Scrubber
Encyclopedia
Scrubber systems are a diverse group of air pollution
control devices that can be used to remove some particulates and/or gases from industrial exhaust streams. Traditionally, the term "scrubber" has referred to pollution control devices that use liquid to wash unwanted pollutants from a gas stream. Recently, the term is also used to describe systems that inject a dry reagent or slurry
into a dirty exhaust stream to "wash out" acid gas
es. Scrubbers are one of the primary devices that control gaseous emissions, especially acid gases. Scrubbers can also be used for heat recovery from hot gases by flue gas condensation
.
There are several methods to remove toxic or corrosive compounds from exhaust gas and neutralize it.
is sometimes the cause for harmful exhaust gas, but, in many cases, combustion may also be used for exhaust gas cleaning if the temperature is high enough and enough oxygen is available.
A wet scrubber
is used to clean air, flue gas
or other gas
es of various pollutant
s and dust
particles. Wet scrubbing works via the contact of target compounds or particulate matter with the scrubbing solution. Solutions may simply be water
(for dust) or solutions of reagents that specifically target certain compounds.
Process exhaust gas can also contain water soluble toxic and/or corrosive gases like hydrogen chloride
HCl or ammonia
NH3. These can be removed very well by a wet scrubber.
Removal efficiency of pollutants is improved by increasing residence time in the scrubber or by the increase of surface area of the scrubber solution by the use of a spray nozzle
, packed towers
or an aspirator
. Wet scrubber
s may increase the proportion of water in the gas, resulting in a visible stack plume, if the gas is sent to a stack.
, does not saturate the flue gas stream that is being treated with moisture. In some cases no moisture is added; while in other only the amount of moisture that can be evaporated in the flue gas without condensing is added. Therefore, dry scrubbers do generally not have a stack steam plume or wastewater
handling/disposal requirements. Dry scrubbing systems are used to remove acid gas
es (such as SO2
and HCl
) primarily from combustion
sources.
There are a number of dry type scrubbing system designs. However, all consist of two main sections or devices: a device to introduce the acid gas
sorbent
material into the gas stream and a particulate matter control device to remove reaction products, excess sorbent material as well as any particulate matter already in the flue gas
.
Dry scrubbing systems can be categorized as dry sorbent injectors (DSIs) or as spray dryer absorbers (SDAs). Spray dryer absorbers are also called semi-dry scrubbers or spray dryers.
Dry scrubbing systems are often used for the removal of odorous and corrosive gases from wastewater treatment plant
operations. The medium used is typically an activated alumina
compound impregnated with materials to handle specific gases such as hydrogen sulfide
. Media used can be mixed together to offer a wide range of removal for other odorous compounds such as methyl mercaptans, aldehyde
s, volatile organic compound
s, dimethyl sulfide
, and dimethyl disulfide
.
Dry sorbent injection involves the addition of an alkaline material (usually hydrated lime or soda ash) into the gas stream to react with the acid gas
es. The sorbent can be injected directly into several different locations: the combustion process, the flue gas
duct (ahead of the particulate control device), or an open reaction chamber (if one exists). The acid gases react with the alkaline sorbent
s to form solid salt
s which are removed in the particulate control device. These simple systems can achieve only limited acid gas (SO2 and HCl) removal efficiencies. Higher collection efficiencies can be achieved by increasing the flue gas humidity
(i.e., cooling using water spray). These devices have been used on medical waste
incinerators and a few municipal waste combustors.
In spray dryer absorbers, the flue gas
es are introduced into an absorbing tower (dryer) where the gases are contacted with a finely atomized alkaline slurry
. Acid gases are absorbed by the slurry mixture and react to form solid salt
s which are removed by the particulate control device. The heat of the flue gas is used to evaporate all the water droplets, leaving a non-saturated flue gas to exit the absorber tower. Spray dryers are capable of achieving high (80+%) acid gas removal efficiencies. These devices have been used on industrial and utility boiler
s and municipal waste incinerators.
is a highly toxic element commonly found in coal
and municipal waste. Wet scrubber
s are only effective for removal of soluble mercury species, such as oxidized mercury, Hg2+. Mercury vapor in its elemental form, Hg0, is insoluble in the scrubber slurry and not removed. Therefore, additional process of Hg0 conversion is required to complete mercury capture. Usually addition of the halogens to the flue gas are used for this purpose. The type of coal burned as well as the presence of a selective catalytic reduction
unit both affect the ratio of elemental to oxidized mercury in the flue gas and thus the degree to which the mercury is removed.
