Gasification efficiency is an important factor that determines the actual technical operation as well as the economic viability of using a gasifier system for energy production. In this study, the impact of the physic...Gasification efficiency is an important factor that determines the actual technical operation as well as the economic viability of using a gasifier system for energy production. In this study, the impact of the physical properties of torrefied bagasse and the influence of gasifier design and operating variables were investigated in a computer simulated downdraft gasification system. Results obtained from the study indicated an interrelationship between feedstock characteristics, especially with regard to feed size, design variables such as throat angle and throat diameter as well as gasifier operating conditions such as temperature of input air and feed input. These variables influenced the efficiency of the gasification process of sugarcane bagasse because of increased enhancement of combustion zone reactions, which liberated huge amount of heat that led to a rise in the temperature of the gasification process. This condition also created increased tar cracking within the gasification system, contributing to reduction in the overall yield of tar.展开更多
Melina wood torrefied at 260℃ for 60 min was agglomerated with lean grade coal fines into composite briquettes using pitch as binder.Torrefied biomass(3%-20%)and coal fines(80%-97%)were blended together to produce th...Melina wood torrefied at 260℃ for 60 min was agglomerated with lean grade coal fines into composite briquettes using pitch as binder.Torrefied biomass(3%-20%)and coal fines(80%-97%)were blended together to produce the composite briquettes under a hydraulic press(28 MPa).The briquettes were cured at 300℃.Density,water resistance,drop to fracture,impact resistance,and cold crushing strength were evaluated for the composite briquettes.The proximate,ultimate,and calorific value analyses were carried out according to different ASTM standards.Microstructural studies were carried out using scanning electron microscope and electron probe microanalyzer equipped with energy dispersive x-ray.Fourier Transform Infrared Spectrophotometer(FTIR)was used to obtain the functional groups in the raw materials and briquettes.The density of the composite briquettes ranged from 0.92 to 1.31 g/cm^(3) after curing.Briquettes with<10%torrefied biomass has good water resistance index(>95%).The highest cold crushing strength of 4 MPa was obtained for briquettes produced from 97%coal fines and 3%torrefied biomass.The highest drop to fracture(54 times/2 m)and impact resistance index(1350)were obtained for the sample produced from 97%coal and 3%torrefied biomass.The fixed and elemental carbons of the briquettes showed a mild improvement compared to the raw coal.The peaks from FTIR spectra for the briquettes shows the presence of aromatic C=C bonds and phenolic OH group.The composite briquettes with up to 20%torrefied biomass can all be useful as fuel for various applications.展开更多
Sawdust was subjected to torrefaction in a "semi-batch" slot-rectangular spouted bed (SRSB) reactor at temperatures from 240 to 330℃ and biomass feed rates from 220 to 710g/h.Stable spouting of the sawdust ...Sawdust was subjected to torrefaction in a "semi-batch" slot-rectangular spouted bed (SRSB) reactor at temperatures from 240 to 330℃ and biomass feed rates from 220 to 710g/h.Stable spouting of the sawdust was achieved in the slot-rectangular spouted bed,although the pressure drop across the reactor was observed to oscillate.Compared to the biomass feed rate,the temperature had a greater effect on the biomass weight loss and energy yield.Increases in temperature were found to promote weight loss of the sawdust while decreasing the energy yield.The main solid product was the torrefied sawdust,which remained in the SRSB reactor and was captured by a cyclone.The ratio of the torrefied biomass removed by the cyclone to the total torrefied biomass increased along with both the feed rate and temperature.After undergoing torrefaction,6.7%-39.2% of the original sawdust mass was lost while 67.4%-98.7% of its energy was retained.The torrefied sawdust had a higher carbon content but less oxygen,hydrogen and volatiles,along with a greater higher heating value and increased density compared to the raw sawdust.The size of the sawdust particles also decreased markedly during the torrefaction process.展开更多
Overwintering cattle on pastures in many areas can damage the pasture and lead to impaired water quality. During these times, use ofa woodchip heavy-use area （HUA） presents advantages such as a soft, supportive, and...Overwintering cattle on pastures in many areas can damage the pasture and lead to impaired water quality. During these times, use ofa woodchip heavy-use area （HUA） presents advantages such as a soft, supportive, and dry toot surface for animals and protection of the pasture and pasture soils. However, woodchip HUAs can also be a centralized source of high nutrient loads due to their drainage outflows. A column study was conducted to assess the nutrient load reduction potential of： 1 ） six types of wood media （including torrefied wood media and biochar） that could be used in a woodchip HUA versus a gravel control, and 2） providing a 48 h retention time within the wood media to enhance nitrogen removal through denitrification. The woody media provided significant liquid waste volume reduction compared to the gravel in simulated events （53%-61% vs. 39% reductions, respectively）, and there may be additional liquid storage capacity in the woodchips not utilized during these rapid events. Substantial total nitrogen removal by the wood treatments （mean removal efficiencies 〉 50%） was observed across the sinmlated events, although nitrate leaching also occurred. Nitrate removal was enhanced during the 48 h retention test which showed removal was governed by availability of labile carbon （i.e., fresh woodchips exhibited 〉 70% nitrate removal）. The retention test also indicated biochar mixtures provided some of the best total phosphorus removal, but the greatest benefits across all parameters was provided by the Mixed Hardwood treatment.展开更多
文摘Gasification efficiency is an important factor that determines the actual technical operation as well as the economic viability of using a gasifier system for energy production. In this study, the impact of the physical properties of torrefied bagasse and the influence of gasifier design and operating variables were investigated in a computer simulated downdraft gasification system. Results obtained from the study indicated an interrelationship between feedstock characteristics, especially with regard to feed size, design variables such as throat angle and throat diameter as well as gasifier operating conditions such as temperature of input air and feed input. These variables influenced the efficiency of the gasification process of sugarcane bagasse because of increased enhancement of combustion zone reactions, which liberated huge amount of heat that led to a rise in the temperature of the gasification process. This condition also created increased tar cracking within the gasification system, contributing to reduction in the overall yield of tar.
