CHANGING THE OPERATING PARAMETERS OF GAS DISTRIBUTION NETWORKS WHEN TRANSFERRING THEM TO THE TRANSPORTATION OF GAS-HYDROGEN MIXTURES

Abstract

The purpose of the work is to establish the regularities of the influence of the properties of gas-hydrogen mixtures on the modes of operation of existing low-pressure gas distribution networks, which previously operated on natural gas. The density and higher heat of combustion for natural gas and gas-hydrogen mixtures created on its basis are determined in accordance with the requirements of current standards and the Code of Gas Distribution Networks under standard volume measurement conditions, namely, a pressure of 101.325 kPa and a temperature of 0 °C, and a standard combustion temperature of 25 °C, taking into account the real properties of gases. The regularities of changes in calculated costs, pressure losses from friction and final pressure in a low-pressure steel and polyethylene gas pipeline depending on its load and the molar concentration of hydrogen in the gas-hydrogen mixture have been established. According to the results of mathematical modeling, analytical dependences of pressure losses due to friction in low-pressure steel and polyethylene gas pipelines were obtained as a function of the Reynolds number and the molar concentration of hydrogen in the gas-hydrogen mixture. According to the research results, graphic and analytical dependences of the initial pressure value in the steel and polyethylene gas distribution network were obtained for the full range of changes in molar concentrations of hydrogen in the gas-hydrogen mixture. As research has shown, the predicted value of the initial excess pressure does not exceed 4000 Pa, that is, it is less than the value of 5000 Pa, which is the maximum pressure in low-pressure gas pipelines. Thus, the possibility of transporting gas-hydrogen mixtures containing an arbitrary molar fraction of hydrogen through low-pressure gas pipelines at increased costs by increasing the pressure at the beginning of the network after the gas control point has been established. This will require proper adjustment of the pressure regulators and relief valves.