The Layout And Distribution Research Of Monitoring Points For Hazard Gas In Gasification Unit

Based on the early stage investigation and preliminary analysis,the potential hazards in the process of gasification have been identified.The selected hazardous sources in the gasification unit include gasifier,raw gas knock-out drum and 1st Flash tank.For the reasons,such as large diameters of pipes,difficulty of tightening the flange,high pressure of outlet gas,high velocity of raw gas,and many corrosive elements in the raw gas,there would be a big possibility of leakage of the raw gas caused by the outlet flange.Thus the flange leakage would be aimed as the research object of this paper.The paper employs ANSYS software as simulation tool to simulate 18 working cases under three wind directions and two different leak diameters respectively.According to the simulation results,we made a study of the spreading area and found out the proper layout for the monitoring points.The study indicates that once the outlet flange of gasifier leaks,leaking gas would firstly arrive at the buffer tank;The leakage of the knock-out drum's outlet flange would firstly reach the bottom of gasfier,jetting washing drum,collection drum for tailing and discharge liquid,washing tank.The leakage of 1st Flash would firstly reach the flash cooler.Because of the high outlet pressure of the gasifier and the knock-out drum,the potential result is serious and it would influence a large area,as a result,the density of the monitoring points should be large in this area.Once there is leakage of flammable gas,the gas is spreading in the shape of cumulus clouds and in the direction of downstream wind.The time that gas reaches the edge of workshop frame is under 20s.The features include,a)gas that from bigger leakage diameters consumes less time than that from smaller leakage diameters,b)the spreading scale of smaller leakage diameters is larger than that of bigger leakage diameters.The layout density of monitoring points should be larger in the downstream wind and in order to lift the accuracy and shorten the response time,monitoring devices should be installed on the equipments that gas might spread to.Monitoring points should have function of audible and visual alarm,which can warn the workers on the field and let them take effective measures to avoid the damage of the expansion of the accident to the company's property and personal safety hazards.