基金This research was funded by The World Academy of Science(TWAS),FR:3240287331,Italy and The Council of Scientific and Industrial Research(CSIR FUND:P-81-1-09),India.
文摘Melina wood torrefied at 260℃ for 60 min was agglomerated with lean grade coal fines into composite briquettes using pitch as binder.Torrefied biomass(3%-20%)and coal fines(80%-97%)were blended together to produce the composite briquettes under a hydraulic press(28 MPa).The briquettes were cured at 300℃.Density,water resistance,drop to fracture,impact resistance,and cold crushing strength were evaluated for the composite briquettes.The proximate,ultimate,and calorific value analyses were carried out according to different ASTM standards.Microstructural studies were carried out using scanning electron microscope and electron probe microanalyzer equipped with energy dispersive x-ray.Fourier Transform Infrared Spectrophotometer(FTIR)was used to obtain the functional groups in the raw materials and briquettes.The density of the composite briquettes ranged from 0.92 to 1.31 g/cm^(3) after curing.Briquettes with<10%torrefied biomass has good water resistance index(>95%).The highest cold crushing strength of 4 MPa was obtained for briquettes produced from 97%coal fines and 3%torrefied biomass.The highest drop to fracture(54 times/2 m)and impact resistance index(1350)were obtained for the sample produced from 97%coal and 3%torrefied biomass.The fixed and elemental carbons of the briquettes showed a mild improvement compared to the raw coal.The peaks from FTIR spectra for the briquettes shows the presence of aromatic C=C bonds and phenolic OH group.The composite briquettes with up to 20%torrefied biomass can all be useful as fuel for various applications.
文摘Sawdust was subjected to torrefaction in a "semi-batch" slot-rectangular spouted bed (SRSB) reactor at temperatures from 240 to 330℃ and biomass feed rates from 220 to 710g/h.Stable spouting of the sawdust was achieved in the slot-rectangular spouted bed,although the pressure drop across the reactor was observed to oscillate.Compared to the biomass feed rate,the temperature had a greater effect on the biomass weight loss and energy yield.Increases in temperature were found to promote weight loss of the sawdust while decreasing the energy yield.The main solid product was the torrefied sawdust,which remained in the SRSB reactor and was captured by a cyclone.The ratio of the torrefied biomass removed by the cyclone to the total torrefied biomass increased along with both the feed rate and temperature.After undergoing torrefaction,6.7%-39.2% of the original sawdust mass was lost while 67.4%-98.7% of its energy was retained.The torrefied sawdust had a higher carbon content but less oxygen,hydrogen and volatiles,along with a greater higher heating value and increased density compared to the raw sawdust.The size of the sawdust particles also decreased markedly during the torrefaction process.
文摘Overwintering cattle on pastures in many areas can damage the pasture and lead to impaired water quality. During these times, use ofa woodchip heavy-use area （HUA） presents advantages such as a soft, supportive, and dry toot surface for animals and protection of the pasture and pasture soils. However, woodchip HUAs can also be a centralized source of high nutrient loads due to their drainage outflows. A column study was conducted to assess the nutrient load reduction potential of： 1 ） six types of wood media （including torrefied wood media and biochar） that could be used in a woodchip HUA versus a gravel control, and 2） providing a 48 h retention time within the wood media to enhance nitrogen removal through denitrification. The woody media provided significant liquid waste volume reduction compared to the gravel in simulated events （53%-61% vs. 39% reductions, respectively）, and there may be additional liquid storage capacity in the woodchips not utilized during these rapid events. Substantial total nitrogen removal by the wood treatments （mean removal efficiencies 〉 50%） was observed across the sinmlated events, although nitrate leaching also occurred. Nitrate removal was enhanced during the 48 h retention test which showed removal was governed by availability of labile carbon （i.e., fresh woodchips exhibited 〉 70% nitrate removal）. The retention test also indicated biochar mixtures provided some of the best total phosphorus removal, but the greatest benefits across all parameters was provided by the Mixed Hardwood treatment.
