Research And Optimization Of Cold Energy Of LNG Receiving Terminal For Power Generation And Ice Making Process

With the acceleration of transformation of energy structure,the import of LNG in China is increasing year by year.More and more LNG receiving terminals are gradually developing LNG cold energy utilization projects.As far as it is concerned,there is still a gap of the cold energy utilization project of LNG receiving terminal compared with Japan and South Korea.And the LNG cold energy single use technology has become mature or has many successful precedents,but the utilization ratio is not high.In order to improve the utilization rate,it is necessary to use the LNG cold energy to make the cascade utilization.Therefore,to improve the utilization of cold energy at the same time,set a model for domestic related projects,in this paper,a set of simple and wild ranging LNG receiving terminal cold energy is used for power generation and ice making technology.In this paper,the development status of cold energy utilization of LNG receiving terminals at home and abroad is investigated through literature investigation and practical project research.According to the status of LNG receiving terminal,a set of cold energy of LNG receiving terminal is designed for power generation and ice making technology,and the combination of series and parallel is used,and high grade cold energy is used to generate electricity,and low grade cold energy is used to make ice..Using the molar ratio of 1:1 C2C3 as fiirst refrigerant,the mass fraction of ethylene glycol solution of 30% as the second refrigerant,determine the key parameters,use Aspen Plus simulation software using exergy analysis method and cold energy value evaluation method.The results show that when setting of superheated temperature is 70℃,expander outlet pressure is 0.11 MPa,the system of exergy efficiency reaches 19.93%,the whole process of cold energy value is 71.47yuan/(h·t).According to the optimization direction proposed in the second chapter,there is a multivariable synergy phenomenon in the LNG cold energy utilization process,and we use genetic algorithm,VBA,Excel and simulation software Aspen Plus to integrate optimization,and set up a visual simple Excel interface.Through the establishment of constraint conditions,determine three variables and the range of energy efficiency,to further establish the power output and economic benefit as the objective function of the variables,the optimization results show that the power generation part of the highest exergy efficiency is up to 29.64%,the system of exergy efficiency is 30.12%,the highest power generation capacity of 38.32kW/t,the highest economic benefit was 98.46 yuan/(h·t).Finally,the system scheme is designed.The amount of LNG designed for cold energy projects is 35t/h,and equipment selection,operation flexibility analysis and investment profit analysis are carried out.In the normal exergy efficiency as the goal,results show that the power generation unit of exergy efficiency is 29.64%,the system energy efficiency of 30.12%,power generation capacity of 1338.7kW,ice amount was 55.64t/h.The initial investment of the technology is 53,900,000 yuan,the economic benefit is 24,696,400yuan/year,and the investment recovery period is 2.18 years,showing great economic efficiency and feasibility...