The method of wet cleaning device for removing sulfur oxides from combustion products

 

(57) Abstract:

Use. The invention relates to the purification of flue gases from sulfur oxides. Essence: the described method of removing sulfur oxides (SOxfrom flue gases water slurries of limestone and device for its implementation. In one-way open tower countercurrent scrubbers for limestone wet scrubbing gases, the flow rate of exhaust flow significantly increase, while the value of W/G and the length of stay in the reaction vessel is reduced. These advantages stem from the use of drop entrainment improved design, character placement of the nozzles and the spacing between them, as well as the use of hydrocyclones for separation from gypsum obtained as a by-product, and return to process smaller particles of limestone. Limestone is crushed to very fine particles, for example, with dimensions of approximately 8 μm or less when the amount is more than 99 wt.% particles less than 44 microns, and add in the slurry for washing gases, which enter into contact with the exhaust stream containing the SOx. The reactivity of the slurry for washing gases support even mogo ratio between calcium and sulfur-containing compounds above about 1.3:1 and simultaneously low as chlorides, and directionspublic commodity materials. The cyclone removes large particles of calcium sulfate and allows to obtain a recycle stream of finely dispersed calcium carbonate and directionspanel solid material as needed washed to maintain the target low chloride content and directionspublic solid materials. The invention provides greater efficiency and economy in terms of capital and operating costs. 8 C. and 24 C.p. f-crystals, 5 Il.

The invention relates to the improvements that provide effective removal of sulfur oxides (SOxfrom flue gases and reducing at the same time, capital and operating costs, and more precisely to a method of wet limestone scrubber and to the device for its implementation.

The combustion of carbonaceous materials containing significant amounts of sulfur, including fossil fuels and waste, are under the strict control of governments worldwide. The combustion of these materials leads to the connection of free radicals sulfur and oxygen at elevated temperatures causing the formation of various oxides of sulfur, which is richest sulfur, discharged into the atmosphere in order to mitigate the problems associated with acid rain.

To reduce emissions of SOxthe atmosphere used a variety of methods. Among them there are methods of removing sulfur from the fuel before combustion, methods for chemical binding of the sulfur in the combustion process and methods of removing sulfur oxides from flue gases. The methods of processing flue gases to remove SOxinclude wet and dry cleaning. The wet gas cleaning technology is well developed and effective, but it requires cumbersome equipment and the associated costs.

In a number of different installations of the technology of wet cleaning of flue gases to remove SOxbased on the contacting of gas and liquid between them. Among the most common plants can be called one - and two-way-flow tower with nozzles and towers, which are provided as direct-flow and counter-flow section.

The most simple in design and technology are one-way open tower system in which to interact with SOxuse calcium carbonate. These systems are often preferred as it is, however, their inherent simplicity and reliability in some cases eroded their large size. Due to the fact that in order to improve contact between the waste gas and the washing liquid in them does not use any plates or nozzles, the height of the towers, usually very large, so in order to ensure good communication typically use multiple levels of spray nozzles.

In open towers with the spray nozzles of the ability of a liquid for washing the gases to absorb SOxof the gas depends on the availability contained in a liquid base. The most effective in terms of value, the basis for scrubbers is widely regarded as calcium carbonate. Unfortunately, with increasing alkalinity of a liquid for washing the gases the solubility of calcium carbonate is usually reduced. Tower with nozzles and plates improve the absorption due to a longer retention of calcium carbonate in the zone of contact of the gas with the liquid, thereby creating a mechanism for more efficient dissolution and, as a result, more efficient use of the liquid for washing the gases. On the other hand, in order to ensure the maximum possible duration of contact open tower with nozzles, as a rule, the design is relatively higher, CIMI gases in the tower.

Thus, there is a need to improve the wet cleaning is contained SOxin flue gases in one-way open towers processing of calcium carbonate by increasing process efficiency and profitability while reducing the total required overall dimensions of the tower, the improvement in the utilization of calcium carbonate, maintaining the high reliability, reduce energy costs and achieve high performance in combination with a significant reduction in the percentage of SOx.

There is a need to improve wet cleaning is contained SOxin flue gases in one-way open towers processing of calcium carbonate by increasing the reactivity of the slurry for washing gases without the use of chemical additives.

Design and operation of single counterflow towers with nozzles that apply limestone, described Rader and Bakke in the work of Incorporating Full-Scale Experience Into Advanced Limestone Wet FGD Designs presented on IGCI Forum '91, September 12, 1991, Washington, D.C. (originally Industrial Gas Cleaning Institute, now the Institute of Clean Air Companies, Washington, D.C.). Open tower with the Oia gas to liquid) of simple construction and high reliability. They are primarily used in power plants that use solid fuel, where the selection of chlorides creates a number of problems, including a reduced reactivity of the slurry for washing gases and intensive corrosion of the internal equipment of the scrubber. Another factor contributing to the use of towers with nozzles, is their inherent low pressure drop and, consequently, energy saving exhaust devices.

It was suggested to use different reagents, but the most preferred are those which are effective in small quantities and which can be purchased at a low price, to store and transport with a minimum of manipulation. Therefore, this reagent was chosen as calcium carbonate (commercially available in several varieties, including limestone), because it satisfies the specified criteria, and with the right process produces by-products that can be easily disposed of as waste in landfills or sold as gypsum.

In one-way flow of open scrubbing towers of the type described by Rader and Bakke, liquid for flushing gas on the basis of calcium carbonate expire from top to bottom, while Chechenia a number of parameters, including gas flow rate in the absorber (resulting minimum 6 and maximum 15 feet per second, i.e., from about 2 to less than 5 meters per second), indicating that this gas flow rate in the absorber has little impact on the ratio between liquid and gas (G/G), which is a key factor for both capital and operating costs. The height of the zone of contact of the spray slurry in the towers not shown, but typical values typically range from about 6 to about 15 m, which, based on experience, is considered as an important factor when designing an effective system, from which we can expect reliable removal of at least 95% of SOxfrom the exhaust flow of flue gases.

It is known that in the towers of the specified type, the ratio between the quantities of sludge and gas (W/G) can be considered as the only structural parameter that is important. W/G affects the costs associated with pumping, storage tanks and other technological and economic factors. The cost of pumping the limestone slurry is increased in proportion to the increase in the height of the tower. It is advisable to reduce the required value of W/G and the height of the towers with nozzles.x.

From prior art it is also known the use of Packed towers. Rader and Bakke emphasize that although the tower these types of possess a certain advantage, as expressed in the reduction of operational costs linked to additional risk. Nozzles or other means of mixing gas with liquid can cause or correlate and cause unwanted leakage or pressure drop, leading to downtime. It is advisable to use open BA is higher towers of known construction.

On prior art literature there are no indications funds for improvements, which in the case of a single open tower countercurrent scrubbers to reduce the content of SOxwet scrubbing limestone provide results comparable with that obtained in Packed towers, but without the use of nozzles or related problems.

In one-way flow of open scrubbing towers of this type, as discussed Rader and Bakke, sludge, washing the gases containing calcium carbonate, calcium sulfate, calcium sulfite and other directionspanel solid materials, expire from top to bottom, while containing SOxexhaust flue gas moves upward. SOxmainly SO2absorb downward flow of slurry for washing gases and collected in the reaction vessel, in which form calcium sulfite and calcium sulfate. To accelerate the formation of sulfate through the sulfite reaction tank, it is advisable to saturate with oxygen. After growing crystals of sulphate of sufficient size they are removed from the reaction vessel and is separated from the sludge. Also remove soluble impurities such as chlorides. With klonoa ability of sludge for washing gases. Indeed, these costs are influenced negatively by high concentrations of dissolved in the slurry for washing gases chlorides, which inhibit the reactivity of calcium carbonate.

It is known that the chloride content of sludge for washing gases can be reduced by using a liquid for washing. Typically, the material for flushing take from the reaction tank or out of the water separated from the gypsum recovered from the process.

