Greenhouse Gas Emissions Reduction for an LNG Plant - Technology Assessment Study
Authors: Subedar Afzal , Al-Sulaiti Khalifa Ahmed , Al-Rashdi Rashid M , Bawazir Ibrahim 
Published: March 2015

Abstract
Qatargas is working towards improving operational performance and energy efficiency to reduce its Greenhouse Gas (GHG) emissions. Qatargas' verified emissions inventory portfolio is providing data and trends, which are facilitating an understanding of key emission sources and areas of concern. This has provided Qatargas with a platform to progress a Technology Assessment Study with the objective of identifying opportunities to reduce GHG emissions through energy efficiency and operational improvements.
The Technology Assessment Study included development of a screening criteria based on multiple factors such as indicative capital cost (uninstalled), annual reduction potential in tonnes CO2-e per year, cost savings and indicative marginal abatement cost, technical complexity, commercial demonstration/viability and organizational capability. Based on the above criteria, various technological options were explored to enhance process optimization and improve energy utilization. Thermodynamic analyses of energy processes across operations, mass and energy balances, and subsequent SANKEY diagrams were designed to analyze energy flows and their sinks. Correlation of energy flows and emissions, and use of marginal abatement cost analysis were some of the approaches taken to develop technically and economically feasible options for potential implementation. This paper presents these options and provides details on specific projects of interest which could potentially be implemented to achieve process optimization, enhanced energy efficiency and reduced GHG emissions.

Introduction
GHG emissions are becoming more closely linked to climate change in the minds of the public, stakeholders and regulatory agencies thus motivating companies to reassess their operations, become more energy efficient and reduce GHG emissions so as to positively contribute towards mitigating the effects of climate change. Qatargas understands that its operations contribute to the overall GHG emissions of the State of Qatar and that proactive action is required to manage these emissions. In this context, Qatargas has developed a GHG Management Strategy. The details of this strategy have been provided in a previously published paper (1). An overview of Qatargas' facilities and details on the Technology Assessment Study conducted as part of Phase 3 of Qatargas' GHG Management Strategy are provided below.

Qatargas Facilities Overview
Established in 1984, Qatargas pioneered the Liquefied Natural Gas (LNG) industry in Qatar and is the largest LNG producing company in the world, delivering 42 million tonnes per annum (MTA) of LNG worldwide from its production facilities in Qatar (see Table 1 for a breakdown of Qatargas LNG facilities per operating asset). Qatargas also operates a condensate refinery (Laffan Refinery) with a daily capacity to process ~146,000 barrel streams per day (BSPD) of condensate feed to produce kerojet, naptha, gasoil and Liquefied Petroleum Gas (LPG). Additionally, Qatargas operates common product storage and loading facilities on behalf of other end users within Ras Laffan Industrial City (RLIC) as part of its Ras Laffan Terminal Operations (RLTO).