Calculation Of Wax Cleaning Period Of Waxy Crude Oil Pipeline

At present,the crude oil produced in our country is mainly waxy crude oil,which is easily waxed when pipeline is transported,and the cleaning pipe is needed after running for some time.This paper mainly studies how to determine the economic cleaning period,reduce the operating cost of the pipeline,and provide the theoretical basis for future engineering applications.Based on the analysis of wax deposition mechanism and influencing factors,the weight of wax deposition rate was determined by principal component analysis.Taking into account the effect of the true distribution of oil temperature along the pipeline on the thermal and hydrodynamic properties of crude oil and the change of flow type,the calculation method of heat and hydraulic power in the course of the operation of the hot oil pipeline is given.On the basis of the forecast,the paper first establishes the optimization model of pipe cleaning cycle based on the oil cost as the objective function and the pipe running days as the independent variable,and writes the calculation program.By means of the actual data in the field,it calculates and analyses the law of variation of the unit oil transport cost with the number of days of pipe running and the unit economic oil transport cost with the different oil temperature of the station,and determines the optimal pipe cleaning period.On the basis of the forecast,the paper first establishes the target function of the oil transport cost,the model of the cleaning cycle optimization of the oil pipe with the number of days of operation of the pipe as the independent variable,and the calculation program of the wax cycle optimization with the number of days of operation of the pipe and the variation of the remaining wax cycle with the same temperature of the oil cycle optimization of the oil cycle,the quantity of transport and the ground temperature along the pipeline with the actual data of the field.Based on the actual pipeline calculation on site,the variation law of pipe cycle and oil cost with residual wax thickness and optimal residual wax thickness with different oil temperature,transport quantity and ground temperature along the pipeline is analyzed.Finally,the economic practicability of the two models for the periodic calculation of pipe cleaning under different working conditions is analyzed.The calculation results show that the optimization model is comprehensive,reliable and accurate.The influence of the residual wax thickness on the cost of economic transportation is related to the operating condition of the pipeline.