For example, according to US-3995006 on the name of the Downs, etc. from graceadelica absorber removes sludge and direct it to the hydrocyclone separator for separating a stream with a high content of fine particles of calcium sulfite from the stream with a high content of relatively large particles of calcium carbonate. After the second branch of the sulfite calcium thickened as the flow is discharged into the waste. In most cases, resetting the waste of large quantities of water suppresses the accumulation of chlorides in the system. However, the discharge of a large quantity of water from both ecological and economic points of view undesirable.

In US-5215672 in the name of Rogers and others described method, similar to the way Down and others that in it to separate the unreacted carbonate Kala flue gases, apply the hydrocyclone. In this case, after separation of the stream of finely dispersed solid particles from a stream of coarse particles, rich in gypsum, water as part of the thickened small stream discharged into the waste together with at least part of the remote stuff. Although rinsing with spending parts of water sufficient to suppress accumulation of chlorides in the system, in such a scheme is removed proportionally large number of finely dispersed solid particles. The Rogers and others proposed to reset the change in the form of waste. However, from the description of the present invention it is obvious that the change of such technical acceptance on the opposite, despite washing using water to suppress chloride, allows to increase the reactivity of the system and to simplify its schema.

In hydrocyclone circuit (described Rosenberg and Koch in the work, published in the 93rd Bimonthly Report of the Stack Gas Emissions Control Coordination Center Group, July 1989 ), placed in the plant for EDC (flue gas desulfurization) in the Netherlands, similar to that described in Rogers and others , provided by the separation of the gypsum slurry from the scrubber for scrubbing gases to flow from the coarse solid particles and the stream of finely dispersed solid particles for leaching does not take away from the stream, it should be selected from any other source. Attached to the article of the technological scheme (Fig. 2) shows the selection of material for flushing of the vacuum belt filter. The water discharge at this stage of the process reduces the concentration of chlorides, but this is achieved by removing greater quantities of water than is necessary because the remote so the water is diluted with fresh portion of the source water used for washing of gypsum.

In the prior art are not described devices and methods necessary to improve reactivity in a situation with a single open tower countercurrent scrubbers to reduce the content of SOxwet limestone cleaning.

A closer technical solution to the proposed method and the device described in the article by K. R. Hegemann and others, entitled THE BISCHOFF FLUE GAS DESULFURIZATION PROCESS (presented in EPA and EPRI, who were co-sponsors of the First Combined FGD and Dry SO2Control Symposium, 25-28 October 1988). It revealed how wet limestone gas purification in which the open tower countercurrent scrubber to reduce the content of SOxin the flue gas, including the flow of flue gas from the inside of the tower aerosol of droplets of an aqueous slurry of finely ground calcium carbonate, calcium sulphate and inert solid materials and enter into contact with flue gas in countercurrent to the flue gas stream, collecting the sludge in the reaction tank after contact with flue gas, removing the slurry from the reaction tank, processing remote from the reaction tank slurry, providing a recirculation stream, rich in fine particles of calcium carbonate, and the other stream rich in particles of calcium sulfate, the introduction of fresh calcium carbonate as raw material in the system in quantities sufficient to replace the remote and not returned to the process of calcium, and calcium, which dissolved and reacted with the SOxpreoccupied with the liquid phase in the scrubber section.

A device for implementing the known method comprises a scrubbing tower, equipped with a box for entering gases, a conduit for exhaust gases and a vertical scrubbing section, directing the flow of flue gas from the bottom up through it, the group placed inside the scrubber section of the spray device that provides input to the stream of flue gas aerosol of an aqueous slurry of finely ground calcium carbonate in the tower in countercurrent to this stream, the reaction reservoirs contact with the flue gas within a vertical scrubbing section, device for feeding into the reaction vessel in the form of raw materials of calcium carbonate, feeder slurry spray, containing at least one pump connected therewith a pipe for draining slurry from the reaction tank and the feed slurry to the group of spray devices, the system maintain the quality of the sludge containing the hydrocyclone, able to separate the slurry from the reaction tank at a flow rich in small particles of calcium carbonate, and another thread with the larger particles of calcium sulfate, at least one pump and associated pipe for draining slurry from the reaction tank and the feed slurry in the cyclone, the recirculation pipe, passing from the hydrocyclone to the reaction tank and serves for the supply of the hydrocyclone recirculation flow, rich in calcium carbonate, the discharge pipe which is connected with this recirculation pipe and serves to remove a part of the recirculation flow from the recirculation pipe, and the pipe to highlight slurry of calcium sulfate, passing from the hydrocyclone and is used to remove slurry of calcium sulfate from the hydrocyclone.

However, the known method and the device has the same disadvantages as enetreset wet cleaning of flue gases, first of boilers, solid fuel, for removal of oxides of sulfur.

This problem is solved by using an improved method for wet limestone gas purification in which the open tower countercurrent scrubber to reduce the content of SOxin the flue gas, including the flow of flue gas containing SOxfrom bottom to top on the vertical scrubbing tower, the flow in the vertical scrubbing section inside the tower aerosol of droplets of an aqueous slurry of finely ground calcium carbonate, calcium sulphate and inert solid materials and enter into contact with flue gas in countercurrent to the flue gas stream, collecting the sludge in the reaction tank after contact with flue gas, removing the slurry from the reaction tank, processing remote from the reaction tank slurry, providing a recirculation stream, rich in fine particles of calcium carbonate, and the other stream rich in particles of calcium sulfate, the introduction of fresh calcium carbonate as raw material in the system in amounts sufficient to replace the remote and returned to the process of calcium, and calcium, which dissolved and proreader the SOxinjected into a vertical scrubbing tower with a flow rate of more than about 4.5 m/s, return to the process in the reaction vessel main part of the recirculation flow, rich in finely dispersed calcium carbonate.

This srednevekovoi the particle size of finely ground calcium carbonate entered as raw material, the feed should be less than about 8 microns.

The pH of the slurry when it is input in the scrubber tower strive to maintain from about 5.0 to about 6,3.

Preferably the velocity of the gas stream in the scrubber tower to support up to about 6 m/s

It is also desirable in accordance with the proposed method in the tower to place the drop entrainment in order to ensure the reduction of the number of droplets, carried away by the gas, and the change of direction of the flow of flue gases.

Using the specified drop entrainment direction of the flue gas stream is rejected at least at the 30ofrom the vertical axis of the tower, and in the direction of gas flow after the drop entrainment placed vertically mounted humaniatarian.

In one of the preferred embodiments of izobreteniya, rich fine particles of calcium carbonate, srednevekovoi diameter of approximately 6 μm or less, and the molar ratio between calcium and sulfur-containing compounds is at least 1.3, and exhaust stream, rich in relatively large particles of calcium sulfite, srednevekovoi diameter which is from about 25 to about 55 microns.

It is advisable to take cuttings from the reaction vessel after the average length of stay of less than about 8 hours.

It is also advisable at least part of the sludge in the recirculation flow to return to the reaction vessel at a molar ratio between calcium and sulfur-containing compounds of at least 1.3, when the solid content material less than 10%.

It is most expedient that the molar ratio was greater than about 1.4, and the recirculation stream contained less than 5% of the suspended solid material.

Preferably the slurry to enter the spray nozzles, which are placed on two levels with distance between them of less than about 2 m, the direction of the expiration of smeathman particles of calcium carbonate in the reaction tank to maintain from about 2 to about 6 microns, and srednevekovoi the particle size of finely ground calcium carbonate when the input is less than about 8 microns, where 99 wt.% particles less than 44 microns.

It is also desirable to ensure that the pH of the sludge in the reaction tank was from about 5.8 to about 6,3.

