Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting inter...Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting internals particularly designed greatly improved the heat transfer inside coal bed and raised the yield of tar production.Reducing pressure further facilitated the production of tar through its suppression of secondary reactions occurring in the reactor. The absolute increase in tar yield reached 3.33 wt% in comparison with the pyrolysis in the reactor without internals under atmospheric pressure. The obtained tar yield in the reactor with internals under reduced pressure was even higher than the yield of Gray–King assay. Through experiments in a laboratory fixed bed reactor, it was also clarified that the effect of reducing pressure is related to volatile release rate in pyrolysis. It did not obviously vary tar yield at pyrolysis temperatures below 600 ℃, while the effect was evident at 650 and 700 ℃ but became limited again above 800 ℃. Under reduced pressure the produced tar contained more aliphatics and phenols but less aromatics.展开更多
Returning biochar to soil is a heavily researched topic because biochar functions well for soil improvement. There is a significant loss of nutrients, which occurs during biochar preparation before biochar is returned...Returning biochar to soil is a heavily researched topic because biochar functions well for soil improvement. There is a significant loss of nutrients, which occurs during biochar preparation before biochar is returned to soil,thereby seriously undermining biochar＇s efficacy. Therefore, the transformation mechanisms of biochar p H,mass, nutrients and metals during pyrolysis under different atmospheres and temperatures were studied such that the best method for biochar preparation could be developed. Several conclusions can be reached：（1） a CO2 atmosphere is better than a N2 atmosphere for biochar preparation, although preparation in a CO2 atmosphere is not a common practice for biochar producers;（2） 350 ℃is the best temperature for biochar preparation because the amount of nutrient loss is notably low based on the premise of straw transferred into biochar; and（3） transforming mechanisms of pH, N, P and K are also involved in the biochar preparation process.展开更多
基金Supported by the National Natural Science Foundation of China(21376250)National Basic Research Program of China(2014CB744303)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA07010100)
文摘Pyrolysis of Shenmu coal was performed in fixed-bed reactors indirectly heated by reducing operating pressure and mounting internals in the reactor to explore their synergetic effects on coal pyrolysis. Mounting internals particularly designed greatly improved the heat transfer inside coal bed and raised the yield of tar production.Reducing pressure further facilitated the production of tar through its suppression of secondary reactions occurring in the reactor. The absolute increase in tar yield reached 3.33 wt% in comparison with the pyrolysis in the reactor without internals under atmospheric pressure. The obtained tar yield in the reactor with internals under reduced pressure was even higher than the yield of Gray–King assay. Through experiments in a laboratory fixed bed reactor, it was also clarified that the effect of reducing pressure is related to volatile release rate in pyrolysis. It did not obviously vary tar yield at pyrolysis temperatures below 600 ℃, while the effect was evident at 650 and 700 ℃ but became limited again above 800 ℃. Under reduced pressure the produced tar contained more aliphatics and phenols but less aromatics.
基金Supported by the National Natural Science Foundation of China(No.41571283)
文摘Returning biochar to soil is a heavily researched topic because biochar functions well for soil improvement. There is a significant loss of nutrients, which occurs during biochar preparation before biochar is returned to soil,thereby seriously undermining biochar＇s efficacy. Therefore, the transformation mechanisms of biochar p H,mass, nutrients and metals during pyrolysis under different atmospheres and temperatures were studied such that the best method for biochar preparation could be developed. Several conclusions can be reached：（1） a CO2 atmosphere is better than a N2 atmosphere for biochar preparation, although preparation in a CO2 atmosphere is not a common practice for biochar producers;（2） 350 ℃is the best temperature for biochar preparation because the amount of nutrient loss is notably low based on the premise of straw transferred into biochar; and（3） transforming mechanisms of pH, N, P and K are also involved in the biochar preparation process.
