The method of purification of waste gases
(57) Abstract:Use: for cleaning of gases produced by the combustion, gasification, chemical or metallurgical processes. The inventive method comprises adding to the gases before or after the process of the reagent and/or absorbent interacting with contained in the gases substances polluting the environment, with the formation of the slag separation of gases containing reagent and/or absorbent, two separate gas flow, after which the first stream is introduced into the drying zone, located in the lower part of the reactor irrigation, and the second gas stream is injected into the irrigation zone, located in the upper part of the reactor irrigation to moisten the suspension of gas and reagent and/or absorbent of water and/or steam, moreover, the particles of the slag is separated from the gas in the reactor irrigation, the layer of individual particles of slag support below the level of the input at the bottom of the reactor irrigation, separated wet slag particles and water drops falling down from the top of the reactor irrigation, mixed with particles of slag in the slag layer for homogenization temperature and humidity of the layer of slag. 19 C.p. f-crystals, 1 tab., 4 Il. The invention relates to a method of cleaning gases, which are formed, for example, primestone, polluting the environment, which are contained in these gases are sulphur dioxide, ammonia, chlorine compounds, and fluorine and liquefied hydrocarbons. The invention in particular relates to a method in which a reagent and/or the absorbent reactive contained in gases substances that pollute the environment, is activated by directing gases into the reactor irrigation. The reagent and/or the absorbent is injected directly into the process or added to the gases involved in the process. Gases introduced into the reactor irrigation, in which they are wetted with water or steam, with the aim to activate the reagent contained in the gases. Gases are first received in the lower part of the reactor, and then climb further up in the irrigation zone of the reactor, in which the suspension is formed by gas and reagent, moistened with water or steam. Particle reagent and/or absorbent material that partially or completely reacted, separated on the filter in the upper part of the reactor from the gases before they leave the reactor. As reagents or absorbents used carbonates, oxides and hydroxides, such as alkali or alkaline-earth metals.It is known that the combustion of oil fuel flue gases are formed, which sexmanals depending on the sulphur content of the fuel. Numerous efforts are focused on the search for ways to use fuel containing more and more amount of sulfur, although restrictions on sulfur emissions into the environment are becoming tougher and tougher. Enterprise waste by ashing, the number of which is constantly increasing, also produce flue gases containing sulfur, which must be cleaned to an acceptable level of sulfur content. The flue gases formed in the enterprises of processing waste by ashing, contain, for example, if burned plastic materials, in addition to the SO2and SO3also hydrochloric and hydrofluoric acids, and other harmful gaseous and solid substances.Process gases are produced in many gasification processes, may also contain harmful levels of sulfur compounds and other compounds that need to be separated from the gases before the subsequent processing process gases.Developed several ways to cut sulfur emissions at thermal power stations. The most common method used at the present time, is the cleaning gas in Gazpromavia column, in which the gases is Zia in water is injected into the gas stream, coming after the furnace of the boiler in Gazpromavia column (wet scrubber), while sulfur is absorbed by the aqueous suspension with the formation of sulfate or sulfite calcium
CaO+SO2+1/202__ CaSO4< / BR>or
CaO+SO2__ CaSO3< / BR>The aqueous suspension is injected in such a quantity that formed these connections have no time to lose water and discharged in the form of sludge from the bottom of Gazpromavia columns. The process of washing in Gazpromavia column is complex because it requires the use of devices for the preparation of aqueous suspension for subsequent processing. Moreover, this method usually requires consumption of additional energy for drying the obtained slurry at a special processing plant sludge. For this reason, usually served in a suspension system with a minimum water content to reduce energy costs. Due to the significant quantity of used water suspension, the gas in the scrubber can be cooled to a relatively low temperature and, therefore, the gas discharged from the scrubber, may cause corrosion and clogging of filters. To re-heat the flue gases before they are output from the system is spent on what amounts to about 95%.Recently developed palomaria methods using a scrubber, in which the contact reactor in a stream of hot flue gas through a nozzle inject well sprayed suspension of alkali, in particular, a suspension of calcium hydroxide, and the sulfur oxides are dissolved in water, and after drying the suspension to form connections with lime. The water evaporates in the contact reactor, so that the formed solid waste, the products of the interaction, for example, sulfur and lime can easily be separated from the gases by means of the filter. Attempts have been made to maintain the consistency of the suspension of calcium hydroxide at such a level that the heat contained in flue gases, was enough to evaporate water from the slurry. However, a thick suspension of lime readily forms precipitates on the walls of the reactor and especially around the injectors and can eventually clog the nozzles. Therefore, the reactor has to make a large enough size to minimize the discomfort caused by precipitation. Because it requires special equipment to obtain a suspension of lime, semi-solid method using the scrubber also requires a significant amount of equipment, and the cleaning process gas remains the>Semi-solid method using a scrubber is however preferred as contained in gases pollutants in the environment, can be removed in the form of dry waste. The disadvantage of this method is that the process is difficult to control and the degree of absorption of sulfur is less than 90%, which is lower than when using a wet scrubber. Another disadvantage of this method is that in semi-solid method, you cannot use relatively cheap limestone, because it responds very slowly with sulfur. Instead it is necessary to apply the oxide or hydroxide of calcium, which is much more expensive. In large thermal stations costs absorbent very significant.It was proposed to introduce limestone directly on stage combustion or gasification. As a result, the limestone is made red-hot with the formation of calcium oxide by the following reaction:
