JPS6234085Y2 - - Google Patents

Description

[Detailed description of the invention] Unlike conventional continuous combustion equipment using compressed air, this invention completely burns pulverized coal with pure oxygen in a closed combustion tower, thereby reducing the production of nitrogen oxides (NOx) in the combustion gas. This is a non-polluting pulverized coal continuous combustion device. More specifically, pulverized coal is uniformly dispersed by injecting high-pressure carbon dioxide gas, which is an inert gas, into a mixing chamber to form an aerosol, which is ejected from the center nozzle of a concentric double nozzle burner, and pure oxygen is ejected from the outer nozzle. The mixture is ignited and the pulverized coal becomes an aerosol (gas).
To provide a device for complete combustion without generating NOx.

In general, continuous combustion of pulverized coal is an old technology and is widely used industrially. However, since it uses atmospheric oxygen as an oxidizing agent, it is inevitably a source of pollution due to the presence of nitrogen, which makes up 80% of the air.
This is disadvantageous due to the generation of NOx. The pulverized coal continuous combustion device of the present invention uses only pure oxygen as the oxidizing agent, and during complete combustion in a closed combustion furnace, air is shut off and nitrogen is not mixed in. Therefore, NOx is essentially not generated and no exhaust gas is emitted. is non-polluting as it only emits water vapor and carbon dioxide.

The inventors of the present invention previously published Japanese Patent Application Laid-Open No. 52-48704 (Patent Publication No. 59-16161) to eliminate NOx by using a pure oxygen complete combustion method for hydrocarbon fluid fuels (petroleum-based liquid fuels, natural gas, etc.). A method and apparatus for producing a high temperature, high pressure energy gas is disclosed. For example, as seen in the combustion of acetylene burners used in gas welding, the combustion of hydrocarbon fuels (chemically known as oxidation) using pure oxygen as the oxidizing agent produces complete combustion (C _n H _o +O ₂ →H ₂ O
+CO ₂ ), so at the tip of that pale flame,
High temperatures exceeding 3000℃ occur. Gas welding utilizes this high temperature.

In the above invention, water is injected into the closed combustion chamber to cool the flame temperature of the burner from 3000℃ to 1000℃ or less, and the generated water vapor and the
The idea is to produce a high-temperature, high-pressure energy gas consisting of a mixture of combustion gas and water vapor that does not contain any NOx.

In this non-polluting combustion method, this invention burns solid fuel as a fluid by pulverizing coal, which is normally burned in lumps, into pulverized coal, and aerosolizing it with high-pressure carbon dioxide gas. The purpose is to provide a continuous combustion device for pulverized coal.

The continuous pulverized coal combustion device of the present invention ejects pulverized coal aerosolized with carbon dioxide gas from the center nozzle of a gas burner with double concentric nozzles, ejects pure oxygen from the outer nozzle, and ignites the pulverized coal as described above. In order to uniformly disperse the pulverized coal particles in the carbon dioxide gas stream and form a solid gas aerosol during continuous complete combustion, a mixing chamber is provided in front of the burner, and at the lower end of this mixing chamber, The mixing chamber is characterized by a design in which a spiral powder feeder and a high-pressure carbon dioxide gas jetting nozzle are arranged so that the pulverized coal is sufficiently aerosolized within the mixing chamber.

The attached drawing shows the pulverized coal continuous combustion device of the present invention and the pulverized coal that is completely combusted by this device.
This is a schematic diagram illustrating an example in which a device for fully utilizing thermal energy is incorporated into a closed combustion furnace since the combustion occurs as an incandescent high-temperature flame at temperatures above .degree. C.

Hereinafter, the present invention will be explained based on this drawing.

Pulverized coal particles 2 in the pulverized coal raw material tank 1 are sent to a mixing chamber 8 by a spiral screw granule feeder 3. This spiral screw granule feeding device 3 is similar to those used in plastic pellet molding machines, and has a cylindrical body opening at the lower end of the mixing chamber 8, and a screw rotating along its central axis. A spiral type powder feeder 4 is driven by the rotation of a motor 5.

At the bottom of the mixture 8, a high-pressure carbon dioxide gas introduction pipe 7 is opened at the opening of the granule supply device 3, and carbon dioxide gas, which is appropriately pressure-regulated and sent from the high-pressure carbon dioxide cylinder 6, is injected into the mixing chamber. I'm starting to do that. The mixing chamber should have a volume sufficient to achieve aerosolization of the pulverized coal particles and carbon dioxide gas.

The pulverized coal particles forced out from the powder supply device 3 to the bottom of the mixing chamber are dispersed by the high-pressure carbon dioxide gas opening adjacent thereto, forming a uniform aerosol. In order to facilitate the formation of aerosol, the mixing chamber can be made into a cylindrical shape, and the lower part can be made into a circular shape so that the carbon dioxide gas introduced from the bottom can be injected from the tangential direction.

The aerosol formed in the mixing chamber, in which pulverized coal particles are uniformly suspended in carbon dioxide gas, is ejected from the upper end of the mixing chamber through the center pipe of the concentric double nozzle burner 10 into the closed combustion tower 11. Nozzle 10
The outer tube is a jet hole for pure oxygen sent from the high-pressure oxygen cylinder 9, and the pulverized coal aerosol and pure oxygen spouted from the central tube are mixed at the nozzle burner outlet and ejected, and an electric spark placed at the tip of the nozzle is used. It is ignited by other ignition means (not shown).
Since pulverized coal aerosol can be burned in exactly the same way as ordinary gas fuel, the nozzle can be the same type of concentric double nozzle as in ordinary welding gas burners, and once ignited, it burns continuously and smoothly like in welding gas burners. burns.

