CA1070482A - Decomposition of halogenated organic compounds - Google Patents
Decomposition of halogenated organic compoundsInfo
- Publication number
- CA1070482A CA1070482A CA260,819A CA260819A CA1070482A CA 1070482 A CA1070482 A CA 1070482A CA 260819 A CA260819 A CA 260819A CA 1070482 A CA1070482 A CA 1070482A
- Authority
- CA
- Canada
- Prior art keywords
- organic compounds
- temperature
- halogenated organic
- halogenated
- platinum
- 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
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8659—Removing halogens or halogen compounds
- B01D53/8662—Organic halogen compounds
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B7/00—Halogens; Halogen acids
- C01B7/01—Chlorine; Hydrogen chloride
Abstract
DECOMPOSITION OF HALOGENATED
ORGANIC COMPOUNDS
Abstract of the Disclosure A method for decomposing halogenated organic compounds which comprises: (a) preheating the halogenated organic compound to a temperature above about 300°C. and (b) contacting the preheated organic compound with a platinum catalyst in the presence of an oxidizing agent at a tem-perature of at least 350°C. The process converts the major part of the halide in the organic halide to hydrogen halide.
ORGANIC COMPOUNDS
Abstract of the Disclosure A method for decomposing halogenated organic compounds which comprises: (a) preheating the halogenated organic compound to a temperature above about 300°C. and (b) contacting the preheated organic compound with a platinum catalyst in the presence of an oxidizing agent at a tem-perature of at least 350°C. The process converts the major part of the halide in the organic halide to hydrogen halide.
Description
10~0~8~
Field of the Invention Briefly, the invention is in the field of decomposing halogenated organic compounds. More specifically, the invention is in the field of removal of vinyl halides (e.g., by the decom-position thereof) from gas streams.
Backqround Polyvinylchloride, which is prepared by the polymeri-zation of vinyl chloride, is one of the most useful of modern commerical plastics. Unfortunately, it i~ now believed to be well-established that vinyl chloride in sufficient concentration is harmful. In view of this, extensive research is now being conducted on methods of decomposing, or removing, vinyl chloride.
Our invention is directed to a method for decomposing a vinyl halide, such as vinyl chloride. More specifically, our invention is directed to a method of decomposing a vinyl halide, such as vinyl chloride, when present in an oxygen-containing gas stream such as air.
While decomposition of vinyl chloride is an important use for our method, it is readily apparent that the method is also useful for decomposing other halogenated organic compounds, as defined hereinafter.
Field of the Invention Briefly, the invention is in the field of decomposing halogenated organic compounds. More specifically, the invention is in the field of removal of vinyl halides (e.g., by the decom-position thereof) from gas streams.
Backqround Polyvinylchloride, which is prepared by the polymeri-zation of vinyl chloride, is one of the most useful of modern commerical plastics. Unfortunately, it i~ now believed to be well-established that vinyl chloride in sufficient concentration is harmful. In view of this, extensive research is now being conducted on methods of decomposing, or removing, vinyl chloride.
Our invention is directed to a method for decomposing a vinyl halide, such as vinyl chloride. More specifically, our invention is directed to a method of decomposing a vinyl halide, such as vinyl chloride, when present in an oxygen-containing gas stream such as air.
While decomposition of vinyl chloride is an important use for our method, it is readily apparent that the method is also useful for decomposing other halogenated organic compounds, as defined hereinafter.
- 2 -~o~
Prior Art Bas~d on search~s in the general area of decom-~osin~ vinyl chloride, in the opinion of the agent preparing this application, the most pertinent art is believed to be the following.
An article by Bond and Sadeghi (J. Appl. Chem., Biotechnol, 25, 241 (1975)) teaches the catalytic destruction of chlorinated hydrocarbon~ using a Pt-alumina catalyst.
The article teaches that a hydrocarbon fuel is required for those molecules containing more chlorine atoms than hydrogen atoms. However, all of the examples in the article use a hydrocarbon fuel. Moreover, the article contains no teachings of preheating the feedstock prior to passing it through the reactor.
The catalytic cleavage of ethyl chloride by platinum metal is described by the following references: -Dokl. Akad. Nank 5SSR 200 1105-b (1971) C.A. 76:14867 u Chemiker Ztz 88, 15-16 (1964) C.A. 60:750~-b ~owever, the following art teaches that halogen-containing compounds are poisonous to platinum oxidation catalysts:
"Industrial Pollution Control Handbook" edited by H. F. Lund, McGraw-Hill, 1971, Chapters 5, 7, and 14.
In summary, the art does not teach the advantages obtained by preheating the feedstock as described by Appli-cants' invention.
