JPH01111122A - Cyclone coal combustion furnace system recovering sensible heat of slag - Google Patents

Abstract

PURPOSE:To recover sensible heat of slag and increase an efficiency of a boiler plant by a method wherein the slag under its molten condition of high temperature which is discharged from a cyclone coal furnace is cooled by air and cooling air of which temperature is increased through heat exchanging operation is used as combustion air for fine powder coal. CONSTITUTION:Fine powder coal is ignited within a cyclone coal furnace 1, ashes contained in the fine powder coal are dropped onto a cooling floor 3 of slag within a slag heat exchanging chamber 17. Cooled air fed from a cooling air blower 9 cools molten metal of high temperature. The cooled slag is crushed by a crusher 4 and sent onto a discharging conveyor 6. Cooling air of high temperature is fed into a cyclone separator 8 to separate fine slags, discharges them onto the discharging conveyor 5 located at a lower part. Clean hot air is fed into a suction side of a fine powder coal combustion forced blower 10. The blower 10 may suck hot air and surrounding atmosphere, heat exchange with discharged gas of a boiler 2 by a gas air preheater 12, further increase its temperature and the air is fed into a furnace 1 and acts as combustion air for fine powder coal injected from feeding hole.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a cyclone that burns introduced pulverized coal under conditions of high temperature and high heat load, and discharges the combustion ash attached to the peripheral wall in a molten state. This relates to a boiler that is the antithesis of a coal-fired furnace.

[Conventional technology] The pulverized coal attached to the combustion chamber of the boiler main body is blown out from the inlet hole under conditions of high temperature and high heat load, and the combustion ash adhering to the surrounding wall is discharged in a molten state. In the cyclone coal-fired furnace system, in which combustible combustion gas is sent into the combustion chamber of the boiler main body, the slag discharged from the cyclone coal-fired furnace is dropped through a duct into a water-sealing device filled with water. The slag was coarsened and cooled by cooling, and the cooled coarse slag was discharged by a conveyor and sent to a slag container. This method uses water to cool the slag, so cooling can be done in a short time, the operating cost required for cooling is low because the cooling source is water, the construction cost of cooling equipment is low, and the cooling In addition to making the equipment more compact, this method had the advantage of crushing the slag into coarse particles by pouring the high-temperature slag into water and cooling it rapidly.

[Problems to be Solved by the Invention] However, in the conventional cyclone coal combustion furnace system described above, all the generated slag is poured into water and cooled, so that all the sensible heat of the high temperature slag is absorbed by the cooling water. This has the disadvantage that a large amount of heat is lost because it is consumed as evaporation heat.

[Means for Solving the Problems] As described in the claims, the means for solving the problems described above are provided in a boiler having a cyclone coal-fired furnace, in a boiler downstream of a slag discharge hole of the cyclone coal-fired furnace. A heat exchange chamber was provided on the side, and the heat exchange chamber was provided with means for temporarily retaining slag, means for introducing air for cooling the slag, and means for discharging high temperature air that communicated with the combustion air inlet of the cyclone coal combustion furnace. This is a cyclone coal combustion furnace system that recovers sensible heat from slag.

