Research On Process Safety Of Natural Gas Synthetic Oil Based On Low Temperature Fischer-Tropsch Technology

As the technology of Fischer Tropsch synthesis oil from natural gas in low temperature has gradually applied to industrial production, the demand of studying the process safety is increasing synchronously, especially for the study of physical explosion and fire accident, concretely including the cause of the accident and the scope of the accident, which can lead to greater casualties.Based on the introduction of the domestic technology of iron catalysts for Fischer Tropsch synthesis in slurry bed and low temperature, the article analysis its material and process risk briefly, to make preparations for fault tree analysis (FTA). Then the article use FTA to find out the cause of physical explosion and fire accident and get the following conclusion. The main risk factors of physical explosion in the process of natural gas reformer and Fischer Tropsch reactor are the failure of safety valve in the reactor, blocking vent line in the reactor and failing to detect the reactor in accordance with the provisions. The main risk factors of fire accident in the process of Fischer Tropsch reactor are failing to detect the reactor in accordance with the provisions, the failure of pressure-relied vent device in the reactor and inefficient control of the ignition source.It is possible that pressure vessel, which contains compressed combustible gas in high temperature, relying on its own heat when it happens to physical explosion, can fire. In the conversion furnace process Combustible mixed gas temperature is higher than the ignition temperature of hydrogen. In order to discuss the subsequent accident consequences of physical explosion in the conversion furnace, basing on its shape, the article establishes a cylindrical heat and mass transfer model, using fundamental formulas of heat and mass transfer to calculate the high-temperature combustible gas after physical explosion.There is a possibly ensuing explosion and fire after combustible gas leakage. The article improves empirical formulas of gas leakage rate and calculates leakage rates in the reformer and Fischer Tropsch reactor, then, combining the mass transfer and stress analysis to build a new model to calculate non-steady trajectory, which can fill the research gap on non-steady trajectory effectively. What is more, the article selects the thermal radiation damage models of jet fire, fireball flame and shock wave damage model of vapor cloud explosion respectively, to calculate subsequent influence scope of the leakage accident in the reformer and Fischer Tropsch reactor and sphere of fireball influence in the reformer after physical explosion.