Introduction  With the development of "3060" double carbon target, the usage of the PV and wind power for hydrogen gas production is becoming a hot and cutting-edge direction. The combustion of natural gas mixed with hydrogen gas in gas turbine of hydrogen gas industry will become the final step to convert hydrogen into electric power. The gas turbine unit have pressure regulation station, front module and connection pipe. The front module have requirements on the flow rate, pressure, temperature and particle content. And the pressure regulation station will provide the required mixed gas to front module. The connection pipe will have a length of 1 000 m which depended on the different arrangement. The character of pressure drop and temperature drop of connection pipe will have direct impact on the interface parameter of pressure regulation station. So it is necessary to study the character of pressure drop and temperature drop of connection pipe. And it will provide a practicable solution for the future gas turbine fired with natural gas mixed with hydrogen gas.

  Method  The fuel demand was given for the H class gas turbine fired with mixture of natural gas and hydrogen gas after the simulation calculation with GT Pro software. The recommended material selection and velocity selection were presented based on required temperature and pressure drop by H class gas turbine front module and the physical character of mixed gas. The pipe pressure drop and temperature drop due to pressure drop were also calculated.

  Result  The pipe material selection, diameter selection, pipe pressure drop and temperature drop due to pressure drop of pipe are presented.

  Conclusion  For present time, the pipe design between natural gas pressure regulation station and gas turbine front module shall evaluate the material, outer diameter, wall thickness, velocity, pipe resistance, etc., each by each under the condition with hydrogen gas mixture. Thus the gas turbine can use natural gas at present phase and can be shifted to combustion with mixed hydrogen gas smoothly.