Optimization On Allocation Of Compressor Units For A Gas Pipeline

Compressor station is an important part of gas pipelines.In most gas pipeline designs,the backup plan of compressor is usully limited to the standby unit mode,which is often determined by experience and has no quantitative analysis.This paper puts forward three optimization methods on allocation of compressor units for a gas pipeline seperately based on the unit standby mode,standby power mode and the combination of the two modes.The optimization method based on the unit standby mode includes failure probability calculation and fault simulation to determine several serious fault conditions,and then through simulation and quantitative analysis on pressure and rate of flow to determine the compressor configuration scheme.The optimization method based on power reserve assumes the compressor failures from back to front along the pipeline and determines the standby power through steady-state calculation,and then determine the compressor configuration scheme.Based on the above two methods,the compressor configuration optimization method,which combines the standby of the unit with the standby of the power,is further proposed.Firstly,the standby power required by each station is calculated according to the optimal method based on the power standby mode,and the preliminary configuration of the compressor is carried out.Then,the compressor station that needs to be set up according to the optimal method based on the standby mode of the unit is determined to cope with the condition that there are multiple units failure at the same time on the whole line.The above mentioned three methods are respectively applied to the A-B line of central Asia gas transmission pipeline and three configuration schemes are obtained.The scheme based on the unit standby mode reduces three standby units from the original eight,which ensures the reliability of gas transmission and reduces the investment cost at the same time.The power reserve method has only one standby unit across the whole line,with an average power reserve rate of 23.2%.The investment cost of the compressor is the lowest,but it may not be able to cope with the failure conditions of multiple units at the same time.By using the method of combination of standby units and power standby,four standby units are reduced,and the average power reserve rate is 19%,achieving a balance between reliability and economy.