WELL-TO-WAKE CARBON INTENSITY ASSESSMENT OF JET A-1 FROM QATAR CONDENSATE REFINING: BASELINE CASE AND DECARBONIZATION RETROFIT OPTIONS

Abstract

The aviation sector remains difficult to decarbonize because commercial aircraft still depend on high-energy-density liquid fuels and long-lived infrastructure. In that context, lower-carbon aviation fuel (LCAF) provides a near-term pathway for reducing lifecycle greenhouse gas emissions while remaining compatible with existing aircraft, storage, and distribution systems. This thesis evaluates the lifecycle carbon intensity of Jet A-1 produced from Qatar’s North Field condensate at the Ras Laffan refinery and tests whether this refinery-derived pathway can satisfy the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) eligibility requirement for LCAF. Under CORSIA, a fossil-derived aviation fuel must achieve at least a 10% reduction relative to the 89.0 gCO₂e/MJ conventional jet-fuel comparator, corresponding to a target of 80.10 gCO₂e/MJ. The study combines well-to-wake lifecycle assessment, Aspen HYSYS process simulation, and lower-heating-value-based energy allocation across the refinery product slate. The assessment covers upstream production, feedstock transport, refinery processing, product distribution, and final combustion, using 1 MJ of Jet A-1 on an LHV basis as the functional unit. Particular attention is given to the brownfield character of the Ras Laffan refinery, where retrofit decisions must be judged not only by gross carbon removal but also by feasibility under existing space, utility, and integration constraints. The baseline analysis yields a site-specific WTW carbon intensity of 83.73 gCO₂e/MJ for the current condensate-to-jet pathway. This is below the generic fossil comparator, but it remains above the LCAF threshold. Two retrofit options are then evaluated. Retrofit Option 1 applies conventional monoethanolamine (MEA) post-combustion capture to the main refinery flue-gas sources. Although this option removes 5.757 gCO₂e/MJ in gross terms, the associated conditioning, regeneration, and CO₂-handling penalties add 3.4923 gCO₂e/MJ, leaving a final pathway CI of about 81.46 gCO₂e/MJ and therefore failing to meet the target. Retrofit Option 2 uses a source-matched hybrid architecture that combines CycloneCC for dilute furnace flue gases with high-pressure amine absorption for the more favorable WGSR-derived CO₂ stream. On the adopted basis, this configuration reduces the final WTW carbon intensity to 79.77 gCO₂e/MJ, crossing the CORSIA threshold by a narrow margin. The results show that, in a brownfield refinery, LCAF eligibility depends not simply on adding carbon capture, but on choosing source-specific technologies that minimize internal energy penalties and preserve the net lifecycle benefit.

Date of Award	2026
Original language	American English
Awarding Institution	HBKU College of Science and Engineering