Lng Bog Process Control Systems Design And Implementation

Liquid nature gas (LNG) is applied extensively as a kind of high quality clean energy. The first Shanghai LNG terminal is located in Shengsi County, Zhejiang Province. When the LNG project achieves its target, it may produce 4×109m3 natural gas, which plays an important role in Shanghai energy structure. LNG works at-160℃, which may easily generate heat exchange when it is stored in the terminal. Finally boiled off gas (BOG) produced. So the BOG control system is the most complex and important system.BOG traditional control is completed by local workers that neither is advantaged to safety, nor accords with the development tendency of the modern corporation, but costs much manpower. With the development of industrial automation systems, the technology based on the computer is applied in this design. According to the task and requirements of the LNG.automation control, the BOG compressor and the BOG recondenser are controlled by distributed control system (DCS). And YOKOGAWA Centum CS3000 sets up the DCS system, and System Viewer software and Control Drawing software achieve the configuration. The system can monitor the real system operation of the BOG compressor and BOG recondenser, look over the real time trend, and play the protective role for equipment, ensure that production safety is reliable.The system was finished in November 2009. It has been tested for three months, and basically achieved the expected target. This system greatly improved automation level of natural gas purification, reduce the number of the operators, and the cost of the enterprise declined. The system has been run normally for five month by the paper was finished, which ensures the safety production. So it has great application value. The LNG BOG process control system in this design is an integrated and open system. In this system, type choosing and configuration is reasonable, monitoring interface is friendly. It completely satisfies the requirement of production control, and it is steady to run in scene. This system is the part of the LNG DCS control system. According to the project requirements, this paper focuses on the core equipment controlling such as BOG compressor and BOG recondenser,.