~ 070 Brief Summary of the Invention Broadly stated, the present invention is directed to a method for decomposing halogenated organic compounds wherein the method comprises:
(a) heating the halogenated organic compound to a temperature above about 300C.
(b) contacting the heated organic compound with a platinum catalyst in the presence of an oxidizing agent at a temperature of at least 350C.
In one aspect, the present invention is directed to a method for decomposing halogenated organic compounds, wherein the method comprises:
(a) heating a gaseous stream comprising said halogenated organic compounds and an oxidizing gas to a temperature above about 300C., (b) passing the heated gaseous stream of step (a) through a heated zone wherein it contacts a platinum catalyst, at a temperature of at least 350C., said process being characterized further in that said halogenated organic compound and said oxidizing gas are the only reactive components.
In a preferred embodiment, the halogenated organic compound is vinyl chloride and the oxidizing gas is air or a mixture of nitrogen and oxygen.
Detailed Description Materials Suita~le halogenated organic compounds for use in our process are those containing 1 to 4 carbon atoms and t~r70~
containing at least as many hydrogen atoms as halogen atoms.
Also suitable are mixtures of halogenated organic compounds containing 1 to 4 carbon atoms wherein the total number of hydrogen atoms in the mixture is at least equal to the total number of halogen atoms. Particularly suitable halogenated organic compounds are unsaturated organic compounds such as the vinyl halides and mixtures of Cl halogenated compounds and C2 halogenated compounds containing vinyl halides, wherein in said mixtures the total number of hydrogen atoms is at least equal to the total number of halogen atoms. The preferred halogenated organic compounds are those wherein the halogen is chlorine. Using chlorine as a typical halogen, examples of suitable halogenated organic compounds are materials represented by the formulae CH3Cl, CH2C12, CH3CHC12, CH2Cl CH2Cl, CH2 = CHC1, CH3CH = CHCl, CH3CH2CH =
CHCl.
From the foregoing description, it is understood that the halogenated organic compounds contain only carbon, hydrogen, and halogen.
The catalyst employed in the method of this inven-tion i8 platinum. The platinum may be in the form of finely - divided metallic platinum or in the form of platinum coated or impregnated on a non-oxidizing carrier as a support.
Generally, any of the non-oxidizing carriers normally employed with noble metal catalysts may be used. Alumina is particularly desirable although SiO2, SiC, Fe203 and kiesel-guhr including diatomaceous earth are also desirable.
1070~
r ,atinum impreynated on an alumina carrier support is the preferred catalyst form.
These catalytic forms of platinum are readily available through commercial sources and are well known in the art. In particular, the supported forms of the catalyst are conventionally used in petroleum reforming processes. These catalysts contain from 0.1 to 1.0%, more usually from 0.4 to 0.6%, by weight of platinum. In addition, they usually contain a small amount (e.g., 0.1 to 0.3%) of halogen such as chlorine.
The following U.S. patents teach methods of preparing suitable platinum catalysts: 2,898,289; 2,909,481; and 2,940,924.
A typical example of a suitable catalyst is "Houdry 3K"
(trade mark) catalyst which is available from Air Products and Chemicals. This catalyst has the following properties:
Pt, wt. % - 0.5-0.6 Cl, wt. % - 0.2 Bulk density - 0.64-0.69 g/cc Surface area - 250 sq. meters/gm.
Form - 1.6-3.2 mm. extrudate Suitable oxidizing gases include air, oxygen, and mixtures of nitrogen and oxygen.
Process Conditions An important feature of our process is heating the halogenated organic compound prior to passing it into the reactor zone where it is contacted with the catalyst. The oxidation of the halogenated organic compound in the presence 1 ~ 7 ~
o~ th(~ cata]yst i~ ~xothermic but doe~ not proceed spon-taneously. ln order that the reaction occur when contacted with catalyst, it is necessary to have the halogenated 7 organic compound at some minimum elevated temperature before contacting with the catalyst. (Persons skilled in this art often call this step "preheating.") This particular heating step should be conducted using a temperature above about 300C. more suitably above 320C., and preferably above 340C. The maximum temperature for this heating step is ~0 about 600C., preferably about 500C.
We have found that this preheating improves the life of the catalyst and provides a more efficient decom-position of the hal~genated organic compound. Moreover, it has been found that attempts to conduct the process by ~5 simply heating the reactants to the necessary temperatures in the reaction zone without preheating results in the catalyst being quickly rendered ineffective due to deposi-tion of carbon and carbon-containing compounds. This i8 particularly true when vinyl chloride is the halogenated ~0 organic compound being decomposed.
