Expanding fuel flexibility of gas turbines

Abstract

Gas turbines are continuous-flow engines that develop steady aerodynamics and flame kinetics. These features reduce the constraints placed on fuel properties for combustion and provide a considerable margin for clean combustion. In particular, heavy-duty gas turbines can operate on a large number of primary fuels that are available in many branches of the industry. These accessible fuels include natural gas (NG) and diesel fuel (DF), as well as a number of industry byproducts generated by the refining and petrochemical sectors, coal and oil and gas activities, steel and mining branches, and by the agricultural industry (biofuels). This fuel flexibility enhances the existing qualities demonstrated by gas turbines, such as efficiency, reliability, versatility in applications [mechanical drive, simple and combined cycle, combined heat and power (CHP)], strong integration potential [integrated gasification combined cycle (IGCC), gas to liquid (GTL)], and low emissions. As a result, gas turbines that use local fuel resources, synfuels or industrial byproducts — and are deployed in simple or combined cycles or in CHP units — can play a prominent role in the creation of reliable, clean, and energy-efficient power systems. This article provides the energy community with comprehensive information about alternative gas turbine (GT) fuels, covering volatile fuels [naphtha, natural gas liquid (NGL), condensates], weak gas fuels from the coal/iron industry [coalbed gas, coke oven gas (COG), blast furnace gas (BFG)], ash-forming oils, and hydrogen-rich byproducts from refineries or petrochemical plants. The main technical considerations essential to the success of alternative fuel applications are reviewed and key experience milestones are highlighted. A special emphasis is placed on the combustion of hydrogen in gas turbines.