Temperature Measurement Point Analysis And Controllability Study Of Heat Exchanger Network Based On Complex Network Theory

The rapid development of the process industry has led to the increasing size and complexity of heat exchanger networks.The coupling between the various logistics is severe,and local temperature fluctuations are transmitted to the heat exchangers associated with them to interfere with the normal operation of the entire system.Therefore,it is of great significance to study how to properly set the temperature measurement point to monitor the temperature fluctuation in the heat exchange network and set the bypass to adjust the target temperature in time.Firstly,taking the heat exchanger as a node,abstracting the interference between heat exchangers into edges,constructing a complex network model.And then combining the "downstream path" theory to weight the network model,finally obtaining the directional weighting complex network model of the heat exchanger network.Secondly,based on the observation point deployment strategy of complex network propagation source location,a method for setting the temperature measurement point of heat exchanger network is proposed.Firstly,the Fast Newman algorithm is used to classify the above model,and then the complex network analysis software UCINET6.0 is used to calculate the centrality of the node.The top 20% of the nodes in each community are selected to set the temperature measurement points.Then,weigh the two factors of controllability and economy,and give two methods for determining the location of the bypass.When the controllability requirements are high,based on the controllability theory of complex network structure,a globally controllable bypass position determination method for heat exchanger networks is proposed.The algorithm not only realizes the global controllability of the heat exchange network by setting a minimum of bypass,but also optimizes the control performance of the heat exchange network.When the number of bypasses is limited,based on the theory of complex network target control,a bypass point determination method with controllable important nodes is proposed.Which can reduce the number of bypasses and save investment costs while ensuring that its important nodes are controllable.Finally,based on the control robustness analysis method of the minimum driving node of complex network,the control robustness of the heat exchanger network under four different attack modes is analyzed.The results show that the heat exchange network has certain robustness in single-node attack and partial-edge failure mode,and its controllability is gradually reduced.However,there is almost no robustness in the node and edge cascading failure mode,and its controllability shows a cliff-like decline.Which provides a theoretical basis for the controllability optimization of the heat exchanger network.Taking a large-scale heat exchange networks as an example,solve the temperature measurement points and bypass positions of the heat exchange network,and analyze its control robustness.Which verified the feasibility of the method.