What Is the Best Method to Purify Oil?

There is no doubt that the machine and tractor stations or facilities that service oil-filled equipment always have to cope with the problem of used oil storage and disposal.  Generally, oil serves  as an insulating or lubricating fluid.

Dielectric transformer oil is used in the oil-filled electric power transformer, while motor, transmission, gear, hydraulic and industrial oils are mainly used in machines that have moving working parts that require lubricating oils and fluids.

It is clear that during its useful service life, any oil product loses its original characteristics.  The following is the list of the reasons for oil contamination:

(1)    extreme operating conditions such as high temperatures or impact load; and

(2)    impurities that get into oil during transportation or storage or as the result of the oxidation process.

Very often the impurities, accumulated in the oil, make it unfit for use before the end of the oil’s expected service life.  Undoubtedly, facilities and oil users have to seek ways to cope with this problem.  It makes no economic sense therefore, to purchase new oil each time because of the significant cost and labor involved.  Additionally, it may be troublesome for some enterprises to collect and store the used oil since it is prohibited to discharge it into the soil or water. An amazing fact, but true: One liter of motor oil is able to contaminate about a million liters of drinking water and render it undrinkable.

Every year, businesses and facilities generate millions of tons of industrial waste and the failure to manage this waste has the potential to cause a global environmental disaster.   The collection of waste will not contribute to the solution of this problem because the majority of enterprises do not have special storage areas for used oils.  Additionally, it is very expensive to deliver the used oil to used oil processors.  It is therefore, necessary to find new and revolutionary solutions with financial gains and reduced environmental risks.

So, the most optimal solution to this problem is to remove mechanical impurities and restore performance characteristics of the oil without the need to replace the oil.  According to the recognized classification that exists today, all mechanical impurities are divided into such groups as:

(1)    physical;

(2)    chemical; and

(3)    physico-chemical.

Unfortunately, there is no universal method of oil purification that is capable of removing all types of impurities.  We will consider therefore, all possible  purification methods that are applied to remove the particular types of impurities.

Water, gasses and mechanical impurities should be removed to restore the performance characteristics of the oil.  The reduction of the acid number takes place if oil product has been in service for many years without any type of purification processing.

Water Removal. Water may be removed from the oil by centrifugal purification, adsorption purification, and thermal-vacuum drying.  From a technical point of view, the centrifugal purification is driven by high powered centrifuges.  This purification method consists of separating different fractions of non-homogeneous mixtures when exposed to centrifugal force.  Perhaps one of the undeniable benefits of this type of purification is its relatively high water removal rate.

There are also some potential disadvantages that you should be aware of:

•    low purification rate;
•    the complexity of equipment and low operational reliability of the centrifuges; and
•    operator presence system.

Adsorption Purification is based on the ability of some substances to take up water and other impurities.  Though this method is characterized by a mostly trouble-free operation, it has the following disadvantages:

•    the need to dispose of adsorbers harmful to the environment;
•    high-quality inlet oil; and
•    low productive capacity.

Thermal-Vacuum Drying consists of separating water and oil because of their different boiling temperatures. The watery oil is supplied to the special low-pressure container where water evaporates at ambient temperature.

The following is a list of the advantages of thermo-vacuum drying:

•    high purification rate (up to 10 g/t);
•    high operational reliability and easy-to-use equipment; and
•    automated process.

A relatively small water removal rate is considered to be the only disadvantage of this method of purification.   Additionally, thermal-vacuum purification is also applied to remove gasses.

Removal of Mechanical Impurities.  Mechanical impurities, also known as particulate matter, can be removed after being subjected to centrifugal force.  Generally, not only mechanical impurities but also water is removed during this kind of purification that makes this method very widespread in industry.

Disadvantages of this method include:

•    purified oil product meets only 12-13 purity class; and
•    it is a labor intensive purification process.

Filtration is the method that has enjoyed a wide popularity in modern industry.  Based on the disposable filter, it ensures a high rate of purification, but needs to be replaced very often and may result in significant financial expenditures.  As an alternative, there are re-usable filters, though they will require regular cleaning. The acidity of oil may be reduced by applying adsorption purification.

GlobeCore  is an industry leader in manufacturing and supplying equipment for purification and regeneration of transformer, industrial, turbine, transmission and other types of oil products, including stove and diesel fuels.

GlobeCore’s equipment has been successfully operated in more than 70 countries of the world.  The fact that GlobeCore branded equipment successfully combines different methods of oil product purification shows it to have the best advantages that include:

•    high purification rate (10g/t –water, 0.1 % – gases);
•    simple design, high operational reliability and good endurance;
•  years of  trouble-free operation. The units can be operated both in automatic and semi-automatic modes to reduce the need of operator intervention;
•    Compact in size. All the units are mobile so that they are convenient to transport from one place to another; and
•    Eco-friendliness. The need to dispose of the exhausted Fuller’s Earth is reduced due to the Fuller’s earth regeneration mode that allows for Fuller’s earth reactivation directly in the equipment.

See more video about transformer oil purification

обновлено: June 24, 2016 автором: dannik