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WO1993005868A1 - Filtre fibreux enduit pour le craquage catalytique - Google Patents

Filtre fibreux enduit pour le craquage catalytique Download PDF

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Publication number
WO1993005868A1
WO1993005868A1 PCT/US1992/008188 US9208188W WO9305868A1 WO 1993005868 A1 WO1993005868 A1 WO 1993005868A1 US 9208188 W US9208188 W US 9208188W WO 9305868 A1 WO9305868 A1 WO 9305868A1
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WO
WIPO (PCT)
Prior art keywords
catalyst
filter
hopcalite
air
carrier
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/US1992/008188
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English (en)
Inventor
James H. Cornwell
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North Carolina Center for Scientific Research Inc
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North Carolina Center for Scientific Research Inc
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Filing date
Publication date
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Publication of WO1993005868A1 publication Critical patent/WO1993005868A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0215—Coating
    • B01J37/0217—Pretreatment of the substrate before coating
    • 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
    • B01D53/864—Removing carbon monoxide or hydrocarbons
    • 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
    • B01D53/8668—Removing organic compounds not provided for in B01D53/8603 - B01D53/8665
    • 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
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
    • B01J35/58—Fabrics or filaments
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/34—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
    • B01J37/341—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation

Definitions

  • the present invention relates to filters for purifying indoor air.
  • HVAC heating ventilator
  • the air frequently contains, as well, a high level of particulates, e.g., mold spores, pollen, and dust, which serve as vehicles to carry microbiological contaminants, as the particulate filters commonly used in the HVAC systems are not very effective, and are often not properly maintained.
  • particulates e.g., mold spores, pollen, and dust
  • ASHRAE standards are normally used for comparison.
  • Ventilation problems are both used for evaluation purposes.
  • Some of the ventilation problems commonly encountered include an insufficient supply of fresh outdoor air, poor air distribution or mixing, which causes stratification, drafts, and pressure differentials between office space; temperature and humidity extremes or fluctuations, which sometimes are caused by poor air distribution or faulty thermostats; and air filtration problems caused by a faulty or nomaintenance ventilation systems.
  • the ventilation problems are created or compounded by certain energy conservation measures applied in the operation of the ventilation system. These including reducing or eliminating fresh outdoor air, reducing infiltration and exfiltration, lowering thermostat settings in winter, raising them in summer, elimination of humidification systems; and early afternoon shutdown with late morning start-up of emission systems.
  • Contamination generated by sources inside the office space is a major problem identified in 17% of the investigations.
  • Copier machines, computers, and other office equipment are often found to be a significant source of indoor contamination, ranging from ozone to polymers, acrolein, hydrogen cyanides, and materials from the inks and dyes used in the printing process. Examples of this type of problem include methyl alcohol from spirit duplicators, butyl methacrylate from signature machines, and ammonia and acetate from blueprint copiers.
  • Contaminants from inside or outside the office space, or the building fabric are essentially chemical contaminants. Many times odors are associated with some of these contaminants, which aid in source
  • outside air essentially caused by the re-entrainment of outside air. This is usually the result of improperly locating exhaust and intake vents and periodic changes in wind conditions.
  • Other outside contaminants include contaminants from construction or renovation projects such as asphalt, solvents, and dusts; also gasoline fumes invading the basement and/or sewage systems can sometimes be a
  • hypersensitivity pneumatosis This respiratory problem can be caused by bacteria, fungi, protozoa, and microbial products that may originate from ventilation system components.
  • Formaldehyde can offgas from ureaformaldehyde, foam insulation, particle board, and some glues and adhesives commonly used in construction. Building fabric problems encountered include dermatitis resulting from fibrous glass erosion in lined ventilating ducts, various organic solvents from glues and adhesives, and acetic acid, used as a curing agent in silicone caulking.
  • Tobacco smoke can irritate the respiratory system and, in allergic and asthmatic persons, often results in wheezing, coughing, eye and nasal irritation, sneezing, and other related sinus problems. People who wear contact lenses often complain of burning, itching, and tearing eyes from cigarette smoke.
