Control System Design Of Gas Station With Natural Gas Revamping For A Steel Plant

In the iron and steel industries, gases with different calorific valve will be mixed and pressurized, then to be sent to subsequent gas users. The control target for mixing and pressurizing of the gas is to ensure the stability of the calorific value and pressure of the gas.The gas mixing is a complicated process and influenced by numerous factors, which needs us to find effective control method urgently.The gas mixing and pressurization process features with strong coupling, non-linearity, powerful interference and uncertainty, therefore, the tradition reheating control arithmetic cannot resolve the problem.According to the control requirements of gas mixing and pressurization process in actual industrial production, we had proposed the calorific value and pressure decoupling control loop for the first mixing process(COG+BFG).We will use the NG(natural gas) instead of COG if it is not enough. Once the NG(natural gas) is increased, the NG and COG will be displaced proportionally With the increase of the NG(natural gas), the COG will be displaced proportionally and total flow works with cross limiting control. We design a DCS system, and also a man-machine interface system based on actual process requirements. We had improved it based on actual operation.This system has been applied in steel industry. On the basis of actual industrial production, we can know that it is feasible, advanced, steady-going and reliable, restraining calorific value and pressure, which has producedgreat economic returns and social benefits.