In another preferred embodiment of the invention the flue gas stream is served in a vertical scrubbing tower with a speed of from about 4.5 to about 6 m/s, return to the process in the reaction vessel main part of the recirculation flow, rich in finely dispersed calcium carbonate, while srednevekovoi particle size entered as raw material, finely ground calcium carbonate with the addition of fresh calcium carbonate is less than about 10 microns.

In this case, the pH of the sludge in the reaction tank support from approximately 5.0 to approximately 6,3. The pH of the slurry when it is input in the scrubber tower is from about 5.8 to about 6,3.

In this case, the sludge is removed from the reaction vessel, sent to the hydrocyclone with the receipt of the recirculation flow, rich in fine particles of calcium carbonate, srednevekovoi diameter cotterhue connections equal to at least 1.3, and removed stream rich in relatively large particles of calcium sulfite, srednevekovoi diameter which is from about 25 to about 55 microns.

At least part of the sludge in the recirculation flow back into the reaction vessel at a molar ratio between calcium and sulfur-containing compounds, equal to at least 1.3.

It is desirable that this ratio was higher than about 1.4 when the content in the recirculating stream is less than 5% of the suspended solid material.

While calcium carbonate is crushed immediately before the input as raw material in the slurry to maintain 99% of the content of the carbonate particles with a size less than 44 microns, and srednevekovoi particle size of the calcium carbonate in the reaction tank support from about 2 to about 6 microns, and srednevekovoi the particle size of finely ground calcium carbonate when its input is less than about 8 microns, where the size of 99 wt.% particles less than 44 microns.

In another preferred embodiment of the invention srednevekovoi particle diameter of calcium carbonate fed to the scrubber tower, support equal to about 6 is ENISA least 1,1, when collecting the sludge in the reaction tank pH support from approximately 5.0 to approximately 6,3, sludge is removed from the reaction vessel after the average length of stay of less than about 6 hours, processing remote from the reaction tank slurry is carried out to achieve srednevekovogo size of the fine particles of calcium carbonate less than about 6 microns and srednevekovogo particle diameter of the calcium sulfate from about 25 to about 55 microns, return to the process in the reaction vessel at least part of the recirculation flow, rich in finely dispersed calcium carbonate, the value of the molar ratio between calcium and sulfur-containing compounds in the return process part of a recirculation flow rate of at least 1,4, and fresh calcium carbonate as raw material is introduced into the system in amounts sufficient to replace the remote and unreturned in the process of calcium, and calcium, which have dissolved and reacted with the SOxpreoccupied with the liquid phase in the scrubber section, and srednevekovoi particle size of input finely ground calcium carbonate support less than about 8 microns.

In another predpochtitel injected into the scrubbing tower through spray nozzles, located on two levels, the distance between which is less than approximately 2 m, and the direction of discharge from adjacent nozzles alternately change from top to bottom and Vice versa, in the process in the reaction tank return at least part of the recirculation flow, rich in finely dispersed calcium carbonate.

In the method of reducing the content of SOxin the flue gas wet scrubbing in accordance with the invention srednevekovoi the particle size of finely ground calcium carbonate, input in the form of slurry in the scrubber tower is from about 1 to about 8 microns, and when the input of fresh calcium carbonate as raw material in the system srednevekovoi the particle size of input finely ground calcium carbonate is less than about 10 microns.

Another method of reducing the content of SOxin the flue gas wet scrubbing in accordance with the invention, the dimensions of the reaction vessel is chosen in such a way as to ensure the cooperation of SOxwith calcium carbonate to obtain crystals of calcium sulfate, srednevekovoi the diameter of the particles of which at least 2 times the size of the particles of calcium entered as raw materials, and to maintain niskin flow in accordance with the results of determination of the chloride content.

In addition, when the method of reducing the content of SOxin the flue gas according to the present invention the pH of the sludge in the reaction tank is preferably maintained from about 5.0 to about 6,3, in order to maintain a low concentration of chlorides in the sludge in the reaction tank determine the chloride content in the recirculating stream and remove a portion of the recirculation flow in accordance with the result of determination of chloride content, the molar ratio between calcium and sulfur-containing compounds in the return process part of the recirculation flow is maintained slightly greater than about 1.3, and srednevekovoi the particle size of fresh finely ground calcium carbonate in this case is less than about 10 microns.

A device for implementing the proposed method comprises a scrubbing tower, equipped with a box for entering gases, a conduit for exhaust gases and a vertical scrubbing section, directing the flow of flue gas from the bottom up through it, the group placed inside the scrubber section of the spray device that provides input to the stream of flue gas aerosol of an aqueous slurry of finely ground calcium carbonate in n is designated for the collection of sludge after a period of contact with the flue gas within a vertical scrubbing section, device for feeding into the reaction vessel in the form of raw materials of calcium carbonate, feeder slurry spray, containing at least one pump connected therewith a pipe for draining slurry from the reaction tank and the feed slurry to the group of spray devices, the system maintain the quality of the sludge containing the hydrocyclone, able to separate the slurry from the reaction tank at a flow rich in small particles of calcium carbonate, and the flow of relatively larger particles of calcium sulfate, at least one pump and associated pipe for draining slurry from the reaction tank and the feed slurry in the cyclone, the recirculation pipe, passing from the hydrocyclone to the reaction tank and serves for the supply of the hydrocyclone recirculation flow, rich in calcium carbonate, the discharge pipe which is connected with this recirculation pipe and serves to remove a part of the recirculation flow from the recirculation pipe, and leaving the hydrocyclone inlet for slurry of calcium sulfate. According to the invention the improved device is that the reaction vessel is made with dimensions that provide for STIC of which at least 2 times the size of the particles of calcium carbonate, entered as raw material, and the feeder of calcium carbonate in the reaction tank is made with a possibility of particles with srednevekovym size of less than about 10 microns.

The advantage of the invention lies in the fact that the diameter of the tower may be relatively small, due to the fact that the working speed of the gas flow passing through the spray zone of contact (if based only on cross-sectional area and neglected area of the spray headers and nozzles) shall be not less than 4.5, preferably up to 6 meters per second. Speed boosts suspendirovanie liquid in the tower, no increase its height and the use of nozzles or plates to hold the liquid in suspension, and the suspended thus the fluid is more reactive due to the increase in the time for dissolution of calcium carbonate. In other words, the obvious advantage of the invention is to increase the duration of contact of gas and solids in the tower while maintaining simplicity of design, structural design, operation and maintenance of the open tower with a significantly increase its reactivity.

The result of these enhancements is the tower, by weight and volume at approximately half of the modern open tower scrubber. The effectiveness and efficiency of the process increased, while improving the utilization of the reagent, saving, high reliability, reduce energy costs and achieve high performance while significantly reducing the percentage of SOx.

The essence and additional advantages of the present invention are described in more detail below with reference to the accompanying drawings, where:

in Fig. 1 shows schematically a variant of the method according to the invention, a wet limestone cleaning gases using one of the open tower countercurrent scrubber;

in Fig. 2 is a more detailed diagram of the scrubbing tower of the type according to Fig. 1;

in Fig. 3 is a partial side view of the layout of the spray devices located on two levels of spray tower according to Fig. 2;

in Fig. 4 is a bottom view of the spray device at two levels of spray tower type according to Fig. 2;

in Fig. 5 - axonometric image of drop entrainment in the tower according to Fig. 1 and 2.

The invention is preferably used for cleaning demotive in processes for the purification of gases with a high content of chlorides, for example, in furnaces for annealing. Although these benefits are likely to be most significant in processes of this type, it does not mean that the scope of the invention limited. You can process streams of gases formed during the combustion of carbonaceous materials of all types, including natural gas, synthesis gas, liquid fuel, bitumen and residual boiler fuel, household and industrial solid and other combustible waste, etc.

The main object of the following description of a preferred variant of the invention according to Fig. 1, which shows the work of one of the open tower countercurrent scrubber wet limestone cleaning gas to remove sulfur oxides, primarily SO2from flue gases.

