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WO1997019729A1 - Procede et appareil d'epuration d'acide residuel - Google Patents

Procede et appareil d'epuration d'acide residuel Download PDF

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Publication number
WO1997019729A1
WO1997019729A1 PCT/CA1996/000778 CA9600778W WO9719729A1 WO 1997019729 A1 WO1997019729 A1 WO 1997019729A1 CA 9600778 W CA9600778 W CA 9600778W WO 9719729 A1 WO9719729 A1 WO 9719729A1
Authority
WO
WIPO (PCT)
Prior art keywords
acid
waste acid
stream
outer vessel
tube means
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.)
Ceased
Application number
PCT/CA1996/000778
Other languages
English (en)
Inventor
Saleh Witwit
Peter Groeneweg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PPG Architectural Coatings Canada Inc
Original Assignee
ICI Canada Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ICI Canada Inc filed Critical ICI Canada Inc
Publication of WO1997019729A1 publication Critical patent/WO1997019729A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
    • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
    • A62D3/38—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by oxidation; by combustion
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
    • A62D2101/20—Organic substances
    • A62D2101/26—Organic substances containing nitrogen or phosphorus
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
    • A62D2101/40—Inorganic substances
    • A62D2101/47—Inorganic substances containing oxygen, sulfur, selenium or tellurium, i.e. chalcogen
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2203/00—Aspects of processes for making harmful chemical substances harmless, or less harmful, by effecting chemical change in the substances
    • A62D2203/10—Apparatus specially adapted for treating harmful chemical agents; Details thereof

