Alternative Integration Strategies For Energy Recovery And Simultaneous Separation Of Coal And Oil Sands Pyrolysis Products

With the increasing difficulty of exploration of conventional petroleum resources,focus has turned into effective and clean utilization of non-conventional resources,such as coal and oil sands.Compared with other conversion refining methods,pyrolysis is the most efficient way of thermal energy conversion with high valued products and less pol-lutants.The problems of traditional separation process appear gradually,including diffi-culty in separation,challenge of wastewater treatment and energy waste.In this work,an integrated process followed by the pyrolysis steam with an initial fractionation column of pyrolysis products based on the pyrolysis stream energy recovery unit is proposed and analyzed.In the first part,it is significant to simplify the components of the pyrolysis steam of coal and oil sands by real components combining with pseudo component in the simula-tion for effective characterization of pyrolysis steam to determine feeding conditions.Economic functions of separation of pyrolysis products were established.In the second part,energy recovery distillation(type I)and energy recovery distilla-tion with water washing(type II)were established.A design procedure for type I and II should optimize the total stage number,side withdrawal location,the pump-arounds flows,duties,and the flow rate of stripping stream.The procedure produced is an effi-cient method to achieve the optimum value.Compared with traditional ammonia spray process,significant decline of 56.22%and 48.20%in total annual cost(TAC)can be ob-tained by the effective integration of separation technology.Furthermore,based on the using of novel integration technology,the cost will be decreased from 5.5$/t to 3.61$/t and 3.61$/t in the oil sands refining process consist of the pyrolysis,recovery and separa-tion processes.Type II performs better than type I at a large vapor load.In the third part,an integrated process for crude gas with main fractionation column via pump-around refluxes and stripping stream was established.A method is proposed for the process analysis procedure of main fractionation column to optimize for an economi-cal objection function,such as total number of stage,side withdraw location,pump-arounds and strippers.The wash oil,I anthracene oil and II anthracene oil side withdraw locations equal to 18,28 and 37 in main fractionation column with 45 stages.And economical function reach maximum when the duty of bottom pump-around,II an-thracene oil pump-around,I anthracene oil pump-around,wash oil pump-around and top pump-around are set at-7.6,-2.2,-1.2,-0.7 and-1.5Gcal/h.The innovatory processes,leads to same separation capacity of products as traditional process with the high level energy recovery.The main fractionator condensation process recovers 23387 kg/h of saturated steam,and produces 16322 kg/h of high pressure(600 psig)saturated steam.Compared with traditional process,significant decline from 25.95×10~5$to 8.97×10~5$in total annual cost(TAC).The energy recovery distillation process proposed in this paper can effectively solve the problems of oil-water separation,wastewater treatment and energy recovery in tradi-tional spraying process.It lays a theoretical foundation for the industrial application of coal and oil sands pyrolysis process.