Limestone is the preferred form of calcium carbonate, but if necessary it can be replaced by another form of calcium carbonate, including oyster shells, aragonite, calcite, chalk, marble, marl, and travertine. You can apply fossil material or produced in the production. In this description, the terms "calcium carbonate" and "limestone" are used interchangeably.

It should be noted that almost all pre inert materials such how free silicon dioxide, magnesium carbonate and dolomite, iron oxide, aluminum oxide, etc. In principle for the process of wet cleaning is always advisable to work with a very pure flavors of limestone, but in the practical process of wet gas cleaning constantly present some impurities, which form directionspanel solid materials. Other sources directionspublic solid materials falling within this process, is fly ash out of the collector 10 for collecting particles entrained scrubber 100.

Limestone finely milled, preferably by grinding, as described below, to achieve srednevekovogo particle diameter of approximately 10 microns or less in 99% of the content of particles smaller than 44 microns. This material is solely onkodispanser for wet cleaning of gases in an open tower with counter-current expiration flow limestone slurry. More typical particle size during grinding according to the prior art corresponds srednevekovoi diameter of 15 μm or less at a content of not more than 95% of particles with a size less than 44 microns. As another difference from the prior art, it should be noted that when Ismailism when the content of 90 wt.% (for example, of 99.5 wt.%) particles with a size less than 44 microns. The use of grinding to the specified particle size has several advantages.

In the diagram illustrating the implementation of the method according to Fig. 1, shows the flow of flue gas, in particular, waste from industrial or domestic boiler, solid fuel entering the collector 10 for collecting particles, for example, electrostatic precipitator or fabric filter, which provides practical filter captured by the flow of solid particles. Cleaned flue gas then passes through the duct 20 into the tower 100 for wet purification of gases, where he moves from the bottom up towards the flow of the aerosol aqueous slurry containing finely ground limestone, which is created within a vertical scrubbing section 110 two levels of spray devices. From this section 110, the gas passes through the exhaust duct 120. The configuration of the tower causes the flow of flue gas passing upwards through the vertical scrubbing section 110 of the flushing gas. Suspension for gas washing, falling in a vertical scrubbing section 110, collected in the reaction vessel 130. The size of the reaction vessel 130 must be suitable for interaction SO2with calcium carbonate with OBRAZOVATEL particle size of calcium carbonate, entered as raw materials.

Maintaining this difference of particle sizes simplifies the implementation of the preferred variant of the invention, which is provided by the removal of a stream of slurry from the reaction tank after the average length of stay in it for approximately 6 hours, the concentration of flow in relation to calcium carbonate (in the form of fine particles, preferred srednevekovoi diameter which is less than approximately 6 μm) and the removal of the plaster.

Vertical scrubbing section 110 contains a group of spray devices (nozzles) placed inside it. The composition of this group is designed for the input of an aerosol of an aqueous slurry of finely ground calcium carbonate in the form of a stream descending in the tower in countercurrent to the flue gas stream. The drawing shows a set of spray nozzles, which are arranged on two levels 112, 112'. Each of the nozzles 114 (Fig.2) feeds the sludge collector 116, 116' or 116". Typically, there is also a third level of the reservoirs, allowing to disable one of the levels for repair or cleaning, while the other two remain in operation.

The nozzle preferably the distance between the level alternately change from upper to lower and Vice versa. In preferred versions of the invention reduced the gap between the nozzles, reduced the number of simultaneously operating levels (preferably one to two) and increased the speed of the upward flow of the gas inside the vertical scrubbing section. Scheme movement on the tower sprayable slurry from the top down and the flow of gas from the bottom up is shown in Fig. 4.

The preferred embodiment of the nozzle is a centrifugal nozzle, which ejects the spray stream at an angle to its being in the range of from about 90 to about 140opreferably approximately 120o. One of the suitable for this purpose nozzles is a Whirljet nozzle at 300 gallons per minute supplied by the company Spraying Systems Co., Wheaton, PCs Illinois. The preferred size of the aerosol droplets is from about 100 to about 6000 microns, usually about 2000 microns, the average diameter Sauter, defined by the particle analyzer Malvern.

Each of the collectors 116 is oriented at some angle to the collector of the overlying or underlying level. In the case of using two or three levels, this angle is preferably 90o.

One of the most effective distinctive features sobrero 6-8 hours compared to 15 hours for typical cases known. This contributes to the increased dissolution rate of the fine particles of calcium carbonate and to a certain extent, the relatively high rate of deposition of calcium sulphate with the formation of particles of gypsum. The reactivity of the slurry increases, in turn, the Department of calcium sulfate from calcium carbonate and the return of calcium carbonate in the slurry in the form of very fine particles, which are quickly dissolved in the reaction tank. Reducing length of stay in the reaction vessel has a positive impact on the overall efficiency of the process, and also provides a number of advantages from the point of view of simplicity of the process, machine size and quality of the gypsum obtained as a by-product.

The feed rate of the flue gas moving along the vertical scrubbing section 110, is greater than 4.5 and preferably is approximately 6 meters per second. In the case of a single open tower scrubbers for limestone wet gas cleaning these speeds are quite high, they are preferably used in combination with other new techniques to improve the overall efficiency of the process. The scrubber tower according to the invention of the OSTs water slurry, for example, under reduced ratio W/,

The sulfur oxides in the flue gas stream is absorbed by the water phase of the slurry with the formation of bisulfite and hydrogen ions. Some bisulfite are oxidized to sulfate, releasing more hydrogen ions. As saturation drops of hydrogen ions calcium carbonate begins to dissolve with increasing speed, producing the calcium ions and bicarbonate. Finely ground calcium carbonate very effectively absorbs hydrogen ions, thereby increasing the absorptive capacity of the aqueous phase in the spray zone of the tower. For high velocities of the gas and of the adopted schemes spray created in accordance with the preferred variants of the invention have an inherent tendency to maintain the droplets of the slurry in suspension with the degree of fluidization, providing improved communication.

According Fig. 1 limestone finely pulverized in a mill 170, are classified in the cyclone 172, collected in pleuromutilins chamber 174 with bag filters and metered through the airlock 176 in the compressed air stream flowing through line 178. Grinding limestone directly before entering the scrubber and allows calcium, with particle sizes in a defined interval, without large particles, i.e., those larger than about 44 microns. Indeed, as a rule, it is possible, because dry grinding usually get particles of calcium carbonate srednevekovogo size less than about 8 microns with a content of 99% or more particles smaller than 44 microns. The exclusion of large particles of limestone introduced into the reaction vessel, is a major feature that allows you to make the reaction tank according to the invention is significantly smaller in dimensions from those currently known in the scrubbers.

In line 178 air facilitates the supply of oxygen for oxidation of sulfite and bisulfite ions to sulfate ions. The contents of this tank, it is preferable to mix conventional means which are not shown.

At the other end of the process depicted in Fig. 1, the sludge away from the reaction vessel 130 for the concentration of the reactive calcium carbonate to return to the process and reducing the amount of solid material, mainly due to the removal of the plaster. In Fig. 1 shows that the sludge away from the reaction reservoirs is of, as he quickly and efficiently separates very fine limestone particles from larger particles of calcium sulfate. Preferred srednevekovoi particle diameter of the calcium sulfate is from about 25 to about 55 microns. Separating smaller particles of limestone leads to the formation of the recirculation stream 174, rich in calcium carbonate, and the merged stream 176, rich in calcium sulphate. Preferably srednevekovoi particle size of the calcium carbonate in the reaction vessel and, consequently, in the recirculation flow 184 to maintain from about 2 to about 6 microns.

In Fig. 1 shows the preferred embodiment of the invention, in which the recycle stream after treatment in the hydrocyclone 181 concentrate in the ratio of calcium carbonate and a suitable process water in the hydrocyclone 181. Particles of calcium carbonate are preferred size are characterized by srednevekovym diameter in the range of from about 2 to about 6 microns. Srednevekovoi particle diameter of the calcium sulfate is from about 25 to about 55 microns.