The heated halogenated organic compound is then passed to a reaction zone containing the catalyst. Since the reaction is exothermic, the temperature in the reaction zone varies, with the highest temperature suitably being in the range of about 350 to about 600C., preferably in the range of about 400 to about 500C. ~The highest temperature in the reaction zone is often referred to as "hot spot"
temperature).
i~70~
Our process is particularly suitable for use with air (or a mixture of nitrogen and oxygen) containing the halogenated organic compound (e.g., vinyl chloride) wherein the halogenated organic compound can be present over a wide range. In order to provide a more specific teaching, the GHSV ~gas hourly space velocity) of gas including halogenated organic compound to catalyst can be in the range of 100 to 100,000 l/hr.
While it is believed t~ be implied from the foregoing, it may be well to state that our invention is also applicable to processes wherein liquid halogenated organic compounds are vaporized and injected into the oxidizinq gas.
Our process has the particular advantage that over 99% of the halogen in the halogenated organic compound is converted to hydrogen halide. This is advantageous in that hydrogen halide is more readily absorbed in water than is halogen gas~
Our process has the further advantage that addi-tional hydrocarbons are not required as fuel in order to convert the halogen to a hydrogen halide.
Usually the effluent from the reactor i~ passed through a scrubber in order to absorb the hydrogen halide decomposition product.
In order to illustrate the nature of the present invention still more clearly, the following examples will be given. It is to be understood, however, that the invention is not to be limited to the specific conditions or details set forth in these examples except insofar as such limitations
Prior Art Bas~d on search~s in the general area of decom-~osin~ vinyl chloride, in the opinion of the agent preparing this application, the most pertinent art is believed to be the following.
An article by Bond and Sadeghi (J. Appl. Chem., Biotechnol, 25, 241 (1975)) teaches the catalytic destruction of chlorinated hydrocarbon~ using a Pt-alumina catalyst.
The article teaches that a hydrocarbon fuel is required for those molecules containing more chlorine atoms than hydrogen atoms. However, all of the examples in the article use a hydrocarbon fuel. Moreover, the article contains no teachings of preheating the feedstock prior to passing it through the reactor.
The catalytic cleavage of ethyl chloride by platinum metal is described by the following references: -Dokl. Akad. Nank 5SSR 200 1105-b (1971) C.A. 76:14867 u Chemiker Ztz 88, 15-16 (1964) C.A. 60:750~-b ~owever, the following art teaches that halogen-containing compounds are poisonous to platinum oxidation catalysts:
"Industrial Pollution Control Handbook" edited by H. F. Lund, McGraw-Hill, 1971, Chapters 5, 7, and 14.
In summary, the art does not teach the advantages obtained by preheating the feedstock as described by Appli-cants' invention.
~ 070 Brief Summary of the Invention Broadly stated, the present invention is directed to a method for decomposing halogenated organic compounds wherein the method comprises:
(a) heating the halogenated organic compound to a temperature above about 300C.
(b) contacting the heated organic compound with a platinum catalyst in the presence of an oxidizing agent at a temperature of at least 350C.
In one aspect, the present invention is directed to a method for decomposing halogenated organic compounds, wherein the method comprises:
(a) heating a gaseous stream comprising said halogenated organic compounds and an oxidizing gas to a temperature above about 300C., (b) passing the heated gaseous stream of step (a) through a heated zone wherein it contacts a platinum catalyst, at a temperature of at least 350C., said process being characterized further in that said halogenated organic compound and said oxidizing gas are the only reactive components.
In a preferred embodiment, the halogenated organic compound is vinyl chloride and the oxidizing gas is air or a mixture of nitrogen and oxygen.
Detailed Description Materials Suita~le halogenated organic compounds for use in our process are those containing 1 to 4 carbon atoms and t~r70~
containing at least as many hydrogen atoms as halogen atoms.
Also suitable are mixtures of halogenated organic compounds containing 1 to 4 carbon atoms wherein the total number of hydrogen atoms in the mixture is at least equal to the total number of halogen atoms. Particularly suitable halogenated organic compounds are unsaturated organic compounds such as the vinyl halides and mixtures of Cl halogenated compounds and C2 halogenated compounds containing vinyl halides, wherein in said mixtures the total number of hydrogen atoms is at least equal to the total number of halogen atoms. The preferred halogenated organic compounds are those wherein the halogen is chlorine. Using chlorine as a typical halogen, examples of suitable halogenated organic compounds are materials represented by the formulae CH3Cl, CH2C12, CH3CHC12, CH2Cl CH2Cl, CH2 = CHC1, CH3CH = CHCl, CH3CH2CH =
CHCl.
