The Experts below are selected from a list of 22503 Experts worldwide ranked by ideXlab platform
Kentaro Umeki - One of the best experts on this subject based on the ideXlab platform.
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high temperature steam only gasification of Woody Biomass
2010Co-Authors: Kentaro Umeki, Kouichi Yamamoto, Tomoaki Namioka, Kunio YoshikawaAbstract:We have studied a high temperature steam gasification process to generate hydrogen-rich fuel gas from Woody Biomass. In this study, the performance of the gasification system which employs only hig ...
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high temperature steam only gasification of Woody Biomass
2010Co-Authors: Kentaro Umeki, Kouichi Yamamoto, Tomoaki Namioka, Kunio YoshikawaAbstract:We have studied a high temperature steam gasification process to generate hydrogen-rich fuel gas from Woody Biomass. In this study, the performance of the gasification system which employs only high temperature steam exceeding 1200Â K as the gasifying agent was evaluated in a 1.2 ton/day-scale demonstration plant. A numerical analysis was also carried out to analyze the experimental results. Both the steam temperature and the molar ratio of steam to carbon (S/C ratio) affected the reaction temperature which strongly affects the gasified gas composition. The H2 fraction in the produced gas was 35-55 vol.% at the outlet of the gasifier. Under the experimental conditions, S/C ratio had a significant effect on the gas composition through the dominant reaction, water-gas shift reaction. The tar concentration in the produced gas from the high temperature steam gasification process was higher than that from the oxygen-blown gasification processes. The highest cold gas efficiency was 60.4%. However, the gross cold gas efficiency was 35%, which considers the heat supplied by high temperature steam. The ideal cold gas efficiency of the whole system with heat recovery processes was 71%.
Yoshizo Suzuki - One of the best experts on this subject based on the ideXlab platform.
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steam gasification of Woody Biomass in a circulating dual bubbling fluidized bed system
2008Co-Authors: Koichi Matsuoka, Koji Kuramoto, Takahiro Murakami, Yoshizo SuzukiAbstract:Partial oxidation is generally applied for Woody Biomass gasification. However, the calorific value of gaseous products is relatively low. To increase the calorific value of the gaseous product, a circulating dual bubbling fluidized bed (CDBFB) system for Woody Biomass gasification based on a concept of separation of combustion zone from gasification zone was developed in this study. The CDBFB consisted of two bubbling fluidized beds, with one serving as a gasifier and the other as a combustor. Two kinds of sawdusts were gasified with steam in the CDBFB at 773, 873, 973, and 1073 K. Almost all the tar evolved from the sawdust samples was captured by the porous γ-alumina particle bed material in the gasifier. The tar deposited on the alumina, referred to herein as coke, and the resulting char were gasified with steam in the gasifier. Since the residence time of solid in the gasifier can be controlled, coke as well as char was effectively gasified with steam in comparison with the conventional circulating f...
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mechanism of Woody Biomass pyrolysis and gasification in a fluidized bed of porous alumina particles
2006Co-Authors: Koichi Matsuoka, Koji Kuramoto, Hiroyuki Hatano, Takaaki Shinbori, Tetsuya Nanba, Atsuko Morita, Yoshizo SuzukiAbstract:To understand the mechanism of steam gasification of Woody Biomass, pyrolysis and gasification were carried out at 773 and 973 K on porous γ-alumina in a two-stage fluidized bed reactor. Significant amounts of volatiles, including gas and tarry materials, were formed upon devolatilization, but the tar was mostly captured by the alumina. The tar captured on the alumina was subsequently reformed with the steam to H2 and CO. However, little of the char was gasified under the present conditions. CO and water molecules penetrated into the large pores of the char, allowing the water−gas shift reaction to occur on the active sites on the surface of the char. Although the char itself was not gasified at these relatively low temperatures, it played an important role in the water−gas shift reaction.
