dry scrubber diagram
Dry scrubbers, as the name implies, do not use water or any liquid substances to carry out the scrubbing process. A scrubber is a waste gas treatment installation in which a gas stream is brought into intensive contact with a liquid, with the aim of allowing certain gaseous components to pass from the gas to the liquid. Some of these materials neutralize harmful pollutants in the stream through a chemical reaction, while others cause a material to react and turn into a different substance. Halogen addition could also affect fly ash to a lesser degree. smart vacuum cleaner. Dry scrubber systems spray a collection of dry reagents into the exhaust. FIG. The humidifying efficiency of the scrubber may be expressed as: μ h = (t 1 - t 2) / (t 1 - t w) 100% (1) where. However, washing the FGD gypsum, as is commonly done for wallboard grade gypsum, would remove most of the halogens. smart hair dryer. [Online]. Dry scrubbers, as the name implies, do not use water or any liquid substances to carry out the scrubbing process. In this process, hydrated lime, limestone, or dolomite and water are intimately mixed with flue gas in a dedicated reaction chamber, which is the fuel-firing bed. WET EGCS Scrubber design and installation is a complex and time-consuming series of investigations and decisions because each ship requires a bespoke solution. FIG. Where abrasion is considered severe in FGD, 60 durometer natural rubber is the proper selection. MIKROPUL WET SCRUBBERS MikroPul has been a pioneer world-wide in providing wet scrubbers to solve air pollution control problems for over 40 years. They are primarily implemented for removal of acid from gas. The highest removal efficiencies are achieved by wet scrubbers, greater than 90% and the lowest by dry scrubbers, typically less than 80%. Spray dryers remove acid gas in a two-stage system that consists of a spray dryer absorber (SDA) followed by particulate control. Spray dry scrubbers were first installed in the early 1980s in the United States . The heat of the flue gas evaporates the water present in the slurry, leaving fine, dry particles of salt, fly-ash and excess alkali to be collected in the fabric filter (other forms of filter medium, including ceramic and metallic, are possible). Testing of wet scrubber additives began 10 years ago in the United States with varied success (Blythe, 2006, 2007; Ghorishi et al., 2005). Fabric filters used in conjunction with a spray dryer scrubbing system have not been susceptible to failure on WTE facilities. While some reaction occurs as the sorbent is transported with the gas, further neutralization occurs in the dust cake on the filter bags or ceramic elements in the baghouse. Spray Dry Scrubber. Typical nozzle scrubber … Catalytic reduction, activated carbon, and dry sorbent injection are employed to reduce NOx and remove heavy metals, dioxins/furans, and PM, respectively. The benefits are often sung anecdotally but haven't been studied significantly. In one documented case, gypsum produced from a power plant using a wet scrubber reemissions additive was tested at a commercial wallboard plant, with no noted adverse effects on the wallboard production process (Sanderson, Blythe, & Richardson, 2006). Type VVO scrubbers can be supplied to operate at pressure drops from 8” … A dry gas scrubber, unlike the wet scrubber, does not saturate the flue gas stream that is being treated with moisture. 5 is a flow diagram of example operations for gas treatment using a dry scrubber system with bacteria therein. The absorber is a fluidized bed of solids suspended by flue gas At low loads clean gas is recirculated . Toluol ist ein aromatischer Kohlenwasserstoff, häufig ersetzt es als Lösungsmittel das giftige Benzol. Chlorobutyl rubber of 60 Shore A durometer is used for the FGD absorber, associated demister internals, and other component piping. In selecting a rubber lining for a pipe, either for recycled slurry, reagent feed, gypsum dewatering, or filtrate systems, one must take into account the volume flow, percentage of solids, and particle size to make the proper choice of the rubber compound. Dry brushing is exactly what it sounds like brushing your skin with a dry brush. Command Hub, Control panel replacement. US20140369909A1 US14/308,184 US201414308184A US2014369909A1 US 20140369909 A1 US20140369909 A1 US 20140369909A1 US 201414308184 A US201414308184 A US 201414308184A US 2014369909 A1 US2014369909 A1 US 2014369909A1 Authority US United States Prior art keywords ph media dry chemical scrubber elements Prior art date 2013-06-18 Legal status (The legal status is … Cyclones, fabric filter bags, and ESP remove PM and fly ash from the flue gas. Wet-limestone scrubbing is a … Many problems, both mechanical and process, can occur. 