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Combustion device

a combustion device and combustion technology, applied in combustion types, combustion using lump and pulverulent fuel, lighting and heating apparatus, etc., can solve the problems of increasing the occurrence of tube leakage, complex arrangement of ducts, and increasing the difficulty of reducing so as to reduce the nox concentration in the exhaust gas, reduce the nox concentration, and control the thermal absorption of the furnace

Inactive Publication Date: 2013-12-26
MITSUBISHI HITACHIPOWER SYST LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention has several technical effects. Firstly, it enables control of the gas flow and flames in a furnace, which reduces NOx emissions and eliminates the need for a temperature controller on the rear heat transfer surface of the furnace. Secondly, it allows for a simpler combustion gas supply system for multiple burners by collectively supplying gas from one duct. Thirdly, it facilitates the construction of multiple wind boxes and ducts by aligning and installing them on the outer side of the furnace wall. Finally, it facilitates adjustment of the amount of combustion gas supplied to each burner by providing flow rate adjusting means for each wind box.

Problems solved by technology

Therefore, a steam temperature and a metal temperature on a rear heat transfer surface of the boiler rise, and a possibility of occurrence of tube leak increases in design that a heat transfer surface material, arrangement of the heat transfer surface, and others are unchanged from the conventional examples.
Therefore, a design temperature of the rear heat transfer surface must be increased to be higher than those in the conventional examples, and there is a problem that quality of the material must be enhanced in terms of strength and heat resistant properties.
In case of the burner provided with a combustion air nozzle having at least two or more air inflow directions, to connect respective combustion air flow paths of a plurality of burners through a duct on outer wall of a furnace and to provide a common wind box, arrangement of the duct is complicated.

Method used

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Examples

Experimental program
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embodiment 1

[0054]FIG. 3(a) shows a perspective view of the wind box 12 of the pulverized coal burner 19 according to this embodiment, and FIG. 4 shows a cross-sectional view (FIG. 4(a)) taken along a line A-A in FIG. 2 and a cross-sectional view (FIG. 4(b)) taken along a line B-B in FIG. 2. It is to be noted that each dark arrow shown in FIG. 4 and subsequent drawings represents an inflow direction of the combustion air.

[0055]Further, a heavy oil nozzle 7 and the pulverized coal nozzle 3 are not shown in FIG. 4, and the heavy oil nozzle 7 and the pulverized coal nozzle 3 are arranged in a cylindrical through hole of the wind box 12. A furnace wall of the through hole constitutes an outer wall of the secondary air nozzle 8.

[0056]As shown in FIG. 4, the wind box 12 having combustion air inlet openings 12a and 12b provided in a direction vertical to a central axis direction of the pulverized coal burner 19, and the secondary air nozzle 8 is arranged as if it is inserted in the through hole provid...

embodiment 2

[0067]In this embodiment, as shown in FIG. 8 and FIG. 9, a wind box 12 into which combustion air flows only from the upper side that is vertical to a central axis direction of a burner 19 is provided, and a plurality of partition plate 14 and revolving dampers 15 are provided in the wind box 12 so that the momentum of the combustion air injected into a furnace can be deviated depending on each of upper and lower sides by adjusting the dampers 15.

[0068]As shown in FIG. 8, in this embodiment, the partition plates 14 are provided so as to divide into three parts the wind box 12 into which the combustion air flows from one direction, i.e., either upper combustion air inlet opening 12a or 12b vertical to the central axis direction of the burner 19. Furthermore, the dampers 15a, 15b, and 15b as air capacity adjusters are provided on the upstream side of trifurcated air inflow paths in the wind box 12, respectively. Therefore, air flows into the upper side of the burner 19 from a central p...

embodiment 3

[0075]This embodiment shown in FIG. 12 and FIG. 13 has a configuration that a wind box 12 into which combustion air flows only from lower combustion air inlet openings 12a and 12b vertical to a central axis of the burner 19 is provided, the inside of the wind box 12 is partitioned by a plurality of partition plates 14, dampers 15b, 15a, and 15b or 15b, 15aa, 15ab, and 15b are provided in respective combustion air nozzles in the wind box 12 partitioned by the partition plates 14, and the momentum of the combustion air injected into a furnace 18 from the burner 19 is deviated depending on each of upper and lower sides of the burner 19 by adjusting opening / closing degrees of the dampers 15b, 15a, and 15b or 15b, 15aa, 15ab, and 15b.

[0076]In this embodiment shown in FIG. 12, the partition plates 14 and 14 are provided so as to divide the wind box 12, into which the combustion air flows from only one lower direction which is a direction vertical to the central axis direction of the burn...

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Abstract

In a boiler having plurality of burners arranged on a furnace wall of a furnace, each burner includes a cylindrical fuel nozzle for injecting a mixture of fuel and carrier gas therefor into the furnace; one or more cylindrical air nozzles provided on the outer circumference of the nozzle for injecting combustion air into the furnace, and a wind box for supplying combustion air to the nozzles in common. The wind box is provided with openings through which combustion air flows in from one direction perpendicular to the axial direction of the burner, and is partitioned by a partition wall to form plurality of parallel flow paths for the air flowing in through the openings. Some of the plurality of flow paths are connected to an upper part of the combustion air nozzle, and the other flow paths are connected to a lower part of the nozzle.

Description

TECHNICAL FIELD[0001]The present invention relates to a combustion device such as a pulverized coal burning boiler having a pulverized coal burner.BACKGROUND ART[0002]As a combustion method using a pulverized coal burner of a pulverized coal burning boiler, there is adopted a two-stage combustion method that combusts a fuel in an air insufficient state and then complete burning air is supplied from an after air port in order to reduce an emission rate of a nitride oxide (which will be referred to as NOx hereinafter) in a combustion exhaust gas.[0003]To further reduce NOx concentration in the exhaust gas at a boiler furnace outlet, the following means can be used.[0004](1) An after-air port is installed to a high position of a furnace, and a detention time of a combustion gas to reach a NOx reduction region between the burner and the after-air port is increased.[0005](2) An excess air ratio (an input air capacity / a theoretical air capacity) is lowered as much as possible, and thermal...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F23D1/00F23L1/00
CPCF23D1/005F23L1/00F23C6/045F23C2201/101F23D1/00F23M9/02F23L3/00F23L9/00
Inventor OCHI, YUSUKEKURAMASHI, KOUJIKIYAMA, KENJIOKAZAKI, HIROFUMI
Owner MITSUBISHI HITACHIPOWER SYST LTD
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