Evaluation of Greenhouse Gases Emission Inventory in Iranian Gas Transmission Facilities and Pipeline

Compete and consistent source identification, followed up with accurate emission measurement is the first but the most important step in reduction and controlling of greenhouse gases. Methane and carbon dioxide emission from Iranian gas transmission facilities is discussed in this article. All compression stations and transmission pipeline across the country are within the boundary of this research. Different emission types (fugitive, vent and combustion) in various operating modes (normal, maintenance, startup and process upsets) were considered and annual emission rates for all identified sources were measured or estimated, based on emission/activity factors methods. Stations age and capacity, types of turbines and compressors and the ratio of capacity to number of runs, were considered in statistical analysis. The results revealed 25 emission categories, among which, fugitive emission from station valves was the greatest with 37.8% share of total emission. Fugitive emission from blow-downs of launcher-receivers (20.7%), fugitive from above-ground pipelines (12.2%), combustion emission in stations (12.5%) and vent from compressor seals (10.8%) were in second to fifth order among all other emission sources.