Vacuum system for oil deodorization

Composition and working principle of vacuum pump, steam jet pump and water ring vacuum pump in oil deodorization process

The vacuum system of grease deodorization process and the factors affecting its vacuum degree are introduced

1. Composition and working principle of vacuum system

With the gradual implementation of the national policy of energy conservation and emission reduction in recent years, the current popular vacuum system in the deodorization process of oil refining consists of two intermediate condensers and a three-stage steam jet pump and a water ring vacuum pump (instead of the traditional four-stage steam jet pump).

Laval nozzle is provided in the steam jet pump, and the steam flows to each injector through the shunt packet. Steam flow velocity in the pipeline for dozens of m/s, but when the steam through the laval nozzle, gas explosion, step-down velocity sometimes up to nearly 1000 m/s or so, most of the gas potential energy (high pressure) into kinetic energy (high speed), and the air entrainment deodorization tower mixed gas for energy exchange, and then through the pipe expander decelerating pressurization and the atmosphere. The secondary and tertiary ejectors are equipped with an intermediate condenser, which is sprayed with low-temperature condensed water into the condenser to achieve the purpose of condensing high-temperature steam.

2. Vacuum requirement of grease deodorization process

The vacuum normally required in a deodorizer is 200 to 400pa.

3. Main factors affecting the vacuum degree of the vacuum system

In the actual production application, the system cannot reach the required vacuum degree due to the influence of the following marginal conditions:

1) Steam pressure — when the steam pressure does not reach the design value of the system, its operating flow rate and flow rate will decrease accordingly, thus affecting its vacuum degree;

2) Temperature and flow rate of condensed water — when the temperature of condensed water is higher or the flow rate is lower, it will affect the condensation effect of the condenser, otherwise it will not only affect the vacuum degree of the condenser, but also increase the consumption of steam;

3) Steam jet pump volume — The sniffling volume of a steam jet pump depends on the amount of steam used and the amount of components that evaporate from the oil during deodorization. When the production capacity is certain, the amount of steam, the quality of deodorized grease and the effect of fatty acid supplementation will affect the pumping capacity of steam jet pump.

4) Pumping capacity of water ring vacuum pump — When the pumping capacity of water ring pump is reduced, the vacuum degree of the system will be directly affected and the consumption of steam will be greatly increased. The pumping capacity of water ring vacuum pump mainly depends on working liquid temperature, atmospheric pressure, weather humidity, air temperature and mechanical efficiency of the pump.

5) Influence of high temperature weather — As mentioned above, if the weather temperature is high, it will affect the cooling effect of the condenser and the inlet water temperature of the water ring pump, thus affecting the vacuum degree of the system.