i) Five biogenic fuels, mainly residues: softwood, sugar cane bagasse, exhausted olive pomace, bark and rice husks; (ii) two different waste-derived fuels: a municipal solid waste fraction and a shredder light fraction; and (iii) a mixture of municipal solid waste fraction with a 25% blending of lignite based on lower heating value as well as pure lignite. Thereby, various product gas qualities were generated. The presented results offer the basis for a sustainable and promising waste management solution for the tested waste fuels.
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Techno-economic assessment of hydrogen production based on dual fluidized bed biomass Steam Gasification, biogas Steam reforming, and alkaline water electrolysis processes
Energy Conversion and Management, 2017Co-Authors: Jingang Yao, Florian Benedikt, Michael Kraussler, Hermann HofbauerAbstract:In this paper, three CO2-neutral H2 production processes were investigated. The three employed technologies were dual fluidized bed (DFB) biomass Steam Gasification, biogas Steam reforming (BSR), and alkaline electrolysis (AEL) powered by renewable electricity with their necessary downstream separation and purification process steps. Aspen Plus process simulations were carried out in order to calculate the mass and energy balances of the three processes. In addition, a techno-economic assessment was carried out for a fictitious business producing H2 at a rate of 90 kg h−1 in Austria in 2016. This assumption was used so that the economic feasibility of these investigated processes could be directly compared. The simulation results show that the DFB biomass Steam Gasification process has a higher H2 conversion rate (51.4%) but a lower fuel based H2 production efficiency (38.9%) than the BSR process (27.2% and 47.0%, respectively). Moreover, the alkaline electrolysis process shows the highest energy based H2 conversion efficiency at about 66%. The results of the economic assessment show that the DFB biomass Steam Gasification process has investment costs of 12.1 MEUR followed by the biogas Steam reforming process with investment costs of 9.9 MEUR. The alkaline electrolysis process has investment costs of 4.4 MEUR. However, the after tax H2 break-even price of the DFB process is the lowest with 0.148 EUR kWh−1. The BSR process has an after tax H2 break-even price of 0.152 EUR kWh−1 and the AEL process has an after tax H2 break-even price of 0.191 EUR kWh−1. The net present value (NPV) calculations reveal that the BSR process has the highest NPV, followed by the AEL process and the DFB biomass Steam Gasification process. However, the NPV of all three processes are very similar. In general, all three H2 production processes perform at the same level based on the results of the process simulation and the chosen economic assumptions.
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hydrogen production within a polygeneration concept based on dual fluidized bed biomass Steam Gasification
Biomass & Bioenergy, 2016Co-Authors: Michael Kraussler, Matthias Binder, Philipp Schindler, Hermann HofbauerAbstract:Dual fluidized bed biomass Steam Gasification generates a high calorific, practically nitrogen-free product gas with a volumetric H2 content of about 40%. Therefore, this could be a promising route for a polygeneration concept aiming at the production of valuable gases (for example H2), electricity, and heat. In this paper, a lab-scale process chain, based on state of the art unit operations, which processed a tar-rich product gas from a commercial dual fluidized bed biomass Steam Gasification plant, is investigated regarding H2 production within a polygeneration concept. The lab-scale process chain employed a water gas shift step, two gas scrubbing steps, and a pressure swing adsorption step. During the investigations, a volumetric H2 concentration of 99.9% with a specific H2 production of 30 g kg−1 biomass was reached. In addition, a valuable off-gas stream with a lower heating value of 7.9 MJ m−3 was produced. Moreover, a techno-economic assessment shows the economic feasibility of such a polygeneration concept, if certain feed in tariffs for renewable electricity and H2 exist. Consequently, these results show, that the dual fluidized bed biomass Steam Gasification technology is a promising route for a polygeneration concept, which aims at the production of H2, electricity, and district heat.
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deposit build up and ash behavior in dual fluid bed Steam Gasification of logging residues in an industrial power plant
Fuel Processing Technology, 2015Co-Authors: Matthias Kuba, Friedrich Kirnbauer, Dan Bostrom, Marcus Ohman, Hermann HofbauerAbstract:A promising way to substitute fossil fuels for production of electricity, heat, fuels for transportation and synthetic chemicals is biomass Steam Gasification in a dual fluidized bed (DFB). Using l ...
