Applying New Sustainability Metric in Different Natural Gas Liquid (NGL) Recovery Configurations to Extend Investment Decision and Incorporate Sustainability Analysis

Abstract

Sustainable design is considered as one of emerging research area in process system engineering (PSE) society. It extends the investment decision that focuses mainly on profitability analysis to consider other aspects such as the environmental impact and safety aspects. The sustainability dimensions such as the economic and environmental impact are considered to assess the natural gas liquids (NGL) recovery process using a new sustainability metric referred as the sustainability weighted return on investment metric (SWROIM). It extends return on investment (ROI) concept and makes use of the augmented sustainability metrics and process integration targeting (benchmarking) approaches. We adapted a sequential strategy to assess different NGL configurations. The turbo-expanding separation method and its consequent configurations, the most applicable separation technology in today's gas industry were considered to process 84000 kg/h of natural gas. We used ASPEN HYSYS V9 to simulate six NGL flowsheet configurations. Other ASPEN products such as ASPEN Energy Analyser were utilized to perform other energy saving activities to improve the design of baes case. Considering the economic evaluation first, and using the ROI analysis, IPSI-1 and GSP are competing with the original ISS configuration with 44% and 40% as estimated rate of investment, respectively. After the incorporation of the sustainability metric with some weights (e.g. 0.07 for thermal saving via heat integration and 0.3 for CO2 emission reduction) as relative importance to economic profit, both IPSI-1 and GSP configurations improved in SWROIM analysis with 47% and 42%, respectively. However, IPSI-2 showed to be promising with 10 %, a percentage incremental in SWROIM analysis in comparison to 8 % in IPSI-1 configuration for 0.45 as CO2 emission reduction relative importance. 2018 Elsevier B.V.