The production of biomethane from biogas energy costsfor the most widely used amine and water processes for extracting carbon dioxide from biogas were analyzed using computer simulation. Combined water-amine absorption method of biogas purification from CO2 wasincluded in the comparative analysis. For the CO2 content of the biogas from 32 to 42 %, the specific energy costs when using water absorption to extract carbon dioxide from biogas are, on average, in ~ 2.5 times lower than amine absorption, but the loss of CH4 by water absorption was 7.1–7.6 % due to its watersolubility with practically zero CH4 loss when using amine absorption and insignificant loss (0.17–2.8 %) using water-amine technology. Using preliminary water absorption of CO2 saved CH4 can compensate the power consumption of the biogas compressor or the heatcosts of saturated amine absorbent regenerating. This will allowto reduce energy consumption to almost equal to water absorptionone. The results of simulation of carbon dioxide extraction from biogas can be used to optimize technological absorption schemes for the production of biomethane — an analogueof natural gas. Bibl. 13, Fig. 5, Tab. 6.

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The article presents the results of the development of the modernization of the complex gas preparation installation, namely the modeling of the processes of removing heavy hydrocarbons at the stage of preparing natural gas for transportation. Heavy hydrocarbons, which are removed at this stage, become a separate commodity product in the process of processing. With the use of software systems for computer simulation of technological processes of GazCondNafta and HYSYS, a variant of the modernization of the existing installation of complex gas preparation of the gas condensate field was developed. Options for modeling technological schemes for obtaining target fractions of methane, ethane, propane, butane from natural gas, gas synthesis and pyrolysis gas are given. Bibl. 9, Fig. 5, Tab. 8.

Currently, the developed EU countries have implemented biomethane production projects from biogas, supply it to natural gas distribution grid with subsequent production of electricity or (and) heat, and use biomethane as motor fuel or supply to the gas network. It is also extremely relevant for Ukraine, supposing the problems with gas import due to Russian aggression and the presence of a large agricultural potential. The concern that arises is the rational choice of the technology for producing biomethane from biogas.The Gas Institute of the National Academy of Sciences of Ukraine has extensive experience in the development of technologies for the biogas collection, its direct usage, and CO2 extraction by the amine absorption method. Some of the technologies have been implemented at landfills in Ukraine. Data on other methods of CO2 extraction are widely available in world publications, so the authors compared the technologies from the point of view of their practical use possibility. Using computer modeling, the energy costs during the production of biomethane from biogas using the most advanced amine and water absorption processes for cleaning biogas from carbon dioxide were analysed. The combined water-amine absorption method of biogas purification from CO2 was included in the comparative analysis in which carbon dioxide was previously removed by water absorption at a pressure up to 0.3 MPa and output finally purified by amine absorption. Calculations for amine technology are verified in a pilot study.For a range of the CO2 concentration in biogas 32– 42 % vol., the specific energy consumption when using water absorption, the extraction of carbon dioxide from biogas is on average two times less compared to amine absorption, but at the same time the loss of CH4 due to its solubility during water absorption amounted to 7.1–7.6 %, with practically no losses of CH4 in amine absorption, and minor losses (0.17–2.8 %) in combined water-amine technology.The energy consumption of combined water-amine absorption is comparable to that of water absorption due to: a) reduction of heat losses for regeneration process of saturated amine absorbent, as part of CO2 has already been removed with water technology; b) using the CH4 excess to compensate power consumption of the biogas compressor during the preliminary water absorption of CO2 and/ or to compensate heat costs of the saturated amine absorbent regeneration.The results of extracting carbon dioxide from biogas processes modeling can be used to optimize technological absorption schemes for the production of biomethane, an analogue of natural gas.