JPS62190314A - High load combustion method for coal and water slurry and device thereof - Google Patents

Abstract

PURPOSE:To be applicable to a boiler which burns fuel containing a small amount of an ash content, by a method wherein fuel is burnt at a temperature higher than a melting point of an ash content, and by dint of a swirl force, molten ash is carried to a collecting part for collection. CONSTITUTION:A high load melting combustion furnace 1, with which a primary combustion furnace is formed, is provided at the one end with a coal and water slurry (CWS) spray nozzle 2 and at the other end with a combustion gas outlet 3. Primary air being rich in oxygen and about 10-30% of a coal combustion theoretical air amount is fed in a primary air swirl chamber 4, formed to the outer periphery of an injection nozzle 2, through primary air swirl vanes 5. In a position right subsequent to an ignition part 6, igniting the CWS and stabilizing flame, secondary air is fed in a furnace 1 through an introduction pipe 8 by means of secondary air swirl vanes 7 as the secondary air is swirled at a high speed. Coal particle of CWS is forcibly collided with the furnace wall by dint of a centrifugal force, and during flow down of the coal particle along the furnace wall, high load swirl combustion is performed in a high temperature range higher than an ash melting point. Combustion of CWS is about completed, and molten ash is discharged through a molten ash take-out port 9 for removal. Combustion gas and unburnt gas freed of an ash content is carried through an outlet 3 to the combustion chamber of a boiler 14.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention removes ash during the combustion process of CWS.
This paper presents a CWSO high-load combustion method and its device that expands the scope of application to boilers using CWS as fuel and promotes the commercialization of CWS.

Conventional technology CWS is a fuel made by adding additives to pulverized coal using water as a solvent to form a slurry, and there are two ways to produce CWS: one that is deashed and one that is not deashed. Undeashed ones contain 10 to 30% ash, and even deashed ones have a commercial limit of about 3% using current deashing technology. The advantages of CWS include that it can be handled in the same way as liquid fuel, and because it contains water, there is no risk of spontaneous combustion, making it convenient to store and handle. Naturally, it is necessary to have a boiler structure that takes into account the high concentration of ash, similar to a pulverized coal boiler, but the 3% ash content even for deashed CWS requires consideration of the following in the boiler structure compared to, for example, a heavy oil boiler. I don't get it.

Combustion chamber types that can be used in existing installations include pulverized coal combustion boilers that can collect and discharge ash in the furnace, or traveling stoker boilers that allow ash to fall to the bottom of the furnace. It is limited to those whose pitch etc. are carved into highly concentrated fly ash.

In particular, when CWS is applied to fuel conversion of boilers that burn fuel with low ash content such as heavy oil, the modification will be large-scale or the scope of modification will be very narrow, which is a factor that hinders the commercialization of CWS. Become.

However, the number of installed boilers does not include the above ash content.
In other words, it is difficult to say that fly ash is not taken into consideration.
Although technology to reduce the ash content of CWS to around 1% is under development, the increase in CWS manufacturing costs is unavoidable, and this reduces the benefits of fuel conversion, making it difficult to provide a realistic solution.

Problems to be Solved by the Invention The purpose of the present invention is to solve the problem of C
Heavy oil regardless of whether the WS is already installed or newly installed.

Applied to the same boiler structure as a gas or other fluid fuel combustion boiler, it reduces the cost of modification and expands the range of boiler models that can be modified in the case of existing installations, and reduces equipment costs by making the boiler more compact in the case of new installations. In order to promote the commercialization of CWS fuel, it is an object of the present invention to provide a combustion method and apparatus that remove most of the ash during the combustion process.

Means for solving the problems, that is, the combustion method of the present invention is a combustion method in which CWS is burned at a temperature higher than the melting point of the coal ash constituting the CWS.
This applies to S.

CWS usually costs 150,000 to 200,00 oKc-
Although combustion is performed with a furnace load of about 1/n+, in the present invention, the furnace load is 1,500,000 to 10,000,000"
A furnace that performs high-load combustion at a furnace load of /- and raises the temperature inside the furnace to 1,500 to 1,600 degrees Celsius, which is the melting point of coal ash, and burns the CWS while melting the coal ash and letting it flow out in liquid form and remove it. It is.

As a specific means, a CWS primary combustion furnace is used which has a CWS spray nozzle at one end and a combustion gas outlet at the other end, and a primary air swirling chamber is provided around the outer periphery of the cws 1llt nozzle. An inlet for introducing a high-speed swirling flow of secondary air is formed at the rear of the section, and a molten ash outlet is formed at the bottom of the furnace peripheral wall near the outlet, and this section is carved into the gas flow to create a horizontal or downward slope. This is what I did.

Therefore, in this furnace, the ignition zone is formed by spraying CWS into the swirling flow of primary air, and immediately after that, the CWS is formed by introducing a high-speed swirling flow of secondary air.
The coal particles are pressed against the furnace peripheral wall by centrifugal force,
Combustion of the CWS is almost completed by swirling combustion at a high temperature above the melting point of the ash while flowing down the furnace wall, and then the molten ash is removed from the furnace wall, and combustion gas and unburned gas are is sent to a secondary combustion furnace for complete combustion.

