Application of PHAST software in methane emission factor for startup process of gas compressors (Case study: Iran gas transmission operation district 2)

Introduction: Today, due to the discussion of carbon management as well as the reduction of greenhouse gases and national and international commit-ments involved in this regard such as the Six Development Plan (2016-2020) and climate change convention it, is necessary to calculate and manage all industrial processes that lead to the greenhouse gases emission. Methane is the main ingredient of natural gas, which its potential for global warming is 25 times more than carbon dioxide. Approximately a third of these emissions are in the different sections of oil production and processing, transferring and storing of natural gas.   Materials and methods: The present study has been done to calculate the amount of methane emission to the atmosphere by startup of Siemens gas compressors in Iran gas transmission operation district 2. In this study, op-erational information of 25 Siemens gas Turbo compressors related to six gas transmission stations collected and with modeling conditions in PHAST, the amount of methane emission has been determined.   Results: According to the obtained data, in 2018 this district has released 140/870 tons of methane gas to the atmosphere due to the above-mentioned process. The methane emission factor for Type C compressor is 241/15 kg, for type D compressor is 341/35 kg and this factor for type E compressor is 375/48 kg.   Conclusion: The release rate obtained for each type of the C, D and E com-pressors can be used to calculate the emissions of all SIEMENS 10MV2A gas compressors of the same model in Iran.