Tag Archives: Waste Oil

Waste Oil Reclamation Technologies

Solutions,

The article analyses existing approaches to transformer oil reclamation. It considers acid and alkaline cleaning, vacuum distillation, rectification.  It specifies the advantages and disadvantages of each method.

In recent decades, mankind has been facing  a threat of ecological catastrophe, This forces to revise  procedures dealing with industrial waste, especially waste oil, an attitude of which also changed.  A recommended measure for waste oil is – reclamation – restoration of its operation properties  and reuse for its intended purpose.

Different methods are used for oil reclamation. When choosing a restoration technology, it is important to consider waste oil characteristics.  In some cases only physical method is enough  to achieve a good result. In other cases a sequence of processes is needed.

Oil collection and   reclamation should be carried out separately, or in groups.  The final product is not constant and is defined by the depth of purification and the selected reclamation technology.

Oil reclamation is removal of contaminants or separation of undesirable components: usually including emulsified water, light combustible products, and other mechanical admixtures.  Valuable hydrocarbon makes up at least 70-80 % of waste feedstock, low-boiling fractions make up 10.5 % and resinous substances  10-20 %.

Some purification processes are based on the interaction of undesirable components with chemical reagents.  These processes include acid cleaning,  especially in industrial practice.

Acid cleaning is mainly used to remove:

  • asphalt-resinous substances;
  • oxidized products;
  • unsaturated hydrocarbons;
  • compounds containing sulfur and nitrogen;
  • aromatic compounds.

In most cases, 92-96 % sulfuric acid is used for purification.  Its consumption is different for each case, and should be determined experimentally.  Optimal flow temperature is also found by tests and in most cases is 35-80 °C.

Result of this purification is acid sludge  Its disposal requires additional high costs.  This is one of the main drawbacks of this method.

Alkali cleaning can be used as an autonomous process, or in combination with sulfuric acid cleaning.  It removes the following substances:

  • organic acids;
  • sulfur-containing compounds;
  • phenols.

In most cases, 2-15 % water solutions of sodium hydroxide are used.  Its required amount is also determined experimentally and ranges from 2 to 15 %.  The degree of purification depends on the flow temperature, so the neutralization is carried out at 70-90 °C.

Alkali contacts with oil for 5-10 min.  It is necessary to stir it during the process.

Wastes resulting from alkali cleaning, may be used in the production of naphthenic soap and emulsifiers.

Fractional distillation and rectification under vacuum are also known as purification methods.  Distillation is separation of hydrocarbons of various molecular weight.  Vacuum distillation and rectification are splitting waste oil into fractions of different viscosity.

When choosing a particular type of waste oil reclamation, it is necessary to consider the results of preliminary studies, that allow to calculate the approximate quality of the product.

Waste Oil Recycling

Solutions,

Virtually any production is accompanied by large amounts of waste which can be reused after undergoing appropriate treatment.  It is  predicted that in the future, the new raw materials will be recycled from industrial waste.

Used lubricant oil (ULO) is liquid waste product.  ULO is any oil derived from crude oil or synthetic oil, contaminated with physical or chemical impurities as a result of its exploitation.  Even in normal operation there is ingress of dirt, metal particles, water, or chemicals into lubricant oil.  Over time the quantity of impurities exceed the limit  making the use of lubricant impossible.

To date, the environmental safety  is an important factor when it comes to disposal of waste lubricants, as they have a negative impact on our atmosphere, soil and water.  For example, water pollution with waste lubricants amounts to about 20% of total technogenic pollution, or 60% of total pollution with oil products.

There is no doubt in the  need for competent recycling of waste oils.  Burial or destruction by burning, firstly, is quite expensive, and, secondly, in many cases it gives rise to even greater environmental problems.

Environmentally safe  is processing of waste lubricant oil in order to obtain a variety of commercial products (lubricating grease, fuel, oil, preservation material, etc.).

In the scientific literature the terms “purification”, “regeneration” and “recycling” are most often used in the context of lubricant oil recovery.  Let’s try to clearly define the purpose and field of application of these processes.

Purification is continuous or periodic oil treatment using cleaning equipment (settling tanks, filters, centrifuges or adsorbers).  Implementation of such  treatment does not always obtain a product which would have the same performance indicators as fresh oil.  But this is not always required.  Timely treatment extends oil service life.

Purification of utilized oil , not draining it from the equipment, can be carried out only with circulating lubrication system for industrial, turbine, motor and virtually all types of transformer oils.

Regeneration is restoration of waste oil quality to a level of fresh oil.  Regeneration provides the ability to reuse the processed product for its intended purpose.  The technical realization of this process, in contrast to purification, requires the use of more complex operations involving coagulation, sulfuric acid purification, and adsorption purification. In many cases, regeneration is carried out directly at the site where lubricating oil is consumed.

Waste oil recycling is carried out in three directions:

  • recycling of mixes with negligible synthetic oil impurities;
  • separate, by brands regeneration – obtaining corresponding products;
  • recycled waste for boiler or furnace fuel.

With the right approach, the use of regenerative technologies recovers oil, which costs 40-70% less than almost the same amount of fresh oil.