The reaction vessel 130 is located below the level of the spray devices that allows you to collect the sludge in soversheni is serveware 130 acceptable for interaction SO2with calcium carbonate with the formation of gypsum crystals, srednevekovoi the diameter of which at least 2 times, preferably 5 to 10 times, greater than the particle size of calcium carbonate entered as raw materials.

Due to the difference between the particle sizes of calcium carbonate and gypsum, and the means used to separate gypsum and concentration of calcium carbonate, as described in more detail below, the concentration of solid material in the calcium carbonate can be increased by approximately 20-50% relative to the achievable previously known countercurrent scrubbers. An additional advantage of the invention lies in the fact that the sludge is characterized by a higher stoichiometric ratio between calcium and sulfur-containing compounds than in previously known systems, typically comprising at least 1.3, preferably about 1.4 or more. This system includes at least one pump 182 and associated pipe 183 to remove cuttings from the reaction vessel and the feed slurry in the cyclone.

The sulfur oxides from the flue gases is absorbed by the water phase of the slurry in the vertical scrubbing section 110 and interact with soderjasimi oxidized in the scrubber section 110 and is almost completely oxidized in the reaction tank 130 with the formation of sulfate. The presence of the main component is caused mainly by the dissolution of calcium carbonate with the formation of bicarbonate and hydroxide ions, which occurs in the scrubber section 110, and in the reaction tank 130. In order to ensure the sufficient completeness of the reaction is preferably, as in the prior art, to use oxygen bubbling, although some oxygen can be obtained from the flue gas in the scrubber section 110. To a certain extent, the reaction proceeds in a falling droplets, but the main part of the reaction takes place in the reaction tank 130 into which a slurry. One of the most effective, distinctive features of the invention is that the length of stay in the reaction tank in comparison with the conventional accepted magnitude of approximately 15 hours, reduced to about 6 hours. Reducing length of stay in the reaction tank has the next advantages from the point of view of simplicity of the process, machine size and quality of the gypsum obtained as a by-product.

The preferred pH value of the slurry in the reaction tank 130 is from about 5.0 to note the th content of the main component in a liquid slurry and consequently to an increased ability of a liquid to absorb SO2.

The advantage of the invention lies in the fact that the calcium carbonate comes in the form of fine particles and is directed to the recirculation, as described below, also in the form of fine particles, it is possible to increase the content of the main component. In previously known systems to increase the speed of reaction of calcium carbonate usually use low pH values, but in normal conditions due to the reduction of the number of available main component that slows down the absorption of SO2in the scrubber section. Particles of small size according to the present invention provide a high content of available main component even at pH values that are lower than required, to a considerable extent thereby compensating the influence of low pH on the ability of the sludge to wash the gas.

With the reaction vessel 130 and a group of spray devices, placed in a vertical scrubbing section 110, associated feeder sprayable slurry containing at least the pump 122 and communicated with him nozzle 124 for removal of slurry from the reaction tank 130 and feed it to the group with spray devices located inside the scrubber section.

With the first chamber 174 with bag filters and metered through the airlock 176 in the compressed air stream, coming on line 178, which in turn is injected directly into the scrubber 100 or duct 20 in the place of its direct connection with the scrubber. Alternatively limestone from baghouse 174 with bag filters can be mixed in any tank and injected into the reaction vessel 130. Grinding limestone at the place of entry or near it can be hard to adjust the particle size of the crushed material. The particle sizes are particularly important for carrying out the invention. In a preferred embodiment, srednevekovoi the size of the particles in the flow of fresh calcium carbonate supplied instead of calcium carbonate, lost in the interaction with SO2and with gypsum obtained as a by-product, and soluble chlorides, as described below, is approximately 8 μm or less with a content of 99% or more particles smaller than 44 microns.

The air in line 178 facilitates the supply of oxygen for the oxidation of calcium sulfite to calcium sulfate. The contents of the tank preferably be mixed by conventional means which are not shown.

With the reaction vessel 130 is also connected system maintain the quality of the sludge, signposted the Sano, in the form of fine particles, and for concentration of fine particles of calcium carbonate for their return to the process and removal of plaster applied hydrocyclone 181, which removes the portion of the slurry contained in the reaction vessel 130. Hydrocyclone 181 separates sludge discharged from the reaction tank, the recirculation flow 184, rich in fine particles of calcium carbonate and directionspanel solid material, and another stream containing the bulk of the relatively large particles of calcium sulfate. The preferred particle sizes of calcium carbonate and directionspanel solid material must meet srednevekovogo diameter in the range of from about 1 to about 8 microns, preferably from about 2 to about 6 microns. Srednevekovoi the suitable diameter of the particles of calcium sulfate ranges from about 25 to about 55 microns. Preferably srednevekovoi particle diameter of the calcium sulfate is usually at least 2 times, more preferably 5 to 10 times exceeds, srednevekovoi particle diameter of calcium carbonate. Such a system includes at least one pump 182 and reported to him the pipe 183 to remove cuttings from the reaction vessel and feeding it into hydroc the supply pipe 184 for submission of the hydrocyclone recirculation flow, rich in calcium carbonate. An important feature of the system is in the wash recirculation flow, namely, the recirculation stream 184. With the recirculation pipe 184 reported discharge pipe 185, which serves to remove from this recirculation pipe part is returned to the process stream. On line 183 or elsewhere, it is preferable to provide a device for determining the chloride content in the sludge and for controlling the amount of sludge removed in the washing process line 185, in order to regulate the chloride content in the slurry is within acceptable limits, for example, below approximately 30,000 mg/l, preferably below 20000 mg/l For the higher chloride content inherent tendency to slow the dissolution of calcium carbonate and reducing the concentration of available main component in the slurry for washing gases. Stream 185 is characterized by very high chloride concentration equal to their concentration in the reaction tank, therefore, is the best tool used for leaching of chlorides.

Directionspanel solid materials in the reaction vessel 130, which arrive to the system with calcium carbonate is the weight amount which is from about 4 to about 12 microns, can accumulate mainly in the recirculation stream 184, accompanied by the increase of their concentration in the reaction tank 130. Control over these directionspanel solids in the recirculation flow can be accomplished by chemical means (i.e. by analyzing their characteristic varieties, for example, silicon dioxide, iron or other materials) or physical means (i.e., either through analysis of the distribution of particle size on the total solid content of the materials, or by any other suitable method). A distinctive feature of the invention consists in regulating the flushing flow 185 so as to ensure control over the content of chlorides, as described above, the control over the content directionspublic solid materials in the reaction tank or simultaneously control for both. The preferred means of control is to regulate the flow rate of 185 it increases or decreases depending on what is needed to maintain the concentration of either chloride or directionspublic solid materials in hard limits. Content directionspublic solid materials in the reaction, the total amount of solid materials.

Deleted thus the nozzle 185 from the reaction vessel solid materials can be discharged to the waste liquid for washing, separating from the liquid or processed in some other way and make them suitable for disposal or use for any other purpose. Liquid for washing can also be treated in a certain way to receive the stream suitable for disposal or use for any other purposes. The present invention is provided not to limit in any way the amount of possible options for placement of flow 185 liquid for washing, but rather to provide only the information that there are numerous methods of handling such a thread, its separation into fractions, return to process them all, or parts thereof, etc., Such methods and means of the processing flow 185 are outside of the scope of the present invention.

There is also a pipe 186 selection callywhite sludge passing from the hydrocyclone and is designed to remove the slurry of calcium sulfate from the hydrocyclone in which the calcium sulfate is contained in the form of particles of larger size than the particles of calcium carbonate.

