Global pressure on the use of traditional fossil fuels and the emission of greenhouse gases such as CO2 is enormous. Consequently, the gas turbine (GT) industry is taking action. One of the key efforts of reducing CO2 emissions in gas turbines is to shift the use of natural gas (typically CH4) to alternative fuels such as Hydrogen (H2). The various gas turbine OEMs, as well as utilities and other users of gas turbines, are currently investigating the impact of firing H2 in gas turbines. A lot less focus is given to its impact on other complementary equipment to gas turbines such as Heat Recovery Steam Generators (HRSGs), while a great deal of the global gas turbine fleet is connected with HRSGs.
This paper will give insight into what the main impacts are of firing H2 in gas turbines on HRSGs. For example, the combustion of hydrogen will occur at higher flame temperatures than natural gas. One of the side effects of that fact is the production of more nitrogen oxides (NOx). Secondly, the water dew point of the flue gas increases when firing hydrogen in the GT. This means that cold parts which are in contact with flue gas will form condensation quicker. Thirdly, firing H2 adds extra volume to the exhaust gas flow compared to firing natural gas. Last, but certainly not least, are the additional safety aspects that apply when firing H2 in the gas turbine. This paper will explore design considerations for the HRSG based on the above impacts.
Sebastian Ruijgrok | Business Development Manager, Siemens Energy b.v.
Richard Saab | Sales Manager, Siemens Energy
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