The Loop And Simulation Experiment Of The Safety Shut-off Of The Gas Pipeline Cut-off Valve

As the pipeline security equipment, the block valve can shutdown during the gas pipeline leak. Pneumatic cut-off valve with the executing mechanism is key to the self -closing valves.It worked by detecting the pressure drop rate of the pipeline, then taking some actions, when the gasline is leaking and broken.Scientific and reasonable value set of pressure drop rate has an important influence on the normal work of the cut-off valve, too small or too large pressure drop rate sets are not conducive to the safety of the pipeline. If the set pressure drop rate is larger, once in the middle of adjacent valve chamber of break pipe accidents, the line block valve can not feel pressure drop rate and make the correct actions, then exacerbating the economic losses and the imPact on the environment. If the pressure drop rate is too small, when the pipeline pressure fluctuation, it’s easy to cause the error turn-off, cause outage upstream of the compressor, and serious influence on gas supply’s safe and stable.According to the statistics from 2007 to 2011, the west- east -gas line stations occurred about 90 pneumatic valve shutdown situations.The normally off is about 70 times, wrong turn off is about 20 times. From 2006 to 2007, the Zhongwu gasline have about 16 times wrong turn off.In this Paper,the research focus on the natural gas pipeline cut-off valve malfunction and can not be timely response and effect factors of the, cut-off valve shutdown the proper value of pressure drop rate and the basis of reasonable selection. Based on the software platform of high pressure gas pipeline leak detection experiment device and simulation,the main content of the work completed are as follows:(1) Analysis of the influencing factors on pressure drop rate and the pressure gradient completed gas pipeline leak location, leak aperture, pipeline pressure level and other factors in the leak detection experiment device of 10mm and 42mm two pipe diameters are respectively;(2) Using the simulation method, the leakage condition and transportation conditions was studied, and analysis of the changes of leakage condition and distribution under different conditions of pressure drop rate with time, the two clamping force, get cut off valve ideal shutdown threshold;(3) Through the simulation software, analysis the factors’sensitivity of pressure drop rate and the pressure gradient;(4) On the threshold value algorithm fitting, the fitting formula under different influence factors; the pressure drop gradient threshold value was simulated, obtained the corresponding fitting formula, the auxiliary application and transmission cut-off valve safety gas pipeline shutdown Parameters.