The burner part of the combustion apparatus of the present invention is usually installed at the center of the lower end of the closed combustion tower.The pulverized coal usually contains 1.0% to 10.0% ash depending on the quality of raw coal and the production area. These ash precipitate in the form of fine powder when the pulverized coal is completely combusted, so the closed combustion tower 11
Make it into a cylindrical tower shape with a height of around 10m and about 1/2 inch from the lower end of this tower.
A burner 10 is installed at 3, and a 2 to 3 m funnel-shaped ash settling space 12 is provided below the burner, from which the precipitated ash is removed. If necessary, a Kottrell electric dust collector can be incorporated to promote settling of ash. The burner flame in this closed combustion tower has a high temperature of over 3000℃, so it is impossible to use it as thermal energy. The above-mentioned high-temperature, high-pressure energy gas generator according to the inventor's prior art injects water and uses the steam heat to lower the temperature inside the combustion tower to below 1000°C, at the same time generating high-temperature, high-pressure gas to power gas turbines and steam turbines. I made it move. However, in the case of continuous combustion of pulverized coal, it is difficult to completely separate the ash content, so in order to lower the temperature of the combustion flame, which is over 3000℃, a water tube of a water tube boiler is installed at the top of the burner, and a large amount of cold water is forced to flow through it. The flame temperature is lowered to below 1000℃, and the steam generated in the water tube through this heat exchange is used to drive a steam turbine and generate electricity, while the gas (CO ₂ + H ₂ O) inside the tower, which has dropped to 1000℃, is pumped to the top. The jet is ejected from the nozzle at a high pressure of about 100 atmospheres, first by a gas turbine, then by a steam turbine (both not shown).
so that it turns. This is the so-called Combined
System (combined system), which is a companion to the Moonlight Project proposed by the Agency of Industrial Science and Technology. However, there is currently no equipment that can withstand heat and pressure of 1000 degrees Celsius, so the inventor built a combustion tower using the highest heat-resistant material on the market (Incoloy, sold by Sumitomo Steel) and lined the inner walls with firebrick. , water tube boiler 1 connected from water supply pipe 13
We designed a cooling method using 5 cold water pipes. This cooling water is made to contribute to cooling the temperature inside the tower by passing through the feed water preheating coil 14 in the upper space of the combustion tower.

The technology for combustion of pulverized coal with air oxygen has already been established and does not require any special operating conditions when using the combustion device of the present invention. Moreover, unlike conventional pulverized coal combustion burners, the device of the present invention does not eject high-pressure air and pulverized coal from a single-hole nozzle and simultaneously ignite and burn the pulverized coal at the same time as aerosolization. Since it is intended to achieve complete combustion by separating and igniting the gas aerosol and pure oxygen, it has the characteristic that it does not generate pollution sources such as NOx, which is inevitably produced with conventional technology. Also, the aforementioned Tokkai Sho
52-48704 (Special Publication No. 59-16161), it is a unique method that enables continuous combustion by converting solid fuel into fluid in the form of aerosol, which is used to generate non-polluting, high-temperature, high-pressure energy gas. It is something.

In addition, high-temperature combustion gas is cooled by water injection to
It is also possible to lower the temperature to 2000℃ and use it as a heat source for MHD power generation.

[Brief explanation of drawings]

The attached drawings show the pollution-free pulverized coal combustion device of the present invention,
This figure shows an example of a gas and steam turbine combined system that effectively utilizes the device. 1...Pulverized coal raw material tank, 2...Pulverized coal particles, 3...
...Powder feeder, 6...High pressure carbon dioxide cylinder, 7...
...Introduction pipe, 8...Mixing chamber, 9...High pressure oxygen cylinder, 10...Nozzle, 11...Closed combustion tower, 12
...ash settling space, 13...water supply pipe, 15...water tube boiler.

Claims (1)

[Claims for Utility Model Registration] (1) Pulverized coal particles aerosolized with inert, non-flammable carbon dioxide gas and pure oxygen are ejected from a gas burner with a concentric double nozzle and ignited. This is a non-polluting pulverized coal continuous combustion device for continuous and complete combustion, and a mixing chamber for uniformly dispersing pulverized coal particles by a high-pressure carbon dioxide gas flow to form a solid-gas aerosol is provided in the center pipe of the double nozzle. A continuous pulverized coal combustion device characterized by having a coal ash settling chamber placed in front of the closed combustion tower and at the bottom of the closed combustion tower. (2) The continuous combustion of pulverized coal according to claim 1 of the utility model registration claim, which is equipped with an outlet of a pulverized coal feeder that opens at the bottom of the mixing chamber and a high-pressure carbon dioxide jet pipe that opens adjacent thereto. Device. (3) The pulverized coal feeder is equipped with a spiral screw type feeder that operates along its central axis;
A pulverized coal continuous combustion device according to claim 2 of the utility model registration claim. (4) The pulverized coal continuous combustion device according to claim 1, wherein the mixing chamber has a volume sufficient to achieve aerosolization of pulverized coal particles and carbon dioxide gas.