CA1082889A - Process for the purification of gaseous effluent from industrial processes - Google Patents
Process for the purification of gaseous effluent from industrial processesInfo
- Publication number
- CA1082889A CA1082889A CA290,381A CA290381A CA1082889A CA 1082889 A CA1082889 A CA 1082889A CA 290381 A CA290381 A CA 290381A CA 1082889 A CA1082889 A CA 1082889A
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- Prior art keywords
- gaseous effluent
- liquid
- solvent
- pollutants
- gaseous
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
- Gas Separation By Absorption (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
Abstract
PROCESS FOR THE PURIFICATION OF
GASEOUS EFFLUENT FROM INDUSTRIAL PROCESSES
Abstract Described is a process for the purification of gaseous effluent of industrial processes by providing a gas containing a least a hydrocarbon solvent and/or an oxygenated solvent and passing said gas into a gas absorbing means comprised of a nonreactive liquid solvent for said gas, said liquid solvent being liquid and substantially non-volatile at ambient temperatures and pressures.
Preferably, the liquid absorbing solvent is re-claimed by separating the gaseous effluent there-from. The gaseous effluent is preferably that resulting from the application of paint.
GASEOUS EFFLUENT FROM INDUSTRIAL PROCESSES
Abstract Described is a process for the purification of gaseous effluent of industrial processes by providing a gas containing a least a hydrocarbon solvent and/or an oxygenated solvent and passing said gas into a gas absorbing means comprised of a nonreactive liquid solvent for said gas, said liquid solvent being liquid and substantially non-volatile at ambient temperatures and pressures.
Preferably, the liquid absorbing solvent is re-claimed by separating the gaseous effluent there-from. The gaseous effluent is preferably that resulting from the application of paint.
Description
Background of the Invention The present application is concerned with the area of gaseous effluent pollution control. More particularly, the invention is concerned with the gaseous effluent resulting from industrial processes, in particular, the application and drying of paint on substrates such as transportation vehicles as automobiles, trucks, and the like.
During various industrlal processes, gaseous effluent is formed. Due to the increased concern with the atmospheric environment, various processes have been suggested to control the gaseous effluent introduced into the environment.
Increased research and development has been undertaken, especially with bm:
.' ~
.' :' , - , :
~08Z88g respect to the effluent resulting from the application of liquid paints containing organic solvents to various substrates such as automobiles, trucks and the like. One such process is that described in ~.S. patent 3,932,151, which relates to paint spray booth construction and control of excess atomized paint from the air in the vicinity of a spray-painting operation.
Another proposed solution to the problem of gaseous effluent control is a technique where the gaseous effluent is absorbed onto a high surface area of carbonaceous substance, such as activated carbon, The difficulty with such a procedure is that when it came time to remove the absorbed solvent, a vacuum stripping operat-ion was employed, which therefore produced a hazardous con-dition in that the solvent was explosive at such vapor con-centrations. To overcome this problem, water was applied to the activated carbon, thereby significantly decreasing the effectiveness of the activated carbon by substantially decreasing the surface area of the activated carbon. Such an approach is highly inefficient for large voIumes of gas-eous effluent.
In designing a process for the purification of gaseous effluent one must be particularly conscious of being able to re-claim the gaseous effluent in order to make the process economically desirable from an overall point of view.
,, ~
pg/~ - 2 -108Z8~39 Summary of the Invention Broadly speaking the problems of the prior art are overcome by the present invention which provides in a process for the purification of gaseous effluent resulting from the application of liquid paint, wherein liquid paint is applied to a substrate, thereby forming a gaseous effluent containing pollutants, said gaseous effluent containing at least a hydrocarbon solvent or an ; oxygenated solvent and prior to passing effluent to the - atmosphere, removing the pollutants from the gaseous effluent, the improvement comprising; in a zone spaced from that in which the spraying of the substrate takes place, absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially water immiscible and contains only the elements carbon, hydrogen a oxygen.
Brief Description of the Drawings Fig. 1 is a schematic diagram of the process of the present invention including the use of the solvent by-products;
Fig. 2 is a schematic view of a cyclonic spray scrubber which is a liquid absorber for the gaseous effluent.
Pg/'t ~ - 3 -'' '' ,' .
1~8Z889 Descri tion of Preferred Embodiments P
Industrial processes that the present application is directed towards are any processes where s~aseous effluent is formed, which effluent is deleterious to the environment. In particular, the most preferred process is the gaseous effluent formed from the application of liquid paint.
Liquid paint is used in its broadest terms to include materials that contain organic film-form~rs dissolved in organic solvents, with or without pigments~
coating compositions regardless of how formulated, Pg/~ 3A -.. . ' ~:
, ~.
.
.
