Petrochemical plants are chemical industries that produce chemical products from petroleum and natural gas. Its production process has three characteristics in heat energy utilization: first, it needs a large number of steam of different quality to provide heat and as raw materials for production; secondly, it needs a large number of driving power to compress gas and pump fluid; thirdly, it has a large number of production process heat to recover heating water and generate steam, among which compressed gas consumes a lot of energy. Chemical plants need a steam power system which is closely matched with the production process and adapts to the production demand, i.e. steam system, to supply heat for production process and steam as raw material, as well as to supply steam to each steam turbine to generate power drive pump.