. In this mode, termed a condensing scrubber, water from the scrubber drain is circulated through a cooler to the nozzles at the top of the scrubber. The hot gas enters the scrubber at the bottom. If the gas temperature is above the water dew point
, it is initially cooled by evaporation
of water drops. Further cooling cause water vapor
s to condense
, adding to the amount of circulating water.
The condensation of water release significant amounts of low temperature heat (more than 2 gigajoules (555.6 kW·h) per ton of water), that can be recovered by the cooler for e.g. district heating
purposes.
Excess condensed water must continuously be removed from the circulating water.
The gas leaves the scrubber at its dew point
, so even though significant amounts of water may have been removed from the cooled gas, it is likely to leave a visible stack plume of water vapor.
For example, mercury removal results in a waste product that either needs further processing to extract the raw mercury, or must be buried in a special hazardous wastes landfill
that prevents the mercury from seeping out into the environment.
As an example of reuse, limestone-based scrubbers in coal fired power plants can produce a synthetic gypsum
of sufficient quality that can be used to manufacture drywall
and other industrial products.
was just a few infected scrubbers. The outbreak caused 10 deaths and more than 50 cases of infection.
Air pollution
Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
control devices that can be used to remove some particulates and/or gases from industrial exhaust streams. Traditionally, the term "scrubber" has referred to pollution control devices that use liquid to wash unwanted pollutants from a gas stream. Recently, the term is also used to describe systems that inject a dry reagent or slurry
Slurry
A slurry is, in general, a thick suspension of solids in a liquid.-Examples of slurries:Examples of slurries include:* Lahars* A mixture of water and cement to form concrete* A mixture of water, gelling agent, and oxidizers used as an explosive...
into a dirty exhaust stream to "wash out" acid gas
Acid gas
Acid gas is natural gas or any other gas mixture which contains significant amounts of hydrogen sulfide , carbon dioxide , or similar contaminants. The terms acid gas and sour gas are often incorrectly treated as synonyms...
es. Scrubbers are one of the primary devices that control gaseous emissions, especially acid gases. Scrubbers can also be used for heat recovery from hot gases by flue gas condensation
Flue gas condensation
Flue gas condensation is a process, where flue gas is cooled below its water dew point and the heat released by the resulting condensation of water is recovered as low temperature heat....
.
There are several methods to remove toxic or corrosive compounds from exhaust gas and neutralize it.
Combustion
CombustionCombustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
is sometimes the cause for harmful exhaust gas, but, in many cases, combustion may also be used for exhaust gas cleaning if the temperature is high enough and enough oxygen is available.
Wet scrubbing
The exhaust gases of combustion may contain substances considered harmful to the environment, and the scrubber may remove or neutralize those substances.A wet scrubber
Wet scrubber
The term wet scrubber describes a variety of devices that remove pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by...
is used to clean air, flue gas
Flue gas
Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced at power plants...
or other gas
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
es of various pollutant
Pollutant
A pollutant is a waste material that pollutes air, water or soil, and is the cause of pollution.Three factors determine the severity of a pollutant: its chemical nature, its concentration and its persistence. Some pollutants are biodegradable and therefore will not persist in the environment in the...
s and dust
Dust
Dust consists of particles in the atmosphere that arise from various sources such as soil dust lifted up by wind , volcanic eruptions, and pollution...
particles. Wet scrubbing works via the contact of target compounds or particulate matter with the scrubbing solution. Solutions may simply be water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
(for dust) or solutions of reagents that specifically target certain compounds.
Process exhaust gas can also contain water soluble toxic and/or corrosive gases like hydrogen chloride
Hydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
HCl or ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
NH3. These can be removed very well by a wet scrubber.
Removal efficiency of pollutants is improved by increasing residence time in the scrubber or by the increase of surface area of the scrubber solution by the use of a spray nozzle
Spray nozzle
A spray nozzle is a precision device that facilitates dispersion of liquid into a spray. Nozzles are used for three purposes: to distribute a liquid over an area, to increase liquid surface area, and create impact force on a solid surface...
, packed towers
Packed bed
In chemical processing, a packed bed is a hollow tube, pipe, or other vessel that is filled with a packing material. The packing can be randomly filled with small objects like Raschig rings or else it can be a specifically designed structured packing...
or an aspirator
Aspirator
An aspirator, also called an eductor-jet pump or filter pump, is a device that produces vacuum by means of the Venturi effect. In an aspirator, fluid flows through a tube which then narrows. When the tube narrows, the fluid's speed increases, and because of the Venturi effect, its pressure...
. Wet scrubber
Wet scrubber
The term wet scrubber describes a variety of devices that remove pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by...
s may increase the proportion of water in the gas, resulting in a visible stack plume, if the gas is sent to a stack.
Dry scrubbing
A dry or semi-dry scrubbing system, unlike the wet scrubberWet scrubber
The term wet scrubber describes a variety of devices that remove pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by...
, does not saturate the flue gas stream that is being treated with moisture. In some cases no moisture is added; while in other only the amount of moisture that can be evaporated in the flue gas without condensing is added. Therefore, dry scrubbers do generally not have a stack steam plume or wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
handling/disposal requirements. Dry scrubbing systems are used to remove acid gas
Acid gas
Acid gas is natural gas or any other gas mixture which contains significant amounts of hydrogen sulfide , carbon dioxide , or similar contaminants. The terms acid gas and sour gas are often incorrectly treated as synonyms...
es (such as SO2
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
and HCl
Hydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
) primarily from combustion
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
sources.
There are a number of dry type scrubbing system designs. However, all consist of two main sections or devices: a device to introduce the acid gas
Acid gas
Acid gas is natural gas or any other gas mixture which contains significant amounts of hydrogen sulfide , carbon dioxide , or similar contaminants. The terms acid gas and sour gas are often incorrectly treated as synonyms...
sorbent
Sorbent
A sorbent is a material used to absorb liquids or gases. Examples include:*A material similar to molecular sieve material. It has a large internal surface area and good thermal conductivity. It is typically supplied in pellets of 1 mm to 2 mm diameter and roughly 5 mm length or as...
material into the gas stream and a particulate matter control device to remove reaction products, excess sorbent material as well as any particulate matter already in the flue gas
Flue gas
Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced at power plants...
.
Dry scrubbing systems can be categorized as dry sorbent injectors (DSIs) or as spray dryer absorbers (SDAs). Spray dryer absorbers are also called semi-dry scrubbers or spray dryers.
Dry scrubbing systems are often used for the removal of odorous and corrosive gases from wastewater treatment plant
Industrial wastewater treatment
Industrial wastewater treatment covers the mechanisms and processes used to treat waters that have been contaminated in some way by anthropogenic industrial or commercial activities prior to its release into the environment or its re-use....
operations. The medium used is typically an activated alumina
Activated alumina
Activated alumina is manufactured from aluminium hydroxide by dehydroxylating it in a way that produces a highly porous material; this material can have a surface area significantly over 200 square metres/g. The compound is used as a desiccant and as a filter of fluoride, arsenic and selenium in...
compound impregnated with materials to handle specific gases such as hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
. Media used can be mixed together to offer a wide range of removal for other odorous compounds such as methyl mercaptans, aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....
s, volatile organic compound
Volatile organic compound
Volatile organic compounds are organic chemicals that have a high vapor pressure at ordinary, room-temperature conditions. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and...
s, dimethyl sulfide
Dimethyl sulfide
Dimethyl sulfide or methylthiomethane is an organosulfur compound with the formula 2S. Dimethyl sulfide is a water-insoluble flammable liquid that boils at and has a characteristic disagreeable odor. It is a component of the smell produced from cooking of certain vegetables, notably maize,...
, and dimethyl disulfide
Dimethyl disulfide
Dimethyl disulfide is an organic chemical compound with the molecular formula CH3SSCH3 which is the simplest disulfide. It is a flammable liquid with an unpleasant odor.DMDS can be produced by the reaction of methanethiol with sulfur:-Uses:...
.
