KR101644899B1 - Method and device for treating gas by injecting a powdered compound and an aqueous phase - Google Patents

Abstract

The invention relates to a method of treating a gas comprising the steps of: injecting a powder compound into a gas line, injecting the aqueous phase into the tube in a droplet form, capturing contaminants from the gas, Respectively. The step of injecting the aqueous phase into the droplet form is carried out to humidify the particles of the powder compound of the gas line when they are injected.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method and apparatus for treating a gas by injecting a powdered compound and an aqueous phase,

The present invention relates to a method for treating a gas having a set flow direction in a gas conduit and an apparatus for injecting the powdered compound.

The invention includes the following steps:

a) injecting the powdered compound through a powdered compound injection tube at the injection point of the powdered compound in the flue gas conduit such that a cloud of particles or stream of particles of the powdery compound is allowed to form in the gasted conduit Wherein the injection tube has an outer surface and an inner surface arranged to contact the powdered compound,

b) injecting a monophasic liquid aqueous phase into the gas conduit as a non-word,

c) capturing contaminants of the gas using the powdered compound, and

and d) separately recovering the pollutant-enriched powdered compound and the pollutant-depleted gas, in a gas conduit having a set flow direction.

Typically the treatment of gases, especially flue gases, requires the reduction of acid gases, in particular HCl, SO ₂ and / or HF, which under dry conditions, dry the powdered substance, usually minerals, Or by injecting through a filter-bed containing solid particles that are fixed or in motion. In this case, the powdered compound generally comprises a calcium-magnesium compound, in particular a lime, preferably a sodium compound such as slaked lime or hydrated lime or sodium carbonate or sodium bicarbonate. Other mineral compounds may also be used, especially those used to reduce heavy metals, including dioxins, furans and / or mercury, such as those based on phyllosilicates such as sepiolite or haloisite.

The present invention more particularly relates to a process for reducing acid gases in a flue gas, in particular a flue gas, by introducing a powdery product having the ability to trap acid contaminants in a gas stream, in order to improve the reduction yield of the acid gas components of the treated gas It is on the way to let.

More specifically, it has been known that treating these flue gases with powdered hydrated lime is improved by the use of humidified hydrated lime instead of dry powdered hydrated lime. In fact, the absorption of contaminants in the gas phase by solid phase particles is improved by the presence of water. Sometimes such flue gas treatment is described as a semi-drying method. The method of using hydrated lime and water is also known as a method in which milk of lime is injected into the flue gas stream. Unfortunately, the injection of lime oil is energy-consuming, prone to wear and corrosion, and takes the practice of special means (dispersing turbines, circulation pumps) that can cause clogging problems. Literature CN 2011 68568 and JP 10-216 572 each propose an intended solution to solve clogging problems by preparing a lime oil suspension in situ during injection to solve clogging problems. For this purpose, a lance consisting of two concentric tubes, an inner tube and an outer tube, is used. Water is injected through the inner tube while hydrated lime is injected through the outer tube. According to CN 2011 68568, the position of the inner tube can be adjusted in relation to the outer tube, and thus the output hole at the same height for the output hole of the protruding or folding or further outer tube hydrated lime for water It is possible to have an inner tube.

According to these documents, the design of the spray lance ensures that the water injection tube is internal to the injection tube of powdered hydrated lime. The result is therefore that the sprayed lime encounters an obstacle in the outer spray tube placed in the inner tube for the injection of water. In this way, the hydrated lime comes into contact with the generally metallic and cold surfaces of the inner tube, and the lime then tends to become clogged.

Further, according to these references, the humidity level of hydrated lime results in a water / lime mass ratio of 5 to 6 to form a ground suspension. This suspension actually causes a side effect of the harmful effect in that the gas is further cooled significantly during the injection of the hydrated lime against the treatment of the flue gas. This makes it possible to use flue gases that are hot enough for decontamination to be effective; However, this is not currently in demand, and business owners are increasingly becoming more and more likely to reclaim the heat of flue gases for economic and environmental reasons.

Moreover, when hydrated lime comes into contact with the cold surface, this is the surface of the inner tube for injecting the water of these documents, so condensation takes place in the hydrated lime injection tube, which also promotes clogging of the injection tube Thereby interfering with the injection of lime into the flue gas stream.

Finally, as mentioned above, high water / lime mass ratios result in water usage and mass consumption.
A device for injecting lime into flue gas is also known in which an external concentric tube surrounds a powdered or hydrated lime feed tube and through which gas is injected (see US 2012/0251423).

It is an object of the present invention to allow the treatment of gases, in particular flue gases, with powdered compounds, preferably mineral compounds, especially hydrated lime, which significantly reduces the risk of clogging, minimizes water consumption, To overcome the disadvantages of the state of the art by providing a method that allows for the absence of cooling and thereby the recovery of the calories from these gases to be treated being unimpeded.

In order to solve this problem, according to the present invention, as indicated at the outset, the step of injecting the single-phase liquid aqueous phase as a non-versatile liquid may be carried out in a non-malleable manner to humidify the powdery compound particles, Characterized in that the process is carried out in the rolling or flow of the powdery compound particles inside the gas conduit according to a weight ratio between the applied single-phase liquid phase and the injected powdery compound of not less than 0.05 and not more than 1.2, Phase injection is performed through at least one single-phase liquid aqueous phase injection tube disposed in a peripheral space located around the outer surface and having an outer cover, the method further comprising: providing at least one insulating layer And the outer surface is separated by the outer surface.

According to the present invention, the humidification of the powdered compound is carried out at the injection point of the powdered compound in the gas conduit / stream to be treated. In this way, the particles of the mineral compound and the aqueous phase droplets coexist very locally, and the powdery compound is humidified in situ and in a controlled manner.