~08Z889 whether a latex or an emulsion, a slurry, a suspension and the like providing the gaseous effluent resulting therefrom contains hydrocarbon and/or oxygenated paint solvents. The gaseous effluent formed from the application of paint not only inclu~es the application of the paint itself but the volatilization of the solvent from the liquid paint during the drying of the liquid paint. By "gas" is meant to include not only a gas phase effluent but also an atomized paint overspray formed during the application of the paint to a substrate.
10The most preferred gaseous effluent is one that contains solvents for liquid paint which solvents are a mixture of substances. In particular, a hydrocarbon substance and an oxygenated substance.
~iquid paints are normally comprised of a resin ; film-former (natural or synthetic), pigments and a liquid solvent. Suitable liquid paint solvents are aliphatic alcohols from 1 to 8 carbon atoms such as methanol, ethanol, isopropanol, n-butanol, octanol, and the like; aliphatic ketones such as acetone, methylethyl ketone, methylisobutyl ketone, diisobutyl ketone cyclohexanone and the like; esters such as short chain aliphatic acids reacted with short chain aliphatic alcohols where the total number of carbon atoms of the acid and the alcohol is approximately 12, such as ethylacetate, butyl acetate, and the like; hydrocarbon solvents such as those containing up to 12 carbon atoms, as hexane, octane, cyclohexane, xylene, toluene, benzene and the like; aliphatic ethers and the like such as Cellosolve ; -4-bm:
. .
' ' ..
(trademark of Union Carbide for ethylene glycol monoethyl ether), Cellosolve* acetate, butyl Cellosolve*, and butyl Cellosolve* acetate and the like.
By "oxygenated" is meant organic solvents such as those ~or paints that contain oxygen in the molecule of the solvent either as an alcohol, a portion of an acid, an ester, or an ether.
The paints or coating compositions with which the present invention is concerned are those cont~ining film-forming organic and natural resins such as hydrocarbon resins,epoxies (such as the reaction product of bisphenol and epichlorohydrin), acrylics, polyesters, polyurethanes, alkyds, vinyls, polyamides, ureas, melamines, polyimides, silicones, polybenzimidazole and the like.
In the application of liquid paint to a substrate, the paint is atomized, such as airless, by air or electrostatically. The paint overspray from the paint spray booth is collected in a water wash by a water curtain. The paint applied to the substrate is then dried by passing it through a heated chamber wherein the solvent is volatilized.
During both the application and the drying of the paint, gaseous effluent is formed.
Prior to passing the gaseous effluent to the atmosphere the effluent is then treated according to the process of the present invention which is to sparge or bubble, ; or pass the gaseous effluent into a liquid absorbing means, such as a liquid absorber which is a solvent for the gaseous effluent.
* Trademark bm:
.
~ .
.. ' ' The liquid absorber with gaseous effluent therein may be retained in a suitable reservoir or may be subsequently collected and re-claimed as desired. The advantage of using a liquid absorbing means is that it can be readily handled, pumped, stored and reclaimed.
In its broadest aspect, the present invention is concerned with utilizing in place of the water reservoir for paint collection or the water curtain as is used currently i~
paint spray booth operations, the liquid absorbing means as is described further. By having the liquid absorbing means of the present invention employed as the overspray wash or the reservoir for collection of paint overspray, one may simplify the total pollution control of an industrial plant. In this manner there need be no variation to the organic paint systems that are currently employed, for one is concerned not with modification of the paint system itself, bu~ rather the absorption of the gaseous effluent and the most efficient, economical reclamation of the liquid absorbing means.
In the normal operation of a paint spray booth water wash, there is a curtain of water which washes the walls of a painting zone or spray booth. The water may be sprayed onto the walls or somehow collect the paint overspray. It is contemplated by this invention that the water curtain would be replaced by a curtain of liquid absorbing means described herein. It is to be appreciated that a curtain of liquid absorbing means need not be employed bu-t rather any application technique such as spraying and the like which can collect the paint overspray.
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.
-B&P 74238 The liquid absorbing means of the presentinvention is one that is non-reactive wlth the gaseous effluent. In addition, the liquid absorbing means is one that is liquid and is substantially non-volatile at ambient temperatures and pressures as well as the temperatures and pressures in which the industrial process and the reclamation of the organic solvent is operable. The liquid absorbing means consists only of carbon, hydrogen and oxygen.
Suitable liquid absorbing ~eans are those having a vapor pressure of less than 1 mm Hg pressure at 68F. (20C.), most preferably less than 0.01 mm Hg.
Examples of said liquid absorbing means are polyoxyalkylene glycol, preferably of the structure HO ~ R - O~ H where R
m contains 2 to 4 carbon atoms and m ranges from 2 to 2000 as polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol; saturated aliphatic polyols having from 2 to 12 carbon atoms as glyc~rol, ethylene glycol; dibasic esters such as the dialkyl (up to 8 carbon atoms per group~ esters of saturated aliphatic polycarboxylic acids (up to 10 carbon atoms per acid group), such as dialkyl oxalate, dialkyl malonate, dialkyl succinate, dialkyl glutarate, dialkyl adipate, dialkyl pimelate, dialkyl suberate, dialkyl azelate, dialkyl sebacate and the like; saturated aliphatic ketones such as diacetonealcohol, methyl heptyl ketone;
aromatic dicarboxylic acid esters such as dialkyl phthalate of from 4 to 13 carbon atoms per alkyl group as didecyl or dioctyl phthalate and the like; and non-reactive mixtures thereof. The term "polyoxyalkylene~
.
