Analysis Of Leakage And Diffusion Of Overhead Low Pressure Gas Pipelines

In the mid-term of the 12 th Five-Year Plan,the State Council promulgated ten measures for preventing and controlling atmospheric pollution,including reducing the discharge of pollutants.Ten series of prevention and control measures have been taken,such as comprehensive renovation of small coal-fired boilers,renovation of urban dust,speeding up the adjustment of existing energy structure and increasing the supply of clean energy such as natural gas.In 2017,the largest new rural "coal to gas" project in the history of Beijing was announced.Among them,overhead low pressure natural gas pipeline is the main end gas transmission form.These pipelines,which are laid on the walls of civil buildings by means of threaded links or supported by supports,have become ubiquitous safety hazards while undertaking a large number of gas transmission tasks.Once the leakage accident occurs,the consequences can not be imagined,so it is necessary to strengthen the safe operation and disposal,to achieve fine management.Therefore,it is necessary to control the law of leakage and diffusion of overhead low-pressure natural gas pipelines in advance,and evaluate the hazards of subsequent accidents,so as to be prepared and prevented.This paper summarizes in detail the research results on leakage and diffusion of natural gas and accident hazards by scholars and research institutes at home and abroad.On the basis of this,a digital model is established to simulate the leakage and diffusion of overhead low-pressure natural gas pipelines.Different external environment wind speed,leakage and diffusion duration,building intervention distance and other factors were selected as variables to simulate and compare one by one.Then,the hazards of explosion accidents after diffusion of overhead low-pressure natural gas pipelines under specific conditions are assessed by using the vapor cloud explosion model,and the results are presented in the form of hazard radius.Finally,the preventive distance of the surrounding areas of overhead low-pressure natural gas pipelines is proposed.In this paper,theoretical analysis and CFD simulation will be used to simulate the leakage and diffusion of overhead low-pressure natural gas pipelines.At the same time,the explosion accident model will be used to evaluate and divide the hazard areas.The conclusions obtained have certain reference value for the hazard assessment of natural gas leakage accidents and the layout of overhead low-pressure natural gas pipelines and facilities.