Research On The Automatic Control System Of Oil And Gas Emission Process Based On PLC

Oil and gas discharge and treatment, an energy-saving, environmentally friendly high technology, is still an emerging industry in China. An oil and gas discharge and treatment system program was initiated to investigate the auto-matic control system used for oil and gas discharge and treatment during transportation and storage of product oil in oil depots and refineries. This re-search involves the following design and investigations:1. A new pressure-swing adsorption technology was introduced and an overall automatic control scheme incorporating an optimized three-level computer management mode was designed to fit the adsorption device. This scheme includes first-level control equipment, second-level on-site operation monitoring, and third-level information management. Modularization was employed to scientifically dissect the product oil transportation and storage technology. An automatic control process for oil and gas discharge and treat-ment that meets relevant technological requirements was then achieved using S7-300, a programmable logic controller developed by Siemens, ForceControl software developed by Sunway, and other automatic control methods.2. An automation program and circuit control program were designed for carbon bed switching and vacuum bump starting. These programs can control the states of electric valves by calculating the quantity of adsorbed oil and gas so that the operating temperature of activated carbon will be much lower than the fire point of oil and gas.3. The temperature and life of the activated carbon in adsorption tower are critical to the normal operation of oil and gas discharge and treatment de-vice in adsorption process. Real-time temperature monitoring and recording and warning programs were developed to enable feed forward control. These can be achieved by combining automatic control and monitoring, program-ming, and research and development of adsorbents.4. The automation of the whole device was achieved through the design of automatic control of various functions, including temperature and flow monitoring for the cooling loop in the vacuum pump, switching the vacuum pump to the Standby mode, and automatic setup and termination of sup-ply/return oil circulation. Moreover, this device was also ener-gy-efficient.5. In terms of installation and commissioning, a detailed investigation in-to the on-site setting of PID parameters of the automatic control system was made based on previous practical experience. Difficulties and experiences in adjusting PID parameters were summarized, and effective approaches to ad-dressing problems with the device's electromagnetic compatibility during installation were put forward. The author also dug into details of hardware configuration, setting of software parameters, and on-site installation and welding in optical fiber communications.