Dry sorbent injection involves the addition of an alkaline material (usually hydrated lime or soda ash) into the gas stream to react with the acid gas
Acid gas
Acid gas is natural gas or any other gas mixture which contains significant amounts of hydrogen sulfide , carbon dioxide , or similar contaminants. The terms acid gas and sour gas are often incorrectly treated as synonyms...
es. The sorbent can be injected directly into several different locations: the combustion process, the flue gas
Flue gas
Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced at power plants...
duct (ahead of the particulate control device), or an open reaction chamber (if one exists). The acid gases react with the alkaline sorbent
Sorbent
A sorbent is a material used to absorb liquids or gases. Examples include:*A material similar to molecular sieve material. It has a large internal surface area and good thermal conductivity. It is typically supplied in pellets of 1 mm to 2 mm diameter and roughly 5 mm length or as...
s to form solid salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
s which are removed in the particulate control device. These simple systems can achieve only limited acid gas (SO2 and HCl) removal efficiencies. Higher collection efficiencies can be achieved by increasing the flue gas humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
(i.e., cooling using water spray). These devices have been used on medical waste
Medical waste
Medical waste, also known as clinical waste, normally refers to waste products that cannot be considered general waste, produced from healthcare premises, such as hospitals, clinics, doctors offices, veterinary hospitals and labs.-Europe:...
incinerators and a few municipal waste combustors.
In spray dryer absorbers, the flue gas
Flue gas
Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced at power plants...
es are introduced into an absorbing tower (dryer) where the gases are contacted with a finely atomized alkaline slurry
Slurry
A slurry is, in general, a thick suspension of solids in a liquid.-Examples of slurries:Examples of slurries include:* Lahars* A mixture of water and cement to form concrete* A mixture of water, gelling agent, and oxidizers used as an explosive...
. Acid gases are absorbed by the slurry mixture and react to form solid salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
s which are removed by the particulate control device. The heat of the flue gas is used to evaporate all the water droplets, leaving a non-saturated flue gas to exit the absorber tower. Spray dryers are capable of achieving high (80+%) acid gas removal efficiencies. These devices have been used on industrial and utility boiler
Boiler
A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.-Materials:...
s and municipal waste incinerators.
Absorber
Many chemicals can be removed from exhaust gas also by using absorber material. The flue gas is passed through a cartridge, filled with one or several absorber materials, adapted to the chemical properties of the components that should be removed from the exhaust gas. This type of scrubber is sometimes also called dry scrubber. The absorber material has to be replaced after its surface is saturated.Mercury removal
MercuryMercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
is a highly toxic element commonly found in coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
and municipal waste. Wet scrubber
Wet scrubber
The term wet scrubber describes a variety of devices that remove pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by...
s are only effective for removal of soluble mercury species, such as oxidized mercury, Hg2+. Mercury vapor in its elemental form, Hg0, is insoluble in the scrubber slurry and not removed. Therefore, additional process of Hg0 conversion is required to complete mercury capture. Usually addition of the halogens to the flue gas are used for this purpose. The type of coal burned as well as the presence of a selective catalytic reduction
Selective catalytic reduction
Selective catalytic reduction is a means of converting nitrogen oxides, also referred to as with the aid of a catalyst into diatomic nitrogen , , and water, . A gaseous reductant, typically anhydrous ammonia, aqueous ammonia or urea, is added to a stream of flue or exhaust gas and is absorbed...
unit both affect the ratio of elemental to oxidized mercury in the flue gas and thus the degree to which the mercury is removed.
Heat recovery
Wet scrubbers can be used for heat recovery from hot gases by flue gas condensationFlue gas condensation
Flue gas condensation is a process, where flue gas is cooled below its water dew point and the heat released by the resulting condensation of water is recovered as low temperature heat....
. In this mode, termed a condensing scrubber, water from the scrubber drain is circulated through a cooler to the nozzles at the top of the scrubber. The hot gas enters the scrubber at the bottom. If the gas temperature is above the water dew point
Dew point
The dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into liquid water. The condensed water is called dew when it forms on a solid surface. The dew point is a saturation temperature.The dew point is...
, it is initially cooled by evaporation
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
of water drops. Further cooling cause water vapor
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
s to condense
Condensation
Condensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
, adding to the amount of circulating water.
The condensation of water release significant amounts of low temperature heat (more than 2 gigajoules (555.6 kW·h) per ton of water), that can be recovered by the cooler for e.g. district heating
District heating
District heating is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating...
purposes.
Excess condensed water must continuously be removed from the circulating water.
The gas leaves the scrubber at its dew point
Dew point
The dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into liquid water. The condensed water is called dew when it forms on a solid surface. The dew point is a saturation temperature.The dew point is...