In the cloud of the aqueous phase droplets and particles of the injected powdery compound as a weight ratio of the aqueous phase to the powdery compound as a droplet, the aqueous phase droplet layer is thus formed on the surface of the particles of the powdery compound, Thereby facilitating transfer of the substance to the solid phase of the powdered compound. The aqueous phase droplet layer is obtained through controlled co-injection of the powdery compound particles and the aqueous phase according to the above weight ratio and the in situ humidification of the powdery compound avoids the problem of clogging of the injection lance against powdery compounds, particularly humidified hydrated lime. It is.

More specifically, the aqueous phase is injected into a position very close to the injection point of the powdery compound.

By "very close" is meant in the context of the present invention that the distance between the aqueous phase injection point and the injection point of the powdered compound is less than or equal to the injection point of the powdered compound or the diameter of the injection pipe, .

Advantageously, the powdered compound is a mineral compound. It may contain a calcium-magnesium compound, in particular lime, preferably hydrated lime or hydrated lime. In certain embodiments, the mineral compound is selected from those based on those used to reduce heavy metals, including dioxins, furans, and / or mercury, such as sepiolite or halosite. The powdery compound used may also be of organic, in particular carbonaceous, in particular activated carbon or anthanocoke type. The powdered compound may also be a mixture of these compounds.

Preferably, the aqueous phase is water which is liquid or selected from the group consisting of alkali metal, especially hydroxides, carbonates, bicarbonates, nitrates, phosphates, persulfates and monocarboxylates of sodium, potassium and / or lithium and mixtures thereof An aqueous solution of an alkali compound or an aqueous solution of a compound based on ammonia or a urea such as an ammonium salt or an aqueous solution of a compound based on an alkali or alkaline or ammonium halide, especially chlorides and / or bromides of sodium, potassium, calcium or magnesium Aqueous solution. Moreover, the aqueous phase may also or may not contain acids, especially organic acids, bifunctional acids (dibasic acids).

In any case, the aqueous phase is essentially monophasic. In other words, the aqueous phase consists essentially of liquid, especially liquid water.

Advantageously, the temperature of the aqueous phase prior to injection into the flue gas conduit is less than 100 占 폚, preferably less than 40 占 폚, particularly less than 30 占 폚, more particularly less than 20 占 폚.

According to a particular embodiment, the step of injecting an aqueous phase is carried out in close proximity downstream of the injection point of the powdered compound relative to the set flow direction of the gas in the gas conduit.

The term "very close downstream" of the injection point of the powdered compound means from the point of view of the present invention that the aqueous phase droplet is sprayed directly behind the powdered compound with respect to the flow direction of the gas. Thus, the injected powder compound first encounters the gas and immediately afterwards encounters a droplet formed in the aqueous phase, thus allowing for the humidification of the powdery compound rather than the gas to be treated.

In another specific embodiment, the step of injecting an aqueous phase is carried out in close proximity to the injection point of the mineral compound with respect to the set flow direction of the flue gas of the flue gas conduit.

Advantageously, the step of injecting the powdery compound is carried out in a gas conduit according to an injection direction which forms an angle of 90 to 150 degrees, preferably 145 degrees, preferably less than 140 degrees, in particular 135 degrees, .

In certain embodiments, the aqueous phase droplets have an average droplet size of 500 to 5,000 [mu] m, preferably 500 to 5,000 [mu] m, depending on the injection conditions.

Preferably, the powdery compound, especially the powdered hydrated lime, has an average particle size d ₅₀ of less than 80 μm, advantageously less than 50 μm, preferably less than 35 μm, preferably less than 25 μm, and in particular less than 10 μm, .

It is recognized that the powdered compound may be another powdered compound, particularly a carbonaceous compound, especially an activated carbon or a powdered mineral compound co-injected with an Atan Coke type.

More specifically, according to the method of the present invention, the powdery compound, especially hydrated lime, is added to the gas conduit at a humidity of 0.2 to 10%, especially 0.5 to 4%, preferably less than 2%, in particular less than 1.5% Water content content).

Practically, running problems occur when the free water content of the powdered compound is greater than 10%. In particular, when the powdery compound is calcium hydroxide (hydrated lime), if the free water content is greater than 2% or 4%, it becomes difficult or very difficult to handle (problems with flow, water, etc.).

In certain embodiments according to the present invention, the weight ratio between said aqueous phase injected non-literally and said injected powdered compound is greater than or equal to 0.1, preferably greater than 0.2 and less than 1, more particularly less than 0.8. This weight ratio is relatively small compared to that indicated in the prior art CN 2011 68568 and JP 10-216 572 and does not cause the cooling of the gas to be substantially treated since the reduced portion of the water added according to the invention is not powdered Because it allows humidification of the compounds, especially hydrated lime, and thus a considerable cooling of the gas.

Indeed, in the prior art CN 2011 68568 and JP 10-216 572, a high weight ratio of between 5 and 6 between water and hydrated lime is affected by the fact that the suspension of hydrated lime (lime oil) is sprayed into the gas to be treated. In this case, the temperature of the gas is greatly reduced by the injection of a large amount of water, which consumes heat during evaporation.

In a particularly advantageous manner, in the process according to the invention, said gas is heated to a temperature of from 10 to 1,100 ° C, in particular from 10 to 100 ° C, in particular from 15 to 80 ° C, in particular from 20 to 70 ° C, Preferably 130 占 폚 to 250 占 폚, preferentially 150 占 폚 to 230 占 폚, especially 160 占 폚 to 220 占 폚. In another alternative method of the method according to the invention, the gas is heated to a temperature of 300 ° C to 500 ° C, preferably 320 ° C to 450 ° C, preferentially 330 ° C to 400 ° C, or 850-1100 ° C, preferably 900 ° C To 1,100 占 폚, preferentially from 950 占 폚 to 1,050 占 폚.

