TW202045239A - Device and method to disperse sorbent particles in a flue gas duct - Google Patents

Abstract

A sorbent dispersion method and device for reducing the amount of noxious compounds in effluent gas streams from industrial processes. Exhaust gases pass through an exhaust duct (107) where they are contacted with a sorbent composition which injected into the exhaust gas stream through an injector device. The injector device has a central passageway (101) through which the sorbent composition is conveyed by positive air pressure. At least one nozzle (108) is mounted about the exterior of the injector device and is arranged at an impingement angle with respect to a centerline (106) of the injector device to more fully effect dispersion of the sorbent particles within the exhaust gas stream.

Description

Device and method for dispersing and absorbing particles in flue gas duct

The present invention generally relates to absorbent injection assemblies and methods for injecting absorbent into exhaust gas ducts for reducing the amount of harmful compounds in exhaust gas streams from industrial processes, energy production, and the like.

As we all know, fuel combustion in industrial processes and energy production produces many potential pollutants, including fly ash and acid gases. The release of these pollutants into the atmosphere needs to be minimized. Reducing the acid gas content in the exhaust gas before it is discharged into the surrounding air is a way to reduce air pollution. Specifically, reducing the contents of SO ₂ , SO ₃ , H ₂ SO ₄ , HCl, HF, etc. and heavy metals (such as Sb, As, Be, Cr, Mn, Hg, Se, etc.) of the exhaust gases provides many advantages. Such as reducing unsightly gas plumes, reducing corrosive by-products and reducing the risk of harmful human exposure. One area where these problems are common is the area of coal-fired power plants, which generates a large amount of SO ₂ and/or SO ₃ . There are also other industrial processes involving the formation of gaseous emissions containing acid gases, including, for example, sulfuric acid plants and other industrial chemical plants, waste incinerators, non-coal-fired power plants (such as oil-fired power plants), large diesel generators, boilers, and bricks. And ceramic furnace and lime and cement kiln operation.

The common elements of various combustion systems of this general type include a combustion chamber and a burner located in the combustion chamber for igniting fuel. Fuel (such as coal or biomass) is fed to the combustion chamber, where the fuel is quickly ignited and stabilized on the burner. Any of many of the aforementioned undesirable components included in the fuel (for example, acidic components or metal components) can enter the environment through the flue gas exiting the exhaust stack, and can cause undesirable results.

The prior art is full of various flue gas desulfurization ("FGD") methods that have been developed to reduce the amount of acid gas in the exhaust gas, particularly with regard to the aforementioned SO ₂ , SO ₃ and/or H ₂ SO ₄ . A common method is to use a dry alkaline absorbent, such as slaked lime, namely Ca(OH) ₂ , where the absorbent is introduced into the exhaust gas duct of the particular industrial process of interest. The flue gas from this industrial process passes through the exhaust gas duct and reacts with the absorbent in the exhaust gas duct. The resulting reaction of the absorbent with the acidic compound forms a particulate solid, for example, CaSO ₃ or CaSO ₄ . These solid reaction products can then be removed in a downstream baghouse or other collection system.

The prior art has taught that it can be achieved by combining the absorbent with a large amount of supplemental air (for example, about 2000 scfm) in the device before spraying into the catheter from the respective outlets to achieve the dry powder injected into the absorbent injection system. Improve dispersion and uniformity. However, there are disadvantages associated with the use of extremely high ambient air velocities and, in some cases, even interfere with the overall operation of the facility for processing flue gas.

The method of the present invention provides a solution to these and other long-term needs in the industry in a way that is easy to implement and cost effective, but does not require the use of large amounts of makeup air as sometimes used in the past.

The present invention relates to an improved equipment and method for reducing the acid gas content of exhaust gas (e.g., flue gas) produced by coal-fired power plants. It uses an absorbent composition (e.g. slaked lime), which achieves the effect of absorbing particles Increase dispersion. This increased dispersion of particles reduces the mean free path of the exhaust gas molecules diffusing to the surface of the absorbent, thereby increasing the overall efficiency of the process.

Therefore, the main purpose of the device of the present invention and the method of using the device is to fully disperse dry powder (such as slaked lime, powdered activated carbon, various clays and other modified or unmodified minerals, trona, sodium bicarbonate, etc.) Introduced into exhaust gas ducts of industrial processes to treat one or more pollutants from combustion smoke, including acid gases (such as SO ₂ , SO ₃ , HCl, HF, etc.) and heavy metals (such as Sb, As, Be, Cr, Mn) , Hg, Se, etc.). As will be explained more fully in the written description below, the device and method of the present invention can be designed to provide both tangential (edge-to-edge) dispersion and lateral (depth) penetration into the catheter to provide a pollution-reducing absorbent to provide absorption Enhance the uniformity of reagents and process gases and target pollutants.

According to the principles of the present invention, a method for reducing harmful compounds (such as but not limited to acid gases) in the exhaust mixture passing through a conduit having an inner wall defining a flow path through which the exhaust gas passes is shown. According to this method, an absorbent composition (such as but not limited to slaked lime) is introduced into a specially designed absorbent dispersion device, which is also referred to herein as an absorbent injection assembly.

The present disclosure describes an absorbent injection assembly for injecting absorbent into an exhaust gas duct. The absorbent injection assembly includes: an absorbent injection pipe having an inner hole with a longitudinal axis, an inlet and an outlet, the outlet Particularly configured and positioned in the exhaust gas duct, the absorbent injection tube is configured to transport the absorbent through it by a carrier gas so as to inject the absorbent into the exhaust gas duct so that the absorbent flow is parallel to the absorption The axial component of the longitudinal axis of the agent injection pipe leaves the outlet; and at least one nozzle, which is coupled to the supply line of the dispersed gas (such as air) by the following: specifically configured to be coupled to the inlet of the dispersed gas supply line and The outlet is arranged near the outlet of the absorbent injection pipe, and the nozzle is oriented toward the longitudinal axis of the absorbent injection pipe to project the dispersed gas flow onto the absorbent flow leaving the outlet of the absorbent injection pipe, wherein the absorbent The result is an increased dispersion of the absorbent provided in the exhaust gas duct.

As explained in more detail below, this absorbent injection assembly allows for increased dispersion of the absorbent in the exhaust duct. Specifically, by injecting the absorbent stream from the absorbent injection pipe, the absorbent stream collides with the dispersed gas (for example, air), and the particles of the absorbent stream are further dispersed, thereby achieving greater dispersion and reducing discharge The mean free path for gas molecules to diffuse to the surface of the absorbent.

In the embodiment of the absorbent injection assembly, the nozzle is fixed to the absorbent injection tube.

In another embodiment of the absorbent injection assembly, the nozzle is spaced apart from the absorbent injection tube.

In another embodiment of the absorbent injection assembly, the nozzle is fixed on the sleeve surrounding the absorbent injection tube and includes a hole extending from the first end connected to the air supply line to at least the second end forming the outlet.

