Study On Flow Simulation And Pipeline Thermal Insulation For Long Distance Steam Transportation

The use of waste heat from the power plant for district heating has a double benefit,which can not only improve the comprehensive utilization efficiency of the power plant’s energy,but also play an energy-saving and environmental protection role on the demand side.Therefore,it is more and more widely used in practical projects.With the continuous expansion of the heating radius,the safety and economic operation of longdistance transportation pipelines have attracted more and more attention.This paper presents a calculation model for long-distance steam transportation,and conducts simulation research and experimental verification on the steam flow and thermal resistance.The research results can provide theoretical guidance for the optimal design and operation of the pipeline.In this paper,a coupled calculation model for steam flow is established.At the same time,a method for calculating the thermal resistance of thermal conductivity with temperature is proposed for the multi-layer insulation structure of the steam pipeline,and the relationship between the main steam parameters and the thermal insulation resistance in the flow direction is analyzed.In addition,in the steam flow model,the phase change during long-distance transportation is considered to increase the analysis of steam condensate.At the same time,the relationship between the location of steam condensation and the amount of condensate and the flow rate,thermal insulation resistance and steam superheat is studied.The results show that,compared with the traditional model that uses the average temperature as the thermal conductivity of the thermal insulation material,the thermal insulation resistance of the pipeline calculated by the model in this paper is higher.At the same time,due to the addition of the condensate part in the calculation model,the main parameters of the steam calculated by the simulation have changed greatly compared with the previous model,especially the steam temperature has been significantly increased.In addition,this paper uses the method of life cycle cost to analyze the economic impact of the pipeline insulation material arrangement and steam flow rate on the pipeline system,and optimizes the design of the long-distance pipeline.Finally,the data of the long steam pipelines under different operating conditions were collected,the thermal insulation resistance values of different steam pipelines were measured,and the data of the location and amount of steam condensation in the pipeline are collected.In addition,the main parameters of steam in each case were collected.The simulation results(flow rate,temperature,pressure,density and flow rate)are compared with the measured values.The results show that the thermal insulation resistance value,the position of the steam condensation point and the amount of condensation are in good agreement with the simulation results.At the same time,the calculation accuracy of the main steam outlet parameters is significantly improved,and the temperature and pressure errors do not exceed 5K and 4%,respectively.