13 4-1 Simplified flow diagram of flyash scrubbers, Four Corners Plant (Arizona Public Service) 21 4-2 Flow diagram of combined particulate-SCL scrubber system at Lawrence No. For wet FGD systems that have hydrocyclones for primary dewatering, the fine solids in the overflow stream can have as much as 10 times the mercury concentration of the larger particles in the underflow (EPRI, 2004a). Scrubber driers. Product care. A dry scrubber or dry scrubber system is one type of scrubber that is used to remove harmful materials from industrial exhaust gases before they are released into the environment. For the first type, the dry absorber utilizes a fluidized bed—either bubbling bed or circulation bed. Semi-dry scrubbers spray the flue gas with an aqueous absorption agent as opposed to saturating it, and dry scrubbers pass the flue gas through an agent that is in the form of a fine, dry powder, such as lime. Troubleshooting. Visit https://goo.gl/mBWynh to view the full video and purchase access to our other Pulping courses. Some will simply neutralize a harmful material through a chemical reaction. Generally speaking, to date, dry scrubbing installations have tended to be on a smaller scale that wet scrubbing, although larger installations are being built. This period included the start-up/shake-down of the facility. In the gas cooling system, emission gases are cooled to make it easier to remove pollutants and other toxins from the gas. The collection efficiency of the Ducon Oriclone Venturi Scrubber is a function of the pressure drop across the throat which, in turn, is a function of the quantity of submicron particulate matter suspended in the gas stream. •Avoid any water and /or liquids around the vicinity of the machine when in use or not in use to prevent any accidental injury. Dry Scrubber. Command Hub, Control panel replacement. A 40 durometer natural rubber gains five times the amount absorbed by a 60 durometer lining. Scrubber systems (e.g. •Check the cord and plug for damage before use. Additional technologies have been developed to enhance the percentage oxidation of mercury in flue gas at the FGD inlet, and to limit reemission of mercury in the absorber. This is due primarily to the higher unit reagent costs for dry scrubbing . A scrubber is a waste gas treatment installation in which a gas stream is brought into intensive contact with a liquid, with the aim of allowing certain gaseous components to pass from the gas to the liquid. One is that higher mercury concentrations may report to the FGD solids. An FGD system and its auxiliary equipment provide a wide range of parameters, which must be evaluated to tailor the proper lining system for the required process conditions. The particulates are captured in the series of filter bags as the flue gas passes through them and then air is blown in the opposite direction to clean the filters and collect the dust. All scrubber systems require a treatment bypass for when the ship is operating without the need to use the scrubber. The injection rates of slurry and dilution water are controlled by signals from the in-stack CEMs and the SDA outlet temperature. The most common oxidation technology used for mercury control is halogen addition. Such a regenerating process is mentioned in US Pat. FIG. Dry scrubbers are primarily used to abate acidic gases, like those associated with acid rain. Dry Scrubber Users Association is a non-profit, non-stock corporation formed in 2008. The number of scrubbers installed on ships has increased significantly over the last years. Table 3.4 depicts lead and cadmium EP Toxicity analysis (20) of ash obtained from an operating waste-to-energy facility (700 TPD) located in New England. Spray dry scrubbers are the second most popular method, with an efficiency as good as that of wet scrubbers, if … A venturi scrubber is designed to effectively use the energy from a high-velocity inlet gas stream to atomize the liquid being used to scrub the gas stream. Dry chemical scrubbers convert, through chemical reaction, acid gases into other compounds. First, gas cooling must be done to prepare exhaust gases. As shown in the diagram above, EtO gas enters at the bottom of the column, and flows upward through the packing while the scrubbing liquid flows downward by gravity. Venturi Scrubber Advantages. This method of collection usually provides removal efficiencies of about 99 per cent. These include. Chellappa Chandrasekaran, in Anticorrosive Rubber Lining, 2017. Wet scrubber: This uses an excess of slurry and produces a wet waste stream. Here you can download discontinued product information, end-user guides, parts lists,service manuals and more. μ h = scrubber humidifying efficiency (%) t 1 = initial dry bulb temperature (o C) t 2 = final dry bulb temperature (o C) t w = initial wet bulb temperature (o C) Scrubber Efficiencies. The SDA has also proven successful in capturing mercury (Hg) if the mercury has been previously reacted with activated carbon in halogenated or neat form . Wet ESP technology was previously discussed as an SO3 control technology. DRY EGC technology uses sodium bicarbonate as an absorbent to clean ship exhaust gas. ABB Flakt developed one such system in Malmo, Sweden; others also have developed similar systems. APC equipment employed in the syngas cleaning and conditioning stages and flue gas treatment of waste gasification and pyrolysis plants typically include scrubbers, cyclones, fabric filter bags, and ESPs. Scrubbing is also referred to as absorption. Upon operating the dry scrubber at design conditions, the lead (0.40–0.50 mg/l) and cadmium (0.20–0.53 mg/l) dropped to acceptable levels. This neutralizes the pollutants in the gas. Copyright © 2020 Elsevier B.V. or its licensors or contributors. Process description. Additional removal techniques include catalytic reduction, dry sorbent injection, and flue gas condensation. The main impact of scrubber additives will be increased mercury concentrations in the FGD solids, if the additive is effective. The final disadvantage to using a dry scrubber is that they cannot remove all contaminants from the gas. The fly-ash, salts and a minimal quantity of excess free agent are then transported from the fabric filter hoppers by mechanical or pneumatic conveying systems to a solids storage silo. ESP has a limited efficiency in removing small particles and is often installed together with fabric filter bags to meet stringent emissions limits . The mercury precipitated with the additive should be concentrated in fine particles. Alkalis that contribute to slagging in waste thermal treatment systems are potassium (K), Na, Cl, and silica. The scrubber market is highly dynamic at the moment, due to the recent tightening of the SECA fuel sulphur limits. Power facilities are the largest generators of SO2, which may cause acid rain. dry scrubbers, regenerable processes, and sorbent injection systems. The reduction of the lead and cadmium levels of the resultant ash by one to two orders of magnitude cannot be attributed to just dilution by bottom ash addition; rather the pozzolanic reaction reduced the resultant heavy metals from leaching under the EP Toxicity Test. Dry glycol flows down the tower from the top, from tray to tray or through packing material. Some disadvantages of the semi-dry scrubber system are: Potential for clogging and erosion of the injection nozzles due to the abrasive characteristics of the slurry; Potential for slurry or particle build upon walls of the SDA and ductwork; Potential for blinded bags if slurry moisture does not evaporate completely; and. 6 is a flow diagram of example operations for gas treatment using a combined scrubber system. waste incineration Wet Scrubbers, DIFF, Carbon H2S & VOC removal PM & hydrocarbon removal Venturi + Packed Tower + heat exchanger Recent Projects. High temperature excursions are also not likely and the addition of the alkaline reagent results in more efficient filtering characteristics and lower corrosion potential. The final step is using a fabric filter to capture the used scrubbing powder as the cleaned gas exits the scrubbing chamber. This design provides utilization of reagents once. In this case the wet ESP wastewater would not directly impact CCPs, but it could increase the mercury, selenium, and other trace element concentrations in the FGD wastewater and/or gypsum. VIEW MORE. A dust collector is a system used to enhance the quality of air released from industrial and commercial processes by collecting dust and other impurities from air or gas. The factors that control how mercury partitions between phases are not completely understood. Activated carbon and alkali sorbents such as lime and NaOH are injected into flue gas to remove volatile heavy metals and acid gases . 2 provides a conceptual block diagram of a circulating dry scrubber (CDS). HCl is scrubbed with NaOH in a Vertical or Horizontal Packed Bed Scrubber according to the reaction: HCl + NaOH NaCl + H 2 O. Raw and fresh reagents are charged continuously to the absorber to compensate for the discharge losses. Dry scrubbers do not use any liquids in process but exhaust gases are cleaned with hydrated lime-treated granulates. However, significant halogen removal with the fly ash would not be expected. For smaller utility boilers, the simplicity and lower capital costs of dry scrubbing make it an attractive alternative for higher sulfur coals. Cyclones consist of a cylindrical chamber and remove PM from the flue gas via inertia. Generally, this is done by introducing a series of dry reactants to exhaust gas at high speeds. MODA ONE. Halogen salts such as calcium chloride (CaCl2), calcium bromide (CaBr2), or potassium iodide (KI) can be added to the coal as a means of supplementing the coal chlorine content. wet dry vacuums. FGD absorber service life histories confirm that the chlorobutyl linings give trouble-free service when correctly applied and cured. However, corrosion continues to prevail in the system. FGD is a set of technologies used to remove SO2 from exhaust flue gases of fossil-fuel power plants, and from the emissions of other sulfur oxide-emitting processes. Blythe, in Coal Combustion Products (CCP's), 2017, The effectiveness of mercury coremoval in an FGD system is generally dependent on the percentage of the mercury in the flue gas that is in an oxidized form. When sulfur dioxide mixes with moisture in clouds, it creates acid rain. Combined SO 2/NO x processes have a small share, and the trend is not expected to change. The slurry moisture evaporates from the heat of the combustion gases, thereby controlling the inlet temperature to the baghouse. Scrubbers are used to remove acid gases, such as HCl and SO2, and alkaline gases from the flue gas. Richard W. Goodwin Ph.D., P.E., in Combustion Ash Residue Management (Second Edition), 2014. Maintenance costs are also reduced; Flue gas temperature above the dew point resulting in no visible condensation plume; Flue gas reheating not generally required for plume rise; High removal efficiencies for PM, including very fine particles and trace metals; and. A dry system employs pellets of hydrated lime to remove sulphur. 5 is a flow diagram of example operations for gas treatment using a dry scrubber system with bacteria therein. The oxidized form of mercury is water soluble and can be removed in wet or dry scrubbers, while the other predominant form, elemental mercury, is not. They are more commonly used on land-based installations and not so common for marine use. From typical ferry ships, we can save 500t CO2 emissions per year per ship. The reagents used are normally dry hydrated lime instead of the lime slurry used in the semidry scrubber system. Since such solutions are relatively expensive, attempts have been made to regenerate the sodium-based scrubbing liquors by reacting, or causticizing, the spent scrubbing solutions with an alkaline earth compound, such as lime or limestone. The second design utilizes a reagent injection system to inject the reagents directly into the combustion product gas stream, either in a separate chamber or in the hot gas duct. The dry scrubbing process, although developed for over 30 years, has more recently become a key unit for the treatment of acid gases, particularly in the treatment of flue gases from incineration and combustion processes. That substance then falls out of the gas stream or is caught in a particle screen. Dry scrubbers are used mainly to remove acid gases from combustion sources. Mercury removed by wet ESPs would be present in the wastewater from the process, and the wastewater is most commonly used as part of the water makeup to the upstream wet FGD system. Also within the system is a material component that aids in the removal of the reaction product, which is the dry sorbent bound to the pollutant. chemical scrubbers, gas scrubbers) are a diverse group of air pollution control devices that can be used to remove some particulates and/or gases from industrial exhaust streams. SO2 emission is a particularly acute problem in the electric power-generating industry where large quantities of coal are burnt. Although this type of design has high removal efficiency, the high initial capital costs and the operation complexity limit its application. This is good news. DSI has also been used for acid gas reduction as a form of dry scrubber. Type of Technology: Removal of air pollutants by inertial and diffusional interception. The lime pellets absorb sulphur and transform to gypsum. Typically the process is used to treat acid gases in a spray dryer, coupled with a pulse-jet fabric filter. •Insert 3-prong plug on power cord directly into matching grounded receptacle. However, how they do it is slightly different. The SDA is particularly effective at capturing HCl and other halogen-based acids, driving the reactions largely in aqueous form and then drying the resulting CaSO4 or CaCl2 to powders that can be captured in the baghouse downstream of the SDA reactor. This neutralizes the pollutants in the gas. As the gas passes through the cake on the filter bags, a further reduction of the acid gas occurs as it reacts with the excess reagent in the filter cake; purified exhaust gases are then vented through a chimney equipped with a continuous monitoring system. Institute.unido.org, 2018. Scrubber additives were first used in Europe to prevent reemissions from wet scrubber systems installed on municipal waste burning plants, and they have reportedly been used for this purpose in some European coal-fired plants. In this system, equipment such as absorber towers, demister supports, gas outlets, recycle and process piping, process tanks, and agitators are highly exposed to corrosive and abrasive environments. When the, The Development of Postcombustion Control Technology, Coal-Fired Electricity and Emissions Control, in the second stage at a pH close to neutral or alkaline. The reagents coated on the filter bags are the only removing mechanism for acid gases removal. Another disadvantage is that the process of scrubbing is expensive. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B978012813473300009X, URL: https://www.sciencedirect.com/science/article/pii/B978008099396600006X, URL: https://www.sciencedirect.com/science/article/pii/B9781437778717100085, URL: https://www.sciencedirect.com/science/article/pii/B9780323443715000104, URL: https://www.sciencedirect.com/science/article/pii/B9780128015759000147, URL: https://www.sciencedirect.com/science/article/pii/B9780080993966000034, URL: https://www.sciencedirect.com/science/article/pii/B9780081009451000034, URL: https://www.sciencedirect.com/science/article/pii/B9780124200388000033, URL: https://www.sciencedirect.com/science/article/pii/B9780128092453000094, URL: https://www.sciencedirect.com/science/article/pii/B9780128127162000054, Combustion fundamentals and energy systems, Fuel Property Estimation and Combustion Process Characterization, Filters and Filtration Handbook (Sixth Edition), Rubber Lining for a Sulfur Dioxide Scrubbing System, A circulating fluidized bed (CFB) involves a scrubbing technology known as a, Flue-gas desulfurization products and other air emissions controls, The effectiveness of mercury coremoval in an FGD system is generally dependent on the percentage of the mercury in the flue gas that is in an oxidized form. •Do not use with an adapter Keep wiring and motor dry. 1500 t/d black liquor dry solids in its recovery boiler. Even though dry brushing has recently gained more popularity on the media as the beauty secret of many celebrities, it’s a technique that has been used for centuries by Scandinavians, Turks, and Russians to eliminate impurities and toxins and maintain healthy skin. Extrapolating from the averages of the Pb and Cd ranges yields fly ash levels of Pb = 31.58 mg/l and Cd = 4.35 mg/l, consistent with other investigators (21). Dry scrubbers are the type most commonly used in plants today, and they utilize a collection of dry substances to remove acidic gases that contribute to acid rain.. Dry gas scrubber is a air pollution control device that is used to remove some particulates and/or gases from industrial exhaust streams. The process can achieve about 95% SO2 removal efficiency. Most of this material that is sprayed into the exhaust is burned off in the heat of the stream or is caught in a filter. Scrubbers – Dry cleaning technology. Schlumberger glycol dehydration processes remove water vapor from natural gas, which helps prevent hydrate formation and corrosion and maximizes pipeline efficiency. Since most FGD scrubber piping encounters very light abrasion, installing chlorobutyl is expected to last in excess of 15 years. Semi-dry scrubbers involve a chemical reaction with a wet slurry, and a dry scrubbing of the gases with dry collection of co-products. The following is a list of the basic parameters that should be considered for designing a rubber lining: Dipak K. Sarkar, in Thermal Power Plant, 2015, A circulating fluidized bed (CFB) involves a scrubbing technology known as a dry scrubber process. Fabric filter bags are the most commonly employed equipment because they have a high particulate removal efficiency for large and small particles. FIG. A high energy scrubber expends the most energy and has a pressure drop of 25 to over 100 inches of water column, which is necessary to remove sub-micrometer particles. The system sprays a collection of dry reagents into an exhaust stream. Owing to their limited removal efficiency, they are employed in facilities as a complement to other flue gas treatment stages. The gas is scrubbed by a countercurrent flow of liquor. The advantage of wet scrubbers is that they are generally less expensive than semi-dry and dry scrubbers; however, the disadvantage is that they produce wastewater that must be treated and discharged. A. Atkins and M. Escudier, A dictionary of mechanical engineering. Venturi Scrubber Diagram. It is in this step that the harmful components are actually removed from the gas. While SO2 removal performance may be improved, droplet drying will slow, and the spray dryer outlet temperature may have to be raised to compensate. The conditions within a scrubber and accompanying installations are very severe, cumulative, and cause corrosion problems for common engineering materials. The differentiating factor between these scrubbers is the environment in which the flue gas is treated. Part Number: 124402-1 $299.00. This can increase the amount of halogen material remaining in dewatered products such as gypsum, which may have limitations by the wallboard manufacturer on the amount of dissolved salts allowed. Note: All concentrations expressed in mg/l. These additive types tend to form an insoluble precipitate or complex with dissolved oxidized mercury. Because of high SO2 removal efficiency the Ca:S ratio (1.2–1.5) of