Thursday, November 26, 2009

Gas Turbine-Based Plants Utilizing Fuels Other Than Natural Gas

While natural gas and light oil distillates are the preferred standard fuels for gas turbines, many other fuels have been used successfully. Such fuels include: low Btu gases; ash-forming fuel oils (such as crude oils and heavy oils), naphtha, condensates and gases from iron and steel industries. These fuels are often available in developing countries when higher quality fuels are not. Market Demand Due to the variety of application, reliable statistics on the extent of non-natural gas fired turbines in operation are not available.

Up to 25% of the gas turbine output (in MWs) to be built in the next 10 years could use non natural gas fuels. Naphtha and condensates are expected to be the dominant fuels in this category with a few thousand MW of new capacity being added every year.

Design and operation of these plants requires more attention than natural gas fired plants particularly in relation to fuel properties such as calorific content, density, chemical composition including concentration of contaminants, as well as different combustion behavior (e.g. ignitability, flame velocity and stability) and plant emissions. Technological adaptation and additional equipment and operational requirements are necessary to cope with these difficult fuel properties. These include GT layout ( compressor and turbine) for the changed mass flows, different burner technology (burner design and burner nozzles), additional start up/ shutdown fuel system and safety measures. Performance, availability and operation & maintenance (O&M) expenses will be affected.

Sourceturbineonline.com

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