Screw Vacuum Pump for Gasoline Vapor Recovery

According to statistics, gasoline has to go through at least four storage and loading and unloading links from the oil depot to the end user consumption.

In these links, due to factors such as ambient temperature, air pressure, and changes in the volume of gas and liquid phases in the container, some of the oil and gas will enter the atmosphere due to volatilization, resulting in loss of oil and gas.

The oil and gas loss during storage is mainly related to the saturated vapor pressure of the light hydrocarbon oil and the volume change of the gas and liquid phases in the container.

Under the same conditions, the smaller the oil density, the higher the saturated vapor pressure, and the greater the evaporation loss of oil and gas. The greater the volume change of the liquid phase, the greater the loss of oil and gas evaporation.  


Dry screw vacuum pump is a key equipment in the gasoline vapor recovery device. The gas pumped is easily volatile gasoline vapor, and the main components are gasoline vapors such as C4, C5, and C6.  

Usually, the operating temperature of the pump is required to be controlled below 80°C. However, the operation of the pump cannot be reduced to such a low temperature by relying only on the cooling of the pump body. In addition, cooling water cannot be provided in most sites, and the coolant that can be provided is gasoline.

In order to reduce the operating temperature of the pump, in addition to injecting gasoline into the pump body, the most effective method is to inject an appropriate amount of gasoline into the pump cavity (at the highest temperature point) to evaporate and absorb heat to reduce the temperature in the pump cavity.  

Since the condensed gasoline of the screw vacuum pump will accumulate at the exhaust port of the pump during the oil vapor recovery process, this liquid accumulation phenomenon will cause abnormal vibration and noise of the pump, so it must be discharged in time.

Following is improvement measures.  

Measure 1: The exhaust pipe of the pump is inclined downward, and the position of the exhaust pipe is lower than the position of the exhaust port of the pump.  

Measure 2: Install a circulating pump at the exhaust port of the pump or the lowest position of the muffler to eliminate the accumulation of liquid.  

Measure 3: Install a one-way valve at the exhaust port of the pump to prevent the condensate from flowing back into the pump cavity due to the siphon phenomenon when the pump stops running.  


The application of screw vacuum pump in gasoline vapor recovery is to adsorb and filter the organic waste gas discharged from the industrial production process, and can turn the organic matter in the waste gas into liquid for recycling. The recovery efficiency is as high as 95-98%. At the same time, it has good economic and ecological benefits in reducing the evaporation loss of oil products.


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