Research And Design Of Experimental System For CO₂ Leakage And Diffusion Law

High-pressure CO₂ gas transportation currently has two transportation methods:ship and pipeline.If long-distance transportation is required,the efficiency of pipeline transportation will be greatly improved.However,pipeline transportation has greater hidden dangers.If CO₂ gas leaks in a closed and densely populated environment,There will be a great possibility of causing serious damage to the organisms in the high-concentration CO₂ area.In the related fields of studying gas leakage,there is a large gap in the degree of development at home and abroad,and foreign countries are far ahead of China.Although the diffusion model has formed a relatively mature theoretical system,gases with different characteristics adapt to different diffusion models.For CO₂ gas research,it is necessary to establish a corresponding experimental system and diffusion model for in-depth research.Based on the above background,this thesis has mainly done the following tasks and got the following conclusions:(1)By investigating the current research status of high-pressure CO₂ leakage experiments at home and abroad,combining single-chip control technology and Kingview monitoring interface,a complete small-scale CO₂ leakage experiment system was designed to realize the automatic monitoring function of CO₂ leakage experiments.A series of technical problems encountered during the experiment were solved,and the experimental results showed that the system can accurately simulate the CO₂ leakage process and the leakage phenomenon.(2)By changing the experimental conditions,several small-scale comparative experiments of CO₂ leakage were carried out,and the concentration data of different leakage apertures,hole shapes,leakage pressures,and leakage pipe diameters were compared in groups.Combining with the relevant theories of heavy gas diffusion,this paper analyzes the concentration change law and overall distribution characteristics of high-pressure CO₂ in a limited space after leaking from the pipeline:when the weather conditions such as temperature,wind direction and wind speed are stable,the concentration of CO₂ after the leak will be caused by gravity The phenomenon of concentration stratification occurs due to sedimentation,and with the increase of time,the stratification phenomenon will become more and more obvious;the CO₂ concentration distribution is positively related to the leakage pressure and the leakage diameter,and has no direct relationship with the leakage hole shape and the leakage pipe diameter;The timetable for the arrival of hazardous concentrations under different working conditions is drawn to provide a reference for the time of arrival of hazardous concentrations for possible CO₂ leakage accidents.(3)By selecting a set of experimental conditions(the leaking pipe diameter is DN25;the leaking pressure is 0.2Mpa;the leaking hole diameter is 1mm;)the diffusion process is simulated in the FLUENT fluid mechanics software,and the simulated concentration cloud diagram at different times is drawn.According to the simulation cloud chart,the experimental simulation process is validated;the concentration cloud chart with or without vents under this working condition is compared,and the concentration distribution at different times under different ventilation modes is compared according to the cloud chart;the CO₂ hazard in the limited space at different times is drawn The three-dimensional distribution map of the area provides data prediction and visual graphic reference for possible CO₂ leakage accidents.