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Abstract on the topic of graduation work

Contens

Introduction

When assessing the role of organic additives in coal sintering processes, it should be borne in mind that it can be ambiguous, since, firstly, the properties of different organic additives can be very diverse, and secondly, coals of different degrees of metamorphism, to which various additives are also very different in sintering . In this case, one of the additives can enter into chemical interaction with the products of the primary destruction of coal and thereby fundamentally influence the processes of formation of the coal plastic mass, making it more or less fluid, reactive, and curable.

Organic additive affects the characteristic indicators of the formed coal plastic mass, but in the first case, its effect is deeper. It not only affects the plastic properties, but also makes a significant contribution to the formation of the molecular structure of the curable plastic mass, making it more or less graphitized . In the second case, the additive practically does not affect the molecular structure of the solid residue of thermal decomposition, but only increases or decreases its strength.In other words, the additive in this case plays the role of an additional quantity in the coal plastic mass. If it is enough, it can reduce the strength of the solid residue, and vice versa.

Coking is the most large-scale branch of thermal processing of coal. Coals must have a number of specific properties, among which the most important is sintering . An indispensable condition for the sintering of coal is their ability to go into a plastic state when heated. This property is more possessed by the most scarce coals of the middle stage of metamorphism.

Relevance of the topic

The limited possibility of using gas coals in blends of coke-chemical plants producing metallurgical coke is due to the fact that they, during layer coking, cause the formation of microcracks in coke, significantly reducing its strength, therefore gas coals are mainly used as energy and household fuel. In order to expand the raw material base of coking, new processes for the preparation and coking of charge materials with a high content of gas coals are being developed.

The purpose and objectives of the study, expected results

The purpose of this work is to assess the effect of anthracene additives, as one of the most important components of coal tar, on the formation of a plastic layer of gas coals according to thermocetrifugation. To achieve this goal, the following tasks will be solved: to evaluate the effect of anthracene on the yield of liquid nonvolatile products (GNP).

Object of study

The object of the study are fatty (F) and gas (D) coals.

Table one — Characteristics of the investigated coal
Charge Coal brand
layer		 Type of Technical analysis,  % Elemental analysis,  % daf
WaAdSdtVdafCHO+N
CentralG, k7а2,25,21,2236,085,15,118,71
ZasyadkoF, l4а1,42,61,0931,687,85,167,00
Experimental part

To evaluate the effect of the additive, comparative experiments were carried out to determine the yield ofthermofiltration products for low-caking Grade G coal and good sintering Grade J. coal .The main products of thermal centrifugation is the release of the GNP responsible for the sintering of coal.

In addition, the introduction of the additive increases the concentration of liquid-mobile non-volatile products in the system, which leads to an increase in the mobility, fluidity and thermal stability of the plastic mass. At the same time, the processes of formation of the mesophase are activated , hence, the processes of ordering the carbon structure of the semi-coke and coke.

Yield of Thermofiltration Products

Table 2 - Yield of Thermofiltration Products

As can be seen from table 2, as a result of co-pyrolysis of grade G coal with the addition of 5 and 10% anthracene, there is an increase in the yield of GNP up to 8-9%, respectively, compared with the release of GNP from individual coal.Consequently, the sintering capacity of coal increases. At the same time, the yield of the supernatant residue decreased by approximately 3–6%, and the output of the vapor – gas phase shows a tendency to increase . Consequently, the addition of anthracene increases the degree of decomposition of the supergrid residue.

Yield of thermofiltration products

Pic.5 – Yield of thermofiltration products

Picture 5 shows the histograms of the comparative yield of thermofiltration gas and fat coal with the use of 5 and 10%anthracene additive. As can be seen from the figure, for both coals there is an increased yield of GNP in the presence of anthracene and a decrease in the yield of the net residue. The positive effect of the additive, apparently , is related not only to the fact that anthracene oil is a good solvent for aromatics , but also to the fact that anthracene is a carrier of aromatic condensed structures that ensure the formation of an anisotropic liquid-crystalline phase.

Conclusions

  1. The work shows an increase in the yield of liquid non-volatile thermofiltration products. weakly coking coals in the presence of anthracene additives.
  2. The effect of the additive increases with an increase in its amount up to 10%.
  3. These data confirm the hypothesis that the low ability of gas coals to pass into a plastic state is explained by the insufficient content of aromatic hydrogen transmitters in their mobile phase.
  4. A comparative analysis of the effect of additives on low-caking gas and well-caking fat coals suggests that the highsintering capacity of fat coals is associated with the accumulation of a critical amount of polycyclic aromatic hydrocarbons that can be bound in mesophase.

References

  1. Грязнов Н.С. Пиролиз углей в процессе коксования// Н.С. Грязнов – М.: Металлургия, 1983. – 184 с.
  2. Глущенко И.М. Теоретические основы технологии горючих ископаемых: Учебник для вузов. М.: Металлургия, 1990, 296 с.
  3. Филоненко А.Я, Кауфман А.А. Теоретические основы коксования каменных углей// А.Я. Филоненко, А.А. Кауфман. – Липецк: Издательство Липецкого государственного технического университета, 2015. – 190 с.
  4. Neavel R.C., Larsen J.W., Wender J.//Coal Sciences. N.Y.: Acad. Press, 1982. P.1
  5. Larsen J.W., Wender J.// Fuel Process. Technol., 1988. Vol.20, N1, P.13.
  6. Marsh Y.P.L.Walker, Jr. Chemistry and Physics of Carbon. N.Y. Marcel Dekker, 1979, 15, p.230.
  7. Кисельков Д.М., Москалев И.В., Стрельников В.Н. Углеродные материалы на основе каменноугольного сырья / Вестник Пермского научного центра №2. 2013. – с. 13-22.
  8. ШПРМІ Д.М. Кисельков, Институт технической химии УрО РАН И.В. Москалев, Институт технической химии УрО РАН... В.Н. Стрельников, Институт технической химии УрО РАН
  9. Печень В.А., С.И. Федоренко, Бутузова, Л.Ф. Оптимизация условий термофильтрации жирного угля в присутствии добавки антрацена / Охрана окружающей среды и рациональное использование природных ресурсов: сборник докладов ХII Международной конференции аспирантов и студентов / ДОННТУ, ДонНТУ. – Донецк: ГОУ ВПУ «ДОННТУ», 2018. – с. 190-192.
  10. ГОСТ 17621–89 Угли каменные. Метод определения выхода жидкоподвижных продуктов из пластической массы угля. [Электронный ресурс]. — Режим доступа: GOST_1762189.