【Basic Knowledge Activity】In the petrochemical industry, what are the indicators that reflect the evaporation properties of gasoline as part of the ‘basic knowledge’?

For gasoline to be usable properly, it first needs to have good evaporation properties. It refers to the property of gasoline changing from a liquid state to a gaseous state, and is known as the volatility of gasoline. It refers to the ease with which gasoline evaporates in the carburetor. It has a significant impact on engine startup, warming up, acceleration, air resistance, fuel consumption, etc. 1) Gasoline with good volatility vaporizes easily, mixes uniformly with air, resulting in a combustible mixture that burns rapidly and completely. This enables the engine to start easily, accelerate promptly, and transition smoothly between different operating conditions. Mechanical wear is reduced, and gasoline consumption is lowered. 2) If the volatility of gasoline is poor, it is difficult to start the engine at low temperatures. Fuel consumption increases. Unburned oil droplets reduce the sealing performance of the cylinder, thereby decreasing the output power. It can also contaminate the engine lubricant, increasing engine wear and lubricant consumption. 3) Excessive volatility of gasoline leads to increased evaporation losses during storage, gas blockages in the fuel supply system, and overload of the carbon canister in electronic fuel injection engines. Currently, the indicators used in **standards to evaluate gasoline evaporation are: boiling range and saturated vapor pressure.** l) Boiling range: The boiling range is the temperature range that indicates the evaporation characteristics of a petroleum product, as determined by its initial boiling point and final boiling point under specified conditions. The boiling range is used to determine the amount of light and heavy fractions in petroleum products. The boiling range of gasoline clearly indicates its evaporation properties when in use. The initial boiling point and the 10% distillation temperature indicate the amount of low-boiling, light fractions present in gasoline. When the initial boiling point and the 10% distillation temperature are too low, gasoline has high volatility, which can lead to vapor lock; when they are too high, gasoline’s volatility is low, making it difficult to start the engine in winter or when the vehicle is cold. The 50% distillation temperature indicates the average volatility of gasoline, and it can affect the engine’s acceleration performance. A lower 50% distillation temperature means better volatility of the gasoline, which in turn results in better engine acceleration and more stable operation. The 90% distillation temperature and final boiling point indicate the content of heavy fractions in gasoline that are difficult to evaporate and cannot burn completely. These two low temperatures indicate that there are fewer heavy components that are difficult to evaporate, allowing for complete combustion. Conversely, this indicates that there are many heavy components in the gasoline, preventing it from evaporating and burning completely. As a result, fuel consumption increases, emissions rise, and operation becomes unstable; furthermore, unburned fuel may flow into the crankcase, diluting the lubricating oil and accelerating wear on the machine components. The gasoline residue index indicates the amount of the heavy components in gasoline that are least prone to evaporation, as well as the amount of oxidized gel-like substances formed during storage. High residual levels can lead to increased carbon buildup in the combustion chamber and valve components, as well as severe gumming in the intake system and carburetor throat, thereby affecting the proper operation of the engine. 2) Saturated vapor pressure: Under specified conditions, in an appropriate testing apparatus, when the oil is in equilibrium between the gas and liquid phases, the maximum pressure exerted by the vapor at the liquid surface is referred to as the saturated vapor pressure. Saturated vapor pressure is used to evaluate the evaporation intensity of gasoline. A high saturated vapor pressure value indicates a high content of light fractions in the gasoline, which gives it good volatility. As a result, there is a greater likelihood of vapor lock occurring in the engine during use. Additionally, there is a higher tendency for loss of these light fractions during storage and transportation. However, the engine starts more easily.

What are the indicators that reflect the evaporation properties of gasoline? Answer: Octane rating and saturated vapor pressure

The volatility of gasoline is measured by three parameters: boiling range, saturated vapor pressure, and gas-liquid ratio. Among them, the saturated vapor pressure is the most intuitive. :lol @chunhui1009 @sdshihua @slll611 @zls1457 @Guan Gongyu @Linlin Shangshang @Ma Yiyi @Zhang Jun_nLlUg @SingingOnlyEchoes

The indicators reflecting the evaporation properties of gasoline are: boiling range and saturated vapor pressure.

The indicators for evaluating gasoline evaporation are: boiling range and saturated vapor pressure.

The volatility of gasoline is measured by three parameters: boiling range, saturated vapor pressure, and gas-liquid ratio. Among them, the saturated vapor pressure is the most intuitive.