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hydrogen production from Woody Biomass by steam gasification using a co2 sorbent
2005Co-Authors: Toshiaki Hanaoka, Yoshizo Suzuki, Takahiro Yoshida, Shinji Fujimoto, Kenji Kamei, Michiaki Harada, Hiroyuki Hatano, Shinya Yokoyama, Tomoaki MinowaAbstract:Abstract In H 2 production from Woody Biomass by steam gasification using CaO as a CO 2 sorbent, the effect of reaction parameters such as the molar ratio of CaO to carbon in the Woody Biomass ( [ Ca ] / [ C ] ) , reaction pressure, and reaction temperature was investigated on H 2 yield and conversion to gas. In the absence of CaO, the product gas contained CO 2 . On the other hand, in the presence of CaO ( [ Ca ] / [ C ] = 1 , 2 , and 4), no CO 2 was detected in the product gas. At a [ Ca ] / [ C ] of 2, the maximum yield of H 2 was obtained. The H 2 yield and conversion to gas were largely dependent on the reaction pressure, and exhibited the maximum value at 0.6 MPa . It is noteworthy that H 2 was obtained from Woody Biomass at a much lower pressure compared to other carbonaceous materials such as coal ( > 12 MPa ) and heavy oil ( > 4.2 MPa ) in steam gasification using a CO 2 sorbent. H 2 yield increased with increasing reaction temperature. Woody Biomass is the one of the most appropriate carbonaceous materials in H 2 production by steam gasification using CaO as a CO 2 sorbent, taking the reaction pressure into account.
Emanuele Massetti - One of the best experts on this subject based on the ideXlab platform.
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trade of Woody Biomass for electricity generation under climate mitigation policy
2014Co-Authors: Alice Favero, Emanuele MassettiAbstract:Abstract Bio-energy with carbon capture and sequestration (BECCS) has the potential to be a key mitigation option, because it can generate electricity and absorb emissions at the same time. However, Biomass is not distributed evenly across the globe and regions with a potentially high demand might be constrained by limited domestic supply. Therefore, climate mitigation policies might create the incentive to trade Biomass internationally. This paper uses scenarios generated by the integrated assessment model WITCH to study trade of Woody Biomass from multiple perspectives: the volume of Biomass traded, its value, the impact on other power generation technologies and on the efficiency of mitigation policy. The policy scenarios consist of three representative carbon tax policies (4.8 W/m 2 , 3.8 W/m 2 and 3.2 W/m 2 radiative forcing values in 2100) and a cap-and-trade scheme (3.8 W/m 2 in 2100). Results show that the incentive to trade Biomass is high: at least 50% of Biomass consumed globally is traded internationally. Regions trade 13–69 EJ/yr of Woody Biomass in 2050 and 55–81 EJ/yr in 2100. In 2100 the value of Biomass traded is equal to US$ 0.7–7.2 Trillion. Trade of Woody Biomass substantially increases the efficiency of the mitigation policy. In the tax scenarios, abatement increases by 120–323 Gt CO 2 over the century. In the cap-and-trade scenario Biomass trade reduces the price of emission allowances by 34% in 2100 and cumulative discounted policy costs by 14%.
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trade of Woody Biomass for electricity generation under climate mitigation policy
2013Co-Authors: Alice Favero, Emanuele MassettiAbstract:Bio-energy has the potential to be a key mitigation option if combined with carbon capture and sequestration (BECCS) because it generates electricity and absorbs emissions at the same time. However, Biomass is not distributed evenly across the globe, and regions with a potentially high demand might be constrained by limited domestic supply. Therefore, climate mitigation policies might create the incentive to trade Biomass internationally. This paper uses scenarios generated by the integrated assessment model WITCH to study trade of Woody Biomass from multiple perspectives: the volume of Biomass traded, its value, the impact on other power generation technologies and on marginal abatement costs. The policy scenarios consist of three representative carbon tax policies (4.8 W/m2, 3.8 W/m2 and 3.2 W/m2 radiative forcing in 2100) and a cap-and-trade scheme (3.8 W/m2 in 2100). Results show that the incentive to trade Biomass is high: at least 50% of Biomass consumed globally is from the international market. Regions trade 13-69 EJ/yr of Woody Biomass in 2050 and 55-81 EJ/yr in 2100. In 2100 the value of Biomass traded is equal to US$ 0.7-7.2 Trillion. Trade of Woody Biomass sensibly reduces marginal abatement costs. In the tax scenarios, abatement increases by 120-323 Gt CO2 over the century. In the cap-and-trade scenario Biomass trade reduces the price of emission allowances by 34% in 2100 and cumulative discounted policy costs by 14%.
