The remaining heavy oil after oil and diesel oil is characterized by large molecular weight and high viscosity. The specific gravity of heavy oil is generally 0.82-0.95, and the calorific value is about 10,000-11,000kcal/kg. Its composition is mainly hydrocarbons, and it also contains part (about 0.1-4%) of sulfur and trace amounts of inorganic compounds.
Heavy oil, also known as fuel oil, is a dark black liquid. According to the classification method of international conventions, heavy oil is called persistent oil. As the name suggests, this kind of oil is relatively viscous and difficult to volatilize. So once ashore, it is very difficult to remove. It is mainly blended from atmospheric oil, vacuum residue, cracked residue, cracked diesel and catalytic diesel in the process of crude oil processing.
Heavy oil with a specific gravity exceeding 0.91 has a high viscosity and contains a large amount of nitrogen, sulfur, waxes and metals, and basically does not flow, and tar sands are even more immobile. When mining, some need to inject heat into the ground, such as injecting steam, hot water, or some hydrocarbons to dissolve it and increase its fluidity, while others use methods similar to mining coal.
The twin-screw pump is an ideal type for conveying various viscous media. Because of its structural characteristics and adaptability to system changes, there is no problem at all with conveying heavy oil, dirty oil and other media.
When using a twin-screw pump in heavy oil and other working conditions, special attention should be paid to the selection and configuration of the pump. Heavy oil will contain impurities and have a large viscosity range, ranging from a few to several thousand Reis. The general purpose of a twin-screw pump is The performance is relatively good, which is very suitable for this working condition. The design of the twin-screw pump body adopts a thermal insulation jacket, external gearbox and bearing, and independent lubrication, not affected by the conveying medium, there are many options for sealing design, and the selection of pump materials can be selected according to the specific chemical characteristics of materials.
The advantages of twin-screw pumps in the storage and transportation of heavy oil and dirty oil:
1. During loading and unloading, the flow range is large, and the change in the flow rate can be controlled by the speed-adjusting and variable-frequency motor.
2. It can transport oil with different viscosities in different storage tank areas.
3. Double suction structure, strong self-priming function.
4. Circular transportation between oil tanks is possible.
5. The structure is compact, saves space, and ensures the high efficiency of different stations.
6. The structure of the pump ensures low pulsation and low noise during operation.
7. For different working conditions, twin-screw pumps with different specifications can be selected with a large lead range of the helical sleeve.
8. Twin-screw pump installation method. There are many choices for the direction of inlet and outlet.
9. Safe and reliable operation, stable performance, long service life and low operating costs.
10. Driven by synchronous gears, the rotors of the twin-screw pump do not touch, allowing short-term idling.