Definitions

  • the present invention relates to methods and apparatus for cleaning of organic compounds from waste sulfuric acid streams.
  • Waste acid streams contaminated with organic compounds have been a continuous concern to the industry for many years. Because of the undesirable environmental concerns about the presence of organics, the current options for handling waste acid streams are very limited and expensive. Further, low concentration of acids in such waste streams cause difficulties in recycling the same process, and add to the expense of handling and transportation.
  • the Pauling Process which uses a stirred vessel reactor at atmospheric pressure and a temperature of about 300°C.
  • the organics are partially destroyed and partially stripped away with the vapor.
  • a disadvantage of this system is that there is a high corrosion factor and a significant amount of maintenance required as a result, thus rendering the operating cost for this system very high.
  • the present invention provides a method of destroying organics in waste acid by heating the acid under at least its own vapor pressure to a temperature suitable to destroy the organics.
  • the invention also provides a novel continuous reactor, which may be used in a multi-stage process.
  • the waste acid is heated to a temperature of between 100°C and 350°C and subjected to at least its own vapor pressure.
  • the method of the invention may further comprise the step of adding an oxidizing agent to the waste acid.
  • the present invention provides a reactor for use in destroying organics in waste acid under pressure.
  • the reactor is useful in a continuous mode whereby a continuous stream of waste acid flows into the reactor and a continuous flow of purified acid flows out of the reactor.
  • the continuous stream of waste acid is pumped into an inlet on a pressurized elongate tube means.
  • the tube means has a pre-determined length and an outer periphery.
  • the inlet is located at one end of the tube means and leads to a remote end with an opening through which the acid stream flows.
  • the waste acid stream flows into an outer pressurized elongate vessel which is spaced from and surrounds the outer periphery of at least a portion of the predetermined length of the tube means.
  • the outer vessel has a closed first section adjacent the remote end of the tube means for receiving the acid stream and for reversely directing the stream toward a second section of the outer vessel spaced along the outer periphery of the tube means.
  • An outlet is formed in the second section of the outer vessel to allow the acid stream to continuously exit the outer vessel.
  • a heating means located external to the outer vessel and located adjacent to the closed first section of the outer vessel is used to heat the waste acid stream to a pre-determined temperature. The organic compounds are destroyed as the acid stream is heated under pressure to the pre-determined temperature. As the heated acid stream flows along the outer periphery of the tube means, the heat from the stream is transferred to the waste acid stream inside the tube means.
  • FIG. 1 is a schematic diagram illustrating a reactor for cleaning and concentrating acids according to the present invention.
  • Fig. 2 is a schematic diagram of a multi-stage process using the reactor.
  • the present invention provides a method of removing organic compounds from waste acid which is more efficient and less costly than presently known methods.
  • the use of pressure provides favorable reaction conditions which destroy the organic contaminants by keeping the reactant together and allowing the organics to be destroyed rather than stripped away.
  • a novel reactor useful for performing this acid cleaning method.
  • the invention provides a method of destroying organics in waste acid, permitting the reuse of the acids.
  • destroying refers to the conversion of contaminating organics to gas or vapor (e.g. , water, carbon dioxide and nitrogen oxide) .
  • gas or vapor e.g. , water, carbon dioxide and nitrogen oxide
  • the method of the invention is particularly well adapted for use with spent sulfuric acid (H 2 S0 4 ) streams.
  • the process of the invention involves heating the waste acid to a temperature between about 100°C and about 350°C.
  • the temperature is between about 120°C to about 300°C, and more preferably about 150°C to about
  • the reaction is not vented, and thus, the acid is subjected to increased pressure from the vapors resulting from the heating step.
  • the waste acid is subjected to at least its own vapor pressure during the heating.
  • the vapor pressure of the reaction is dependent upon the weight percentage of sulfuric acid in the acid stream.
  • a concentrated sulfuric acid waste stream may have a vapor pressure as low as about 10 pounds per square inch gauge (psig)
  • a stream having a low acid and/or high water content may have a much higher vapor pressure.
  • one of skill in the art may choose to subject the reaction to a pressure higher than its own vapor pressure.
  • Suitable pressures can be readily selected by one of skill in the art. Generally, a suitable pressure will be in the range between about 10 psig to about 500 psig, with a more preferred range being between about 100 - 200 psig, and most preferably about 100 - 150 psig.
  • an oxidizing agent may be added to the waste acid.
  • the method of the invention requires the consumption of a smaller quantity of oxidizing agent.
  • the oxidizing agent is nitric acid which is present in an amount of between about 0.1 to about 10%, and preferably between 0.1 to 5% by weight.
  • Other suitable oxidizing agents may be readily selected by one of skill in the art. Unlike prior art methods, there is no loss of the oxidizing agent in the method of the invention. Rather, under pressure the oxidizing agent remains in the acid.
  • the resulting product, treated (purified) acid can be directly reused or stored for future use.
  • the present invention provides a novel reactor, which is particularly well adapted for use in a continuous process of destroying organic compounds in a waste acid stream.
  • This reactor is not limited to use with the method of the invention, or for use in cleaning sulfuric acid streams. Rather, the reactor of the invention is generally useful where heating under pressure is desirable and/or where it is desirable for the "hot" zone of the reactor to be located remotely from the seal.
  • a continuous supply 10 of waste acid is supplied to reactor 12. After the acid 10 flows through reactor 12 in a continuous process, the acid is purified and exits through pressure control valve 14 to storage or flash evaporation 16.
  • the reactor 12 utilizes a unique reverse flow operation.
  • the acid 10 enters the reactor 12 at an inlet 18.
  • the inlet 18 is connected to a pressurized elongate tube means 20.
  • the tube means 20 is a single cylindrical elongate tube.
  • An alternate embodiment of inlet 18 may be a plurality or manifold of individual elongate cylindrical tubes (not shown) located adjacent one another, which may feed into the same or different locations in the tube means 20.
  • the pressurized elongate tube means extends from the inlet 18 at one end 22 a pre-determined length to a remote end 24.
  • the remote end 24 has an opening 28 through which the acid stream flows.
  • an outer pressurized elongate vessel 32 is spaced from and surrounds the outer periphery 30 along the length of the tube means 20. As shown in FIG. 1, the outer vessel 32 is concentric with the tube means 20. An alternate embodiment which is not shown is to have the outer vessel 32 extend along only a portion of the tube means 20.
  • the outer vessel 32 has a closed first section 34 which is adjacent the remote end 24 of the tube means 20 for receiving the waste acid stream 10 and for reversely directing the stream 10 along the outer periphery 30 of the tube means 20.
  • the outer vessel 32 has a second section 36 with an outlet 38 for allowing the acid stream 10 to continuously exit the reactor 12.
  • the waste acid stream 10 is heated in a heat reaction zone 40 which combines with the internal pressure of the reactor 12 to destroy the organic compounds in the acid stream.
  • a heating means 42 is located on an external side of the outer vessel 32 adjacent the closed first section 34.
  • the heating means can include, for example, a heating jacket, half pipes, hot baths such as oil hot baths and sand baths, or the use of microwave frequency radiation.
  • the reactor 12 of the present invention also provides pre-heating of the waste acid stream 10 before it enters the heat zone 40. This is accomplished by reversely flowing the heated acid stream 10 back along the outer periphery 30 of the tube means 20. As the heated acid stream 10 leaves the heat zone 40 and flows along the second section 36 of the outer vessel 32, the heat of the purified acid stream 10 is transferred to the incoming waste acid stream 10 flowing in tube means 20.
  • the tube means 20 and outer vessel 32 are filled with a packing 44 to continuously mix the flowing acid stream.
  • a packing 44 examples include rasching rings, pall rings, and intalox saddles made from glass or ceramic.
  • a seal 46 is used to seal the pressurized tube means 20 at the one end 22 and the outer vessel 32 at the second section 36. Since the heating means 42 is located a distance from the seal 46, the seal can advantageously be made out of commonly available materials and need not be capable of withstanding high temperatures. For example, suitable materials for the seal include Teflon ® and the like.
  • the reactor 12 could be used in a multi-stage process, as illustrated in Fig. 2. The number of stages depend on the kind of organics in the acid, the quality of the feed and the quality of the product required. Each stage consists of a pump 48, a reactor 12, and a flash evaporator 50.
  • Each flash evaporator 50 connects to the next stage's pump 50 and to a conduit 52 for flowing the vapor to a condenser (not shown) .
  • a condenser not shown
  • a reactor 12 of the present invention could include an inner tube means 20 with a predetermined length of about 475 mm, an inner diameter of about 10 mm, and an outer diameter of about 16 mm.
  • the tube means 20 can be manufactured from glass or merely lined with glass.
  • the outer vessel 32 can have a length of 480 mm, an inner diameter of about 25 mm and an outer diameter of 35 mm.
  • the outer vessel 32 can also be made of glass or lined with glass.
  • the spacing between the inner diameter of the outer vessel 32 and the outer diameter of the tubing 20 can be approximately 9.5 mm.
  • the tubing 20 is spaced from the outer vessel 32 through the use of several glass rasching rings.
  • the heating means 42 can be a hot oil bath with the oil heated by an electrical heater.
  • the hot oil bath can extend up the second section 36 of the outer vessel 32 approximately 13 mm.
  • the predetermined temperature applied to the acid stream can be in a range of 100°C to 350°C, and more preferably about 150°C to about 300°C.
  • the reactor can be designed to withstand internal pressures up to 500 psig, and preferably 100 - 150 psig at the pre-determined temperature.

