Vacuum pump in continuous oil refining process of application
In recent years, with the development of oil industry, large-scale and continuous oil refining production has become the mainstream of oil refining development, and higher requirements have been put forward for vacuum pump, the key equipment in complete oil equipment. The vacuum pump for the large continuous oil production line is characterized by energy saving, economy, vacuum stability and high vacuum degree. Recently, the vacuum pump manufactured for the 150t/d continuous refining unit meets the above requirements and achieves good economic benefits. Next, we will analyze the application of vacuum pump in continuous oil refining process.
The vacuum pump for continuous refining of large oil must have a long-term stable vacuum degree, and the vacuum pressure had better reach 133Pa. Energy saving, stability, high vacuum and other problems have been troubling oil equipment producers, requiring a long-term stable vacuum degree. Therefore, how to make the selected vacuum pump not only safe and reliable, vacuum stability, but also can save power and steam consumption, worthy of serious consideration.
First, let’s look at the four parts that are refined.
(1) degumming: the process of removing colloidal impurities from crude oil is degumming by physical, chemical or physicochemical methods. Edible oil, if the content of phospholipids is high, easy to bubble, smoke, smell when heating, and phospholipids in high temperature due to oxidation oil brown, affect the flavor of Fried food. Degumming is based on the principle that phospholipids and some proteins dissolve in oil in the state of sewage, but not in oil after the formation of hydrate with water, adding hot water or water vapor to the crude oil, heating the oil and stirring it at 50 temperature, and then standing stratification, separation of water phase, can remove phospholipids and some proteins.
(2) deacidification: free fatty acids affect the stability and flavor of oil. Free fatty acids can be removed by adding alkali and neutralization, which is called deacidification or alkali refining.
(3) decolorization: crude oil contains pigments such as chlorophyll and carotenoids. Chlorophyll is a photosensitizer and affects the stability of oil, while other pigments affect the appearance of oil, which can be removed by adsorbent.
(4) deodorization: there are some undesirable odor substances in the oil, mainly from the oil oxidation products. The method of vacuum distillation was adopted, and citric acid was added to chelate the excessive metal ions and inhibit the oxidation.
The large-scale and continuous oil processing has become the mainstream of oil processing in recent years, and the vacuum pump is also developing towards the large-scale. Due to the continuity of production, the energy saving of the vacuum pump is becoming more and more important. Due to the process requirements of large vacuum smelting vacuum pump, the requirements of blowing oxygen and rapid start during the process of smelting, so that it has different pumping capacity in different vacuum, in order to adapt to the maximum energy saving under the process requirements.
1, vacuum pump vacuum selection
Generally, 667Pa or 266Pa is chosen for the vacuum absolute pressure of oil deodorization. Previously, most of them chose 667Pa vacuum absolute pressure, which has the advantage of low energy consumption, but the disadvantage is that the deodorization time is long, and it is slightly difficult to reach the qualified smoke point index. In recent years, continuous deodorization mainly chooses the four-stage vacuum pump with a vacuum absolute pressure of 266Pa, which integrates advanced aerospace science and technology to achieve the purpose of maintaining stable high vacuum and reducing energy consumption through accurate computer calculation.
2, the selection of vacuum pump pumping volume
The pumping capacity of the vacuum pump is divided into dry air volume and water vapor volume. The dry air volume mainly comes from the leakage of the pump flange, valve and welding seam, as well as the entrained gas in the cooling water, steam and oil. The amount of water vapor mainly consists of direct steam and water in oil. The determination of their weight has a direct impact on the energy consumption of vacuum pumps. First, dry air should be selected appropriately, usually three times the maximum amount of leakage allowed in a sealed container. The volume of dry air is small, so the leaking air in the system cannot be removed in time, resulting in the vacuum absolute pressure can not reach the design target. The amount of dry air selected large, will increase the vacuum pump energy consumption, unnecessary waste. In the past, the vacuum pump equipped with oil and grease equipment imported from many oil plants was generally equipped with a small dry gas capacity in order to save energy. After several years of use in this way, the equipment would be aged and the vacuum degree would be greatly reduced with the increase of leakage, which affected the operation of the whole production line.
The application of the vacuum pump in oil refining process, the vacuum degree of vacuum pump, in addition to the above mentioned is very important to the choice of containment, technicians believe that it is more important to the choice of water steam, usually in fat weight of 1.0% ~ 5%, this creates the same production line to select the vacuum pump is put in bigger difference. Therefore, we can not ignore any of the small details that can affect the normal operation of the vacuum pump.