From the foregoing description, it is understood that the halogenated organic compounds contain only carbon, hydrogen, and halogen.
The catalyst employed in the method of this inven-tion i8 platinum. The platinum may be in the form of finely - divided metallic platinum or in the form of platinum coated or impregnated on a non-oxidizing carrier as a support.
Generally, any of the non-oxidizing carriers normally employed with noble metal catalysts may be used. Alumina is particularly desirable although SiO2, SiC, Fe203 and kiesel-guhr including diatomaceous earth are also desirable.
1070~
r ,atinum impreynated on an alumina carrier support is the preferred catalyst form.
These catalytic forms of platinum are readily available through commercial sources and are well known in the art. In particular, the supported forms of the catalyst are conventionally used in petroleum reforming processes. These catalysts contain from 0.1 to 1.0%, more usually from 0.4 to 0.6%, by weight of platinum. In addition, they usually contain a small amount (e.g., 0.1 to 0.3%) of halogen such as chlorine.
The following U.S. patents teach methods of preparing suitable platinum catalysts: 2,898,289; 2,909,481; and 2,940,924.
A typical example of a suitable catalyst is "Houdry 3K"
(trade mark) catalyst which is available from Air Products and Chemicals. This catalyst has the following properties:
Pt, wt. % - 0.5-0.6 Cl, wt. % - 0.2 Bulk density - 0.64-0.69 g/cc Surface area - 250 sq. meters/gm.
Form - 1.6-3.2 mm. extrudate Suitable oxidizing gases include air, oxygen, and mixtures of nitrogen and oxygen.
Process Conditions An important feature of our process is heating the halogenated organic compound prior to passing it into the reactor zone where it is contacted with the catalyst. The oxidation of the halogenated organic compound in the presence 1 ~ 7 ~
o~ th(~ cata]yst i~ ~xothermic but doe~ not proceed spon-taneously. ln order that the reaction occur when contacted with catalyst, it is necessary to have the halogenated 7 organic compound at some minimum elevated temperature before contacting with the catalyst. (Persons skilled in this art often call this step "preheating.") This particular heating step should be conducted using a temperature above about 300C. more suitably above 320C., and preferably above 340C. The maximum temperature for this heating step is ~0 about 600C., preferably about 500C.
We have found that this preheating improves the life of the catalyst and provides a more efficient decom-position of the hal~genated organic compound. Moreover, it has been found that attempts to conduct the process by ~5 simply heating the reactants to the necessary temperatures in the reaction zone without preheating results in the catalyst being quickly rendered ineffective due to deposi-tion of carbon and carbon-containing compounds. This i8 particularly true when vinyl chloride is the halogenated ~0 organic compound being decomposed.
The heated halogenated organic compound is then passed to a reaction zone containing the catalyst. Since the reaction is exothermic, the temperature in the reaction zone varies, with the highest temperature suitably being in the range of about 350 to about 600C., preferably in the range of about 400 to about 500C. ~The highest temperature in the reaction zone is often referred to as "hot spot"
temperature).
i~70~
Our process is particularly suitable for use with air (or a mixture of nitrogen and oxygen) containing the halogenated organic compound (e.g., vinyl chloride) wherein the halogenated organic compound can be present over a wide range. In order to provide a more specific teaching, the GHSV ~gas hourly space velocity) of gas including halogenated organic compound to catalyst can be in the range of 100 to 100,000 l/hr.
While it is believed t~ be implied from the foregoing, it may be well to state that our invention is also applicable to processes wherein liquid halogenated organic compounds are vaporized and injected into the oxidizinq gas.
Our process has the particular advantage that over 99% of the halogen in the halogenated organic compound is converted to hydrogen halide. This is advantageous in that hydrogen halide is more readily absorbed in water than is halogen gas~
Our process has the further advantage that addi-tional hydrocarbons are not required as fuel in order to convert the halogen to a hydrogen halide.
Usually the effluent from the reactor i~ passed through a scrubber in order to absorb the hydrogen halide decomposition product.
In order to illustrate the nature of the present invention still more clearly, the following examples will be given. It is to be understood, however, that the invention is not to be limited to the specific conditions or details set forth in these examples except insofar as such limitations
3~ are specified in the appended claims.
1~70~
In the following examples, the reactor, which was ~ ll cm. length of 1.3 cm. diameter stainless steel tube with 3.2 mm. thermocouple axially placed therein, was placed in a Lindburg furnace. A preheater, 20 cm. long 1.3 cm diameter stainless steel tube, preceded the reactor.
Five cc. of Houdry 3K reforming cataly-qt was placed in the reactor and occupied 7 cm. length of the reactor. This catalyst was 1.6 mm. extrudates and contained O.6% Pt and 0.2~ Cl impregnated on alumina.
