Loss Assessment And Process Optimization Of Natural Gas Production In LNG Receiving Station

In LNG(liquefied natural gas)receiving station,due to high evaporation characteristics of LNG,it is inevitable to produce BOG(boiled off gas).Treatment and recycling of BOG in the LNG receiving station not only can improve the economic benefit,but also can greatly reduce the emission of natural gas and the pollution to environment.Currently,a large number of BOG will come from the process of daily discharging,loading and storage in LNG receiving station.After compression and reliquification,large amount of BOG flow into the carburetor with majority part of LNG;a small amount of BOG,after compression,directly into the distribution system.But still a small amount of BOG will be emitted into the atmosphere,causing environmental pollution.Therefore,for the operation of the LNG receiving station,it is necessary to carry on the comprehensive research of energy saving and emission reduction,optimize the operation process.These methods can promote the energy-saving operation of equipment and effectively reduce the emission of BOG and other polluting gases.Which achieves the low energy consumption,low emissions and high efficiency of the receiving station.The main work and results of this paper are as follows:(1)Through the analysis of the stock of the tank,stock of the gas pipeline,errors of the sale of the liquid gas and natural gas sales,quantity of the normal production and the quantity of the receiving,we can grasp the proportion of the production error.(2)The metering errors of the LNG receiving station is optimized,through the transfer process,transfer unit of LNG and the meterage method of natural gas;analysis of natural gas loss in the station and the method of reducing meterage error.(3)By analyzing the error of meterage system and the factors of BOG,combining with BOG recovery process to optimize the recovery of BOG;Research to reduce the leakage of all aspects of the BOG and the use method of lamp.Based on the bog quantitative analysis and control measures to determine the reasonable loss index of BOG in each link of receiving station and comprehensive research on BOG loss control method of LNG receiving station.(4)This paper proposes the control measure of restricting meterage error further.In the actual operation process,it monitors the rate of evaporation of LNG export,unloading from boats,the pump operation and the heat leakage of storage tank.A good measure of cold preservation and improving the using efficiency of pump can reduce BOG producing.