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
  • A62D3/37—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by reduction, e.g. hydrogenation
• • 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
  • A62D3/34—Dehalogenation using reactive chemical agents able to degrade
• • 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
  • A62D2101/04—Pesticides, e.g. insecticides, herbicides, fungicides or nematocides
• • 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
  • A62D2101/22—Organic substances containing halogen

Definitions

• the present invention relates to a method for the disposal of halogenated and non-halogenated waste materials.
• halogenated hydrocarbons such as those present in carbon tetrachloride, chloroform, methylene chloride, tetra- and trichlorethylene, tetrachloroethane, PCB etc. but also in PVC or polyvinylidene chloride, are a more or less problematic toxic or hazardous waste after use Disposal applies.
• halogenated compounds in particular polyhalogenated substances such as PCBs or TCDD / TCDF (dioxins / furans) cannot be easily recycled and must be disposed of in an environmentally friendly manner.
• US-A-4,435,379 describes a process for the decomposition of chlorinated hydrocarbons with metal oxides with the aim of all carbon atoms in To transfer carbon oxide. It is important to provide elemental chlorine for the conversion of hydrogen groups into HCl. The total ratio of chlorine to hydrogen groups must be at least 1: 1 in order to be able to produce metal chloride.
• US-A-4,587,116 describes a similar process in which nitrogenous waste can also be disposed of.
• the heating also takes place from the outside and not from the inside.
• EP 0 306 540 describes a process for the production of energy from substituted hydrocarbons, such as those present as CCl 4 , CHCl 3 , C 2 H 2 Cl 4 , PCB, PVC, polyvinylidene chloride etc. in pure or bound form.
• the waste material is thermally decomposed in an inductively heatable reactor in the presence of a metal oxide which is difficult to smelt and an electrically conductive material, for example electrode coke or electrographite, and in contact with water vapor at temperatures between 800 and 1,100 ° C.
• a proportion of the metal oxide that corresponds to the chlorine content of the waste materials is converted into volatile metal chloride.
• a portion of the released carbon is converted into carbon monoxide and the portion of the carbon that does not react with the metal oxide is converted into water gas (CO + H 2 ) with the aid of a stoichiometric amount of water vapor.
• the object of the present invention is to develop a method which makes it possible to dispose of various halogenated and non-halogenated carbon-containing waste materials in an environmentally friendly manner.
• This object is achieved according to the invention by a process for the disposal of halogenated non-halogenated carbon-containing waste materials, in which the halogenated and non-halogenated carbon-containing waste materials are reacted with metal oxide-containing products with the exclusion of oxygen at temperatures of 800 ° C. to 1100 ° C. It is particularly noteworthy that carbon dioxide is added in the process.
• the process described here is used for the environmentally neutral recycling of halogenated and non-halogenated waste materials.
• the volume of the waste used is largely reduced, so that as few residues as possible remain and the largest possible amount of metals / metal compounds is obtained.
• the aim is to achieve the most positive energy balance possible during implementation.
• the reactor can also be charged with carbon in the form of graphite and / or coal.
• a halogenatable product containing metal oxide is preferably used as the metal oxide-containing starting material.
• products which contain CaO, TiO 2 , SiO 2 , Al 2 O 3 and / or Fe 2 O 3 or a mixture thereof are used as halogenatable metal oxide-containing reactants.
• Various metal oxide-containing waste materials such as silicon-containing residues from the metalworking industry, filter dusts, fly ash, flying sands, pile of heaps, electroplating sludge, slag, slate residues etc. can also serve as reaction partners.
• Simple quartz sand which consists of approximately 98% silicon dioxide (SiO 2 ), is the simplest possible material that can be used for the implementation.
• halogenatable metal oxides CaO, SiO 2 , TiO 2 , Al 2 O 3 , Fe 2 O 3 etc.
• solvents such as: carbon tetrachloride, chloroform, methylene chloride, tetra- and trichlorethylene, tetrachloroethane, coolants or refrigerants, PCB, pesticides, fungicides and herbicides, halogenated plastics such as e.g. Use PVC.
• a proportion of the metal oxide that corresponds to the chlorine content of the waste materials is converted into metal chloride by the above-mentioned process.