.. . .
_7_ 11~8~8~39 is meant to include compounds prepared by reacting ethylene oxide, propylene oxide and/or butyl oxide together with or without other co-reac-tants as alcohols, as long as there is a-t least several ~ R - 0 ~ repeating linkages. It is to be appreciated that other non-reactive substances may be added as diluents or viscosity control agents to assist the fluidity of the liquid. A preferred liquid absorbing means is a 50-50 mixture by volume of didecyl phthalate and a polyoxyalkylene glycol (Ucon, LB - 65, Trademark of Union Carbide) having a vapor pressure of less than 0.01 mm Hg pressure @ 68F. (20C,).
It is preferred that the liquid absorbing means have as low a vapor pressure as possible. This will allow as little of the liquid to be volatilized as possible during the absorption of paint spray effluent.
The overall process of the present invention is - described in Fig. 1 wherein the gaseous effluent is formed at 10, which effluent is passed into a liquid absorbing means containing a liquid absorber described herein. The outlet of said liquid absorber permits the absorbed gaseous effluent to be passed to a reclamation zone 14. In the reclamation zone, the liquid absorber is separated from the gaseous effluent.
The liquid absorbing means is then recycled by means of line 16 back to the liquid absorber for subsequent utilization therein. The gaseous effluent which is primarily solvent from the liquid paint may then be used and re-processed in the manufacture of liquid paint 18. If the gaseous effluent formed at step 10 is other than paint solvent from the ~' application and drying of paint, the product resulting from reclamation of the liquid absorber would then be disposed.
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One type of liquid absorber apparatus that may be used in this invention is described and shown in Fig. 2 which is a schematic diagram of a cyclonic spray scrubber 20 having an air or yaseous inlet 22. The gas passing through inlet 22 is tangentially passed into the cyclonic chamber 24 which has a liquid inlet 26 and a liquid outlet 27. The inlet 26 permits the liquid absorber to be passed through a duct 28 and sprayed through the spray manifold sections 30 comprised of a plurality of nozzles. The top of the spray manifold is a core buster disc 32.
The gas effluent from the industrial process enters through the inlet 22 and circles around the cyclonic chamber coming in direct contact with the sprayed liquid absorber 34, which is a fine division of the liquid absorber permitting a high surface area for the air to come into contact therewith.
} A very high efficiency is achieved in that substantially all of the gaseous effluent containing undesirable pollutants is absorbed in the liquid phase with the remaining gas exiting through the anti-spin vanes 36. The liquid absorber is then collected at the outlet 27 for subsequent processing at the reclamation zone 14. The cyclonic chamber can be manufactured from any metal stable to the gaseous effluent, e.g., stainless steel, glass-lined metal chambers and the like. A series of cyclonic chambers may be used to purify the gaseous effluent in step-wise fashion by passing the effluent from each cyclonic chamber to the next.
Cyclonic spray scrubbers described herein are further described in Chemical Engineers Handbook, Fourth Edi-tion, at page 18-33 and following.
_ g _ bm:
The reclamation zone is primarily directed towards a means of separating the liquid absorber from the gaseous effluent which is absorbed therein. Any means may be employed to form the separation. Two principal techniques are preferred. One is a vacuum distillation and the second is the utilization of microfiltration. In the vacuum distillation, it is highly preferred that there be a large differential between the boiling point of the liquid absorber and the gaseous effluent absorbed therein. If the differential is at least 200F., then a high separation efficiency can be achieved.
A more efficient technique for separating the liquid absorber from the gaseous effluent may be through the utilization of membranes which facilitate a microfiltration approach. In other words, membranes are inserted in a ~' conduit through which the liquid passes. A low molecular weight substance will pass therethrough whiLe a higher molecular weight substance will be prevented from passing therethrough.
Having described the invention in its broad aspect, listed below are operative embodiments. All temperatures are in degrees, Fahrenheit, and all percentages are percentages by weight, unless otherwise indicated.
Examples At ambient temperature and pressure, air was bubbled through a bottle containing a typical acrylic paint solvent made up of a mixture of Cellosolve* acetate, butyl Cellosolve* acetate, acetone, aliphatic alcohols (up to C3) bm:
.
and aliphatic hydrocarbons (up to C~). The first bottle was connected to a second and that to a third bottle with a liquid absorber in each of the second and third bottles to a level of
During various industrlal processes, gaseous effluent is formed. Due to the increased concern with the atmospheric environment, various processes have been suggested to control the gaseous effluent introduced into the environment.
