CA1056578A - Method and apparatus for removing pollutants from a gaseous mixture - Google Patents
Method and apparatus for removing pollutants from a gaseous mixtureInfo
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- CA1056578A CA1056578A CA238,812A CA238812A CA1056578A CA 1056578 A CA1056578 A CA 1056578A CA 238812 A CA238812 A CA 238812A CA 1056578 A CA1056578 A CA 1056578A
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Abstract
METHOD AND APPARATUS FOR REMOVING
POLLUTANTS FROM A GASEOUS MIXTURE
ABSTRACT
Method and apparatus for treating of waste gases, such as hot-flue gases, to remove therefrom pollutants in the form of solids, such as fly-ash and the like; and also for the removal of chemical substances present in a gaseous form, such as the oxides of sulphur. The solid waste materials, such as fly-ash, are removed from the flue gases by mechanical separation, while the gaseous pollutants, such as sulphur dioxide and/or sulphur trioxide are removed by a scrubbing action with another chemical substance carried in a solu-tion and dispersed by spray action. The polluted gas is preferably first passed through some form of mechanical separator for removal of solids, and is then passed through a sinuous channel, preferably containing a U-shaped chamber, wherein as the gas descends through one leg of said chamber, it is sprayed with the reactive solution to produce a precipitate that descends to the base of the chamber by gravity, and as the gas ascends through the other leg of the chamber, it is again treated with said solution to react and remove as much of the gaseous pollutant as is possible.
By reason of the high temperature of the flue gases, and the control of the flow of the fluids, the precipitate is in a dry and powdery condition, wherein it can be collected either in the treatment chamber, or by subsequent mechanical separation. The solids either in the form of fly-ash, or the reaction product of the chemical treatment, and particularly the latter, may have commercial value for other purposes.
POLLUTANTS FROM A GASEOUS MIXTURE
ABSTRACT
Method and apparatus for treating of waste gases, such as hot-flue gases, to remove therefrom pollutants in the form of solids, such as fly-ash and the like; and also for the removal of chemical substances present in a gaseous form, such as the oxides of sulphur. The solid waste materials, such as fly-ash, are removed from the flue gases by mechanical separation, while the gaseous pollutants, such as sulphur dioxide and/or sulphur trioxide are removed by a scrubbing action with another chemical substance carried in a solu-tion and dispersed by spray action. The polluted gas is preferably first passed through some form of mechanical separator for removal of solids, and is then passed through a sinuous channel, preferably containing a U-shaped chamber, wherein as the gas descends through one leg of said chamber, it is sprayed with the reactive solution to produce a precipitate that descends to the base of the chamber by gravity, and as the gas ascends through the other leg of the chamber, it is again treated with said solution to react and remove as much of the gaseous pollutant as is possible.
By reason of the high temperature of the flue gases, and the control of the flow of the fluids, the precipitate is in a dry and powdery condition, wherein it can be collected either in the treatment chamber, or by subsequent mechanical separation. The solids either in the form of fly-ash, or the reaction product of the chemical treatment, and particularly the latter, may have commercial value for other purposes.
Description
1~56578 SPECI~ICA~IO~
~ .
This invention relates to improvements in the treatme~t of waste gases, such as a hot gaseous mixture, produced b~ combustion in a ~urnace or the like, in which pollutants may consist of active chemical substances, as well as solids and other inert gasO
- It is well known that fossil fuels, such as coal and petroleum products contain, in addition to the hydrocarbons, sulphur cr ma-terials combined with sulphur, and the combustion process combines these m~terials into chemicall~ active ~0 substanc~s in a gaseous form that may contai~ S02 and/or S03, which are highly undesirable, since these gases are injurious in themselves and in the presence of moisture may ~orm sulphurous or ~.
sulphuric acidsO
In the present invention, in addition to providîng means for removing solids from the flue gases, provision is also made to remove the sulphurous products by reacting the same with another substance such as ~a2CO~, and thereby formulate a dr~ crystalline compound that would have commercial value.
,~ ~
,~ ~, .
~5~57E~
In more particularity 9 the chemical reaction causing such precipitation and the removal of pollutants from the dust-gas mix-ture may, in the preferred embodiment, involve a novel apparatus and method of desulphurization of hot ~lue gas.
An object of the invention i9 to provide an improved method and means for treat~
ing a p~luted gaseous mixture, such as hot flue gas by mechanically removing particulate solid matter therefrom, and further, by removing other pollutants in the hot flue gas by chemical reaction, causing precipitation thereof in a novel manner.
A further object of the invention is in the provision of a novel method and apparatus for removing a pollutant from a hot gaseous mixture b~ passing the mixture through a channel having therein at least two non-horizontal portions wherein the mixture is subaect to reaction wi~h another chemically active substance to produce precipitation of the newly formed compound i~ a step-by-step manner.
A further object of the invention is in the provision of a novel method and apparatus for removing a pollutant~ such as S02~ and/or S03 from a hot gaseous mixture wherein the flue gas is exposed to a strong but mist-like flow o~ a reagent, such as ~a2C03 in solution, which chemi call~ reacts with the pollutant to produce preci-pitation while the gas flow is in one direction, 1~56578 such as descension in a passage, during which a major portion of the sulphurous substance in the gas is precipitated, and following a substantial reversal o~ direction of flow of the flue ~as to expose the remaining S02 and/or S03 in the gas to a ~urther mist-like spray of the same reagent solution for ~urther precipitation.
The above and further objects of the invention may become apparent by re~erence to the accompa~ying drawing, showing a preferred embodi-ment thereo~, along with the accompanying descrip-tion thereo~.
~ he sole figure, comprising the drawing, shows in a flow diagram a novel method and s~stem for eliminating pollutants in flue gas emitted from a furnace.
In said figure, a pollutant removing system in its entiret~, indicated by general numeral 10, receives hot flue gas from a furnace 129 through a conduit 14~ The flue gas, as it leaves furnace 12 has a temperature of about 3Q0-350F., and includes various pollutants which render the flue gas below an allowable ecological standard for delivery to the atmosphere~ Consequently, the flue gas is delivered to a ~ly-ash collector 16, wherein a major portion of the entrained solids are removed and from which the gas flows through a suitable conduit 18 to a novel separati~g tower 20.
~he separating tower 20 is of generally sinuous, or U-shaped con~iguration. Its inlet end 22 extends from conduit 18 to a non-hori~ontal ~L~S6578 or descending portion or passage 24 that aoin3 one side of a hopper 26. ~he hopper 26, in turn, is connected to a non-horizontal or ascending portion or passage 28 of the tower that has a discharge opening 30 that joi~s a conduit 32 containing a damper 34~ Conduit 32 extends to a ~iltering device 36, which device is connected b~
a conduit 38 to a further flltering device 40.
~rom the filtering device 40, a conduit 42 ex~ends to a blower 44 which~ in tur~, connects to a chi~ney or other gas disposal device 46.
Hopper 26 forms a common connecting passage between portions 24 and 28 of the tower 20, and its lower end is connected b~ a conduit 48 to a discharge trough 50 o~ a product handling system~
Trough 50 is also connected b~ discharge conduits 52 and 54 from the filtering devices 36 and 40, and extends to a common collecting container 56~
The fl~-ash collector 16 has a discharge passage 58 which extends to a trough 60, which, in turn, connecte to a disposal container or fl~-ash storage hopper 62.
~ o provide a solution to chemically react with sulphurous substances in the gas~ a storage bin 64 adapted to receive a chemically active material, such as Na2C03 9 or o-ther basic material, is provided with a valve 66 that forms a controlled passage to a conduit 68 which, in turn~
extends to a hopper 70. Hopper 70 is prov~ded with a valve 72 connecting to a conduit 74 whlch extends to a mixing tank 76. A water supply line 78, ~56578 containing a valve 80 also extends to the mixing tank 76. The tank 76 is provided with an agita-tor 82~ driven by a motor means 840 .A conduit 86, containing a valve 88 extends from the mixing tank 76 to a feed tank 90, which contains a screen or o-ther filtering device 92. A pump 94 has its inlet connected by a conduit 96 to the feed tank 90, and said pump has its discharge end conne~ted to a pipe 98 extending to the mixing tank 76, and contains a Yalve lOOo A pump 102 has its inlet end connected to a conduit 104 which extends from a lower e~d of the feed tank 90. ~aid pump has its discharge end connected to a conduit 106 which contains a valve 108 and extends to a spray-head 110 located in the upper end of portion 24 of tower 20.
Another spra~-head 112 also extends from conduit 106 within the tower portion 24 beneath the spra~-head 110, bu-t above the hopper portion 26. A con-duit 114 containing a valve 116 extends from con-duit 106 to a spray-head 118 that is disposed within the interior of portion 28 of the tower 20.
Reference numeral 120 designates a sens-ing device which is reactive to a condition within portion 24 of the tower 20, such as the proportion of sulphurous material present in the gases in that portion of the tower downstream of spra~-heads 110, 112, in the direction of gas flow.
Reference character 122 indicates a similar sens-~0 ing device that is reactive to the condition of the gases in portion 28 of tower 20 downstream of 65~l~
spray-head 118. ~he sensor 120 is operatively connected to valve 108; while sensor 122 is operatively connected to the valve 116, each of said sensors being adapted to con-trol the posi-tioning of the respective valves 108 and 116 so as to control or modulate the quantit~ of material such as the reactive solution through the respective valves. A sensor 124 for se~sing humidity or other similar conditions wi-thin the lower portion of hopper 26 is operati~ely con-nected to a differential control device 126 which also, like se~sor 120, has the capacity of con-trolling valve 108.
~he operation of the invention and the system disclosed in the drawing will now be dis-cussed. With combustion of fossil fuel occurring in the furnace 12, hot waste flue gases emitte~
from the furnace at about 300-350~. are trans-mitted through conduit 14 to the fly-ash collector 16 where a major portion of the solids present in the gases will be removed. ~he gas, with other pollutants therein, then passes through conduit 18 to the inlet end of tower 20, where it flows downwardly through the leg 24. A reactive solu-tion composed of about 5/~12% of ~a2C03 in water is formed in the mixing tank 76 and dispensed to the feed tank 90, The solution is circulated be-tween the mixing tank and the feed tank to main tain a relatively uniform solution~ The solution is then delivered by pump 102 to conduit 106 and through the valve 108 -therein to the spray-heads S6S'7l3 1 110, 112, where it is sprayed in a mist-like form into the gases descending through portion 24 of the tower 20, preferably in opposition to the direction of flow of the gas. The following chemical reaction occurs:
S2 + Na2C03 -~ > Na2S3 + C2 I + O -----> Na2S04 and SO3 ~ Na2CO3 ------> Na2S4 -~ C2 In a typical reaction with the products of combustion 1~ of a fossil fuel the above specified compounds produce approximately 71%-76~ Na2SO3 (sodium sulphite) and 10%-20 Na2SO~ (sodium sulphate), depending upon the combustion conditions and th~ fuel composition.
Although sodium carbonate in the percentage range noted in the prior paragraphs is the preferred embodiment, that is the range of 5~ to 12%, the basic compound obtained from thermal decomposition of trona (urao) could be used to react with the SO2 and SO3 to form the by-product. In factl any suitable strong basic compound which would react with SO2 and SO3 to form a particular by-product would be suitable.
The gases flowing downwardly from the le~ or portion 24 into hopper 26 will normally not be completely free of the sulphurous compounds, but these gases then flow upwardly through the leg or portion 28, where they are again sub~ected to a spray treatment with the Na2CO3 solution, which in this instance is sprayed downwardly against the flow path of the gas.
The control of the flow of solution to spray-heads 110, 112 and 118 is by the valves 108 and 116 responding to the sensors 120 and 122.
The total flow of the Na2CO3 solution is controlled so that a maximum amount of SO2 and/or SO3 are removed from the flue gas, but in a condition such that the precipitate is - relatively dry~
~ 8 --1~565~
The sensor-120 acts to allow flow of solution through valve 108 -to remove a maJor portion of the sulphurous substances from the gas, but in the interes-t of economical use of the ~a2C0 solution there should be a small amount of sulphurous substance remaining in the flue gas entering hopper 26 and passing upwardly through the portion 28. However, the sensin6 device 122, which reacts ~o the g~ses a~ter treatmen-t b~ the spray-head 118 should substantially eliminate free ~2 and/or ~ree S03 from the flue gases. It is highly desirable that the precipitate be in a dry dust-like condition, and despite treatment of the gases with a water-containing solution1 this is possible because of the high temperature of the gases. Nonetheless, the control device 124 is reactive to the humidity conditions in the hopper 25 and its function is to coordinate the total flow of liquid through the valve 108.
As a further control of the react~n be-tween the ~a2C03 and the sulphurous oxides within the flue gases in tower 20, damper 34 is utilized to control the flow of gases from tower 20 to and through the filtering devices 36 and 40 to the chimney 46. Damper 34 controls flow rate of the gas and thus the time that gases are in tower 20, thereby yielding more efficient and complete cleaning of the S02,S03 from the gas. Therefore, proper control of the chemical reactions and of the mechanical filtration is su~aect to control on the one nand by the sensing devices 120, 122 and 124, and also by the flow control device 34D
l~5~iS78 A~ter leaving leg or portion 28 of tower 20, the gases flow through filtering devices 36 and 40, which are composed of cyclone separators, or other forms of mechanical separa-tors that will remove any residual portion o~
the precipitate, or other solids present in the waste gases before they are discharged b~ blower 44 through the chimney ~6~
m e solid materials constituting the precipitates and other solid materials, i~ any, àre gathered in the product storage hopper 56.
As noted above, a major portion of this material may consist o~ ~a2~0,~ (sodium sulphite), which will find commercial value in other industries~
such as paper making or the like.
~ .
This invention relates to improvements in the treatme~t of waste gases, such as a hot gaseous mixture, produced b~ combustion in a ~urnace or the like, in which pollutants may consist of active chemical substances, as well as solids and other inert gasO
- It is well known that fossil fuels, such as coal and petroleum products contain, in addition to the hydrocarbons, sulphur cr ma-terials combined with sulphur, and the combustion process combines these m~terials into chemicall~ active ~0 substanc~s in a gaseous form that may contai~ S02 and/or S03, which are highly undesirable, since these gases are injurious in themselves and in the presence of moisture may ~orm sulphurous or ~.
sulphuric acidsO
In the present invention, in addition to providîng means for removing solids from the flue gases, provision is also made to remove the sulphurous products by reacting the same with another substance such as ~a2CO~, and thereby formulate a dr~ crystalline compound that would have commercial value.
,~ ~
,~ ~, .
~5~57E~
In more particularity 9 the chemical reaction causing such precipitation and the removal of pollutants from the dust-gas mix-ture may, in the preferred embodiment, involve a novel apparatus and method of desulphurization of hot ~lue gas.
An object of the invention i9 to provide an improved method and means for treat~
ing a p~luted gaseous mixture, such as hot flue gas by mechanically removing particulate solid matter therefrom, and further, by removing other pollutants in the hot flue gas by chemical reaction, causing precipitation thereof in a novel manner.
A further object of the invention is in the provision of a novel method and apparatus for removing a pollutant from a hot gaseous mixture b~ passing the mixture through a channel having therein at least two non-horizontal portions wherein the mixture is subaect to reaction wi~h another chemically active substance to produce precipitation of the newly formed compound i~ a step-by-step manner.
A further object of the invention is in the provision of a novel method and apparatus for removing a pollutant~ such as S02~ and/or S03 from a hot gaseous mixture wherein the flue gas is exposed to a strong but mist-like flow o~ a reagent, such as ~a2C03 in solution, which chemi call~ reacts with the pollutant to produce preci-pitation while the gas flow is in one direction, 1~56578 such as descension in a passage, during which a major portion of the sulphurous substance in the gas is precipitated, and following a substantial reversal o~ direction of flow of the flue ~as to expose the remaining S02 and/or S03 in the gas to a ~urther mist-like spray of the same reagent solution for ~urther precipitation.
The above and further objects of the invention may become apparent by re~erence to the accompa~ying drawing, showing a preferred embodi-ment thereo~, along with the accompanying descrip-tion thereo~.
~ he sole figure, comprising the drawing, shows in a flow diagram a novel method and s~stem for eliminating pollutants in flue gas emitted from a furnace.
In said figure, a pollutant removing system in its entiret~, indicated by general numeral 10, receives hot flue gas from a furnace 129 through a conduit 14~ The flue gas, as it leaves furnace 12 has a temperature of about 3Q0-350F., and includes various pollutants which render the flue gas below an allowable ecological standard for delivery to the atmosphere~ Consequently, the flue gas is delivered to a ~ly-ash collector 16, wherein a major portion of the entrained solids are removed and from which the gas flows through a suitable conduit 18 to a novel separati~g tower 20.
~he separating tower 20 is of generally sinuous, or U-shaped con~iguration. Its inlet end 22 extends from conduit 18 to a non-hori~ontal ~L~S6578 or descending portion or passage 24 that aoin3 one side of a hopper 26. ~he hopper 26, in turn, is connected to a non-horizontal or ascending portion or passage 28 of the tower that has a discharge opening 30 that joi~s a conduit 32 containing a damper 34~ Conduit 32 extends to a ~iltering device 36, which device is connected b~
a conduit 38 to a further flltering device 40.
~rom the filtering device 40, a conduit 42 ex~ends to a blower 44 which~ in tur~, connects to a chi~ney or other gas disposal device 46.
Hopper 26 forms a common connecting passage between portions 24 and 28 of the tower 20, and its lower end is connected b~ a conduit 48 to a discharge trough 50 o~ a product handling system~
Trough 50 is also connected b~ discharge conduits 52 and 54 from the filtering devices 36 and 40, and extends to a common collecting container 56~
The fl~-ash collector 16 has a discharge passage 58 which extends to a trough 60, which, in turn, connecte to a disposal container or fl~-ash storage hopper 62.
~ o provide a solution to chemically react with sulphurous substances in the gas~ a storage bin 64 adapted to receive a chemically active material, such as Na2C03 9 or o-ther basic material, is provided with a valve 66 that forms a controlled passage to a conduit 68 which, in turn~
extends to a hopper 70. Hopper 70 is prov~ded with a valve 72 connecting to a conduit 74 whlch extends to a mixing tank 76. A water supply line 78, ~56578 containing a valve 80 also extends to the mixing tank 76. The tank 76 is provided with an agita-tor 82~ driven by a motor means 840 .A conduit 86, containing a valve 88 extends from the mixing tank 76 to a feed tank 90, which contains a screen or o-ther filtering device 92. A pump 94 has its inlet connected by a conduit 96 to the feed tank 90, and said pump has its discharge end conne~ted to a pipe 98 extending to the mixing tank 76, and contains a Yalve lOOo A pump 102 has its inlet end connected to a conduit 104 which extends from a lower e~d of the feed tank 90. ~aid pump has its discharge end connected to a conduit 106 which contains a valve 108 and extends to a spray-head 110 located in the upper end of portion 24 of tower 20.
Another spra~-head 112 also extends from conduit 106 within the tower portion 24 beneath the spra~-head 110, bu-t above the hopper portion 26. A con-duit 114 containing a valve 116 extends from con-duit 106 to a spray-head 118 that is disposed within the interior of portion 28 of the tower 20.
Reference numeral 120 designates a sens-ing device which is reactive to a condition within portion 24 of the tower 20, such as the proportion of sulphurous material present in the gases in that portion of the tower downstream of spra~-heads 110, 112, in the direction of gas flow.
Reference character 122 indicates a similar sens-~0 ing device that is reactive to the condition of the gases in portion 28 of tower 20 downstream of 65~l~
spray-head 118. ~he sensor 120 is operatively connected to valve 108; while sensor 122 is operatively connected to the valve 116, each of said sensors being adapted to con-trol the posi-tioning of the respective valves 108 and 116 so as to control or modulate the quantit~ of material such as the reactive solution through the respective valves. A sensor 124 for se~sing humidity or other similar conditions wi-thin the lower portion of hopper 26 is operati~ely con-nected to a differential control device 126 which also, like se~sor 120, has the capacity of con-trolling valve 108.
~he operation of the invention and the system disclosed in the drawing will now be dis-cussed. With combustion of fossil fuel occurring in the furnace 12, hot waste flue gases emitte~
from the furnace at about 300-350~. are trans-mitted through conduit 14 to the fly-ash collector 16 where a major portion of the solids present in the gases will be removed. ~he gas, with other pollutants therein, then passes through conduit 18 to the inlet end of tower 20, where it flows downwardly through the leg 24. A reactive solu-tion composed of about 5/~12% of ~a2C03 in water is formed in the mixing tank 76 and dispensed to the feed tank 90, The solution is circulated be-tween the mixing tank and the feed tank to main tain a relatively uniform solution~ The solution is then delivered by pump 102 to conduit 106 and through the valve 108 -therein to the spray-heads S6S'7l3 1 110, 112, where it is sprayed in a mist-like form into the gases descending through portion 24 of the tower 20, preferably in opposition to the direction of flow of the gas. The following chemical reaction occurs:
S2 + Na2C03 -~ > Na2S3 + C2 I + O -----> Na2S04 and SO3 ~ Na2CO3 ------> Na2S4 -~ C2 In a typical reaction with the products of combustion 1~ of a fossil fuel the above specified compounds produce approximately 71%-76~ Na2SO3 (sodium sulphite) and 10%-20 Na2SO~ (sodium sulphate), depending upon the combustion conditions and th~ fuel composition.
Although sodium carbonate in the percentage range noted in the prior paragraphs is the preferred embodiment, that is the range of 5~ to 12%, the basic compound obtained from thermal decomposition of trona (urao) could be used to react with the SO2 and SO3 to form the by-product. In factl any suitable strong basic compound which would react with SO2 and SO3 to form a particular by-product would be suitable.
The gases flowing downwardly from the le~ or portion 24 into hopper 26 will normally not be completely free of the sulphurous compounds, but these gases then flow upwardly through the leg or portion 28, where they are again sub~ected to a spray treatment with the Na2CO3 solution, which in this instance is sprayed downwardly against the flow path of the gas.
The control of the flow of solution to spray-heads 110, 112 and 118 is by the valves 108 and 116 responding to the sensors 120 and 122.
The total flow of the Na2CO3 solution is controlled so that a maximum amount of SO2 and/or SO3 are removed from the flue gas, but in a condition such that the precipitate is - relatively dry~
~ 8 --1~565~
The sensor-120 acts to allow flow of solution through valve 108 -to remove a maJor portion of the sulphurous substances from the gas, but in the interes-t of economical use of the ~a2C0 solution there should be a small amount of sulphurous substance remaining in the flue gas entering hopper 26 and passing upwardly through the portion 28. However, the sensin6 device 122, which reacts ~o the g~ses a~ter treatmen-t b~ the spray-head 118 should substantially eliminate free ~2 and/or ~ree S03 from the flue gases. It is highly desirable that the precipitate be in a dry dust-like condition, and despite treatment of the gases with a water-containing solution1 this is possible because of the high temperature of the gases. Nonetheless, the control device 124 is reactive to the humidity conditions in the hopper 25 and its function is to coordinate the total flow of liquid through the valve 108.
As a further control of the react~n be-tween the ~a2C03 and the sulphurous oxides within the flue gases in tower 20, damper 34 is utilized to control the flow of gases from tower 20 to and through the filtering devices 36 and 40 to the chimney 46. Damper 34 controls flow rate of the gas and thus the time that gases are in tower 20, thereby yielding more efficient and complete cleaning of the S02,S03 from the gas. Therefore, proper control of the chemical reactions and of the mechanical filtration is su~aect to control on the one nand by the sensing devices 120, 122 and 124, and also by the flow control device 34D
l~5~iS78 A~ter leaving leg or portion 28 of tower 20, the gases flow through filtering devices 36 and 40, which are composed of cyclone separators, or other forms of mechanical separa-tors that will remove any residual portion o~
the precipitate, or other solids present in the waste gases before they are discharged b~ blower 44 through the chimney ~6~
m e solid materials constituting the precipitates and other solid materials, i~ any, àre gathered in the product storage hopper 56.
As noted above, a major portion of this material may consist o~ ~a2~0,~ (sodium sulphite), which will find commercial value in other industries~
such as paper making or the like.
Claims (8)
1. A method of treating a high temperature waste gaseous product containing a chemically active substance which consists of SO2 and/or SO3, comprising the steps of:
(a) passing said gaseous product at its elevated temperature through the interior of a substantially upright U-shaped channel;
(b) dispersing as a mist into the interior of said channel in at least one limited area therein within the flow path of said gaseous product, an aqueous solution containing a material which reacts with the chemically active substance in said gaseous product producing a precipitate, and concomitantly evaporat-ing the moisture of the mist by the elevated tempera-ture of said gaseous product to form a separable relatively dry reaction product;
(c) and controlling a condition relating to the dis-persion of said solution within said channel in response to a measurement of a condition of at least one portion of the contents of said channel at a point between the opposite ends of said channel.
(a) passing said gaseous product at its elevated temperature through the interior of a substantially upright U-shaped channel;
(b) dispersing as a mist into the interior of said channel in at least one limited area therein within the flow path of said gaseous product, an aqueous solution containing a material which reacts with the chemically active substance in said gaseous product producing a precipitate, and concomitantly evaporat-ing the moisture of the mist by the elevated tempera-ture of said gaseous product to form a separable relatively dry reaction product;
(c) and controlling a condition relating to the dis-persion of said solution within said channel in response to a measurement of a condition of at least one portion of the contents of said channel at a point between the opposite ends of said channel.
