Life cycle assessment on improvement strategies of environmental sustainability for a liquified natural gas plant in Indonesia

This study aims to assess the environmental impacts of liquified natural gas (LNG) process production, identify the increasing potential of environmental performance, publish environmental product declarations, and contribute to a national database of environmental impacts.

The analysis scope covers raw material receiving, a liquefaction process, utility, and storage and loading of the product. The assessed impacts are categorized as primary, secondary, and energy usage impacts using a life cycle assessment method that refers to ISO 14040-2016 and ISO 14044-2017 guidelines. The three methods for impact evaluation included ReCiPe 2016 Midpoint (H) v.1.03, CML-IA Baseline v.3.05, and cumulative energy demand (CED) methods.

Every ton of LNG product produced global warming, ozone depletion, acidification, and eutrophication potential of 699.31 kg CO₂-eq, 2.62 × 10⁻⁴ kg CFC11-eq, 0.4281 kg SO₂-eq, and 0.1155 kg PO₄-eq, respectively. The secondary impact of the photochemical oxidant was 0.81968 kg C₂H₄-eq/ton. Abiotic depletion potential–fossil was observed at 23.41183 MJ/ton, while non-fossil was 0.0000041 kg Sb-eq/ton. Biotic depletion potential included terrestrial, freshwater, and marine ecotoxicity produced 3.0439 kg 1,4-DCB-eq/ton, 0.0452 kg 1,4-DCB-eq/ton, and 0.0630 kg 1,4-DCB-eq/ton, respectively. Carcinogenic and toxicity impacts produced 0.0681 kg 1,4-DCB-eq/ton and 1.966 kg 1,4-DCB-eq/ton. The impact on the water footprint of every ton of LNG was at 2.6387 m³, and land use change was evaluated at 0.0883 m³a corp-eq. Analysis of cumulative energy demand identified that the LNG plant needs only non-renewable energy. The specific energy consumption is 29,151.056 MJ/ton.

This study identified that the hotspots included the steam generation unit in Utility II and sour gas absorption in all studied trains. Steam generation produces more CO₂, NO_x, and SO_x emissions. Besides, the utility applied phosphate and boiler feed water. The process of sour gas adsorption needs electricity and polydimethylsiloxane as an adsorbent.