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Abstract

This master's work is not completed yet. Final completion: January 2015. Full text of the work and materials on the topic can be obtained from the author or his adviser after that date.

CONTENTS

INTRODUCTION

Growth of world oil prices led to increased interest in coal as a priority coolant and raw materials in the chemical and other industries. The concept of development of coal industry of Ukraine (2008) provides for an increase in production by 27% (96.5 million tons) by 2015. However, for the transmission of large amounts of coal at a considerable distance the most profitable is hydrotransportation.

1. TOPICALITY

Relevance of the work due to the importance of research and development of technologies for the preparation of coking coal to the main hydraulic transportation. Main hydrotransportation system (MGTS) have some fundamental advantages over traditional transmission technologies of coal over long distances, and therefore are promising at distances from a few hundreds to 1-2 thousand miles. At the same time, as shown by previous studies, coking coal during transmission over long distances hydrotransport partially loses its coking properties. A number of scientific research organizations, in particular NGOs Haymek (Donetsk) and DONNTU in 1990-200 years developed a framework of alternative technologies that allow partially mitigate the negative impact of factors hydrotransport for coking coal properties. But these technologies should be further improved with the use of machinery and mineral processing technologies.

So the research problem, the technology of preparation of coking coal to the main hydraulic transport require further research and development of domestic science. This determines appropriateness for choosing this theme of master's work.

2. PURPOSE AND RESEARCH PROBLEMS

The purpose of this work is research and improve the technology of preparation of coking coal hydrotransport transmitted over long distances (200-500 km or more). For this purpose the alignment process hydrotransportation and partial oil agglomeration to develop a new high-performance technology for the ultimate in industrial hydro-systems.

3. REVIEW AND ANALYSIS TECHNOLOGIES FOR THE PREPARATION OF COKING COAL TO THE MAIN HYDROTRANSPORT

3.1. Magistralny hydraulic transport of coal

Figure 1 - Diagram Animated work diagram pipeline hydrotransport system (volume of 30 kb, 8 frames, delay bBetween frames 1 s)

Figure 1 - Diagram Animated work diagram pipeline hydrotransport system (volume of 208 kb, 9 frames, delay between frames 1 s)

Hydrotransport pipeline system consists of three main terminals (Fig. 1): preparatory, the linear part of the pumps and receiver.

Main characteristics of large hydro-systems are given in Table 1. The table shows that the length of working pipelines reaches 480 km, and the maximum size of the piece of material does not exceed 3 mm. The most well-known system of the last century was the system of Black Mesa - Moheyv, closed due to water supply problems [1]. Last newest project pipeline design and Wuhan Science - Research Institute of Coal Technology [2] called "Sheng- Wei". Its capacity of 10.00 million tons/h , pipe length - 729 km [3].

Table 1 - Main characteristics of modern pipeline system

System Length, km Diameter, mm Productivity per year (Mt / year) Quantity of pumping stations Level of implementation
Kadic - East Lake (United States, Ohio) 174 254 1,3 4 Canned. Worked in 1957-1963
Black Mesa - Moheyv (USA, Arizona) 440 457 4,4 3 Canned. Worked in 1970-2006
Belovo - Novosibirsk (Russia) 252 500 3 3 Canned. Worked in 1990-1994
Freiling - Emil (France) 9 386 2,5 – 3,0 – Has been in operation since 1952
Porto Torres (Italy) 4 406 3,5 – 4,1 – Is in operation
Sheng - Wei (China) 729 559-610 10 6 Is in operation

3.2. Factors influencing hydrotransport for coking coal properties

Deterioration of coking coal properties in hydraulic transportation various authors associated with various technological factors. Hydrodynamic impact of turbulent flows in the pipeline, as well as mechanical shock at the pumps, fittings, on the road hydrotransport systems lead to mechanochemical destruction of the coal particles with a break chemical bonds and the formation of new interfaces coal - water [4]. The most likely break in the side chains to form a coal substance of free radicals having a high reactivity, including with respect to the dispersion medium (water). Furthermore, prolonged contact with water is obviously a hydrolytic degradation of coal. Transition phenomena observed in the aqueous phase of humic acids [4,5]. Most researchers point to a negative role is a factor in hydrotransport material grinding system. V.Korshunov found that the transition of the coal in the class of 0.5 mm alters temperature zones thermochemical processes coking, and this affects the coke strength [6].

Besides crushing at hydrotransportation detected redistribution effect on petrographic micro size classes [7]. In particular, there is a significant part of the charge overgrinding vitrinite to the size of 10 microns or less. In this case mainly overgrinding grade coal vitrinite G. Its content in small classes increased from the initial charge twice.

Yu.Get relates the change in the properties of coking coal from the change in the form of carbon grains in the pipeline - their agglomeration [8]. Figure 2 shows the effect of agglomeration grain, Ukrainian scientists found in the study of hydraulic transport on the stand of the "torus".

Figure 2 - Change the shape of the grains F grade coal during hydraulic transportation to a distance of 450 km :1-15 mm; 2-12 mm; 3-10 mm; 4-5 mm; 5-2,5 mm.

Figure 2 - Change the shape of the grains F grade coal during hydraulic transportation to a distance of 450 km :1-15 mm; 2-12 mm; 3-10 mm; 4-5 mm; 5-2,5 mm.

G.Rigbi explains the deterioration of coking coal properties enswathing coal grain clays that in his opinion, increases the fragility of coke [9]. Regarding the effects associated with the influence of clay, another phenomenon was observed - the clay material was washed out with the primary substance and coal coal grains enveloped in particular thin, totally or partially, by excluding them from the sintering process (at the contact surface with the clay).

V.Erdman, R. Kelling and D.Lyayninger believe that the deterioration of coking coal during hydraulic transportation stipulated by its oxidation [10].

3.3. Modern technology hydrotransport coking coal

In Ukraine, a unique technology for long-range transportation of coking coal was developed by the Donetsk National Technical University and the NGO Haymek [11].

In technology Haymek says that the group slurries with properties conditionally - homogeneous media may also include fine-grained coal with a maximum particle size of 2-3 mm and a certain content of fine (micron) particles [12].

Technology of Donetsk National Technical University (DonNTU) provides partial oil granulation coal slurry that allows, first, significantly improve its mechanical dewatering at the receiving station, and secondly, provides enveloping coal grain oil film that significantly reduces (or eliminates) oxidation of coal surface and enveloping her sodden clay during transportation, thirdly, causes the formation of structures such as the center - shell radically reduce coal grinding grains at gidrotransprtuvanii [13].

REFERENCES

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  13. Промышленный транспорт 6 // Издательство "Транспорт"–Москва,1984 г.