  • the ASHRAE ventilation guidelines for smoking areas recognized the need to provide additional
  • filters that may be used in HVAC recirculation systems to remove particulate matter from polluted air streams. It would be desirable to remove harmful gaseous pollutants as well in indoor air treatment and other applications. It would also be desirable to provide a system for removal of such gaseous pollutants that operates at or near room temperature. Further, it would be desirable to provide a filters which could be used in a room or building air recirculation system to remove both harmful gaseous pollutants and particulates.
  • Catalytic converters used in automobiles employ catalysts of noble metals for conversion of hydrocarbons, carbon monoxide, and nitrous oxide.
  • Such catalysts are relatively high in cost, and moreover have a relatively high light off temperature, and thus require that the passing gas stream be maintained at a relatively high temperature. Aside from the cost of the catalyst
  • hopcalite which is a copper/manganese compound used in gas masks for converting carbon monoxide into carbon dioxide (CO 2 ).
  • CO 2 carbon dioxide
  • Conventional hopcalite is moisture sensitive, and the moisture (humidity) normally present in indoor air would eventually deactivate the catalytic properties of the material. This renders the material generally unsuitable for certain types of applications, such as HVAC systems.
  • Hopcalite is sold in granular pellets for use in a packed bed form and is not generally suitable for use as a filter coating.
  • conventional hopcalite is not suitable for wash coat formulations, in that its catalytic properties are deactivated when mixed in a slurry. This further limits its applications.
  • the present invention relates to filters for the treatment of polluted indoor air, in particular, for removing particulate matter and gaseous substances such as carbon monoxide and ozone at room temperature.
  • a preferred catalytic filter according to the invention has the ability to bring about ambient temperature oxidation catalysis for the following hydrocarbon groups or
  • hydrocarbons and halogenated hydrocarbons.
  • a filter according to the invention is constituted preferably by a fibrous filter material and is impregnated with a catalyst compound of the type composed of at least two mechanically mixed elements forming active catalyst sites at the boundaries of such elements.
  • the catalyst material has been surface modified by irradiation at an energy level sufficient to cause molecular dispersion of at least one of the elements and thereby increase the number of active sites.
  • the filter preferably comprises a non-woven polyester material wash coated with the catalyst
  • the preferred catalyst compound comprises a surface modified hopcalite.
  • the catalyst-coated filter may be a fibrous filter material, e.g. non-woven polyester, or a ceramic filter or metal substrate, which is wash coated with the catalyst.
  • the surface modified catalyst e.g., hopcalite
  • Apparatus according to the invention provides catalytic oxidation of hydrocarbons, carbon monoxide, and other harmful compounds, at room temperature. It
  • a filter material according to the invention is preferably formed by grinding the catalyst to a
  • formulations to the surface of a non-woven polyester carrier.
  • Various methods can be used to apply the formulation, such as immersion and spraying.
  • surface modified catalyst may be applied by impregnating the carrier with a binder containing a catalyst dispersion.
  • Fig. 1 is a schematic view of an apparatus which utilizes filters according to the invention.
  • Fig. 2 is a schematic view of a modified apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • Catalyst-coated filters according to the present invention will be described in relation to a preferred application of the filters in an indoor air treatment apparatus.
  • an air cleaning system includes a housing 10 with inlet vents 12 and a blower 14 having an outlet 16 for discharging air.
  • An interior duct passage 18 connects the inlet vents 12 and blower 14.
  • An ozone generator 20 is disposed in the path of the incoming air, immediately downstream of the inlet vent 12, with a pair of diffusion plates 21, 22 disposed on either side of the generator.
  • ozone generator may be in the form of a glass tube surrounded by aluminum scrim.
  • a capacitance field of sufficient strength, e.g., 5000 volts, is established between the glass and aluminum, to set up a continuously discharging capacitance field (without corona .discharge).
  • Ozone generators as described above, or optionally also using mercury, are well known and need not be described further here.