[Function] First, there is the boiler body, and the combustion chamber of the boiler body has a cyclone coal combustion furnace. There is a slag heat exchange chamber downstream of the slag discharge hole of the cyclone coal combustion furnace. The heat exchange chamber has a means for temporarily retaining the slag, and is connected to a means for introducing air for cooling the slag and a means for discharging high-temperature air. The outlet duct constituting the high-temperature air discharge means leads to the cyclone coal combustion furnace via a cyclone separator, a forced air blower for pulverized coal combustion, a gas air preheater, etc., as necessary. The molten slag produced in the cyclone coal combustion furnace falls into the heat exchange chamber from the slag discharge hole. The cooled air, whose temperature has increased by exchanging heat with the slag in the heat exchange chamber, enters the cyclone separator as necessary, where it is purified by separating fine slag and discharging it onto the slag discharge conveyor at the bottom. It is sent to the suction side of the forced air blower for combustion. The forced air blower for pulverized coal combustion sucks the high-temperature air and atmosphere obtained in this way, exchanges heat with the boiler exhaust gas using a gas air preheater, further raises the temperature, and then transfers it to the cyclone coal combustion furnace. It acts as combustion air for the pulverized coal that is introduced and ejected from the inlet hole. Therefore, according to the present invention, the air is cooled by the high temperature molten slag air discharged from the cyclone coal combustion furnace, and the air heated by heat exchange is used as combustion air for pulverized coal in the cyclone coal combustion furnace. This has the effect of making it possible to recover the sensible heat of the slag.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram of a cyclone coal combustion furnace system for recovering sensible heat from slag, showing one embodiment of the present invention. 1st
In the figure, 1 is a cyclone coal combustion furnace, 2 is a boiler body, 3 is a slag cooling bed for temporarily retaining slag, 4 is a crusher, 5 is a slag discharge conveyor, 6 is a slag bunker, 7 is a slag cooling air outlet duct, and 8 is a slag cooling air outlet duct. Cyclone separator, 9 is a slag cooling air blower, 10 is a forced air blower for pulverized coal combustion, 11 is a duct on the discharge side of the forced air blower for pulverized coal combustion, 12 is a gas air preheater, 13 is a pressure regulator, 14
is an air volume adjustment damper, 15 is an induced draft fan, 16 is a chimney, 1
7 is a slag heat exchange chamber, 18 is a boiler exhaust gas duct, 19
is the slag cooling air inlet duct. In the cyclone coal combustion furnace 1, the pulverized coal ejected from the inlet is burned under conditions of high temperature and high heat load, and the ash in the pulverized coal collides with the surrounding wall due to the swirling force of the combustion gas, adheres to it, and then becomes molten. The slag is discharged from the slag discharge hole and falls onto the slag cooling bed 3 of the slag heat exchange chamber 17 provided at the bottom. Slag cooling bed 3
Cold air is blown from the top of the slag cooling air blower 9 to cool the high temperature molten slag. A slag cooling air outlet duct 7 is installed inside the slag cooling bed 3 to cool the slag on the slag cooling bed 3 and suck in the cooling air that has become hot through heat exchange. The slag cooled on the slag cooling bed 3 falls from the end of the slag cooling bed 3 onto the crusher 4 and is crushed into coarse particles.
The slag is sent onto the lower slag discharge conveyor 5. The coarse slag sent to the slag discharge conveyor 5 is further sent to a slag bunker 6 and stored therein. The high-temperature cooling air sucked inside the slag cooling bed 3 is sent to the cyclone separator 8 with some fine slag suspended, and the fine slag is separated and discharged onto the slag discharge conveyor 5 at the bottom. The clean high-temperature air is introduced into the suction side of the forced air blower 10 for pulverized coal combustion. The forced air blower 10 for pulverized coal combustion sucks the high-temperature air sent in from the cyclone separator 8 and the atmosphere,
After exchanging heat with the exhaust gas of the boiler 2 by the gas-air preheater 12 and further raising the temperature, the air is fed into the cyclone coal combustion furnace 1 and acts as combustion air for the pulverized coal ejected from the feed hole. An air volume adjustment damper 14 is disposed at the outlet duct of the slag cooling air blower 9, and balances the pressure inside the cyclone coal combustion furnace 1 with the internal pressure of the slag heat exchange chamber 17, thereby cooling the slag. This prevents the cooling air sent from the air blower 9 from entering the cyclone coal combustion furnace 1 through the slag discharge hole and becoming excess air, and also prevents the cooling air from flowing into the slag heat exchange chamber 17 from insufficient cooling air volume. This prevents the slag from being insufficiently cooled, resulting in clogging of the slag cooling bed 3 or welding to the crusher 4.

