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
  • B01D53/02—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 by adsorption, e.g. preparative gas chromatography
• • 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
  • B01D53/02—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 by adsorption, e.g. preparative gas chromatography
  • B01D53/04—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 by adsorption, e.g. preparative gas chromatography with stationary adsorbents
• • 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
  • B01D53/88—Handling or mounting catalysts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/061—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof containing metallic elements added to the zeolite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/106—Silica or silicates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/106—Silica or silicates
  • B01D2253/108—Zeolites
  • B01D2253/1085—Zeolites characterized by a silicon-aluminium ratio
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/30—Sulfur compounds
  • B01D2257/302—Sulfur oxides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/40—Nitrogen compounds
  • B01D2257/404—Nitrogen oxides other than dinitrogen oxide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/50—Carbon oxides
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
  • Y02C20/00—Capture or disposal of greenhouse gases
  • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

• THIS INVENTION relates to the use of alumino-silicate materials for the catalytic conversion and/or adsorption of gas mixtures, such as those containing nitrous oxide, nitric oxide and nitrogen dioxide (generically termed "NOx") and/or other pollutant gases including, but not limited to, SOx, C0 2 , CO, dioxins and polycyclic aromatic hydrocarbons (generically termed "PAH"s) and combinations thereof.
• the invention also relates to any of the aforementioned gas mixtures or gases which also contain particulates.
• alumino-silicate materials function as a catalyst for the catalytic conversion of these gases or gas mixtures or adsorb these gases or gas mixtures. These chemical processes may generally occur at elevated temperatures between 200°C and 850°C and over a wide range of gas flow and gas composition conditions.
• This latter catalyst system typically operates at temperatures in the range 300-400°C and exhibits good resistance to poisoning in the presence of SOx in the exhaust gas.
• the catalyst is presented as either a plate-type or honeycomb monolith operating in the parallel flow mode which serves to minimize plugging of the catalyst bed by particulates
• the second process uses zeolite materials to catalyze the aforementioned reaction between ammonia and nitric oxide, although in this instance the optimum operating temperature is notably higher (ca. 500°C).
• zeolite materials e.g. ZSM5
• Famos et al. U.S. Patent 545138
• cerium-exchanged mordenite zeolites have been described by van den Bleek et al., (Netherlands Patent Application No. NL 9302288).
• Cu-ZSM5 catalysts have been shown by Sullivan etal., 1996, (App. Catalysis B: Environmental 7415- 417), to exhibit comparable activity to conventional vanadia/titania SCR catalysts and Komatsu et al., 1995, (J. Phys. Chem. 99 13053), deduced from infrared spectroscopy measurements that nitrate species formed on the zeolite surface subsequently reacted with ammonia to produce product nitrogen.
• nitrous oxide N 2 O
• anionic clay minerals such as hydrotalcites, sjogrenites and pyroaurites containing activator species such as alkali metals or alkaline earth metals (Farris et al., U.S. Patent No. 5472677).
• Another application uses the loading of lanthanides and/or transition metals on the kaolin derivative in reduction-oxidation catalyzed reactions such as the dehydrogenation of methanol to methyl formate.
• This specification also included specific examples directed to use of the kaolin derivative wherein the alkali metal cation was exchanged with copper in relation to dehydrogenation of methanol to methyl formate at elevated temperature and dehydrogenation of ethanol to acetaldehyde at elevated temperature.
• the reference to the catalysis of methanol vapour and ethanol vapour is the only example of use of a metal exchanged kaolin derivative when used for catalysis.
• alumino-silicate materials as described herein, inclusive of kaolin amorphous derivatives as described in International Publication No. WO95/00441 can be utilized in relation to conversion, via selective catalytic reduction and/or direct decomposition of NOx gases and other toxic gases such as CO, C0 2 , SOx, dioxins and PAHs to environmentally benign product(s).
• the mechanism for such catalysis appears to involve the electronic configuration of the exchangeable metal ion when held by the alumino-silicate derivative which appears to have a surprising effect on the overall activity of the catalyst.
• the alumino-silicate materials for use in the present invention have a primarily tetrahedrally co-ordinated aluminium and have a cation exchange capacity of at least 1 meq 100 g '1 in aqueous solution at room temperature.
