| Biomass pyrolysis-coupled bio-oil upgrading technology can transform straw into high-value liquid fuel.It is one of the most developmental thermochemical conversion technologies,which can achieve efficient energy utilization of straw.In this paper,the typical straw waste corn stover in China is taken as the research object,and the simulation research on biomass solid heat carrier method pyrolysis system,pyrolysis steam stage condensation system and bio-oil upgrading fuel oil system is carried out to provide guidance for the optimization of the process performance of biomass pyrolysis to improve fuel oil.The energy analysis of the pyrolysis liquefaction system of the biomass heating system with ceramic ball circulation heating down tube was carried out,and the effects of raw material moisture content and heat carrier to feed material mass flow ratio（MR）on energy loss and energy efficiency of the system were explored,and the energy flow variation law of pyrolysis system based on solid heat carrier method was revealed.Under the given operating conditions（the temperature of the drying,pyrolysis and combustion reactors are 90,500 and 750℃;the outlet temperature of the bio-oil is 25℃;the reflux ratio of the bio-oil is 0.6;the temperature of the heat carrier is 520℃,the MR is 15:1）,the energy consumption of the drying,pyrolysis,and combustion units is 0.1,1.3 and 0.7MJ/kg,respectively.As the water content of the raw material decreases from 20%to 5%,the energy consumption for drying is reduced from 0.13 to 0.12 MJ/kg,the energy consumption for pyrolysis is reduced from 1.4 to 0.8 MJ/kg,and the energy consumption for combustion is reduced from 0.8 to 0.6 MJ/kg.As the MR increased from 5:1 to 15:1,the combustion energy efficiency increased from 39%to 98%.Continue to increase the MR to 25:1 and the combustion energy efficiency decreased to 88%.The staged condensation process is a key part of bio-oil treatment,which helps to improve the adaptability of bio-oil to subsequent catalytic hydrogenation,catalytic cracking and other upgrading processes.Carried out three-stage heat exchanger type（abbreviated as THC）and one-stage spray-two-three-stage heat exchanger type（abbreviated as TCC）two pyrolysis steam stage condensation model simulation studies,and analyzed three working conditions（The condensing temperature of the first,second and third stage of the first working condition is 100,60 and 25℃;the second working condition is 80,60 and 25℃;the third working condition is 80,25 and 0℃）for the influence of the condensation product distribution,and the exergy efficiency and exergy loss of the two condensation modes were investigated by exergy analysis method.Under the three working conditions,the internal exergy loss of the first,second and third levels of THC is 0.2,3.3×10-2and 0 MJ/kg,and TCC is 0.3,0.2 and 0 MJ/kg.the external exergy loss of the first,second and third levels of THC is 2.0×10-3,8.8×10-3and 0 MJ/kg,and the TCC is 0,8.8×10-3and 0 MJ/kg.Compared with THC,the exergy efficiency of the TCC system in the first stage condensation is 1.69%lower,and in the second and third stage condensation,the exergy efficiency is increased by 14.5%and 5.9%.Bio-oil graded modification and upgrading process for preparing fuel oil is established.The light components of bio-oil are converted into fuel oil by water phase reforming,water gas shift and Fischer-Tropsch synthesis.The heavy components are modified by water gas shift and hydrocracking.Coke produces syngas based on water gas shift and dry reforming gasification reforming.Relative to 1 kg of bio-oil,this graded upgrading system consumes 0.7 kg of coke and can produce 0.3,0.2 and 0.1 kg of gasoline,aviation fuel and diesel.The proportion of hydrocarbons in gasoline,diesel and aviation fuel is 84.7%,15.3%;84.9%,15.1%and 84.1%,15.1%.The economic analysis of biomass oil heat carrier method pyrolysis coupled catalytic upgrading to produce fuel oil system was carried out.The results show that The results show that the net present value is 1.36million yuan,the internal rate of return is 23%,and the investment recovery period is 4years when the system is built for 1 year,used for 10 years,and has a financial base rate of return of 10%.When the biomass processing capacity is 1170 tons/year,the system reaches the break-even point. |
