Research On Venting Design Of Natural Gas Compressor Room

Natural gas compressor is the commonly used equipment in natural gas transmission and distribution system. The compressor is in compression compartment. The failure frequency is so high that it is easy to cause fire and explosion accident. The fire and explosion accident will bring great threat to the surrounding environment and the safety of people's lives and property. Therefore, it is of great practical significance and scientific value to carry out the research on the venting of natural gas compressor compartment.This paper established the gas compression compartment explosion venting numerical model and analysied the venting features and the influence law.For gas compression compartment explosion venting design problems, this research refered to the relevant technical standards and proposed the optimization design method of gas compression compartment venting. This paper carried out the research work in the following aspects:(1) The hazards of gas compression compartment explosion are analysed with Preliminary hazard Analysis(PHA)method. Results show that gas compression compartment combustion explosion accident happened mainly by the design, manufacture, installation and maintenance of reasonable cause gas leaks, spontaneous combustion of coke at high temperature and pressure, liquid shock, misuse and illegal operations, etc. The fire and explosion is a catastrophic accident, and the effective prevention and mitigation measures should be adopted to prevent the accidents and alleviate the damage of traffic accidents.(2) The numerical model of explosion vinting inl natural gas compression compartment is established with the FLACS software. The grid sensitivity is analyzed, and the optimal number of grid is determined. The validity of the model was verified by the published literature data. The numerical results show good agreement with the literature data. The maximum error is -5.2%, which belongs to the engineering acceptable range and verifies the applicability and accuracy of the explosion pressure relief model established in this paper.(3) Based on the established the numerical model of explosion vinting in natural gas compression compartment, The effects of ignition position on peak overpressure are studied and the ignition source of the overpressure peak maximum is chosen as in the subsequent calculation of the initial ignition conditions. Set different accident scenarios and simulate gas explosion pressure and flame propagation behavior under chemical equivalence ratio methane air. Basic characteristics of the natural gas compressor compartment explosion venting are analysed. The results show that the explosion pressure, pressure rise rate and flame temperature are not uniform in the compression compartment. In the same horizontal plane, the explosion peak pressure, the maximum rate of pressure rise and the maximum flame temperature show show high middle position and the two sides are low.The explosion peak pressure, the maximum rate of pressure rise and the maximum flame temperature increase with the increase of height in the vertical direction. The inner side of the wall near the pressure relief port is affected by the negative pressure.(4)The aimof the present research was to performCFD simulations in order to study the influence of various factors on explosion venting in compression compartment, including the characteristics of the the vent area ratio, length to diameter ratio,activation pressure and weight of relief panels.The results show that the peak pressure, the max rate of pressure rise and the maximum flame temperature increase with the decrease of vint area ratio. When the pressure relief ratio is greater than 0.5, the variation of the explosion parameters is small. The relationship between the peak pressure and the activation pressure is linear increasing.The max rate of pressure rise and the maximum flame temperature increases with pressure relief plate activation pressure increases. When the activation pressure is greater than the 0.2barg, they increase faster. The peak pressure, the negative pressure peak value, the maximum rate of pressure and the maximum flame temperature increase with the increase of the ratio of the length to diameter ratio of the compression compartment. When the ratio of length to diameter is greater than 3, the increase is faster. When the mass of pressure relief pressure plate is changed in the range of 5kg.m-2?60kg.m-2, it has little influence on the peak pressure, negative pressure peak value, maximum rate of pressure rising and maximum temperature of flame.(5) A simulation scheme is developed by using the orthogonal test method. The explosion overpressure peak value of each scheme is calculated. The effect of vint area ratio, activation pressure, ratio of length to diameter and the quality of relief panels on the peak of explosion overpressure were analyzed by using the improved grey correlation degree method. The result shows that the impact of various factors influencing the degree of peak overpressure is as follows:the activation pressure of relief panels, the vint area ratio, the length to diameter ratio, the quality of relief panels.(6) Simulation results compared with the relevant standards, the results show that NFPA68-2013,EN14994-2007 and GB50016-2014 can ensure the effective vinting.But NFPA68-2013 and GB50016-2014 are too conservative.This paper puts forward the suggestion on the revision of the explosion vinting design in GB50016-2014:the value of the vint ratio should be classified in detail. The minimum C of methane gas is desirable 0.05. The activation pressure of relief panel should be considered.The activation pressure should not be greater than 0.2barg.The length to diameter ratio of gas compression compartment must be less than 3.The mass of relief panel don't exceed 50kg·m-2.(7) The vent area of natural compression compartment may not be up to the GB50016-2014 requirements. The plant may produce resonance due to the vibration of the compressor.In view of the two problems, based on CFD technology and modal analysis method, the optimization design method of gas compression compartment venting is proposed. The method is applied to the compression compartment of a storage and distribution station. The feasibility of the method is verified.