CaCO3__ CaO+CO2< / BR>The resulting calcium oxide may further react directly into the combustion chamber C formed here by sulfur oxides. The reaction proceeds according to the following scheme:
CaO+SO2+1/2 O2__ CaSO4< / BR>However, in the process of this reaction layers sulfate or sulfite calciu the end to end communication between gray and lime. Thus, the lime reacts completely, and therefore is not used optimally. The degree of absorption of sulfur is also influenced by many other parameters, such as molar ratio Ca/S, temperature and contact time with the bleach.The closer to the dew point temperature reaction takes place, the higher the reactivity of alkaline compounds. The best reactivity is achieved by the fact that in the wetted particles of reactions take place in aqueous phase or fast ion interaction. At temperatures close to the dew point temperature, the particles remain hydrated, so that the reactivity is also stored at the required level for a long time. Hydration of the particles is preferably maintained at such a high level that the water was surrounded by particles and can penetrate them. With the penetration of water into the particles of lime deposited on them a layer of sulfate or sulfite is destroyed, exposing new reactive surface lime. Sulfur dioxide contained in the gases dissolved in the water surrounding the particles, and interacts with the calcium compounds in the liquid phase.In the patent Finland 78401 describes the way in which the sulfur dioxide contained in the can be separated from the flue gases. Flue gases are directed into the lower part of the vertical long contact reactor. Then separately introduced into the reactor lime in powder form and water, resulting in the absorption of sulfur lime. The suspension formed flue gases discharged from the upper part of the reactor flow type and send forth on the operation of the dust. Due to the separate introduction into the reactor powdered lime and water, eliminating the need for preparation, post-processing and dispersion of a water suspension. According to the description, this method, when used to absorb sulfur oxide calcium, reduces the sulfur content of approximately 80% when the molar ratio Ca/S= 1,56, and approximately 90% when the molar ratio Ca/S=2,22. The absorption of sulfur oxide 98% is not achieved until the molar relationship of the Ca/S=4. In this way the temperature of the flue gases is also impossible to reduce to the optimal temperature close to the dew point, because otherwise the solids contained in the suspension flue gas will form layers on the walls of the tubes and other equipment, lifting, thus, the problem of cleaning from dust.In the European patent 0104335 lead another two-phase the keys the dry reagent, but on second serves water or an aqueous solution, to which is added the dissolved reagent. In the first phase on the surface of the particle reagent is formed inactive layer. This layer slows down or inhibits the reaction between the reagent and, for example, by sulphur dioxide. By adding water to the second stage reagent reactivated. Thus, the reagent is used more fully. Gas temperature is allowed to drop to the level at which it always remains above the dew point, for example, 105oC. In a specified way also you cannot lower the gas temperature to a temperature close to the dew point, since all the water-wetted particles, which may be formed, will lead to difficulties in long process of time, even though the reactivity at lower temperatures will be significantly higher. In accordance with the specified method, the required amount of reagent can be reduced by recycling the cooled material containing a reagent, which is separated from the gas at the next stage, and then regenerated by grinding or in any other way. The disadvantage of this method is that you must use separate equipment is second gas cleaning system, in which lime is added to the flue gas in the boiler, and then react with flue gases in the reactor. Lime, which is partially reacted with polluting substances contained in the flue gases, is separated from the gases by the filter in the upper part of the reactor. Separated from the gases in this way the dry lime collect and grind, but the notion is treated with superheated steam to increase the reactivity of dry lime, after which lime again return into the gas stream at the inlet of the reactor. Processing stage lime dry steam flows from 2 to 24 h, i.e., is a long process and requires significant energy consumption.The aim of the present invention is an improved method of purification of waste gases containing, in particular, compounds of sulfur, chlorine and fluorine, or other transform into a liquid state of the connection.Another objective of the present invention is a method in which, for example, can be achieved a significant reduction in the sulfur content, without the need to increase the amount of reagent used.Another objective of the present invention is a method in which the gas to be cleaned may get damp in the UP>oC, however, this method allows you to remove dry particles separated from the gases in the reactor irrigation.The above objectives are achieved by the fact that, in accordance with the method of the present invention, below the level of the input gas in the lower part of the reactor irrigation is supported by a layer of slag of