生物质热解加氢制汽柴油系统的分析

Exergy analysis of transportation fuel production via biomass fast pyrolysis and hydroprocessing

基于生物质热解加氢制汽柴油系统的Aspen Plus模拟，分析了全系统碳氢氧元素的平衡转化过程，并基于[火用]理论对全系统及各单元进行了用能分析，研究了参数变化对系统[火用]效率的影响。结果表明：模拟条件下汽柴油产率为0．122kg／kg生物质（干基）；生物质碳的24．74％转化到汽柴油；转化到汽柴油的氢占实际总氢消耗的19．79％；加氢过程生物油氧38．2％以CO2脱除，其余以H2O脱除。全系统总[火用]效率（η＋）和产品[火用]效率（η-）分别为59．9％和32．8％；全系统[火用]损以内部不可逆[火用]损为主，比例达约30％，热解单元是全系统[火用]损最大的部位。热解适宜温度为450～550℃；重整适宜温度为750-800℃，且压力不宜过大；系统自供氢条件下，η＋和η-所能达到的最大值分别为63．1％和42．6％。

Based on the Aspen Plus simulation of transportation fuels （BTPF） production via biomass fast pyrolysis and hydroprocessing, both the flow balance of carbon, hydrogen and oxygen and the exergy analysis of BTPF production system were carried out. Moreover, the parameter sensitivity on the exergy efficiency was also studied. The results indicate that the yield of BTPF is 0. 122 kg/kg （dry biomass） and the atom utilization efficiency of carbon converting the biomass into BTPF reaches 24.74%, while 19.79% of the total consumed hydrogen is converted into BTPF. Nearly 38.2% of the total oxygen in bio-oil is removed as CO2, and the remaining eliminated in the form of H2O. The exergy efficiencies of the total system （η＋） is 59.9%, while the exergy efficiencies converting biomass into BTPF （η-） reaches 32.8%. The exergy loss of the whole system is mainly caused by the internal irreversibility, approaching nearly 30% and the largest exergy loss occurs in the pyrolysis subsystem. In addition, the pyrolysis temperature is proposed to be 500-550 ℃. Furthermore, the optimal reforming temperature is 750-800 ℃ and the reforming pressure should not be too large. The maximums of η＋ and η- can reach 63.1% and 42.6% respectively with self-supplied hydrogen.