In another embodiment of the absorbent injection assembly, the absorbent injection tube is surrounded by a sleeve, and the sleeve and the outer wall of the absorbent injection tube form an annular chamber, wherein the sleeve carries at least one connected to the annular chamber The nozzle, and the annular chamber is connected to the air supply line.

In a preferred embodiment of the absorbent injection device, at least two nozzles are provided around the outlet of the absorbent injection pipe.

In another embodiment of the absorbent injection tube, a circular tube carrying a plurality of nozzles surrounds the absorbent injection tube, and the tube is connected to the air supply line.

A preferred absorbent injection device includes a plurality of specially configured and oriented air nozzles or injectors, which are installed around and extend from a conventional dry absorbent spray gun. As previously explained above, the spray gun has a central channel for delivery of absorbent. The absorbent (such as but not limited to slaked lime) is introduced into the central channel of the spray gun by means of a carrier gas stream. The injector or nozzle is a curved pipe that has an outer surface and an inner channel or hole. Each of the injectors also has an inlet end and an outlet end used as an air nozzle. Those skilled in the art will understand that various other nozzle configurations can be used. The nozzle or injector has any other shape, provided that the outlet of the air nozzle faces the axial centerline of the spray gun and is specifically contained between 0 and 120 degrees. The angle. The nozzles can communicate with each other via a central air line running adjacent to the spray gun, which is connected to a compressed air source. Depending on the angular orientation, the specific configuration of the injector relative to the spray gun located in the center can provide tangential (side-to-side) dispersion as well as lateral (in depth) dispersion. The absorbent is discharged from the central channel of the spray gun to the duct to react with the pollutants of the exhaust gas conveyed in the exhaust duct, thereby reducing the concentration of harmful components in the exhaust gas.

It is desirable to maintain the carrier gas velocity of the absorbent into the catheter at a reasonable velocity. High velocities can cause wall buildup due to colliding particles. For this reason, increasing the flow rate of the carrier gas to improve the dispersion of the absorbent in the exhaust gas duct is not a desired option. According to the present invention, the absorbent is dispersed in the exhaust gas conduit by the dispersion gas flowing through at least one nozzle arranged near the outlet of the absorbent injection pipe, without the need for excessively fast carrier gas velocity.

For further explanation, the prior art has taught that the absorbent can be combined with a large amount of make-up air (~2000 scfm) in the absorbent injection spray gun to achieve the dry powder injection before spraying into the exhaust gas duct from separate outlets. Improve dispersion and uniformity. However, the method of the present invention achieves improved absorbent dispersion by using a relatively low volume (ie, <400 scfm) compressed air collision after the absorbent stream is sprayed from the spray gun. Under normal FGT operating conditions, the absorbent powder is supplied to the spray gun assembly of the device at a mass flow rate of 1 to 20,000 lb/h. At the same time, compressed air supplied at 1 to 400 scfm and pressurized to 0.5 to 200 psig is delivered to the central air line of the absorbent injection pipe. The resulting collision air (also referred to as dispersion gas in this disclosure) from the air nozzle and directed toward the discharge absorbent stream increases the dispersion of the absorbing particles, thereby increasing the total volume in the duct occupied by the injected dry powder. Therefore, the exposure of the exhaust gas to the particulate absorbent is increased, thereby improving the overall performance of the process of using the particulate absorbent to remove pollutants from the exhaust gas. Increased absorbent dispersion allows further penetration into the catheter and improves contaminant mitigation and/or neutralization.

In one configuration, the device for practicing the method of the present invention includes (1) a cylindrical dry absorbent spray gun with a length of 6 to 240 inches and an inner diameter of 1 to 10 inches, and (2) a length of 0.25 to 6 inches And as many as 20 replaceable cylindrical air nozzles (injectors) with an inner diameter of 0.1 to 2 inches. The outlets of the air nozzles form an angle of 0 to 120 degrees toward the axial center of the spray gun. The nozzles communicate with each other via a central air line running adjacent to the spray gun, which is connected to a compressed air source.

There are various improvements with respect to the features indicated in the above-mentioned aspects of the invention. Other features can also be incorporated into the aspects mentioned above. These improved forms and additional features can exist individually or in any combination. For example, the various features discussed below in relation to any of the illustrated embodiments of the invention may be incorporated into any of the aspects of the invention set forth above, individually or in any combination.

The present invention provides an improved absorbent injector system (also referred to as an absorbent injection assembly) that meets the above objectives. With reference to the non-limiting examples illustrated in the accompanying drawings and detailed in the following description, the invention described herein and its various features and advantageous details are explained more fully. The descriptions of well-known components and manufacturing processes and manufacturing techniques are omitted so as not to unnecessarily obscure the working principle of the present invention. The examples used herein are only intended to promote the understanding of the ways in which the invention of this text can be practiced, and to further enable those skilled in the art to practice the invention. Therefore, the examples should not be construed as limiting the scope of the claimed invention.

Turning first to Figure 4, which shows a simplified schematic diagram of the absorbent injection system that is the target of the method of the present invention. The injection system includes a spray gun 11 (also called an absorbent injection pipe), which is installed in the side wall 13 of an exhaust gas duct 15 of the type used for conveying exhaust gas from an industrial or energy process. The process can be, for example, coal-fired power plants, which generally produce large amounts of SO ₂ and/or SO ₃ . However, many other types of industrial processes also involve the formation of gaseous emissions containing acid gases, including, for example, the previously mentioned sulfuric acid plants and other industrial chemical plants, waste incinerators, non-coal-fired power plants (such as oil-fired power plants), Operation of large diesel generators, boilers, brick and ceramic furnaces, and lime and cement kilns.

The exhaust gas stream processed in accordance with the method of the present invention may include any number of acidic compounds, such as SO ₂ , SO ₃ , H ₂ SO ₄ , HCl and/or HF. Moreover, the concentration of these gases before treatment may be on the order of about 50 ppm to about 3000 ppm, but these concentrations are not limited to the present invention. The temperature of the exhaust gas in the duct will generally be in the range of about 250°F to about 800°F (about 121°C to about 427°C), this is just an example. In other applications, such as in the case of furnace absorbent injection (FSI), temperatures up to about 2200°F can be envisaged.

Any number of absorbent compositions (including combinations thereof) can be used in the absorbent injection system of the present invention. Such materials include, for example, slaked lime, quicklime powder, powdered activated carbon, clay and other modified or unmodified minerals, trona and sodium bicarbonate. In this general case, calcium oxide CaO is usually called "quicklime", and calcium hydroxide Ca(OH) _{2 is} called "slaked lime", and both are sometimes informally called "lime". Quicklime is usually in the form of lumps or pebble, but it can also be powder. Dry hydrated lime is usually powder. In the meaning of the present invention, "powder" means substantially composed of particles below about 2 mm, specifically below 1 mm or even below 500 µm and especially above 0.1 µm, specifically 0.5 µm之Solid.

A particularly preferred absorbent composition is powdered slaked lime. However, as mentioned, other compounds can also be used, such as sodium carbonate or bicarbonate or compounds used to eliminate dioxene, furan and/or heavy metals (including mercury), such as layered silicon Salts of them, such as sepiolite or aloroxite or equivalent. Powdered slaked lime (also called slaked lime as used herein) will be understood to mean a group of solid particles consisting mainly of Ca(OH) ₂ (ie calcium hydroxide).

Many suitable absorbent compositions are commercially available. For example, the above types of products are purchased from Lhoist North America (5600 Clearfork Main Street, Fort Worth, Tex. 76109) or from Lhoist Operations around the world. One such product is purchased as "SORBACAL ® SP". This absorbent composition has the following product characteristics: purity higher than 90% (content of Ca(OH) ₂ ); BET specific surface area higher than 18 m ² /g; total pore volume higher than 0.10 cm ³ /g ( 90-1000 Angstroms); and d ₅₀ included in the range between 5 μm and 15 μm.

Hydrated lime or other absorbents can be stored in bulk lime storage bins, and can be transferred to a pneumatic conveying line, for example, by a variable rotating air lock. In the case of using multiple injection units (that is, multiple absorbent injection assemblies are arranged at different positions of the exhaust gas duct), the pneumatic transport absorbent pipeline can be divided into multiple absorption pipelines by using one or more pipeline splitters. Agent feeder pipeline. Each absorbent feeder line is in fluid communication with a respective absorbent injection pipe or spray gun. The air supply line for the nozzle used in the method of the present invention may also include a main conveying line divided into a plurality of air feeder lines. Each air feeder line is in fluid communication with one or more nozzles of a respective absorbent injection assembly.

As briefly discussed in the previous technical section of this article, the above-mentioned general type of absorbent injection process poses many challenges in actual operation in terms of transportation flow rate, injection flow rate, and radial dispersion of powdered compounds in exhaust gas ducts. For example, the injection of powder (absorbent composition) into the exhaust gas duct should be carried out at a pressure greater than the pressure of the flue gas existing in the exhaust duct to prevent the powder from being poorly dispersed therein, and in some cases gathering in the duct On the wall. However, too much pressure can cause problems such as friction/wear and/or blockage of the powder in the transportation pipeline, and when the powder contains slaked lime, the latter phenomenon can also cause the carbonation of the lime powder.

In addition, for the most effective treatment, the powdered absorbent should be evenly dispersed over the entire cross section of the exhaust gas duct (relative to the flue gas flow in the exhaust duct) to allow uniform and effective elimination of gaseous pollutants. This dispersion depends on many factors, such as the size of the conduit and the gas flow rate through the conduit. In order to overcome the problems related to the effective dispersion of absorbents, many prior art systems have utilized "osmotic nozzles" or "spray guns", as they are often mentioned in the industry. These "spray guns" penetrate the side wall of the exhaust gas duct and are therefore completely affected by the flue gas flow. Specifically, the prior art uses "forming spray guns" to transport large amounts of air.

However, even if these "permeable nozzles" or "spray guns" are used, there are still some problems in practice. For example, it is desirable that the spray gun design must be relatively simple in construction and still strong enough to withstand the temperature and acidity conditions it is exposed to in the exhaust duct. In situations where the spray gun needs to be replaced frequently, the operating costs increase because the related furnace may need to be stopped, sometimes for several days. When these furnaces cannot reach their equilibrium quickly and easily during combustion, it is problematic to restart combustion to replace the permeation nozzle every time the furnace is stopped.

For the purpose of the present invention, the most important thing is that although the "permeable nozzle" previously used in the industry allows the powder to be dispersed in the exhaust duct to a certain extent, the "permeable nozzle" fails to achieve the particle absorbent in the exhaust duct. Its excellent dispersion and therefore lack of maximum efficiency.

Due to the problems of the spray gun type injection system, some "no spray gun" systems have also been developed. However, these "no spray gun" injection systems require the extremely high ambient air velocity discussed earlier. As already mentioned, these flow rates are often undesirable and can even interfere with the overall operation of the facility for flue gas treatment. For example, compared with the flue gas flow rate, at such a high ambient air flow rate, the amount of air added to the flue gas is not negligible, and in particular leads to undesired cooling of the flue gas, thereby Reduce the overall energy performance of the furnace. This device also has the effect of increasing the total flow rate and oxygen concentration of the flue gas downstream of the device, thereby forcing the operator to modify the pipeline for flue gas treatment accordingly.

The purpose of the method of the present invention is to overcome the above-mentioned types of problems associated with prior art absorbent injection systems by using an improved "spray gun" injector type device, which allows the absorbent stream to be sprayed from the spray gun by making the absorbent stream Collisions with relatively low volume (˂ 400 scfm) and relatively high pressure air (for example, 0.5 to 200 psig, 75 psig compressed air in one case to be further elaborated) to achieve improved absorbent dispersion. The nozzle configuration used in the improved spray gun design of the present invention collides with the absorbent stream to further disperse the particles of the absorbent, thereby achieving greater dispersion and thereby obtaining a greater surface area in contact with the exhaust gas.

Figure 4 is a simplified schematic diagram of an absorbent injector system featuring the improved absorbent injector device or absorbent injection of the present invention. As shown in FIG. 4, a part of the injector (in this case the spray gun 11) extends through the exhaust gas duct wall 13. The distance the injector extends into the duct should be selected so that the absorbent is evenly distributed in the duct, and can vary depending on many system factors, including the size of the duct, individual exhaust gases, and absorbent flow rate. This distance can be, for example, about 4 to 5 feet. The conduit 15 defines the flow path of the exhaust gas leaving the industrial process (usually at 17 in Figure 4), as previously described. The catheter 15 is shown as a rectangular cross-section in FIG. 4, but those skilled in the art can easily adapt the absorbent injection assembly to match a catheter having another cross-sectional shape (for example, a circular cross-section).

A perspective view of the first version of the improved absorbent injector device of the present invention is shown in FIG. 1. The injector includes a spray gun 11 including a cylindrical tube having an inlet 19, an outlet 21, an outer 23 and an inner 25, the inner containing a central channel for the absorbent injector and defining an axial centerline 27 of the spray gun 11. The aforementioned absorbent composition (such as slaked lime) is transported through the inside of the absorbent spray gun by pressurized carrier gas, which is a practice in the industry.

As also shown in Figures 1 and 2, two curved injector pipes or curved nozzles 29, 31 surround the outside of the absorbent spray gun 11 and extend in the longitudinal direction substantially parallel to the axial centerline 27 for the main part of their respective lengths ("L" in Figure 2), terminating in the curved end region ("e" in Figure 2). The curved injector pipes each have inlets 33, 35, central holes 37, 39, and outlets 41, 43 for distributing compressed air. As will be understood in relation to FIG. 2, the curved nozzles 29, 31 are angled toward the axial centerline 27 of the absorbent spray gun 11 at a preselected angle that can be in the range of about 0 degrees to about 120 degrees in most cases. In the example shown in FIG. 2, the two nozzles 29, 31 point exactly to the center line 27 and point to each other, forming an angle of 0 degrees, whereby the nozzles directly collide with each other. However, it should be understood that the outlets 41, 43 of the nozzles 29, 31 can also be oriented in one direction or the other relative to the central axis 27 to provide a tangential or partially tangential air flow relative to the central axis 27, and enter therefrom. The absorbent passes through the flow path of the center channel (25 in Figure 1) of the spray gun. It should also be noted that the curved shape of the nozzle is not restrictive to the present invention and other nozzles of different shapes can be provided, as long as the outlets of the nozzles point to the longitudinal axis 27 of the spray gun 11.

Each of the air nozzles 29, 31 communicates with an air supply line (for example, the line 45 in FIG. 2), which in turn communicates with a compressed air source (not shown). The curved injector pipes or curved nozzles 29, 31 are arranged so that the air discharged from the outlets 41, 43 is dispersed in the flow path of the absorbent leaving the central channel of the absorbent spray gun 11 (25 in Figure 1). The absorbent composition discharged from the outlet end of the injector and entering the inside of the duct (17 in Figure 4) reacts with the acid gas or other harmful compounds in the exhaust gas, thereby reducing the concentration of acid gas or these harmful compounds in the exhaust stream . As discussed above, the absorbent composition may be selected from, for example, the group consisting of hydrated lime, quicklime powder, powdered activated carbon, clay and other modified or unmodified minerals, trona, and sodium bicarbonate Or a mixture thereof.

For typical equipment, the absorbent composition will generally have a mass flow rate in the range of about 1 to 20,000 lb/hr. For typical industrial equipment, the absorbent composition in the central channel of the absorbent spray gun will generally withstand a compressed air flow rate in the range of about 5 to 500 scfm and a compressed air pressure in the range of about 0.5 to 200 psig.

As will be understood from FIGS. 1 and 2, the first version of the injector device of the present invention has curved nozzles 29, 31 extending from a common manifold 47. The dotted lines in FIG. 2 show the holes 37 and 39 in the manifold 47 that are joined to the pipes of the common air supply line 45. The nozzles 29 and 31 can be press-fitted into the holes 37 and 39 of the manifold or fixed to the holes 37 and 39 by welding or screwing. However, as shown in Figure 3, the presence of a manifold is not strictly required. In the type of injector device shown in FIG. 3, there are four curved pipes 49, 51, 53, 55, which are equally spaced around the cylindrical spray gun 57. The pipes are joined by a common pipe part 59 which in turn communicates with the air supply line 61.

The bent pipes 49, 51, 53, 55 are attached to the spray gun body 57 by positioning welding or by any other convenient means. The material of the curved pipe can be any metal strong enough to withstand the exhaust gas environment in the duct 17.

In any of the embodiments of the absorbent injection assembly presented in this disclosure, the nozzle, spray gun, manifold or any other part of the material used for the absorbent injection assembly should generally be resistant to corrosion in the environment in which it is used. And in particular, it should be resistant to corrosion when exposed to acid gases. Suitable construction materials include, for example, any material that can reliably withstand the temperature and pressure used in the exhaust gas duct environment, such as metal, such as carbon steel, stainless steel, or brass.

In one case, the curved pipe and air supply line were made from 316 grade stainless steel pipe. The maximum temperature rating of the particular material selected should be as high as approximately 1200°F. In one device, the absorbent spray gun has a cylindrical body with a length in the range of 6 to 240 inches and an inner diameter in the range of 1 to 6 inches. Although only two injector pipes are shown in Figures 1 and 2 for ease of illustration, it should be understood that there may be more pipes, such as four equally spaced pipes. In some equipment, up to about 20 replaceable curved injector pipes can be installed around the cylindrical absorbent spray gun body. The curved injector pipes have a length in the range of about 0.25 to 6 inches and a length of about 0.1 to 2 inches. Inner diameter within inches. In some cases, it may be desirable to temporarily or permanently cover the selected outlet of the injector tube to further adjust the collision angle achieved.

It will be understood from Figures 1-3 that the specific angle configuration of the curved pipes and the air outlets (such as the outlets 41 and 43 in Figure 2) determines the type of dispersion achieved. Therefore, in the case where the nozzles are oriented at an angle of 0 degrees, they will directly collide with each other. However, other angular orientations (ie, angles greater than 0 degrees) will cause the air discharged from its outlet to disperse radially into the duct in a tangential, edge-to-edge direction relative to the absorbent composition leaving the central channel of the absorbent spray gun. The specific configuration of the air nozzles directs the collision air to the exhaust absorbent stream at a specific selected angle, thereby allowing further penetration of the exhaust gas duct and improved pollutant reduction and neutralization.

The flow rate of the carrier gas in the spray gun and the amount of absorbent introduced into the exhaust gas duct can vary depending on various system factors, including, for example, the flux of the exhaust gas to be treated, the concentration of acid gas therein, and the gas to be treated The target acid gas concentration, absorbent type, absorbent retention time and the like. Similarly, the number of absorbent injection assemblies used to supply absorbent (such as slaked lime) to the exhaust gas duct can vary depending on the size of the gas duct. The amount of absorbent injected into the assembly should be selected to allow the absorbent to fully contact all acid gases and/or harmful compounds in the exhaust gas duct, thereby neutralizing acid gases and/or capturing other harmful compounds, such as heavy metals, mercury and/ Or dioxane. In addition to the size of the duct, the amount of absorbent injection assembly used can also depend on factors such as flue gas temperature, acid gas content and the residence time of the exhaust gas in the exhaust duct.

As discussed in the previous technical section, exhaust gases that are treated to reduce their pollutant content can be formed in many industrial processes. Exhaust gas can be the gas produced in the operation of (for example) the following: waste incinerators, sulfuric acid plants, non-coal-fired power plants (such as oil-fired power plants), large diesel generators, boilers, kilns (bricks or ceramics) ) Or kiln (lime or cement). The absorbent injection assembly of the present invention is particularly suitable for treating flue gas generated during coal-fired power generation. In coal-fired power plants, the exhaust gas duct into which the absorbent (such as slaked lime) is introduced can be a boiler exhaust duct, a duct downstream of any catalytic process (such as selective catalytic reduction), one or more of the upstream of the electrostatic precipitator. Hot exhaust gas duct. Alternatively, the absorbent can be added at other processing points. As used herein, the phrases "exhaust gas duct" and "exhaust gas" should not be limited to any specific process or any specific process point. In addition, the term "catheter" should not be limited to any specific catheter shape or any specific type of delivery equipment. In some embodiments, the absorbent (e.g., slaked lime) can be added directly to one or more unit operations or to the discharge part of the unit operation itself (e.g., air preheater).

Figures 5A and 5B show the comparison of the following photos of absorbent dispersion: (A) there is no collision with air; and (B) when 25 scfm pressurized to 75 psig air is supplied to the injector device of the method of the present invention When the air nozzle. The absorbent used in this test is hydrated lime. The results shown below were obtained using the following: (1) the injection device shown in Figures 1 and 2; (2) a high temperature camera, and (3) an instant flue gas analyzer. The injection device is installed in the port of an 8 x 8 foot rectangular duct that maintains> 220,000 scfm exhaust gas at a temperature exceeding 520°F. Approximately 300 feet downstream of the device is a flue gas analyzer, which records temperature and gas composition. The high temperature camera is positioned within 10 feet of the injector device. The photo shows a comparison of a normal plume (A) and a modified plume (B), where the size of the modified plume increases and expands. Therefore, the absorbent has better dispersion in a certain volume to capture acid gases or other harmful compounds.

Initially, the flue gas composition data should be recorded for a minimum of 30 minutes without absorbent. Soon after that, the spray gun was used to supply 1000 lb/hr of hydrated lime at a volume flow rate of 5-500 scfm of conveying air. Record the flue gas composition for a minimum of 30 minutes, and capture the image inside the duct (Figure 5A). After the second step, 75 psig compressed air of 25 scfm (referred to as makeup air in Table 1 below) was supplied by means of a spray gun. Record data for 30 minutes and capture intra-catheter images (Figure 5B).

The results in Table 1 below confirm that the use of 5-500 scfm of transport air volume flow rate and 1000 lb/hr of hydrated lime can effectively reduce the SO ₂ concentration by 32%. In addition, the 31% improvement in the length of the absorbent plume provided by the collision air resulted in an additional 18% reduction in the SO ₂ concentration. Table 1 : Absorbent mass flow (lbs/hr) Supplementary air volume flow (scfm) Supplementary air pressure (psig) Absorbent plume length ( inch ) Time average SO ₂ concentration (ppm) 0 0 0 0 311 1000 0 0 13 211 1000 25 75 17 174

Other embodiments of the absorbent injection assembly according to the spirit of the present invention are presented below.

An embodiment of the absorbent injection assembly according to the present invention is schematically shown in FIG. 6. The absorbent injection assembly is provided to the exhaust gas duct 107 and includes a flange 111 carrying an absorbent injection pipe 101 and a nozzle 108 arranged at a relatively short distance from the absorbent injection pipe. The flange 111 closes the opening provided along the exhaust gas duct 107, and is fixed to the exhaust gas duct by a suitable fixing means such as screws or threads and O-rings (not shown) to provide sealing and fastening. The absorbent injection pipe 101 has a hole 102 developed around the longitudinal axis 106, and an inlet 103 connected to a feed line 105, which is supplied by a carrier gas (e.g. air) and is itself connected to a conveying screw 115, which conveys the powder The absorbent is supplied to the feed line 105, so that the absorbent passes through the feed line 105, the absorbent injection pipe 101 and the outlet 104 of the absorbent injection pipe 101 successively into the interior of the exhaust gas conduit by carrier gas transportation.

The nozzle 108 and the absorbent injection tube 101 are fixed to the flange 111 by welding or press-fitting or by appropriate threads and O-rings to provide sealing and fastening. The absorbent injection pipe 101 and the nozzle 108 may also extend through the flange. The nozzle 108 is connected to a dispersion gas supply line 109, which is preferably an air supply line. The nozzle 108, particularly its outlet 110, points to the longitudinal axis 116 of the absorbent injection tube and can form an angle comprised between 0° and 120° with respect to the longitudinal axis. A plurality of nozzles can be arranged on the flange and can be connected to individual air supply lines or to a single manifold connected to the air supply line. The dispersed gas flow passing through the nozzle and directed to the absorbent stream 106 carried by the carrier gas and injected into the exhaust gas conduit provides dispersion of the absorption particles in the exhaust gas conduit, which increases the probability of the absorption particles interacting with the exhaust gas.

Another embodiment of the absorbent injection assembly of the present invention is described with reference to FIG. 7. The difference between the absorbent injection assembly and the assembly shown in FIG. 6 is that the nozzle 108 is arranged against the absorbent injection tube. The nozzle 108 may be welded to the absorbent injection pipe 101.

Another embodiment of the absorbent injection assembly of the present invention is described with reference to FIG. 8. The absorbent injection assembly is provided to the exhaust gas duct 107 and includes a flange 111 carrying an absorbent injection tube 101, a nozzle 108, and a sleeve 112 having an end wall 114 surrounding the absorbent injection tube 101 to form an annular chamber 113 . The flange 111 closes the opening provided along the exhaust gas duct 107, and is fixed to the exhaust gas duct by a suitable fixing means such as screws or threads and O-rings (not shown) to provide sealing and fastening. The flange 111 further closes the annular chamber 113 at the end opposite to the end wall 114 of the sleeve 112. The annular chamber is connected to the nozzle 108 and the air supply line 109. Preferably, a plurality of nozzles 108 are arranged on the end wall 114 of the sleeve 112, whereby the annular chamber 113 is used as a manifold for supplying air from a single air supply line 109 to the plurality of nozzles 108. The nozzle can be fastened to the sleeve by welding or preferably by press fit or by suitable threads and O-rings so that it can be removed and replaced. This assembly structure allows easier machining of separate parts of the assembly and easier replacement of wear parts. Alternatively, the end wall 114 may be machined on the outer wall of the absorbent injection tube instead of being machined on the inner wall of the sleeve.

The absorbent injection pipe 101 has a hole 102 developed around a longitudinal axis 106, and an inlet 103 connected to a feed line 105, which is supplied by a carrier gas and is connected to a conveying screw 115, which supplies the powdered absorbent to The feed line 105 allows the absorbent to pass through the feed line 105, the absorbent injection pipe 101 and the outlet 104 of the absorbent injection pipe 101 successively into the interior of the exhaust gas duct by carrier gas transportation. The absorbent injection tube 101 is fixed to the flange 111 by welding or press fitting or by appropriate threads and O-rings to provide sealing and fastening. The absorbent injection tube 101 may also extend through the flange. The nozzle 108 points to the longitudinal axis 106 of the absorbent injection tube and may form an angle comprised between 0° and 120° with respect to the longitudinal axis. The dispersed gas flow passing through the nozzle and directed to the absorbent stream 106 carried by the carrier gas and injected into the exhaust gas conduit provides dispersion of the absorption particles in the exhaust gas conduit, which increases the probability of the absorption particles interacting with the exhaust gas.

Another embodiment of the absorbent injection assembly of the present invention is described with reference to FIG. 9. The absorbent injection assembly is provided to the exhaust gas duct 107 and includes a flange 111 carrying an absorbent injection pipe 101, a nozzle 108, and a sleeve 112, which surrounds the absorbent injection pipe 101 and has an outer wall fixed to the absorbent injection pipe To form two opposite end walls 114 and 117 of the annular chamber 113. The flange 111 closes the opening provided along the exhaust gas duct 107, and is fixed to the exhaust gas duct by a suitable fixing means such as screws or threads and O-rings (not shown) to provide sealing and fastening. The annular chamber is connected to an air supply line 109 which passes through the flange 111 and terminates in the nozzle 108. Preferably, a plurality of nozzles 108 are arranged on the end wall 114 of the sleeve 112 around the outlet 104 of the absorbent injection pipe, and the annular chamber 113 has a manifold for supplying air from a single air supply line 109 to the plurality of nozzles 108 effect. The nozzle can be fastened to the sleeve by welding or preferably by press fit or by suitable threads and O-rings so that it can be removed and replaced. This assembly structure allows easier machining of separate parts of the assembly and easier replacement of wear parts.

In this embodiment, the sleeve 112 does not extend in the exhaust gas duct along the entire length of the absorbent injection pipe. This sleeve with a shorter length reduces the amount of metal required to manufacture the sleeve, and also reduces the volume of the chamber 113 formed by the outer wall of the sleeve 112 and the absorbent injection tube 101. Alternatively, the opposite end walls 114, 117 may be machined on the absorbent injection tube instead of being machined on the inner wall of the sleeve.

The absorbent injection pipe 101 has a hole 102 developed around a longitudinal axis 106, and an inlet 103 connected to a feed line 105, which is supplied by a carrier gas and is connected to a conveying screw 115, which supplies the powdered absorbent to The feed line 105 allows the absorbent to pass through the feed line 105, the absorbent injection pipe 101 and the outlet 104 of the absorbent injection pipe 101 successively into the interior of the exhaust gas duct by carrier gas transportation. The absorbent injection tube 101 is fixed to the flange 111 by welding or press fitting or by appropriate threads and O-rings to provide sealing and fastening. The absorbent injection tube 101 may also extend through the flange. The nozzle 108 points to the longitudinal axis 106 of the absorbent injection tube and may form an angle comprised between 0° and 120° with respect to the longitudinal axis. The dispersed gas flow passing through the nozzle and directed to the absorbent stream 106 carried by the carrier gas and injected into the exhaust gas conduit provides dispersion of the absorption particles in the exhaust gas conduit, which increases the probability of the absorption particles interacting with the exhaust gas.

Another embodiment of the absorbent injection assembly of the present invention is described with reference to FIG. 10. The absorbent injection assembly includes a flange 111 that carries an absorbent injection tube 101 having a longitudinal axis 116 and a first nozzle 108 that points to the longitudinal axis 116 of the absorbent injection tube 101, wherein the first nozzle 108 extends along the absorbent The injection pipe 101 is fixed. The absorbent injection assembly further includes an air supply line 109' that passes through the wall of the absorbent injection pipe 101 and terminates in an outlet located in the absorbent injection pipe, the nozzle pointing toward the absorbent injection pipe Exit 104.

In any of the embodiments presented herein in conjunction with FIGS. 7 to 9, a nozzle 108 having a shape forming a right angle is presented. However, any other type of shape of the nozzle is possible, provided that the nozzle is oriented to project a dispersed gas flow and encounter the absorbent flow leaving the outlet of the absorbent injection tube. The nozzle may also have a curved shape or a straight shape inclined toward the longitudinal axis of the absorbent injection tube, for example.

In any of the embodiments presented in the form of figures, the outlet diameter of the nozzle is narrower than the outlet diameter of the absorbent injection tube. Compared with the outflow from the absorbent injection pipe, this is advantageous in providing a higher rate of outflow from the nozzle, without the need for relatively high, specifically uneconomical, high air volume outflow from the nozzle.

The first prototype air-enhanced spray gun of the type shown in Figure 1 was used for testing. The spray gun is specially designed to enhance the dispersion of the Ca(OH)2 particles injected into the catheter and thereby improve the efficiency of acid gas capture. The spray gun achieves this enhanced dispersion by colliding the resulting absorbent plume with the secondary air, and although a relatively low amount (<30 scfm) of pressurized air is applied at this time, a significant increase in SO ₂ capture is achieved ( 18%).

To improve on this encouraging result and verify the observations, two additional prototypes were made for testing: a 4-nozzle air booster spray gun and a 3-nozzle air booster spray gun. The nozzle air supply line featuring these spray guns is designed with a larger inner diameter to accommodate significantly more secondary air flow. In addition, the 3-nozzle air booster spray gun makes it possible to distinguish the dispersion of the absorbent caused by (1) secondary air directed to the resulting absorbent plume and (2) secondary air applied from the inside of the resulting absorbent plume. In addition, the nozzle has been modified to have a removable tip with various orifice sizes (ranging from 3/8’’ to 5/8’’) so that the speed of the secondary air can be fine-tuned.

Figure 11 is in the absence of any flue gas treatment device, after flue gas treatment using the conventional absorbent injection device and after flue gas treatment using the absorbent injection device of the present invention, after the exhaust gas passes through the duct Graphical representation of the measured value of SO ₂ concentration. The embodiment of the absorbent injection device of the present invention comprising four air nozzles is connected to the flue gas pipe as described previously. The dimensions and parameters of the test are provided in the following and Table 2:-The diameter of the flue gas pipe of the equipment: 60"-The exhaust gas flow rate is 384 cubic feet/sec (at the injection position)-The exhaust gas temperature is 828 °F (at the injection position) )-The length of the absorbent injection pipeline in the flue gas pipe (from the flange to the outlet of the absorbent injection pipeline): 3 feet-the diameter of the absorbent injection pipeline, inner diameter-2.5", outer diameter-2.9"- The angle between the axis of the air nozzle and the longitudinal axis of the spray gun: 20 degrees-the diameter of the air nozzle is 3/8 inch. Table 2: Detailed spray gun performance results test Low medium feed rate High feed rate Absorbent type Sorbacal ^® H Sorbacal ^® H Absorbent mass flow rate (lbs/hr) 1080 1560 Spray gun type 4- nozzle Nozzle size (inch) 3/8 Flow rate of secondary air of gauge (scfm) 115 Secondary air temperature (°F) 80 Operating back pressure (psig) 90 Actual secondary air flow rate (acfm) 44 Untreated SO ₂ concentration (ppmvd ref. 12% CO ₂ ) 235 237 SO ₂ concentration (ppmvd ref. 12% CO ₂ ) w FGT 168 142 SO ₂ concentration (ppmvd ref. 12% CO ₂ ) w FGT + secondary air 150 126 SO FGT ₂ by the reduction (%) 28 40 Reduced by additional SO _{2 of} secondary air (%) 11 12 Untreated HCl concentration (ppmvd ref. 12% CO ₂ ) 32 31 HCl concentration (ppmvd ref. 12% CO ₂ ) w FGT 8 6 HCl concentration (ppmvd ref. 12% CO ₂ ) w FGT + secondary air 6 4 HCl reduction by FGT (%) 73 81 Reduce by additional HCl of secondary air (%) 31 25

One invention provides many advantages. The present invention is a universal dry absorbent injection system, which includes a modified spray gun that uses compressed air to disperse and spray absorbing particles. The compressed air collides with the absorbent/air mixture when it leaves the spray gun head. This method achieves an improvement in absorbing particle dispersion and therefore acid gas removal. One advantage of the present invention is that it accommodates a series of replaceable air nozzles so that those skilled in the art can select the proper nozzle geometry that provides the best dispersion of the discharged dry absorbent. Both the number and type of nozzles can be changed depending on the FGT conditions.

