Optimization of operating condition for offshore power plant combined with LNG regasification

Abstract

This paper proposes a power generation system combined with LNG regasification to utilize LNG cold energy for combustion air cooling and steam condensation. The process design and simulation are conducted for both the conventional system without the air cooling and the proposed system. A case study is performed using the environmental conditions of Busan, a southern port in the Korean peninsula. The operating conditions of the system are optimized for the given design specifications and environmental conditions to maximize the net output power using nonlinear programming (NLP). In general, the air cooling is more effective than the steam condensation in utilizing the cold energy recovered from LNG. The optimum splitting ratio of the cold energy utilization for the air cooling to the steam condensation, however, mainly depends upon the air temperature. That is, the cold energy should be directed to the steam condensation for a low air temperature, and to the air cooling for a high air temperature. The efficiency of the optimized system shows an increase of 0.1% to 12% in the net power output over that of the conventional system, depending on the air temperature.