• such materials have a CEC of above 100 meq 100 g "1 and more preferably have a CEC of between 160-900 meq 100 g "1 and most preferably have a CEC of between 350-450 meq 100 g "1 using methods of determination defined in previous disclosures (e.g. International Publication Nos. WO96/18576 and W096/18577).
• MAS 27 AI Magic Angle Spinning
• the alumino-silicate materials for use in the present invention also include an exchangeable cation which is an ammonium ion or alkali metal cation which may be partly or fully exchanged by a secondary metal selected from one of the following:- the alkaline earths Mg 2+ , Ca 2+ , Sr 2* and Ba 2+ , the transition metals Cr 3 ", Mn 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , Ag ⁇ the heavy metals Pb 2+ , Cd 2+ , Hg 2+ ; the lanthanides- Lai and NcP or the actinide U0 2 2+ .
• a secondary metal selected from one of the following:- the alkaline earths Mg 2+ , Ca 2+ , Sr 2* and Ba 2+ , the transition metals Cr 3 ", Mn 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , Ag ⁇ the heavy metal
• the alumino-silicate materials for use in the invention are amorphous in nature and thus cover kaolin amorphous derivatives or KADs as described in International Publication No. WO95/00441 or alumino-silicate derivatives (ASDs) as described in International Publication Nos. W096/18576 or W096/18577.
• KADs or ASDs may be prepared by reaction of a starting alumino-silicate with MOH and/or MX where M is alkali metal and X is halide.
• Such compounds may have a chemical composition of the general formula,
• M ammonium ion or alkali metal cation
• X is halide wherein M as NH 4 + , Na + , K + , Li + , Rb + or Cs may be exchanged by one of the secondary metals discussed above.
• the alkali metal alumino-silicate materials for use in the invention may comprise amorphous or poorly or partly crystalline alumino-silicates having a stuffed silica polymorph-related structure which is produced by reacting a starting alumino-silicate or a combination of aluminium oxide-containing and silicon-oxide containing compounds with an alkali oxide or alkali hydroxide containing reagent.
• stuffed silica polymorphs include kalsilite, camegieite, eucryptite or nepheline. These polymorphs are stuffed derivatives of the tridymite, cristobalite or quartz structures. Such materials are described in International Publication No. WO96/12678, which disclosure is included herein by reference.
• the alumino-silicate materials for use in the invention also include modified kaolins which may be prepared from a kaolin group mineral which includes expansion and contraction of layers of the kaolin group mineral wherein these layers comprise one Si-tetrahedral sheet and one Al- octahedral sheet.
• modified kaolins and their cation-exchangeable alumino-silicate derivatives are described in International Publication No. WO97/15427, which disclosure is included herein by reference.
• the alumino-silicate materials as described above may be utilized for the stable catalytic transformation of NO x , to N 2 and H 2 O in the presence of hydrocarbons to achieve selective catalytic reduction (SCR).
• SCR selective catalytic reduction
• These materials can be produced with a variety of pore sizes and surface structures and may contain significant levels of surface-bonded metals such as copper, iron, cerium or cobalt which are active for conversion of NO x .
• the cation- exchangeable material as described in International Publication Nos. WO95/00441 , WO96/18576, W096/18577 and W096/12678 may also effect this catalytic transformation albeit at lower levels of conversion.
• any form of the abovementioned alumino-silicate materials will effect conversion, if the gas stream contains amounts of metal ions which are active for conversion of NOx.
• the metal ions from the gas stream are adsorbed onto the alumino-silicate substrate wherein similar selective catalytic reduction of NOx in the presence of hydrocarbons occurs.
• the exchangeability of metal ions, as well as high surface area values for the metal-loaded substrate are desirable attributes of the alumino-silicate materials with regard to subsequent catalysis performance.
• TABLE 1 illustrates values for the cation exchange capacity (CEC) and surface area for conventional alumino- silicate materials such as ZSM5, kaolin clay and pillared clays compared with these values for the alumino-silicate materials specified in International Publication Nos. WO95/00441 , WO96/18576 and W096/18577.
• CEC cation exchange capacity
• the metal-exchanged ion - that is, the electronic states or valences - induced by the cation-exchange process with the alumino-silicate material which influences the catalytic behaviour of these materials with respect to conversion of noxious gases such as NOx, dioxins and/or PAH or combinations, thereof.
• the nature of these electronic states are described herein for typical samples listed in TABLE 2 using spectroscopic and adsorption/desorption methods well-known to those skilled in the art. For specific data sets, a comparison is made with the electronic states for equivalent metal-exchanged zeolite species.
• these materials may also react with NOx in the presence of toxic gases such as SOx without apparent degradation of catalytic performance due to the presence of SOx.
• these materials may also react with organic gaseous compounds such as dioxins and polycyclic aromatic hydrocarbons (PAH).
• organic gaseous compounds such as dioxins and polycyclic aromatic hydrocarbons (PAH).
• Subtle variations in bulk properties within and between these various samples listed in TABLE 2 can be achieved by manipulation of the product or intermediate compound using conventional techniques well-known to those skilled in the art.
• the extent of cation exchange achieved with the secondary process using copper nitrate solution listed in TABLE 2 may be increased or decreased substantially by variation of the molarity of the copper nitrate solution and/or the kinetics of the exchange reaction.
• other metal-loaded solutions such as cobalt acetate and copper acetate (or combinations thereof) may be used to achieve the appropriate level of copper and/or cobalt exchanged alumino-silicate material.
• These metal-exchanged alumino-silicate materials are suitable materials for the catalytic conversion of gases.
• XPS X-ray photoelectron spectroscopy
• a common property identified by those skilled in the art of catalysis materials relates to the chemical composition of the substrate material which hosts the active sites for catalysis or decomposition reactions.
• the composition of these materials can be described in terms of bulk or surface chemistry.
• the general bulk chemical compositions of these new materials have been described in the previous disclosures referred to above. These bulk compositions were determined by well-known techniques, such as electron microprobe analysis and wet chemical analysis, using atomic absorption spectroscopy and/or inductively coupled plasma spectroscopy.
• the Si/AI ratio is in the range 1.0 to 1.5 for all samples which demonstrate suitable catalytic activity to NOx or which directly decompose NOx at suitable temperatures.
• zeolites nominated for exhaust catalysis of NOx usually employ Si/AI ratios of >15 (Yoshimura etal., Jpn, Kokai Tokkyo Koho JP08, 108,043 (96,108.043).
• An example of the ratios for Cu-ZSM5 is also listed in TABLE 5.
• the novel materials detailed in this disclosure have very low Si/AI ratios which are not easily obtainable by conventional zeolite preparation methods.
• the above characteristics of the metal-exchanged alumino-silicate materials are typical of those required for the effective chemical conversion (via catalysis), decomposition or adsorption of toxic inorganic gases such as NOx, and toxic organic gases such as dioxins and polycyclic aromatic hydrocarbons.
• alumino-silicate materials are amenable to fabrication into specific shapes or monoliths using conventional ceramics forming techniques. However, most trials of this material to date have utilized either a powdered or a pelleted form and are pretreated by high temperature calcination in flowing air at 500°C for two hours.
• the process of the invention has relevance to the reduction of NOx in the presence of organic reductants at a temperature of 200-650°C wherein the NOx is adsorbed by the alumino-silicate material.
• the organic reductants include hydrocarbons inclusive of alkanes, alkenes, aromatics inclusive of benzene and polycyclic hydrocarbons as well as oxygen- containing organic compounds inclusive of alcohols and aldehydes.
• the temperature of 200-650°C is dependent upon the choice of the organic reductant. This process is applicable in relation to treatment of exhaust gases from furnaces, incinerators or vehicle exhausts.
• the process of the reaction is also applicable to the reduction of NOx using nitrogen containing reductants inclusive of ammonia and urea.
• a temperature of between 200-650°C is applicable to the use of ammonia and a temperature of 350-500°C is applicable to the use of urea.
• the process of the invention is also applicable in the direct decomposition of NOx to nitrogen at a temperature of 200-850°C.
• the alumino-silicate material for this specific application contains Fe, Cu or Ag or other metals as described in Example 8.
