Tag Archives: oil reclamation

Oil filtration

During operation, transformer oil accumulate contaminants, which can form various chemicals. These substances reduce the oil’s performance and are, of course, undesirable.

Operation of the transformer becomes unstable. To prevent this, transformer oil is filtered and purified. Some of the methods are discussed in more detail below.

The first stage of transformer oil purification is mechanical. This is a superficial treatment to remove particulate matter and water. The next step is deeper purification performed in vacuum with heating.

The first two stages are, in fact, preliminary. The main process involves various chemicals.

One of the methods is purification of oil with a 98% sulfuric acid solution.

In comparison to other chemical purification methods, the use of sulfuric acid has a significant drawback. Beside reacting with the contaminants, the acid also adversely influecnes the structure of the oil, making it somewhat unstable. Additional processes are required to resolve that problem.

The nature of selective purification is evident from the title. Speical solvents are introduced into the oil to remove specific impurities.

De-waxing is another widely accepted process. In this process, oil is treated with special solvents: acetone, toluene, bensol etc, to remove solid contaminants.

It should be noted that chemical methods influence oil’s stability, but extend the oil’s service life at the same time.

It should also be remembered that any purification process should end with finishing purification, closing the cycle of oil processing and filtration. This is usually done by contact method.

This means that the oil is mixed with special materials, usually clay or bleaching earth. The materials are then mixed and heated. Heating facilitates acviation of all sorbents in the clay.

These absorbents capture contaminants. Deep filtration separates oil from the clay. When selecting adsorbent, it is necessary to pay attention to the content of moisture. It should be suffucient to make production efficient and to make processed oil compliant with specifications.

The most interesting technology today involves the use of bleaching clays (Fuller’s earth). Globecore manufactures a range of CMM type units for filtration of various oils with the use of Fuller’s earth. The advantages of the design are the ability of multiple reactivation of the sorbent, mobility, simplicity of operation and high quality of the output product.

Downtime is significantly reduced by the ability to reactivate the sorbent without the need for frequent replacement, thus increasing process efficiency.

Daria Shaddad Discusses the Seminar’s Program with Jordanian Collegues

The participants at this forum were most interested in GlobeCore’s CMM-R mobile oil regeneration plant.

The CMM-R plant, as part of the GlobeCore Service Life Extension Program, extends the service life of electric power transformers by restoring dielectric strength and chemical composition of the transformer insulating oil.

The main advantage of CMM-R unit is its capability to regenerate insulating oil in the transformer online and while energized.

Other products presented at the forum were the UVM-4/7 line of industrial oil purification plants, as well as the BV vacuum section line of products designed for the removal of various contaminates and gas products from transformers.

During the forum, which lasted for one and a half hours, the participants asked many questions and participated in a discussion regarding the equipment presented.

The Jordanian participants were especially interested in the automatic “sorbent reactivation” technology featured in the CMM-R units, as well as the capability of the CMM-R plants to regenerate silicon oils.

Automated Oil Purification Unit Sold

In 2014 our company supplied and commissioned an automated mobile oil treatment unit, the GlobeCore CMM-0.6A.

The GlobeCore CMM-0.6A performs removal of solid contaminates and vacuum drying of transformer oils with viscosity up to 70 cSt at 50°С/122°F.  The CMM-0.6A purifies transformer oil by passing the oil multiple times through the filter section.

The GlobeCore CMM-0.6A unit is completely automated.  A special GSM module allows remote control of the unit by cell phone (start, stop, receipt of error messages and process parameters as a text message etc).

Down time is minimized, emergency stop can be engaged without delay and labor costs are reduced.

The CMM-0.6A plant can be used during installation, repairs and operation of transformers, oil switches and other similar equipment.

Its time to get with the Process.  The GlobeCore Process!

Quality Assurance: Methods of Transformer Oil Testing

The performance characteristics of transformer insulating oil are monitored and tested at several stages during its service life.  Regular monitoring of the oil’s quality and condition is a part of the process of servicing electric power equipment. The condition of the oil, its purity and contamination level will greatly help in indicating the condition of the transformer’s solid insulation.  It is therefore, essential to the life of the transformer to periodically monitor the condition of the insulating oil.  The heart of the transformer is the solid insulation, but the insulating oil is the life blood of the transformer.  Without the life blood, the heart will die.

The ability of insulating oil to maintain its original performance characteristics during long term operation of electric equipment is referred to as “oil stability.”  If the electric power equipment has no defects and operates in accordance with design and expectations, the performance characteristics of new oil will change and degrade slower.  When new, transformer oil has a very light color and complies with performance standards that include dielectric strength and other important characteristics.  During the course of the oil’s service life, the stability of the oil decreases and visible changes occur and oil’s color slowly becomes darker and darker.

Contaminated oil usually has a high ash content, increased acidity and presence of low molecular acids.  Acidic sludge forms in contaminated oil and aggressively attacks the cellulose insulation and reacts with the metals of the transformer’s other internal components.

Timely oil monitoring and oil analysis programs can identify when the oil needs to be changed or serviced through an oil purification and/or oil regeneration process.  Servicing the oil before it becomes aggressive against the solid insulation is the key to extending the service life of your transformers.

The main physical and chemical properties tested are the oil’s dielectric strength, dissipation factor, flashpoint, color, amount of solid particulate matter, water content, gas content and the oil’s acid number.