In Fig. 1 site presents the p 130. The advantage of carrying out the process according to the invention allows to significantly increase the content of the main component in liquid droplets, which are in contact with the containing SOxthe exhaust gas flow. The implementation of the recirculation flow exhaust directly from the hydrocyclone to the point where he is highly enriched with very fine particles of calcium carbonate and is characterized by high pH values and high stoichiometric ratio between calcium and sulfur, gives the opportunity to handle flue gases rich in sulfur, within very short periods of contact.

A preferred value of the stoichiometric ratio between calcium and sulfur-containing compounds in the recirculation stream 184 is usually from about 1.2 to about 2.0, the most preferably from about 1.3 to about 1.4. The concentration of suspended solids in the recirculating flow generally is from about 1 to about 10 wt.%, most often from about 2 to about 6 wt.%. The separation of the main mass of calcium sulfate from limestone in the hydrocyclone 182 in addition to the mentioned increase of steelow in the mud.

One of the advantages of the combination of techniques used in the method according to the invention, consists in that the reaction vessel is characterized by a high stoichiometric ratio between calcium and sulfur-containing compounds, for example, in the range of from about 1.1 to about 1.6, preferably from about 1.2 to about 1.3. When this advantage is combined with an additional distinctive feature in the presence of very small particles of calcium carbonate, it becomes possible to achieve the overall improved efficiency of the process with savings in the size of the equipment and utilization of raw materials.

Preferred particulate materials in the stream 183, coming from the reaction vessel 130 is preferably from about 10 to about 20%, more preferably from about 13 to about 17%. Preferred particulate materials in the stream 186 is from about 30 to about 55%. Stream 186 is directed to the filter 188 or other suitable device for dewatering sludge. Solid gypsum is of high quality and can be used in the manufacture of building materials. The filtrate divert on line 189, you can return it in the reactions is gained is what this thread is no need to remove to prevent the accumulation of chlorides in the system.

In the drop entrainment 140 washed the waste stream substantially freed from captured them with liquid droplets, and changes its direction of motion. If no appropriate measures were taken, at high speeds, gas, made possible according to the invention, there would be problems with the formation of deposits on the roof 102 of the tower and tomanually of known construction. The use of more efficient tomboulides instead of drop entrainment 140 is impossible, because there are no practical, highly effective tomanually for operating speeds of 4.5-6 meters per second, and industrial installations, which could be recommended for use in their place, have an inherent tendency to poor drainage and zachlapywaniu, resulting in an increase in the risk of clogging and low reliability. Therefore, for the implementation of this invention requires a drop entrainment 140 designed for such special purposes.

Preferably, the drop entrainment 140 removed a significant amount of that is taken away moisture and changed the direction of flow of the flue is any speed within a vertical tomboulides 150. In its preferred embodiment, a large part (by weight) of droplets, whose diameter is less than approximately 100 μm, is removed either as a result of their loss from the waste stream, either due to their Association with the formation of larger drops, which can be easily removed in placed further in the process tomboulides.

For drop entrainment 140 should preferably essentially vertical humaniatarian indicated on the drawings position 150. The drop entrainment 140 changes the direction of the main part of the flow from vertical to almost horizontal. This has several advantages, including a weak collision of the sludge with a roof 102 scrubbing tower, which prevents the formation of deposits, which gradually increase to such an extent that break off in large pieces, often reaching a diameter of one meter or more, damaging collectors nozzles, or falling into the reaction vessel 130 and ultimately causing clogging of the spray nozzles 112 and 112'. It is also important that it enables highly efficient to remove from almost horizontal stream of small droplets of the mist by means of vertical tomboulides 150. High humaniatarian okimi speeds than tomboulides similar design, but for vertical flow. Its use also provides improved humaniatarian when processing a horizontal flow. High tomanually is an important feature of the invention, although not necessarily unique, since tomanually for horizontal flows typically used in EDC systems and other industries that need high-performance humaniatarian. However, a unique feature is that the combination of drop entrainment 140 with high tomboulides 150 enables improved tomanually by creating a relatively uniform velocity profile in tomboulides and join the main mass of fine droplets into larger drops in the drop entrainment before the final humaniatarian in high performing tomboulides.

In Fig. 5 shows the preferred embodiment of the drop entrainment 140, which can effectively remove or assemble a critical mass of smaller droplets (i.e., with a diameter of less than 100 microns) and reject the vertical flow of flue gases from the surfaces of the upper wall of the tower. Caplio preferred embodiment, this angle is from about 10 to about 45ofor example, approximately 20o.

In the drop entrainment 140 for collecting droplets due to collisions and to rotate the gas flow in the direction most suitable for subsequent tomanually, apply one-way separator vanes 142. Separate the blades 142 are oriented at an angle to the bottom surface of sets 144, 144', 144", etc. blades 142. Typically, the blade of this type is a plate in the shape of a parallelogram with a smaller size from about 0.15 to about 0,23 m and the large size of from about 0.6 to about 1.5 m Gap between the individual blades, typically, ranges from about 40 to about 70% smaller size of the individual blades. Preferably the angle is from about 20 to about 40oand its exact value depends on the angle and the desired angle of the direction of exhaust flow.

Sets 144, etc. are designed and oriented in such a way as to ensure the most effective drainage. Separate kits are mounted to the configuration of the fabric weave "broken twill", as shown in the drawing. Sets 144, etc. are preferably oriented relative to each other at an angle 6, as a rule, the components from the example which draws on elements 146, the length of which corresponds to the length of each of the sets. Alternative designs of the supporting devices.

Design of drop entrainment 140 provides direct contact wash the blades with stationary mounted tubes 147, equipped with spray nozzles 148, capable of spraying wash water directly on the blades as top and bottom. Washing is usually produced by connecting each of the wash reservoir separately and sequentially, one after the other. High quality wash water and the quantity in which it is used, sufficient to reduce the content on the separating surfaces of saturated solutions of dissolved salts. Good drainage is achieved by using sets 144, etc., in the form of a fabric weave "broken twill", in combination with the use of high-quality wash water and with frequent washings provide the device with virtually no sludge formation.

A distinctive feature of the invention is not necessary that the efficiency of separation of the first drop entrainment 140 was as high as that of the multi-pass separators, already known and espola horizontal enables the use of highly efficient vertically oriented humaniatarian 150. Thus, even though the efficiency of removal of material ablation is lower than it would be expedient for the towers of wet gas cleaning, drop entrainment causes a very low pressure drop, for example, less than about 0.15 inches of water column, and has other advantages from the point of view of Ocidente, drainage, high velocity gas flow and deflection of the gas stream from the upper surfaces of the walls of the tower and in the direction of highly efficient vertical tomboulides 150. Preferred humaniatarian 150 deflection type, for example, with zigzag vent.

Then washed and freed from the mist exhaust stream can be discharged into the atmosphere, in particular through the chimney 160. In another embodiment, freed from the mist exhaust stream prior to discharge heated, in particular, in hatazawa heat exchanger vertical configuration, such as described in co-pending application for U.S. patent 08/257158 rights transferred in the usual way (registration number patent attorney R) and which filed June 9, 1994, on behalf of the authors of the present invention.

The result of a combination improved the key gases, weight which is half the weight of a modern open tower with nozzles. This difference in size in combination with an enhanced ability to absorb SOxshown sludge, determine the overall efficiency of the process by about 30% or more in comparison with that achieved in conventional systems. The overall efficiency of the process is determined by the value of all resources spent on removing unit number SOxfrom the raw gas. They include both capital and operating costs.

The above description illustrates how the specialist in the art may implement the invention, therefore, there is no need to dwell on all obvious modifications and variations of its execution, which become obvious to a person skilled in the art from the description of the invention. Note, however, that all such obvious modifications and embodiments of the subject scope of the present invention, which is defined in the attached claims. This means that the formula of the invention includes all of the claimed elements and stages in any lineup or posledovatel is prohibited otherwise.

