Applying Computational Fluid Dynamics to Reduce Greenhouse Gases Emissions in Natural Gas Compressor Stations

Abstract Concerns about greenhouse gas emissions are rapidly increasing and becoming a priority in operations involving hydrocarbons. In natural gas transportation systems, compressor stations are commonly found to be the primary sources of emission of these gases. Some compressor stations with emergency depressurization systems are designed with a continuous purge of natural gas into the environment to prevent air ingress into the depressurization system, therefore avoiding formation of an explosive atmosphere within the line. Many of these projects were conceived before the widespread discussion on environmental issues, resulting in less concern about the amount of purged natural gas. To align these stations with emission reduction goals, the industry is seeking for solutions. However, most existing methods require more complex changes to safety characteristics and risk analyses of the plant. This work proposes a rapid and cost-effective method to determine the minimum flow rate of natural gas capable of preventing the formation of an explosive atmosphere in the depressurization piping. The approach involves simulations in Computational Fluid Dynamics, varying boundary conditions. When applied to a compressor station as a test case, the method indicated a flow rate reduction of nearly 50%.