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Jet Mixers for Mixing & Agitation of Crude Oil Storage Tanks

Raw Crude Oil is collected in large storage tanks after extraction from production sites. Raw Crude contains multiple impurities such as tar, sand, water and coke. If kept idle the impurities tend to settle and water accumulates in some pockets at the bottom of the tank. This mixture is referred to as Bottom Sludge & Water (BS&W).

Thus keeping the tanks idle and BS&W accumulation leads to the below issues

  1. When crude from multiple sources is stored into the same tank the heavier fractions tend to settle at the base and the top is concentrated with lighter fractions and homogenous crude is not obtained at outlet.
  2. Small pieces / particles from the bottom sludge break up and enter the downstream pumping equipment.
  3. Water pockets can create corrosion problems and eventually create a hole in the tank walls.
  4. The accumulation of bottom sludge reduces the tank capacity and needs to be periodically removed from the tank.

Thus agitation and proper intermixing is important for crude storage tanks to avoid the above issues and ensure uniform crude quality.

Accordingly the mixing equipment installed for a Crude storage tank needs to have below attributes

  1. Effective agitation spread uniformly throughout the tank.
  2. Effective circulation that will not allow solids to settle and keep recirculating them to the top.

Jet Mixers are simple devices that utilize liquid recirculated from the tank by a pump for its operation. When installed in a crude storage tank jet mixers suck surrounding crude oil and discharge it at high speeds back into the tank. This action displaces and moves the crude oil in the tank and when the Jet Mixer is allowed to operate for some time, this movement of crude oil creates a circulation pattern inside the tank and creates mixing and agitation.

A jet mixing system consists of multiple jet mixers installed at various locations inside the tank. It allows the agitation to be spread evenly throughout the crude storage tank. The circulation pattern is determined by the orientation of the individual jet mixers.
And the agitating intensity is controlled during operation by varying the inlet pressure of the recirculating crude.
The above attributes allow the Jet Mixing system to be a perfect solution for mixing & agitation of Crude oil tanks.

Additionally in the jet mixing system, all components lying inside the tank (Jet Mixers and Pipelines) are static in nature while the moving parts (Pumps and Valves) lie outside the tank.
Being static devices, Jet mixers have negligible maintenance requirement and can operate for many years after installation.
Maintenance is generally required for Pumps and Valves but as they lie outside the tank, maintenance can be carried out conveniently.
Thus regular maintenance does not require draining the tank and the tank can be kept in operation for years without any costly requirement for bottom sludge removal