  • the diffusion plates 21, 22 act to create turbulence in the passing air stream, to enhance the mixing of ozone with the polluted air.
  • Each plate is provided with a plurality of holes, the number and size of which will depend upon the flow rate and acceptable pressure-drop.
  • the diffusion plate 21, upstream of the ozone generator 20, contains larger holes than the downstream plate 22.
  • plate 21 may be given holes of 1 ⁇ 2 inch, whereas plate 22 may be given holes of 1 ⁇ 4 inch diameter.
  • Filter 24 is a bio-mass collector, for example a 400 cells per inch expanded ceramic foam cordierite of a known type.
  • the known cordierite is preferably etched with ascetic acid to enhance its absorption capability.
  • Filter 26 is preferably a non-woven polyester fibrous filter (45% ASHRAE filter) which is surface coated with a combination of hopcalite (copper
  • Filter 28 is
  • Filter 30 is preferably also a non- woven polyester filter material (65% ASHRAE filter), which is surface coated with zeolite.
  • Filter 32 is a mechanical pre-filter, which may be of any known suitable type, for screening larger particles.
  • filter 34 is preferably a scrubber filter, e.g., a HEPA filter, for removing fine airborne particulates.
  • the filter materials in elements 24 - 34 are carried in cartridges or other such frames, which slide into receptacles in the apparatus housing, so that they can periodically be removed and replaced.
  • the respective filter cartridges and the receptacles be designed so that a respective cartridge is inserted in the proper
  • air is drawn into the inlet vent 12 by blower 14.
  • Hydrocarbons are removed in a two step process.
  • the air is brought into contact with ozone generated by the ozone generator 20.
  • Ozone is generated at a sufficient rate to set up a spontaneous titrated oxidation reduction reaction.
  • the allotropic oxygen generator continuously produces 4.187 grams per hour of O 3 .
  • Diffuser 21 acts to create sufficient turbulence to ensure that the oxygen is evenly mixed in the air stream.
  • hydrocarbons are removed in a two step process.
  • the airstream then enters the bio-mass
  • collector 24 containing a highly amorphous surface, which collects the bio-mass residue of the destroyed microbes.
  • filter 26 which contains a catalyst destructive to ozone (e.g., surface modified hopcalite and zeolite), thus eliminating it.
  • Filter 26 also acts to convert carbon monoxide to carbon dioxide.
  • the gas phase oxidator is generated by generator 20 in sufficient quantities to oxidize and reduce formaldehyde and ammonia catalytically. However, following this step any unreacted O 3 reduction reactant is removed in a second catalytic reaction in filter 26, through the action of the surface modified hopcalite, which is marketed by the assignee of the present
  • the gas phase oxidator removes ammonia in a similar manner, as explained by the following:
  • the ozone is used as a catalytic agent to oxidize and reduce the ammonia component and the modified hopcalite ML-114 is used as a catalyst to decompose the ozone.
  • the airstream now containing the by-products of the prior reactions, including O 2 , CO 2 and H 2 O, passes through filter 28, which is coated with calcium carbonate and thereby absorbs CO 2 and captures H 2 O.
  • the air passes through filter 30 containing zeolite, which acts to remove solvent vapors and water.
  • Filter 32 is a 65% ASHRAE particle filter, which removes larger particles from the airstream.
  • a HEPA filter 34 removes small particles, down to about 0.3 micron in size. The purified air is then exhausted through outlet 16.
  • the apparatus according to Fig. 2 is the same as that shown in Fig. 1, except that it contains a lead trapping filter 31 upstream of the HEPA filter 34.
  • the apparatus according to the present invention has the effect of acting on radon daughters, to accelerate its decay into lead. In certain applications, therefore, i.e., where the air to be treated contains any significant amount of radon,
  • filter 31 •elemental lead can be produced during the operation of the air treatment apparatus.
  • the purpose of filter 31 is to remove the lead from the air stream, and at the same time do so before it reaches the HEPA filter 34, since it would tend to clog such filter.
