Environmental and energy assessment of natural gas production in Thailand using life cycle assessment(LCA)technique

Abstract

In this esearch, environmental and energy assessment of natural gas prodution in Thailand using life cycle assessment (LCA) technique was conducted. The scope covered the data collection (inventory analysis) of input/output of raw materials, energy and all emissions (to air, water and soil) of three gas separation plants (GSP units 1, 2 and 3) at PTT PLC in Map-ta-put, Rayong. The data were compiled and processed by commercial LCA software SimaPro 7.0 in order to assess the environmental impacts in various categories, such as global warming, acidification, etc. Comparisons of the environmental performance among the three GSPs were also performed. The results showed that the environmental impacts of the natural gas production come mainly from the use of electircity which is supplied from two surces: an in-house gas-turbine power generator and the electricity gridmix of EGAT. It was found that the electricity generated in the GSP complex using its sale gas emits CO2 and NOx per unit much higher than that of EGAT. When comparing the three GSP units, GSP2, which has the smallest production capacity and the least complicated process, shows the lowest environmental impact. Having a CO2 removal unit installed and CO2 sold as a by-product, GSP1 registers a favorable environmental performance. The improvement can be made by adjusting the ratio of the utilization of electricity generated within the complex or from outside (EGAT). In addition, if the CO2 removal unit were to be installed in GSP2 and GSP3 this would lead to a reduction of the CO2 emission, thereby enhancing the overall environmental performance of the natural gas production in Thailand