2. The method described in claim 1, in which the aqueous solution contains Na2CO3.
3. The method described in claim 1, in which the rate of flow of said gaseous product is controlled to effect substan-tial separation of said reaction product in a relatively dry form within said U-shaped channel.
4. The method described in claim 1, in which the disper-sion of the solution is controlled in response to the measurement of the moisture content of the gaseous product.
5. The method described in claim 1, in which the disper-sion of the solution is controlled in response to a measurement of the moisture content of the solid reaction product which is separated from the gaseous product.
6. A method of treating a high temperature waste gaseous product containing a chemically active substance which consists of SO2 and/or SO3, comprising the steps of:
(a) passing said gaseous product at its elevated temperature through the interior of a substantially upright U-shaped channel;
(b) dispersing as a mist into the interior of each of the vertically extending portions of said channel, an aqueous solution containing a material which reacts with the chemically active substance in said gaseous product producing a precipitate and concomitantly evaporating moisture of the mist by the elevated temperature of said gaseous product forming a separ-able relatively dry reaction product;
(c) controlling the rate of flow of said gaseous product through said channel to effect substantial separation of said reaction product from within the interior of said channel;
(d) and controlling dispersion of said solution with-in said channel in response to a measurement of the gaseous content of said channel downstream of the
6. A method of treating a high temperature waste gaseous product containing a chemically active substance which consists of SO2 and/or SO3, comprising the steps of:
(a) passing said gaseous product at its elevated temperature through the interior of a substantially upright U-shaped channel;
(b) dispersing as a mist into the interior of each of the vertically extending portions of said channel, an aqueous solution containing a material which reacts with the chemically active substance in said gaseous product producing a precipitate and concomitantly evaporating moisture of the mist by the elevated temperature of said gaseous product forming a separ-able relatively dry reaction product;
(c) controlling the rate of flow of said gaseous product through said channel to effect substantial separation of said reaction product from within the interior of said channel;
(d) and controlling dispersion of said solution with-in said channel in response to a measurement of the gaseous content of said channel downstream of the
Claim 6 continued....
point of dispersion in the first vertically extending portion of said channel.
point of dispersion in the first vertically extending portion of said channel.
7. A process described in claim 6, in which the disper-sion of the solution is controlled in response to a measurement of a condition of the contents of said channel downstream of the point of dispersion in the second vertically extending portion of said channel.
8. Apparatus for chemically treating a high temperature waste gaseous product containing a chemically active substance which consists of SO2 and/or SO3, comprising:
(a) a vertically positioned U-shaped chamber com-posed of alternate gas-descending and gas-ascending passageways, and forming a sinuous path;
(b) means for passing said gaseous product in sequence through both of said passageways of said chamber;
(c) means forming a supply source of a solution con-taining a chemically active substance which is reac-tive with the chemically active substance in said gaseous product;
(d) means for dispensing said solution within at least one of said passageways in such a manner as to react with the chemically active substance carried by said gaseous product;
(e) and means for controlling the flow of said solu-tion relative to the flow of said gaseous product within said chamber to react with a major portion of the chemically active substance carried by said gas-eous product and compose a relatively dry material which is precipitated from said gaseous product.
(a) a vertically positioned U-shaped chamber com-posed of alternate gas-descending and gas-ascending passageways, and forming a sinuous path;
(b) means for passing said gaseous product in sequence through both of said passageways of said chamber;
(c) means forming a supply source of a solution con-taining a chemically active substance which is reac-tive with the chemically active substance in said gaseous product;
(d) means for dispensing said solution within at least one of said passageways in such a manner as to react with the chemically active substance carried by said gaseous product;
(e) and means for controlling the flow of said solu-tion relative to the flow of said gaseous product within said chamber to react with a major portion of the chemically active substance carried by said gas-eous product and compose a relatively dry material which is precipitated from said gaseous product.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA238,812A CA1056578A (en) | 1975-10-31 | 1975-10-31 | Method and apparatus for removing pollutants from a gaseous mixture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA238,812A CA1056578A (en) | 1975-10-31 | 1975-10-31 | Method and apparatus for removing pollutants from a gaseous mixture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1056578A true CA1056578A (en) | 1979-06-19 |
Family
ID=4104420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA238,812A Expired CA1056578A (en) | 1975-10-31 | 1975-10-31 | Method and apparatus for removing pollutants from a gaseous mixture |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1056578A (en) |
-
1975
- 1975-10-31 CA CA238,812A patent/CA1056578A/en not_active Expired
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