Crude oil mixer- Overview
Crude oil is stored in crude oil tanks for a long time, and substances such as hydrocarbons, wax, asphaltene, mud, sand, and water settle at the bottom of the tank and accumulate into semi-solid sediments. Analyzing the sediment in the crude oil tank, it was found that oil and wax account for 80% to 9% of the total sediment, while moisture accounts for 10% to 20%. There are not many sediments other than water, so the sediment contains many beneficial components that can be reused as much as possible. To solve the sedimentation problem in crude oil tanks, stirring devices have been installed on large crude oil storage tanks designed in the past. Most of the stirring devices used are blade type agitators, and the installation method of impeller agitators is to horizontally extend into the tank from the large opening on the tank wall. Through observation of the large oil tank agitators designed in the past, it was found that the impeller agitator had varying degrees of oil leakage problems, especially during operation where oil leakage was more serious and required manual cleaning, wasting a lot of manpower and material resources. In addition, there were dead zones in the tank during mixing. In addition, the mixing effect of this impeller type mixer on sediment formed over a long period of time is not significant. In order to solve these problems, a reasonable mixer design can be used for the newly designed 10000 cubic meter and tens of thousands cubic meter floating roof oil tanks. Generally speaking, after initial purification of crude oil, a 10 × 104m3 storage tank is filled with oil once, and the sludge content during storage and transportation is about 2.2% [1], with about 2200 m3 of sludge settling at the bottom of the tank. If not cleaned in a timely manner, it will cause clumping at the bottom of the fuel tank, reduce the storage space, and affect the inlet and outlet of the fuel tank. Therefore, installing a mixer on the storage tank to prevent sludge from being generated in the crude oil storage tank is of great significance for the storage and recovery of crude oil.

Common types of mixers
At present, the commonly used models of crude oil storage tanks in China are:
(1) Horizontally expanding impeller mixer, the impeller extends to the tank body, the impeller shaft passes through the cabin wall, the motor is located outside the cabin, and the propeller impeller is driven to rotate by an explosion-proof motor to achieve the mixing of petroleum products. Two or more agitators with larger diameters can be installed in the water tank.
(2) The rotary jet mixer forms an annular flow field state through an eccentric mechanism, while the directional rotation cycle forms a mixture to achieve comprehensive mixing effect.

Crude oil mixer- Equipment parameters
1. Model number
2. Rotational speed

3. Power
4. Axis length
5. Blade form, diameter, and number of layers
6. Bending moment and torque
7. Interface size
8. Installation location
9. Installation inclination angle
10. Sealing method