Petroleum oil is widely used in modern industry. The smooth operation of engines and their fuel consumption largely depend on the quality of oil.
Selective solvent refining is the basic process of petroleum oil production. It consists in dissolving the unwanted components with no impact on the compounds that should be preserved.
In practical terms, to carry out such purification, the solvents should meet the following requirements:
- strong selective solubility within a wide range of temperatures;
- difference between the densities of solvent and raw material;
- the boiling temperature of the solvent should be lower than the boiling temperature of raw material; and
- low heat of evaporation.
The following is the list of the benefits of the selective purification:
(1) improves the stability and viscosity-temperature properties of petroleum oils; and
(2) reduces the risk of carbon formation and oxidation.
There have been increased requirements for the qualitative characteristics of oil because of the constant improvement of the equipment that uses oil. It is therefore, necessary to find new ways to improve selective purification.
Nowadays there exist three ways to improve the process performance indexes:
(1) Improvement of the technology;
(2) Application of effective solvents; and
(3) Upgrading of technological equipment.
The type of the solvent applied is of great importance since it influences future technical and economic indexes. Phenol and furfural are considered to be the most widespread solvents.
The solvent power of phenol is better than that of furfural and it is used to obtain high-quality oils from low-quality raw material.
Phenol however, has the following disadvantages:
(1) low selective ability (in comparison with furfural);
(2) stable emulsion formation during extraction process; and
(3) high toxicity.
When applying furfural, the solvent is supplied to the top of the extraction column, which was previously warmed up to a temperature of 110°C and 120°C. The oil distillate that has been heated up to between 65°C and 75°C is supplied to the bottom of the unit. Because of the different densities, furfural and oil are moving opposite each other. The oil distillate is cleaned while passing through the column and exiting through its top part. Having absorbed the unwanted substances, furfural is drained at the bottom of the unit. The high toxicity of the solvent is the main disadvantage of this method. There have been therefore, many attempts to find a revolutionary new solvent with no impact on the oil.
Many scientific publications consider N-methyl pyrrolidone to be today’s most promising substance to replace furfral. In particular, special attention is paid to its performance characteristics such as (1) high solvent ability; (2) selectivity; (3) hydrolytic and thermal stability; (4) low corrosivity; and (5) low-toxicity of N-methyl pyrrolidone.
Nowadays, the units of selective oil refining, based on N-methyl pyrrolidone have been successfully operated in the USA and Russia. It is also well established that “solvent pairs” may be also applied to obtain residual oils. In such cases, the purification process combines two procedures such as:
(1) propane deasphalting (PDA); and
(2) selective treatment by phenol mixture and cresols.
Often this process is called the “duosol process” and has been widely applied in many countries. It is considered highly feasible to apply selective purification at oil refineries that usually deal with huge volumes of oil products. And what about small facilities that have used oil accumulated in their storage tanks? Such factors as unprofitable selective purification and the need to purchase a new petroleum product as well as the search for new ways to dispose of the old oil suggest that a new optimal solution should be found.
GlobeCore is an industry leader in manufacturing and supplying equipment for filtration, degasification and regeneration of transformer, turbine and other types of industrial oils.
GlobeCore’s technologies distinguish themselves through eco-friendliness and cost-effectiveness.
GlobeCore has developed and supplied different machines to meet our customer’s orders and needs as follows:
(1) units for separate procedures such as filtration, degasification and dehydration; and
(2) units for complex regeneration to restore all performance characteristics of oil (breakdown voltage, tangent delta, acid number, color, and other important operational parameters.)
Due to its mobility, GlobeCore’s equipment may be operated directly at all remote operating sites. Oil regeneration units are easy to use and all the technological processes are automated. The autmoation allows for significant cost reduction and trouble-free operation.