such thickness that the slag formed from the particles separated from the gas capable of homogentisate wet slag particles and water drops falling down from the top of the reactor irrigation.In the layer of slag is mainly a mechanical mixer, such as mixer blade of the type for mixing and abrasion of the resulting pieces of the particles so that the average temperature and moisture content in the slag layer. The purpose of this activity is to maintain the layer of slag in such a dry state, so that the slag could be extracted from the reactor irrigation pneumatic method. The volume of the slag layer is maintained in the lower part of the reactor irrigation, for example, by regulating the quantity of recovered slag. The amount of slag should preferably be at least 50 kg per 1 cub. m/s of the injected gas. In practice, when using a reactor irrigation with relatively direct domobrani form the slag layer should be thicker. It was found that a prerequisite for the effective functioning of the mixer blade type with a horizontal arrangement is that the level of the slag preferably has been above the shaft of the mixer. On the other hand, the slag layer should not be thicker than is necessary for the effective functioning of the mixer in the upper part of the layer of slag, and it should not hinder the mixer to throw the particles of the layer of slag in the gas space above it. The layer of slag must not be above the level of the input gas.The hot gas entering the reactor, can also serve as a drying gas, and he comes into contact with the wetted particles of slag and pieces of formed particles, which are sent down from the zone of irrigation. Particles of slag from the bottom of the reactor are fond of rising up the drying gas and again fall into the area of irrigation, with the aim to activate more unreacted reagent or absorbent contained in the slag. In the reactor irrigation particles are separated from the gas by means of a filter and then returned to the bottom of the reactor. Thus, in the reactor irrigation creates an internal circulation of the particles of reagent or absorbent, and it padicotm filter, electrical filter or other equivalent type of separator. Particles removed from the filter, either periodically or continuously, for example, jet washing, backwashing or shaking, and the particles fall down into the reactor irrigation in the form of individual particles or in the form of educated their pieces.At least part of the particles stick to each other in the irrigation zone or on the filter with the formation of large agglomerates, which fall through the irrigation zone in the lower part of the reactor, while a separate small particles are easily carried away, rising gas and removed from the area of irrigation in the upper part of the reactor. Larger pieces of formed particles, and wet heavy particles are dried and crushing into smaller particles using a mixer as soon as they reach the layer of slag at the bottom of the reactor.Thorough mixing of the particles of the blades of the mixer has a positive impact, alignment, distribution of heat and moisture in the layer of slag, for homogenizing the material of the slag. Since the particles are crushed, their active surface is increased and at least part of them rises to the vortex motion in the upper layers of slag and is reactivated and acquire the ability to re-absorb sulfur in the reaction zone. It was found that the mixing, which is mechanical or equivalent powerful mixer, plays a significant role in increasing the capacity of the reactor irrigation. Mixing solves the following tasks:
- serves as means for supplying particles of slag, moving them from different parts of the bottom node of the reactor to the discharge hole,
- homogenized particles of slag, stirring them to a form suitable for air travel,
grind wet and dry pieces of slag to small particles.Dry particles of slag which fall down in the process of cleaning the filter or formed by other method of separation from flue gas at the inlet of the reactor, serve as an effective dewatering means for wet slag and drops of water falling from the zone of irrigation. The mixer mixes the wet and dry materials, and achieved the above homogenization.The mixer also promotes mixing of the particles in the upper layers of slag or buffer layer of slag, while the hot gas (flue gas) is supplied into the lower part of the reactor, carries them up, creating internal circulation of the slag in the reactor. This contributes to the intensification of the process of energy transfer, you contact time, the density of the suspension, the molar ratio Ca/S and the total area of the surface of the lime particles in the reactor zone, thus reducing the need for fresh reagent. In accordance with the invention, the average density of particles is maintained by the internal circulation in the reactor irrigation, while it is obviously higher than the density of the particles in the gas which is introduced into the reactor. Internal circulation can be controlled by adjusting the flow rate of particles rising to the surface of the layer of slag. The location of the pipeline gas supply also has an impact on recycling. The smaller the distance from the input gas stream to the surface of the layer of slag, the greater the number of particles picked up by the gas stream and climbs up with him.Part of the particles is preferably withdrawn from the reactor through the discharge hole located at the bottom of the reactor irrigation below the drying zone. Part of the discharged particles can be, if necessary, returned to the reactor irrigation. Thus, it is possible to carry out also and external circulation of particles outside of the reactor irrigation. Particles outside of the reactor can be processed in order, for example, regenerating a certain amount of reage ruhamah from the bottom of the reactor, for example, by removing excess substance in excess of the level through the discharge opening and further through the pipeline. The volume of the slag layer can also be adjusted using flow meters that control the flow of matter through