JPH05504615A - A method of feeding a combustor with coal and sulfur absorbent, and a power plant implementing this method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] A method of feeding coal and sulfur absorbent to a combustor and the driving force for carrying out this method plant technical field The present invention provides a combustor that performs combustion in a fluidized bed of granular material, which contains coal and sulfur absorbent. Regarding how to supply. This method mainly involves pumping coal at a pressure significantly higher than atmospheric pressure. The target is a PFBC plant. PFBC is It is an acronym for the term Pressurized Bed Combustion.

Background technology In a power plant of the above type of conventional design, one of the following delivery systems may be used: Used: a) Coal and absorbent are crushed and mixed. This crushing Water to prepare pastes from materials that are Some emulsifiers or oils are added to improve the This paste is pump is delivered to the bed through the nozzle.

This method has several drawbacks and is subject to limitations.

Particle size distribution is important for obtaining excellent conveyance properties. This is a crushing equipment , significantly increases the demands on particle size distribution monitoring. From an economic point of view, This method can only be used with high quality coals with low sulfur and ash content. High ash content For coals that require a lot of sulfur absorbent, the moisture content relative to the amount of coal This has a negative effect on the efficiency of the plant.

b) Crushing and drying the coal and sulfur absorbent, then lock hopper system feed to the bed through.

This method is used for coals with high ash and/or sulfur content.

No addition of water is necessary which reduces efficiency. However, wet particulate material locks Dry the crushed material to prevent it from clogging the hopper and conveying system. A large amount of energy is required for drying. Dry granulated coal is still an explosive hazard. This requires inert gas in the lock hopper system, which requires investment. Significantly increases book and operating costs.

When feeding fine particle coal in a dry state, multiple steps are required to obtain a uniform temperature distribution. Several feed points are required.

These feed points must be located laterally close to each other (the spacing between the feed points should be approximately 5 1m). In order to further improve combustion, the bed should be set at a height of <(2-3m). ) Is it necessary? If this is not done, the fine coal particles will be destroyed before they are combusted. There is a risk of being blown out.

If the bed is raised, the fuel nozzle may also be positioned at a different height and placed in the bottom compartment. Excessive temperatures with the risk of sintering should be avoided. Dried fine coal It is clear that there are considerable difficulties involved in transporting them in such a state.

C) Crushing the coal and delivering it in the form of a paste.

The coal is then crushed into appropriate particle sizes to form a paste. This is coal , which means that they must be crushed to smaller particle sizes on average, thus reducing the crushing cost. It means an increase in usage.

Summary of the invention According to the invention, the coal is fed into a fluidized bed and is combusted therein in a suitable manner. Shredded to large size. This crushed coal is divided into a coarse part and a fine part. Ru.

The fine part is approximately 0. 5-1. Contains coal particles smaller than 0ma+, coarse The grain portion is made to contain between approximately 0.5-1.0 mm and approximately 7 mm of coal.

This coarse-grained coal fraction is then air-loaded separately or with crushed sulfur absorbent. is fed to the combustor through a hopper system and nozzles. The fine coal part is Separation eliminates the risk of explosion when stored in pressurized containers. The risk of clogging of the conveying device when pneumatic conveying is also reduced. Distributes and pressurizes For this purpose, the device described in Swedish patent application 8502301-8 may also be used. can be used.

For particulate parts that pose a risk of explosion, use water and possibly emulsifiers or oil. A paste is prepared by the addition of. Paste is prepared with only a small amount of fuel Therefore, the amount of water added to the total amount of coal is small, and therefore there is only a slight decrease in efficiency. That's it. Since the paste is prepared using only fine grain materials, it contains less moisture. Excellent bomb delivery capability is obtained. The reason is that this paste has a tendency to precipitate. This is because it does not contain coarse particles that tend to clog the sending vibrator.

