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Introduction

Industry for the production of cement contributes to the worldwide СО2 emissions caused by human factors, in the amount of 5%. This determines the need for measures to reduce greenhouse gas emissions into the environment. In addition, the production of cement is associated with the release of a huge volume of aerosols and contaminated wastewater.

With significant reserves of mineral resources, located close to the surface, a developed industrial base in most enterprises of the cement industry used the open method of mining. It is the most promising technological and economic relations. However, at the Ukrainian and foreign companies is insufficient level of environmental protection and resource-saving technologies. Remaining after the seizure of raw materials, such as chalk or marl, developed space is a moon lifeless landscape deprived of fertile soil layer with depressions prone to erosion damage boards. Spontaneous recovery of flora and fauna in these areas takes hundreds of years, and sometimes is impossible.

Necessary technology intensive rehabilitation, and possibly improve, compared with the initial state of biodiversity in the remaining after mineral extraction areas. On the other hand, the technology must meet the requirements of low cost and, if possible, at least a partial payback [1].

1 Theme urgency

Research to establish the parameters of heat exchange in the rock mass aqueous medium of bio facilities in order to increase the efficiency of the extraction of geothermal energy and improvement of this technology – based restoration of biological diversity in the goaf quarries is an actual scientific technical problem.

2 The purpose, the idea of work and objectives of the research

2.1 Goal of the research

The aim is to select and study the parameters of technology of restoration of biological diversity in the goaf quarries based on the disclosure laws of heat exchange between the rock mass and the aquatic environment by using geothermal heat exchangers in the construction of bio.

2.2 Objectives work

To achieve this goal required the following tasks:

  1. Review existing technology restoration of biological diversity in the goaf of quarries.
  2. Carry out theoretical studies of patterns of change in the heat transfer in the rock mass-water environment in the construction of bio.
  3. Carry out pilot studies increase the thermal conductivity of the rock mass.
  4. Select and justify the technology parameters restoration of biological diversity in the goaf pits using geothermal energy.
  5. Run ecological and economic evaluation of the proposed method of using geothermal energy for the restoration of biological diversity in the goaf pits using geothermal energy.

2.3 Idea of working

The idea of work is to provide the optimum temperature to aquatic life activity of bio construction through the use of geothermal energy.

Object of research: low-grade geothermal energy distributed in the rock mass.

Subject of research: thermodynamic processes and conditions governing the transfer of heat in the rock mass – aqueous medium in the construction of bio.

3 Description of the method

To accelerate the process of formation in the goaf biogeocoenose quarries can only create the necessary hydrogeological conditions. Water is the basis for the formation and development of living forms of matter. The authors propose a way to accelerate the recovery of biodiversity in the goaf pits by cleaning the atmosphere and hydrosphere, the revival of flora and fauna on the basis of year-round state control flows pit water through the use of geothermal energy.

The main inflow of water into the quarry comes from the aquifer, which is shown from the left edge of the pit (Figure 1). Gob is schematically represented in the form of a rectangle. At the heart of the developed space is the main dam, built of reinforced concrete or bulk, of not prone to soaking materials such as pieces of sandstone, limestone, used car ramps, construction or other wastes fourth grade.

The main function of the dam – the bottom of the career divided to give the circular motion of the water flow, thereby increasing the distance of the flow of water and ensuring the duration of its physical and biological treatment. To increase the length of the passage of water through the mined-out space, thereby increasing the purity of water, created by the auxiliary dam separating the top and bottom of the quarry. Auxiliary dam staggered. At the location provided for the formation of dams marshy environment with abundant vegetation. The basis of the dam will serve as concrete blocks or rocky mounds of not prone to soaking rocks, overlain by a layer of black soil. To minimize erosion and leaching of the soil surface dams populated by plants.

For year round water purification streamed right and left auxiliary dam proposed drill hole depth of 50–100 m, placing them in a vertical borehole heat exchanger collector type nestable. Water from the aquifer through confuser enters the annulus and by the velocity head moves down the pipe. As we move heat exchange occurs between the wall of the metal pipe with the temperature surrounding rocks, and a water stream, causing the water temperature becomes close to the temperature of surrounding rock Donbass component under conditions of 12–15 °C. At the bottom of the flow tube due to the dynamic pressure, it changes direction by 180 and lying on the inner plastic pipe to the surface.

As a result, during the cold season water will be heated by geothermal energy and hot to cool. The water is heated to the required temperature to maintain this temperature throughout the year will create favorable conditions for the life aquatic year round [2].