  • lithium nitrate and/or lithium hydroxide is added to the hopcalite.
  • lithium may be added to the hopcalite in an amount of approximately 15% prior to irradiation.
  • air flow, and particularly moist or damp air is directed over the catalytic surface, the moisture and carbon dioxide react exothermally with the lithium, producing localized heat. This surface heat acts to keep the catalyst dried out and impervious to the moisture contained in the air stream. Because the heat is localized, it is desirable to ensure a homogeneous distribution of the lithium throughout the catalyst.
  • yttrium is added, e.g., in an amount of approximately 3% by weight (relative to the weight of the hopcalite) , in order to control the rate of the forward reaction of the exotherm.
  • Lanthanum may also be added in a fractional amount.
  • impregnation is effected using a modified hopcalite Type 21215 material in a low temperature wash coat
  • the hopcalite is combined with zeolite.
  • the hopcalite is surface-modified as described above, through an electrochemical plasma activation process.
  • the fractions of the metal oxides in this outer coating layer are approximately as follows: manganese dioxide (0.75); copper (II) oxide (0.15); and cobalt (II & III) oxide (0.10).
  • the outer coating layer is applied in an amount such that the outer coating layer constitutes approximately 30% by weight of the total weight of the catalyst and support medium (e.g., non- woven fiber).
  • the preferred approach is to first coat the polyester non-woven substrate with an alumina wash coat in an aqueous salt solution. Then, using a slurry of finely ground hopcalite (5-20 microns), mixed with the cobalt (II & III) oxide, and an
  • a thick layer is deposited on the media.
  • the catalytic coated substrate is dipped in a dilute solution of ethyl alcohol and water containing 5% by weight chloroplantic acid.
  • the substrate is removed and dried in air at 150-200 degrees Fahrenheit, and then heated in a 300-350 degrees Fahrenheit oven for at least 5-7 minutes.
  • the carrier temperature should not exceed 300 degrees Fahrenheit.
  • the copper manganese, or hopcalite, wash coating deposition process can be substituted by either a spraying operation or a dip-coating operation.
  • hopcalite catalyst type 21215 available from Callery
  • Catalyst 21215 powder 100 parts by weight Kelzan 0.2 parts by weight
  • Binder 6 parts by weight
  • the binders can be selected from, but not limited to, a silicon resin solvent, a monobasic
  • the preferred binder is one that requires a processing temperature of less than 300 degrees Fahrenheit.
  • the slurry is deposited onto the non-woven material by dipping and air drying at 100-120 degrees
  • the non-woven media is cured in a gas-fired or other-heated oven. It may be necessary to fire the coating after each dipping operation to ensure the coating does not spall.
  • the non-woven material is soaked in a salt solution containing the respective metals, and then fired to convert the
  • the pieces are soaked in a saturated solution of ammonia and water for approximately
  • the non-woven carriers are soaked for at least a 5 minute period in the salt solution, then air dried at 100-120 degrees Fahrenheit.
  • the non-woven media is heated to approximately 280-300 degrees Fahrenheit in a reducing atmosphere until all the salts have decomposed. A change in weight does not occur.
  • a preferred solution for soaking the substrate is as follows: deionized water or acetic acid, 100 parts by weight; manganese II and nitrate x hydrate, 50 parts by weight; copper II nitrate trihydrate, 50 parts by weight; and zinc nitrate hexahydrate, 30 parts by weight.
  • the substrates After the non-woven media, impregnated by the catalyst, is soaked for at least 5-15 minutes, and air dried at 100-120 degrees Fahrenheit, the substrates are heated in a reducing atmosphere to a sufficient
  • the substrate After soaking the substrate in the solution, for 5-15 minutes, the substrate is removed and dried in air at approximately 110 degrees Fahrenheit. When dry the substrate is purged, then heated to 280-300 degrees
  • the substrate is maintained at temperature in the reducing atmosphere for a sufficient time and to allow the salts to decompose.
  • the process of soaking, drying, and firing is repeated until between 10-15% by weight of the support has been deposited.
  • An alternative process for the mixture of copper manganese and zinc oxide can be applied as a slurry to the substrate carrier.
  • the oxides in the ratio of 10 parts of copper II oxide to 6 parts of zinc oxide can be applied in a slurry similar to that proposed earlier for the 21215 mixture.
  • Another method by which the catalytic material can be applied onto the non-woven media is by first spraying a tackifier coat of a variety of adhesives onto the non-woven media, and then applying the catalytic material in a granular, or pelletized, form.
  • wash coat formulations for applying a hopcalite/zeolite mixture to a non-woven fibrous carrier.
  • hopcalite- zeolite coating on filter 26
  • hopcalite alone may be utilized to apply hopcalite alone to filter 26
  • zeolite to filter 30 may be utilized to wash coat calcium carbonate onto ceramic filter 28.
  • the dwell time through the catalytic filter is to be within the range of 90-120 milliseconds.
  • the particulate filter which is also impregnated with the catalyst, is comprised of a polyester non-woven media in ranges of 4.5 denier up to 200 denier.
  • the purpose of the dual catalytic infiltration system is to provide particulate removal efficiencies in the range of 40-65%; at the same time, provide a high efficiency (60-85%) removal of carbon monoxide as a result of the copper manganese
  • the service life of the catalytic filter is determined by the clogging or particulate capture rate of the material.
  • the amount of catalyst and the type of binder used for an application depends upon several factors. How these are selected can be described generally with reference to the catalytic mechanisms that occur in the reaction process.
  • the behavior of a gas-phase heterogeneous catalyst in an operating environment is influenced by three transport phenomena, which will be described with reference to a catalyst bed model. As the gas, or contaminant passes through the interstices of the
  • concentration gradient and possibly a temperature gradient, will develop between the inlet and outlet of the control device, or filter media substrate. This is called axial gradient. Also, concentrations in
  • interreactor transport inductive and diffusive heat and mass transfer phenomena
  • Mass transport resistance inside a porous catalyst reduces the overall reaction rate with respect to the intrinsic rate.
  • Intra-pellet heat transport resistance increases the overall rate of exothermic reactions and increases the rate of endothermic reactions.
  • the physical characteristics of the catalyst are such that, in actual service, the intra-pellet concentration gradient is far more influential than the intra-pellet temperature gradient.
  • Porous catalysts can provide up to hundreds of square meters of reactive surface per gram of pellet.
  • Reactants diffuse through the pores to the active surface and reactions occur. Products then diffuse out through the pores to the surface of the pellet. Generally, the minute, irregularly shaped pores branch and connect in a fairly random manner. Because pore geometry is not well understood or classified, its characterization remains partly empirical.
  • the mean free path of the diffusing molecule is much smaller than the pore diameter, i.e., the
  • the diffusive transport mode is called Pick's diffusion.
  • the molar flux of binary gas mixture in pores of a catalyst (J i , the rate of diffusion in the direction "z") is proportional to the concentration gradient in the direction of diffusion.
  • the proportional concentration gradient is:
  • C i is the concentration of component i at the catalyst surface (g-moles/cm 3 ), and z is distance in the direction of diffusion.
  • 0.001858 is a diffusive constant based upon temperature
  • P is total pressure in atmospheres
  • ⁇ 2 ij is the square of the constant force applied to the catalyst surface
  • ⁇ D is the integral rate of collision of the gas molecules in contact with the catalyst surface.
  • Knudsen's Diffusion Knudsen's Diffusion.
  • the diffusing molecules are adsorbed and desorbed in a random direction, i.e. the molecules do not bounce off the walls like billiard balls, but momentarily stick to the walls before being released. Knudsen's Diffusion has been correlated in the following equation:
  • D eff diffusivity
  • D eff,i is the effective diffusivity of component i in a multi-component mixture (cm 2 /s) ;
  • D k is the Knudsen
  • Intra-pellet heat conduction will be slow compared to the rate of heat generated by the reaction (exothermic) and can create a temperature gradient in a catalyst pellet.
