Research On Emergency Response Technique Of Fire Accident In High Sulfide Natural Gas Station

Currently, the high sulfide natural gas fields are broadly exploited both domestically and abroad. However, H2S in natural gas with high concertration cause strong corrosion to the drilling equipments and gathering pipelines. Besides, the flamability and exposibility of the natural gas can easily lead to accidents of jet fire, which can cause serious damage. Gas station is an important part of the natutal gas gathering system in where plenty of equipments and pipelines are exsited. It's significant to study the occurring and developping rules of the conflagration, evaluate the accident risk and propose the emergency response techniques purposely for high sulfide natural gas station. This dissertation also combined with the sub-topics"Gathering process and safety control techniques in high sulfide gas field"of national science and technology special project"Exploitation in Large-scale oil & gas fields and coal bed gas"(No. 2008ZX05017).After specific indentification for the natural gas property, gathering process and equipments of CHUANDONG natural gas filed, the main risks of the gas station are jet fires of the horizontal gas-liquid separator and production pipelines. Based on Large Eddy Simulation, taking specific characteristics of parameters into consideration such as media components and phase state in separator and production pipelines, jet fire models of a horizontal gas-liquid separator and production pipeline were established by Fire Dynamics Simulator (FDS). A mixture fraction model is used to account for the evolution of the fuel gas from its surface of origin through the combustion process. The numerical simulations of jet fire with 0.1016m orifice diameter was conducted, then flame geometric dimensions, flame temperature properties and behavior of thermal radiation were analyzed. Calculation results show that jet fires of separator and production pipeline have great risk to the glycol pump, the support of production pipelines and methanol set. Meanwhile, according to the simulation results, the fire detection system was optimized that the equipments zone in natural gas station was divided to be 5 detection zones and the temperature detectors were properly arranged. Considering the intervene effect of fire automatic control system, under the protection of sprinkling system of production pipelines and water curtain system of equipment sets, the highest temperature of flame decreased by 500℃and the safety coefficient of methanol set was improved. The emergency resourse storage scheme was set up mainly foucusing on the designation of fire automatic control system and collocation of portable fire extinguishers. Fire-extinguished techniques of high sulfide natural gas in natual gas station were proposed. Rely on the numeric simulation results, the safety distance between the firemen and the afire equipments was identified. According to ESD designing rules, the emergency shut down system level in natural gas station was identified and coresponding measures for accident prevention were summarized.