Energy Saving Optimization Research On Modelling And Thermal Coupling Technique Application Of Air Separation Unit In Refining Process

Air separation is the process of separating air to acquire high-purity industrial gases such as oxygen,nitrogen,and argon.It is a pivotal industry in the national economy.Air separation process is widely used in various industrial fields such as petroleum,chemical industry,metallurgy,electronics,energy,aerospace,medical care,and some emerging industries such as IGCC and LNG,etc.However,under the current era of rapid economic development background,the production capacity of air separation industry and its inherent high energy consumption characteristics have significantly constrain the pace of its progress,and it has also highlighted the great practical significance of energy conservation and optimization research in this field.In the paper,the mechanism and simulation model of the air separation device in refining process of a company in Jiujiang were respectively conducted,followed by the analysis and optimization of the device’s operating and structural parameters through certain measures.Apart from that,based on in-depth research of the current thermal coupling distillation technique which possesses the highest energy efficiency,the external condenser and reboiler were applied to this device to accomplish thermal coupling between certain column stages.The optimized energy consumption analysis results further verified the huge energy saving potential encompassed by this technique,with which theoretical basis and support for plant’s upgrade in the near future are provided as well.The main research contents and achievements in this paper are listed as follows:(1)According to the actual process of the air separation plant of one company in Jiujiang,firstly,Aspen Plus process simulation software was utilized to establish a process simulation model of the entire plant,followed by the simulation of actual working conditions.Then,for operating parameters such as feed air,distillated liquid nitrogen,oxygen-enriched liquid production,extracted nitrogen quantity,etc.and structural parameters such as air compressor and expander outlet pressure,liquid-air feed position,nitrogen product extraction position,etc.sensitivity analysis measures were conducted to analyze and optimize corresponding parameters respectively.Through the optimization results,theoretical optimal operational values were obtained with respect to relative parameters.Under present working conditions,the production potential was extracted and energy consumption was reduced as well.(2)Established a more accurate mechanism model based on MATLAB with respect to the air separation process to further reduce total energy consumption,and solved it by adopting autonomous programming approach.At the same time,on the basis of this model,the interior point algorithm was utilized to optimize and analyze the fundamental variables of the device,which further facilitated its productive capacity.(3)On the basis of in-depth research on thermal coupling technique,corresponding energy-saving optimization analysis of the application of this technique was conducted on current air separation operation unit(by installing peripheral intermediate condenser and reboiler).The comparisons between the experimental outcomes and optimization results of the two modeling methods further validated the huge potential embraced by this technique in the domain of energy saving and reduction.