• Ecologically and economically valuable metal chlorides are formed, with silicon and titanium tetrachloride (SiCl 4 , TiCl 4 ) being particularly preferred products.
• Used oils, lubricants, greases, varnishes, paints, tars, waxes, plastics, coolants and solvents, brake fluid or similar non-halogenated substances and materials must be disposed of.
• thermodynamically preferred reaction or reaction products formed under these process parameters are primarily gaseous hydrogen (H 2 ) in addition to lower percentages of methane (CH 4 ).
• the reactor can be brought to the necessary operating temperatures either by using electrical heating elements (eg heating half-shells) or by using induction heating.
• the temperatures required for the implementation are in the range of 800 ° C to 1100 ° C.
• the reaction itself takes place with the exclusion of oxygen.
• Carbon dioxide (CO 2 ) is used as the fluidizing gas.
• the halogenated compounds are broken down into their simplest components by the high temperatures, in the case of chlorinated hydrocarbons hydrogen chloride, hydrogen, alkanes and chlorine gas are formed.
• the chlorine gas and the hydrogen chloride serve as chlorinating agents for the metal oxide-containing products or wastes. Products of this chlorination reaction are the thermodynamically preferred metal chlorides.
• the carbon dioxide (CO 2 ) used as fluidizing gas is completely converted to carbon monoxide (CO) by reaction with the carbon of the decomposed hydrocarbons and by an additional bed of carbon or graphite in the head of the reactor.
• All halogenated metal compounds produced are initially in gaseous form. Depending on the starting material, solid cooling, i.e. crystalline metal compounds can be obtained, or liquid metal compounds by condensation at low temperatures.
• the purity of these compounds is 96% and can e.g. by fractional distillation, or rectification.
• the reactor 5 is heated by means of a reactor heater 6 to a temperature between 800 ° C and 1100 ° C, so that there is a reaction between the halogenated waste and the metal oxide-containing substances in the reactor.
• the products formed are separated in a solid separator 7 and the solid metal chlorides formed, in particular AlCl 3 and FeCl 3 , are discharged via a line 8.
• the remaining gases are cleaned by an activated carbon filter 9 and then compressed by a blower 10.
• the gases are then cooled in a cooling container 12, which has a coolant inlet 11 and a coolant outlet 13, so that the remaining metal chlorides are eliminated. It is mainly SiCl 4 .
• the gases are then fed to a condenser 15 and subjected to an alkaline gas scrubbing in a gas scrubbing column 16.
• the column 16 has a circulation pump 17 for the washing liquid.
• the remaining synthesis gas, a mixture of CO and H 2 is discharged via line 18 in the upper part of the gas scrubbing column 16.
• the slate waste is crushed using a jaw crusher. Average grain sizes in the range of 3 - 8 mm are advantageous.
• the ground shale can be introduced into the reactor by spraying with the fluidizing gas carbon dioxide (CO 2 ).
• CO 2 fluidizing gas
• Another supply of fluidizing gas is used to create and maintain the fluidized bed.
• An amount of about 20-27 m 3 CO 2 is supplied as fluidizing gas per hour.
• the temperature of the fluidizing gas is advantageously brought to about 500 ° C.
• Perchlorethylene C 2 Cl 4 , PER
• the PER is introduced as a kind of aerosol from a partial fluidization gas stream directly into the reaction zone of the reactor. There the PER is broken down into its components. The difference between PER and others Solvents is that there are no hydrogen atoms in the molecule. As a result, the formation of hydrochloric acid (HCI) is not possible.
• chlorine gas (Cl 2 ) is formed, which is an excellent chlorinating agent.
• the chlorine gas therefore reacts with the metal oxides of the slate in the fluidized bed to form metal chlorides (generally Me x Cl y ).
• Aluminum chloride (AlCl 3 ), ferric chloride (FeCl 3 ) and silicon tetrachloride (SiCl 4 ) can be formed in this way.
• the elemental carbon (C) obtained during the thermal decomposition of the chlorinated hydrocarbons reacts either with the fluidizing gas (CO 2 ) or with the bound oxygen of the metal oxides to form carbon monoxide.
• Reaction equation 3 describes the chlorination of silicon dioxide with the formation of silicon tetrachloride and carbon monoxide. SiO 2 + C 2 Cl 4 ⁇ SiCl 4 + 2CO Reaction equation 3
• reaction equation 4 generally applies to the disposal of PER with slate: SiO 2 + 2 Al 2 O 3 + 2 feet 2 O 3 + 7 C. 2 Cl 4 ⁇ SiCl 4 + 4 AlCl 3 + 4 FeCl 3 + 14 CO Reaction equation 4
• reaction equation 4 It is clear from reaction equation 4 that various metal chlorides are formed in addition to carbon monoxide. All substances are initially gaseous at temperatures around 1000 ° C. Immediately after the reactor, the gases cool down very quickly to around 800 ° C through the ambient air.
• Separation devices such as cyclones or activated carbon filters make it possible to separate and retain dusty or crystalline metal chlorides, but mainly aluminum chloride and iron chloride, from the process gas stream. Supported by a blower, the gas stream is drawn through the filters. This has the consequence that a slight negative pressure already on Reactor outlet is to be noted, which is in the range of about 0.01-0.05 bar under normal pressure.
• the residual gases contain gaseous silicon tetrachloride and carbon monoxide. Since the silicon tetrachloride changes to the solid state at temperatures below - 68 ° C, the process gas must be cooled down to temperatures of around - 50 ° C. This is done by pre-cooling with liquid nitrogen and post-cooling using a cooling mixture in a condensation column.
• the cold mixture used is an acetone / dry ice mixture, which can generate temperatures down to a maximum of - 86 ° C.
• the gaseous silicon tetrachloride is reflected in the above Temperatures in the condenser and is collected in a storage container.
• the degree of purity of the condensed silicon tetrachloride is approximately 96%. Any foreign substances that may be present can be removed by a subsequent fractional distillation.
• the result of the purification by distillation would be a silicon tetrachloride solution with a degree of purity of approx. 99%.
• the process gas is fed to an alkaline gas wash with a 10% potassium hydroxide solution according to the countercurrent principle.
• the gas purified in this way only contains carbon monoxide.
• the process engineering design of the plant corresponds to the design that was also used for the disposal of perchlorethylene (PER).
• PER perchlorethylene
• AlCl 3 , FeCl 3 The process engineering separation of aluminum and iron chloride (AlCl 3 , FeCl 3 ) takes place on the one hand by centrifugal force separation in a cyclone and on the other hand by separation in special filters.
• the silicon tetrachloride is separated off in the manner already described.
• reaction equation 8 it can be seen from reaction equation 8 that in addition to the metal chlorides, a synthesis gas consisting of carbon monoxide and hydrogen is formed.
• the ratio between hydrogen and carbon monoxide is 1: 2.3.
• Example of use 3 Disposal of hydrocarbon (KW) or halogenated hydrocarbon (HKW) waste in the presence of galium oxide
• the various feed materials such as Oils, greases, PCBs, CFCs, solvents or the like are fed through a metering device, e.g. an eccentric screw pump, conveyed into the reaction zone.
• a metering device e.g. an eccentric screw pump
• the residence time of the feed materials or that of the cleavage products formed is determined by the height of the reaction zone.
• halogenated feed materials in particular chlorinated materials
• a reaction occurs between the calcium oxide and the halogen atoms of the feed materials.
• reaction equation 1 takes into account all essential products that are formed during the disposal or recycling of a halogenated hydrocarbon. The individual products were calculated thermodynamically and verified experimentally.
• carbon is also discharged from the reactor in the form of fine soot particles.
• the separation of the other gaseous components hydrogen and methane, or hydrogen and carbon monoxide (CO), is carried out by gravity separators, e.g. a high performance cyclone.
• the gases cleaned in this way can still be passed through activated carbon filters. If there are still foreign components in the process gas, they can be removed either by targeted condensation or by gas scrubbing.

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• 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)
• Health & Medical Sciences (AREA)
• Processing Of Solid Wastes (AREA)
• Fire-Extinguishing Compositions (AREA)
• Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Silicon Compounds (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)

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• 1997
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• 1998
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  • 1998-07-20 WO PCT/EP1998/004508 patent/WO1999004861A1/de active IP Right Grant
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