THE USE OF SULFUR AS A MODIFIER IN THE PRODUCTION OF SEROBITUM

ABSTRACT

The physicochemical properties of serobite have been studied. The composition of serobite has been analyzed. It has been established that bitumen contains (sulfur, oxygen, nitrogen). It has been established that the bitumen composition has a complex structure, and the properties of the serum have been studied. The effect of sulfur on bitumen was studied. The group composition of bitumen, its colloidal structure and rheological state have been studied. It has been established that bitumen binders differ in the flow rate at a certain temperature

АННОТАЦИЯ

Изучены физико-химические свойства серобита. Проанализирован состав серобита. Установлено что битум содержит (серу, кислород, азот). Установлено, что состав битума имеет сложную структуру, изучены свойства сыворотки. Изучалось влияние серы на битум. Изучен групповой состав битума, его коллоидная структура и реологическое состояние. Установлено что битумные вяжущие отличаются нормой текучести при определенной температуре.

Keywords: oil, road bitumen, sulfur, composition, modifier, hydrocarbon, asphalt, resin

Ключевые слова: нефть, дорожный битумов, серы, композиция, модификатор, углеводород, асфальт, смола.

Introduction. The relevance of the work lies in obtaining a product with physico-chemical properties, resistant to cracking, breakage, separation, allowing the production of road surfaces with a rare level of maintainability and high durability, resistant to frost. A promising direction for improving the quality of road bitumen is the use of sulfur to replace them

In the context of the modernization of highways, the use and production of petroleum bitumen will increase significantly in the coming years.In this case, the improved properties of the composition require an increase in the production of improved petroleum road bitumen, which can be achieved both by activating the production of existing bitumen and by improving the properties of petroleum bitumen with various additives and modifiers.

As the latest additive in world practice, more and more attention is being paid to the combination of cheap sulfur with petroleum bitumen, which opens up prospects for the development of sulfur-containing bituminous road binders and reducing bitumen consumption. The chemical composition of bitumen is very complex. Thus, they may contain mixtures of hydrocarbons of the methane and naphthenic series and their oxygen, sulfur and nitrogen derivatives. The elemental composition of bitumen ranges from: carbon -70...80%, hydrogen - 10...15%, sulfur - 2 ... 9%, oxygen – 1... 5%, nitrogen -0...2%. These elements are found in bitumen in the form of hydrocarbons and their compounds with sulfur, oxygen and nitrogen.

The solid part of bitumen – these are high-molecular hydrocarbons and their derivatives with a molecular weight of 1000...5000, a density of more than 1 g/cm³, united by the common name “asphaltenes”. Asphaltenes contain carbenes that are soluble only in CCl₄ and carbides that are insoluble in oils and volatile solvents. Asphaltenes are hard, brittle and non–melting particles black in color with a characteristic luster, having a strong coloring ability. They are a product of polymerization, condensation and dehydrogenation of aromatic naphthenic hydrocarbons, in particular, those included in resins. Asphaltenes are the most compacted part of bitumen and give them hardness and brittleness.

Resins - these are amorphous substances of dark brown color with a molecular weight of 500...1000, with a density of about 1 g/cm³. The density of resins depends on the content of hydrogen, carbon, oxygen and sulfur in them. The more carbon there is in relation to hydrogen, the higher the density of the resins. It usually ranges from 1.00 to 1.08 g/cm³, the sulfur and oxygen content reaches 10%. The resin content in bitumen increases its viscosity, hardness and elasticity.

Oils - a liquid part of bitumen at normal temperature, consisting of various hydrocarbons, with a molecular weight of 100...500, and a density of less than 1 g/cm³. They contain different amounts of aromatic, naphthenic and methane hydrocarbons in various bitumens [1].

To select the most optimal complex of oil refining processes, their modeling, substantiation of the capacity of oil refining plants, to develop ideas about the genesis of oil and solve problems of petroleum geology, it is necessary to know the chemical and fractional composition of oils [2].

Production of bitumen sulfur used in road construction. The method involves mixing molten bitumen, sulfur and an activating additive during heating. Amines in an amount of 0.3-3.0 wt are used to activate the reaction mixture.% relative to sulfur [4, 5].

Classical physical and mechanical characteristics

The traditional bitumen quality indicators used since the middle of the last century were determined for the selected bitumen bases and presented in the form of graphs in figures 1.

Figure 1. Values of the softening temperature and the penetration depth of the needle at 25 ° C of the initial bitumen bases

It follows from the data presented in figure 1 that the samples taken for research have a wide range of values both in terms of softening temperature (range of values from 37.5 to 56 °C) and in penetration at 25 °C (range of values from 35 to 182 · 0.1 mm). At the same time, even with the same softening temperature values, the spread of needle penetration values is up to 40-50 units, which indicates a fairly wide sample that provides good representativeness. Such a significant variation in values is explained by the fact that this graph summarizes data for all samples without dividing them by manufacturer. At the same time, as already mentioned, the quality of the resulting sample directly depends on the production conditions: the raw materials used, the production technology, the type of oxidation reactor, and the process parameters. The division of samples by region (Figure 1) allows us to take into account the raw material factor to a certain extent and see clearer dependencies of indicators consistent with the literature data [5, 6].

Bibliography:

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3. Patent V.B.Ivanov, T.S.Valiev, V.S.Kozlov Method of obtaining serobitum, 06/10/2012 Issue No. 16.
4. A.A. Andreev Forecasting the properties of SBS-modified bitumen binders depending on the quality of the bitumen base obtained at various refineries Dissertation Samara - 2022.
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