As can be seen, the temperature of the gas is substantially unaffected by the size of the small amounts of water and droplets according to the invention, which essentially contribute to the humidification of the powdered compound. Furthermore, since the injection of the aqueous phase takes place in the cloud of the injected powdered compound, in particular very close to the injection point of the powdered compound, the contact between the particles of the aqueous phase droplets and the particles of the powdered compound is promoted and very fast, An optimal reduction of the acid pollutant, facilitated by the water layer formed around the particles of the < RTI ID = 0.0 >

In an alternative method of the process according to the invention, the gas is heated to a temperature of from n to n-10 占 폚, preferably from n to n-8 占 폚, preferably from n to n-5 占 폚, after the injection of the aqueous phase as the powder compound and droplet, Especially from n to n-3 [deg.] C, where n is the temperature of the gas prior to injection of the powdered compound and the aqueous phase.

In particular, in an advantageous embodiment, the injection of the aqueous phase is preferably carried out at a pressure of from 2 to 150 bar through a spray tube, such as a flat jet fan. In an alternative method, this pressure would instead be a pressure of 2 to 20 bar, preferably 3 to 15 bar, preferentially about 8 bar. In another alternative method, the pressure will be between 20 and 150 bar, especially between 30 and 100 bar. These high pressures avoid contamination of the tube.

In this way, in this particular embodiment of the invention, very fine droplets are obtained and at that moment it is not required to produce a vapor cloud according to the invention, allowing it to be well dispersed as very fine droplets, The high pressure can be used because it contributes to the contact efficiency between powder particles and the powdered compound particles by improving their humidification without cooling the hot gases.

Other embodiments of the method according to the invention are indicated in the appended claims.

The object of the invention is also an apparatus for injecting a powdered compound, preferably a mineral compound, especially powdered hydrated lime, to be introduced into a flue gas conduit, the apparatus being fed by a source of the powdered compound, a source of the powdered compound, Wherein the powder compound injection tube has an outer surface and an inner surface arranged to be in contact with the powdery compound and the device for injecting the powdery compound further comprises a single phase liquid aqueous Phase liquid aqueous phase supplied by the source of the single phase liquid aqueous phase and the source of the single phase liquid aqueous phase.

Such devices are known from the state of the art, for example, from literature CN 2011 68568 and JP 10-216 572. In these documents, which are intended to provide an apparatus suitable for treating flue gas with lime oil (suspension), the water inlet tube is designed for a larger diameter tube for injecting hydrated lime to produce a suspension of hydrated lime in situ It is arranged concentrically.

As mentioned in document CN 2011 68568, in a specific apparatus for treating flue gas with lime oil, provisions are made such that the position of the inner tube can be adjusted in relation to the location of the upper tube. In such a case, the inner tube to the water has a protruding or folding output opening or is at the same height as the hydration lime output opening of the outer tube.

Regrettably, regardless of the selected form, the presence of a concentric inner tube with respect to the hydrated lime spray tube utilizes the abutment of hydrated lime particles with respect to the water injection inner tube. Therefore, the hydrated lime comes into contact with the metallic cold surface of the inner tube, and the lime then tends to clog. Therefore, the solution provided for the preceding clogging problem is quite relative.

Further, according to these references, the intent to form a suspension of hydrated lime in concentric form and in situ results in the need for a water / lime ratio of 5 to 6. Unfortunately, in such cases, devices according to CN 2011 68568 and JP 10-216 572 result in cooling the flue gas, thereby increasing the tendency to recover heat from the flue gas to suggest more economic and environmentally-friendly methods It raises a new problem for the industrial workers who are doing it.

Finally, when hydrated lime comes into contact with the cold surface, this is the case of the surface of the water injection inner tube of these documents, condensation occurs in the tube for injecting hydrated lime, which also results in clogging of the injection tube Thereby disturbing the injection into the flue gas stream of lime.

It is an object of the present invention to provide a device which permits the injection of a powdery compound, preferably a mineral compound, in particular hydrated lime, and the humidification of its particles upon treatment of the gas, Which provides the possibility of not requiring cooling of the gas and thus not interfering with the recovery of the heat from these gases being treated.

In order to solve this problem, according to the invention, as indicated above, at least one tube for injecting the single-phase liquid aqueous phase is disposed in a peripheral space disposed around the outer surface of the powdered compound injection tube, Wherein one insulating layer is disposed in the peripheral space between the outer surface of the powder injection tube and the outer cover.

In this manner, the powdered compound injected into the tube for injecting the powdered compound does not encounter any obstacles and much less cold or metallic surfaces that tend to deposit and clog when encountered. Furthermore, the at least one tube with respect to the aqueous phase disposed in the peripheral space disposed around the outer surface of the tube for injecting the powdered compound is thereby capable of injecting the aqueous phase droplet, especially the liquid water, . Proximity means in the context of the present invention that the distance separating the outer diameters of each tube for injecting the aqueous phase and the powdered compound is less than or equal to the diameter of the tube for injecting the powdered compound and preferably less than the radius do.

Moreover, the particular form of the tube for injecting the at least one tube and powdered compound for injecting the aqueous phase can be achieved by just humidifying the powdered compound, in particular lime, and in the latter case without forming any lime oil suspension Providing the possibility of treating the gas through a pseudo-dry process. This operation is carried out without a significant amount of humidification of the gas, and therefore the heat recovery for it is increasingly required to cool the desired gas. This particular form does not require a high water / lime weight ratio, unlike the state of the art as disclosed in the documents CN 2011 68568 and JP 10-216 572, and has a value of 5 to 6 to 1.2 or less, preferably 1 or less, more specific To a value less than or equal to 0.8. Thus, the cloud of particles of the powdered compound in a particular hydrated lime is produced in the flow of the flue gas, and the aqueous phase droplets, especially water, are injected into the gas stream in a relatively small amount. These aqueous phase droplets meet dense clouds of powdered compound particles and improve the reduction of pollutants, especially of the acid compounds of the gas, without cooling the gas.