Embodiment Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

In the figure, reference numeral 1 denotes a high-load melting and combustion furnace constituting a primary combustion furnace, in which a CWSII mist nozzle 2 is provided at one end and a combustion gas outlet 3 is formed at the other end.

A primary air swirling chamber 4 is provided on the outer periphery of the spray nozzle 2.
is provided, and primary air rich in oxygen is fed into the section 4 via a primary air swirler 5 in an amount of about 10 to 30% of the theoretical coal combustion air amount.

6 is an ignition part that stabilizes the ignition and flame of the CWS, and a high-speed swirling flow of secondary air is formed immediately after the core part. Therefore, secondary air swirl vanes 7 are formed on the furnace peripheral wall, and the secondary air is swirled from the inlet pipe 8 into the furnace through the secondary air swirl vanes 7 at high speed, and the theoretical amount of air for coal combustion is 70 to 10%.
Approximately 0% (sum of primary air amount) is fed.

By feeding this high-speed swirling flow of secondary air, the coal particles in the CWS are pressed against the furnace peripheral wall by centrifugal force, and while flowing down the furnace peripheral wall, the coal particles are heated to 1,500 m
A high-load swirl combustion is carried out at a furnace load of 000 to 10,000,000 K-/age, thereby almost completing the combustion of the CWS.

A molten ash outlet 9 is formed in the lower part of the furnace peripheral wall near the combustion furnace outlet, and molten ash generated by high-load swirl combustion while flowing down the furnace peripheral wall is discharged and removed from the molten ash outlet 9. Swirling combustion gas flow can also be done with the furnace horizontal, but
It is better to make the furnace a little downward slope.

The combustion gas and unburnt gas from which most of the ash content has been removed (65-90%) in this way are sent through the outlet 3 to the combustion chamber of a suitable boiler.

FIG. 4 is a block diagram of a CWS fuel combustion boiler equipped with a CWS high-load melting-combustion furnace according to the present invention, and shows a primary air supply line equipped with a high-load melting-combustion furnace 1 and an oxygen enrichment device 11. 12, CW S supply device] 3, and boiler 1
4 and U economizer 15, secondary air and tertiary air supply line 16, air preheater 17 and secondary forced fan 1
8, a dust collector 19, an induction fan 20, etc.

In the case shown in the figure, since most of the ash from the CWS is removed in the high-load melting and combustion furnace 1, almost no ash is generated due to combustion of unburned gas in the boiler 14. can have a boiler structure that burns fuel with low ash content.

Effects of the Invention The present invention burns CWS at a high temperature higher than the melting point of ash in a high-load melting and combustion furnace, and uses swirling force to cause the molten ash to reach the collection section and collect it. ,
CWS can be applied to boiler structures that burn fuel with low ash content.

When the amount of primary air is set to 10 to 30% of the theoretical air amount and this air is swirled as oxygen-rich air, very stable ignition and flame can be obtained.

[Brief Description of the Drawings] Fig. 1 is a cross-sectional view of a furnace for carrying out the method and apparatus of the present invention, Fig. 2 is a cross-sectional view taken along -■ in Fig. 1, and Fig. 3 is a cross-sectional view taken along -■ in Fig. 1. -■ Cross-sectional view, FIG. 4 shows a configuration diagram of a CWS fuel combustion boiler.

Claims (4)

[Claims] (1) In the primary combustion furnace, an ignition zone is formed by spraying coal, water, and slurry (hereinafter referred to as CWS) into the swirling flow of primary air, and immediately after that, a high-speed swirling flow of secondary air is introduced. By doing so, the CWS coal particles are pressed against the furnace peripheral wall by centrifugal force, and swirl combustion is performed at a high temperature region above the melting point of the ash while flowing down the furnace peripheral wall.
CWS high-load combustion is characterized in that after almost complete combustion, molten ash is removed from the furnace peripheral wall, and then the combustion gas and unburned gas are sent to a secondary combustion furnace for complete combustion. Method. (2) The amount of primary air is 10 to 30% of the theoretical air amount,
2. A high-load combustion method for CWS according to claim 1, characterized in that the oxygen-rich air is introduced in a swirling manner. (3) A CWS primary combustion furnace having a CWS spray nozzle at one end and a combustion gas outlet at the other end, wherein the CWS
A primary air swirling chamber is provided on the outer periphery of the spray nozzle, and an inlet is formed behind the ignition section to feed a high-speed swirling flow of secondary air.
A high-load combustion device for CWS, characterized in that a molten ash outlet is formed in the lower part of the furnace peripheral wall near the outlet, and the furnace is oriented horizontally or downwardly with respect to the gas flow. (4) High-load combustion in the CWS according to claim 3, characterized in that the outlet of the combustion gas of the primary combustion furnace is connected to the combustion chamber of a boiler suitable for burning fluid fuel with a low ash content. Device.