Diagram of the construction of water treatment career for using geothermal energy

Figure 1 – Diagram of the construction of water treatment career for using geothermal energy: 1 – main dam; 2 – additional dams; 3 – settler No. 1; 4 – channel; 5 – primary settling tank; 6 – pump; 7 – a pipe to pump water; 8 – entry polyunsaturates; 9 – water production; 10 – aboard a career; 11 – vertical wells collector pipe in pipe; 12 – well filled with heat conducting compound (Animation: 5 frames, 6 cycles of repeating, 158 kilobytes)

Conclusion

To avoid reducing the effectiveness of water purification in the winter, it is necessary to maintain the temperature of water in water treatment at 10 °C–12 °C. In this temperature range water is not warm and the temperature drop significantly under the ice crust structure. At a temperature of wastewater below 6 °C the activity of microorganisms and hence, their activity sharply reduced; at temperatures above 37 °C significantly reduced nitrification rate due to reduction of dissolved oxygen in the water. Thus, the optimum temperature is 10 °C–12 °C in winter and 28 °C in summer [3].

Maintaining the required water temperature all year bioochistitele will:

  1. Create favourable conditions for the life aquatic year round.
  2. Prevent freezing of shallow streams and destruction of algae and shellfish in the winter.
  3. During the summer, by cooling the water in the shallow part of the pit and improve living conditions for aquatic organisms.
  4. Contained in the resource water treatment plant will perform the function of cleaning the atmosphere all year round by dissolving carbon dioxide and other gases with subsequent assimilation by plants for buildings and power cells.
  5. Use ice-pond as a place for wintering waterfowl [4].

To ensure water geothermal heat exchanger and heat was produced hydraulic calculation.

According to our calculations, for water heating by geothermal energy to a temperature of 12 °C geothermal wells to be drilled with a diameter of 200 mm and a length of 76 m, which is at a depth of 25 meters must be equipped with thermal insulation foam glass thickness of 20 mm, and then install steel casing of steel 4H13 with a wall thickness of 20 mm, and coaxial with it a plastic tube with a diameter of 50 mm and a length of 75 m.

The space between the casing and the array in the area from 25 to 75 m clay-graphite filled with a mixture of 50% graphite content.

When the daily consumption of water in the quarry 660 m3/day, it is necessary to drill 24 such wells.

Due to technical difficulties and high costs in the organization of the water supply pump in the well, it was decided to work in the mode of its gravity. For this purpose at the inlet of the annular gap is necessary velocity head, allowing the heated water to overcome the frictional losses and local resistance and out of the inner tube on the aquifer.

According to the calculation for the movement of water by gravity pit must be designed with a slope of 6,5°.

Thus, the use of vertical borehole collector nestable and use clay-graphite mixture when it is placed in the ground for the intensification of the process of extraction of geothermal energy would stabilize the temperature regime of pit water and provide year round work of bio structures [5].

References

  1. Костенко В. К. Использование геотермальной энергии для повышения эффективности биоочистки сточных вод цементного предприятия. / В. К. Костенко, Е. Л. Завьялова, О. П. Чепак Проблемы недропользования: междунар. форум-конкурс молодых ученых, 22–24 апреля 2015 г.: сборник науч. тр. Часть ІІ. – Санкт-Петербург, 2015. – С. 32–35.
  2. Костенко В. К. Восстановление биологического разнообразия в выработанных пространствах карьеров. / В. К. Костенко, Е. Л. Завьялова, О. П. Чепак Проблемы недропользования: междунар. форум-конкурс молодых ученых, 23–25 апреля 2014 г.: сборник науч. тр. Часть ІІ. – Санкт-Петербург, 2014. – C. 131–133.
  3. Завьялова Е. Л. Определение параметров технологии восстановления биологического разнообразия в выработанном пространстве карьеров. / Е. Л. Завьялова, О. П. Чепак Екологічні проблеми топливно-енергетичного комплексу: VI регіональна наук. конф. аспірантів і студентів, 14–15 травня 2015 р: зб. матер. конф. – Донецьк: ДонНТУ, 201. – С.34–38.
  4. Национальный доклад Украины о гармонизации жизнедеятельности общества в окружающей природной среде: Специальное издание к V Общеевропейской конференции министров окружающей среды Окружающая среда для Европы. – Киев, 2003.
  5. Костенко В. К. Повышение экологической безопасности шахтной природно-промышленной экосистемы за счет использования геотермальной энергии. / В. К. Костенко, С. Салехирадж, Е. Л. Завьялова Труды второго международного научно-практического семинара Повховские научные чтения / Под общ. ред. Ступина А. Б. – Донецк: ДонНУ, 2012. – С. 174–181.