The Improvement Study Of Active Safe Protection System Of Large Oil Storage Tank

Large type oil storage tank active safety system to achieve the fire prevention based on the oil and gas concentration control of large type external floating roof tank.Explosion hazard caused by lightning,static electricity and fire could be effectively prevented in the procedure of oil storage and transportation could be actively prevented by the closed-loop control method with the combination of real time gas analysis system and active inert gas protection system of this system.Presently,the system has been widely used in Dalian and other places,and has obtained the good protection effect.According to the operating data analysis of the engineering application instances in recent years,under the condition of full tank,large type oil tank has the problem of long period oil and gas concentration exceeding.The frequent nitrogen injection of protection system can not guarantee the oil tank stay in the safe condition and also cause the energy waste at the same time.This article put forward a new safe protection method of “a combination of dredge and block”.The error of random interference is overcome andthe anti-interference ability is enhance d by using digital filtering algorithm in the filter design.The main content of this study is to improve the original PLC control system.The study include: the control requirement shall be analyze according to the process flow and the control mission shall be ensured to accomplish the workflow design of the new system;Determine the required user input devices,output devices,and controlled by the output device driver object;Estimate the I/O number of PLC,analyze the signal relation and signal property between control object and PLC;control the precision to estimate the user memory capacity of PLC according to the complexity degree of control requirement;PLC shall be selected according to the type and number of input and output,control method and speed,control precision and resolution and user process capacity;the program of new system shall be programmed by using the S7-200 special programming software,including the design of ladder diagram,written statements table and draw flow diagram of control system.The design of the upper computer system is completed by using the force control configuration software.