In a preferred embodiment, the apparatus comprises a plurality of tubes for non-malleable implantation of an aqueous phase, each tube being connected to a dispenser connected to a source of the aqueous phase, And each tube is further provided with a valve.

Advantageously, in the apparatus according to the invention, each tube for injecting the aqueous phase is arranged in a concentric tube, and the tube for injecting the aqueous phase outwardly is retractable.

More specifically, in accordance with the present invention, each tube for injecting the aqueous phase comprises an output orifice as a slot or flat sprayer.

In an alternative of the present invention, the dispenser has an aqueous phase of 2 to 150 bar, in particular 2 to 20 bar, preferably 3 to 15 bar, more preferentially about 8 bar, alternatively 20 to 150 bar, especially 30 to 100 bar Lt; RTI ID = 0.0 > pressurized < / RTI > Of course, this can be liquid water, which can be utilized directly in aqueous phase feeds, in particular at the pressures mentioned above.

As indicated above, according to the invention, there is provided an apparatus comprising an outer cover around said peripheral space.

The apparatus according to the present invention includes at least one insulating layer in the peripheral space between the outer surface of the tube for injecting the powdery compound and the outer cover.

In yet another embodiment of the present invention, the apparatus further comprises a device for closing the peripheral space, wherein the peripheral space is provided with a hole for the powdered compound and a series of holes with at least one hole for the aqueous phase, The holes for the compound are arranged to receive the outlet of the tube for injecting the powdered compound and each hole for the aqueous phase is arranged to receive the outlet of each tube for injecting the aqueous phase.

Preferably, in the device according to the invention, the outer cover has a diameter of 100 to 250 mm, preferably less than 200 mm, and more preferentially 110 to 170 mm, in particular 125 to 150 mm.

Advantageously, said tube for injecting the powdered compound has a diameter of 75 to 150 mm, preferably 80 to 125 mm, in particular about 100 mm.

More specifically, according to the present invention, each tube for injecting an aqueous phase has a diameter of 5 to 30 mm, preferably 6 to 20 mm, more preferably 8 to 16 mm.

Other embodiments of the device according to the invention are indicated in the appended claims.

Other aspects, details and advantages of the invention will be apparent from the following description, and without any limitations with regard to the accompanying drawings.

1A is a schematic side view of a first embodiment of a gas treatment apparatus according to the present invention.
1B is a cross-sectional view along line II of FIG. 1A.
2A is a schematic side view of a second embodiment of a gas treatment apparatus according to the present invention.
Figure 2b is a cross-sectional view along line II-II in Figure 2a.
Fig. 3 is a schematic side view of an embodiment according to Fig. 1 of a gas treatment apparatus according to the invention, used for example in a flue gas conduit, in which the direction of injection of the powdery compound is perpendicular to the direction of flue gas flow.
Figure 4 is a schematic side view of a second embodiment according to Figure 2 of the gas treatment apparatus according to the invention used in a flue gas conduit wherein the direction of injection of the powdered compound is also perpendicular to the flow direction of the flue gas.
5 is a schematic side view of an embodiment according to FIG. 2 of a gas treatment apparatus according to the present invention used in a flue gas duct. In the drawing, the direction of injection of the powdery compound is arranged obliquely with respect to the flow direction of the flue gas.
Figures 3-5 illustrate, among others, a method for coupling an apparatus according to the invention to a flue gas conduit.
In the drawings, the same or similar elements include the same reference numerals. The injected powdered compound is an example of having mineral essence and the treated gas is flue gases.

1A and 1B, an apparatus according to the present invention is an apparatus 1 for injecting a powdered mineral compound to be introduced into a flue gas conduit, which comprises a powder phase (not shown) connected to a source of powdered mineral compound And a tube 2 for injecting a mineral compound. The tube for injecting the mineral compound is arranged to pass through the flue gas conduit 3 (see FIG. 3) and to allow the discharge of the mineral compound through the discharge hole 14 for the mineral compound. The tube (2) for injecting the mineral compound has an outer surface (4) and an inner surface (5). During operation, the inner surface (5) is in contact with the powdered mineral compound during use in the injection tube (2).

In this illustrated embodiment, the apparatus for injecting a powdered mineral compound 1 comprises a tube 6 for injecting a plurality of aqueous phases, each connected to a distributor 7 connected to an aqueous phase feed 8. As can be seen in Figures 1a or 1b, each tube 6 of a plurality of injection tubes is disposed around the mineral compound injection tube in a space outside the mineral compound injection tube, referred to herein as the peripheral space 9. Each aqueous phase injection tube 6 further comprises a valve 10 disposed between the distributor 7 and the aqueous phase outlet 11 of each aqueous phase injection tube 6. The aqueous phase discharge 11 as a droplet from each aqueous phase injection tube is made practically and advantageously by means of an aqueous phase discharge orifice by a nozzle (not shown), in the form of a slot of a flat spray.

By means of the valves 10 it is possible not only to supply a part of the pipe 6 but also to supply only those located downstream from the injection point of the mineral compound with respect to the flow direction G of the flue gas in the flue gas conduit 3, It is possible to supply.

The distributor (7) is connected to the pressurized aqueous phase supply (8). In other arrangements, the pressure means 12 provide the possibility of imparting the intended pressure to the water entering through the water supply 8. The pressure of the aqueous phase feed (8) is typically 2 to 150 bar. Alternatively, the pressure will be between 2 and 20 bar, preferably between 3 and 15 bar, and more preferentially about 8 bar. Alternatively, the pressure may be between 20 and 150 bar, especially between 30 and 100 bar. This high pressure provides the possibility to avoid contamination of the tube.

The mineral compound injector further includes a flange 13 provided with a through-hole 18 to allow it to be attached or attached to an apparatus for treating the flue gas through a flue gas conduit by any other means do.

