The problem to be solved by the research work

Development of scientific and technological foundations for the creation of power plants based on internal combustion engines for small-tonnage vessels running on alcohol fuel with thermochemical utilisation of exhaust gas heat, which ensures its high energy efficiency and environmental characteristics.

Object and subject of the research work

The object is the processes of conversion of alcohol fuels and energy in the formation and use of alternative fuel - synthesis gas, as well as the design features of the creation of a power plant with thermochemical utilisation of heat from the exhaust gases of an internal combustion engine.The subject is the regularities and parameters of the processes of conversion of alcohol fuels (production of synthesis gas) and energy (use of synthesis gas in the engine).

Purpose of the research work

The goal is to develop a design of a power plant for small-tonnage vessels based on internal combustion engines running on synthesis gas obtained from alcohol fuel by thermochemical utilisation of exhaust gas heat, as well as to establish the optimal parameters of such a plant that will enable efficient use in the energy sector of Ukraine and can be a competitive knowledge-intensive product in foreign markets.

Key performance indicators

List of articles in journals included in scientometric databases (Social Science Citation Index, Web of Science, Scopus and others) - 2Articles in journals included in the list of professional journals - 10Monographs and (or) chapters of monographs published in Ukrainian editions on the project topic in Ukrainian - 2Monographs and/or sections of monographs published in foreign publications in English or official languages of the European Union - 1Dissertations defended - 3Number of implementation agreements concluded - 2

Scientific results obtained

1. The article analyses the world's fuel and energy resources, which led to the conclusion that it is necessary to develop the use of alternative fuels in the power plants of small ships. In particular, ethanol can be identified as the most promising fuel for Ukraine, which has a wide raw material base. A review of possible ways of its use in piston internal combustion engines showed that the use of HC heat from gas to produce synthesis gas will increase the efficiency of engines running on ethanol, and will also allow the use of fuel ethanol in engines where its use is difficult to implement (diesel internal combustion engines for marine and stationary use).2. A mathematical model of the power plant of a small-tonnage vessel based on diesel engines running on synthesis gas with HCS of gas heat is developed, which is based on the fundamental equations of thermodynamics, thermochemistry, gas dynamics, heat and mass transfer, and takes into account the peculiarities of the process of fuel conversion into synthesis gas. The mathematical model makes it possible to calculate and study the parameters of the processes occurring in an internal combustion engine, determine energy flows and its distribution, and allows for numerous studies of processes in a wide range of operating parameters.3. The mathematical models of the elements of a power plant based on an internal combustion engine running on synthesis gas with thermochemical utilisation of exhaust heat were verified. The maximum relative root mean square error of the design parameters obtained from the model does not exceed 12%.4. It has been experimentally established that when full conversion is achieved by the decomposition reaction, all liquid ethanol entering the thermochemical reactor is completely converted into a combustible synthesis gas, the main components of which are hydrogen H2 (43 %), carbon monoxide CO (34 %) and methane CH4 (23 %), and the calculated specific lower heating value of the synthesis gas is 28.79 MJ/kg. At the same time, 4.0 MJ of thermal energy is consumed to produce 1 kg of synthesis gas.5. It was experimentally established that due to the presence of a significant amount of H2 in the synthesis gas, the ignition limits of the combustible mixture were expanded, which ensured engine operation at all load conditions with synthesis gas additives in a wider range of changes in the excess air ratio from 1.05 to 1.18. At the same time, the combustion rate does not decrease, which, in turn, does not lead to an increase in the concentration of CN in the LPG. Depending on the synthesis gas additive, a decrease in the content of harmful emissions from the LPG is observed in all operating modes, namely CO by 53.5 %, and CN by 55.1 %.6. Experimentally, it was found that with the use of synthesis gas additives obtained through thermochemical utilisation of exhaust heat, the specific effective ethanol consumption decreased by 20...130 g/(kWh) (2.5...12.4 %). At the same time, the amount of energy that must be used in the reactor to produce synthesis gas is 50...65 % of the heat released with exhaust gases in this operating mode.

Scientific results obtained

7. It has been established that the mass addition of synthesis gas to ethanol (1...10 %) can significantly improve the combustion process, with an increase in the indicator efficiency of the engine and a decrease in the specific indicator fuel consumption by 11.7 %.8. The addition of synthesis gas allows to increase the excess air coefficient α to 1.2 without reducing the combustion rate of the fuel-air mixture, which in turn leads to a decrease in heat losses from the gas, a decrease in the temperature of exhaust gases, and reduces toxic emissions into the atmosphere.9. The presence of hydrogen in the composition of synthesis gas improves the motor properties of the fuel-air mixture, namely, it allows to spend significantly less energy on the ignition of the mixture (0.23 MJ), which improves engine starting (especially in winter).10. Depending on the amount of 1...10 % synthesis gas additive to ethanol, the total combustion duration of the mixture φz decreases and is within 33...60º (for example, at 10 % synthesis gas additive φz decreases by 45 %).11. For piston internal combustion engines with forced ignition running on ethanol with synthesis gas additives, when using the CHP of gas heat, it is effective to use the reaction of ethanol decomposition, which has low energy characteristics of the chemical conversion process. Reduction of ethanol consumption is achieved at conversion rates of 30...100 % and is 1...12 % depending on the engine load.12. The rational temperature difference at the inlet to the utilisation device significantly affects the efficiency of the use of GHG heat. The range of operation of piston internal combustion engines with forced ignition at a temperature difference of 20 K is in the range of 26...100 % of the rated load, at 260 K - 94...98 %.13. The use of catalysts to reduce the conversion reaction temperature increases the efficiency of the use of HC heat by the CCU in a forced-ignition ICE. Reducing the conversion reaction temperature significantly expands the temperature difference at the inlet to the utilisation device, which reduces the specific ethanol consumption. When the conversion temperature is reduced by 50 K, the upper limit of the temperature difference at the inlet to the DT utilisation device increases by 1.23 times, and by 100 K - by 1.46 times. The minimum power value at which a decrease in specific ethanol consumption is achieved for a temperature difference at the inlet to the utilisation device of 160...260 K with a decrease in the conversion temperature by 50...100 K is reduced by 1.3...2.6 times.