ANALYSIS OF METHODS FOR INCREASING THE OPERATING TERM OF THE BOILER UNIT TP-100A OF THE POWER UNIT № 10 BURSHTYN TPP

Abstract

Boiler units with a view to prolonging their work are being reconstructed and modernized by carrying out qualitative repair works, replacement and restoration of worn out and spent resources of the most responsible units and parts of the units themselves and associated pipelines. When choosing a reconstruction project, it is important to consider the possibility of placing new equipment within the existing boiler units, minimizing the cost of the reconstruction with the achievement of maximum effect, the possibility of performing works for reconstruction and subsequent maintenance. Consequently, methods of increasing the life of the boiler unit, increasing its efficiency and maneuverability characteristics are extremely relevant. Therefore, we have stated the requirements for maneuverability. The power unit should be designed to work in a maneuverable mode that is to participate in primary and secondary regulation of frequency and power under normal and emergency modes of operation of the electric power system of Ukraine. When working on boiler plants, an adjustment range for loading, minimum and maximum permissible load should be provided. The lower boundary of the adjustment range of the load of the power unit shall be established, proceeding from the conditions of maintaining the unchanged composition of the operating equipment and the reliability of the boiler screen system and the operation of the automatic control system in all specified load ranges without personnel interference. The boiler must operate in the range of load of 50–100 % of nominal without the use of fuel for stabilizing combustion (gas, fuel oil). Expansion of the lower limit of the operating range of the control of the load of the power unit up to 50 % at the combustion of solid fuel without the use of backlighting fuel and providing a liquid slag removal taking into account the expected maneuvering mode of the power unit at the nominal boiler pressure, without backlighting of reserve fuel and the need for emergency injections. In course of the research a fundamentally new system of supplying (transporting) highly concentrated deodorized coal dust (PVKr) with steam ejectors is introduced, instead of existing transport systems, a highly concentrated coal dust feed from piles to burners by pneumatic transport under pressure of a blower fan, and the design speed at the outlet of the burner is: 1) secondary air – 25–30 m/s; 2) gas-air mixture during transportation of dust МВ – 25–28 m/s; 3) aerosomes for transportation of dust PVКr – 18–20 m/s. A steam-ejector burner is installed in a direct-current burner, in a branch pipe of a primary air, a pipe of 377 mm in diameter, in which a dust-air mixture is produced (discharging of a dusty, dusty exhaust dryer (gas-air mixture) by a single-ventilated closed-circuit sawing boiler). The device is a pipe with a diameter of 133×9 mm, at the end of the pipe, which is included in the furnace, a nozzle mounted is a stainless steel cutter, which provides a wide-conic leakage of a dust-vapour-steam mixture and a reliable aerodynamic mixing with secondary air. Thus, we have come to the following conclusions. The reconstruction of the boiler unit TP-100A enables achieving an increase in the installed electric power of the power unit to a value not less than 210 MWt without increasing the cost of fresh steam, improving the technical and economic performance of the equipment, restoring the steam resource of the boiler elements, boosting the boiler efficiency to a value not lower than 90 %, as well as prolongation of the operation life of the boiler elements, pipelines within the boiler, steam lines, pressure vessels, which are not subject to replacement, up to a minimum of 40 thousand hours.