Increased research and development has been undertaken, especially with bm:
.' ~
.' :' , - , :
~08Z88g respect to the effluent resulting from the application of liquid paints containing organic solvents to various substrates such as automobiles, trucks and the like. One such process is that described in ~.S. patent 3,932,151, which relates to paint spray booth construction and control of excess atomized paint from the air in the vicinity of a spray-painting operation.
Another proposed solution to the problem of gaseous effluent control is a technique where the gaseous effluent is absorbed onto a high surface area of carbonaceous substance, such as activated carbon, The difficulty with such a procedure is that when it came time to remove the absorbed solvent, a vacuum stripping operat-ion was employed, which therefore produced a hazardous con-dition in that the solvent was explosive at such vapor con-centrations. To overcome this problem, water was applied to the activated carbon, thereby significantly decreasing the effectiveness of the activated carbon by substantially decreasing the surface area of the activated carbon. Such an approach is highly inefficient for large voIumes of gas-eous effluent.
In designing a process for the purification of gaseous effluent one must be particularly conscious of being able to re-claim the gaseous effluent in order to make the process economically desirable from an overall point of view.
,, ~
pg/~ - 2 -108Z8~39 Summary of the Invention Broadly speaking the problems of the prior art are overcome by the present invention which provides in a process for the purification of gaseous effluent resulting from the application of liquid paint, wherein liquid paint is applied to a substrate, thereby forming a gaseous effluent containing pollutants, said gaseous effluent containing at least a hydrocarbon solvent or an ; oxygenated solvent and prior to passing effluent to the - atmosphere, removing the pollutants from the gaseous effluent, the improvement comprising; in a zone spaced from that in which the spraying of the substrate takes place, absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially water immiscible and contains only the elements carbon, hydrogen a oxygen.
Brief Description of the Drawings Fig. 1 is a schematic diagram of the process of the present invention including the use of the solvent by-products;
Fig. 2 is a schematic view of a cyclonic spray scrubber which is a liquid absorber for the gaseous effluent.
Pg/'t ~ - 3 -'' '' ,' .
1~8Z889 Descri tion of Preferred Embodiments P
Industrial processes that the present application is directed towards are any processes where s~aseous effluent is formed, which effluent is deleterious to the environment. In particular, the most preferred process is the gaseous effluent formed from the application of liquid paint.
Liquid paint is used in its broadest terms to include materials that contain organic film-form~rs dissolved in organic solvents, with or without pigments~
coating compositions regardless of how formulated, Pg/~ 3A -.. . ' ~:
, ~.
.
.
~08Z889 whether a latex or an emulsion, a slurry, a suspension and the like providing the gaseous effluent resulting therefrom contains hydrocarbon and/or oxygenated paint solvents. The gaseous effluent formed from the application of paint not only inclu~es the application of the paint itself but the volatilization of the solvent from the liquid paint during the drying of the liquid paint. By "gas" is meant to include not only a gas phase effluent but also an atomized paint overspray formed during the application of the paint to a substrate.
10The most preferred gaseous effluent is one that contains solvents for liquid paint which solvents are a mixture of substances. In particular, a hydrocarbon substance and an oxygenated substance.
~iquid paints are normally comprised of a resin ; film-former (natural or synthetic), pigments and a liquid solvent. Suitable liquid paint solvents are aliphatic alcohols from 1 to 8 carbon atoms such as methanol, ethanol, isopropanol, n-butanol, octanol, and the like; aliphatic ketones such as acetone, methylethyl ketone, methylisobutyl ketone, diisobutyl ketone cyclohexanone and the like; esters such as short chain aliphatic acids reacted with short chain aliphatic alcohols where the total number of carbon atoms of the acid and the alcohol is approximately 12, such as ethylacetate, butyl acetate, and the like; hydrocarbon solvents such as those containing up to 12 carbon atoms, as hexane, octane, cyclohexane, xylene, toluene, benzene and the like; aliphatic ethers and the like such as Cellosolve ; -4-bm:
. .
' ' ..
(trademark of Union Carbide for ethylene glycol monoethyl ether), Cellosolve* acetate, butyl Cellosolve*, and butyl Cellosolve* acetate and the like.
By "oxygenated" is meant organic solvents such as those ~or paints that contain oxygen in the molecule of the solvent either as an alcohol, a portion of an acid, an ester, or an ether.
The paints or coating compositions with which the present invention is concerned are those cont~ining film-forming organic and natural resins such as hydrocarbon resins,epoxies (such as the reaction product of bisphenol and epichlorohydrin), acrylics, polyesters, polyurethanes, alkyds, vinyls, polyamides, ureas, melamines, polyimides, silicones, polybenzimidazole and the like.
In the application of liquid paint to a substrate, the paint is atomized, such as airless, by air or electrostatically. The paint overspray from the paint spray booth is collected in a water wash by a water curtain. The paint applied to the substrate is then dried by passing it through a heated chamber wherein the solvent is volatilized.