In fact, as can be seen in figure 3, the flue gas conduit 3 to be treated comprises a hole for introducing the device 1. [ The device is introduced into this hole and is attached to the conduit by the flange 13 and attachment means 15 in the usual manner. By tightly locking the flange 13, the possibility of maintaining the pressure on the outer surface 16 of the flue gas conduit 3 is provided, but also the sealing of the connection of the device according to the invention is ensured.

In the embodiment shown in Figs. 1A and 1B, a second flange 17 is present on the flue gas treating apparatus. The flange (17) is provided with a series of through-holes (19) arranged to receive the attachment means. The flange 17 is arranged to be connected to a current mineral compound source (not shown).

Advantageously, an outer cover 20 is present around said peripheral space 9. The outer cover 20 preferably has a diameter of 100 to 250 mm, preferably less than 200 mm, more preferentially 110 to 170 mm, in particular 125 to 150 mm.

In the peripheral space 9, an insulating layer may be provided between the outer surface 4 of the mineral compound injection tube and the outer cover 20. The insulation may simply be air or any other insulating material known to those skilled in the art. The insulating layer provides the possibility of avoiding cooling of the outer surface (4) separated from the tube (6) which reduces the risk of flocculation on the inner surface (5) of the mineral compound circulating in the mineral compound inlet tube.

The device according to the invention further preferably further comprises a cap or device (21) for closing said peripheral space. The cap is provided with a series of holes, of which there are discharge holes for mineral compounds and discharge holes 11 for many aqueous phases, such as the existing aqueous phase tube 6.

To inject the mineral compound, a cylindrical tube 2 of stainless steel having a diameter of about 125 mm is typically used, which is mounted on the flange 13. Stainless steel is the source of condensation and clogging of mineral compounds, and therefore the tube 2 (mineral compound injection tube 2) of the stainless steel should be as short and possible as possible (no obstruction) to reduce the square area. As a result, substantially cylindrical tube 2 (in particular, warpage can be used as illustrated in Figure 2a), should take these considerations into account. Briefly, the apparatus according to the invention is characterized in that at least one aqueous phase injection tube (6) is substantially cylindrical in shape without producing any obstruction to the flow of particles of the mineral compound in the substantially cylindrical tube / tube (2) And a columnar mineral compound injection tube 2 which is deformed so as to be inserted along the mineral compound injection pipe 2. In the embodiment illustrated in Figures 1a, 1b and 3, eight tubes 6 for injecting a non-aqueous aqueous phase are arranged around the mineral compound injection tube 2, (6) can be integrated into the flange (13).

Typically, the powdered mineral compound injection tube 2 has a diameter of 75 to 150 mm, preferably 80 to 125 mm, especially about 100 mm. In general, each water injection tube 6 has a diameter of 5 to 30 mm, preferably 6 to 20 mm, more preferably 8 to 16 mm.

Above all, when it is desired to treat the flue gas of the duct with hydrated lime to lower the acid pollutants, the apparatus according to the invention is arranged, for example, as shown in FIG. The hydrated lime is then injected into the hydration lime injection tube (2) and leaves the tube through the exit hole (14). Wherein the particles of hydrated lime clay have a mean particle size d ₅₀ of typically less than 80 占 퐉, advantageously less than 50 占 퐉, preferably less than 35 占 퐉, preferably less than 25 占 퐉, more in particular less than 10 占 퐉, And is formed in the conduit 3 of the flue gas to be treated. Advantageously, before being injected into the flue gas, the hydrated lime has a humidity of from 0.2 to 10% by weight, in particular from 0.5 to 4% by weight, preferably less than 2% by weight, in particular 1.5% by weight.

The pressurized aqueous phase enters the dispenser 7 through the supply 8 and into the water injection tube 6 where the valves 10 or some valves are in the open position.

According to an improved embodiment of the method according to the invention, the step of injecting the aqueous phase as a droplet is carried out in the flue gas conduit (3), in the flow direction of the flue gas (indicated by double arrow G in figure 3) Is carried out in said cloud or flow of the mineral compound of said flue gas conduit (3), in the proximity downstream from said injection point. In this way, the injected powdered mineral compound is humidified and the flue gases are either untreated or only very small amounts are treated. With respect to the flow direction of the flue gas to be treated, the injection of the aqueous solution droplets in the vicinity of the injected particles of the mineral compound is carried out by closing the valves 10 present on the aqueous phase injection tube 6 located upstream, This is accomplished by removing the valves of the deployed pipe.

In the apparatus shown in Fig. 3, only the aqueous phase droplet injection tube (downstream with respect to the gas flow) under pressure disposed in the portion S of the flue gas according to the invention has valves in the open position, while the other pressurized droplet The injection tube may have valves in the closed position. In this way, the injected pressurized aqueous phase droplets are introduced downstream from the inlet of the mineral compound particles, and the mineral compound particles are advantageously humidified.

The pollutants of the flue gas are then trapped by the mineral compounds, which is an improved mode by the presence of aqueous phase particles surrounding the mineral compound particles. Next, flue gases depleted of mineral compounds and contaminants enriched with pollutant compounds are recovered separately in a conventional manner, in particular by filtration.

Therefore, the mixing device for the injection of the mineral compound / aqueous phase according to the invention is a simple, easy and inexpensive concept which offers the possibility of improving the capture of the acid gas from the flue gas.

The temperature of the flue gas is typically between 100 and 1,100 ° C. In some plants, this temperature varies from 110 캜 to 350 캜, preferably from 130 캜 to 250 캜, more preferentially from 150 캜 to 230 캜, particularly from 180 캜 to 220 캜. In other cases, especially in the operation of producing SO ₂ as the main pollutant, the temperature of the flue gas is typically 250 ° C to 500 ° C or 850 ° C to 1100 ° C at a more upstream position (closer to the combustion zone) Preferably 300 占 폚 to 450 占 폚 or 900 占 폚 to 1,100 占 폚 at a more upstream position, and preferably 330 占 폚 to 400 占 폚 or 950 占 폚 to 1,050 占 폚 at a more upstream position. The humidifying effect of mineral compounds is for a relatively short period of time because aqueous phase droplets evaporate very quickly in hot gases. Therefore, contact between the mineral compound particles injected into the flue gas and the droplets should be done as quickly as possible.

