Research On Monitor And Control System Of Heat Tracing Pipeline Network

In petrochemical enterprises, the material is mostly transported through pipeline. To ensure the material is able to run fluently in pipeline, it always needs to heat the pipeline which namely heat tracing. Heat tracing with outside heat pipeline is the common heat tracing method, which layouts another pipeline along the material pipeline, and the high temperature water or steam is used as heating medium. The heating temperature and flow of heating medium can be adjusted according to the heating requirement. Current adjustment ways of tracing heat are usually simple qualitative adjustment mode, which only adjust the heating temperature, and the flow of the heating medium does not change during the heating process of pipe network. It can guarantee the heating demand, but it always leads to a waste of energy and causes the uneven heat between the heat tracing branches. Therefore, in order to achieve energy conservation and emissions reduction, reduce energy consumption and optimize thermal environment, this paper studied the optimization control method of the heating pipe network.In this paper, the heat supply system of heat tracing network is divided into two levels, namely the first heating and the secondary heating network. The heating medium is heated in heat source and then transported to sub stations through the first heating network, and sub stations transport it to heating pipelines according to flow distribution. Different with the simple qualitative adjustment mode, the qualitative adjustment is combined with quantity adjustment in this paper. The secondary heating network forecasts water temperature according to the change of outdoor temperature and formulates the heating curve. By adjusting the quantity of heat source heating to adjust the water temperature of the secondary heating network, the goal of on-demand heating is achieved. During the heating process of heat tracing network, because the number of heating branches is large and the geographical environment factors is different between them, the heat is uneven among them. So different heating branch can adjust the volume of heating through the autonomic regulation branch valve opening.In this paper, the adjustment method of branches is based on the backwater temperature. Based on heat transfer characteristics of heat tracing system, heating medium can obtain enough heat if the backwater temperature in branches reaches technical index, and the method based on the backwater temperature is the most intuitive and effective adjustment method. By monitoring the backwater temperature in branches, and adjusting the temperature control valve opening with the closed loop feedback method, the temperature of return water reaches technical index. Because the heat transfer process of heat tracing system has the characteristics of large lag and large inertia, strong coupling, conventional classical control method is unable to achieve good control effect. In this paper, we designed the fuzzy controller and determined the control rules based on fuzzy control algorithm, and simulated the effect of fuzzy control, then got the corresponding temperature curve. Compared with the traditional PID control, the control effect of the fuzzy controller designed in this paper is proved.