• ASDs which are doped with or which contain basic oxides inclusive of CaO and MgO or other alkaline earth metal oxides as well as transition metal oxides inclusive of CuO, ZnO or iron oxides. This may be accomplished by reacting the alumino-silicate material (hereinafter alumino-silicate derivative or ASD) with a soluble salt of the relevant oxide such as the nitrate or the halide followed by drying and heating.
• the gas containing C0 2 or CO 2 perse is passed through the ASD so that the CO 2 is adsorbed by the ASD.
• a suitable temperature is between room temperature and 300°C.
• a similar process as described above in relation to C0 2 may also apply to processing of SOx inclusive of SO 2 wherein the SOx is passed through the ASD and is adsorbed by the ASD or reduced to sulphur. Temperatures for adsorption of SO 2 are usually between 0-500°C and more suitably between room temperature and 150°C.
• the ASD may be doped with basic metal oxides or transition metal oxides as described above.
• the process of the invention may also be applied to oxidation of SO 2 to S0 3 wherein an ASD containing Pt, Pd, Ag, Cu, Co, Mn or Cr is utilized at a temperature of 150-650°C.
• a similar process is used for oxidation of CO to C0 2 .
• the ASD may contain Pt,
• Dioxins may be converted to H 2 0, HCI and C0 2 .
• An example in relation to treatment with dioxins is shown in Example 9.
• suitable gases which are subject to the process of the invention include anthracene, fluorene, pyrene, perylene, chrysene and naphthacene.
• the conversion rate or percentage removal from a gas stream being treated by the catalysts of the invention depends on the temperature which is utilized and the higher the temperature utilized will result in the more efficient removal of gas pollutant from the gas stream.
• a conversion or removal rate of around 30-40% may apply in relation to temperatures of about 200-250°C. This conversion rate may increase to 60% in the case of 350°C.
• temperatures of 450-500°C may result in greater than 80% conversion and this may also apply in relation to diesels wherein a temperature of 200-600°C may be utilized.
• the conversion data in FIG. 2 for these experiments show that the copper-exchanged catalyst Cu-KAD3-1 does indeed exhibit excellent potential for direct NO x decomposition since 100% NO x conversion is achieved at 550°C and at flowrates approaching those of commercial conditions.
• the conditions employed during these preliminary trials of the copper-exchanged catalyst material are substantially more severe than those used in previous studies of Cu-ZSM5 (N. Yoshida and Y. Kato, 1996, supra).
• a comparison of the data presented by Iwamoto et al. (1986, supra) and calculations for these preliminary trials, reveal that the copper-exchanged catalyst material is at least an order of magnitude more active than Cu-ZSM5 under these same conditions.
• Co-KAD was prepared by contacting K-KAD with a cobalt nitrate solution.
• An example of the superior adsorption properties of cobalt-exchanged KAD materials with respect to conventional cobalt-exchanged zeolites is provided by inspection of FTIR spectra which were recorded at ambient temperature following exposure of an OJ0 2 mixture to the catalyst surface.
• FIG. 4 gives a summary of these spectral data.
• a plug of the catalyst material (0 -5.0-5.5 mm by 60-70 mm long) is inserted in the centre of a 900 mm long quartz tube and held in place using quartz wool.
• the gas stream was directed through a parallel quartz tube containing quartz wool only.
• the reactor tubes were held in an 860 mm Lindberg furnace at a temperature of 500°C ( ⁇ 50°C) for all cases except sample K-KAD5-15. In the case of sample K-KAD5-15, the reaction was carried out at 400°C ( ⁇ 50°C). The gas stream was then conditioned for removal of particulates and moisture using a Perma Pure dryer. Concentrations of NO x were monitored using a 0-2000 ppm Analytical Developments Company Infrared NO x detector.
• Gases were drawn through the catalyst material at a rate of 1.0 to 1.2 litres per minute ⁇ gas hourly space velocity (GHSV) - 60,000 h '1 ⁇ . Sampling times for all gases ranged from 20 minutes to 30 minutes.
• GHSV gas hourly space velocity
• sample K-KAD3-8 shows a conversion efficiency less than 90% while all others are greater than 90%. Operation of these catalysts at different temperatures and with various combinations of hydrocarbons and/or water vapour will result in different levels of conversion efficiency. For example, as shown for sample K-KAD3-8, the comparative absence of hydrocarbons in the secondary chamber results in a lower reduction in NOx levels (conversion of - 11.5%) in the gas stream treated with this catalyst material. However, the relative absence of hydrocarbon in this case demonstrates that even at 500°C ( ⁇ 50°C) direct decomposition of NO x can occur with this catalyst material.
• a plug of the catalyst material ( ⁇ -5.0-5.5 mm by 60-70 mm long) is inserted in the centre of a 900 mm long quartz tube and held in place using quartz wool.
• the gas stream was directed through a parallel quartz tube containing quartz wool only.
• the reactor tubes were held in an 860 mm Lindberg furnace at a temperature of 500°C ( ⁇ 50°C) for all cases.
• the gas stream was then conditioned for removal of particulates and moisture using a Perma Pure dryer. Concentrations of NO x were monitored using a 0-2000 ppm Analytical Developments Company Infrared NO x detector. Gases were drawn through the catalyst material at a rate of 1.0 to 1.2 litres per minute ⁇ gas hourly space velocity (GHSV) - 60,000 IT 1 ⁇ . Sampling times for all gases were 20 minutes.
• GHSV gas hourly space velocity
• TABLE 9 presents raw and compiled data for the field trial of five Cu- and Co-based catalyst materials for the conversion of NOx from diesel exhaust.
• EXAMPLE 6 Selective Catalytic Reduction of NOx in diesel engine exhaust using propene or diesel fuel
• a KUBOTA GV1120 diesel engine in which the exhaust from the operating engine is coupled to a gas injection system. Additional hydrocarbon is subsequently added to the exhaust stream, either as a mixture of propene in nitrogen or as diesel fuel.
• This mixture is then contacted with an appropriate amount of catalyst situated within a reactor tube located in a heated furnace using a similar arrangement to that shown schematically in FIG. 6.
• the treated gases are then analyzed by both an FTIR gas cell and, after passage through a dehumidifier, by a dedicated infrared NOx analyzer.
• Catalysts were prepared by the following protocol. Firstly, K- KAD was converted to NH 4 + KAD and TiCI 4 were mixed together and then the TiCI 4 was hydrolyzed by the addition of aqueous ammonia. Finally, after drying the Ti-KAD at 120° and calcination to 500°C, the Ti-KAD was impregnated with appropriate amounts of aqueous iron nitrate, niobium chloride, tin chloride, ammonium metavanadate or ammonium metatungstate. Again, this material was calcined at 500°C before use in the micro-reactor shown in FIG. 10.
• Fe-KAD catalysts were prepared by exchanging K-KAD with an aqueous solution of either iron nitrate and/or iron and cerium nitrates. In order to enhance the concentration of iron and/or cerium exchanged the solution was was purged with nitrogen to remove dissolved oxygen.
• Different iron-KAD catalysts as described in FIG. 13 were prepared by varying the pH between 2 and 4. Results of the use of such catalysts in the direct decomposition of NOx is shown in FIG. 13. EXAMPLE 9 Reduction of dioxins from exhaust gas streams
• PCDDs Polychlorinated dibenzo-p-dioxins
• PCDFs polychlorinated dibenzofurans
• dioxins can be formed downstream of a combustion chamber as the gases are cooled via a process known as De Novo synthesis. This occurs in the temperature range 250-400°C by reactions between the products of incomplete combustion in the presence of a chlorine donor. Certain materials can act as catalysts in these reformation reactions. However, current research suggests that some materials may also transform dioxins and other organic micro-pollutants into non-toxic byproducts.
• interst are the NO x reduction catalysts, which have been reported in the literature as having the potential to reduce the concentration of dioxins and related micro-pollutants.
• the incinerator is of the two chamber design, consisting of a primary chamber for the combustion of solid waste and a secondary chamber/afterburner for the oxidation of combustible gases and particulate matter discharged from the primary chamber.
• the primary chamber is of a stationary hearth design utilizing a series of rams to slowly push the waste material through the incinerator for complete ash burn-down.
• the secondary chamber is capable of maintaining all emissions produced in the primary chamber at a temperature of 800- 900°C for a retention time of 0.3-0.5 seconds.
• the primary chamber operates under reducing (starved air) conditions. By starving the process of air, the volatile components of the waste are gasified. The combustible gases produced behave as a fuel and are mixed with air and completely oxidized in the secondary chamber.
• Natural gas is used as a supplementary fuel in both chambers.
• Exhaust gases exiting the secondary chamber enter an air- cooled heat exchanger, dropping the gas temperature to 200°C. This was designed to maximise dioxin formation through the De Novo process.
• the gases then enter a baghosue, where they are filtered prior to discharge through a stack.
• testing was conducted at a gas outlet space velocity (gas flow rate (mls/hr)/volume of catalyst (mis)) of 60,000 hr 1 .
• a plug of the KAD material was inserted into the centre of a quartz tube, and held in place using quartz wool.
• the gas stream was directed through a parallel quartz tube containing only quartz wool. Both catalysis and baseline studies were conducted simultaneously.
• the parallel quartz reactor tubes were held in an 860 mm long Lindberg furnace at a temperature of 450°C ( ⁇ 20°C). The temperature was regulated with a Eurotherm controller. For each test, the system was pre- conditioned for 60 minutes prior to sampling. The samples were then collected over a 60-90 minute period. Test Methods Dioxins
• PCDDs and PCDFs were performed using high resolution gas chromatography and low resolution mass spectrometry in accordance with USEPA Method 8280.
• This method provides data on all toxic 2,3,7,8-chlorinated PCDDs and PCDFs as well as totals of non-2,3,7,8- chlorinated PCDDs and PCDFs for each homologue group (tetra to octa).
• the total toxic equivalent (l-TEQ) for each congener was calculated using NATO (international) toxic equivalency factors (l-TEFs).
• the sampling/experimental apparatus is depicted in FIG. 15.
• Nitrogen oxides were monitored in accordance with Georgia EPA Standard Analytical Procedure B12 - "Total Nitrogen Oxides", using a Testo 350 series NO/N0 2 /NOx analyzer. This was calibrated using NATA certified nitric oxide (NO) span gas, and zeroed with instrument grade nitrogen.
• Oxygen concentration was monitored in accordance with Victoria EPA Standard Analytical Procedure B10 - "Oxygen (Instrumental)", using a Testo 350 series analyzer. This was calibrated using ambient air, and zeroed with instrument grade nitrogen.
• the estimated accuracy is ⁇ 5%.
• the dioxn and NOx results are summarized in Tables 12 and 13.
• the comprehensive dioxin results are given in Tables 14-27. While the above Examples refer specifically to the use of the alumino-silicate materials as catalysts in relation to NOx and dioxins, it is to be noted the alumino-silicate materials and their catalytic action on NOx and dioxins are exemplary of heterogeneous catalysis (as defined, for example, in Chemistry, Fifth Edition by Raymond Chang, published by McGraw-Hill Inc. in 1994). Such catalysis shows the use of a solid catalyst in a gaseous reaction system whereby an oxidation reaction occurs with dioxins and a reduction reaction occurs with NOx.
• alumino-silicate materials of the invention will catalyze SOx as described above, CO or CO 2 as described above and PAHs.
• Example 9 may also apply to the use of the alumino-silicate materials of the invention to PAHs as similar conditions apply.
• Particle size of catalyst 10-20 mesh(0.84-1.68 mm)
• Sm 3 gas volume in dry cubic metres at 0°C, 101.3 kPa and 11 % 0 2 .
• Nm 3 gas volume in dry cubic metres at 0°C, 101.3 kPa and 7% 0 2 .
• FIG. 1 A first figure.
• FIG. 2 Comparison of NO x Decomposition on (a) Cu-ZSM5 (squares) and (b) Cu-
• CoKAD3-1 (b) CoKAD3-5, (c) CoKAD3-7, (d) CoKAD 1 / 2 -13, (e) CoKAD5-16 and (f) Co-ZSM5 (Si/AI ratio 40:1 ).
• FIG. 5 Schematic of incinerator configuration and sampling points for gases.
• FIG. 10 Micro-reactor system employed for de NOx studies.
• FIG. 15 Sampling/experimental apparatus comprising USEPA MM5 sampling train with integrated catalyst reactor.

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