The size of the aqueous phase droplets varies from 500 to 5,000 microns, preferably from 500 to 1,000 microns or from 1,000 to 5,000 microns, on average, depending on the conditions of the injection, and in particular to a tube having a flat exit hole (as a slot) through which aqueous phase droplets are formed . The size of the resulting droplets also facilitates contact between the aqueous phase droplets injected into the cloud of particles of the mineral compound and the mineral compound particles as soon as they are injected into the flue gas conduit.

As mentioned earlier, the injection or pre-humidification of mineral compositions, especially wet hydrated lime (containing 2% or more, even 4% water) into the flue gas causes aggregation of the particles, Which is generally difficult. Furthermore, wet hydrated lime or pre-humidified lime is easier to carbonate (rather fast), which leads to a reduction in trapping performance. Finally, the agglomerated particles of mineral compounds, especially wet hydrated lime, have a reduced trapping ability due to their reduced accessibility to pores. Typically, fine particles are required to improve capture performance. The use of the apparatus according to the invention allows in situ humidification of the fine mineral compound particles themselves injected into the treated flue gas conduit and the particles react particularly with the acid gas in the cloud of directly generated aqueous droplets and also in the hot flue gas It evaporates very quickly and dries in place. Therefore, water evaporation occurs before the particles have time to agglomerate.

This is also due to the fact that according to the invention the amount of water injected is just the amount of water needed to humidify the mineral compound particles and to form clouds formed using mineral compound particles and aqueous phase droplets. The weight ratio between the non-aqueous injected aqueous phase and the injected powdery mineral compound is 1.2 or less, preferably 1 or less, especially 0.8 or less. The weight ratio is also 0.1 or more, particularly 0.2 or more. Thus, the fine unmelted injected aqueous phase exhibits only very little effect on the temperature of the flue gas being treated and does not disturb the subsequent potential steps for heat recovery. According to the present invention, the flue gas is heated to a temperature of from n to n-10 占 폚, preferably from n to n-8 占 폚, preferably from n to n-5 占 폚, especially from n to n-3 占 폚 , Where n is the temperature of the flue gas after the mineral compound and the aqueous phase is injected.

In accordance with the present invention, it is evident that typically both aqueous phase and mineral compound injection systems are attached to the same apparatus for treating flue gas, they operate independently of each other. Therefore, in actual cases, if necessary, it is possible to operate by injecting only an aqueous phase droplet or only a mineral compound.

Figure 2 shows another device for treating flue gas in accordance with the present invention.

As can be seen, the device 1 according to the invention comprises a tube 2 for injecting powdered mineral compounds connected to a powdered mineral compound source (not shown) in the figure. The tube for injecting the mineral compound is arranged to pass to the flue gas conduit 3 (see FIGS. 4 and 5) and to allow the mineral compound to flow out through the vent hole 14 for the mineral compound. The tube (2) for injecting the mineral compound has an outer surface (4) and an inner surface (5). In operation, the inner surface (5) is contacted with the powdered mineral compound injected into the injection tube (2).

The apparatus 1 for injecting a powdered mineral compound also comprises a tube 6 for injecting the aqueous phase in a non-malleable state, which is connected to the aqueous phase supply 8 and which is connected to a concentric tube . The tube for injecting the aqueous phase, although not shown in the drawing, may further include a shutoff valve 10. The discharge orifice 11 for the aqueous phase which is discharged from the aqueous phase of the injection tube as a molar is actually made as a slot or a flat sprayer.

The pressure of the aqueous phase feed (8) is typically 2 to 150 bar. Alternatively, the pressure will be between 2 and 20 bar, preferably between 3 and 15 bar, and more preferentially about 8 bar. Alternatively, the pressure may be between 20 and 150 bar, especially between 20 and 100 bar. This high pressure provides the possibility to avoid contamination of the tube.

The mineral compound injector is further provided with through-holes 18 to allow the device for treating the flue gas to be connected to or attached to the flue gas conduit via the flange 23 by any other means (13).

In fact, as can be seen in Fig. 5, the flue gas conduit 3 to be treated may comprise an introduction conduit 22 for the device 1 according to the invention. The introduction conduit 22 is provided with a flange 23 at its end. The device (1) according to the invention is introduced into this conduit and is attached thereon by flanges (13 and 23).

4 and 5, the step of injecting the powdered mineral compound is carried out at a temperature of 90 to 150 DEG C, preferably 145 DEG C or less, preferably 140 DEG C or less, particularly 135 DEG C or less Is carried out in the flue gas conduit (3) according to the angle.

This orientation of the tube relative to the mineral compound with respect to the flow direction of the flue gas is never relevant to the embodiment of the device according to the invention. This means that embodiments including the plurality of aqueous phase injection tubes shown in Figures 1 and 3 can also be oriented in a tilted manner relative to the walls of the conduit of the flue gas.

Furthermore, the device according to the invention can be inserted into the flue gas duct, if necessary, with the versions shown in Figs. 1A, 1B, 2A and 2B, and penetrates into the gas duct, typically by a length of 0 to 40 cm .

In this embodiment, the technical considerations such as the length of the tube according to the invention and the operating parameters of the device differ to the extent as described for Figs. 1A, 1B and 3.

In the embodiment shown in Figures 2a and 2b, a second flange 17 is present on the apparatus for treating the flue gas. In this flange 17, a series of through-holes 19 are arranged to receive the attachment means. The flange 17 is arranged to be connected to a source of mineral compounds (not shown).

Advantageously, an outer cover 20 is present around said peripheral space 9. The outer cover 20 preferably has a diameter of 100 to 250 mm, preferably less than 200 mm, more preferentially 110 to 170 mm, in particular 125 to 150 mm.

