The filtration and separation area of a station on the China?Russia East Route is set as parallel pipelines,and the uneven distribution of branch flow may occur due to the differences in internal pressure and pipeline layout,which affects the filtration efficiency and the overall work efficiency.In order to avoid pipeline bias, the flow direction of the filtration and separation area is studied based on computational fluid dynamics (CFD).Results show that pressure distribution, turbulent flow distribution, frictional resistance loss along the system,fluid inertia and other factors affect the branch pipe flow distribution.Among 11 parallel pipeline configurations,the axial inlet and radial outlet configuration (Type 3) with inlets and outlets on the same side exhibits the least flow maldistribution overall.Under normal working conditions,flow maldistribution decreases with increasing manifold diameter and branch pipe spacing within the calculation range.Fault conditions,such as branch pipe blockages,significantly exacerbate flow maldistribution in the system.It is concluded that the flow distribution rule and the main factors affecting the flow distribution are obtained,which is helpful to guide the design and construction of gas transmission station.

With the rapid growth of natural gas demand, there is an urgent need to consider the production, supply, storage and marketing structure of natural gas pipeline network, optimize the natural gas sub-customer sales scheme based on system analysis and decision-making theory, and maximize the profitability and economic benefits. With the objective of maximizing the annual total benefit of the natural gas sales pipeline network of the provincial company, taking the gas supply volume from the gas source, the pipeline transmission volume, and the sales volume of the customers as the decision-making variables, and taking into account the node flow balance constraints, the upper and lower limits of the gas volume of the production, supply, storage, and marketing links, the total sales volume of the sub-province constraints, etc., we optimize the gas procurement costs, pipeline costs, storage and transfer costs of storage reservoirs and LNG receiving stations and the customer sales revenues of the gas supply network of the industry chain in the upstream, midstream, and downstream segments. The customer sales revenue adopts the step pricing method, establishes the mathematical model of natural gas customer sales volume optimization, and selects GUROBI solver as the optimization calculation tool to solve the model. The model is tested on the basis of basic data of natural gas pipeline network of a province in the next 10 years to maximize the benefits while meeting the customers' natural gas demand, which verifies the reasonableness and accuracy of the model, and provides advanced analytical tools and technical methods for improving the quality and increasing the efficiency of the natural gas sales business.