STUDY OF THE EVAPORATION OF THE GASOLINE FRACTION OBTAINED DURING PYROLYSIS OF POLYMERS AFTER COMPOUNDING WITH OXYGENATES

The article considers the main physical properties of antiknock additives to gasoline - oxygenates, represented by alcohols (CH3OH, C2H5OH) and methyl-tert-butyl ether (CH3OC4H9), as well as their influence on such an indicator of the quality of automobile gaso- line as evaporation. It is proposed to estimate the evaporation of automobile gasoline by the fractional composition (Vt=f(tk.), % (vol.)) and the saturated vapor pressure (P37.8, kPa), which is usually measured at 37.8 °C (100 °F). It is these physicochemical quality indicators, togeth- er with the initial boiling point (tb.p.) and the content (X, % (vol.)) of oxygenates, that are the main ones for characterizing the volatility of individual fractions and mixtures. The results of experimental studies are presented, which indicate a decrease (by 6 kPa) in the value of the P37.8 indicator depending on the increase (from 55 °C to 70 °C) in the value of the tb.p. index of the b.p.-180 °C fraction. The P37.8 indicator of the specified fraction has a rather low value (45 kPa), which indicates the need to compound the b.p.-180 °C fraction with low-boiling hydrocarbons (for example, iso-butane and iso-pentane). Compounding the b.p.-180 °C fraction with 15 % (vol.) CH3OC4H9 contributes to a decrease in the value of the tb.p. mixture by 9.0 °C, and with alcohols СН3ОН and С2Н5ОН, does not affect the value of the tb.p. indicator of the mixture. With an increase in the content of oxygenates, the value of P37.8 increases (from 11 kPa to 17 kPa). The content of 15 % (vol.) CH3OC4H9 and СН3ОН increases the volume fraction of evaporation of the mixture at tem- peratures up to 70 °C, and the content of 15 % (vol.) С2Н5ОН increases the volume fraction of evaporation at temperatures up to 100 °C. It has been established that for the production of winter automobile gasolines, promis- ing oxygenates can be considered CH3OH and CH3OC4H9 (in winter, it is necessary to in- crease the evaporation of automobile gasoline to ensure quick engine start-up at low ambient temperatures), for the production of summer automobile gasoline – CH2H5OH (ethanol has a higher boiling point than most gasoline hydrocarbons, which helps prevent the formation of vapor locks in the engine supply system).