CONTROL OF GASOLINE VAPOR CONTENT IN ORGANIZED EMISSIONS OF GAS STATIONS

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Goal. To theoretically justify a method for controlling the content of gasoline vapors in the organized emissions of gas stations across the full range of possible concentrations, in order to determine the volume of petroleum product emissions into the atmosphere. Methods. The work uses analytical methods of researching the processes occurring in thermocatalytic sensors, based on the main provisions of the theory of heat and mass transfer and molecular diffusion in gases, evaluation and generalization of research results. The results. It was established that the heat release on the working thermocouple depends on the mass of the fuel components and the product of the lower heat of combustion of the component and its diffusion coefficient. The highest sensitivity of the sensor is characteristic of the most volatile components of gasoline (pentane, benzene, toluene, etc.). For heavier hydrocarbons, the sensitivity of the sensor decreases. The output signal of the thermocatalytic sensor is proportional to the concentration of gasoline vapors in the fuel-air mixture only under the condition that the limiting agent in the mixture that determines the reaction rate is gasoline vapors. Therefore, in order to measure emissions of gasoline vapors in the entire possible range of concentrations, the mixture must be pre-prepared for control by metered feeding into a measuring chamber with both an emissions and atmospheric air sensor. It was determined that the main requirement in this case is to maintain the linearity of the sensor’s output signal across the full range of concentrations, which is achieved under the condition that the diffusion flow of fuel at the maximum possible content of fuel vapors in the emissions does not exceed 80% of the stoichiometric diffusion flow of fuel and oxidizer to the catalytic surface-active element. Scientific novelty. A condition has been established that minimizes the error in measuring the content of petrol vapors in the organized emissions of petrol stations due to composition changes. Specifically, gas analyzers should be calibrated using a petrol vapor mixture, with the heat release during oxidation on the catalytically active element being close to the average heat release from all components. Practical value. The conducted studies allow recommending thermocatalytic sensors for use in monitoring systems of organized emissions of oil and fuel facilities, which allow forming and substantiating requirements for standards of losses and maximum permissible levels of emissions, and speeding up the process of development and implementation of effective measures to reduce them. Key words: emissions, vapors of petroleum products, environment, control, methods, fuel-air mixtures, thermocatalytic sensors.