Research On The Joint Operation Optimization Of The Air Cooler And Compressor Of The Pipeline System In The West Section Of The Second West Line

In the long-distance natural gas pipeline,the energy-consuming equipment of the compressor station mainly includes air coolers and compressors.When the natural gas temperature of the compressor outlet is high,the volume flow is large and the viscosity increases,which will lead to the increase of friction loss of the pipeline.Reduce the natural gas temperature at the compressor outlet by opening the air cooler,thereby reducing the volume flow and viscosity,reducing the friction loss,reducing the pressure required by the compressor,and then reducing the energy consumption of the compressor unit.Simultaneously opening the air cooler,the unit will generate a certain amount of power consumption.If the energy consumption of the compressor is greater than the energy consumption of the air cooler,more economic benefits will be obtained.Therefore,it is necessary to establish a combined operation optimization model for the long-distance pipeline air cooler and compressor.In order to achieve this goal,this paper investigates the numerical simulation of air cooler,energy consumption calculation model of air cooler,calculation model of compressor energy consumption and optimization of gas pipeline operation in recent years.Based on literature research,the main research contents and achievements of this paper are as follows:(1)Based on the air cooler model parameters of the west section of the second line of the West-East Gas Pipeline,establish a three-dimensional simplified model of the air cooler,use the ICEM software to divide the structured grid,and calculate the natural gas temperature of the air cooler by Fluent flow field analysis software.Analyze the influence of several variables,and fit the calculation formula between the air cooler's temperature drop value of natural gas and the number of air cooler start-up,ambient temperature and compressor outlet natural gas temperature,and verify the fitting formula with field operation data.The calculation formula can obtain the outbound temperature of the compressor station,reduce the calculation amount of the optimized operation,and avoid the complicated heat transfer calculation of the air cooler,which has certain innovation.(2)According to the air cooler energy consumption,compressor energy consumption and the coupling relationship between the pipeline system,the air cooler and compressor combined operation optimization model is established,and the minimum energy consumption of the air cooler and compressor is the objective function.The variables are the outbound pressure,the number of air coolers,and the number of compressors.The constraints include pipeline strength constraints,flow balance constraints,air cooler performance constraints,compressor performance constraints,etc.The optimization algorithm uses genetic algorithm,particle swarm optimization and simulated annealing.The algorithm is solved by three algorithms.(3)Taking the western section of the second line of the West-East Gas Pipeline as an example,firstly study the basic parameters of the stations along the line,use the established optimization model,and then use the genetic algorithm,particle swarm optimization algorithm and simulated annealing algorithm to solve the corresponding optimization scheme based on Matlab programming.All the three optimization algorithms can effectively solve the model.In terms of solution time,the simulated annealing algorithm has the lowest solution time,106.64 seconds,and the highest optimization efficiency when solving the optimization scheme in winter.When solving the optimization scheme in summer,particle swarm optimization algorithm has the lowest solution time,138.95 seconds,and the highest optimization efficiency.Through comparison of energy consumption calculation,it is found that the optimal running scheme of air cooler starting up in winter solved by simulated annealing algorithm has the lowest energy consumption,but the solution time is the longest,reducing the total production energy consumption by 43188.43tce,33.77%of the total production energy consumption,and production unit consumption decreased by 73.69kgce/(107Nm3·km).The optimization scheme of starting up and running of air cooler solved by genetic algorithm in summer has the lowest energy consumption,and the solution time is between the other two algorithms.It reduces the total energy consumption of production by 35155.89tce,28.63%of the total energy consumption of production,and production unit consumption decreased by 66.71 kgce/(107Nm3·km).Therefore,simulated annealing algorithm and genetic algorithm can be used respectively in winter and summer to solve the operation optimization scheme of the western section of the Second West-East Gas Pipeline,which can significantly reduce the energy consumption of stations along the western section of the second line,thus proving the correctness and practicability of the optimization model.(4)This paper also innovatively takes the environmental temperature of stations along the line as the optimization variable to optimize.It is proposed that the ambient temperature of air coolers should be recommended for each air compressor station along the western second-line in winter and summer.When the air cooler is opened above this temperature,it will increase the energy consumption across the board,which is not economic.When the air cooler is opened below this temperature,the energy consumption of the whole long-distance pipeline will be reduced,and greater economic benefits will be gained,which has certain guiding significance for the actual production and operation of the compressor station.