Yuriy V. Goncharenko

Equipment for fast oil and adsorbent regeneration

 

     It is well-known, that one of the most critical problems in hi-power transformers usage is connected to quality of transformers oil. During the transformer operation oil absorbs atmospheric moisture and its dielectric strength decreases. To reduce the water content in the oil it is pumped through the tank containing the adsorbent such as zeolite or silica gel. So the problem with oil is solved, but we have new problem: what we should do with used adsorbent?
    There are a plenty ways for adsorbent regeneration. In this review I will observe briefly the method of adsorbent drying by electromagnetic field.

 

    When we dry substances by ordinary way (using hot air or electric heaters) the enerWater flowgy comes in to the granules from outside of them. So, energy gradient in the granules is opposite to water flow (fig A.). In the case of electromagnetic heating we heat the absorbed water and energy gradient is codirectional to water flow and process of dewatering will be more effective (Fig B.).

 

    We came to next problem: how to make the uniform field and power distribution? On the follows figure you can see a power distribution in few types of regeneration cartridges. This figure shows, that the best power distribution can be obtained using four-ribbed coaxial resonator.

RMS distribution

RMS distribution in simple, four-ribbed, and  eight-ribbed coaxial resonator 

      On this figure you can see the CAD model of this resonator. The shape of ribs allows matching an impedance of the resonator with the output resistance of the power generator. 

CAD model of four-ribbed coaxial resonator 

The sorbent regeneration by proposed technique can increase the initial sorption capacity, prolong the life of sorbent, decrease a regeneration time and decrease the total energy consumption.

And a small summary: There are 3 key moment of the proposed technique: we heat a water, not an adsorbent. We try to get a uniform power distribution field. We dont reload the sorbent from filter to regeneration equipment. So, if the case of your filter is metal and hermetic it will be a possibility to apply our technique at your equipment without strong modernization.

 Specification:

  • Oil regeneration mode (after one pass):

    • Performance:  1.5m3/h

    • Moisture content: <5mg/kg (while initial value <100mg/kg)

    • Withstand voltage: >70kV;

    • Contamination: < 10mg/kg

    • Power of oil-heater: 30kW; maximum total power consumption: 35kW

  • Sorbent regeneration mode

    • Mass of zeolite NaA in the cartridge: 40kg

    • Time of regeneration 4-6h

    • Regeneration temperature: 300C (for new),  180C (for used)

    • Air pressure in the cartridge - 10kPa

    • Residual moisture  0.4%

    • Microwave power: up to 2kW; total power consumption: 6kW
       

CONCLUSIONS: 


     Application of the presented equipment allows to:

  • Increase the initial sorption capacity of the new zeolite in 15-20%

  • Increase the number of cycles of zeolite usage from 3-4 to 8-10 (in comparison to the method of drying by heating coils or hot air).

  • Decrease the time of sorbent regeneration from 15-20h to 4-6h  (in comparison to the method of drying by heating coils).

  • Decrease the total energy consumption up to 4 times (for sorbent regeneration mode).  

     

We are interesting in collaboration in following ways:

  • Technology transfer

  • Automatization of technological process

  • Development of high frequency and high power MOSFET generator 

   

 

Image gallery

 Experimental setup:  1 - High frequency generator;  2 - power supply;  3 - condenser;  4 - control unit;  5 - matching device;  6 - cartridge for oil and adsorbent regeneration.

High frequency generator and power supply (rack mount version) 

Senior researcher Volodimir Gorobets and engineer Michael Golovko are installing the high-power signal generator. 

     Industrial equipment for regeneration of transformer oil working on the two-cartridges scheme:one cartridge is used for transformer oil regeneration,second  for sorbent regeneration. After the regenertion of the sorbent in the second cartridge,this cartridge substitutes the first one in the scheme of recovery of the transformer oil.

Industrial equipment  

Co-Authors of project:

      • Professor Felix Kivva (Head of Department "Radiowave propagation in natural media" IRE NAS of Ukraine)

      • Dr. Volodimir Gorobets (senior researcher IRE NAS of Ukraine)

      • Dr. Yuriy V. Goncharenko (senior researcher IRE NAS of Ukraine)

      • Sergey Zotov (associate researcher IRE NAS of Ukraine)

      • Michael Golovko (engineer, IRE NAS of Ukraine)

      • Alexey Kovorotniy (junior associate researcher IRE NAS of Ukraine)

      • Alexander I. Govorishev (Deputy director Setra LTD)

 

This project can not been performed without strong collaboration between IRE NAS of Ukraine, National Academy of science of Ukraine and Setra LTD

Additional information: