CA1056579A - Powder-and-gas reactions - Google Patents
Powder-and-gas reactionsInfo
- Publication number
- CA1056579A CA1056579A CA218,828A CA218828A CA1056579A CA 1056579 A CA1056579 A CA 1056579A CA 218828 A CA218828 A CA 218828A CA 1056579 A CA1056579 A CA 1056579A
- Authority
- CA
- Canada
- Prior art keywords
- conveyor
- chute
- powder
- gas
- reaction
- 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.)
- Expired
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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
-
- 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
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/16—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with particles being subjected to vibrations or pulsations
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G53/00—Compounds of nickel
- C01G53/04—Oxides; Hydroxides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
-
- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/19—Details relating to the geometry of the reactor
- B01J2219/194—Details relating to the geometry of the reactor round
- B01J2219/1941—Details relating to the geometry of the reactor round circular or disk-shaped
- B01J2219/1944—Details relating to the geometry of the reactor round circular or disk-shaped spiral
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- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to a method of and apparatus for bringing about reactions between a powder and a gas, in which the contact between the powder and reaction gas produces a chemical reaction. Powdery material flows downwardly along a vibratory spiral conveyor chute, while gas flows counter to the powder, preferably in excess. Mixing ramp arrangements are provided in the chute. These involve inclined ramp surfaces dividing the powder stream into two layers, and provisions for causing the initially uppermost layer to tumble down onto the chute bottom while the initially lowermost layer is still supported on its ramp. The latter then drops down, too, and now becomes the uppermost layer. The present invention is faster and provides a more uniform reaction and resultant product than known batch processing in roasting ovens.
This invention relates to a method of and apparatus for bringing about reactions between a powder and a gas, in which the contact between the powder and reaction gas produces a chemical reaction. Powdery material flows downwardly along a vibratory spiral conveyor chute, while gas flows counter to the powder, preferably in excess. Mixing ramp arrangements are provided in the chute. These involve inclined ramp surfaces dividing the powder stream into two layers, and provisions for causing the initially uppermost layer to tumble down onto the chute bottom while the initially lowermost layer is still supported on its ramp. The latter then drops down, too, and now becomes the uppermost layer. The present invention is faster and provides a more uniform reaction and resultant product than known batch processing in roasting ovens.
Description
~OS6579 SPECIFICATION
This invention relates to a method of and apparatus for bringing about reactions between a powder and a gas, in which the contact between the powder and reaction gas produces a chemical reaction. The term chemical reaction is generic, as used herein, to include reactioas whether substitution, ex-change, replacement~ addition~ or other.
To bring about reactions between powdery and gaseous subs~ances there have been used in the art roasting ovens, rotary kilns or ~luidized bed arrangements, and scrubbing columns.
In an oven, the powder to be treated is processed in batches, involving deposition o~ a relatively thick layer on a grate. me thick layers which are required to process suf-ficiently large quantities, together with the poor diffusion which prevails, lead to non-uniform reactions. Moreover, these pro-cesses take a long time. The resultant products are non~uniform in structure and chemical properties.
Rotary kilns permit ~higher throughput, and continuous in-and output. ~owever, the non-uniform distribution of the powder to be ereated along the wall of the reaction vessel also pre~ents for~ation of a completely homogeneous praduct. The availability of contact between gas and-~powder is limited by the interior surface area and the speed of rotation of the reactor.
Treatment in fluidiæed beds is difficul~ in large scale applications, and especially so when a powder ic involved which has small grain size, or which has a broad distributioa
This invention relates to a method of and apparatus for bringing about reactions between a powder and a gas, in which the contact between the powder and reaction gas produces a chemical reaction. The term chemical reaction is generic, as used herein, to include reactioas whether substitution, ex-change, replacement~ addition~ or other.
To bring about reactions between powdery and gaseous subs~ances there have been used in the art roasting ovens, rotary kilns or ~luidized bed arrangements, and scrubbing columns.
In an oven, the powder to be treated is processed in batches, involving deposition o~ a relatively thick layer on a grate. me thick layers which are required to process suf-ficiently large quantities, together with the poor diffusion which prevails, lead to non-uniform reactions. Moreover, these pro-cesses take a long time. The resultant products are non~uniform in structure and chemical properties.
Rotary kilns permit ~higher throughput, and continuous in-and output. ~owever, the non-uniform distribution of the powder to be ereated along the wall of the reaction vessel also pre~ents for~ation of a completely homogeneous praduct. The availability of contact between gas and-~powder is limited by the interior surface area and the speed of rotation of the reactor.
Treatment in fluidiæed beds is difficul~ in large scale applications, and especially so when a powder ic involved which has small grain size, or which has a broad distributioa
-2-~ 6579 of grain sizes. The residence time of the different grain size fractions difers, and this creates the risk that non-homogeneous products ~ill result.
To react gases with solids, so-called vertical kilns or other columns such as scrubbers may be utilized. In these the powder is poured into a container through which the gas flows generally from bottom to top.
Such arrangements can only be opera~ed discontinuously in a ba~ch process, and the powder must have predetermined grain sizes to permit gas passage and also keep the diffusion path short. Furthermore, channels can easily form in the charge, through which the gas escapes.
This invention relates ~o the method of processing a powdery material containing material capable of being a catalyst, utilizing a vibra~ory spiral conveyor which includes a spiral chute having its axis positioned generally vertically, a chamber enclosing the chute and means for producing axial vibration of the chute, the method comprising the steps of:
introducing the powdery material at the top of the chute while causing the chute to reciprocate along its axis so as to cause the material to vibratingly move downward along the chute in a substantially uniform thickness layer;
passing reaction gas in counterflow manner respective the powder so as to contact and react with the powder layer moving down the chute, the vibratory movement producing an alternating pumping and suction effect which improves the convective access of the gas to the powdery material and thereby the reaction; maintaining gas and powder temperatures appropriate for the reaction;
removing the gaseous reaction products near the top of the spiral conveyor;
and wi~hdrawing the processed catalyst material near the bottom of the spiral conveyor.
This invention further relates to apparatus for carrying out a reaction between a powdery material and a gas, comprising a vibratory helical conveyor having a vertical or substantially vertical axis and being enclosed in a gas-~ight casing, the conveyor being provided with supply and discharge conduits for the gas, heating and/or cooling means provided under the helical turns of the conveyor, and mixing devices in or on the helical turns of the conveyor.
- ~ - 3 -~(:1 5~S79 The invention provides a continuous process for carrying on reactions between powdery and gaseous substances> by means of which homo-geneous and highly active products are obtained in comparatively short time.
The powdery material is introduced from the top into a vibratory spiral conveyor, maintained at reaction temperature, and surrounded by a gas-tight housing. The continuous layer of such material covering the bottom of the conveyor chute is brought into contact with the reaction gas travers-ing the spiral conveyor in counterflow direction. The ga.seous reaction pro-ducts. if any, are removed~ together wi~h the reaction gas stream, at the topof the spiral conveyor. The powdery reaction product is withdrawn at the bottom end of the vibratory spiral conveyor. Ideally, the process is - 3a -, J
~alSI~S'79 carried out continuously, either by continuous feeding and/or continuouS removing of product. If the reaction is exothermic no heating is requlred, indeed cooling may be appropriate; when the reaction sequires heating, such is supplied.
~le apparatus for practicing the method of the in~
vention comprises a vibratory spiral conveyor within a gas-tight housing, a reaction gas inlet and outlet means or the spiral conveyor, a heater means placed below the conveyor chute, and mixing means placed within the conveyor path.
o Such a method and apparatus are particularly useful for the production of active metallic powders and catalysts, such as oxidation-, reduction- or hydration- catalysts, as well as in the production on a large scale of active mass for galvanic elements. However, the method and apparatus have wide appli-cability wherever one or more particular powdery material is to be reacted with a gas.
For further details reference is made to the discus~sion which fo~lows, in the light of the accompanying drawings9 wherein Figure 1 shows, in diagramma~ic form, an overall illustration of an embodiment of the invention; and Figures 2a and 2b show perspective views taken from opposite directions of a mixing arrangement for the powdery materisl processed in the embodimen~ of Figure 1.
Referring to Figure 19 this shows a spiral conveyor 1 provided with a gas-tight enclosure consisting of two double-walled half shells 8, whose interstices are filled with silicate ~S65'7~
beads for thermal insulation~ This enclosure can fur~her be surrounded with batting 9 of glass wool.
At the bottom a vibratory drive is provided which may utilize, for example, an oscillating magnet 7 or an eccen~ric motor drive (not shown).
Where air is used as the reaction gas, the vibratory spiral conveyor and its surrounding apparatus need not be purged of air by passage of nitrogen before being put into operation;
but nitrogen is used where air is not the reaction gas. Sub-sequently~ the nitrogen is evacuated by entrainment with the reaction gas. The appropriate reaction gas pressure is then established~ and the reactor is brought to its reaction tem-perature. The powdery material is then introduced, via a dosing trough~ continuously from above into the~inlet duct 10-of~the spiral conveyor. The-~powdery material flows along conveyor chute 4, which may be heated by a heating arrangement placed beneath it, e.g. by heating rods 5, or it may be cooled by appropriate cooling means. The powdery material is intermixed by means of seYeral mixing means positioned along the con~eyor chute. The comparatively thin layer of powdery material thus moving from top to bottom is brought into contact with an excess of reaction gas flowing along the spiral conveyor in counter-flow direction. This gas is introduced through inlets 11 at different heights along the vibratory spiral ConJeyor. At the lower end of the spiral conveyor, the powdery material is continuously~withdrawn through an outlet duct 13. The gaseous i~S6579 reaction products are exhaustad, along with the reaction gas stream, and are freed in conventional manner of the entrained fine powder dust.
It has proven particularly desirable to use, as mixing means, mixing ramp arrangements 6 positioned within conveyor chute 4. Once such mlxing ramp arrangement 6 is shown in Figures 2a and 2b in perspective views taken from opposite sides. It includes two surfaces 62, 63, separated from each other by a vertical partition 61. The upper surface 62 starts from the middle of the cross-section of the powder layer within the duct.
The lower surface 63 starts from the bottom of the conveyor chute.
Both rlse along partition 61~ in the direction in which the powder being mixed moves along the conveyor chute. Upper surface 62 is provided with an up-turned lip 64 which bounds-that surface in the direction of powder movement. A space ~s provided be-tween partition 61 and the side wall of conveyor chute 4.
By means of this mixing ramp arrangement 6 the cross-section of the powdery lay~r is divided into two horizontally superposed halves. The half-layer which moves along the upper surface 62 drops off that surface and becomes deposited beneath the slightly rising lower surface 63, whereas the half-layer guided onto lower surface 63 drops over edge 65 onto the powder half-layer which emerges from beneath that edge.
If desired, there may also be cut out of up~turned lip 64 the portion indicated by dot-dash line 66 in Figures 2a and 2b. This permits powder moving up surface 62 to be discharged 1~5~g onto surface 63 in case the space between the sidewall of chute 4 and partition 61 becomes clogged, thereby inhibiting the normal flow of material.
Among the e~amples which follow, E~amples 2 to 4 further describe the production of several catalysts, as well as of active mass ~or galvanic elements utilizing the method of the invention.
These examples are not to be construed as limitative, but are by way of illustration only.
By use of that method, other chemical reactions like substitutions may be carried out on a continuous basis. Such reactions are further described in Examples 5 and 6.
EXA~PLE- 1 PRODUCTION OF A COPPB CHROMITe CATALYST FOR
SELECTIVE HYDRATION1 U?ILIZING AIR AS OXIDIZING GAS
In an ammonia solution, a di-chro~ate is obtained as a fine powder by precipitation with sodium chromate from copper nitrate. The composition hzs the for~ula ~Cu(NH3)2~
(NH4~2 , ~CrO4)2 . This powder is thoroughly washed and sub-stantially freed of water by drying. Subsequently, the powder is continuously decomposed in the spiral con~eyor reactor by counterflow of a preheated air current, at 300 to 350C and with a lay~r thickness of 10 to 20 mm. This involves the following reaction:
LCU(NH3)2~ . (NH4)2 (CrG4)2 ~ CUO . Cr2O3 + N2 + NH3 + H2O
~OS65'7g The gaseous reaction products are removed throughcondensation (H20) and scrubbing with water (NH3). The nitrogen is purged out with the air stream. The grain siæe may be varied within wide limits depending upon the grain size of the di.chromate. The catalyst produced in this manner is par-ticularly suitable for selective reduction of carbonyl groups:
aldehydes and ketones are reduced to alcohols, esters~ and carbo~ylic acids. Likewise amides are reduced to amines.
E _ PRODUCTION OF A NICKEL CARRIER CATALYST FOR
LARGE SCALE FAT RENDE~ING
The mass of a nickel carrler catalyst consists of basic nickel carbonate precipitated onto silicate beads~ It is intro-duced continuously into the spiral-conveyor reactor, at a reaction temperature between 350 and 500C and a layer depth between 1 and 10 mm, Hydrogen gas is introduced in counterflow manner in excess (about 10 times stochiometric). The hydrogen is heated to the reaction temperature before introduction into the reactor. At a residence time between 5 and 20 minutes, the basic carbonate is then completely reduced to very ~inely divided nickel. This endothermic reaction takes place in accord-ance with the following equations:
Ni(OH)2 +~H2 350 -_500 C ~ Ni ~ 2 H20 NiCO + H 350 - 500 C Ni + CO + H O
To react gases with solids, so-called vertical kilns or other columns such as scrubbers may be utilized. In these the powder is poured into a container through which the gas flows generally from bottom to top.
Such arrangements can only be opera~ed discontinuously in a ba~ch process, and the powder must have predetermined grain sizes to permit gas passage and also keep the diffusion path short. Furthermore, channels can easily form in the charge, through which the gas escapes.
This invention relates ~o the method of processing a powdery material containing material capable of being a catalyst, utilizing a vibra~ory spiral conveyor which includes a spiral chute having its axis positioned generally vertically, a chamber enclosing the chute and means for producing axial vibration of the chute, the method comprising the steps of:
introducing the powdery material at the top of the chute while causing the chute to reciprocate along its axis so as to cause the material to vibratingly move downward along the chute in a substantially uniform thickness layer;
passing reaction gas in counterflow manner respective the powder so as to contact and react with the powder layer moving down the chute, the vibratory movement producing an alternating pumping and suction effect which improves the convective access of the gas to the powdery material and thereby the reaction; maintaining gas and powder temperatures appropriate for the reaction;
removing the gaseous reaction products near the top of the spiral conveyor;
and wi~hdrawing the processed catalyst material near the bottom of the spiral conveyor.
This invention further relates to apparatus for carrying out a reaction between a powdery material and a gas, comprising a vibratory helical conveyor having a vertical or substantially vertical axis and being enclosed in a gas-~ight casing, the conveyor being provided with supply and discharge conduits for the gas, heating and/or cooling means provided under the helical turns of the conveyor, and mixing devices in or on the helical turns of the conveyor.
- ~ - 3 -~(:1 5~S79 The invention provides a continuous process for carrying on reactions between powdery and gaseous substances> by means of which homo-geneous and highly active products are obtained in comparatively short time.
The powdery material is introduced from the top into a vibratory spiral conveyor, maintained at reaction temperature, and surrounded by a gas-tight housing. The continuous layer of such material covering the bottom of the conveyor chute is brought into contact with the reaction gas travers-ing the spiral conveyor in counterflow direction. The ga.seous reaction pro-ducts. if any, are removed~ together wi~h the reaction gas stream, at the topof the spiral conveyor. The powdery reaction product is withdrawn at the bottom end of the vibratory spiral conveyor. Ideally, the process is - 3a -, J
~alSI~S'79 carried out continuously, either by continuous feeding and/or continuouS removing of product. If the reaction is exothermic no heating is requlred, indeed cooling may be appropriate; when the reaction sequires heating, such is supplied.
~le apparatus for practicing the method of the in~
vention comprises a vibratory spiral conveyor within a gas-tight housing, a reaction gas inlet and outlet means or the spiral conveyor, a heater means placed below the conveyor chute, and mixing means placed within the conveyor path.
o Such a method and apparatus are particularly useful for the production of active metallic powders and catalysts, such as oxidation-, reduction- or hydration- catalysts, as well as in the production on a large scale of active mass for galvanic elements. However, the method and apparatus have wide appli-cability wherever one or more particular powdery material is to be reacted with a gas.
For further details reference is made to the discus~sion which fo~lows, in the light of the accompanying drawings9 wherein Figure 1 shows, in diagramma~ic form, an overall illustration of an embodiment of the invention; and Figures 2a and 2b show perspective views taken from opposite directions of a mixing arrangement for the powdery materisl processed in the embodimen~ of Figure 1.
Referring to Figure 19 this shows a spiral conveyor 1 provided with a gas-tight enclosure consisting of two double-walled half shells 8, whose interstices are filled with silicate ~S65'7~
beads for thermal insulation~ This enclosure can fur~her be surrounded with batting 9 of glass wool.
At the bottom a vibratory drive is provided which may utilize, for example, an oscillating magnet 7 or an eccen~ric motor drive (not shown).
Where air is used as the reaction gas, the vibratory spiral conveyor and its surrounding apparatus need not be purged of air by passage of nitrogen before being put into operation;
but nitrogen is used where air is not the reaction gas. Sub-sequently~ the nitrogen is evacuated by entrainment with the reaction gas. The appropriate reaction gas pressure is then established~ and the reactor is brought to its reaction tem-perature. The powdery material is then introduced, via a dosing trough~ continuously from above into the~inlet duct 10-of~the spiral conveyor. The-~powdery material flows along conveyor chute 4, which may be heated by a heating arrangement placed beneath it, e.g. by heating rods 5, or it may be cooled by appropriate cooling means. The powdery material is intermixed by means of seYeral mixing means positioned along the con~eyor chute. The comparatively thin layer of powdery material thus moving from top to bottom is brought into contact with an excess of reaction gas flowing along the spiral conveyor in counter-flow direction. This gas is introduced through inlets 11 at different heights along the vibratory spiral ConJeyor. At the lower end of the spiral conveyor, the powdery material is continuously~withdrawn through an outlet duct 13. The gaseous i~S6579 reaction products are exhaustad, along with the reaction gas stream, and are freed in conventional manner of the entrained fine powder dust.
It has proven particularly desirable to use, as mixing means, mixing ramp arrangements 6 positioned within conveyor chute 4. Once such mlxing ramp arrangement 6 is shown in Figures 2a and 2b in perspective views taken from opposite sides. It includes two surfaces 62, 63, separated from each other by a vertical partition 61. The upper surface 62 starts from the middle of the cross-section of the powder layer within the duct.
The lower surface 63 starts from the bottom of the conveyor chute.
Both rlse along partition 61~ in the direction in which the powder being mixed moves along the conveyor chute. Upper surface 62 is provided with an up-turned lip 64 which bounds-that surface in the direction of powder movement. A space ~s provided be-tween partition 61 and the side wall of conveyor chute 4.
By means of this mixing ramp arrangement 6 the cross-section of the powdery lay~r is divided into two horizontally superposed halves. The half-layer which moves along the upper surface 62 drops off that surface and becomes deposited beneath the slightly rising lower surface 63, whereas the half-layer guided onto lower surface 63 drops over edge 65 onto the powder half-layer which emerges from beneath that edge.
If desired, there may also be cut out of up~turned lip 64 the portion indicated by dot-dash line 66 in Figures 2a and 2b. This permits powder moving up surface 62 to be discharged 1~5~g onto surface 63 in case the space between the sidewall of chute 4 and partition 61 becomes clogged, thereby inhibiting the normal flow of material.
Among the e~amples which follow, E~amples 2 to 4 further describe the production of several catalysts, as well as of active mass ~or galvanic elements utilizing the method of the invention.
These examples are not to be construed as limitative, but are by way of illustration only.
By use of that method, other chemical reactions like substitutions may be carried out on a continuous basis. Such reactions are further described in Examples 5 and 6.
EXA~PLE- 1 PRODUCTION OF A COPPB CHROMITe CATALYST FOR
SELECTIVE HYDRATION1 U?ILIZING AIR AS OXIDIZING GAS
In an ammonia solution, a di-chro~ate is obtained as a fine powder by precipitation with sodium chromate from copper nitrate. The composition hzs the for~ula ~Cu(NH3)2~
(NH4~2 , ~CrO4)2 . This powder is thoroughly washed and sub-stantially freed of water by drying. Subsequently, the powder is continuously decomposed in the spiral con~eyor reactor by counterflow of a preheated air current, at 300 to 350C and with a lay~r thickness of 10 to 20 mm. This involves the following reaction:
LCU(NH3)2~ . (NH4)2 (CrG4)2 ~ CUO . Cr2O3 + N2 + NH3 + H2O
~OS65'7g The gaseous reaction products are removed throughcondensation (H20) and scrubbing with water (NH3). The nitrogen is purged out with the air stream. The grain siæe may be varied within wide limits depending upon the grain size of the di.chromate. The catalyst produced in this manner is par-ticularly suitable for selective reduction of carbonyl groups:
aldehydes and ketones are reduced to alcohols, esters~ and carbo~ylic acids. Likewise amides are reduced to amines.
E _ PRODUCTION OF A NICKEL CARRIER CATALYST FOR
LARGE SCALE FAT RENDE~ING
The mass of a nickel carrler catalyst consists of basic nickel carbonate precipitated onto silicate beads~ It is intro-duced continuously into the spiral-conveyor reactor, at a reaction temperature between 350 and 500C and a layer depth between 1 and 10 mm, Hydrogen gas is introduced in counterflow manner in excess (about 10 times stochiometric). The hydrogen is heated to the reaction temperature before introduction into the reactor. At a residence time between 5 and 20 minutes, the basic carbonate is then completely reduced to very ~inely divided nickel. This endothermic reaction takes place in accord-ance with the following equations:
Ni(OH)2 +~H2 350 -_500 C ~ Ni ~ 2 H20 NiCO + H 350 - 500 C Ni + CO + H O
3 2 - ~ 2 2 ~:)5~i~79 These reactions are promoted by util$zing short diffusion paths for the gaseous reactants and by rapid removal of reaction water and carbon dioxide. Furth~rmore, the contin-uous occurrence of the reduction in a thin layer makes possible very uniform heat supply, which in turn assures a uniform pro-duct.
The gaseous reaction products ~C02, H20 vapor) en-trained in ~he hydrogen stream are removed without d$fficulty by absorption or condensation in a scrubbing column.
The catalysts produced in accordance with the for~-going process exhibit 10 to 20% higher hydrogenation activity than those produced by conventional processes.
PRODUCTION OF AN ELECTRO~HEMICALLY ACTIVE Ni(OH)2 - POWDER
~POSITIVE MASS FOR _LKALINE STORAGE BATTER~ES? _ Finely divided nickel (II) - oxalate (NiC204 ~grain size greater than 50 u~ is transported from top to bott~m in the spiral conveyor reactor at 150 to 250C and in a layer thickness of lO to 15 mm. Air saturated with wa~er at about 2 atmospheres above atmospheric pressure, preheated ~o about 300C, is supplied to the powder transport in counterflow manner. There takes place a decomposition (hydrothermic decomposition) of the nickel oxalate with formation of f$nely divided nickel hydroxide Ni (OH)2 according to the following reaction:
NiC24 + H20 Air Ni (OH)2 + C2 ~ CO
~05~5~9 The gaseous reaction products CO2 and C0 which are exhausted with air as the carrier gas are, after transformation of the Co through catalytic o~idation, discharged to the out-side as CO2.
The resulting nickel hydroxide powder of grain size ranging from 2 to 5 u has been proven particularly effectlve for use as the positive active mass in alkaline storage batteries.
It is emphasized that, because of the uniformly fine grain dis-tribution of the precipitating hydroxide~ the time consuming practices for storage batteries which have been customary9 have been able to be reduced from about 60 hours to about 20 to 25 hours.
Finally~ the current outputs, especially at high current flow, can be considerably increased because of the greater surface area and~the improved surface availability of the powder to the electrochemi~al processes taking place in the electrodes.
EX~MPLE 4 PRODUCTION OF NEGATIVE, PREHEATED CADMIUM MASSES WITH METALLIC
NICKEL CONDUCTIVE NATRIX FOR ALKALINE STORAGE BATTERIBS
A finely divided powder (grain size less than 10 u) consisting of mixed crystals of 10% nickel formate and 90%
cadmium formate is displaced continuously in the spiral conveyor reactor from top to bottom at a temperature of 270 to 290C and a layer thickness of 15 to 25 mm. Hydrogen preheated to the reaction temperature, is flowed counter-currently to the powder stream. The reactions which take place at this temperature within the reactor are shown by the following reactions:
~ss~9 Cd (HC02~2 ~ H2 27~ - 290 C Cd + ~ H20 ~ C0 Ni ~HC02~2 + H2 270 - 290~ Ni ~ 2 H20 ~ C0 A further example of a treatment of gases with powdery solids is scrubbing of C02 with molecular sieves. Molecular sieves are substances with high absorption capability for gases and vapors. For C0~ this absorptivity is sometimes greater than 15% by weight ae room temperature. At higher temperatures, i~e. 150C~ the ~reater proportion of the C02 is released.
These facts may be used for the removal of C02 from reforming exhaust gases. Such gas contains about 25Z~ C02 and about 75% H2. The gas is introduced from the bottom into a spiral conveyor in an amount of 55 nm3/h. In the conveyor chute~ which has a total surface area of 1 m2 and a length of 13 m, it flows counter to a granular layer of the molecular sieve material. Approximately 180 l/h of the molecular sieve material, corresponding to 275 kg/h, passes through the reactor.
At a laysr thickness of 2 cm this corresponds to a residence time of si~ minutes within the spiral conveyor~ The gas leaving the spiral conveyor at the top then contains only fractions of a per-cent of C02, whereas the charged molecular sieve material removed from the bottom of the spiral conveyor contains more than 10%
by weight of CO2O The reaction temperat~re is 25C- The heat produced during the reaction is removed by means of cooling pipes attached to the bottom of ~he conveyor bed.
~s6s~g It has proven useful to also regenerate the molecular sieve in a spiral conveyor. To this end, the granular material is introduced at the top while the conveyor bed is heated to 150 to 250C. Air streams into the conveyor path from~the bottom, and becomes charged with carbon dioxide on the way to-ward the top. This proress is particularly effective because it is a counterflow process, and the ultimate charge of the molecular sie~e material is kept very low due to the low C02 concentration in the air at the exit of the powder from the spiral conveyor.
The two spiral conveyor reactors for the absorption and desorption of the C02 may be united in a single installation with a closed, molecular sieve circulatory system. Preferably it also includes provision for buffer storage of a predetermined excess quantity~of the granular molecular sieve material.
The process described in this example may also be used, at suitably adjusted operating temperatures, for the re-moval of other~impurities i.e. undesirable gas ContaminantS from gas mixtures, e.g. H2S, NH3, benzene and methanol, to mention just a fewc For such cases, activated carbon powder or granular material may be used to good advantage instead of the molecular sieves.
EXAMPLE ~
Nickel carrier catalysts of the type described in Example 1~ contain among other impurities, nickel after they have been used for fat rendering. Befause of environmental pollution problems, this nickel content has been creating inCreaSing diffi-culties in the disposal of such wastes. Therefore a process iOS~;5'79 for recovering the nickel from the catalyst wastes is much sought after.
It has been found that it is possible to free the spent catalyst of nickel, after removal of the main fat quantities, by passing the material through a spiral conveyor reactor a few degrees below 100C, in counterflow to a CO gas stream. In the course ~of the reaction, carbonyl nickel is produced as an inter-mediate (unstable) compound, removed from the reactor by the circu-lating CO, and decomposed into nickel powder and CO at 180C.
In this way, the nicXel is recovered as a valuable material of high purity, and the carrier mass which leaves the spiral con-veyor at the bottom can be reused~
An additional class of processes in which use of the spiral conveyor or reactor is well suited, are catalytic gas treatment processes, in which regeneration of the catalyst is required after a predetermined reaction period. An example is the catalytic treatment of natural gas or petroleum deriva~ives which in many cases lead to pois~ning of the catalyst by sulfur content~ Continuous passage of the catalyst through the reactor permits its regeneration outside the reactor, with most economical utilization inside the reactor installation. T~is minimi~es the consumption of these usually expensive catalysts and thereby reduces the required investment of capital.
Other examples of the application of exchange processes in the spiral conveyor reactor of the invention are readily available to one skilled in the art. For instance, the drying _13-~L~S6579 of crystals and powders, in which the movement in the spiral conveyor counteracts the tendency of the crystals to agglomerate.
The roasting of sulfide materials is an example of the treatment of powdery solids with gases, in which the modification of the solid is the ob~ect of the process.
From these examples it is evident to one skilled in the art that the invention is particularly suitable for producing active metal powders with highly desirable characteristics~
Because of the wide applicability-of the process and apparatus, it is apparent that it is not the nature of the particular chemicals used but, the process of ope~ating the device of the invent~on and the device itself, which are the more important aspects of the invention.
Due to the fact that the powder grains are moved along by vibration, agglomeration is prevented. By increasing the amplitude of the vibration, even powder which does not flow easily can be treated. Because the gas is supplied in ex-cess, the equilibrium of the chemical reaction is displaced in favor of ~he end product and this reduces the residence time of the powder in the vibratory spiral conveyorO The impediments to diffusion which characterize previous known techniques, a~re considerably reduced by the mixing which is carried out in accordance with the invention by means of the mlxing ramp arrange-ments and by passing the reaction gas in counterflow manner~ Thus the heretofore customary residence times of a few hours can typically be reduced to a few minutes.
~056S7~
Because, in accordance with the invention, heat is supplied both from below by a heater arranaement positioned below the chute of the spiral conveyor, and from above (through radiation) and through convection by means of the reaction gas, very uniform heating of the powdery ~aterial is achieved. This also contributes appreciably to the uniformity of the end product achievable by means of the invention.
.
- , '', .
. - : . . ~
, ' : ~
:
, -`' ' ~
..
The gaseous reaction products ~C02, H20 vapor) en-trained in ~he hydrogen stream are removed without d$fficulty by absorption or condensation in a scrubbing column.
The catalysts produced in accordance with the for~-going process exhibit 10 to 20% higher hydrogenation activity than those produced by conventional processes.
PRODUCTION OF AN ELECTRO~HEMICALLY ACTIVE Ni(OH)2 - POWDER
~POSITIVE MASS FOR _LKALINE STORAGE BATTER~ES? _ Finely divided nickel (II) - oxalate (NiC204 ~grain size greater than 50 u~ is transported from top to bott~m in the spiral conveyor reactor at 150 to 250C and in a layer thickness of lO to 15 mm. Air saturated with wa~er at about 2 atmospheres above atmospheric pressure, preheated ~o about 300C, is supplied to the powder transport in counterflow manner. There takes place a decomposition (hydrothermic decomposition) of the nickel oxalate with formation of f$nely divided nickel hydroxide Ni (OH)2 according to the following reaction:
NiC24 + H20 Air Ni (OH)2 + C2 ~ CO
~05~5~9 The gaseous reaction products CO2 and C0 which are exhausted with air as the carrier gas are, after transformation of the Co through catalytic o~idation, discharged to the out-side as CO2.
The resulting nickel hydroxide powder of grain size ranging from 2 to 5 u has been proven particularly effectlve for use as the positive active mass in alkaline storage batteries.
It is emphasized that, because of the uniformly fine grain dis-tribution of the precipitating hydroxide~ the time consuming practices for storage batteries which have been customary9 have been able to be reduced from about 60 hours to about 20 to 25 hours.
Finally~ the current outputs, especially at high current flow, can be considerably increased because of the greater surface area and~the improved surface availability of the powder to the electrochemi~al processes taking place in the electrodes.
EX~MPLE 4 PRODUCTION OF NEGATIVE, PREHEATED CADMIUM MASSES WITH METALLIC
NICKEL CONDUCTIVE NATRIX FOR ALKALINE STORAGE BATTERIBS
A finely divided powder (grain size less than 10 u) consisting of mixed crystals of 10% nickel formate and 90%
cadmium formate is displaced continuously in the spiral conveyor reactor from top to bottom at a temperature of 270 to 290C and a layer thickness of 15 to 25 mm. Hydrogen preheated to the reaction temperature, is flowed counter-currently to the powder stream. The reactions which take place at this temperature within the reactor are shown by the following reactions:
~ss~9 Cd (HC02~2 ~ H2 27~ - 290 C Cd + ~ H20 ~ C0 Ni ~HC02~2 + H2 270 - 290~ Ni ~ 2 H20 ~ C0 A further example of a treatment of gases with powdery solids is scrubbing of C02 with molecular sieves. Molecular sieves are substances with high absorption capability for gases and vapors. For C0~ this absorptivity is sometimes greater than 15% by weight ae room temperature. At higher temperatures, i~e. 150C~ the ~reater proportion of the C02 is released.
These facts may be used for the removal of C02 from reforming exhaust gases. Such gas contains about 25Z~ C02 and about 75% H2. The gas is introduced from the bottom into a spiral conveyor in an amount of 55 nm3/h. In the conveyor chute~ which has a total surface area of 1 m2 and a length of 13 m, it flows counter to a granular layer of the molecular sieve material. Approximately 180 l/h of the molecular sieve material, corresponding to 275 kg/h, passes through the reactor.
At a laysr thickness of 2 cm this corresponds to a residence time of si~ minutes within the spiral conveyor~ The gas leaving the spiral conveyor at the top then contains only fractions of a per-cent of C02, whereas the charged molecular sieve material removed from the bottom of the spiral conveyor contains more than 10%
by weight of CO2O The reaction temperat~re is 25C- The heat produced during the reaction is removed by means of cooling pipes attached to the bottom of ~he conveyor bed.
~s6s~g It has proven useful to also regenerate the molecular sieve in a spiral conveyor. To this end, the granular material is introduced at the top while the conveyor bed is heated to 150 to 250C. Air streams into the conveyor path from~the bottom, and becomes charged with carbon dioxide on the way to-ward the top. This proress is particularly effective because it is a counterflow process, and the ultimate charge of the molecular sie~e material is kept very low due to the low C02 concentration in the air at the exit of the powder from the spiral conveyor.
The two spiral conveyor reactors for the absorption and desorption of the C02 may be united in a single installation with a closed, molecular sieve circulatory system. Preferably it also includes provision for buffer storage of a predetermined excess quantity~of the granular molecular sieve material.
The process described in this example may also be used, at suitably adjusted operating temperatures, for the re-moval of other~impurities i.e. undesirable gas ContaminantS from gas mixtures, e.g. H2S, NH3, benzene and methanol, to mention just a fewc For such cases, activated carbon powder or granular material may be used to good advantage instead of the molecular sieves.
EXAMPLE ~
Nickel carrier catalysts of the type described in Example 1~ contain among other impurities, nickel after they have been used for fat rendering. Befause of environmental pollution problems, this nickel content has been creating inCreaSing diffi-culties in the disposal of such wastes. Therefore a process iOS~;5'79 for recovering the nickel from the catalyst wastes is much sought after.
It has been found that it is possible to free the spent catalyst of nickel, after removal of the main fat quantities, by passing the material through a spiral conveyor reactor a few degrees below 100C, in counterflow to a CO gas stream. In the course ~of the reaction, carbonyl nickel is produced as an inter-mediate (unstable) compound, removed from the reactor by the circu-lating CO, and decomposed into nickel powder and CO at 180C.
In this way, the nicXel is recovered as a valuable material of high purity, and the carrier mass which leaves the spiral con-veyor at the bottom can be reused~
An additional class of processes in which use of the spiral conveyor or reactor is well suited, are catalytic gas treatment processes, in which regeneration of the catalyst is required after a predetermined reaction period. An example is the catalytic treatment of natural gas or petroleum deriva~ives which in many cases lead to pois~ning of the catalyst by sulfur content~ Continuous passage of the catalyst through the reactor permits its regeneration outside the reactor, with most economical utilization inside the reactor installation. T~is minimi~es the consumption of these usually expensive catalysts and thereby reduces the required investment of capital.
Other examples of the application of exchange processes in the spiral conveyor reactor of the invention are readily available to one skilled in the art. For instance, the drying _13-~L~S6579 of crystals and powders, in which the movement in the spiral conveyor counteracts the tendency of the crystals to agglomerate.
The roasting of sulfide materials is an example of the treatment of powdery solids with gases, in which the modification of the solid is the ob~ect of the process.
From these examples it is evident to one skilled in the art that the invention is particularly suitable for producing active metal powders with highly desirable characteristics~
Because of the wide applicability-of the process and apparatus, it is apparent that it is not the nature of the particular chemicals used but, the process of ope~ating the device of the invent~on and the device itself, which are the more important aspects of the invention.
Due to the fact that the powder grains are moved along by vibration, agglomeration is prevented. By increasing the amplitude of the vibration, even powder which does not flow easily can be treated. Because the gas is supplied in ex-cess, the equilibrium of the chemical reaction is displaced in favor of ~he end product and this reduces the residence time of the powder in the vibratory spiral conveyorO The impediments to diffusion which characterize previous known techniques, a~re considerably reduced by the mixing which is carried out in accordance with the invention by means of the mlxing ramp arrange-ments and by passing the reaction gas in counterflow manner~ Thus the heretofore customary residence times of a few hours can typically be reduced to a few minutes.
~056S7~
Because, in accordance with the invention, heat is supplied both from below by a heater arranaement positioned below the chute of the spiral conveyor, and from above (through radiation) and through convection by means of the reaction gas, very uniform heating of the powdery ~aterial is achieved. This also contributes appreciably to the uniformity of the end product achievable by means of the invention.
.
- , '', .
. - : . . ~
, ' : ~
:
, -`' ' ~
..
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. The method of processing a powdery material containing material capable of being a catalyst, utilizing a vibratory spiral conveyor which includes a spiral chute having its axis positioned generally vertically, a chamber enclosing the chute and means for producing axial vibration of the chute, the method comprising the steps of: introducing the powdery material at the top of the chute while causing the chute to reciprocate along its axis so as to cause the material to vibratingly move downward along the chute in a substantially uniform thickness layer; passing reaction gas in counterflow manner respective the powder so as to contact and react with the powder layer moving down the chute, the vibratory movement producing an alternating pump-ing and suction effect which improves the convective access of the gas to the powdery material and thereby the reaction; maintaining gas and powder tempera-tures appropriate for the reaction; removing the gaseous reaction products near the top of the spiral conveyor; and withdrawing the processed catalyst material near the bottom of the spiral conveyor.
2. The method of claim 1 further comprising intermixing the powder moving down the spiral conveyor chute.
3. The method of claim 2, wherein said intermixing comprises dividing the powder flow into plural superposed layers, and guiding said layers along said chute so that an initially lower layer becomes superposed upon an initially upper layer.
4. The method of claim 1, wherein said reaction gas is supplied in excess.
5. The method of claim 1, wherein the vibrating spiral conveyor is operated with such parameters that the powdery catalyst material has a dwell time of a few minutes in the conveyor.
6. The method of claim 1, wherein the catalyst powder is both calcined and reduced within the vibratory spiral conveyor.
7. The method of claim 1, wherein the powdery material introduced into the conveyor is [Cu(NH3)2] . (NH4)2 . (CrO4)2, the reaction gas is air heated to about 300°-350°C, and the conveyor is operated with such parameters that the material descends the chute in a substantially uniform layer of about 10-20mm thickness.
8. The method of claim 1, wherein the powdery material is Ni(OH)2 and the reaction gas is hydrogen at a temperature of about 350°-500°C, and the conveyor is operated with such parameters that the powder descends the chute in a substantially uniform layer of about 1-10mm thickness and a dwell time of about 5-10 minutes.
9. The method of claim 1, wherein the powdery material is a catalyst contaminated with nickel, and the reaction gas is CO at about 180°C.
10. Apparatus for carrying out a reaction between a powdery material and a gas, comprising a vibratory helical conveyor having a vertical or sub-stantially vertical axis and being enclosed in a gas-tight casing, the conveyor being provided with supply and discharge conduits for the gas,heating and/or cooling means provided under the helical turns of the conveyor, and mixing devices in or on the helical turns of the conveyor.
11. Apparatus according to claim 10, in which the mixing devices in or on the helical turns of the conveyor are provided in the form of reversing plates, each reversing plate having two planar surfaces formed by upper and lower plates inclined relatively to the floor of the helical turns of the con-veyor and in the direction of the movement of the powdery material along the helical turns, the upper plate dividing the powdery material into upper and lower layers, the upper layer being arrested by an upstanding wall on the upper plate so that the powdery material of the upper layer drops down through a space between the reversing plate and a side-wall of the conveyor on to the floor of the conveyor beneath the lower plate, and the powdery material of the lower layer drops over an edge of the lower plate onto the powdery material on the conveyor floor.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742403998 DE2403998C3 (en) | 1974-01-29 | Use of a gas-tight sheathed vibratory spiral conveyor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1056579A true CA1056579A (en) | 1979-06-19 |
Family
ID=5905884
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA218,828A Expired CA1056579A (en) | 1974-01-29 | 1975-01-28 | Powder-and-gas reactions |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS50108179A (en) |
| BR (1) | BR7500100A (en) |
| CA (1) | CA1056579A (en) |
| DK (1) | DK146314C (en) |
| IN (1) | IN143090B (en) |
| IT (1) | IT1030833B (en) |
| SE (1) | SE392043B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006053418A1 (en) * | 2004-11-19 | 2006-05-26 | Falconbridge Limited | Method for producing fine, low bulk density, metallic nickel powder |
| CN107073586A (en) * | 2014-07-02 | 2017-08-18 | 因温斯特技术公司 | Nickel metallic is manufactured |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5820198B2 (en) * | 2011-09-02 | 2015-11-24 | 東洋炭素株式会社 | Powder processing equipment |
-
1974
- 1974-11-15 SE SE7414372A patent/SE392043B/en unknown
- 1974-11-26 IT IT29820/74A patent/IT1030833B/en active
- 1974-12-12 DK DK647174A patent/DK146314C/en not_active IP Right Cessation
-
1975
- 1975-01-07 BR BR100/75A patent/BR7500100A/en unknown
- 1975-01-14 IN IN82/CAL/1975A patent/IN143090B/en unknown
- 1975-01-28 JP JP50011815A patent/JPS50108179A/ja active Pending
- 1975-01-28 CA CA218,828A patent/CA1056579A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006053418A1 (en) * | 2004-11-19 | 2006-05-26 | Falconbridge Limited | Method for producing fine, low bulk density, metallic nickel powder |
| CN107073586A (en) * | 2014-07-02 | 2017-08-18 | 因温斯特技术公司 | Nickel metallic is manufactured |
| US10537885B2 (en) | 2014-07-02 | 2020-01-21 | Invista North America S.A.R.L. | Nickel metal particle production |
| CN107073586B (en) * | 2014-07-02 | 2020-06-16 | 英威达纺织（英国）有限公司 | Nickel metal particle manufacture |
Also Published As
| Publication number | Publication date |
|---|---|
| DK146314B (en) | 1983-09-05 |
| SE7414372L (en) | |
| SE392043B (en) | 1977-03-14 |
| DK647174A (en) | 1975-10-13 |
| JPS50108179A (en) | 1975-08-26 |
| IN143090B (en) | 1977-10-01 |
| IT1030833B (en) | 1979-04-10 |
| DK146314C (en) | 1984-02-13 |
| BR7500100A (en) | 1975-11-04 |
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