Synthesis Of Indirect Work Exchange Networks Based On Superstructure Method

With the rapid development of the world and the rapid development of China's economy,contemporary society is gradually building a different energy system from the past.An important strategic concept is energy-conservation and emission-reduction,whose main characteristics include affordability,reliability and sustainability.Momentum(work)is one of the high-quality energy sources in the research of principles of chemical engineering,but the research of work exchange network is still in its infancy.In this paper,a new superstructure model is proposed for indirect work network,which is widely used in work network.Based on this superstructure model,indirect work exchange network is synthesized.The problems of streams matching,energy exchange and pressure constraints are mainly solved.(1)In order to solve the problem of unclear matching of streams in indirect work exchange networks,a superstructure model considering the potential matching possibility of all streams is established.Aiming at the minimum annual total cost,a mixed integer nonlinear programming model is proposed to synthesize the indirect work exchange networks.In this structure,based on the relationship of energy exchange constrained by the matching of high and low pressure flows,bypass and operation are optimized,and the thermal integration part is simplified to some extent.Finally,an example is solved to verify the effectiveness and feasibility of this method.(2)In order to solve the complex non-convex nonlinearity among pressure,flow and temperature in the indirect work exchange network,this paper propose a linear fitting strategy based on the actual operating performance curves of compressors and turbines.The linear relationship between the corrected pressure and the corrected flow rate of high and low pressure streams is obtained.The optimal work exchange network structure is obtained by combining the stream matching identification method proposed in the superstructure model.Furthermore,sensitivity analysis of SSTC work exchanger shaft speed is carried out to explore the coupling relationship between different shaft speed and work exchange network structure optimization.Finally,a example is given to illustrate the advantages of the proposed method in terms of economy and energy recovery.The superstructure model constructed in this paper also reduces the annual total cost on the basis of building streams matching,considering pressure operation and improving energy utilization efficiency.It provides an effective theoretical basis for energy saving,emission reduction and cost control in actual chemical engineering projects.