Disposal of lubricating liquids by one species of oil and oil-containing waste are spent lubricating and cooling fluids (coolant) formed in technological processes

Disposal of lubricant-cooling liquids

One of the types of oil and oil-containing waste are exhaust coolant (coolant), which are generated in the technological processes of repair shops of enterprises of locomotive, carriage, travel and other farms, as well as at the railway industry factories. Russia finds the use of more than 50 kinds of coolant, which contain various (in structure and viscosity) mineral oils with additives of synthetic esters, plant and animal oils, emulsifiers, alcohols, bactericides and high molecular weight adhesives. As the physico-chemical properties of the coolant change. If in freshly prepared coolant, the content of petroleum products is 25-55 g / dm 3, then, as they use, their concentration is growing due to oil saturation from hydraulic systems of machines, and in exhaust coolant it reaches 90 g / dm 3. In the high temperature zone when cutting metal, organic compounds are oxidized, microorganisms and dust fall out of the air, and it becomes a nutrient medium for microorganisms and is gradually saturated with dead biomass. In the exhaust coolant there are many chemicals hazardous to the environment, as well as heavy metals.

Thousands of tons of exhaust coolant are accumulated annually on large engineering enterprises, since the service life of even resistant coolant type "Velle" does not exceed 10-12 months. Exhaust coolant is an oil emulsions in water, for the destruction of which is used centrifugation, reagent coagulation, evaporation, combustion or combination of these methods.

Almost all technologies for coolant are not sufficiently effective. This is due to the resistance of emulsion, large quantities and variety of chemical compounds and mechanical impurities contained in them.

Centrifugation allows you to extract suspended substances, biomass and limiting hydrocarbons from spent reserved. This method can only be used as the first (preliminary) level of coolant treatment of petroleum products.

Preliminary coagulation increases the effectiveness of centrifugation, but does not allow to extract the main mass of petroleum products and microorganisms. In the process of centrifuging at high speed (separation factor – at least 7250), the colloidal system is destroyed, and oil having a smaller density than water is distinguished from the dispersed medium. To facilitate the destruction of the emulsion, acid is added to it in such quantities so that the pH of the medium amounted to 1-2.

Reagent coagulation is to add to the emulsion of sulfate aluminum, chlorine or sulfate iron in combination

Rice. 5.4. Flotation installation diagram for coolant destruction:

• 1 — sump; 2 – separator; 3 – Receiver; 4 – flotator; 5 – Capacity with coagulant; 6 — chasball; 7 – Foam Collection; 8 – Collection of oil; 9—12 – Dispensers of coagulants; 13 — pH meter; 14 – compressed air;
• 15 – Pump of Tania with lime milk or caustic. The resulting precipitate after settling is removed and is disposed of. The main part of petroleum products and suspension with the introduction of coagulants is deposited on the bottom. However, the speed of their deposition is very small, and the precipitated hydroxides of metals and petroleum products are very difficult to dehydrated.

Evaporation Exhaust coolant, and the formed concentrate is difficult to dispose. Also energyless Ozonation, a disinfection Coolant can be achieved by less expensive reagents.

The most effective methods of coolant destruction are Reagent flotation and heat treatment. During flotation, petroleum products are extracted, weakly associated with water. Physically and chemically associated with water oil products and microorganisms from sustainable coolant is very difficult to extract.

The schematic diagram of the flotation unit for continuous destruction of the exhaust coolant is shown in Fig. 5.4. The main part of the oil (85-90%) is separated in the centrifugal separator 2. The oil obtained after the separator can be used as a fuel or for the preparation of new emulsions. Deeper emulsion cleaning occurs in the flotator 4.