The feed gas composition was as follows v/o: N2 ~
86-8; 2 ~ 11.2; C2H5Cl - 1.7; C2H3Cl - 0.13; ClC2H4Cl -0.079; C12 - 0.079; CHC13 - 0.033; CC14 - 0.018.
The composition of outlet gas was analyzed chroma-tographically using a flame ionization detector.
In all cases, the figure given for the reactor temperature is the highest temperature in the reactor zone.
This example shows the results of a serie~ of runs wherein the preheater temperature wa~ 322C. and the ~pace velocity and reactor temperature were varied. The results were as follows:
Space V~locityReactor lRCl~( )Total hr Temperature (C) (ppmv) ._ 1440 357 0.2 2400 396 0.2 3600 415 0.2 4800 437 0.2 (1)RCl = alkyl and alkylene chlorides 1070~8~
In thc outlet gas, the COC12 was less than 1 ppmv and the percent of chloride ending up as C12 was less than 0.2~.
In a series of runs, the preheater temperature was 300C. or below. The reactor temperature was 357C. and the space velocity was 2400 hr 1. The concentration of RCl in the outlet gas was above 10 ppmv in all runs thereby indi-cating that the catalyst was losing its effectiveness.
This run was made u~ing the following condition~:
Preheater Temperature - 322C.
Reactor Temperature - 375C.-550C
Space Velocity - 2400 hr 1 The total concentration of RCl was below 0.2 ppmv.
This example illu~trates the effect of preheater temperature on catalyst life.
At a space velocity of 2400 hr 1 and a preheater temperature of 343C., the total RCl concentration was below 0.2 ppmv after 240 hours of continuous operation at various conditions during which the catalyst underwent deactivation several times by either keeping the preheater below 300C.
or using less than stoichiometric amount of air.
The reactor temperature was between 357-437C.
during this run.
1.~70~
In the following examples larger apparatus was used.
Tho reactor was 33 cm. of 2.7 cm. diameter stain-l(s.s stcol ~ e containing a 3.2 mm. thermowell along the ~)ipe centerline. The preheater was comprised at a coil of 1.3 cm. tubing enclosed in an electrically heated furnace.
Electrical heating tapes were placed around the line from preheater to reactor and reactor itself to control their respective temperatures.
The reactor contained 170 cc. of Houdry 3K reforming catalyst, 0.6~ Pt and 0.2% Cl inpregnated on alumina.
The feed gas had the following composition v/o:
vinyl chloride - 0.2 to 0.6 nitrogen - about 96 oxygen - about 3.8 The composition of the reactor outlet gas was determined using chromatographic analysis with a ~lame ionization detector.
The chlorine determination was made using a conventional method.
EXAMPLE S
A series of runs was made wherein the space velocity, preheater temperature and reactor temperature were varied. The results are shown ~elow.
--. 11 --~ 07 0 ~ ~ ~
Space Vinyl Veloc~ty Preheater Reactor Chloride hr Temperature,C Temperature,C (ppmv)
1~70~
In the following examples, the reactor, which was ~ ll cm. length of 1.3 cm. diameter stainless steel tube with 3.2 mm. thermocouple axially placed therein, was placed in a Lindburg furnace. A preheater, 20 cm. long 1.3 cm diameter stainless steel tube, preceded the reactor.
Five cc. of Houdry 3K reforming cataly-qt was placed in the reactor and occupied 7 cm. length of the reactor. This catalyst was 1.6 mm. extrudates and contained O.6% Pt and 0.2~ Cl impregnated on alumina.
The feed gas composition was as follows v/o: N2 ~
86-8; 2 ~ 11.2; C2H5Cl - 1.7; C2H3Cl - 0.13; ClC2H4Cl -0.079; C12 - 0.079; CHC13 - 0.033; CC14 - 0.018.
The composition of outlet gas was analyzed chroma-tographically using a flame ionization detector.
In all cases, the figure given for the reactor temperature is the highest temperature in the reactor zone.
This example shows the results of a serie~ of runs wherein the preheater temperature wa~ 322C. and the ~pace velocity and reactor temperature were varied. The results were as follows:
Space V~locityReactor lRCl~( )Total hr Temperature (C) (ppmv) ._ 1440 357 0.2 2400 396 0.2 3600 415 0.2 4800 437 0.2 (1)RCl = alkyl and alkylene chlorides 1070~8~
In thc outlet gas, the COC12 was less than 1 ppmv and the percent of chloride ending up as C12 was less than 0.2~.
