A device for electrochemical treatment of water

A device for electrochemical treatment of water

RF Patent # 2078737. Filed 26.05.1994, published 10.05.97.

Bakhir V.M. and Zadorozhny Yu.G.

Flow-through electrochemical modular reactor – FEM-3 module. FEM-3 module, while very similar to FEM-2 module in the principle of its application in electrochemical systems, technically has an absolutely new design, and essentially differs from its prototype – FEM-2 module. Unlike FEM-2 and FEM-1 modules, FEM-3 module is devoid of problems arising in connection with the presence of bi-polar areas on the surface of external electrode, and it surpasses FEM-1 and FEM-2 modules in its mechanic, hydraulic and electrochemical reliability and durability. The Table below presents principal differences between FEM-1, FEM-2 and FEM-3 modules, which demonstrate advantages of FEM-3 module as a commercial standard all-purpose device for various types of electrochemical systems.

FEM-3 module and RPE reactors made up of units of FEM-3 modules have the following typical feature. FEM-3 modules can be used to implement any technological processes developed for FEM-1 and FEM-2 modules. Simultaneously, performance characteristics of these processes become better. However, FEM-1 and FEM-2 modules cannot be used in process flow sheets developed for FEM-3 modules either due to reasons making such replacement technically and technologically impossible, or because performance characteristics of processes implemented with the help of FEM-1 or FEM-2 modules prove to be worse than when using FEM-3 modules.

Principal technical and technological differences of FEM-1, FEM-2 and FEM-3 modules

Technical and technological characteristics

FEM-1

FEM-2

FEM-3

FEM module weight, g

220

200

130

Number of seal rings, pcs.

10

10

4

Number of anode bushings, pcs.

2

2

2

Number of cathode bushings, pcs.

0

0

2

Number of collectors, pcs.

2

2

0

Complexity of FEM module assembly

High

Medium

Low

Complexity of RPE-L -type reactor assembly

Medium

Medium

Low

Compactness of RPE-L reactor

Satisfactory.

Satisfactory

Good

Complexity of RPE-M-type reactor assembly

High

Satisfactory

Low

Compactness of RPE-M reactor

Unsatisfactory

Unsatisfactory

Good

Complexity of RPE-F –type reactor assembly

High

High

Low

Compactness of RPE-F reactor

Unsatisfactory

Unsatisfactory

Good

Possibility of RPE-S–type reactor assembly

No

No

Yes

Possibility of changing configuration of inlet and outlet connections by pivot turn of heads and (or) bushings

No

No

Yes

Probability of damaging diaphragm during disassembly

High

High

Yes

Possibility of replacing inner electrode without diaphragm removal

No

No

Yes

Risk of electrochemical anode erosion in the area of liquid feeding (discharge) to the electrode chamber of external electrode

High

Medium

No

Risk of induced polarization of the outer surface of external electrode

High

Medium

No

Probability of decreased concentration of heterogeneous structures carriers of active charged particles in areas of changed configuration of electric lines of force (in the outlet openings of external electrode)

High

Medium

no

Accuracy of co-axial diaphragm installation in the interelectrode space

Low

Low

High

Guaranteed seal-tightness of electrode chambers separation by diaphragm during assembly

No

No

yes

Possibility of spontaneous diaphragm shift resulting from seal ring deformation due to electrochemical process factors

Yes

Yes

No

Probability of deformation, embrittlement, and decrease of electrocatalytic cathode activity as a result of hydrogen pickup

High

High

No

Existence of critical zones of liquid convective flow blockage in external electrode chamber (three phases “gas bubbles-charged metal-liquid” in narrow clearances at the inlet and outlet)

Yes

Yes

No

Heat-exchange with the environment

Good

Good

Excellent

In the process of further practical work with FEM-3 modules it was realized that the development of a reliable, all-purpose and easy-to-use electrochemical reactor marked the birth of the technology of electrochemical activation in particular, and the technology of “personal” applied electrochemistry in general.