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INTRODUCTION

In the face of rising gas prices and problematic in the stability of its supply becomes relevant and promising predominant use in thermal power plants as the primary energy consumption of coal.

The use of solid fuels generates the problem of the reliable removal of slag and fly ash from the boiler ash collectors (usually from skubberov and ESPs).

Increase system reliability gidroshlakoudaleniya (Group Metering) in some cases may use air-lift units whose service, in most cases, superior turnaround time energobloka.Osnovnoy feature applications airlift units in the Group Metering systems of TPP is the continuity of the process of power generation and associated high demands on reliability.

Relevance of the topic

The experience of successful operation of airlifts in the coal industry was the basis for the expansion of their use in hydraulic systems, ash handling thermal power plants (TPP Group Metering) for solid fuel.

Work carried out the Donetsk Polytechnic Institute in cooperation with the All-Union Research Institute of Hydraulic Engineering. BE Vedeneyeva, the All-Union Institute of the heat engineering. FE Dzerzhinsky institutions "Teploelectroproekt" and "VNIPIenergoprom" to create systems with air-lift installations gidrozoloshlakoudaleniya confirm, in some cases, their advantages in comparison with traditional schemes with ground (dredging) pumps

The main advantages of airlifts in comparison with groundwater pumps in Group Metering TPP are: a) providing airlift for the full performance, is at least one year, the turnaround time unit (the turnaround time as a result of intensive abrasive wear of pumps 12GrT-8 in Reftinskaya, who used coal Ekibastuz, was 2.0 - 2.5 months); b) the location of electric power equipment above the floor boiler room that eliminates flooding in emergency situations; c) possibility of arranging airlifts in close proximity to sources of ash, which reduces the length of ash and slag channels flushing water flow and increases the consistency of the slurry removed; d) automatic matching supply airlift to the influx of slurry; d) a significant reduction in state service and maintenance personnel.

Installation of air-lift allow the implementation of two schemes of TES Group Metering: a) intrashop collection of ashes with the rise to a height of 10 - 12 m and transfer to the central nezaglublennuyu pumping station; b) the collection and disposal of ash and slag dumps on with lifting heights up to 30 - 35 m

Installation of air-lift used successfully in a number of large thermal power plants with an installed capacity of 4.0 MW and 6.0 at the actual coal ash is used up to 50% and the need to remove the hourly and 100 tons of ash from each working unit.

The main feature of the use of air-lift installations in TES Group Metering systems, in comparison with other areas of their use, is the continuity of the process of power generation and associated high demands on reliability.

The main part

When the hydraulic method of transportation of ash on ash disposal as a means of pumping groundwater are traditionally used (Dredge) pumps. However, the strong abrasive wear of the hydraulic pump, the need for deepening the installation below the floor boiler room, its weakening long ash and slag channels and a large proportion of industrial water consumption often reduces the effectiveness of the pumping station.

Increase system reliability gidrozoloshlakoudaleniya (Group Metering) in some cases may use air-lift units (Fig. 1), whose service, in most cases, superior turnaround time unit. Location of electric power equipment above the floor boiler room, the ability to organize airlifts in close proximity to sources of ash with reduced lengths of ash and slag channels and flushing water flow, increased consistency of the slurry removed, auto-negotiation lift gas-liquid flow with the influx and a significant decrease in state service and maintenance personnel often provides a tangible economic efficiency of air-lift units compared to traditional schemes.



Figure 1 - Schema airlift

Installation of air-lift allow the implementation of two schemes of TES Group Metering:

a) intrashop collection of ashes with the rise to a height of 10 - 12 m and transfer to the central pumping station nezaglublennuyu;

b) the collection and disposal of ash and slag dumps on with lifting heights up to 30 - 35 m

One of the most common methods for calculating the airlifts developed, based on the similarity theory [1-2]. The main similarity criterion adopted relative immersion mixer (H-height, h - geometrical immersion mixer), for determining the diameter of the riser pipe and D air flow QB and supply airlift Qe. The relative immersion mixer legitimately be regarded as the product of the Froude number and the Euler (as the characteristic linear dimension of a Froude number in the adopted length of the riser pipe H + h in contrast to the traditionally accepted in fluid mechanics, pipe diameter D).

The most widespread method of simulating the operation of airlifts Professor VG Geyer [1], the validity of which is confirmed by numerous effective working air lift installations in many industries. These calculations are based power balance liquid and gas flow in the lift with the highest relative velocity of the phases of 0.3 m / s. The basic equation, derived by Professor VG Geyer, is: where DB - diameter of the outlet end of the riser pipe.

Based on the relationships have been developed for the installation of air-lift several large thermal power plants with an installed capacity of 4.0 - 6.0 MW in actual coal ash is used up to 50% and the need to remove the hourly and 100 tons of ash from each working unit.

Conclusion

Thus, in some cases, removal of ash waste air lift installations is the preferred technical solution in terms of thermal power plants in comparison with the dredging pumps.

This paper will provide recommendations for the calculation and design of air-lift systems, ash handling plant TPP.

In writing this essay master's work is not yet complete. Final completion: December 2013. Full text of the work and materials on the topic can be obtained from the author or his manager after that date.

References

  1. V.G. Geyer Determination of the basic parameters of an air lift installation for pumping flooded mines / / Proc. articles for the 25th anniversary of the DII 1921 - 1946 GG - MASS: Ugletekhizdat. - 1946. - S. 79-92.
  2. Geyer V.G., V.S. Kostanda Hydraulic lifting pulp airlift and air-lift-uglesosno settings / / The mechanization and automation of production. - 1959. - № 9. - S. 52-56.
  3. Kostanda B.C. Experimental studies of the air-lift with variable ? and D in a pump shaft / / Proceedings of the DPI. Issue 12. - Volume 62. - 1961. - S. 103-113.
  4. Kostanda VS Calculation of air-lift units / / Proceedings of the DPI. Issue 12. - Volume 62 - 1961. - S. 93-101.
  5. Airlift Position: Textbook / VG Geyer, LN Kozyryatsky, VS Pascenco, JK Antonov - Donetsk: PDI, 1982. - 64 p.
  6. Encyclopedia of airlifts / FA Papayani, LN Kozyryatsky, VS Pascenco, AP Kononenko - M: Informsvyazizdat, 1995. - 592 p.