In a series of runs, the preheater temperature was 300C. or below. The reactor temperature was 357C. and the space velocity was 2400 hr 1. The concentration of RCl in the outlet gas was above 10 ppmv in all runs thereby indi-cating that the catalyst was losing its effectiveness.
This run was made u~ing the following condition~:
Preheater Temperature - 322C.
Reactor Temperature - 375C.-550C
Space Velocity - 2400 hr 1 The total concentration of RCl was below 0.2 ppmv.
This example illu~trates the effect of preheater temperature on catalyst life.
At a space velocity of 2400 hr 1 and a preheater temperature of 343C., the total RCl concentration was below 0.2 ppmv after 240 hours of continuous operation at various conditions during which the catalyst underwent deactivation several times by either keeping the preheater below 300C.
or using less than stoichiometric amount of air.
The reactor temperature was between 357-437C.
during this run.
1.~70~
In the following examples larger apparatus was used.
Tho reactor was 33 cm. of 2.7 cm. diameter stain-l(s.s stcol ~ e containing a 3.2 mm. thermowell along the ~)ipe centerline. The preheater was comprised at a coil of 1.3 cm. tubing enclosed in an electrically heated furnace.
Electrical heating tapes were placed around the line from preheater to reactor and reactor itself to control their respective temperatures.
The reactor contained 170 cc. of Houdry 3K reforming catalyst, 0.6~ Pt and 0.2% Cl inpregnated on alumina.
The feed gas had the following composition v/o:
vinyl chloride - 0.2 to 0.6 nitrogen - about 96 oxygen - about 3.8 The composition of the reactor outlet gas was determined using chromatographic analysis with a ~lame ionization detector.
The chlorine determination was made using a conventional method.
EXAMPLE S
A series of runs was made wherein the space velocity, preheater temperature and reactor temperature were varied. The results are shown ~elow.
--. 11 --~ 07 0 ~ ~ ~
Space Vinyl Veloc~ty Preheater Reactor Chloride hr Temperature,C Temperature,C (ppmv)
4,000 388 446 0.2 4,000 396 427 0.5 4,000 388 418 0.7 4,000 390 404 0.8
5,000 398 443 1.0 5,000 388 418 0.6 10 5,300 388 402 0.8 5,600 396 427 0.3
6,000 412 415 0.8 This example shows the effect of using a reactor temperature less than 400C. in this size reactor.
The space velocity was 5,000 hr 1, The preheater temperature, reactor temperature and vinyl chloride content for five runs are shown below.
Preheater Reactor Vinyl Chloride iOTemperature, C.Temperature, C. (ppmv) 398 443 ~.0 388 418 0.6 388 407 4.2 387 387 2~0 This example shows the effect of preheater tem-perature.
The space velocity was 5,000 hr 1 in both runs.
Run A - Using a preheater temperature of 300C., the reactor temperature reached only 310C., indicating no reaction was occurring. The concentration of vinyl chloride in the outlet gas was 2,000 ppm~ which was about the same as that of the feed gas. This further indicated that no reaction occurred.
10'~ 2 Run B - Using a preheater temperature of 330C. the tem-perature in the reactor reached 465C. The concentration of vinyl chloride in the outlet gas was in the range of 0.3 to 1.4 ppmv.
This example clearly illustrates the improvement of Applicant's invention. It shows that without added hydrogen fuel the reaction needs a preheater temperature above 300C.
This example shows that the catalyst has a long life in our method.
The preheater temperature was in the range of 391 to 413C.
The reactor temperature was in the range of 425 to 458C.
After 224 hours of operation at space velocities in the range of 4,000 to 6,000 hr 1, the concentration of vinyl chloride in the outlet gas was less than 1 ppmv.
Thus, having described the invention in detail, it 2~ will be understood by those skilled in the art that certain variations and modifications may be made without departing from the spirit and scope of the invention as defined herein and in the appended claims.
We claim:
The space velocity was 5,000 hr 1, The preheater temperature, reactor temperature and vinyl chloride content for five runs are shown below.
Preheater Reactor Vinyl Chloride iOTemperature, C.Temperature, C. (ppmv) 398 443 ~.0 388 418 0.6 388 407 4.2 387 387 2~0 This example shows the effect of preheater tem-perature.
The space velocity was 5,000 hr 1 in both runs.
Run A - Using a preheater temperature of 300C., the reactor temperature reached only 310C., indicating no reaction was occurring. The concentration of vinyl chloride in the outlet gas was 2,000 ppm~ which was about the same as that of the feed gas. This further indicated that no reaction occurred.
10'~ 2 Run B - Using a preheater temperature of 330C. the tem-perature in the reactor reached 465C. The concentration of vinyl chloride in the outlet gas was in the range of 0.3 to 1.4 ppmv.