During both the application and the drying of the paint, gaseous effluent is formed.
Prior to passing the gaseous effluent to the atmosphere the effluent is then treated according to the process of the present invention which is to sparge or bubble, ; or pass the gaseous effluent into a liquid absorbing means, such as a liquid absorber which is a solvent for the gaseous effluent.
* Trademark bm:
.
~ .
.. ' ' The liquid absorber with gaseous effluent therein may be retained in a suitable reservoir or may be subsequently collected and re-claimed as desired. The advantage of using a liquid absorbing means is that it can be readily handled, pumped, stored and reclaimed.
In its broadest aspect, the present invention is concerned with utilizing in place of the water reservoir for paint collection or the water curtain as is used currently i~
paint spray booth operations, the liquid absorbing means as is described further. By having the liquid absorbing means of the present invention employed as the overspray wash or the reservoir for collection of paint overspray, one may simplify the total pollution control of an industrial plant. In this manner there need be no variation to the organic paint systems that are currently employed, for one is concerned not with modification of the paint system itself, bu~ rather the absorption of the gaseous effluent and the most efficient, economical reclamation of the liquid absorbing means.
In the normal operation of a paint spray booth water wash, there is a curtain of water which washes the walls of a painting zone or spray booth. The water may be sprayed onto the walls or somehow collect the paint overspray. It is contemplated by this invention that the water curtain would be replaced by a curtain of liquid absorbing means described herein. It is to be appreciated that a curtain of liquid absorbing means need not be employed bu-t rather any application technique such as spraying and the like which can collect the paint overspray.
., bm:
` ` ' ~
.
-B&P 74238 The liquid absorbing means of the presentinvention is one that is non-reactive wlth the gaseous effluent. In addition, the liquid absorbing means is one that is liquid and is substantially non-volatile at ambient temperatures and pressures as well as the temperatures and pressures in which the industrial process and the reclamation of the organic solvent is operable. The liquid absorbing means consists only of carbon, hydrogen and oxygen.
Suitable liquid absorbing ~eans are those having a vapor pressure of less than 1 mm Hg pressure at 68F. (20C.), most preferably less than 0.01 mm Hg.
Examples of said liquid absorbing means are polyoxyalkylene glycol, preferably of the structure HO ~ R - O~ H where R
m contains 2 to 4 carbon atoms and m ranges from 2 to 2000 as polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol; saturated aliphatic polyols having from 2 to 12 carbon atoms as glyc~rol, ethylene glycol; dibasic esters such as the dialkyl (up to 8 carbon atoms per group~ esters of saturated aliphatic polycarboxylic acids (up to 10 carbon atoms per acid group), such as dialkyl oxalate, dialkyl malonate, dialkyl succinate, dialkyl glutarate, dialkyl adipate, dialkyl pimelate, dialkyl suberate, dialkyl azelate, dialkyl sebacate and the like; saturated aliphatic ketones such as diacetonealcohol, methyl heptyl ketone;
aromatic dicarboxylic acid esters such as dialkyl phthalate of from 4 to 13 carbon atoms per alkyl group as didecyl or dioctyl phthalate and the like; and non-reactive mixtures thereof. The term "polyoxyalkylene~
.
.. . .
_7_ 11~8~8~39 is meant to include compounds prepared by reacting ethylene oxide, propylene oxide and/or butyl oxide together with or without other co-reac-tants as alcohols, as long as there is a-t least several ~ R - 0 ~ repeating linkages. It is to be appreciated that other non-reactive substances may be added as diluents or viscosity control agents to assist the fluidity of the liquid. A preferred liquid absorbing means is a 50-50 mixture by volume of didecyl phthalate and a polyoxyalkylene glycol (Ucon, LB - 65, Trademark of Union Carbide) having a vapor pressure of less than 0.01 mm Hg pressure @ 68F. (20C,).
It is preferred that the liquid absorbing means have as low a vapor pressure as possible. This will allow as little of the liquid to be volatilized as possible during the absorption of paint spray effluent.
The overall process of the present invention is - described in Fig. 1 wherein the gaseous effluent is formed at 10, which effluent is passed into a liquid absorbing means containing a liquid absorber described herein. The outlet of said liquid absorber permits the absorbed gaseous effluent to be passed to a reclamation zone 14. In the reclamation zone, the liquid absorber is separated from the gaseous effluent.
The liquid absorbing means is then recycled by means of line 16 back to the liquid absorber for subsequent utilization therein. The gaseous effluent which is primarily solvent from the liquid paint may then be used and re-processed in the manufacture of liquid paint 18. If the gaseous effluent formed at step 10 is other than paint solvent from the ~' application and drying of paint, the product resulting from reclamation of the liquid absorber would then be disposed.
bm:
:
One type of liquid absorber apparatus that may be used in this invention is described and shown in Fig. 2 which is a schematic diagram of a cyclonic spray scrubber 20 having an air or yaseous inlet 22. The gas passing through inlet 22 is tangentially passed into the cyclonic chamber 24 which has a liquid inlet 26 and a liquid outlet 27. The inlet 26 permits the liquid absorber to be passed through a duct 28 and sprayed through the spray manifold sections 30 comprised of a plurality of nozzles. The top of the spray manifold is a core buster disc 32.