Figures 2 to 4 show other embodiments of the present invention, where Figure 2 is an overall system diagram, Figure 3 is a structural diagram of a slag heat exchange chamber, and Figure 4 is a structural diagram of a slag heat exchange chamber.
The figure is a structural diagram of a vibrating slag cooling bed. In order to simplify the explanation, parts in FIGS. 2 to 4 that have the same functions as in FIG. 1 are designated by the same reference numerals as in FIG. 1. In Figures 2 to 4, 3 is a vibrating slag cooling bed, 20 is an exciter, 21 is a slag cooling bed cooling water artificial pipe, 22 is a slag cooling bed cooling water outlet pipe, 23 is a slag pulverized particle falling hole, and 24 is a It is a cooling air hole. In the cyclone coal combustion furnace 1, the pulverized coal ejected from the inlet is burned under conditions of high temperature and high heat load, and the ash in the pulverized coal collides with the surrounding wall due to the swirling force of the combustion gas, adheres to it, and then becomes molten. The slag is discharged from the slag discharge hole and falls into the slag heat exchange chamber 17 provided at the bottom. The fallen slag is cooled and solidified in a lump by the cold air sent from the slag cooling air blower 9. The solidified slag is coarsely crushed by a crusher 4, and then sent to a lower slag cooling bed 3.
reach the top. The slag cooling bed 3 is formed of a perforated plate having a water-cooled structure, and a plurality of slag cooling beds 3 are provided in the vertical direction, and each of them is given vibration by the vibrator 20. In addition, the slag cooling bed 3 includes slag pulverized particle drop holes 23 and cooling air holes 2.
4 is perforated, and has a structure that allows slag crushed particles to fall from above to below and slag cooling air to pass from below to above. As a result, the slag cooling bed 3
The coarsely crushed slag that has fallen to the top is further cooled by contact with the low-temperature cooling bed and the low-temperature slag-cooling air sent in from below, and is further crushed into fine particles by a vibrating perforated plate. , and fall onto the slag discharge conveyor 5 disposed at the bottom of the slag heat exchange chamber 17. The fine-grained slag that has fallen onto the slag discharge conveyor 5 is sent to a slag bunker 6 and stored. The slag is cooled in the upper part of the crusher 4 and the slag cooling bed 3 in the slag heat exchange chamber 17, and the slag cooling air which has become high temperature through heat exchange,
The suspended fine slag is sent to the cyclone separator 8 through the slag cooling air outlet duct 7, where the fine slag is separated and discharged onto the lower slag discharge conveyor 5, and the clean high temperature air is used for pulverized coal combustion. The air is fed into the suction side of the forced air blower 10. The forced air blower 10 for pulverized coal combustion sucks the high temperature air and atmosphere sent in from the cyclone separator 8, exchanges heat with the exhaust gas of the boiler 2 through the gas air preheater 12, further raises the temperature, and then converts it into cyclone coal. The air is fed into the combustion furnace 1 and acts as combustion air for the pulverized coal ejected from the feed hole. An air volume adjustment damper 14 is disposed at the outlet duct of the slag cooling blower 9, and the slag heat exchange chamber 17 changes the pressure inside the cyclone coal combustion furnace 1.
This prevents the cooling air sent from the slag cooling air blower 9 from entering the cyclone coal combustion furnace 1 from the slag discharge hole and becoming excess air. This prevents the slag from being insufficiently cooled due to an insufficient amount of cooling air sent to the slag heat exchange chamber 17, and from clogging the slag cooling bed 3 or welding to the crusher 4.

[Effects of the Invention] As is clear from the above embodiments, the present invention provides a boiler equipped with a cyclone coal combustion furnace, in which cooling is performed by high temperature molten slag air discharged from the cyclone coal combustion furnace. By using the cooling air heated through heat exchange as combustion air for pulverized coal in a cyclone coal combustion furnace, the sensible heat of the slag is recovered and the plant efficiency of a boiler equipped with a cyclone coal combustion furnace is increased. This has the effect of making it possible to

[Brief explanation of the drawing]

Figures 1 to 4 are examples of a cyclone coal combustion furnace system for recovering sensible heat from slag based on the present invention. Figure 1 is an overall system diagram when a conveyor type is used for the slag cooling bed, and Figure 2 is a slag Figure 3 is a structural diagram of the slag heat exchange chamber in Figure 2, and Figure 4 is a structural diagram of the vibrating slag cooling bed in Figures 2 and 3. . 1... Cyclone coal combustion furnace, 2... Boiler body,
3... Slag cooling bed, 4... Crusher, 5... Slag discharge conveyor, 6... Slag bunker, 7... Slag cooling air outlet duct, 8... Cyclone separator, 9... Slag Cooling air blower, 10... Forced air blower for pulverized coal combustion, 11... Forced air blower discharge side duct for pulverized coal combustion, 12
...Gas air preheater, 13...Pressure regulator,
14... Air volume adjustment damper, 15... Induced draft fan,
16... Chimney, 17... Slag heat exchange chamber, 18... Boiler exhaust gas duct, 19... Slag cooling air inlet duct, 20... Exciter, 21... Slag cooling bed cooling water Inlet pipe, 22...Slag cooling bed cooling water outlet pipe, 23...Slag crushed particle fall hole, 24...Cooling air hole.

Claims (3)

[Claims] (1) In a boiler with a cyclone coal combustion furnace,
A heat exchange chamber is provided downstream of the slag discharge hole of the cyclone coal combustion furnace, and the heat exchange chamber includes a means for temporarily retaining slag, an air introduction means for cooling the slag, and a combustion air intake port of the cyclone coal combustion furnace. A cyclone coal combustion furnace system for recovering sensible heat from slag, characterized by having a high temperature air exhaust means communicating with the slag. (2) A cyclone coal combustion furnace system for recovering sensible heat from slag according to claim (1), wherein the means for temporarily retaining slag is a slag discharge conveyor. (3) A cyclone coal combustion furnace system for recovering sensible heat from slag according to claim (1), wherein the means for temporarily retaining slag is a vibrating perforated plate.