Landscapes

  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

Procédé économique et efficace d'extraction de fractions organiques, et notamment de fractions aromatiques nitrées, de courants d'acide résiduel. Le procédé consiste à chauffer l'acide résiduel sous au moins sa propre pression de vapeur, facultativement en présence d'un agent oxydant. On a également prévu un nouveau réacteur continu utile dans ce procédé et pour diverses applications.
PCT/CA1996/000778 1995-11-28 1996-11-27 Procede et appareil d'epuration d'acide residuel Ceased WO1997019729A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US56344895A 1995-11-28 1995-11-28
US08/563,448 1995-11-28

Publications (1)

Publication Number Publication Date
WO1997019729A1 true WO1997019729A1 (fr) 1997-06-05

Family

ID=24250532

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CA1996/000778 Ceased WO1997019729A1 (fr) 1995-11-28 1996-11-27 Procede et appareil d'epuration d'acide residuel

Country Status (1)

Country Link
WO (1) WO1997019729A1 (fr)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB793192A (en) * 1955-01-14 1958-04-09 Bergwerksverband Gmbh Improvements in or relating to the oxidative treatment of organic substances
US4042502A (en) * 1973-05-10 1977-08-16 Veb Jenapharm Jena Detoxification of cyanides and cyanide-containing solutions
SU800127A1 (ru) * 1974-10-23 1981-01-30 Предприятие П/Я Г-4807 Способ очистки серной кислотыОТ ОРгАНичЕСКиХ пРиМЕСЕй
DE3015957A1 (de) * 1980-04-25 1981-11-05 Hoechst Ag, 6000 Frankfurt Verfahren und vorrichtung zur konzentrierung und reinigung von abfallschwefelsaeure
FR2482763A1 (fr) * 1980-05-16 1981-11-20 Doryokuro Kakunenryo Procede de jonctionnement stabilise d'une cuve de digestion acide en tantale
JPS57163899A (en) * 1981-02-28 1982-10-08 Nippon Genshiryoku Hatsuden Method of treating radioactive organic waste
DE4230099A1 (de) * 1992-09-09 1994-03-10 Bayer Ag Verfahren zum Regenerieren gebrauchter Schwefelsäure

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB793192A (en) * 1955-01-14 1958-04-09 Bergwerksverband Gmbh Improvements in or relating to the oxidative treatment of organic substances
US4042502A (en) * 1973-05-10 1977-08-16 Veb Jenapharm Jena Detoxification of cyanides and cyanide-containing solutions
SU800127A1 (ru) * 1974-10-23 1981-01-30 Предприятие П/Я Г-4807 Способ очистки серной кислотыОТ ОРгАНичЕСКиХ пРиМЕСЕй
DE3015957A1 (de) * 1980-04-25 1981-11-05 Hoechst Ag, 6000 Frankfurt Verfahren und vorrichtung zur konzentrierung und reinigung von abfallschwefelsaeure
FR2482763A1 (fr) * 1980-05-16 1981-11-20 Doryokuro Kakunenryo Procede de jonctionnement stabilise d'une cuve de digestion acide en tantale
JPS57163899A (en) * 1981-02-28 1982-10-08 Nippon Genshiryoku Hatsuden Method of treating radioactive organic waste
DE4230099A1 (de) * 1992-09-09 1994-03-10 Bayer Ag Verfahren zum Regenerieren gebrauchter Schwefelsäure

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 8143, Derwent World Patents Index; Class A41, AN 81-79065D, XP002025484 *
DATABASE WPI Section Ch Week 8246, Derwent World Patents Index; Class K07, AN 82-98438E, XP002025483 *

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