JPS5837409A - Structure of pulverized coal combustion chamber - Google Patents

Abstract

PURPOSE:To completely burn char and reduce unburnt matter in ash by a structure wherein refractory material is line on the water-cooled wall over the two- stage combustion zone of the pulverized coal combustion chamber for two-stage combustion in order to elevate the combustion temperature within the two-stage combustion zone. CONSTITUTION:The pulverized coal combustion chamber 1 is usually surrounded by water-cooled wall, equipped with a pulverized coal burner 2 and supplied with two-stage combustion air from an air blow-in port 3 at the location as indicated with the dash line with the arrow head. Because the combustion temperature within the zone in the neighbourhood of the pluverized coal burner 2 and at the air blow-in port 3 or within the two-stage combustion zone A lowers, when two-stage combustion is performed in said pulverized coal firing chamber 1 for decreasing NOx, the refractory material 4 is lined on the water-cooled wall over the two-stage combustion zone A. Owing to the structure as mentioned above, the combustion temperature within the two-stage combustion zone can be elevated, resulting in completely burning the char and reducing the unburnt matter in ash.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a pulverized coal combustion chamber, and particularly to an improvement of a pulverized coal combustion chamber that performs two-stage combustion.

Low NOx in pulverized coal combustion is achieved by using low NOx burner, 2
Staged combustion and exhaust gas circulation are effective.

A low NOx burner controls the mixing of pulverized coal and combustion air to level out the flame temperature and reduce thermal NOx in particular.
thermal NOx and fuel NOx by lowering the partial pressure of
The exhaust gas circulation reduces NOx by equalizing the flame temperature and promoting the mixing of pulverized coal and combustion air.

However, all of these measures to reduce NOx in pulverized coal combustion lower the flame temperature, especially the flame temperature in the second stage combustion zone, so even if NOx is reduced, the amount of unburned matter in the ash increases. It turns out. In addition, in the second-stage combustion zone, the remaining char that remains after the volatile matter in the pulverized coal is burned in the first-stage combustion zone is burned, but since the temperature in this 2R combustion zone is low, the char is not sufficiently combusted, and the char remains in the ash. This increases the amount of unburned matter.

The present invention has been made in order to eliminate the drawbacks of such conventional low NOx countermeasures for pulverized coal. It is intended to provide a structure with a twist tI8m.

An embodiment of the structure of a pulverized coal combustion chamber according to the present invention will be described in detail below with reference to the drawings. 1 is a pulverized coal combustion chamber, usually with a water-cooled wall.
! It is equipped with a pulverized coal burner 2. and low NOx
As a countermeasure against this, second-stage combustion air is supplied through the air inlet 3 to the position shown in the figure.

When two-stage combustion is performed to reduce NOx using such pulverized coal combustion ml, the combustion temperature in the area near the pulverized coal burner 2 and the air inlet 3, that is, in the second-stage combustion area A, decreases. The water-cooled wall is lined with fireproof material 4.

In this way, the heat generated by the pulverized coal twisting mK in the second stage combustion zone A of pulverized coal combustion ml is cut off by the refractory material 4KII and is not absorbed by the water cooling wall, so the pulverized coal combustion temperature in the second stage combustion zone A is maintained at a high temperature. As a result, the char is sufficiently combusted and the amount of unburned matter in the ash is significantly reduced.

The structure of the pulverized coal combustion chamber of the present invention as described in detail above is such that the water-cooled wall of the two-stage combustion chamber of the pulverized coal combustion chamber that performs two-stage combustion is lined with a refractory material. Since the combustion temperature is raised, the char is sufficiently combusted and the unburned content in the ash is significantly reduced, which is an excellent effect.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an embodiment of the structure of a pulverized coal combustion chamber according to the present invention. 1...Pulverized coal combustion m2...Pulverized coal burner 3...2
Stage combustion air inlet 4... Fireproof material A-... Second stage combustion area Application Person Kawasaki Heavy Industries, Ltd.

Claims (1)

[Claims] A pulverized coal combustion chamber that performs two-stage combustion, characterized in that the peripheral wall of the second-stage combustion zone is lined with a refractory material to increase the combustion temperature in the second-stage combustion zone. The structure of
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