The optimal dispersion water-oil emulsion preparation unit
for electric desalting plant (CDU)

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Equipment use cases and functions

This device is aimed at boosting efficiency of crude oil desalting processes that occur inside an electric desalting plant. This effect is achieved by creating a water-oil emulsion with optimal dispersion properties which facilitates processing inside an electrostatic coalescer. ? This results in higher desalting and dehydration figures of the raw feedstock as compared to common processing practices.

Principle of operation

The specially designed adjustable pressure ratio valve (1) and the custom static mixer (2) compose a single unit, which can be controlled by oil consumption rates or several other measured parameters available at specific refinery plants.

Fact sheet

The main cause of corrosion in oil processing equipment is high concentration of mineral salts in crude oil (mostly chlorides) that are accumulated in layer water inclusions. Water is naturally ingrained in crude oil forming of a fine emulsion (with globules 1-20 µm in size).

The most common and viable method of layer water removal from the crude oil stream is processing by the high-intensity electric field using special equipment: the electrostatic coalesce. An important drawback of the EOD-processing is its inability (or at least substantial difficulty) to eliminate water globules 1-8 microns in size.

So as to increase the size of these water globules fresh water is added, which when mixed with layer water, theoretically transforms original fine emulsion into the emulsion with larger size water globules. On most types of EOD best dehydration figures are observed for globule sizes of 10-50 microns. This proves to the importance of obtaining water-oil emulsion with a predetermined degree of dispersion.

Traditionally, the flush water is dispersed in the crude oil after dosing and is mixed by a sufficiently large pressure drop on the mixing valve. Water-oil emulsion created tis way is characterized by unstable and far from optimal dispersion of salt water globulesthat, consequently, results in excessive concentration of corrosive salts in a form of permanent inclusions.

1-20 µm

the size of water globules containing
mineral salts found in crude oil

10-50 µm

the optimal size for globule
removal with EOD-processing

The S-Mix Unit implementation effects at electrostatic desalting plants

  • Decrease of corrosiveness,
    increase in quality of raw materials
    for further processing
  • Decrease of raw oil pump energy consumption
    due to a substantial reduction of pressure
    drop inside the mixing valve
    of electrostatic desalting plants
  • Increase of predictability
    for demineralization processes, possibility
    of the qualitative response
    to changing raw material quality

The degree of oil dehydration when using a static mixer demonstrates
an approximately two-fold increase in performance compared to effectiveness
shown by conventional systems. What is more the increase in performance
for desalting , as a rule, is even greater than that of dehydration.

S-Mix block provides:

1.More intense mass exchange between flush water and layer water.

2.The most optimal size of salt water globules in oil
with an average diameter of 10-50 µm (for EOD removal).

3.Improvement in stability of right-sized globule formation,
even in case of substantial changes in crude oil consumption.

4.Even distribution of salt water globules in raw material flow.

5.The best distribution of flush water inclusions across
the pipeline section prior to EOD feed.

6.6. The optimal distance between globules for their coalescence
under the EOD electric field.

Model of globule distribution inside the S-Mix-Ds mixer

Key operational parameters*
and performance figures

* working range may be changed in accordance with custom Technical specification

  • Consumption of raw materialsUp to 1200 m3/h
  • Dispersion of water phase10-55 microns
  • Working pressureUp to 50 bar
  • Available diametersDN150 – DN800

The company’s skills set

The VDK company has more than eight years of experience and specializes
in agent injection and batching systems, mixing of liquid
and gaseous substances systems, alignment of the concentrations and temperatures fields systems.
A full production cycle is implemented in the organization: from the idea
to the release of the final product. There is own engineering team and production base, implementation process
and after-sales support of products are efficient.


We have cooperated with research organizations in the industry of All-Russian Research Industry in oil refining and Gubkin Russian State University of Oil and Gas. Among our customers, there are leading enterprises of chemical and petrochemical industry:

  • ZapSibNeftehim-2
  • PhosArgo
  • Shchekinoazot
  • BSK
  • Uralkali
  • Kaustik
  • Khimprom
  • RusVinyl
  • Usolskiy Potash (EuroChem)
  • Rosneft
  • Tatneft
  • You can find the full list
    of our customers in our references

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