This example clearly illustrates the improvement of Applicant's invention. It shows that without added hydrogen fuel the reaction needs a preheater temperature above 300C.
This example shows that the catalyst has a long life in our method.
The preheater temperature was in the range of 391 to 413C.
The reactor temperature was in the range of 425 to 458C.
After 224 hours of operation at space velocities in the range of 4,000 to 6,000 hr 1, the concentration of vinyl chloride in the outlet gas was less than 1 ppmv.
Thus, having described the invention in detail, it 2~ will be understood by those skilled in the art that certain variations and modifications may be made without departing from the spirit and scope of the invention as defined herein and in the appended claims.
We claim:
Claims (16)
1. A method for decomposing halogenated organic compounds, said halogenated organic compounds containing 1 to 4 carbon atoms and containing at least as many hydrogen atoms as halogen atoms, said method comprising:
(a) heating the halogenated organic compounds to a temperature above about 300°C., and (b) contacting the heated organic compound with a platinum catalyst in the presence of an oxidizing agent at a temperature of at least 350°C.
(a) heating the halogenated organic compounds to a temperature above about 300°C., and (b) contacting the heated organic compound with a platinum catalyst in the presence of an oxidizing agent at a temperature of at least 350°C.
2. The process of Claim 1 wherein the oxidizing agent is air or a mixture of nitrogen and oxygen.
3. The process of Claim 2 wherein the halogenated organic compounds are selected from the group consisting of vinyl halides and mixtures of C1 halogenated compounds and C2 halogenated compounds containing vinyl halides wherein the total number of hydrogen atoms in the mixture is at least equal to the total number of halogen atoms.
4. The process of Claim 3 wherein the halogen of said halogenated organic compounds is chlorine.
5. The process of Claim 4 wherein the temperature in step (a) is above 320°C and the temperature is step (b) is in the range of about 350°C to about 600°C.
6. The process of Claim 5 wherein the temperature of step (a) is above 340°C. and the temperature of step (b) is in the range of about 400°C. to about 500°C.
7. The process of Claim 6 wherein the catalyst is finely divided platinum, platinum coated on a non-oxidizing carrier, or platinum impregnated on a non-oxidizing carrier.
8. A method for decomposing halogenated organic compounds, said halogenated organic compounds containing 1 to 4 carbon atoms and containing at least as many hydrogen atoms as halogen atoms, said method comprising:
(a) heating a gaseous stream comprising said halogenated organic compounds and an oxidizing gas selected from air and a mixture of nitrogen and oxygen to a temperature above about 300°C., (b) passing the heated gaseous stream of step (a) through a heated zone wherein it contacts a platinum catalyst, at a temperature of at least 350°C., said process being characterized further in that at least 99 percent of the halogens present in the halogenated organic compounds are converted to hydrogen halides.
(a) heating a gaseous stream comprising said halogenated organic compounds and an oxidizing gas selected from air and a mixture of nitrogen and oxygen to a temperature above about 300°C., (b) passing the heated gaseous stream of step (a) through a heated zone wherein it contacts a platinum catalyst, at a temperature of at least 350°C., said process being characterized further in that at least 99 percent of the halogens present in the halogenated organic compounds are converted to hydrogen halides.
9. The process of Claim 8 characterized further in that said halogenated organic compounds and said oxidizing gas are the only reactive materials.
10. The process of Claim 9 wherein the halogenated organic compounds are selected from the group consisting of vinyl halides and mixtures of C1 halogenated compounds and C2 halogenated compounds containing vinyl halides wherein the total number of hydrogen atoms in the mixture is at least equal to the total number of halogen atoms.
11. The process of Claim 10 wherein the halogen of said halogenated organic compounds is chlorine.
12. The process of Claim 11 wherein the tem-perature in step (a) is above 320°C. and the temperature in step (b) is in the range of about 350°C. to about 600°C.
13. The process of Claim 12 wherein the tem-perature in step (a) is above 340°C. and the temperature in step (b) is in the range of about 400°C. to about 500°C.
14. The process of Claim 13 wherein the catalyst is finely divided platinum, platinum coated on a non-oxidizing carrier, or platinum impregnated on a non-oxidizing carrier.