In the peripheral space 9, a clue may be formed between the outer surface 4 of the powdered mineral compound injection tube and the outer cover 20. [ The insulation can be simply air or any insulating material known to those skilled in the art and provides the possibility of avoiding the cooling of the outer surface 4, whereby the mineral compounds circulating in the injection tube 2, in particular of hydrated lime (6) which reduces the risk of aggregation of the particles.

The apparatus according to the invention is further characterized in that it is provided with a series of holes, preferably with discharge holes 14 for mineral compounds and discharge holes of tubes concentric with the aqueous phase injection tube 11, Further comprising a cap or device (21).

Also, as can be seen in the embodiment shown in Figures 2a, 2b, 4 and 5, the aqueous phase injection tube 6 is arranged in a concentric tube from which an aqueous phase injection tube 25 can enter, The possibility of cleaning or replacing the aqueous phase injection tube is provided without interrupting the injection of the aqueous phase injection tube. In order to facilitate extraction from the aqueous phase injection tube, the present invention provides a slight curvature of the mineral compound injection tube, which is kept as small as possible to avoid the obstruction inside the tube where the mineral compound is essentially circumferential, It reduces the aggregation of mineral compounds on the walls.

In connection with the embodiment shown in Figures 2a, 2b, 4 and 5, the main piping for injecting the mineral compound typically has a diameter of 100 mm, and the tubes concentric with the aqueous phase injection tube have a diameter of 25 mm Diameter. Both tubes are limited to a cover 20 having a diameter of about 125 mm.

Example

Example  One.

The SO ₂ reduction test was performed using the pilot facility described in WO 2007/000433 (Fig. 2, p. 10, l. 20 to p. 12, l. In the tubular reactor, calcium hydroxide (hydrated lime) particles were mixed with 1,500 mg / Nm ³ of SO ₂ , 9% by volume of CO ₂ and 10% by volume of H ₂ O and having a total flow rate of 1.132 Nm ³ / As a co-current with a gas having a temperature of < RTI ID = 0.0 >

Two types of hydrated lime were used. The first sample (Sample 1) was hydrated lime obtained according to the teachings of the patent application WO 97/14650. The second sample (Sample 2) was hydrated lime obtained according to the teachings of the patent application WO 2007/000433.

The table below shows the SO ₂ reduction level obtained by varying the humidity of the reagents tested for a stoichiometric factor of 2.5 and an absorbent flow rate of Q from 0.7 wt% to 4.1 wt% based on the weight of hydrated lime.

Q sorbent flow rate corresponds to the hydrated lime flow rate needed to neutralize the SO ₂ flow rate and if the yield of the reaction was 100% (stoichiometric equilibrium), multiply by the "stoichiometric" factor, And does not participate in the reaction. In this case, Q has a value of 5.05 g / h.

Sample Humidity at 150 ° C, mass% SO2 versus the stoichiometric factor of 2.5
decrease (%) Sample 1 0.7% 18 2.0% 27 2.6% 28 3.0% 29 3.7% 29 4.0% 29 Sample 2 0.9% 27 1.9% 36 2.6% 38 2.7% 39 3.8% 36 4.1% 35

Example  2. - Industrial Testing

The parameters of the flue gas are:

Total flow rate: 20,000 Nm ³ / h

Temperature: 180 ° C

Water content: 4 to 5 vol%

O ₂ content: 15 to 18 vol%

The hydrated lime prepared according to the teachings of the patent application WO 2007/000433 was injected upstream from the sleeve filter to reduce SO ₂ . 1,800 mg / Nm ³ upstream from the sleeve filter And lime consumption when the lime was humidified compared to the situation where the lime was not humidified (17 dm ³ / h water or 0.25 water / lime mass ratio) for an SO ₂ content of 700 mg / Nm ³ at the outlet Lt; RTI ID = 0.0 > 20% < / RTI > In practice, 35% conversion rate of lime is observed when lime is not humidified and 40% conversion is humidified. The apparatus of FIG. 1 in accordance with the present invention was used; The device had a slope of about 120 ° with respect to the flow direction of the gas.

Example  3. - Industrial test

The parameters of the flue gas are:

Total flow rate: 250,000 Nm ³ / h

Temperature: 150 ° C

Water content: 10 vol%

O ₂ content: 16 vol%

The hydrated lime produced according to the teachings of the patent application WO 2007/000433 was injected upstream from the sleeve filter to study the effect of its humidification level on the SO ₂ reduction level.

Thereby, for an SO ₂ content of 224 mg / Nm ³ upstream from the sleeve filter and for the same lime consumption (flow rate of 50 kg / h), the SO ₂ content at the outlet of the filter was 134 mg / Nm (equivalent to the lime conversion rate of 53%) ^3, and when the lime is to be humidified with water in an amount of 30 dm ³ / h (water / lime weight ratio of 0.6 Im) (conversion rate of 67% lime) 112 mg / Nm ³ Respectively. Therefore, humidified lime allows to obtain an SO ₂ reduction of 25% compared to the same non-humidified lime.

Example  4. Industrial Testing

Standard hydrated lime was injected into the same facility and using variables of flue gas as in Example 3 to study the effect of humidification level on SO2 reduction levels.

Thereby, for SO ₂ levels of 420 mg / Nm ³ upstream from the sleeve filter and for the same lime consumption (120 kg / h flow rate), the SO ₂ content obtained at the outlet of the filter was 336 mg / Nm ³ (equivalent to a conversion of 20% of lime), 266 mg / Nm ³ (conversion of lime of 37%) when lime is humidified with water of 30 dm ³ / h (water / lime mass ratio is 0.25) And a lime of 241 mg / Nm ³ (conversion of lime of 43%) when humidified with an amount of 120 dm ³ / h (water / lime mass ratio is 1). Therefore, the lime humidified with water in the amounts of 30 and 120 dm ³ / h allows to obtain SO ₂ reductions of 85% and 110%, respectively, compared to the same non-humidified lime.