  • the gradient if significant, can affect reaction rate via the following development:
  • T M T s + (- ⁇ HD eff,i /K s )C i
  • T M is the maximum catalyst temperature
  • T s is the catalyst surface temperature
  • ⁇ H is the heat of reaction
  • D eff,i is the effective diffusivity of component i in a multi-component mixture
  • K s is the thermal conductivity of the catalyst pellet
  • C i is the concentration gradient of component i at the catalyst surface.
  • k g is the gas mass-transfer coefficient
  • C i is the concentration of component i at the catalyst surface
  • C* i is the concentration of component 1 at the catalyst
  • h g is the gas heat transfer coefficient
  • T b is the bulk gas temperature
  • T. is the catalyst surface temperature
  • k s is the thermal conductivity of the catalyst pellet.
  • the mass transport resistance is determined for surface modified hopcalite, as well as hopcalite in which lithium has been added. This can be accomplished using Fick's diffusion equation (J ij ). After yttrium has been added, the total thermal conductivity (Knudsen's diffusion) of the catalyst mix can be
  • V bed the catalyst volume
  • V bed 60 Q COM / SV
  • Q COM is the flow rate of the gas stream (standard cubic feet per minute (SCFM)) and SV is the space
  • the mass transport resistance and thermal conductivity may indicate a desirable maximum space velocity of 10,000 cubic feet/hour, in order to allow sufficient (minimum) dwell time for optimum conversion. If the design flow rate of the gas is 2500 CFM, then the catalyst area would equal 15 cubic feet. If a smaller amount of catalyst were to be used, for example, 5 cubic feet, the velocity over the catalyst surface would increase to 30,000 CFH and the removal efficiency would decrease typically from about 99% to less than 90%.
  • the dwell time and capture rate are increased by the addition of lithium, in the form of lithium nitrate or lithium hydroxide, which will affect the mass transport resistance of the catalyst surface. It has been found that lithium reacts with carbon dioxide and water and heats the catalyst. This has the effect of heating the catalyst toward the light off temperature, which will increase the catalytic action, and also keeping the copper-manganese active sites dry.
  • the capture rate may be slowed down by the addition of yttrium, which affects the pore diffusion, to the wash coating formulation.
  • the addition of lithium to the catalyst enhances and improves the mass transfer resistance and thus the binary diffusion coefficient of the catalyst material (which can be calculated by Fick's equation). This is due to the fact that lithium gives off a high exotherm when in contact with carbon dioxide and water vapors. This exotherm serves to surface heat the catalyst heat mass transfer.
  • an emission component such as acetone
  • the exothermic reaction of lithium tends to increase temperature at the reaction sites.
  • the addition of yttrium which turns into a superconductor at elevated temperatures, acts to thermally stabilize the carrier and prevent excess build up of heat, which could otherwise cause thermal decomposition of the catalyst.
  • the yttrium thus acts as a thermal limit switch to maintain the exothermic reaction and at the same time not allow a thermal runaway condition to develop which would
  • lithium in an amount of 15% by weight of the modified hopcalite is employed, and added to the hopcalite prior to irradiation.
  • the amount of lithium may adjusted dependent upon the calculated values of Fick's coefficient and the

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Abstract

Filtre servant à éliminer les particules en suspension dans l'air, contenant un catalyseur permettant de neutraliser les gaz nocifs par un procédé de craquage catalytique moléculaire d'hydrocarbures lourds à température ambiante. De préférence le filtre est recouvert d'une hopcalite modifiée en surface, afin d'oxyder le monoxyde de carbone et de convertir l'ozone en oxygène. Le filtre peut être également recouvert d'un composé combinant la hopcalite et un autre catalyseur, tel que la zéolite. Le filtre peut être constitué d'un support de filtre fibreux, qui est recouvert par lavage avec une suspension épaisse de catalyseur.