15. The process of Claim 7 wherein the catalyst is platinum impregnated on a non-oxidizing carrier.
16. The process of Claim 15 wherein the non-oxidizing carrier is alumina.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US67942976A | 1976-04-22 | 1976-04-22 | |
| US05/696,169 US4059683A (en) | 1976-04-22 | 1976-06-14 | Decomposition of halogenated organic compounds |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1070482A true CA1070482A (en) | 1980-01-29 |
Family
ID=27102230
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA260,819A Expired CA1070482A (en) | 1976-04-22 | 1976-09-09 | Decomposition of halogenated organic compounds |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4059683A (en) |
| CA (1) | CA1070482A (en) |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3069081D1 (en) * | 1979-12-13 | 1984-10-04 | Ici Plc | Method of recovering bromine from methyl bromide |
| US5276250A (en) * | 1986-07-11 | 1994-01-04 | Hagenmaier Hans Paul | Process for decomposing polyhalogenated compounds |
| US5176897A (en) * | 1989-05-01 | 1993-01-05 | Allied-Signal Inc. | Catalytic destruction of organohalogen compounds |
| US5206003A (en) * | 1989-07-07 | 1993-04-27 | Ngk Insulators, Ltd. | Method of decomposing flow |
| JPH0663357A (en) * | 1990-10-26 | 1994-03-08 | Tosoh Corp | Device for treating waste gas containing organic halogen compounds |
| JPH0659387B2 (en) * | 1990-11-30 | 1994-08-10 | 正勝 平岡 | Exhaust gas purification method |
| EP0745561B1 (en) * | 1992-03-25 | 2000-05-24 | Kurita Water Industries Ltd. | Method of decomposing volatile organic halogenated compounds in water |
| US5490941A (en) * | 1992-03-25 | 1996-02-13 | Kurita Water Industries, Ltd. | Method of treatment of a fluid containing volatile organic halogenated compounds |
| US5283041A (en) * | 1992-08-13 | 1994-02-01 | Engelhard Corporation | Catalytic incineration of organic compounds |
| US5451388A (en) * | 1994-01-21 | 1995-09-19 | Engelhard Corporation | Catalytic method and device for controlling VOC. CO and halogenated organic emissions |
| US5578283A (en) * | 1994-12-30 | 1996-11-26 | Engelhard Corporation | Catalytic oxidation catalyst and method for controlling VOC, CO and halogenated organic emissions |
| US5720931A (en) * | 1995-07-21 | 1998-02-24 | Guild Associates, Inc. | Catalytic oxidation of organic nitrogen-containing compounds |
| US6509511B1 (en) | 1998-10-07 | 2003-01-21 | Guild Associates, Inc. | Process for the conversion of perfluoroalkanes, a catalyst for use therein and a method for its preparation |
| US6676913B2 (en) | 1996-06-12 | 2004-01-13 | Guild Associates, Inc. | Catalyst composition and method of controlling PFC and HFC emissions |
| US6069291A (en) * | 1996-06-12 | 2000-05-30 | Guild Associates, Inc. | Catalytic process for the decomposition of perfluoroalkanes |
| US5895636A (en) | 1997-12-02 | 1999-04-20 | Engelhard Corporation | Catalytic compositions and methods for suppression of halogenation of organic compounds with oxidation products of halogenated organic compounds in gaseous emission streams |
| US6673326B1 (en) | 2000-08-07 | 2004-01-06 | Guild Associates, Inc. | Catalytic processes for the reduction of perfluorinated compounds and hydrofluorocarbons |
| US7462339B2 (en) * | 2005-12-29 | 2008-12-09 | Basf Catalysts Llc | Metallic foam trap for poisons: aircraft ozone |
| US20090252664A1 (en) * | 2008-02-18 | 2009-10-08 | Applied Materials, Inc. | Methods and apparatus for heating reagents and effluents in abatement systems |
| US8475755B2 (en) * | 2009-08-21 | 2013-07-02 | Sub-Chemie Inc. | Oxidation catalyst and method for destruction of CO, VOC and halogenated VOC |
| US8889079B2 (en) * | 2010-01-13 | 2014-11-18 | Efb, Inc. | Apparatus for removal of particles and VOC from an airstream |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2340610A (en) * | 1939-05-04 | 1944-02-01 | Pittsburgh Plate Glass Co | Preparation of titanium dioxide |
| US3120427A (en) * | 1960-11-01 | 1964-02-04 | Thann Fab Prod Chem | Preparation of titanium dioxide |
| US3705010A (en) * | 1970-12-07 | 1972-12-05 | Dow Chemical Co | Recovery of bromine from organic bromides |
| GB1430568A (en) * | 1973-05-14 | 1976-03-31 | Mitsubihsi Chemical Ind Ltd | Method of decomposing halohydrocarbons |
-
1976
- 1976-06-14 US US05/696,169 patent/US4059683A/en not_active Expired - Lifetime
- 1976-09-09 CA CA260,819A patent/CA1070482A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4059683A (en) | 1977-11-22 |
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