1. The wet limestone method of cleaning gases in one-way open tower countercurrent scrubber to reduce the content of SOxin the flue gas, including the flow of flue gas containing SOxfrom bottom to top on the vertical scrubbing tower, the flow in the vertical scrubbing section inside the tower aerosol of droplets of an aqueous slurry of finely ground calcium carbonate, calcium sulphate and inert solid materials and enter into contact with flue gas in countercurrent to the flue gas stream, collecting the sludge in the reaction tank after contact with flue gas, removing the slurry from the reaction tank, processing remote from the reaction tank slurry to obtain a recycle stream rich in fine particles of calcium carbonate, and the other stream rich in particles of calcium sulfate, the introduction of fresh calcium carbonate as raw material in the system in amounts sufficient to replace the remote and returned to the process of calcium, and calcium, which have dissolved and reacted with the SOxpreoccupied with the liquid phase in the scrubber section, characterized in that the flue gas containing SOxinjected into a vertical scrubbing bassikounou thread rich finely dispersed calcium carbonate.

2. The method according to p. 1, characterized in that srednevekovoi the particle size of finely ground calcium carbonate entered as raw material, when the feed is less than about 8 microns.

3. The method according to p. 1, characterized in that the pH value of the slurry as it is entered in the scrubber tower support from approximately 5.0 to approximately 6,3.

4. The method according to p. 1, characterized in that the speed of the gas stream in the scrubber tower support up to about 6 m/s

5. The method according to p. 1, characterized in that the tower of the place which the drop entrainment to reduce the number of droplets and the change of direction of the flow of flue gases.

6. The method according to p. 5, characterized in that the tower by means of drop entrainment change the direction of flow of flue gases by at least 30ofrom the vertical axis of the tower and place it in the direction of gas flow after the drop entrainment vertically mounted humaniatarian.

7. The method according to p. 1, characterized in that the sludge is removed from the reaction vessel, sent to the hydrocyclone with the receipt of the recirculation flow, rich in fine particles of the carbonate is Oia between calcium and sulfur-containing compounds is at least 1.3, and removed stream rich in relatively large particles of calcium sulfite, srednevekovoi diameter which is from about 25 to about 55 microns.

8. The method according to p. 1, characterized in that the sludge away from the reaction vessel after the average length of stay of at least about 8 o'clock

9. The method according to p. 1, characterized in that at least part of the sludge in the recirculation flow back into the reaction vessel at a molar ratio between calcium and sulfur-containing compounds comprising at least 1.3 when the particulate material is less than 10%.

10. The method according to p. 9, characterized in that the molar ratio between calcium and sulfur-containing compounds in the recirculation flow exceeds about 1.4.

11. The method according to p. 9, characterized in that the recycle stream contains less than 5% of the suspended solid material.

12. The method according to p. 1, characterized in that the slurry is injected spray nozzles, located on two levels with the distance between the levels is less than about 2 m, and the direction of discharge from adjacent nozzles alternately change from the top n is in the reaction tank support from about 2 to about 6 microns, and srednevekovoi the particle size of finely ground calcium carbonate when its introduction is less than about 8 microns, and the size of 99 wt.% particles less than 44 microns.

14. The method according to p. 1, characterized in that the pH of the slurry in the reaction vessel is from about 5.8 to about 6,3.

15. The wet limestone method of cleaning gases in one-way open tower countercurrent scrubber to reduce the content of SOxin the flue gas, including the flow of flue gas containing SOxfrom bottom to top on the vertical scrubbing tower, the flow in the vertical scrubbing section inside this tower aerosol of droplets of an aqueous slurry of finely ground calcium carbonate, calcium sulphate and inert solid materials and putting it in contact with flue gas in countercurrent to the flue gas stream, collecting the sludge in the reaction tank after contact with flue gas, removing the slurry from the reaction tank, processing remote from the reaction tank slurry to obtain a recycle stream rich in fine particles of calcium carbonate, and the other stream rich in particles of calcium sulfate, the introduction of fresh calcium carbonate in the Oia, as well as calcium, dissolved and reacted with the SOxpreoccupied with the liquid phase in the scrubber section, characterized in that the flue gas stream is served in a vertical scrubbing tower with a speed of from about 4.5 to 6 m/sec, return to the process in the reaction vessel main part of the recirculation flow, rich in finely dispersed calcium carbonate, while srednevekovoi particle size entered as raw material, finely ground calcium carbonate with the introduction of fresh calcium carbonate is less than about 10 microns.

16. The method according to p. 15, characterized in that the pH of the sludge in the reaction tank support from approximately 5.0 to approximately 6,3.

17. The method according to p. 16, characterized in that the pH value of the slurry when it is input in the scrubber tower is from about 5.8 to about 6,3.

18. The method according to p. 15, characterized in that the tower of the place which the drop entrainment to reduce the number of drops of water and the change of direction of the flow of flue gases.

19. The method according to p. 18, characterized in that the tower by means of drop entrainment change the direction of flow of flue gases by at least 30oregarding ver the military humaniatarian.

20. The method according to p. 15, characterized in that the sludge is removed from the reaction vessel, sent to the hydrocyclone with the receipt of the recirculation flow, rich in fine particles of calcium carbonate, srednevekovoi diameter of approximately 8 μm or less, and the molar ratio between calcium and sulfur-containing compounds is at least 1.3 and removed stream rich in relatively large particles of calcium sulfite, srednevekovoi diameter which is from about 25 to about 55 microns.

21. The method according to p. 20, characterized in that at least part of the sludge in the recirculation flow back into the reaction vessel at a molar ratio between calcium and sulfur-containing compounds comprising at least 1.3.

22. The method according to p. 21, characterized in that the molar ratio between calcium and sulfur-containing compounds in the recirculation flow exceeds about 1.4, and the recirculation stream contains less than 5% of the suspended solid material.

23. The method according to p. 15, characterized in that the calcium carbonate is ground directly before entering idrivesafely particle size of the calcium carbonate in the reaction tank support from about 2 to 6 μm, and srednevekovoi the particle size of finely ground calcium carbonate when its input is less than about 8 microns, with a size of 99 wt.% particles less than 44 microns.

24. The wet limestone method of cleaning gases in one-way open tower countercurrent scrubber to reduce the content of SOxin the flue gas, including the flow of flue gas containing SOxfrom bottom to top on the vertical scrubbing tower, the flow in the vertical scrubbing section inside this tower aerosol of droplets of an aqueous slurry of finely ground calcium carbonate, calcium sulphate and inert solid materials and enter into contact with flue gas in countercurrent to the flue gas stream, collecting the sludge in the reaction tank after contact with flue gas, processing remote from the reaction tank slurry in the cyclone with getting the recirculation flow, rich in fine particles of calcium carbonate, and the other stream rich in particles of calcium sulfate, and the input of fresh calcium carbonate as raw material in the system, characterized in that what is the preferred srednevekovoi particle diameter of calcium carbonate fed to the scrubber tower, the support is equal to p the support equal to at least 1,1, when collecting the sludge in the reaction tank pH support from approximately 5.0 to approximately 6,3, sludge is removed from the reaction vessel after the average length of stay of less than about 6 hours, processing remote from the reaction tank slurry is carried out to achieve srednevekovogo size of the fine particles of calcium carbonate less than about 6 microns and srednevekovogo particle diameter of the calcium sulfate from about 25 to about 55 microns, return to the process in the reaction vessel at least part of the recirculation flow, rich in finely dispersed calcium carbonate, the value of the molar ratio between calcium and sulfur-containing compounds in the return process part of a recirculation flow rate of at least 1,4, and fresh calcium carbonate as raw material is introduced into the system in amounts sufficient to replace the remote and returned to the process of calcium, and calcium, which have dissolved and reacted with the SOxpreoccupied with the liquid phase in the scrubber section, and srednevekovoi particle size of input finely ground calcium carbonate support less than about 8 microns.

