The Calculation Of Downstream Three-Effect Steam Jet Heat Pump Evaporation System

Steam jet heat pump evaporation is a new type of high efficient energy-saving technology. But the system with steam ejector will be more complex and difficult to calculate the parameters. Currently, it was focuses on calculation and optimization of ordinary multi-effect evaporation system. It was relatively little which was studied on calculation of complex multi-effect steam jet heat pump evaporation system. Mostly research of all the complex system were about desalination, but the desalination system with the heat pump evaporation is not fully adapted to other industries. Therefore, explore the efficient and accurate calculation algorithm to the design of complex multi-effect steam jet heat pump evaporation system which is widely used in chemical, pharmaceutical, food and other fields is particularly important.According to the downstream three-effect steam jet heat pump evaporation system, the mathematical model of calculate the entrainment ratio on basis of Sokolov method is established, and the mathematical model of conventional design of downstream three-effect steam jet heat pump evaporation system with condensate flashing is established aslo, the model of the system is solved by MATLAB toolbox fsolve function and the conventional design parameters are achieved.In order to optimize and improve the conventional design, the system is optimized with a goal that is annual cost. According to analysis the factors which can influence the annual cost, decision variables are determined which is the first effect of heating steam temperature T1, the first effect evaporation temperature T2, the third effect evaporation temperature T4and heat transfer temperature difference of each effect Δt1(besides the first effect). The MATLAB toolbox fmincon function is selected as a method to solved the multivariable constrained nonlinear programming problem, it can quickly and accurately obtain the optimal solution.The calculate results show that conventional and optimum design model of downstream three-effect steam jet heat pump evaporation system with condensate flashing have good universality. The solving methods have advantages of short computing time and good convergence. Considering the condensate flashing and optimized T1,T2,T4and Δti, the energy-saving effect is remarkable. A multi-effect evaporation design software is developed which have advantages like friendly interface, easy to use, calculate accurately and so on.