The existing prior art injector systems have many shortcomings/disadvantages, including the high initial cost and the fact that operation and maintenance costs are high due to dedicated moving parts. Existing systems usually deliver absorbents at low pressure and air velocity, and require a large volume of air flow to achieve sufficient particle dispersion, which may be detrimental to the performance of the particle control device. The existing prior art system cannot adapt to a wide range of catheter conditions and sizes.

On the other hand, the method of the present invention overcomes many shortcomings of prior art systems and provides many unique advantages, including the following facts: a. The injection device does not require moving parts or special materials, and therefore can be manufactured at relatively low cost. b. Compared with systems such as "no spray gun" injector systems, a relatively low air volume can be used to achieve improved absorbent dispersion. The conventional air compressor is suitable for supplying compressed air. c. The equipment occupies a small footprint inside and outside the catheter to adapt to a wider range of catheter sizes. d. The injector is compatible with commercially available parts and accessories, and therefore does not require special components and expertise for routine maintenance.

Although the present invention has been shown in several forms, the present invention is not limited thereby, but is susceptible to various changes and modifications within the scope of the attached patent application.

11: Spray gun/injector/absorbent spray gun/absorbent injection pipe 13: Side wall / exhaust duct wall 15: Exhaust gas duct/duct 17: Conduit/flow path 19: entrance 21: Exit 23: external 25: internal/internal hole 27: Axial centerline/centerline/central axis/projection longitudinal axis/longitudinal axis 29: Curved injector pipe or curved nozzle / curved nozzle / nozzle / air nozzle 31: Curved injector pipe or curved nozzle / curved nozzle / nozzle / air nozzle 33: entrance 35: entrance 37: Center hole/hole 39: center hole/hole 41: Exit 43: Exit 45: pipeline/common air supply pipeline/dispersed gas supply pipeline 47: Shared manifold/manifold 49: curved pipe/nozzle 51: curved pipe/nozzle 53: curved pipe/nozzle 55: curved pipe/nozzle 57: Cylindrical spray gun/gun body 59: Shared tube part 61: Air supply line/dispersed gas supply line 101: Absorbent injection tube/central channel 102: hole/inner hole 103: entrance 104: Exit 105: Feed line 106: vertical axis/center line/absorbent flow 107: Exhaust gas duct 108: Nozzle 109: Dispersed gas supply line/air supply line 109’: Air supply line 110: Exit 111: flange 112: Casing 113: ring room/chamber 114: End Wall 115: conveying screw 116: vertical axis 117: End Wall

Figure 1 is a side view of an embodiment of the improved absorbent spray gun of the present invention, which shows that the cylindrical spray gun body is surrounded by a pair of injector pipes. In this case, the injector pipes are fed by a common manifold, The common manifold itself is connected to the air source via the main air supply line. Figure 2 is a partial side and cross-sectional view of the spray gun of Figure 1. Figure 3 is a perspective view of an alternative embodiment of the improved spray gun of the present invention, in which the cylindrical spray gun body is surrounded by a plurality of injector pipes, and the injector pipes themselves are connected by a common pipeline which is connected by the main air supply pipeline Feed. FIG. 4 is a simplified diagram of a flue gas treatment equipment for implementing the flue gas treatment process of the present invention. The equipment has an improved spray gun configuration as shown in FIG. 1. Figures 5A and 5B are photos taken with a high-temperature camera installed in the port of the exhaust duct. They compare the dispersion of the absorbent in the following items: (A) there is no collision with air; and (B) when 25 scfm is pressurized When air up to 75 psig is supplied to the curved injector pipe of the device of the present invention. Figure 6 is an absorbent assembly of the present invention was charged to another schematic cross-sectional view of one embodiment, the absorbent is injected to the exhaust gas duct assembly is provided and wherein the absorbent assembly comprises injection having a longitudinal axis of the absorbent carries injection The tube and the flange of the nozzle pointing to the longitudinal axis of the absorbent injection tube, where the nozzle is at a short distance from the absorbent injection tube. FIG 7 based absorbent assembly of the present invention was charged to another schematic cross-sectional view of one embodiment, the absorbent is injected to the exhaust gas duct assembly is provided and wherein the absorbent assembly comprises injection having a longitudinal axis of the absorbent carries injection The tube and the flange of the nozzle pointing to the longitudinal axis of the absorbent injection tube, where the nozzle is fixed along the absorbent injection tube. Figure 8 is a schematic cross-sectional view of another embodiment of the absorbent injection assembly of the present invention, the absorbent injection assembly is provided to the exhaust gas duct and wherein the absorbent injection assembly includes carrying an absorbent injection having a longitudinal axis The tube and the nozzle pointing to the longitudinal axis of the absorbent injection tube and the flange of the sleeve, the sleeve forms an annular chamber around the absorbent injection tube and has a side wall on which the nozzle is mounted and opposite side walls attached to the flange. 9 based absorbent assembly of the present invention was charged to another schematic cross-sectional view of one embodiment, the absorbent is injected to the exhaust gas duct assembly is provided and wherein the absorbent assembly comprises injection having a longitudinal axis of the absorbent carries injection The tube and the nozzle pointing to the longitudinal axis of the absorbent injection tube and the flange of the sleeve. The sleeve has two opposite side walls fixed to the absorbent injection tube to form an annular chamber surrounding the absorbent injection tube, and the nozzle and The air supply line is connected to the annular chamber. The present invention is based absorbent 10 injection cartridge of another schematic cross-sectional view of one embodiment, the absorbent is injected to the exhaust gas duct assembly is provided and wherein the absorbent assembly comprises injection having a longitudinal axis of the absorbent carries injection Tube and the flange of the nozzle pointing to the longitudinal axis of the absorbent injection tube, wherein the nozzle is fixed along the absorbent injection tube, the absorbent injection assembly further includes an air supply line intersecting the side wall of the absorbent injection tube, the assembly further includes The nozzle in the absorbent injection pipe is directed to the outlet of the absorbent injection pipe. Figure 11 shows the exhaust gas passing through the duct without any flue gas treatment device, after flue gas treatment using the conventional absorbent injection device, and after flue gas treatment using the absorbent injection device of the present invention The graph of the measured value of SO ₂ concentration afterwards.