According to the invention, there is little need to balance the dimensional distribution of the crushed material when carrying out the crushing. Somehow, the crushing is therefore simplified and the energy consumption for crushing coal is This reduces the risk of explosion, and requires less water to be supplied to the combustor. This also avoids a decrease in efficiency due to

The fine coal part is sorted and the coarse coal is fed into the lock hopper system. and sulfur absorbent, there is no risk of explosion or blockage of the lock hopper system. This eliminates risks and increases the reliability of fuel delivery. To reduce the risk of explosion, The containers in the dock hopper system can be heated by air, thus reducing The use of active gases (which are very expensive) is also unnecessary. Also compare the fuel nozzle arrangement with fishing lines etc. and located in a limited area vertically above the combustor, close to the air nozzle at the bottom of the combustor. I can do it.

Brief description of the drawing The invention will now be described in more detail with reference to the accompanying drawing, which shows a combustor, fuel and sulfur Diagrammatically shows the equipment for preparing PFBC and delivering it to a PFBC power plant. , in which case combustion takes place at pressures considerably in excess of atmospheric pressure.

In the figure, numeral 10 indicates a combustor placed within a pressure vessel 12. Conduit 1 in space 13 4, compressed air is supplied from a compressor (not shown). The combustor 10 is a particulate It includes a fluidizable head 16 of material within which fuel is combusted.

The combustor lO further cools the bed 16 and for the steam turbine (not shown). It has a pipe 18 that generates steam for the purpose. There is plenty of combustion gas coming out of bed 16. Collected within height 20 and carried by conduit 22, the purified water is shown as a cyclone. The dust was led to the chemical plant 24, where it was separated from the dust, and then exited from the cyclone in Kakko. Conduit 26 feeds a gas turbine (not shown). Separated dust is It is discharged from the cyclone 24 by a pipe 28. The fuel paste is pumped It is sent to the combustor through conduit 30 and nozzle 32.

The coarse fuel portion and sulfur absorbent are delivered to the combustor lO through conduit 34 and nozzle 36. supplied to Air is sent to the combustor 10 from the space 13 through the nozzle 38, The material in the bed 16 is fluidized and the supplied fuel is combusted.

The coal coming from the fuel depot 40 is crushed by a mill 42 and sent to a sorting plan and 48. It is divided into a fine grain portion 44 and a coarse grain portion 46. Exited from absorbent storage 5o. The sulfur absorbent is crushed in a crusher 52. The coarse coal portion 46 and the sulfur absorbent are is conveyed through conduit 54 to storage vessel 56 by carrier gas from compressor 58 . having containers 62 and 64 and valves 66 and 68 and rotary valve feeder 70 Through the lock hopper system, the coal and absorbent are delivered to the conveyor vibration 34. , further delivered to the bed by nozzle 36. The carrier gas is passed through conduit 72. The air is taken out from the pressure vessel 12.

Pressure is increased within booster compressor 74.

A container 62 within the lock hopper system 60 can provide compression and release pressure. There is something to be gained and something to be done. For pressurization, the container 62 is a conduit equipped with a valve 63. 61 to a pressure medium source (not shown). Fine coal particles are present Since there is no explosion, there is no risk of explosion, and the container 62 is pressurized with an inert gas. It can be pressurized with air without the need for air pressure. This represents a considerable benefit to the plant. point and simplification. Container 62 is a conduit with a valve 67 to relieve pressure. 65. This conduit 65 is led into an atmospheric pressure space.

The size of the particles depends on the coal bottle and the shape of the particles when they are subjected to crushing operations. large particles and small The boundaries between particles are clear, and if the particles in the crushed material are in the form of flakes, If it is spherical, the amount of gas is small.

The boundary between large particles and small particles is usually within the range of 0.5-1.0. against large particles The maximum dimension should normally not exceed about 7 inches.

The granulated coal portion 44 conveyed to container 76 is mixed with water and optionally other additives. a fuel paste which can be mixed and agitated by an agitator 78 and delivered by a pump; It is said to be 80. This paste 80 is pumped through the conduit 30 and It is delivered to combustor 10 through nozzle 32 . The granular coal portion 44 is a mechanical conveyance device. It may be conveyed to the container 76 by a pneumatic conveying device as shown. Wear. In the latter case, a portion of the sorting plant is connected to the conveying vibrator 84. promotion Gas is obtained by a compressor 58. Coal and carrier gas are stored in the tank above container 76. It is separated in Ikron 86 and falls into this container.

The carrier gas is cleaned with water in the gas scrubber 88 to remove any dust remaining in the carrier gas. Dust is removed. Carrier gas for coarse coal portion 46 is supplied from vessel 56 to conduit 90 The gas is guided to a cyclone 86 and a gas washer 88, where it is cleaned.

Summary book The present invention provides a combustor (10) that performs combustion within a fluidized bed (16) that absorbs coal and sulfur. The present invention relates to a method for supplying an astringent. Coal is crushed and classified into fine particles and coarse particles. be done. The fine particles are soaked in water and possibly oil and/or to form a paste. or mixed with emulsifiers. This is done by pumping a certain number of first nozzles (32). through which it is fed to the bed (16) of the combustor (IO). Coarse coal part is dry directly by air or with one or more lock hopper systems (60 ) and a number of other nozzles (36) to the combustor. This invention is It relates to a power plant for carrying out the method.

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Claims (1)

[Claims] 1. A combustor (10) that performs combustion in a fluidized bed of granular material is provided with coal and sulfur absorbers. In the method of supplying an astringent, crushed coal is divided into a fine part and a coarse part. By adding water and possibly oil and/or emulsifiers, the fine part is A paste is prepared and the paste is pumped through one or more first nozzles. (32) to the fluidized bed of the combustor, and The coarse coal fraction and the crushed absorbent are dried directly with air or one or more lock hopper systems (60) and one or more other nodes; The one characterized in that it is supplied to the combustor through the drain (36). Law. 2. The granular coal fraction is pneumatically transported to a cyclone and/or gas washer (86). The coal portion is separated from the carrier gas in the gas washer, and then the vessel (76 ) for preparing a paste. Method described. 3. The coarse coal portion is pneumatically conveyed to the lock hopper device (60), and the conveying gas purified in a cyclone and/or gas washer (88) and freed from the carrier gas. The separated dust is mixed with granulated coal to form part of the prepared fuel paste. 2. The method according to claim 1, wherein: 4. The coarse coal fraction and sulfur absorbent are burned through a common lock hopper system. 2. A method according to claim 1, characterized in that it is fed to a kiln. 5. Dust in the fine coal part and its carrier gas and the carrier gas for the coarse coal part Dust is separated in a common cyclone and/or gas scrubber unit (86). The method according to any one of claims 2 to 4, characterized in that: 6. a combustor ( 10) In a power plant having Sorting plant (48) for dividing crushed coal into fine and coarse parts and, a conveying device (84) for conveying the granulated coal to the paste preparation container (76); Pace where granulated coal fraction can be mixed with water and/or oil and pumped an apparatus (78) for preparing the liquid (80); for pumping the paste to the nozzle (32) in the combustor (10); paste pump (82), coarse coal portion and crushed sulfur absorbent or to a plurality of lock hopper systems (60). The feed pipe (54), coarse coal portion and sulfur absorbent are transferred through the nozzle (36). and one or more ash distribution conveying devices (70, 34) for feeding the ash to the combustor. Power plant with. 7. The combustor (10) is pressurized, i.e. combustion takes place at a pressure considerably above atmospheric pressure. The power plant according to claim 6, characterized in that: 8. Transport fine coal part to cyclone and/or gas washer (86/88) and has a pneumatic conveying device (84) adapted to separate the coal from the conveying gas. The power plant according to claim 6 or 7, characterized in that: 9. For the carrier gas coming out of the separator (56) that separates the coarse coal part and the absorbent An outlet for the cyclone and/or gas washer (86) passes through the conduit (90). /88) to separate dust in the carrier gas. The power plant according to claim 6 or 7.