PCT/US1992/008188 1991-09-27 1992-09-25 Filtre fibreux enduit pour le craquage catalytique Ceased WO1993005868A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US76672391A 1991-09-27 1991-09-27
US07/766,723 1991-09-27

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WO1993005868A1 true WO1993005868A1 (fr) 1993-04-01

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PCT/US1992/008188 Ceased WO1993005868A1 (fr) 1991-09-27 1992-09-25 Filtre fibreux enduit pour le craquage catalytique

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2140811C1 (ru) * 1998-11-03 1999-11-10 Дыкман Аркадий Самуилович Способ очистки промышленных газовых выбросов от органических кислородосодержащих соединений
RU2279314C2 (ru) * 2000-10-11 2006-07-10 Зюд Кеми Мт С.Р.Л. Катализатор для полного окисления летучих органических соединений
WO2012016051A2 (fr) 2010-07-30 2012-02-02 R. J. Reynolds Tobacco Company Élément filtre comprenant un matériau fibreux multifonction altérant la fumée
WO2013043806A2 (fr) 2011-09-23 2013-03-28 R. J. Reynolds Tobacco Company Produit à fibres mixtes pour l'utilisation dans la fabrication d'éléments de filtre de cigarette, et procédés, systèmes et appareils associés
WO2014018645A1 (fr) 2012-07-25 2014-01-30 R. J. Reynolds Tobacco Company Ruban de fibre mixte destiné à être utilisé dans la fabrication d'éléments de filtre de cigarette
RU2676642C1 (ru) * 2018-02-05 2019-01-09 Общество С Ограниченной Ответственностью "Газпром Трансгаз Краснодар" Способ комплексной очистки дымовых газов
EP4241584A2 (fr) 2012-10-10 2023-09-13 R. J. Reynolds Tobacco Company Matériau de filtre pour élément de filtre d'un article pour fumeur et procédé associé

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2140811C1 (ru) * 1998-11-03 1999-11-10 Дыкман Аркадий Самуилович Способ очистки промышленных газовых выбросов от органических кислородосодержащих соединений
RU2279314C2 (ru) * 2000-10-11 2006-07-10 Зюд Кеми Мт С.Р.Л. Катализатор для полного окисления летучих органических соединений
WO2012016051A2 (fr) 2010-07-30 2012-02-02 R. J. Reynolds Tobacco Company Élément filtre comprenant un matériau fibreux multifonction altérant la fumée
US8720450B2 (en) 2010-07-30 2014-05-13 R.J. Reynolds Tobacco Company Filter element comprising multifunctional fibrous smoke-altering material
US9119420B2 (en) 2010-07-30 2015-09-01 R.J. Reynolds Tobacco Company Filter element comprising multifunctional fibrous smoke-altering material
WO2013043806A2 (fr) 2011-09-23 2013-03-28 R. J. Reynolds Tobacco Company Produit à fibres mixtes pour l'utilisation dans la fabrication d'éléments de filtre de cigarette, et procédés, systèmes et appareils associés
US10064429B2 (en) 2011-09-23 2018-09-04 R.J. Reynolds Tobacco Company Mixed fiber product for use in the manufacture of cigarette filter elements and related methods, systems, and apparatuses
EP3456212A1 (fr) 2011-09-23 2019-03-20 R. J. Reynolds Tobacco Company Produit à fibres mixtes à utiliser dans la fabrication d'éléments de filtre de cigarette et procédés, systèmes et appareils connexes
WO2014018645A1 (fr) 2012-07-25 2014-01-30 R. J. Reynolds Tobacco Company Ruban de fibre mixte destiné à être utilisé dans la fabrication d'éléments de filtre de cigarette
EP4241584A2 (fr) 2012-10-10 2023-09-13 R. J. Reynolds Tobacco Company Matériau de filtre pour élément de filtre d'un article pour fumeur et procédé associé
RU2676642C1 (ru) * 2018-02-05 2019-01-09 Общество С Ограниченной Ответственностью "Газпром Трансгаз Краснодар" Способ комплексной очистки дымовых газов

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