101: Absorbent injection tube

102: hole

103: entrance

104: Exit

105: Feed line

106: vertical axis/absorbent flow

107: Exhaust gas duct

108: Nozzle

109: Dispersed gas supply pipeline

110: Exit

111: flange

115: conveying screw

116: vertical axis

Claims (16)

An absorbent injection assembly for injecting absorbent into exhaust gas ducts (15, 107), the absorbent injection assembly includes: The absorbent injection tube (11, 101), which includes an inner hole (25, 102) with a longitudinal axis (27, 106), an inlet (19, 103) and an outlet (21, 104), the absorbent injection tube (11 , 101) is configured to transport the absorbent through it by carrier gas, so that the absorbent is injected into the exhaust gas duct (15, 107), so that the absorbent flow is parallel to the absorbent injection pipe (11, The axial component of the longitudinal axis (27, 106) of 101) leaves the outlet (21, 104); and At least one nozzle (29, 49, 108), which has an inlet configured to be coupled to the dispersion gas supply line (45, 61, 109) and the outlet (21) provided in the absorbent injection pipe (11, 101) , 104) near the outlet (41, 43, 110), the nozzle (29, 49, 108) is oriented toward the longitudinal axis (27, 106) of the absorbent injection pipe (11, 101), so as to disperse the gas The flow is projected onto the absorbent flow leaving the outlet (21, 104) of the absorbent injection pipe (11, 101), Wherein the absorbent injection assembly effectively provides an increased dispersion of the absorbent in the exhaust gas duct. Such as the absorbent injection assembly of claim 1, wherein the absorbent injection assembly further comprises: a flange (111) configured to close the opening provided on the exhaust gas duct (15, 107), the flange (111) Carry the absorbent injection tube (11, 101) and the at least one nozzle (29, 49, 108) to inject the absorbent into the tube (11, 101) and the at least one nozzle (29, 49, 108) is installed on the exhaust gas duct (15, 107). Such as the absorbent injection assembly of claim 1, wherein the absorbent injection assembly includes at least two nozzles (29, 31, 49, 51, 53, 55). Such as the absorbent injection assembly of claim 1, wherein the at least one nozzle (29, 49, 108) is fixed to the absorbent injection tube (11, 101). Such as the absorbent injection assembly of claim 1, wherein the absorbent injection assembly further comprises: a sleeve (112) surrounding the absorbent injection tube (11, 101). Such as the absorbent injection assembly of claim 5, wherein the at least one nozzle (29, 49, 108) is fixed on the sleeve (112). For example, the absorbent injection assembly of claim 6, which further includes a hole extending from the first end connected to the dispersed gas supply line (45, 61, 109) and connected to the nozzle (29, 49, 108) ) At least the second end. The absorbent injection assembly of any one of claims 5 to 7, wherein the sleeve (112) has a side wall that forms an annular chamber (113) around the absorbent injection tube (11, 101), and wherein the at least one Nozzles (29, 49, 108) are connected to the annular chamber (113), and the annular chamber (113) is configured to be connected to the dispersed gas supply line (45, 61, 109). Such as the absorbent injection assembly of any one of claims 1 to 7, wherein the at least one nozzle (208) relative to the longitudinal axis of the absorbent injection tube (11, 101) is comprised between 0 degrees and 120 degrees The angle between. Such as the absorbent injection assembly of claim 2, wherein the absorbent injection tube (1) has a cylindrical body extending from the flange (111) to the outlet (21, 104), and the cylindrical body has a diameter between 6 inches and Length within 240 inches and inner diameter within 1 inch to 10 inches. Such as the absorbent injection assembly of any one of claims 1 to 7 and 10, wherein the at least one nozzle (29, 49, 108) includes a hole (37) extending from the inlet to the outlet (41, 43, 110) , 39), the hole (37, 39) has an inner diameter in the range of about 0.1 inch to 2 inches, and the hole (37, 39) extends from the outlet (21) of the absorbent injection pipe (11, 101) , 104) extends axially and has a length ranging from about 0.25 inches to about 6 inches. A method for reducing the amount of harmful compounds in exhaust gas passing through an exhaust gas duct (15, 107), the exhaust gas duct having an inner wall defining a flow path (17) passing through the exhaust gas duct (15, 107), the method comprising The following steps: Provide the absorbent injection assembly of any one of claims 1 to 11; Inject the absorbent into the exhaust gas duct (15, 107) so that the absorbent flow leaves the outlet (21, 104) with an axial component parallel to the longitudinal axis (27, 106) of the absorbent injection pipe (11, 101); and Generate a gas flow through at least one nozzle (29, 49, 108) so as to project the dispersed gas flow onto the absorbent flow leaving the absorbent injection tube (11, 101), thereby resulting in The dispersion of the absorbent flowing out of the outlet (21, 104) of (11, 101) increases. A method for reducing the amount of harmful compounds in exhaust gas passing through an exhaust gas duct (15, 107), the exhaust gas duct having an inner wall defining a flow path (17) passing through the exhaust gas duct (15, 107), the method comprising The following steps: An absorbent injection assembly for injecting absorbent into the exhaust gas duct is provided. The absorbent injection assembly includes: The absorbent injection tube (11, 101), which includes an inner hole (25, 102) with a longitudinal axis (27, 106), an inlet (19, 103) and an outlet (21, 104), the absorbent injection tube (11 , 101) is configured to transport the absorbent through it by carrier gas, so that the absorbent is injected into the exhaust gas duct (15, 107), so that the absorbent flow is parallel to the absorbent injection pipe (11 , 101) the axial component of the longitudinal axis (27, 106) leaves the outlet (21, 104); At least one nozzle (29, 49, 108), which has an inlet configured to be coupled to the dispersion gas supply line (45, 61, 109) and the outlet (21) provided in the absorbent injection pipe (11, 101) , 104) near the outlet (41, 43, 110), the nozzle (29, 49, 108) is oriented toward the longitudinal axis (27, 106) of the absorbent injection pipe (11, 101), so as to disperse the gas The flow is projected onto the absorbent flow leaving the outlet (21, 104) of the absorbent injection pipe (11, 101); and A flange (111) for closing the opening provided on the exhaust gas duct (15, 107), the flange (111) carries the absorbent injection pipe (11, 101) and the at least one nozzle (29, 49, 108) to install the absorbent injection pipe (11, 101) and the at least one nozzle (29, 49, 108) on the exhaust gas duct (15, 107), Connect the absorbent injection pipe (11, 101) to the feed line supplied by carrier gas and absorbent; Provide dispersed gas via the dispersed gas supply line (45, 61, 109); and Provide the absorbent composition and at the same time provide the carrier gas flow in the feed line, Wherein the dispersed gas flow provided by the at least one nozzle, in particular air, causes the dispersion of the absorbent composition flowing out from the outlet of the absorbent injection pipe to increase, thereby making the absorbent composition and the exhaust gas The efficiency of the resulting interactions between the harmful compounds present in the gas is increased, thereby reducing the concentration of harmful compounds in the exhaust gas. Such as the method of claim 12 or 13, wherein the absorbent is selected from the group consisting of hydrated lime, quicklime powder, powdered activated carbon, clay, trona, sodium bicarbonate, and mixtures thereof. Such as the method of claim 12 or 13, wherein the absorbent is introduced into the exhaust gas conduit (15, 107) at a mass flow rate in the range of about 1 lb/hr to 20,000 lb/hr, and the volume flow rate is from 5 scfm to Conveying gas drive within 500 scfm range. The method of claim 12 or 13, wherein the absorbent stream ejected from the absorbent injection tube is subjected to compressed air with a flow rate in the range of about 1 scfm to 400 scfm and/or a pressure in the range of about 0.5 psig to 200 psig Compressed air.

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