Sayeed R. Mehmood - One of the best experts on this subject based on the ideXlab platform.
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determinants of nonindustrial private forest landowner willingness to accept price offers for Woody Biomass
2012Co-Authors: G C Shivan, Sayeed R. MehmoodAbstract:Abstract Nonindustrial private forests (NIPF) of the southern U.S., containing large quantities of small diameter trees are often viewed as the potential sources of Woody Biomass for future bioenergy production. Use of logging residues and non-marketable small diameter trees available in these forests, are thought to create economic opportunities for NIPF owners and contribute in maintaining healthy forest systems. However, in the absence of a well-defined market, it is difficult to predict the willingness of landowners for supplying Biomass from their forests. This study uses multinomial logit models to understand landowners' willingness/unwillingness to supply Biomass at hypothetical price levels and examines landowner, forest, and demographic characteristics underlying these decisions. The results indicate significant association between landowners' bid acceptance decisions and factors such as, forest tract size, size of trees in the forest, distance of landowners' residence from the forest, landowners' age, previous harvesting experience, price of timber, and forest management objectives.
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factors affecting nonindustrial private forest landowners willingness to supply Woody Biomass for bioenergy
2011Co-Authors: Omkar Joshi, Sayeed R. MehmoodAbstract:Abstract Bioenergy is a renewable form of potential alternative to traditional fossil fuels that has come to the forefront as a result of recent concerns over high price of fuels, national security, and climate change. Nonindustrial private forest (NIPF) landowners form the dominant forest ownership group in the southern United States. These forests often tend to have large quantities of small diameter trees. Use of logging residues and non-marketable small diameter trees for bioenergy production can create economic opportunities for NIPF landowners. The results demonstrated that landowners’ willingness to harvest Woody Biomass was influenced by their ownership objectives, size of the forest, structure and composition of tree species, and demographic characteristics. The model found that relatively younger landowners who owned large acres of forestland with pine plantations or mix forests had the potential to become a preferable choice for contractors, extension foresters and bioenergy industries as they were more likely to supply Woody Biomass for bioenergy. Findings of this study will be useful to bioenergy industries, extension foresters, nonindustrial private forest landowners and policy makers.
Kunio Yoshikawa - One of the best experts on this subject based on the ideXlab platform.
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high temperature steam only gasification of Woody Biomass
2010Co-Authors: Kentaro Umeki, Kouichi Yamamoto, Tomoaki Namioka, Kunio YoshikawaAbstract:We have studied a high temperature steam gasification process to generate hydrogen-rich fuel gas from Woody Biomass. In this study, the performance of the gasification system which employs only hig ...
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high temperature steam only gasification of Woody Biomass
2010Co-Authors: Kentaro Umeki, Kouichi Yamamoto, Tomoaki Namioka, Kunio YoshikawaAbstract:We have studied a high temperature steam gasification process to generate hydrogen-rich fuel gas from Woody Biomass. In this study, the performance of the gasification system which employs only high temperature steam exceeding 1200Â K as the gasifying agent was evaluated in a 1.2 ton/day-scale demonstration plant. A numerical analysis was also carried out to analyze the experimental results. Both the steam temperature and the molar ratio of steam to carbon (S/C ratio) affected the reaction temperature which strongly affects the gasified gas composition. The H2 fraction in the produced gas was 35-55 vol.% at the outlet of the gasifier. Under the experimental conditions, S/C ratio had a significant effect on the gas composition through the dominant reaction, water-gas shift reaction. The tar concentration in the produced gas from the high temperature steam gasification process was higher than that from the oxygen-blown gasification processes. The highest cold gas efficiency was 60.4%. However, the gross cold gas efficiency was 35%, which considers the heat supplied by high temperature steam. The ideal cold gas efficiency of the whole system with heat recovery processes was 71%.
