Safety Study Of Flash Tank Based On MDEA Natural Gas Desulfurization

Sour gas purification process is accompanied with high temperature, high pressure, corrosion cracking, low temperature brittle and other dangerous working conditions, safety researches on the process are necessary. This thesis took natural gas desulfurization flash tank as the research object, based on hydrogen sulfide and carbon dioxide corrosion mechanism and solubility models of H2S-CO2-MDEA-H2O system, established a flash tank failure potential method for calculating the radius of influence. The main contents are as follows:(1)Based on the principle of acidic gas absorption in MDEA solution, established a simplified model for the solubility of H2S-CO2-MDEA-H2O system using activity-fugacity coefficient method.(2) Using Aspen Hysys modeled the process of natural gas purification process, analyzed the influences on the H2S content in flash vapor caused by the changes in H2S content in the feed gas, temperature, absorption pressure, flash pressure, ratio of the solution and sour gas load.(3) Possible consequences of flash gas leakage as H2S poisoning, jet fire, fireball and vapor cloud explosion were calculated respectively, in which H2S poisoning has the largest potential impact radius, therefore, the potential impact radius of flash gas leakage should be determined by the H2S poisoning consequences.(4) Through the analysis of MDEA rich fluid leakage process, established the dynamic MDEA rich solution leakage and H2S releasing model on the basis of solubility model. The results showed that:when the pore diameter is 100mm, the scope of the H2S diffusion is 63～181m; when the pore diameter is 200mm, the scope of the H2S diffusion is 96～333m; when the pore diameter is 300mm, the scope of the H2S diffusion is 168～412m; when the pore diameter is 400mm, the scope of the H2S diffusion is 238～434m;...