25. The method according to p. 24, otlichayetsa flue gases.

26. The method according to p. 24, characterized in that the slurry is introduced into a vertical scrubbing section of the tower spray nozzles, located on two levels with distance between them of less than about 2 m, and the direction of discharge from adjacent nozzles alternately change from upper to lower and Vice versa.

27. The method according to p. 24, characterized in that the calcium carbonate is ground directly before entering as raw material in the slurry to maintain 99% of the content of the carbonate particles with a size less than 44 microns, and srednevekovoi particle size of the calcium carbonate in the reaction tank support from about 2 to 6 μm, and srednevekovoi the particle size of finely ground calcium carbonate when its input is less than about 8 microns, with a size of 99 wt.% particles is less than 44 microns.

28. The wet limestone method of cleaning gases in one-way open tower countercurrent scrubber to reduce the content of SOxin the flue gas, including the flow of flue gas containing SOxfrom bottom to top on the vertical scrubbing tower, the flow in the vertical scrubbing section inside this tower aerosol of droplets of an aqueous slurry of finely ground calcium carbonate, sulfate is gas, collection of sludge in the reaction tank after contact with flue gas, removing the slurry from the reaction tank, the treatment of sludge removed from the reaction vessel, providing a recirculation stream, rich in fine particles of calcium carbonate, and the other stream rich in particles of calcium sulfate, the input of fresh calcium carbonate as raw material in the system in quantities sufficient to replace the remote and returned to the process of calcium, and calcium, which opened and interacted with SOxpreoccupied with the liquid phase in the scrubber section, characterized in that the flue gas stream is served with a speed of more than about 4.5 m/s, the slurry is introduced into shrubbery tower through spray nozzles located on two levels with distance between them of less than about 2 m, and the direction of discharge from adjacent nozzles alternately change from top to bottom and Vice versa, and return to the process in the reaction vessel at least part of the recirculation flow, rich in finely dispersed calcium carbonate.

29. The method of reducing the content of SOxin the flue gas wet scrubbing, including the flow of flue gas, which contains Alicia, of calcium sulfate, calcium sulfite and directionspublic solid materials in countercurrent to the flue gas stream, collecting the sludge in the reaction tank after contact with flue gas, maintaining the high reactivity of the slurry through the slurry from the reaction tank and remote processing of sludge in the hydrocyclone with the receipt of the recirculation flow, rich in fine particles of calcium carbonate, and the other stream rich in calcium sulfate, both of these stream containing dissolved chloride, and removing the calcium sulfate in the form of a solid material and a portion of the recirculation flow to remove any soluble chlorides or directionspanel solid material, or both, and the input of fresh calcium carbonate as raw material in the system in quantities sufficient to replace the calcium removed by separating the calcium sulphate and the distal part of the recirculation flow, characterized in that srednevekovoi the particle size of finely ground calcium carbonate, input in the form of slurry in the scrubber tower is from about 1 to about 8 microns, and when the input of fresh calcium carbonate as raw material in the system srednevekovoi Raposo reducing the amount of SOxin flue gases, including the use of the scrubber tower having a box to enter a gas duct for gas outlet and a vertical scrubbing section, the configuration of which provides a flow of flue gas in this section from the bottom up, placing a group of spraying devices within the specified scrubbing section, the configuration of this group provides input aerosol of an aqueous slurry of finely ground calcium carbonate, calcium sulfate, calcium sulfite and directionspublic solid materials in countercurrent to the stream of flue gas, the supply of the raw material of calcium carbonate, performing the reaction tank, below the group of the spray device and used to collect sludge after a period of contact with flue gas in a vertical scrubbing section, the removal of slurry from the reaction tank and the feed sludge to the group of spraying devices in the scrubbing section, and maintaining a low chloride content in the sludge in the reaction tank by removing cuttings from it and feed the remote slurry in the cyclone with getting the recirculation flow, rich in fine particles of calcium carbonate, and the other stream, which is rich relatively more cu is usually used to provide interaction of SOxwith calcium carbonate with the formation of crystals of calcium sulfate, srednevekovoi the diameter of the particles of which at least 2 times the size of the particles of calcium entered as raw materials, and to maintain a low concentration of chlorides in the sludge define their content in the recirculating stream and remove a portion of the recirculation flow in accordance with the results of determination of the chloride content.

31. The method of reducing the content of SOxin the flue gas wet scrubbing, including the flow of flue gas containing SOxfrom the bottom up by scrubbing tower, the input aerosol of an aqueous slurry of finely ground calcium carbonate, calcium sulfate, calcium sulfite and directionspublic solid materials in countercurrent to the flue gas stream, collecting the sludge in the reaction tank, maintaining a low concentration of chlorides in the sludge in the reaction tank by removing cuttings from it and feed the remote slurry in the cyclone with getting the recirculation flow, rich in fine particles of calcium carbonate, and the other stream rich in relatively large particles of calcium sulfate, return to the process part of the recirculation flow directed in the reaction is d fresh calcium carbonate in the system in amounts sufficient to replace the remote calcium, characterized in that the pH of the sludge in the reaction tank support from approximately 5.0 to approximately 6,3, and that to maintain a low concentration of chlorides in the sludge in the reaction tank determine the chloride content in the recirculating stream and remove a portion of the recirculation flow in accordance with the results of determination of the chloride content, the molar ratio between calcium and sulfur-containing compounds in the return process part of the recirculation stream is greater than about 1.3, and srednevekovoi the particle size of finely ground calcium carbonate is less than about 10 microns.

32. Device for wet gas cleaning to reduce the content of SOxin flue gases containing scrubbing tower, equipped with a box for entering gases, a conduit for exhaust gases and a vertical scrubbing section, providing a flow direction of flue gas from the bottom up through it, the group placed inside the scrubber section of the spray device that provides input to the stream of flue gas aerosol of an aqueous slurry of finely ground calcium carbonate in a countercurrent to this stream, the reaction of reserved contact with the flue gas within a vertical scrubbing section, device for feeding into the reaction vessel in the form of raw materials of calcium carbonate, feeder slurry spray, containing at least one pump connected therewith a pipe for draining slurry from the reaction tank and the feed slurry to the group of spray devices, the system maintain the quality of the sludge containing the hydrocyclone can share coming from the reaction tank slurry flow, rich in fine particles of calcium carbonate, and the flow of relatively larger particles of calcium sulfate, at least one pump and associated pipe for draining slurry from the reaction tank and the feed slurry in the cyclone, the recirculation pipe that goes from the hydrocyclone to the reaction tank and serves for the supply of the hydrocyclone recirculation flow, rich in calcium carbonate, the discharge pipe which is connected with this recirculation pipe and serves to remove the portion of the recirculation flow, and the exhaust from the cyclone outlet to remove the slurry of calcium sulfate, characterized in that the reaction vessel is made with dimensions that allow interaction of SOxwith calcium carbonate with the formation to the Nata calcium, entered as raw material, and the feeder of calcium carbonate in the reaction tank adapted to feed particles with srednevekovym size of less than about 10 microns.

 

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The invention relates to improvements associated with the separation of liquid droplets from gas streams, with a high degree of efficiency and reliability, and in the preferred embodiment, with the removal of sulfur oxides (SOxfrom flue gases

The invention relates to energy, in particular to flues industrial energy technology installations and structures, and can be used in all sectors of the economy to remove different amounts of air, General ventilation, contain harmful impurities

The invention relates to heat engineering, can be used in thermal power stations and other industrial sites associated with the combustion of fuel, and can improve the efficiency of flue gas cleaning nitrous oxide

The invention relates to the field of sanitary cleaning of industrial gas emissions from dust and impurities with recovery of the absorbent with a view to its reuse and recycling of absorbed substances

The invention relates to devices for blast furnaces for industrial purposes, such as steel, steklovarennyh, furnaces of thermal power plants, etc

The invention relates to a wet cleaning gas emissions from dust and harmful impurities by selective absorbents with subsequent recovery of absorbents and disposal of absorbed substances
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