the discharge opening or duct for removal of slag.External circulation in the reactor irrigation can be accomplished by connecting the filter or equivalent device for separating particles, which are fully or partially located outside of the reactor, with the upper part of the reactor irrigation. In such a filter or separator reacted and unreacted particles of the adsorbent are separated from the gases, and at least part of the particles directly back to the bottom of the reactor irrigation, preferably in the area of drying. Particles can be removed from the filter as continuously and periodically, and return them to the bottom of the reactor irrigation. Part of the substances separated by the separator, it is possible to completely withdraw from the system.In accordance with the method according to the invention, it is possible to lower the average temperature of the gases in the reactor irrigation to a level that is approximately 0-20oC, mostly 0-10oC, different is senecaut because of too moist particles in the upper and lower zones of the reactor. Particles which are wetted in the area of irrigation and falling down, dried in the drying zone with a stream of hot gas, not causing any problems at the bottom of the reactor. Thanks to the recycling of the difference in temperature and humidity minor also and above zone irrigation at different points in the cross section of the reactor. This eliminates the local problems caused by wetted particles or drops of water.In relation to the preferred embodiment of the invention, the layers formed hydrated particles on the walls of the reactor irrigation, can be removed using the schema in which at least part of the gas flowing in the irrigation zone, is directed into the reactor irrigation in the form of gas flow in the jacket of the reactor, so that the gases directly or indirectly heated wall. The gas enters the reactor through pipes located, for example, in the walls, while the hot gas passing through the pipes, prevents the cooling of the walls and, thus, the formation of deposits on the walls. Gases can also be entered directly into the reactor and send them down along the walls, i.e. protecting them. As a consequence, the wetted particles are either provided from the walls or they are dried by passing through the gas flow is through the circular hole in the wall.The process of removal of sediment from the walls can also be intensified by shaking or by making the walls of flexible material, while the pressure changes that typically occur in the system that will shake your walls, causing precipitation to fall down.In very large reactors, the gas can enter into the inner part of zone irrigation to create a more uniform distribution of the gas in the reactor. The gas can then be applied, for example, through a system of nozzles or slits, located on the pipeline in the middle part of the reactor. The gas can also be served in the reactor with several levels.Hot gas which enters the lower part of the reactor plays an important role, as it performs tasks such as, for example,
- the transfer of energy to dry the wet slag and water droplets;
- transport of particles of slag, vzvihrennyh mixer, back in the irrigation zone that creates, thus, the internal circulation of the slag in the reactor; and
- maintaining the walls of the reactor in a heated state, which reduces the probability of formation of precipitation on the walls.Irrigation zone is created by filing jets of water or steam in the upper or middle part of the reactor irrigation. Water please. Water or steam jets are directed so that was evenly covered as much as possible, the gas stream.The irrigation zone of the reactor preferably irrigation equip directed down the nozzles for supplying water or steam located, for example, structural elements that are horizontally inside the reactor.A filter located in the upper part of the reactor irrigation is mainly fabric filter such as a bag filter or the filter cassette type, or an electric filter, or some other equivalent type of filter, from which the particles are returned to the bottom of the reactor by shaking or reverse purge filter.The lower part of the reactor is preferably provided with a mechanical mixer, which mixes the solids collected in the bottom of the reactor. Mixing solids intensifies the process of alignment of the humidity and temperature of the particles, and the particles that are still wet, drained, coming into contact with more dry and hot particles. At the same time, the mixer destroys pieces of formed particles of slag, and facilitates their movement in a ve is the W inner circulation of the particles in the reactor. The rotation speed of the mixer is adjustable, which allows in combination with the gas stream entering the mixing zone, to perform in a wide range of regulation of the process of circulation of particles.The lower part of the reactor irrigation supply also devices for discharging particles from the reactor. Particles are mainly removed by means of the mixer described above. The blades of the mixer can be directed at an angle so that they will gradually push the particles to one end of the lower part of the reactor where the particles can be removed in a dry state through the appropriate gate. They also can be uploaded to a separate boot auger or discharge conveyor. Particles are mainly removed from the reactor in such a dry state, that they then can be transported, for example, pneumatically.The discharge opening must be located so that the mixer was created stock slag, while the volume (height) of the stock of the slag depends on the size of the mixer. For example, if you use the mixer blade type with horizontal shaft arrangement, the level of the slag is preferably equal to the height of the shaft. However, the level of the slag should not exceed the level at which the mixer is IPA, the effective height of 1-4 times the diameter of the mixer. The diameter of the mixer is approximately twice the length of the blade.In addition to the mixer blade type with horizontal shaft arrangement, it is possible to use another type mixers. In a cylindrical reactor, for example, you can apply vertical mixers or jet mixers based on local mixing, in which the effect of mixing creates water vapor or air.If necessary, the lower part of the reactor irrigation can be provided as a separate download sites reagent or absorbent. Removal of harmful substances from gases at one stage in the reactor irrigation can serve several different reagents.The device of the present invention provide, inter alia, the following advantages over known:
Several operations, such as the absorption of sulfur, wetting reagent, separation and drying of the particles, can be carried out in one apparatus. Irrigation gas can be carried out in the same place as the separation of slag, however, for such a process does not require either a separate device or separate reactors.In accordance with the present invention, it is possible to organize the ku filter directly installed inside the reactor, and without the need for special piping, i.e., avoids the problem of deposition of the layers on the walls of the specified gas in the process gas, which becomes humid, with the temperature close to the dew point temperature. The possibility of conducting the process at a temperature close to the dew point temperature, leads to highly efficient absorption of secretions SO2, SO3HCl and HF.Internal circulation of the particles through the zone irrigation reduces the consumption of the reagent or absorbent. Given this way the residence time of the adsorbent in the reactor becomes longer, mostly 2-10 times more, compared with the known flow type reactors.In this apparatus separates the slag containing small particles. Slag and consumed the absorbent material can be dried in the usual way. Use only one system removal and processing of slag. Dry the slag and the absorbent material can be transported by the pneumatic method.In previously known methods, the almost complete absorption of sulfur was provided under irrigation gases containing sulfur dioxide, only if the content of sulfur dioxide in the input gas was not more than 40 ppm.exceeds 100 ppm.The method is very simple.In accordance with the present invention, and simultaneously the optimal way to use the three main factors that have a positive effect on the reaction taking place during absorption:
- cooling the gas to a temperature level close to the temperature of the dew point, to ensure the flow of fast reactions;
- high molar ratio Ca/S in the reactor zone; and
- large contact time for optimal use of the absorbent.Fig. 1 is a schematic description of a preferred apparatus for implementing the method according to the present invention; Fig. 2 and 3 are schematic description of the two other devices for implementing the method of the present invention; and Fig. 4 shows the dependence of the degree of absorption of sulfur dioxide from the molar relationship of the Ca/S in the implementation of the method according to the present invention.In Fig. 1 shows the reactor irrigation 10, provided with ports for gas inlet 12 and 14, a pipeline for gas outlet 16 and the pipe 18 for discharging particles separated from the gas. The reactor irrigation is also equipped with nozzles 20 above the insertion openings of the gas for injection of water or steam in re the.The reactor irrigation of the present invention can be installed in the pipe flue gases after the combustion chamber or the grate of the furnace, the furnace chamber using liquid fuel or combustion chamber fluidized bed, such as the reactor of the circulating fluidized bed, the reactor irrigation is mainly after the boiler. Before entering the reactor irrigation flue gases are cooled to a temperature of not more than 300oC, mainly to a temperature of less than 150oC. removal from flue gases of sulfur oxide absorbent such as limestone, is fed into the combustion chamber or reactor with a fluidized bed or after them. The absorbent material at least partially made red-hot by the hot flue gas to form calcium oxide, which binds sulfur as sulfate or calcium sulfite. With regard to the lime/sulphur, equal to 1.5 and 2.1, in the reactor of the circulating fluidized bed is provided by the absorption of sulfur from about 80 to 95%. In digester irrigation flue gas still contains sulfur and unreacted lime. An important problem to be solved reactor irrigation, in accordance with the present invention, is activated lime or In the apparatus shown in Fig. 1, flue gases containing sulfur, is directed through the pipe 24 into the reactor irrigation. Before entering the flue gas in the reactor is divided into two separate exhaust gas flow in the pipes 26 and 28. Flue gas through the pipeline 26 is directed into the reactor at approximately the same level as the nozzle for the water supply. The flow of flue gas through the pipeline 28 serves substantially lower.Thus, a single stream of flue gas fed into the reactor irrigation approximately at the same level, which are nozzles for the supply of water is above or below or on the same level as the nozzle for the water supply. An important circumstance is that the gas entering the reactor is well mixed with the injected water. Both gas and water is preferably fed into the reactor in the form of downward flow, which is a short distance from the inlet turns up. Thus, the inlet for gas supply and nozzles for water supply are located in the area of irrigation, and provides good hydration.Water spray form the irrigation zone 30 of the reactor irrigation. In this zone irrigation flue gases humidified and cooled to the temperature, as can the temperature of the dew point. In this zone irrigation particles of lime wetted, while sulfur is absorbed by the particles, and in the aqueous phase can proceed faster ionic reaction between sulphur and calcium.The water is preferably fed through the nozzles, which form small droplets, which is mainly a size less than 100 microns, and which is directed at a large angle, so well overlaps the cross-section of the reactor and the gas flow. The water is directed down. Irrigation zone covers a vertical zone of the reactor, which is approximately equal to the hydraulic diameter of the reactor.In the method of the invention, shown in Fig. 1, the flue gas is fed into the reactor in the form of gas-shirts. Pipeline 26, the gas first enters the annular pipe 32 surrounding the reactor. Of an annular pipe gases are one or more directed down the tubes 36, limited by walls 34 of the reactor. The reactor has a double wall, so that between the walls 34 and 38 is formed tube 36 to enter the flue gas. The tubes 36 flue gas is directed through the holes 12 in the irrigation zone 30 of the reactor.Similarly, gas from the lower pipe 28 serves in a circular pipe 42 surrounding the reactor, and then n the second part, i.e. the zone of drying or mixing 40 reactor.The gas in the reactor irrigation control, for example, the knobs 27 and 29, are placed in the pipes 26 and 28. The input gas is also controlled by changing the width of the slit 48 of the tube 46.Gases rise from the zone of drying up, drying up thus particles that fall down from the filter and the area of irrigation. The flow of drying gas is automatically regulate devices 47 and 49, depending on the gas temperature in the lower part of the reactor or, depending on the temperature of the particles, which are to be unloaded.The lower part of the reactor provided with a mechanical mixer 50. In the method of the invention, shown in Fig. 1, use two mixer located at the bottom of the reactor and provided with blades 52. Mixers break up clumps of particles falling to the bottom of the reactor. At the same time they equalize the temperature and humidity of the particles. Mixers mainly operate in such a way that they "throw out" a portion of the particles from the bottom of the layer of slag up in the gas space of the drying zone, where the rising stream of hot gas carries the particles through the irrigation zone, possibly up to the top of the reactor. The blades of the MMU the end of the lower part of the reactor, in which is located a pipe 18 for discharging particles. Particles gradually flow through the limiting plate (not shown) in the pipeline for discharge. Thus, in the reactor are continuously being "buffer" of particles, which is balanced temperature and humidity drop-down particles.In Fig. 2 shows the reactor irrigation 10 similar to that shown in Fig. 1, except that the gas is fed into the lower part of the reactor by pipe 54 is located inside the reactor. The pipeline is equipped with pointing downwards nozzles 56 through which the gas is initially directed downward in the direction of the particles collected in the lower part of the reactor, and then moves upward. Thus, with the help of gas is achieved by the additional mixing of the particles in the lower part of the reactor.In the reactor shown in Fig. 2, the amount of water supplied to the irrigation zone, regulating device 21, depending on the gas temperature in the upper part of the reactor. To ensure uniform irrigation gas reactor irrigation can be equipped with nozzles for water supply, located at different levels.The reactors shown in Fig. 1 and 2, have cameras equipped with standard PN is p, in which the filter 60 is installed immediately behind the jet chamber. The specified path in the reactor in addition to the internal circulation of the particles is also created and the external circulation of the particles. Some of the particles, hydrated in the irrigation zone 30, are separated from the gas by yourself and fall under their own weight down in the drying zone, where they fall under the influence of the drying gas. After drying the particles rise up again, picked up by the gases, supporting, thus, internal circulation. Part of the humidified particles entrained with the gas flow in the upper part of the reactor to the filter 60 and is returned to the drying zone through the pipeline 40. If necessary, the particles can be excluded from the circulation through the outlet 64, which is covered by the valve 66.In Fig. 3 the pipes 26 and 28 to the gas supply can be connected with different stages of the combustion process, for example, so that the gas supplied to the reactor through the pipe 26 will be more chilled than the gas supplied through the pipe 28, and the pipeline can be delivered more hot gas, which is used in the drying process.Compared to known methods of the present invention provide which is confirmed by the following test results, in which used coal and limestone.Example. When testing used the device depicted in Fig. 1. In the reactor irrigation serves flue gases with a temperature of 870oC coming from the reactor with a circulating fluidized bed, in which the injected limestone in a molar ratio Ca/S, equal to 1.41 is 2.33. The estimated content of sulphur dioxide in the flue gas ranges from 860 to 960 ppm. Sulfur contained in the flue gases reacts already in the reactor with circulating pseudoainhum layer in such a way that the content of sulfur dioxide in the flue gas entering the reactor irrigation ranged from approximately 60 to 201 ppm. Gases are supplied into the reactor, having a temperature of from about 139 to 160oC. the Calculated value of the dew point temperature of the gases in the reactor irrigation is approximately 54oC.The test results presented in the table.The test results clearly indicate that in the method according to the present invention the absorption of sulfur is almost full even at low molar relationship Ca/S if the final reactions take place at a temperature close to the dew point temperature, t is even at the highest temperatures i.e., differ by 10-30oC of the dew point temperature, and with less consumption of lime than in the known methods.According to the data given in the literature, in known reactors irrigation achieved the degree of absorption of sulfur dioxide, 90%, when the molar ratio Ca/S=2,22. Approximately 98% absorption of sulfur dioxide is not reached, up to a molar relationship of Ca/S=4.In Fig. 4 shows the dependence of the degree of absorption of sulfur dioxide from the molar relationship of the Ca/S achieved in the above tests, when using the method according to the present invention. For comparison, shows the dependence of the degree of absorption of sulfur dioxide from the molar relationship of the Ca/S when testing, in which the reactor irrigation was absent.Thus, the present invention allows to integrate different stages of several different processes:
Reactor irrigation, which is located below the cassette filters or similar devices for separating particles. Through located in this space system injectors injected water for the hydration of slag particles of the adsorbent and for lowering the temperature of the flue gas to a temperature close to the pace of the filter, which is purified by countercurrent principle, pulse pressure, backwashing or shaking.- Joint device for mixing and movement of the slag and absorbent, located, for example, in the collection bin at the bottom of the reactor. A device for mixing mainly rotates at such a high speed that it breaks the precipitation in the wet state are falling from the walls and filter and being drained by a stream of hot gas.- Circulation of slag and absorbent, which is created by blowing entering the reactor flue gas through its lower part. The gas can be fed into the reactor from under the mixers so that the gas causes fluidization of the mass of particles accumulated at the bottom of the reactor. Gas flowing into the reactor from its bottom part, together with the main flow coming from the side walls, dries damp pieces formed by particles falling from the top of the reactor irrigation. Gases carry away part of the particles back into the irrigation zone, which leads to internal circulation of the particles in the reactor irrigation. 1. The method of purification of gases formed during combustion, gasification or chemical prozora, comprising adding to the gases before or after the process of the reagent and/or absorbent interacting with contained in the gases substances polluting the environment, the separation of gases containing reagent and/or absorbent, two separate gas flow, after which the first gas stream is introduced into the drying zone, located in the lower part of the reactor irrigation, the second gas stream is injected into the irrigation zone further up in the reactor irrigation for ovlastenja suspension of gas and reagent and/or absorbent of water and/or steam, characterized in that the particles of the slag is separated from the gas in the reactor irrigation, layer separated particles of slag support below the level of the input at the bottom of the reactor irrigation, separated wet slag particles and water drops falling down from the top of the reactor irrigation, mixed with particles of slag in the slag layer for homogenization temperature and humidity of the layer of slag.2. The method according to p. 1, characterized in that the particles of the slag is separated from the gas filter and the separated particles of slag are separated intermittently from the filter and fall in the irrigation zone and/or in the lower part of the reactor irrigation.3. The method according to p. 1, characterized in that the wet particles falling down from the zone of irrigation in contact with Gaudiya fact, what fraction of the particles that have accumulated at the bottom of the reactor irrigation, fond of gas introduced into the space below the zone of wetting.5. The method according to p. 1, characterized in that the wet particles and water droplets are mixed with the slag layer with the help of a mixer located in the layer of slag.6. The method according to p. 5, characterized in that the mixer breaks up large pieces of formed particles in the layer of slag.7. The method according to p. 1, characterized in that one or more at least partially directed downward jets of gas introduced into the space below the zone of wetting, destroys pieces of particles accumulated at the bottom of the reactor, and mixes the particles.8. The method according to p. 1, characterized in that the particles discharged from the bottom of the reactor irrigation.9. The method according to p. 8, characterized in that a part of particles discharged from the bottom of the reactor irrigation recycle to the reactor irrigation.10. The method according to p. 9, characterized in that the particles prior to their recycling moisturize outside of the reactor irrigation.11. The method according to p. 1, characterized in that the gases are cooled in the reactor irrigation to a temperature of about 0 20oWith greater than the dew point.13. The method according to p. 1, characterized in that the number of the layer of slag is at least 50 KGM3/with the input gas.14. The method according to p. 1, characterized in that the thickness of the layer of slag is at least 25 cm16. The method according to p. 1, characterized in that the layer of slag is subjected to mechanical treatment, the layer of slag is supported such that it extends only to work within the means of mechanical processing.16. The method according to p. 1, characterized in that at least part of the gas, which must be entered in the irrigation zone, enters the reactor irrigation in the form of a flow in the jacket of the reactor so that the gas flows in the irrigation zone through tubing located in the walls of the reactor irrigation and/or along the walls of the reactor irrigation in the form of downward flow, while the flow in the jacket of the reactor prevents the cooling of the walls and the deposition of the layer of solids on the walls.17. The method according to p. 1, characterized in that at least part of the gas which must be introduced into the drying zone, enters the reactor irrigation in the form of a flow in the jacket of the reactor so that the gas enters the drying zone through tubing located in the walls of the reactor irrigation, thus preventing Alpaslan down jets.19. The method according to p. 1, wherein water or steam is served in different parts of the irrigation area in the reactor.20. The method according to p. 1, characterized in that the recycling or internal circulation of the particles in the reactor irrigation is controlled by regulating the flow paged slag.
FIELD: heat technology.
SUBSTANCE: invention relates to technology for treatment of smoke gases from sulfur dioxide. Method for treatment of smoke gases from sulfur dioxide involves passing smoke gases through countercurrent scrubber with absorption liquid based on ammonia aqueous solution for preparing ammonium sulfite followed by oxidation of ammonium sulfite to ammonium sulfate. Then one part of absorption solution removing after oxidation is mixed with fresh ammonium aqueous solution and fed to treatment of smoke gases and another part is fed to utilization. Oxidation is carried out with smoke gases oxygen in indicated scrubber in addition initiating agent for oxidation to absorption liquid as azocompounds. Invention provides simplifying the process and to reduce time for accumulation of ammonium sulfite by 1.8-2.0-fold.
EFFECT: improved method for treatment.
FIELD: method of reduction of SOx emissions.
SUBSTANCE: proposed method includes preheating and roasting of raw material mixture in plant including cyclone preheater and roasting furnace. Catalyst in form of chloride and/or mixture of several chlorides is introduced into preheater at stage of highest cyclone or cyclone preceding relative to highest one. Catalyst is directed downward to roasting furnace through preheater; definite amount of waste gases containing vaporous catalyst is extracted from roasting furnace. Flow of waste gases thus extracted is cooled for converting the catalyst to solid state. Solid agent is separated from cooled flow of waste gases and some part of separated solid agent containing catalyst is fed to preheater by recycle, thus considerably reducing the SOx emissions. Chloride and/or mixture of chlorides activate catalytically reaction of SO2 with CaO forming CaSO3 and additionally activate reaction of SO2 with CaCO3 forming CaSO3 and CO2. Thus, CaCO3 is present in considerable amount and SO2 may be reduced without additional reagents.
EFFECT: enhanced efficiency.
8 cl, 1 dwg
FIELD: method of desulfurization of waste gases; power engineering, chemical industry, ferrous and non-ferrous metallurgy.
SUBSTANCE: proposed method includes heterogeneous-catalytic oxidation of sulfur dioxide contained in flue gases and absorption of sulfuric anhydride formed during this procedure by water. Used as catalyst are ferrospinels prepared on base of manganese-zinc powder in form of thin plates which are constantly crushed directly in zone of oxidation of SO2 and SO3 in aqueous medium continuously generating freshly formed catalytically active surfaces. Process is performed under normal conditions: room temperature and atmospheric pressure.
EFFECT: enhanced efficiency.
FIELD: chemical industry; methods of neutralization and a utilization of the aggressive chemical compounds.
SUBSTANCE: the invention is pertaining to the field of neutralization and a utilization of the aggressive chemical compounds, in particular, the saturated with the anhydrides acid-containing compounds and wastes. The neutralization is applied to the smoke mixture containing the sulfuric anhydride and chlorosulfonic acid, or the oxidizing agent of the rocket propellant based on of the nitric acid containing a dimer of the nitrogen dioxide. For neutralization use the hydrolyzed dispersible aluminosilicates based of the natural clays selected from: hydromicaceous Cambrian clay, montmorillonite clay, kaolinite clay or on the basis of their mixtures. At that the hydrolyzed dispersible aluminosilicates, which are taken at least in equal shares with an aggressive chemical compound, are prepared at the following ratio of components (in mass shares): a dry substance - 1.0-2.5, water - 1.0. The invention allows to neutralize the aggressive wastes and to produce the useful product with the sorption activity.
EFFECT: the invention ensures neutralization of the aggressive wastes and production of the useful product with the sorption activity.
3 cl, 2 ex, 6 tbl
FIELD: purification of gases.
SUBSTANCE: method comprises absorbing sulfur dioxide by means of a lime suspension, crystallization, and removing slime. The gas is cooled before absorbing up to the dew point by water evaporating. The ratio of the volume of water to that of the gas should be 0.08-0.12 l/m3. The water temperature exceeds that of the dew point by 10°C of the cooled gas. The gas is absorbed by the suspension made of droplets supplied perpendicular to the gas flow.
EFFECT: enhanced quality of purification.
1 cl, 1 dwg, 1 tbl