Soroka N. Information and measurement provision for works related to decarbonization of natural gas supply

The dissertation research object is measuring the volume of natural gas-hydrogen blends for decarbonization of natural gas supply. The subject of research is the method of determining the volume of a natural gas-hydrogen blend based on the dependence between the compressibility factor of the blend on the hydrogen content and is used to implement actions to decarbonize natural gas supply. The dissertation solves a scientific and practical problem related to the need to accurately determine the real volume of the natural gas-hydrogen blend by taking into account changes in the compressibility factor caused by changes in the component composition of natural gas and the proportion of hydrogen in the mixture. The introduction substantiates the relevance of the research objectives, presents the scientific novelty, and formulates the practical significance of the obtained results. In the first chapter, the key documents of the legal regulation of the energy transition are presented, which indicate the further development vectors of the European Union and Ukraine for the sustainable development of society, and an overview of the global regulatory framework covering all links of value creation in the process of decarbonization based on hydrogen technologies are presented as well. A review of existing standards for the use of natural gas was carried out, which already have changes regarding the use of natural gas and hydrogen mixtures, or the work of technical committees in this direction is underway. Particular attention is paid to the standards for accounting for hydrogen and natural gas-hydrogen blends since accurate accounting of gas-hydrogen mixtures is necessary for fiscal operations and, accordingly, the development of the hydrogen market in the context of decarbonization of natural gas use. In the second chapter, a theoretical analysis of the suitability of existing information and measurement equipment for accounting for the volume and flow of hydrogen and natural gas-hydrogen blends is carried out. In particular, it was considered what types of meters could potentially be used in the residential, public, transportation, or industrial sectors to account for the volume and flow of hydrogen or gas-hydrogen mixtures. The main challenges related to the metering of hydrogen and natural gas-hydrogen blends were identified and it was determined which of these challenges are more crucial for specific types of meters. In the third chapter correlation methods for determining the compressibility factor of natural gas-hydrogen blends with hydrogen content up to 20% by volume were investigated. The compressibility factor, in fact, characterizes the difference between an ideal and a real gas and must be taken into account to accurately determine the real volume of a gas at a given temperature and pressure. Adding hydrogen to natural gas will change the physical and chemical characteristics of the mixture, which will directly affect the compressibility factor value. Calculations for natural gas-hydrogen blends were performed according to the AGA8 equation of state and correlation methods, in particular those described in Appendix G of SOU 60.3-100:2012, which take into account only the carbon dioxide content or the relative density of the gas mixture. The mathematical model for determining the compressibility factor was improved by taking into account the hydrogen content variable in the relevant equations. As an alternative solution, it was proposed to use artificial neural network algorithms to calculate the compressibility factor of natural gas-hydrogen blends. For this purpose, a feed-forward back propagation artificial neural network was created and trained. The analysis of the nature of the deviations and comparison of the results of determining the compressibility factor based on the ANN showed the feasibility of their practical application for determining the compressibility factor in the tasks of decarbonizing natural gas supply. In the fourth section, the calculation of the real volume of gas at standard conditions (0.101325 MPa; 20˚С) was carried out, taking into account the compressibility factor calculated using existing methods in accordance with SOU 60.3-100:2012, modified equations, and artificial neural network algorithm. Based on these calculations, a code was developed to calculate the compressibility factor and to determine the real volume of the natural gas-hydrogen blend at standard temperature and pressure.