Structure Optimization Of Heat Exchanger Network Based On Pseudo-temperature For Batch Processes

Batch processes take an increasing proportion of chemical production processes as market changes and new chemical products appear faster and faster. However, compared with continuous production processes, on the current, the researches on heat exchanger network for batch processes began much later, and there are still only a few of researches about them. Furthermore, the independence on time of batch plant account for the difficulty of dealing with it. In this context, this paper studies the structure optimization of heat exchange network for batch processes, on the basis of the heat exchanger network of batch processes based on the pseudo- temperature. The content of this paper is listed as follows:On the basis of the Time Slice Model, through the program of synthesizing the heat exchanger network by taking place the approach temperature with pseudo-temperature, the initial network with the minimum cost can be got, at the same time the heat exchanger area, the quantity of heat exchange and the heat transfer temperature difference in each time interval of the network. The thermal load loops can be found within each time interval of the direct heat exchanger network for batch processes. According to three rules put forward in this paper, including two rules applicable to both continuous and batch processes and one rule applicable to batch processes only, these heat load loops can be disconnected. The number of the units of the heat exchanger network can be reduced. The total cost of the ultimate network can be calculated, including the investment cost and the operation cost. Two examples are calculated getting results that the number of units and the total cost are both reduced. It shows the reliability of the procedures of batch direct heat exchanger network design and the validity of the method's effectiveness.