to create high-quality and reliable road surface are different in composition and properties of materials.One is tar.What is this stuff, what properties it has, and where applicable, is very well known in the first place builders and road workers.People of the older generation, who grew up in the Soviet Union, will remember what was their first chewing gum - tar.Outwardly, this resinous substance formed after processing oil having a viscous structure and a pronounced black.Tar yield is 8 to 45 percent by weight of the oil.
Tar - what is it
basis of this material are oil products, so the composition of tar is very similar to petroleum fractions.The required components are:
- Petroleum resins, consisting of complex composition of hydrocarbons and tar imparting strength and ductility.
- asphalt - solids that increase the thermal stability.
- Asphalt acids and their anhydrides, having the consistency of a resinous polinaftenovym and related acids.
- also a necessary component of tar is the high content of metal impurities present in the oil.
Properties tar
They depend mainly on the properties of the oil, as well as technologies used in its processing.Nature petroleum fractions affected and some tar characteristics such as density, melting point and flash coking.A better tar obtained from heavy oil and resin is about 8% of its weight.
Application tar
in a variety of industries use tar.What is an essential component for the manufacture of road and construction bitumen, known, perhaps, everything.But in addition, tar is required in the manufacture of motor fuel, fuel oil and combustible gases.In the construction industry and the rubber industry is used as a softener.Tars are high in resins can be processed into diesel fuel using the method of hydrogenation and cracking.
In order to remove the resin-asphaltene components and polycyclic hydrocarbons that have low viscosity and high carbon residue, tar deasphalting is used.The solvent usually is propane.But along with it when it is required to receive the feedstock hydrocracking or catalytic cracking can be used pentane and butane.Sometimes carried out a two-stage deasphalting, when obtained in the first stage of the asphalt allocates more viscous component - DAO 2.
At roadworks tar is brought in solid form, and have immediately prior to use it is heated to a liquid state.
Secondary resources
In the production of detergents, light oils, waxes and other purification processes where the reagent is used sulfuric acid by-product is formed, which is called acid sludge.This is a valuable resource in the secondary form black gummy mass containing mainly sulfuric acid and organic compounds.Ton acid sludge allows to obtain 600 kg of fuel oil, 230 kg gypsum 110 kg 60 kg coke or gaseous hydrocarbons.
danger of acid tars for environmental
Despite its value as a raw material for asphalt binders, and even one of the most significant factors that threaten the environment, is the acid sludge.What is this stuff really is a source of danger to the flora and fauna, it is easy to imagine, if you remember its composition - resinous substance and a free sulfuric acid content of which can be up to 70% of the total weight.The danger is
and storage of acid tars.Due to the fact that today there are no rational methods of disposal, the waste is simply dumped in ponds, sometimes occupying a fairly large area.As a result of redox processes that occur spontaneously on the surface of the storage facilities, a large amount of sulfur dioxide.After heavy rains or melting snow in the spring of acidic water flowing out of the overcrowded ponds, acidifying the soil and groundwater.
All this adversely affects the ecological situation near the location of these ponds, adversely affects the health of people living in the surrounding area.Millions of tons of acid tars warehoused in open ponds on the territory of Russia.Almost all refineries have such waste.In only one of the Nizhny Novgorod region has accumulated more than 250 tons.
Waste Disposal
the modern development of the construction of growing demand for products such as bitumen, tar, bitumen mastic asphalt.Accordingly, it increases the number of producers.Many of them try to solve the problem of waste acid tars, using the method of sulfuric acid cleaning, but it is still insufficient in scale, t. To. This is quite a complicated process.It requires expensive acid-resistant materials, the development of special techniques and storage conditions.Today, we developed the most effective technologies for waste acid sludge.
Almost all professionals involved in road construction, tar is rightly considered a unique material.His remelting allows you to create different compounds that have been successfully used in road construction.And the use of tar in roofing and construction work, for fuel oil, lubricating oil and fuel oil further enhances its value.
