LIQUID/GASEOUS METHANOL FIRING CONCEPT IN OPEN CYCLE POWER GENERATION GAS TURBINES

In recent years, reducing carbon dioxide emissions has become a key objective in the power generation sector. Methanol, when produced from renewable sources (e-methanol or bio-methanol), can potentially achieve a carbon-neutral lifecycle. This study assesses the feasibility and performance impacts of replacing natural gas with methanol, in liquid and evaporated forms, in the Siemens SGT5 2000E open-cycle gas turbine at Killingholme. The turbine was modelled using PYTHIA, an in-house performance simulation tool developed at Cranfield University, with methanol fuel properties generated via the NASA CEA chemical equilibrium program. Analyses were conducted for liquid and evaporated methanol, with and without water. Evaporated methanol reduces fuel demand by avoiding combustion heat losses for vaporisation. Liquid methanol–water mixtures can increase shaft power by up to 13% at constant TET compared to natural gas, while fixed-power operation can lower TET by up to 80 K, extending blade life, though water may present corrosion risks. Water content shows a dual effect: in liquid form, it increases fuel flow and power output but reduces efficiency; in vapour form, it improves efficiency by up to 1.6 percentage points, producing effects similar to steam-injected gas turbine operation. In addition to methanol, hydrogen was compared. With its higher LHV, hydrogen required about one-sixth the fuel flow for equal shaft power or TET, although evaporated methanol delivered higher efficiency. The integration of a heat exchanger was thermodynamically assessed, including preliminary sizing and configuration layout, to enable start-up on liquid methanol–water and subsequent transition to vapour operation once sufficient waste heat is available, thereby enhancing both combustion and overall performance. The results confirm methanol’s viability as a low-carbon fuel for the SGT5 2000E. For the Killingholme unit in the UK capacity market, methanol offers a practical pathway to lower-carbon generation, notwithstanding current bio/e methanol production costs.