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the mechanism of bed material coating in dual fluidized bed biomass Steam Gasification plants and its impact on plant optimization
Powder Technology, 2013Co-Authors: Friedrich Kirnbauer, Hermann HofbauerAbstract:Abstract The bed material and especially its catalytic activity plays an important role in biomass Steam Gasification in dual fluidized bed gasifiers. The bed material is modified by interaction with biomass ash during operation of the Gasification plant forming layers at the particles which are induced by the biomass ash. Optimization of dual fluidized biomass Steam Gasification will have significant influence on the process variables such as temperatures, inorganic composition and product gas composition. The influence of these changes on layer formation is still unknown. This paper summarizes results of investigations about bed material characteristics taken from the industrial-scale biomass Steam Gasification plant in Gussing where woody biomass is used as fuel. Analyses of the surface and the crystal structures of the bed material particles treated in Gasification and combustion atmospheres were carried out. The thermal behavior of used olivine and fresh olivine in different atmospheres was analyzed. A suggestion for the mechanism of formation of the layers is presented and the influence of possible optimization measures is discussed. A change in the elemental composition of the surface was not detectable but a slight change in the crystal structure. Thermal investigations show a weak endothermic weight loss with used olivine in a CO 2 -rich atmosphere which could not be determined with fresh olivine. The formation of layers at the olivine particles is considered to be caused by the intensive contact with burning char particles in the combustion reactor.
Nimit Nipattummakul - One of the best experts on this subject based on the ideXlab platform.
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hydrogen and syngas yield from residual branches of oil palm tree using Steam Gasification
International Journal of Hydrogen Energy, 2011Co-Authors: Nimit Nipattummakul, Islam Ahmed, Ashwani K. Gupta, Somrat KerdsuwanAbstract:Abstract Wastes produced during oil palm production from agro-industries have great potential as a source of renewable energy in agriculturally rich countries, such as Thailand and Malaysia. Clean chemical energy recovery from oil palm residual branches via Steam Gasification is investigated here. A semi-batch reactor was used to investigate the Gasification of palm trunk wastes at different reactor temperatures in the range of 600 to 1000 °C. The Steam flow rate was fixed at 3.10 g/min. Characteristics and overall yield of syngas properties are presented and discussed. Results show that Gasification temperature slightly affects the overall syngas yield. However, the chemical composition of the syngas varied tremendously with the reactor temperature. Consequently, the syngas heating value and ratio of energy yield to energy consumed were found to be strongly dependent on the reactor temperature. Both the heating value and energy yield ratio increased with increase in reactor temperature. Gasification duration and the Steam to solid fuel ratio indicate that reaction rate becomes progressively slower at reactor temperatures of less than 700 °C. The results reveal that Steam Gasification of oil palm residues should not be carried out at reactor temperatures lower than 700 °C, since a large amount of Steam is consumed per unit mass of the sample in order to gasify the residual char.
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high temperature Steam Gasification of wastewater sludge
Applied Energy, 2010Co-Authors: Islam Ahmed, Nimit Nipattummakul, Somrat Kerdsuwan, Ashwani K. GuptaAbstract:High temperature Steam Gasification is one of the most promising, viable, effective and efficient technology for clean conversion of wastes to energy with minimal or negligible environmental impact. Gasification can add value by transforming the waste to low or medium heating value fuel which can be used as a source of clean energy or co-fired with other fuels in current power systems. Wastewater sludge is a good source of sustainable fuel after fuel reforming with Steam Gasification. The use of Steam is shown to provide value added characteristics to the sewage sludge with increased hydrogen content as well total energy. Results obtained on the syngas properties from sewage sludge are presented here at various Steam to carbon ratios at a reactor temperature of 1173 K. Effect of Steam to carbon ratio on syngas properties are evaluated with specific focus on the amounts of syngas yield, syngas composition, hydrogen yield, energy yield, and apparent thermal efficiency. The apparent thermal efficiency is similar to cold gas efficiency used in industry and was determined from the ratio of energy in syngas to energy in the solid sewage sludge feedstock. A laboratory scale semi-batch type gasifier was used to determine the evolutionary behavior of the syngas properties using calibrated experiments and diagnostic facilities. Results showed an optimum Steam to carbon ratio of 5.62 for the range of conditions examined here for syngas yield, hydrogen yield, energy yield and energy ratio of syngas to sewage sludge fuel. The results show that Steam Gasification provided 25% increase in energy yield as compared to pyrolysis at the same temperature.