the dry scrubber process is less than that of the sorbent injection system. Additives to the scrubber to limit reemission generally work by rapidly precipitating or adsorbing oxidized mercury from the scrubber liquor to the solid phase, so it will not react with other liquid-phase species and be converted back to the elemental form. Sulfur dioxide (SO2) is a corrosive gas that is created by the oxidation of sulfur-bearing materials such as coals, oil, and natural gas. In many FGD pipe applications, 40 durometer pure gum rubber compounds (i.e., with fewer fillers) give only 3–7 years of service whereas a 60 durometer natural rubber gives 7–10 years of life. This system is best used in small- to medium-sized power plant units where duct sizes are not overwhelming. It is a multiple- or a single-stage system used in the treatment of gas streams by controlling the amount of acidity, particles, toxins, metals and odors before releasing it into the atmosphere. the entire packaged type scrubber factory fitted has to be supplied at site well assembled for its best alignment. A set of standardized P&ID symbols is used by process engineers to draft such diagrams. These combined systems are not susceptible to fires due to the long retention time in the spray dryer and the cooling of the gases. DefendAir® HEPA 500 Air Scrubber 115-volt model WARNING READ AND SAVE THESE INSTRUCTIONS FIRE AND ELECTRIC SHOCK HAZARD Unit must be electrically grounded. For spray dryer-based dry FGD systems, the presence of elevated halogen levels in the flue gas will alter droplet drying characteristics, due to the deliquescent nature of the calcium salts of these halogen acids. An additional benefit is that the high temperature in the scrubber burns off any soot and oily residues. Tennant M20 G/LP Scrubber Sweeper (S/N 008000-up) Model 9016001 Parts Tennant M20 G/LP Scrubber-Sweeper (S/N 000000-007999) 331381 Parts Tennant M30 Diesel Scrubber-Sweeper (S/N 000000-007999) - 9003952 Parts All internal surfaces as subjected to a saturated environment or are in immersion. Dry scrubbers may spray a powder of lime or limestone directly into the furnace, at high temperature, causing granules to become porous or cracked to further improve their absorption capability and capacity. High reagent usage since reagent is not recycled. In general, gasification and pyrolysis produce a lower volume of syngas than WtE facilities; therefore, smaller APC equipment is required in these facilities. The effectiveness of this technology is based on increasing the percentage of the mercury in the flue gas that is in the oxidized form. The main parameter affecting the life of the design is the diffusion of water vapor through the rubber that attacks the metal surface beneath and affects the process temperature. Wet vs Dry Scrubber. While removal efficiency may be relatively low (compared to wet or semi-dry scrubbing), dry scrubbing has a significantly lower cost of capital and is a simpler process. •Make sure machine is on a clean and dry surface area to prevent any accidental . These reagents can have a number of different effects depending on the material they target. Dry Scrubbing System Sistem ini berfungsi menyaring debu dan mengadsorbsi gas fluorida yang berasal dari pot reduksi. But, the Sox emission causes dry and wet precipitations. The exhaust gas is moved through the scrubbing liquid (usually through a chamber) and the liquid is misted through the gas. There are two different designs used for FGD systems: Dry scrubber: This is used to heat up the incoming flue gas to vaporize the liquid in the lime slurry used to scrub the SO2 from the gas, resulting in a dry waste stream. Spray dryers/dry scrubbers are used to control heavy metals. When moderate to light abrasion is encountered, 60 durometer chlorobutyl lining may also be utilized. Instead, dry industrial scrubbers utilize a dry reaction material known as “sorbent”, such as alkaline slurry. K.J. Ducon Venturi Scrubber. Spray dryers inject an alkaline slurry into the gas stream, causing water in the slurry to evaporate resulting in a cooling of the combustion gases. This task is done in three steps: gas cooling, reagent injection, and filtering.First, gas cooling must be done to prepare exhaust gases. Dry scrubbers are also more commonly used than wet scrubbers mainly because they produce comparatively little waste material. These results reflect the range of values obtained from samples taken during the spring of 1987 (April–June). The gas temperature is controlled by the flow rate of the dilution water. A dry scrubber, or dry scrubber system, is a type of pollution control equipment that is designed to remove harmful gases and particulates from industrial exhaust streams. Both systems have the same basic methods of operation and the same final goal; they simply reach them through different materials. Adding sodium-based exhaust gases reduces SO2 emissions by 98%.