The gas effluent from the industrial process enters through the inlet 22 and circles around the cyclonic chamber coming in direct contact with the sprayed liquid absorber 34, which is a fine division of the liquid absorber permitting a high surface area for the air to come into contact therewith.
} A very high efficiency is achieved in that substantially all of the gaseous effluent containing undesirable pollutants is absorbed in the liquid phase with the remaining gas exiting through the anti-spin vanes 36. The liquid absorber is then collected at the outlet 27 for subsequent processing at the reclamation zone 14. The cyclonic chamber can be manufactured from any metal stable to the gaseous effluent, e.g., stainless steel, glass-lined metal chambers and the like. A series of cyclonic chambers may be used to purify the gaseous effluent in step-wise fashion by passing the effluent from each cyclonic chamber to the next.
Cyclonic spray scrubbers described herein are further described in Chemical Engineers Handbook, Fourth Edi-tion, at page 18-33 and following.
_ g _ bm:
The reclamation zone is primarily directed towards a means of separating the liquid absorber from the gaseous effluent which is absorbed therein. Any means may be employed to form the separation. Two principal techniques are preferred. One is a vacuum distillation and the second is the utilization of microfiltration. In the vacuum distillation, it is highly preferred that there be a large differential between the boiling point of the liquid absorber and the gaseous effluent absorbed therein. If the differential is at least 200F., then a high separation efficiency can be achieved.
A more efficient technique for separating the liquid absorber from the gaseous effluent may be through the utilization of membranes which facilitate a microfiltration approach. In other words, membranes are inserted in a ~' conduit through which the liquid passes. A low molecular weight substance will pass therethrough whiLe a higher molecular weight substance will be prevented from passing therethrough.
Having described the invention in its broad aspect, listed below are operative embodiments. All temperatures are in degrees, Fahrenheit, and all percentages are percentages by weight, unless otherwise indicated.
Examples At ambient temperature and pressure, air was bubbled through a bottle containing a typical acrylic paint solvent made up of a mixture of Cellosolve* acetate, butyl Cellosolve* acetate, acetone, aliphatic alcohols (up to C3) bm:
.
and aliphatic hydrocarbons (up to C~). The first bottle was connected to a second and that to a third bottle with a liquid absorber in each of the second and third bottles to a level of
2". The air with entrained gaseous effluent from the first bot:tle was passed into bottles 2 and 3 under the surface of the liquid therein. Listed on the following page in Table I
is a recital of the various liquid absorbing means used and the percentage of gaseous effluent recovered at each stage.
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is a recital of the various liquid absorbing means used and the percentage of gaseous effluent recovered at each stage.
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Claims (21)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the purification of gaseous effluent resulting from the application of liquid paint comprising the steps:
1. spraying a liquid paint onto a substrate thereby forming a gaseous effluent containing pollutants, said gaseous effluent containing at least a hydrocarbon solvent or an oxygenated solvent; and 2. in a zone spaced from that in which step 1 is performed, absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially non-volatile at ambient temperature and pressure, is substantially water immiscible and contains only the elements carbon, hydrogen and oxygen.
2. The process of claim 1 further comprising re-claiming said gas absorbing means by separating said gaseous effluent therefrom.
3. The process of claim 1 wherein the gaseous effluent contains entrained atomized droplets of a hydrocarbon solvent and an oxygenated solvent, said solvents being solvents for liquid paint.
4. The process of claim 1 wherein the liquid absorber has a vapor pressure of less than 1 mm Hg pressure @ 68°F.
(20°C.).
(20°C.).
5. The process of claim 1 wherein the liquid absorber has a vapor pressure af less than 0.01 mm Hg pressure @ 68°F.
(20°C.).
(20°C.).
6. The process of claim 1 wherein the liquid absorber for said gas is independently selected from the group consisting of polyoxyalkylene glycol, saturated aliphatic polyols, dialkyl ester of a saturated aliphatic polycarboxylic acid, saturated aliphatic ketone, aromatic dicarboxylic acid esters and non-reactive mixtures thereof.
7. The process of claim 1 wherein the liquid absorber is a mixture of a polyoxyalkylene glycol and a dialkyl phthalate.
8. The process of claim 1 wherein the liquid absorber is comprised of a polyoxyalkylene glycol.
9. The process of claim 1 wherein the passing of the gas into the gas absorbing means is performed by finely dividing the gas absorbing means and contacting the gaseous effluent with the finely divided gas absorbing means.
