Study On Energy Saving Process Of Styrene Plant And Effective Energy Analysis

The current high energy consumption of styrene production equipment has seriously affected the production capacity of the equipment.In order to reduce the energy cost of the device,improve the capacity and efficiency of the device,and optimize the existing styrene production process,multi-effect distillation,mechanical vapor recompression(MVR)heat pump distillation and organic Rankine cycle(ORC)low-temperature waste heat power generation are introduced.The energy-saving research of styrene production equipment is carried out through various methods.In this paper,Numerical simulations were performed by Aspen Plus and Aspen Energy Analyzer software environment under the Peng-Rob thermodynamic model to modify the binary interaction parameters,which improve the accuracy of the simulation.Taking the annual total cost(ATC)as the evaluation index of the distillation process,two more economical separation sequences were determined,and the conventional distillation process,the multi-effect distillation process,the MVR heat pump distillation process and the optimization of the heat exchange network were studied respectively.On this basis,the low-temperature waste heat which has not been used in the device is fully utilized by ORC low-temperature waste heat power generation technology,and then the ORC coupled MVR heat pump distillation process was proposed.The research results were as follows:(1)By strictly changing the feed water-to-hydrocarbon ratio to investigate the relationship between the raw material conversion rate and energy consumption,the optimal water-to-hydrocarbon ratio for styrene synthesis was 1:1.02.(2)With the minimum ATC as the objective function,two more economical conventional distillation process routes were obtained,and then sensitivity analysis was used to determine the best operating parameters of the distillation process.(3)After the optimization of the conventional distillation process,the multi-effect distillation technology was used to study the multi-effect distillation process.The results showed that the use of multi-effect distillation has reduced the ATC of separation sequence 1 and 2 by 21% and 20.6%,respectively.(4)The application of the MVR heat pump distillation process has make the overall optimization process more economical.Compared with the conventional distillation process,the ATC of the separation sequence 1 and 2was reduced by 37.3% and 39.6%,respectively.On the basis of the MVR heat pump distillation process,the whole process with the heat exchange network was optimized using pinch point analysis technology,and the optimal heat exchange network of the utilities were obtained.The research results showed that the styrene production device can save energy by 42.0%,save ATC by39.5% after optimization,and the entire thermodynamic efficiency has been significantly improved.(5)For the low-temperature waste heat in the recovery device,the ORC low temperature waste heat power generation technology was applied,and the electric energy generated by the ORC power generation technology was applied to the compressor.The research results showed that the novel process can further save ATC about by 5.4% and increases the overall thermodynamic efficiency to 9.7%.In all examples,the MVR heat pump distillation process coupled with ORC methodology is able to outperform previous studies regarding TAC,proving a practicable alternative to methods that are currently applied in the literature.