JPH05500024A - Method for reducing wear of nozzles or other delivery means - 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] METHODS FOR REDUCING WEAR OF NOZZLES OR OTHER DELIVERY MEANS FIELD OF THE INVENTION The present invention provides a method for separating gaseous pollutants from flue gas containing fly ash. The nozzle used when a slurry of granular adsorbent suspended in water is atomized in a reactor. The present invention relates to a method for reducing wear on a feeder or other delivery means.

The flue gas is fed into the reactor along with most of its fly ash content. minute The slurry is mixed with flue gas. Water is similar to the reaction product obtained by evaporation. and unreacted adsorbent and fly ash are dried in the reactor and/or downstream filter. It is separated from the flue gas as a dry powder, with some of this separated material becoming finely divided. classified to form a first portion consisting of particles and a second portion consisting of coarse particles; Only the first part is recycled to be used again in the reactor.

Conventional technology Conventional devices for cleaning flue gases, for example from coal combustion, often , only has a dust separator to separate the fly ash from the flue gas. death However, flue gas gases such as sulfur dioxide and gaseous hydrogen chloride These pollutants are not removed and are released into the atmosphere, where they pose a major threat to the environment. It becomes powerful.

A contact reactor is used as a device for cleaning flue gas. or) could greatly reduce this threat to the environment. Wear. In a contact reactor, the flue gas reacts with gaseous contaminants to remove these contaminants. It is mixed with an adsorbent that converts the material into particulate contaminants that can be separated in conventional separators.

Therefore, when retrofitting equipment, catalytic reactors are often placed upstream of the existing separator so that there is no need to add another separator.

Adsorbent fed to a catalytic reactor cannot be fully used after just one pass through the system. I couldn't do it. To reduce operating costs, the adsorbent is typically Recycled many times. Combine unreacted adsorbent with reaction products and fly ash. and recycled to the catalytic reactor, for example in the form of a slurry. This sura The lees become atomized as they exit the compressed air nozzle or rotating means at high speed.

Fly ash contains relatively coarse and very hard particles, so it is difficult to use a nozzle when refining it. or equivalent supply means.

This means that the nozzle or equivalent supply means must be replaced frequently. This means that this is both costly and time consuming.

Summary of the invention Technical issues Fly ash, especially fly ash from coal, is used as an abrasive in many contexts. Contains large amounts of oxides used in Therefore, fly ash or fly up Problems always arise when transporting materials containing powder in gas or liquid streams.

The wear experienced on the conveying device is highly dependent on the velocity of the fly ash particles. speed The faster the speed, the greater the wear. In curved narrow passages and stop valves, This wear requires repair at short time intervals.

It is therefore an object of the present invention to extend to the nozzle or equivalent feed means of a catalytic reactor. The object of the present invention is to provide a simple and effective method for reducing wear and tear.

Solution to problem The present invention utilizes a nozzle during slurry atomization in a reactor where the adsorbent is recycled. or equivalently, the problem of wear on the supply means can be reduced by using large particles. The part of the fly ash that has been recycled in front of the recycling system or in the recycling system can be reduced by proper separation. The heaviest particles have the greatest luck. It has the highest kinetic energy and momentum, making it more effective than smaller particles of the same composition. Causes significant wear and tear.

Coarse fly ash particles can be ejected in several different ways and according to a number of physical principles. can. Gravity, inertial force, electric force, magnetic force, etc. can be used. The discharge is from the contact method reactor. can be carried out in advance or in a catalytic reactor or in the recycling part of the system. .

A single cyclone separator or screen separator installed before the reactor Very large particles can be separated before they reach the reactor. Appropriately If the designed reactor is adapted to use inertial effects or gravity, It also functions as a separator. Parts separated in the reactor are not recycled at all. Fly in the recycled material if it is only separated by a stream filter. Specific separation of the ash portion can be performed.

However, work carried out in flue gas ducts is usually quite expensive. and require long periods of stoppage during assembly. Therefore, the present invention It is suggested that the ash particles be separated in the recycling process.

This can be done in essentially the same way as in flue gas ducts, but This provides the advantage that the flow to be treated is relatively small. However, one One condition is when coarse fly ash particles are mixed with particles containing incompletely reacted adsorbent. is clearly different. On the other hand, useful materials are separated in an undesirable manner.

Typically, the fly ash particle size distribution is determined to a large extent by contact methods of the type included in this application. The adsorbent introduced into the reactor is preferably coarser than the particles of slaked lime suspended in water. stomach. Thus, part of the fly ash can be separated without removing most of the adsorbent. It is theoretically possible to separate them. However, in reality, slaked lime is a mass of particles. Consists of. These clumps are of the same size as the fly ash particles that are desired to be separated. Sometimes it's a pain. Therefore, general dynamic separators do not always give satisfactory results. It does not bring about

The invention therefore suggests performing the separation in the liquid phase. This is recycled The dry powder material, now available as a sorbent, is suspended in a liquid such as water to The resulting slurry is passed through a device that separates it into coarse and fine particles. It is done properly by doing so. This division is, for example, an electric force in a particular state or by magnetic force, but preferably by a motion such as a hydrocyclone. This is done in a physical separator.

Example A coal-fired central boiler equipped with suitable equipment for carrying out the method according to the invention - This book with reference to the attached drawings showing the equipment for cleaning the flue gases from the plant. The invention will be described in detail below.