10. A process for the purification of gaseous effluent resulting from the application of liquid paint comprising the steps:
1. spraying a liquid paint onto a substrate thereby forming a gaseous effluent containing pollutants, said gaseous effluent containing at least a hydrocarbon solvent or an oxygenated solvent;
2. prior to passing the gaseous effluent to the atmosphere, in a zone spaced from that in which step 1 is performed, absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially non-volatile at ambient temperature and pressure, is substantially water immiscible and contains only the elements carbon, hydrogen oxygen; and 3. thereafter passing the gaseous effluent without the pollutants to the atmosphere.
1. spraying a liquid paint onto a substrate thereby forming a gaseous effluent containing pollutants, said gaseous effluent containing at least a hydrocarbon solvent or an oxygenated solvent;
2. prior to passing the gaseous effluent to the atmosphere, in a zone spaced from that in which step 1 is performed, absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially non-volatile at ambient temperature and pressure, is substantially water immiscible and contains only the elements carbon, hydrogen oxygen; and 3. thereafter passing the gaseous effluent without the pollutants to the atmosphere.
11. The process of claim 10 wherein the gaseous effluent pollutants are desorbed from the non-reactive liquid solvent by reclaiming liquid solvent by separating the absorbed pollutants therefrom, wherein the pollutant in the gaseous effluent is an oxygenated solvent for the liquid paint and wherein the non-reactive liquid solvent has a vapor pressure of less than 1 mm Hg pressure at 68°F
(20°C) and is comprised of a polyoxyalkylene glycol.
(20°C) and is comprised of a polyoxyalkylene glycol.
12. In a process for the purification of gaseous effluent resulting from the application of liquid paint, wherein liquid paint is applied to a substrate, thereby forming a gaseous effluent containing pollutants, said gaseous effluent containing at least a hydrocarbon solvent or an oxygenated solvent and prior to passing effluent to the atmosphere, removing the pollutants from the gaseous effluent, the improvement comprising;
in a zone spaced from that in which the spraying of the substrate takes place, absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially water immiscible and contains only the elements carbon, hydrogen a oxygen.
in a zone spaced from that in which the spraying of the substrate takes place, absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially water immiscible and contains only the elements carbon, hydrogen a oxygen.
13. The process of claim 12 further comprising reclaiming said non-reactive liquid solvent by separating said gaseous effluent therefrom.
14. The process of claim 12 wherein the gaseous effluent contains entrained atomized droplets of a hydrocarbon solvent and an oxygenated solvent, said solvents being solvents for liquid paint.
15. The process of claim 12 wherein the liquid solvent has a vapor pressure of less than 1 mm Hg at 68°F (20°C).
16. The process of claim 12 wherein the liquid solvent has a vapor pressure of less than 0.01 mm Hg at 68°F (20°C).
17. The process of claim 12 wherein the liquid solvent for said gas is independently selected from the group consisting of polyoxyalkylene glycol, saturated aliphatic polyols, dialkyl ester of a saturated aliphatic poly-carboxylic acid, saturated aliphatic ketone, aromatic dicarboxylic acid esters and non-reactive mixtures thereof.
18. The process of claim 12 wherein the liquid solvent is comprised of a polyoxyalkylene glycol.
19. The process of claim 12 wherein the passing of the gas into the non-reactive liquid solvent is performed by finely dividing the liquid solvent and contacting the gaseous effluent with the finely divided liquid solvent.
20. The process of claim 12 wherein the liquid solvent is comprised of the reaction product of butanol and propylene oxide.
21. In a process for the purification of gaseous effluent resulting from the application of liquid paint, wherein liquid paint is applied to a substrate, thereby forming a gaseous effluent containing pollutants, said gaseous effluent containing at least a hydrocarbon solvent or an oxygenated solvent and prior to passing the effluent to the atmosphere, removing the pollutants from the gaseous effluent, the improvement comprising;
absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially non-volatile at ambient tempera-ture and pressure, is substatially water immiscible and contains only the elements carbon, hydrogen and oxygen, and is a mixture of a polyoxyalkylene glycol and a dialkyl phthalate.
