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Abstract

Content

Introduction

Our country is rich in reserves of solid fuels, which are a vital source of energy and chemical raw materials. The main method of coal processing is the coking with the further processing of products. Synthetic petrol, gaseous and liquid hydrocarbons can be obtained from coal by hydrogenation method [1].

Of all the processes of chemical processing of coal, the coking process received greatest development. This is due to the role and importance of the products of carbonization and mostly the coke that is used in the blast, foundry and ferroalloys production. Coke oven gas and other coking products are used as raw materials for chemical production.

The technology of coke production is constantly evolving and improving. Improvement of methods of coking charge preparation is carried out with the purpose of the economical use of a scarce and expensive well caking coals and the increase of content of scarce weakly caking in the charge. All coals with high ash content and high sulfur content are exposed to enrichment [2].

Theme relevance

One of the important indicators of the quality of mined coal is the content of total sulfur that is the most harmful component of coals. Increased sulfur content in coal reduces their quality, the deterioration of the quality of coke and increase of its consumption in the smelting of iron. The increase in the sulfur content of coal by 0,1 % leads to a decrease in productivity of the blast furnace and increase the coke consumption by 1,8 % [3].

Sulfur content in coal is one of the most important criteria of its suitability for coking, since coke quality indicators depend on the content of ash and sulfur.

However, the amount of reserves of coking coal with moderate sulfur content is rapidly reducing and soon will be almost exhausted.

Despite the huge importance of this issue, developed so far physico-chemical basis of caking coals does not apply to the coals of different genetic types of reductivity (GTR). This is due to insufficient knowledge of the mechanism of the transition of coals in to plastic state and the mechanism of interaction of separate components of the charge.

Goal and tasks of the research

The aim of this work is a comparative study of the extracts of fluid non-volatile products (FNP) of thermal filtration of coals G-Grade and F-Grade of different types by reductivity with the aim of identifying compounds that are responsible for the processes of caking; evaluation of the impact of the sulfur content of the coal on the yield, composition and properties of pyrolysis products.

To achieve this goal the following tasks will be solved:

  1. To separate and to study the components of the plastic mass of coal of different GTR and its their blends;
  2. To study the paramagnetic characteristics of coals of different types by reductivity, blends based on them and pyrolysis products;
  3. To conduct a systematic study of the composition of fluid non-volatile products (FNP) plastics to identify the components responsible for processes of caking.

Object of study

The objects of research its was coals of G-Grade and J-Grade of different genetic types by reductivity and their blends.

Table 1 — The characteristics of the studied coals
Mine Mark of coal
plast		 Type Technical analysis, % Elemental analysis, % daf
WaAdSdtVdafCHO+N
CentralG, k7a2,25,21,2236,085,15,118,71
DimitrovaG, l1b2,14,42,4938,783,85,349,50
ZasyadkoF, l4a1,42,61,0931,687,85,167,00
ZasyadkoF, k8b0,82,72,8131,787,35,237,20

The experimental part

The following standard methods of research are used in this study: thermal filtration (GOST 17621–89), technical (GOST 11014–89, 11022–95, 2059–95, 6382–91) and elemental (GOST 2408.1–95) analysis.

The separation of fluid non-volatile products on components was performed in the following way: the water was removed, then asphaltenes, carbenes, carboids were separated. The substance soluble in hexane was separated into a  base-carboxylic acidies, phenols, neutral oil by sequential treatment with 10 % H2SO4, 3 % NaHCO3, 5 % NaOH. The neutral oil was chromatographed on silica gel using as eluent hexane, benzene or acetone and subsequently recovered paraffinic-naphthenic, aromatic and polar hydrocarbons. In this work the aliphatic and aromatic fractions of neutral oils by the method of gas-chromatography-mass-spectrometry was stadied.

Table 2 — The characteristics of fluid non-volatile products of thermal filtration researched coals
CoalGaGbJaJb
N, spin/g x 10-17 in FNP 38,51,8114,9159,9
Exit and
composition of
FNP, %		 Exit of FNP 12,44 4,2821,3339,28
Absolute content
of components
in the neutral
oil of FNP, %		 Alkylated PAH 8,4011,9213,9520,14
Total PAH 10,2313,1215,5721,47
Alkylated benzene-fluorenyl,
fluorenyl (R = 1 ÷ 3)		 5,730,513,612,27
Total fluorenyls 6,710,573,61 2,27
Alkylated anthracenes +
phenanthrenes
(R = 1 ÷ 4)		 6,763,7216,7012,62
Total anthracenes + phenanthrenes 7,074,0718,8313,50

Conclusion

In this work the behaviour of coals of different genetic types of reductivity and their blends under conditions of centrifugal thermal filtration was stadied, that enables one to separate and detailed of fluid non-volatile products (FNP).

There was established an existance of link between the output of fluid non-volatile products, content of paramagnetic centers (PMC) and the composition of neutral oils, the separation from extracts fluid non-volatile products.

References

  1. Глущенко И. М. Теоретические основы технологии горючих ископаемых: Учебник для вузов. — М.: Металлургия,1990. — 296 с.
  2. Эйдельман Е. Я. Основы технологии коксования углей. — К.; Донецк: Вища. шк. Головное. изд-во, 1985. — 191 с.
  3. Горная энциклопедия.— М.: Советская энциклопедия, 1987. —  Т. 3. — 592 c.
  4. Маковский Р. В. Основы включения в состав шихт для коксования разновосстановленных углей и их смесей. — Рукопись. Диссертация на соискание ученой степени кандидата технических наук по специальности  05.17.07 — химическая технология топлива и горюче-смазочных материалов. — ГП УХИН, Харьков, 2014.
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