SU1511533A1 - Device for returning fly ash - Google Patents

Abstract

The invention relates to devices for improving the efficiency of burning solid fuels and can be used in boilers, furnaces and other installations. The aim of the invention is to increase the efficiency of afterburning of ash. The flyback return device contains a ash bunker with an ejector located at its bottom, along the axis of which a loading chamber 4 is installed, connected by a pipeline to a firebox. The ejecting agent enters the narrowing part of the nozzle 3, from where it passes through the cylindrical throat into the annular groove 7. As a result of the sharp impact of the supersonic jet on the barrier in the form of a wall, a shock wave is formed. The shock waves and the gaseous agent flow in the groove 7 enter the chamber 4, where a zone with a vacuum is created, as a result of which the ash from the ash bunker is drawn into the chamber and transported to the firebox. 3 il.

Description

Often it refers to devices designed to improve the efficiency of burning solid fuels, including low-calorie ones, and can be used in boilers, furnaces and other installations.

The purpose of the invention is to increase the efficiency of afterburning of ash.

The frequency of their alternation occurs depending on the size of the groove 7 and the pressure of the gaseous agent.

The shock waves and the gaseous agent flow in the channel 7 flow into the loading chamber 4, on the periphery of the entrance to which a zone with a vacuum is created, as a result of which

Fig. 1 shows a device for carrying out a fly from a ash bunker 1 to entrain a fly ash, a longitudinal section; in figure 2-- section aa in figure 1 | on fig.Z - node I in figure 2.

The flyback return device contains a ash bunker 1 with an ejector 2 located 5 in its bottom part, consisting of a confused nozzle 3, along its axis a circular feed chamber 4 connected by pipeline 5 to the furnace is installed. 20 (An annular groove 7 is formed on the flow exit of the nozzle 3, forming a trapezoidal nozzle profile with a large base 8 facing the loading chamber 4. Side 25 wall 9 of the groove 7 has a sharp edge 10 oriented toward the source of the ejection agent.

The trapezoid profile of the nozzle 3 is connected to the tapering part 11 of the nozzle 30 3 of the cylindrical neck 12,

The loading chamber 4 is located from the end of the nozzle at a distance of B (0.4-2.1) C,

By transferring the filling chamber 4 and pipeline 5 to a variable density floor, uniform distribution of entrainment over the cross section of conduit 5 is achieved. As a result, the entrainment mixture - the gaseous agent is fed into the furnace as a compact torch with a uniform distribution of ash on its cross section. The consequence of this is a quick and complete burnout of the return-. Mrgo in the combustion chamber of ash. Intensification of combustion is largely provided by shock waves propagating into the furnace, generated in nozzle 3 and transported along with the mixture flow into the furnace.

The distance in which the nozzle 3 is located relative to the loading chamber 4 is important in the operation of the return device. It determines not only the fraction of acoustic energy loss to the environment, but also the ejection capacity of the nozzle-loading chamber.

Device return ash works as follows.

The ejecting agent (air or flue gases) enters the tapering part 11 of the nozzle 3, from where it passes through the cylindrical neck 12 into the annular groove 7, which forms the expanding part of the nozzle 3, where the flow is accelerated to supersonic speed. At the exit of the nozzle 3, the flow of the side-wall 9 of the groove 7 is braked. As a result of a sharp impact of a supersonic jet on an obstacle in the form of a wall 9, a shock wave is formed (shock wave), which, propagating in the direction of the exit, interrupts the flow from the throat 12 flow of gaseous agent, the flow of which takes a pulsating character. The degree of compression in the shock wave increases with the flow around the sharp edge 10 of the wall 9. The compression wave (shock wave) is followed by a rarefaction wave.

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ABOUT

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By transferring the filling chamber 4 and pipeline 5 to a variable density floor, uniform distribution of entrainment over the cross section of conduit 5 is achieved. As a result, the entrainment mixture - the gaseous agent is fed into the furnace as a compact torch with a uniform distribution of ash on its cross section. The consequence of this is a quick and complete burnout of the return-. Mrgo in the combustion chamber of ash. Intensification of combustion is largely provided by shock waves propagating into the furnace, generated in nozzle 3 and transported along with the mixture flow into the furnace.

The distance in which the nozzle 3 is located relative to the loading chamber 4 is important in the operation of the returning device. It determines not only the fraction of acoustic energy loss to the environment, but also the ejecting ability of the system1 nozzle-loading chamber.

It was determined experimentally that B (0.4-2.1).

When parameter B is less than 0.4 V, a sharp abrupt change occurs in the amount of incoming ablation due to clogging of the gap between the nozzle and the loading chamber.

When B exceeds the value of 2.1 V, the ejection changes abruptly. the ability of the device to reduce the distribution of acoustic energy into the loading chamber and further into the pipeline.

As a result of the use of the invention, the efficiency of the boiler-unit is increased by 1.5-2% due to the reduction of heat loss with ash and the range of regulation of the thermal stability is increased to 20% nominal.

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Claims (1)

Claim device A flyback return device containing an aeolian bunker with a confusing nozzle located in its bottom part for supplying a high-pressure eningting agent, a circular loading chamber mounted along the axis of the nozzle and connected to the pipeline with a furnace, characterized in that 1 Compiled by E. Merkachev Editor L. Veselovska Tehred M. Didyk Proofreader O. Kravtsova Order 5885/41 Circulation 488 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 115336 The aim is to increase the effect of post-burning of the CNS, an annular groove is formed on the flow outlet of the nozzle, forming a trapezoidal nozzle profile with a large base facing the loading chamber, while the side wall of the groove has a sharp edge oriented toward the entrance to the confuser nozzle. Subscription