Dielectric strength is one of the most important indications of oil stability and this is often the first test performed.  The “dielectric breakdown test” is calculated as an average of five breakthroughs achieved in a standard discharger with two electrodes submersed in the oil at 2.5 mm distance from each other.  Six breakthroughs are achieved in the test and the last five are averaged.  If the oil is fresh, the lowest allowable breakthrough voltage is 30 kV.  In some transformers, that meets the minimum operating standard.

Decreasing dielectric strength is caused by contamination of the oil by gas, moisture, cellulose fibers or other particulate matter.

A similar process is used to calculate the oil’s “dissipation factor.”  It is the the oil’s ability to neutralize energy, prevent breakthroughs and cool the transformer.   It is a characteristic of the oil’s quality and purity and acidity.  In general, an increased dissipation factor means degradation of the oil’s dielectric capabilities.

The color of transformer oil changes from light yellow to cloudy brown under the influence of temperature, contaminants and electric current.  The color is not in itself an indication of any specific problem, but a dark color is usually an indication of aged and/or contaminated oil.

The presence of solid particles in the oil and the acid number of the oil are two related oil purity characteristics.  Unsolved materials accumulated in the oil in the form of sludge or suspended particles (fibers, dust, solved paint, metal particles, ash etc) degrade the oil’s dielectric properties and promote oil oxidation.  The more particles that are present in the oil, the faster the oil ages. The acid number is expressed as milligrams of KOH required to neutralize all acids in a gram of oil and indicates the degree of oil aging.  A normal and acceptable acid number is 0.25 mg KOH/g, while the limit of contaminant content is 515 parts per million (ppm).

Moisture and gas content in transformer oil must be tested for thoroughly.  Water and gases are very damaging to your transformer insulation system and are two main cause of the oxidation process and oil aging process.

Moisture and water content is measured as amount of hydrogen when reacting the oil with calcium hydride in a certain period of time.  Gas content is measured by an absorptiometric analyzer or a chromatographer.

The oil’s flashpoint and the oil’s setting point are two indications of the general fire safety of the oil and the oil’s ability to operate in adverse temperature conditions both hot and cold.

The are distinct advantages of testing and analyzing transformer oil before starting your electric power equipment and during scheduled maintenance events.  Oil testing allows the operator to determine the equipment’s operating efficiency, conditions and the possibility of future malfunctions.  If the purity and quality standards are followed, the equipment will be less likely to experience failures and downtime and unscheduled maintenance and repair costs.

Reclamation of oil

Oil reclamation today is a very interesting and important subject. Oils can be reclaimed in a number of ways by different equipment and to varying extent.

Oil reclamation equipment developed and built by GlobeCore varies widely in terms of applications and reclamation degree:

  • oil regeneration
  • heat and vacuum purification of oil,
  • purification of oil by adsorbents
  • drying of transformer windings,
  • dehydration of oil,
  • degassing of oil,
  • reactivation and preparation of sorbents, including full regeneration of MINERAL oils with color lightening.

The following is a brief list of GlobeCore’s equipment for oil reclamation and other applications.

  • Themovacuum oil purification units, mobile oil plants: СММ-0.6; СММ-0.7(Р); СММ-0.6; СММ-1.0; СММ-1.7; СММ-2.2; СММ-4.0; СММ-4.3 and some other models;
  • Comprehensive oil restoration units, including heating, nitrogenation, drying and filtration of insulation oils: UVM-3, UVM-4, UVM-5, UVM-5М, UVM-6,  UVM 10-10, UVM 10-10В, UVM 10-10l, UVM 10-10М, UVM-12Б, UVM-12Б1, UVM-12Б2, UVM-12Б3, UVM-14Б У1, UVM-14Б1, UVM-14Б2, UVM-10-3, UVM-10-3Е, UDV-2М, PDV-Е and other range.
  • units for purification, drying and removal of solids from transformer and turbine oils – MCU-2-U1, MCU-4-U1, MCU-4С-U1,  MCU-4А,  MCU-4СА,  MCU-4C, MCU-4CF, MCU-4CS,  MCU-4CSA, MCU-А, MCU-С, MCU 4Р-N, MCU 4Р-NС, MCU 4Р-NA, MCU 4Р-NСА,  BC-N, MCU-7, FSM-2, FSMB-110М etc;
  • Sorbent regeneration systems– BR, PS-1, PS-1А,  PS-1Е, BRPS, MCU-4Р-BR, zeolite drying cabinet
  • Systems and vacuum sections for drying of solid insulation of power transformers – “Iney-4″, ” Iney-4М”, ” Iney-5″, ” Iney 5М”, ” Iney-6″, ” Iney-4.1″, ” Iney-4.1М”, ” Iney-4.2″, ” Iney-4.2М”, vacuum units BV-1 and BPR;
  • Units for drying of air to dew point below -50°С – “Sukhovey”, ” Sukhovey-4″, ” Sukhovey-5″, ” Sukhovey-4Е” with two independent heaters
  • transformer and transformer oil heating units: NTML, NTML-160М, NTML-80М, NTML-120М, NTML-200М, NTML-240М, NTML-150Е, for parameters of processed oil: solid content no more than 5 (10) ppm, filtration from 5 to 20 micron
  • oil filtration systems – FUM-P, FUM-А, customized drying and solid removal systems for mineral oils up to 50 m3/hour capacity, purity class from 7 toо 11, filtration ratios from 20 to 2000, filtration fineness 1, 3, 5, 10, 20 and 40 micron;

The full range of GlobeCore products is presented in the attached file, and can also be seen in the company’s website at www.globecore.com

The company has a global dealership network, and the products are supplied to more than 80 countries. Certified explosion protection option is available. Production certified as per ISO 9001 – 2000.