Improvement Of Comprehensive Utilization Efficiency Of Cold Energy In LNG Reception Station

When we import large quantities of LNG, we also import high-quality cold energy it carries. If liquefied natural gas directly evaporates then absorbing heat in the environment, rising temperature, it will waste cold energy that LNG carries in vain, and bring the environmental pollution caused by the cold. Because of the objective reasons that the start of LNG cold energy utilization is late, there are still not too much mature and advanced technology in this area. Even there are a few unit technology of cold energy utilization for the practical production, they also accompany with the phenomenon of low cold energy utilization efficiency and the large exergy loss resulting of most of the cold energy being no reasonable application.Exergy analysis method has a widely recognition and use. Combining exergy analysis method with the LNG cascade utilization process to improve the LNG cold energy utilization efficiency can improve the efficiency of LNG cold energy utilization effectively and reduce the energy loss in the cold energy utilization. Based on the analysis of the operation and application status cold of energy utilization technology about LNG receiving station at home and abroad, the cold energy utilization efficiency of LNG receiving station is studied in this paper. The study includes:(1) Based on the study of the situation about the cold energy utilization of LNG receiving station, the main existing problems in the current utilization are were pointed out.(2) After the analysis of the main factors that influence the impact attenuation of LNG cold energy, the rule of LNG cold energy along with the change of these factors is explored.(3) On the basis of the analysis of each unit of cold energy utilization process, the applicability of LNG each unit using process is comprehensively evaluated and the analysis results of practical significance are obtained in terms of cost, market demand, construction area.(4) Based on the requirements of LNG cold energy actual use of unit using technology, preliminary cascade scheme is established.(5) After studying the different exergy analysis method, we can choose the thermodynamics analysis as the suitable LNG cold energy efficiency analysis method according to their characteristics and the actual application situation are discussed according to the real gas state equation (RKS equation) in this paper.(6) By using the thermodynamic analysis, the exergy efficiency of preliminary cascade utilization scheme has carried on the detailed numerical calculation, and then the cascade utilization of the highest exergy efficiency is determined.(7) Combining with the actual working condition of a LNG receiving station in Zhuhai, we put forward cold energy cascade utilization about the LNG receiving station in Zhuhai and furtherly design the appropriate cascade cold energy utilization scheme for the LNG receiving station. Research results show that compared to using a single process program alone, the mode of LNG cold energy cascade utilization greatly improves the efficiency of cold energy utilization. So cascade cold energy utilization is the important direction of the LNG cold energy utilization in the future.