Roots vacuum pump for large atmospheric and vacuum unit is a relatively advanced technology. Atmospheric and vacuum distillation is an important process of oil refining. Atmospheric and vacuum distillation unit is the leader of oil refineries and many petrochemical enterprises. The processing capacity of the unit, i.e. the primary processing capacity of crude oil, is often used as a sign to measure the development progress of the enterprise. After distillation, crude oil is separated into various oil products and raw materials of downstream units. Due to the huge amount of crude oil processed in atmospheric and vacuum distillation unit, the scale and energy consumption of atmospheric and vacuum distillation unit is huge, and its energy consumption generally accounts for about 20% ~ 30% of the total energy consumption of the refinery. Therefore, it is imperative to optimize the energy saving of the unit. In the design and operation, the recommended energy saving optimization measures are mainly the application of Roots vacuum pump in large atmospheric and vacuum units.
With the deepening of energy-saving measures in refineries and the improvement of the overall level of machinery manufacturing and maintenance, people pay more and more attention to the mechanical extractor. The application of Roots vacuum pump to replace the secondary steam extractor has achieved good results.
Roots vacuum pump structure characteristics
(1) larger pumping speed in a wider pressure range;
(2) the rotor has good geometric symmetry, so the vibration is small and the operation is stable. There is clearance between rotors and between rotors and shells, no lubrication, small friction loss, which can greatly reduce the driving power, so as to achieve higher speed;
(3) the pump cavity does not need to be sealed and lubricated with oil, which can reduce the pollution of oil vapor to the vacuum system;
(4) there is no compression and exhaust valve in the pump cavity. Simple and compact structure, insensitive to dust and water vapor in the extracted gas;
(5) the compression ratio is low and the effect of hydrogen extraction is poor;
(6) the rotor surface is a curve cylinder with complex shape, so it is difficult to process and check. In recent years, roots vacuum pump has developed rapidly at home and abroad. It has been widely used in smelting, petrochemical, electrical, electronic and other industries.
The features of Roots vacuum pump are: quick start, low power consumption, low operation and maintenance cost, large pumping speed and high efficiency. It is not sensitive to a small amount of water vapor and dust contained in the extracted gas. It has a large pumping speed within the pressure range of 100-1 PA, and can quickly remove the suddenly released gas. This pressure range is just between the oil sealed mechanical vacuum pump and the diffusion pump. Therefore, it is often connected in series between the diffusion pump and the oil sealed mechanical vacuum pump, which is used to improve the pumping capacity of the intermediate pressure range. At this time it is also known as a mechanical booster pump.
Atmospheric and vacuum distillation unit is one of the important production units in the refining industry. There are many potential hazards in production, such as flammable and explosive, toxic and harmful, high temperature and pressure, high vacuum, strong corrosiveness, and the production process has continuity, which brings great pressure to safety production. Therefore, safety work plays a very important role in petrochemical production, which is the premise and key of petrochemical production.
The biggest benefit of large-scale atmospheric and vacuum distillation unit is deep drawing. Through deep drawing, the yield of wax oil can be increased, which provides the basis for the balance of wax oil in the whole plant.
The application of Roots vacuum pump in large-scale atmospheric and vacuum distillation unit, whether in operation or in optimizing the effect of energy-saving measures, is significant. It can not only reduce the energy consumption of the unit, improve the product quality, but also increase the economic benefits.