absorbing the pollutants in the gaseous effluent by passing the gaseous effluent into a non-reactive liquid solvent for said gaseous pollutants, wherein said liquid solvent is substantially non-volatile at ambient tempera-ture and pressure, is substatially water immiscible and contains only the elements carbon, hydrogen and oxygen, and is a mixture of a polyoxyalkylene glycol and a dialkyl phthalate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US73920376A | 1976-11-08 | 1976-11-08 | |
| US739,203 | 1976-11-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1082889A true CA1082889A (en) | 1980-08-05 |
Family
ID=24971255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA290,381A Expired CA1082889A (en) | 1976-11-08 | 1977-11-07 | Process for the purification of gaseous effluent from industrial processes |
Country Status (18)
| Country | Link |
|---|---|
| JP (1) | JPS5395176A (en) |
| AU (1) | AU510838B2 (en) |
| BE (1) | BE860563A (en) |
| BR (1) | BR7707131A (en) |
| CA (1) | CA1082889A (en) |
| DE (1) | DE2748194A1 (en) |
| DK (1) | DK493577A (en) |
| ES (1) | ES463957A1 (en) |
| FI (1) | FI773181A (en) |
| FR (1) | FR2369865A1 (en) |
| GB (1) | GB1565318A (en) |
| IT (1) | IT1088030B (en) |
| NL (1) | NL7712259A (en) |
| NO (1) | NO773767L (en) |
| NZ (1) | NZ185638A (en) |
| PH (1) | PH13448A (en) |
| SE (1) | SE7712202L (en) |
| ZA (1) | ZA776644B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5433288A (en) * | 1977-08-19 | 1979-03-10 | Nippon Shokubai Kagaku Kogyo Co Ltd | Removing method for organic compounds in exhaust gas |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8600C (en) * | 1900-01-01 | |||
| DE207554C (en) * | ||||
| NL15448C (en) * | 1900-01-01 | |||
| FR502957A (en) * | 1916-07-08 | 1920-05-31 | Aristide Daniel | Process for the recovery of one or the other, of two or more of the volatile substances: ether, alcohol, benzine, acetone, contained in gas mixtures |
| FR503728A (en) * | 1917-05-25 | 1920-06-16 | Jean Henry Bregeat | Process for recovering industrial volatile solvents |
| FR22395E (en) * | 1917-11-29 | 1921-07-01 | Jean Henry Bregeat | Process for recovering industrial volatile solvents |
| DE726287C (en) * | 1939-05-16 | 1942-10-09 | Platen Munters Refrigerating S | Process for depositing oil or lacquer colors, varnishes or the like when spray painting objects |
| JPS5110610A (en) * | 1974-07-15 | 1976-01-28 | Koyo Shoji Kk | SAHOOTOTSUKYUATSUJATSUKI |
| JPS5143374A (en) * | 1974-10-11 | 1976-04-14 | Showa Oil | Kihatsuseino tankasuisoo fukumu gasuno jokahoho |
| DE2451157C3 (en) * | 1974-10-28 | 1983-05-19 | Aluminium Norf Gmbh, 4040 Neuss | Process for cleaning exhaust air produced in large quantities during the operation of rolling stands |
| JPS51120972A (en) * | 1975-04-16 | 1976-10-22 | Kikuo Shiba | Exhaust gas purifying method and its device |
-
1977
- 1977-10-07 PH PH20308A patent/PH13448A/en unknown
- 1977-10-25 BR BR7707131A patent/BR7707131A/en unknown
- 1977-10-25 FI FI773181A patent/FI773181A/en not_active Application Discontinuation
- 1977-10-27 DE DE19772748194 patent/DE2748194A1/en not_active Withdrawn
- 1977-10-28 SE SE7712202A patent/SE7712202L/en not_active Application Discontinuation
- 1977-11-02 GB GB45585/77A patent/GB1565318A/en not_active Expired
- 1977-11-03 NO NO773767A patent/NO773767L/en unknown
- 1977-11-03 AU AU30318/77A patent/AU510838B2/en not_active Expired
- 1977-11-07 NZ NZ185638A patent/NZ185638A/en unknown
- 1977-11-07 NL NL7712259A patent/NL7712259A/xx not_active Application Discontinuation
- 1977-11-07 ZA ZA00776644A patent/ZA776644B/en unknown
- 1977-11-07 FR FR7733431A patent/FR2369865A1/en not_active Withdrawn
- 1977-11-07 DK DK493577A patent/DK493577A/en unknown
- 1977-11-07 CA CA290,381A patent/CA1082889A/en not_active Expired
- 1977-11-07 BE BE182418A patent/BE860563A/en not_active IP Right Cessation
- 1977-11-07 IT IT29370/77A patent/IT1088030B/en active
- 1977-11-08 ES ES463957A patent/ES463957A1/en not_active Expired
- 1977-11-08 JP JP13314677A patent/JPS5395176A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| FI773181A (en) | 1978-05-09 |
| IT1088030B (en) | 1985-06-04 |
| PH13448A (en) | 1980-04-23 |
| BE860563A (en) | 1978-03-01 |
| FR2369865A1 (en) | 1978-06-02 |
| AU510838B2 (en) | 1980-07-17 |
| NO773767L (en) | 1978-05-09 |
| JPS5395176A (en) | 1978-08-19 |
| DE2748194A1 (en) | 1978-05-11 |
| AU3031877A (en) | 1979-06-07 |
| NZ185638A (en) | 1979-11-01 |
| ES463957A1 (en) | 1978-07-01 |
| SE7712202L (en) | 1978-05-09 |
| ZA776644B (en) | 1978-08-30 |
| GB1565318A (en) | 1980-04-16 |
| DK493577A (en) | 1978-05-09 |
| NL7712259A (en) | 1978-05-10 |
| BR7707131A (en) | 1978-08-01 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |