Towards alternative solutions for flaring: Life cycle assessment and carbon substance flow analysis of associated gas conversion into C3 chemicals

Abstract

Gas flaring has many environmental impacts at global and local scale. Conversion of associated gas into 1-propanol (scenario PRL) and propylene (scenario PRE) via the C123 process can be a potential solution to prevent combustion. This paper aims to evaluate the environmental performance of C3 production from associated gas compared to flaring and to identify the preferred C3 chemical for associated gas conversion. A carbon substance flow analysis (CSFA) and a life cycle assessment (LCA) were conducted. CSFA was used to map all carbon flows and to calculate the carbon emission savings and carbon efficiency. The LCA focused on the impact categories climate change, fossil resource use, human toxicity and the cumulative exergy extraction from the environment. The results of the CSFA indicate that 2.89 kg CO2 per kg associated gas could be saved in scenario PRL, when including the avoided conventional C3 production in the analysis. The LCA shows that scenario PRL outperforms flaring for climate change and human toxicity. Consequently, 1-propanol production from associated gas is the preferred alternative at the selected location. Heat integration and renewable electricity production can drastically decrease the impact of C3 chemicals production on climate change and enable CO2 emissions savings compared to flaring.