Vol 1 Chapter 24: An evaluation of conversion of gas turbines to hydrogen fuel
Gregory P. Wotzak et al, GE Energy, USA
Abstract: Gas turbines can play a key role in reducing CO2 generation from fossil fuels. GE heavy-duty gas turbines are already in service in the chemical process industry on gaseous fuels containing up to 95% hydrogen by volume. Gas turbines are operating in integrated gasification combined-cycle refinery applications with the generation of hydrogen as a feedstock for hydro cracking. However, these process applications usually include other fuel constituents, which prompted the need for a study of gas turbine response when coupled to specific processes that are applied to CO2 capture. Relative to improving the economics of CO2 capture, the feasibility of converting existing natural gas units is an approach that needs to be examined. This study evaluated the suitability for hydrogen fuel utilization with GE’s Frame 5002C and Frame 6001B gas turbines at the BP Prudhoe Bay facility. These types of machines are in wide use in industrial and chemical production applications. GE evaluated the appropriateness of seven candidate machines for utilizing high hydrogen fuels from three candidate pre-combustion de-carbonization processes. The detailed requirements definition calculations included all candidate fuels.
The three fuel choices representative of the different hydrogen generation processes that use natural gas feedstock were screened for their combustion properties and related combustion experience. All fuels evaluated were found to exhibit sufficiently acceptable combustion properties that meet the detailed requirements.
One fuel was jointly selected by GE and the BP CO2 Capture Project team for further detailed study, with consideration of possible pre-blending fuel with steam upstream of the gas turbines for additional NOx abatement. Comparative evaluations were also continued as well with the other fuel choices.
Relative performance changes in terms of output, heat rates and emissions at three points on the operating curve (maximum, normal operating point and minimum load) were determined at full load, minimum turndown and an intermediate load. In addition, comparative performance runs were performed at full load for all three candidate fuels, with a target NOx level of 25 ppm.
The suitability of these machines was determined from the feasibility and cost of modifications to the flange-to-flange machine, controls, and fuel system to be able to utilize high hydrogen fuel.
This feasibility study for gas turbine retrofit requirements to burn high hydrogen de-carbonized fuel has determined that the conversion of any or all the Frame 5 and/or Frame 6 units at Prudhoe Bay is not only possible, but brings significant advantages in increased power and reduction in emissions.
Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project Capture and Separation of Carbon Dioxide from Combustion Sources - Volume 1
Edited by: David C. Thomas, Senior Technical Advisor, Advanced Resources International Inc, USA
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