Islam Ahmed - One of the best experts on this subject based on the ideXlab platform.
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hydrogen and syngas yield from residual branches of oil palm tree using Steam Gasification
International Journal of Hydrogen Energy, 2011Co-Authors: Nimit Nipattummakul, Islam Ahmed, Ashwani K. Gupta, Somrat KerdsuwanAbstract:Abstract Wastes produced during oil palm production from agro-industries have great potential as a source of renewable energy in agriculturally rich countries, such as Thailand and Malaysia. Clean chemical energy recovery from oil palm residual branches via Steam Gasification is investigated here. A semi-batch reactor was used to investigate the Gasification of palm trunk wastes at different reactor temperatures in the range of 600 to 1000 °C. The Steam flow rate was fixed at 3.10 g/min. Characteristics and overall yield of syngas properties are presented and discussed. Results show that Gasification temperature slightly affects the overall syngas yield. However, the chemical composition of the syngas varied tremendously with the reactor temperature. Consequently, the syngas heating value and ratio of energy yield to energy consumed were found to be strongly dependent on the reactor temperature. Both the heating value and energy yield ratio increased with increase in reactor temperature. Gasification duration and the Steam to solid fuel ratio indicate that reaction rate becomes progressively slower at reactor temperatures of less than 700 °C. The results reveal that Steam Gasification of oil palm residues should not be carried out at reactor temperatures lower than 700 °C, since a large amount of Steam is consumed per unit mass of the sample in order to gasify the residual char.
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high temperature Steam Gasification of wastewater sludge
Applied Energy, 2010Co-Authors: Islam Ahmed, Nimit Nipattummakul, Somrat Kerdsuwan, Ashwani K. GuptaAbstract:High temperature Steam Gasification is one of the most promising, viable, effective and efficient technology for clean conversion of wastes to energy with minimal or negligible environmental impact. Gasification can add value by transforming the waste to low or medium heating value fuel which can be used as a source of clean energy or co-fired with other fuels in current power systems. Wastewater sludge is a good source of sustainable fuel after fuel reforming with Steam Gasification. The use of Steam is shown to provide value added characteristics to the sewage sludge with increased hydrogen content as well total energy. Results obtained on the syngas properties from sewage sludge are presented here at various Steam to carbon ratios at a reactor temperature of 1173 K. Effect of Steam to carbon ratio on syngas properties are evaluated with specific focus on the amounts of syngas yield, syngas composition, hydrogen yield, energy yield, and apparent thermal efficiency. The apparent thermal efficiency is similar to cold gas efficiency used in industry and was determined from the ratio of energy in syngas to energy in the solid sewage sludge feedstock. A laboratory scale semi-batch type gasifier was used to determine the evolutionary behavior of the syngas properties using calibrated experiments and diagnostic facilities. Results showed an optimum Steam to carbon ratio of 5.62 for the range of conditions examined here for syngas yield, hydrogen yield, energy yield and energy ratio of syngas to sewage sludge fuel. The results show that Steam Gasification provided 25% increase in energy yield as compared to pyrolysis at the same temperature.
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syngas yield during pyrolysis and Steam Gasification of paper
Applied Energy, 2009Co-Authors: Islam Ahmed, Ashwani K. GuptaAbstract:Abstract Main characteristics of gaseous yield from Steam Gasification have been investigated experimentally. Results of Steam Gasification have been compared to that of pyrolysis. The temperature range investigated were 600–1000 °C in steps of 100 °C. Results have been obtained under pyrolysis conditions at same temperatures. For Steam Gasification runs, Steam flow rate was kept constant at 8.0 g/min. Investigated characteristics were evolution of syngas flow rate with time, hydrogen flow rate and chemical composition of syngas, energy yield and apparent thermal efficiency. Residuals from both processes were quantified and compared as well. Material destruction, hydrogen yield and energy yield is better with Gasification as compared to pyrolysis. This advantage of the Gasification process is attributed mainly to char Gasification process. Char Gasification is found to be more sensitive to the reactor temperature than pyrolysis. Pyrolysis can start at low temperatures of 400 °C; however char Gasification starts at 700 °C. A partial overlap between Gasification and pyrolysis exists and is presented here. This partial overlap increases with increase in temperature. As an example, at reactor temperature 800 °C this overlap represents around 27% of the char Gasification process and almost 95% at reactor temperature 1000 °C.