, so even though significant amounts of water may have been removed from the cooled gas, it is likely to leave a visible stack plume of water vapor.
Scrubber waste products
One side effect of scrubbing is that the process only moves the unwanted substance from the exhaust gases into a liquid solution, solid paste or powder form. This must be disposed of safely, if it can not be reused.For example, mercury removal results in a waste product that either needs further processing to extract the raw mercury, or must be buried in a special hazardous wastes landfill
Landfill
A landfill site , is a site for the disposal of waste materials by burial and is the oldest form of waste treatment...
that prevents the mercury from seeping out into the environment.
As an example of reuse, limestone-based scrubbers in coal fired power plants can produce a synthetic gypsum
Gypsum
Gypsum is a very soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. It is found in alabaster, a decorative stone used in Ancient Egypt. It is the second softest mineral on the Mohs Hardness Scale...
of sufficient quality that can be used to manufacture drywall
Drywall
Drywall, also known as plasterboard, wallboard or gypsum board is a panel made of gypsum plaster pressed between two thick sheets of paper...
and other industrial products.
Bacteria spread
Poorly maintained scrubbers have the potential to spread disease-causing bacteria. The problem is a result of inadequate cleaning. For example, the cause of a 2005 outbreak of Legionnaires' disease in NorwayNorway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
was just a few infected scrubbers. The outbreak caused 10 deaths and more than 50 cases of infection.
See also
- Wet scrubberWet scrubberThe term wet scrubber describes a variety of devices that remove pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by...
- Baffle spray scrubberBaffle spray scrubberBaffle spray scrubbers are a technology for air pollution control. They are very similar to spray towers in design and operation. However, in addition to using the energy provided by the spray nozzles, baffles are added to allow the gas stream to atomize some liquid as it passes over them.A simple...
- Ejector venturi scrubberEjector venturi scrubberThis type of technology is a part of the group of air pollution controls collectively referred to as wet scrubbers.An ejector or venturi scrubber is an industrial pollution control device, usually installed on the exhaust flue gas stacks of large furnaces, but may also be used on any number of...
- Liquid-to-gas ratioLiquid-to-gas ratioAn important parameter in wet scrubbing systems is the rate of liquid flow. It is common in wet scrubber terminology to express the liquid flow as a function of the gas flow rate that is being treated...
- Mechanically aided scrubberMechanically aided scrubberMechanically aided scrubbers are a form of pollution control technology. This type of technology is a part of the group of air pollution controls collectively referred to as wet scrubbers....
- Spray towerSpray towerSpray towers or spray chambers are a form of pollution control technology. They consist of empty cylindrical vessels made of steel or plastic and nozzles that spray liquid into the vessels. The inlet gas stream usually enters the bottom of the tower and moves upward, while liquid is sprayed...
- Spray nozzleSpray nozzleA spray nozzle is a precision device that facilitates dispersion of liquid into a spray. Nozzles are used for three purposes: to distribute a liquid over an area, to increase liquid surface area, and create impact force on a solid surface...
- Stripping (chemistry)Stripping (chemistry)Stripping is a physical separation process where one or more components are removed from a liquid stream by a vapor stream. In industrial applications the liquid and vapor streams can have co-current or countercurrent flows. Stripping is usually carried out in either a packed or trayed column.-...
- Venturi scrubberVenturi scrubberA venturi scrubber is designed to effectively use the energy from the inlet gas stream to atomize the liquid being used to scrub the gas stream...
- Air Turbo-Impactor
- Baffle spray scrubber
- Flue gas desulfurizationFlue gas desulfurizationSulfur dioxide is one of the elements forming acid rain. Tall flue-gas stacks disperse emissions by diluting the pollutants in ambient air and transporting them to other regions....
- Flue gas condensationFlue gas condensationFlue gas condensation is a process, where flue gas is cooled below its water dew point and the heat released by the resulting condensation of water is recovered as low temperature heat....
- Oil desulfurization
- Electrostatic precipitatorElectrostatic precipitatorAn electrostatic precipitator , or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas using the force of an induced electrostatic charge...
- BS4994BS4994BS4994 is the "specification for the design and construction of vessels and storage tanks in reinforced plastics"...
Chemical Process Plant Equipments in FRP