The flue gases formed during the combustion of coal in the central boiler plant 1 are used for air preheating It is introduced into vessel 2. This preheater is connected to the central boiler plant via duct 2a. to transfer heat from the hot flue gases to the combustion air supplied by fan 3 It has become.

The flue gas is then passed through duct 4 without prior separation of the fly ash content. into the catalytic reactor 5, where it is mixed with a granular adsorbent, preferably slaked lime. will be combined. The adsorbent contains gaseous contaminants such as sulfur dioxide and gaseous hydrogen chloride. There is reactivity regarding The adsorbent is supplied to the reactor via conduit 7 in the form of an aqueous slurry. is supplied to a nozzle assembly 6 mounted on the top of the. Preparation of slurry and its composition The configuration will be explained in detail later in this specification.

Nozzle assemblies are described, for example, in European patents 82110320.7 and 8585011. It may be designed as disclosed in 2.5.

In the nozzle assembly, the slurry is supplied to the nozzle assembly via a conduit 8 under the pressure of the slurry. The particles are atomized by the air supplied at higher pressures. In the nozzle assembly, the air The slurry flows at high speed through the nozzle in the form of a jet of finely divided mist 9. This slurry breaks down as it leaves the nozzle of the tube assembly.

Contacting these fog jets so that effective mixing of the flue gas and slurry takes place Spray inside reactor 5.

The water in the slurry evaporates upon contact with the flue gas, and the gaseous pollutants in the flue gas are absorbed. As soon as it reacts with the adhesive, it transforms into particulate pollutants.

Among these particulate contaminants, heavy particles, unreacted adsorbents, and flue gas Eash falls into the dust hopper 10 formed at the bottom of the contact method reactor. . The remaining particles are introduced by the flue gas through the duct 12 into the electrostatic precipitator 13. Ru. In this precipitator these particles are separated from the flue gas, which is passed through the duct 14. through the flue gas fan 15, which collects particulate pollutants and duct 16 to release the flue gas from which gaseous pollutants have been removed into the atmosphere. and supplied to the chimney 17.

The particles separated by the electrostatic precipitator 13 are collected in a dust hop formed at the bottom of this precipitator. Collected within the first 18 pages. These particles are transported by air through conduit 19 into container 20. mixed in this container with the water supplied through conduit 21 by a stirrer 22. be done. As a result, the agglomerates formed from adsorbent particles are broken down. about this See the beginning of this specification. The resulting slurry is passed through conduit 23 to the liquid supply. Pass it through Ikron 24.

In a hydrocyclone, the particles carried by the water are coarse particles, mainly fly ash. is thrown against the wall of the hydrocyclone and falls onto the funnel-shaped bottom of the cyclone. It is classified as lower. These particles are collected on the bottom of the hydrocyclone From there, the slurry is conveyed along with the water content through a conduit 25 to a mixer 26.

In the mixer, coarse particles of slurry are collected in dust hopper 10 and passed through conduit 27. through which the particles are fed into the mixer.

The water of the last-mentioned particulate slurry consisting mainly of heavy fly ash particles. Using special humidifiers by mixing coarse particles carried by A well-moistened residual product is obtained without the need for it. The residual product is then transferred to conduit 2 9 to a storage bin 28.

On the other hand, the fine particles of the slurry, along with most of the water in the slurry, are trapped in the hydrocyclone. Fresh water passes from the center through conduit 30 to container 31 and is supplied through conduit 32. adsorbent, preferably slaked lime, in a container 31 by means of a stirrer 33. So This mixture is then fed through conduit 7 to catalytic reactor 5. Regarding this point Please refer to the beginning of the packing.

Of course, the invention is not limited to the embodiments described above, but within the scope of the appended claims. It can be modified in various ways.

For example, a dynamic separator such as a cyclone can separate particles into coarse and fine parts. Instead, it can be done with electric or magnetic force.

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Claims (6)

[Claims] 1. Granules are used to separate gaseous pollutants from flue gases containing fly ash. Nozzle used to atomize slurry of adsorbent suspended in water in reactor (5) A method for reducing wear on a flue gas or other supply means, the method comprising: is fed into the reactor together with most of the fly ash content, and a small amount of fly ash is fed into the reactor. A finely divided slurry is supplied and the finely divided slurry is passed through the flue gas in this reactor. The water is evaporated and the resulting reaction products as well as unreacted adsorbent and fluid are mixed with Eash is removed from the flue as a dry powder in the reactor and/or downstream filter (13). A portion of the separated material is separated from the first material consisting of fine particles. fraction and a second portion consisting of coarse particles, said first portion only The separated material is recycled to be used again in the reactor. A method characterized in that said portion of the material is suspended in a liquid before being classified. 2. A method according to claim 1, characterized in that the liquid is water. 3. The first part is treated with fresh adsorbent before being recycled to the reactor (5). 3. A method according to claim 1 or 2, characterized in that they are mixed. 4. Claim 1, characterized in that the classification is carried out by a dynamic separator (24), 2 or 3. 5. Claim characterized in that the dynamic separator is a hydrocyclone (24). The method described in 4. 6. Claim 1, 2, or 2, wherein the classification is performed by electric force or magnetic force. is the method described in 3.