In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare th...In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare the nature of their pyrolysis. In this study, the experiment was carried out through a lab tube furnace, at a heating rate of 10 ~C/min, and the gas was analyzed and compared, which was collected at different temperatures. The results show that： in the pyrolysis temperature of 550-850 ℃, the semi-coke yield of briquette is 2%-6% higher than lignite, the tar yield of briquette is 2%-3% higher than lignite and the gas yield of briquette is 4%-9% less than lignite. The time required for complete release of the briquette is about 20 min less than lignite. The components in the pyrolysis gas of lignite and its briquette are the same, and their variation with the pyrolysis temperature is similar.展开更多
Currently, thermal decomposition of hydrocarbons for the production of basic petrochemicals(ethylene, propylene) is carried out in steam-cracking processes. Aside from the conventional method, under consideration are ...Currently, thermal decomposition of hydrocarbons for the production of basic petrochemicals(ethylene, propylene) is carried out in steam-cracking processes. Aside from the conventional method, under consideration are alternative ways purposed for process intensification. In the context of these activities, the method of hightemperature pyrolysis of hydrocarbons in a heat-carrier flow is studied, which differs from previous ones and is based on the ability of an ultra-short time of feedstock/heat-carrier mixing. This enables to study the pyrolysis process at high temperature(up to 1500 K) at the reactor inlet. A set of model experiments is conducted on the lab scale facility. Liquefied petroleum gas(LPG) and naphtha are used as a feedstock. The detailed data are obtained on temperature and product distributions within a wide range of the residence time. A theoretical model based on the detailed kinetics of the process is developed, too. The effect of governing parameters on the pyrolysis process is analyzed by the results of the simulation and experiments. In particular, the optimal temperature is detected which corresponds to the maximum ethylene yield. Product yields in our experiments are compared with the similar ones in the conventional pyrolysis method. In both cases(LPG and naphtha), ethylene selectivity in the fast-mixing reactor is substantially higher than in current technology.展开更多
Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat.This study focused on the disintegration characteristics under laboratory condi...Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat.This study focused on the disintegration characteristics under laboratory conditions of typical purple mudstone from the Tuodian group of Jurassic red beds(J3t) in Tuodian Town,Shuangbai county,Yunnan Province of southern China.The fresh mudstone was subjected to alternating applications of water,heat and hydrothermal interaction during five treatments:wetting-drying(WD),saturation(ST),refrigeration-heating(RH),a combination of wetting-drying and refrigeration-heating(WDRH),and a combination of saturation and refrigeration-heating(STRH).Each treatment was run in twenty-four cycles.The results showed that there are three types of disintegration:collapsing disintegration,exfoliation disintegration and imperceptible disintegration.The cumulative disintegration rate(percentage of cumulative disintegrated mass to the initiative sample mass passed through a 2 mm sieve) produced a 'S'-shape function when related to treatment cycle time and closely fit a logistic model(R2 > 0.99).The rank order of the cumulative disintegration rate resulting from the five treatments was as the following:WDRH > STRH > ST > WD > RH.Because of alternating periods of moisture and dryness,WD caused the most disintegration,while RH alone resulted in imperceptible disintegration.Additionally,there was a negative correlation between the disintegration rate of each treatment cycle(percentage of disintegrated mass to the treated sample mass) and treatment cycle number.There was a positive correlation between this rate and temperature change under moist conditions,indicating that a change in temperature greatly accelerates the disintegration of parent rock when water was supplied.展开更多
文摘In this experiment, lignite was refined and processed through binderless briquette preparation process from low-rank coal and became briquette. Then, lignite and its briquette were pyrolysed as materials to compare the nature of their pyrolysis. In this study, the experiment was carried out through a lab tube furnace, at a heating rate of 10 ~C/min, and the gas was analyzed and compared, which was collected at different temperatures. The results show that： in the pyrolysis temperature of 550-850 ℃, the semi-coke yield of briquette is 2%-6% higher than lignite, the tar yield of briquette is 2%-3% higher than lignite and the gas yield of briquette is 4%-9% less than lignite. The time required for complete release of the briquette is about 20 min less than lignite. The components in the pyrolysis gas of lignite and its briquette are the same, and their variation with the pyrolysis temperature is similar.
文摘Currently, thermal decomposition of hydrocarbons for the production of basic petrochemicals(ethylene, propylene) is carried out in steam-cracking processes. Aside from the conventional method, under consideration are alternative ways purposed for process intensification. In the context of these activities, the method of hightemperature pyrolysis of hydrocarbons in a heat-carrier flow is studied, which differs from previous ones and is based on the ability of an ultra-short time of feedstock/heat-carrier mixing. This enables to study the pyrolysis process at high temperature(up to 1500 K) at the reactor inlet. A set of model experiments is conducted on the lab scale facility. Liquefied petroleum gas(LPG) and naphtha are used as a feedstock. The detailed data are obtained on temperature and product distributions within a wide range of the residence time. A theoretical model based on the detailed kinetics of the process is developed, too. The effect of governing parameters on the pyrolysis process is analyzed by the results of the simulation and experiments. In particular, the optimal temperature is detected which corresponds to the maximum ethylene yield. Product yields in our experiments are compared with the similar ones in the conventional pyrolysis method. In both cases(LPG and naphtha), ethylene selectivity in the fast-mixing reactor is substantially higher than in current technology.
基金supported by National Natural Science Foundation of China (Grant No.40971168)National Basic Research Program of China (973 Program) (Grant No. 2007CB407206)
文摘Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat.This study focused on the disintegration characteristics under laboratory conditions of typical purple mudstone from the Tuodian group of Jurassic red beds(J3t) in Tuodian Town,Shuangbai county,Yunnan Province of southern China.The fresh mudstone was subjected to alternating applications of water,heat and hydrothermal interaction during five treatments:wetting-drying(WD),saturation(ST),refrigeration-heating(RH),a combination of wetting-drying and refrigeration-heating(WDRH),and a combination of saturation and refrigeration-heating(STRH).Each treatment was run in twenty-four cycles.The results showed that there are three types of disintegration:collapsing disintegration,exfoliation disintegration and imperceptible disintegration.The cumulative disintegration rate(percentage of cumulative disintegrated mass to the initiative sample mass passed through a 2 mm sieve) produced a 'S'-shape function when related to treatment cycle time and closely fit a logistic model(R2 > 0.99).The rank order of the cumulative disintegration rate resulting from the five treatments was as the following:WDRH > STRH > ST > WD > RH.Because of alternating periods of moisture and dryness,WD caused the most disintegration,while RH alone resulted in imperceptible disintegration.Additionally,there was a negative correlation between the disintegration rate of each treatment cycle(percentage of disintegrated mass to the treated sample mass) and treatment cycle number.There was a positive correlation between this rate and temperature change under moist conditions,indicating that a change in temperature greatly accelerates the disintegration of parent rock when water was supplied.