It is to be understood that the invention is in no way limited to the embodiments described above and that many modifications may be made thereto without departing from the scope of the appended claims. For example, it is possible to combine the presence of the distributor 7 with a single water injection tube 6 or any other desired number of tubes in an apparatus for treating flue gas in accordance with the present invention. It is also possible for the assemblies of Figures 3 and 4, as in Figure 5, to include an introduction conduit 22 with a flange 23 at its end.

Claims (25)

CLAIMS What is claimed is: 1. A method of treating a gas having a flow direction set in a gas conduit, comprising the steps of:
a) allowing a powdered compound to be introduced into the gas conduit through the powdered compound injection tube at the injection point of the powdered compound to form a cloud or a stream of particles of the powdered compound in the gas conduit, Having an outer surface and an inner surface arranged to be in contact with the inner surface,
b) injecting the single phase liquid aqueous phase into the gas conduit as a non-verbal,
c) capturing contaminants of the gas using the powdered compound, and
d) separately recovering the pollutant-enriched powdery compound and contaminant-depleted gas,
Wherein the step of injecting the single phase liquid aqueous phase in a non-marginal state comprises injecting a single phase liquid into the gas conduit, in order to humidify these powdery compound particles in the gas conduit during injection from among the injected cloud or flow of the powdery compound particles inside the gas conduit. Wherein the step of injecting the single phase liquid aqueous phase is carried out according to a weight ratio of between 0.05 and 1.2 between the aqueous phase and the injected powder phase and wherein the step of injecting the single phase liquid aqueous phase comprises providing at least one single phase liquid aqueous Wherein the method of treating a gas having a set flow direction in the gas conduit is further separated from the outer surface by at least one insulating layer disposed in the peripheral space, A method for treating a gas having a set flow direction. The method of claim 1, wherein the step of injecting the powdery compound is performed in a gas conduit along an injection direction forming an angle of 90 to 150 degrees with respect to a direction of gas flow. The method of claim 1, wherein the powdered compound has an average particle size d ₅₀ of less than 80 μm. The method of claim 1, wherein the powdered compound has a moisture (water content content) of 0.2 to 10% before being injected into the gas conduit. The method of claim 1, wherein the weight ratio between the aqueous phase injected non-literally and the injected powdered compound is 0.1 to 1. The method according to claim 1, wherein the gas has a temperature of from 10 캜 to 100 캜 before injection of the powdery compound. The method of claim 1, wherein the gas has a temperature of between about 100 DEG C and about 300 DEG C before injection of the powdered compound. The method of claim 1, wherein the gas has a temperature of between about 300 ° C and about 500 ° C prior to the injection of the powdered compound. The method of claim 1, wherein the gas has a temperature between 850 ° C and 1,100 ° C prior to the injection of the powdered compound. The method of claim 1, wherein the gas has a temperature of n to n-10 占 폚, after injection of the powdered compound and a non-aqueous aqueous phase, wherein n is from 10 占 폚 to 1,100 占 폚. 11. A process according to any of the claims 1 to 10, characterized in that the injection of the aqueous phase is carried out at a pressure of from 2 to 150 bar. 11. The process according to any one of claims 1 to 10, wherein the powdery compound is a carbonaceous organic compound selected from mineral compounds selected from hydrated lime, sodium carbonate or sodium bicarbonate, halite and sepiolite, activated carbon and atan coke, ≪ / RTI > 11. A process according to any one of claims 1 to 10, characterized in that the aqueous phase consists of water or an aqueous solution of an alkali or ammonia-based compound or an aqueous solution based on a halide or acid. An apparatus for injecting a powdered compound into a flue gas conduit (3)
The apparatus comprises a powdered compound injection tube (2) which is supplied by a source of the powdered compound, a source of the powdered compound and is arranged to pass toward the gas conduit, the powdered compound injection tube being arranged to be in contact with the powdered compound (4) and an inner surface (5), said powder compound injector further comprising at least one tube for injecting the aqueous phase supplied by said single-phase liquid aqueous phase source and said single- 6)
The at least one single phase liquid aqueous phase injection tube 6 is arranged in a peripheral space 9 located around the external surface 4 of the powdered compound injection tube 2 and has at least one insulation Layer is disposed in the peripheral space between the outer surface (4) of the powdered compound injection tube and the outer cover (20). 15. The apparatus according to claim 14, comprising a plurality of tubes (6) for non-literally injecting an aqueous phase, each connected to a distributor (7) connected to said aqueous phase source, said plurality of single phase liquid aqueous phase injection tubes (6) Characterized in that each of the tubes of the device is arranged in the peripheral space and has a stop valve (10). 15. Apparatus according to claim 14, characterized in that each aqueous phase injection tube (6) is arranged in a concentric tube and the aqueous phase injection tube is retractable outwardly of the concentric tube. 15. An apparatus according to claim 14, wherein each aqueous phase injection tube (6) comprises a discharge orifice (11) as a slot. 16. Apparatus according to claim 15, characterized in that the distributor (7) is connected to a pressurizing means for applying a pressure of 2 to 150 bar to the aqueous phase. 15. The device of claim 14, further comprising a device for closing the peripheral space, the device comprising a series of holes including a powder compound hole and at least one aqueous phase hole, Wherein each of the aqueous phase holes is arranged to house an outlet of each aqueous phase injection tube. 15. The apparatus of claim 14, wherein the outer cover (20) has a diameter of 100 to 250 mm. 15. The apparatus according to claim 14, wherein the powder compound injection tube (2) has a diameter of 75 to 150 mm. 22. Apparatus according to any one of claims 14 to 21, characterized in that each aqueous phase injection tube (6) has a diameter of 5 to 30 mm. delete delete delete

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