The present invention relates to a process and a device for capturing SO2 present in gases which originate from cells for the industrial production of aluminium by igneous electrolysis carried out on a group of at least two rectors (21; 22, ..., 2n) passed through in parallel by a gas stream (3) and supplied with a sorption agent of pulverulent material type capable of adsorbing effluents present in the gas stream (3) by bringing the sorption agent into contact with the gas stream (3), said at least two reactors (21; 22, ..., 2n) having means (10) for collecting said sorption agent after it has come into contact with said gas stream (3), at least one of said reactors (21; 22, ..., 2n) having means (11) for discharging said sorption agent, after it has come into contact with said gas stream (3), towards means (16) for injection into at least one other of said reactors (21; 22, ..., 2n) and, between the discharge means (11) and the injection means (16), said sorption agent is desorbed of the SO2 that it has adsorbed by at least one step of coming into contact with the gas stream (3) before reaching said discharge means (11).
The invention relates to a process and device for treating anode butts (5), taken from cells for producing aluminium by melt electrolysis, by covering the anode butts (5) with alumina (8) that is able to capture fluorine, the process consisting in, as soon as the butt (5) has been removed from the electrolysis cell, submerging it in alumina (8) that has been melted beforehand in order to make the submersion easier, and in that the alumina is allowed to solidify after the submersion so that the butt is covered with solid alumina until it has made the transfer from the electrolysis cell to a station equipped with devices for extracting and treating fumes, especially a hot grinding station or a cooling station, so as to confine the part and limit emission of gaseous pollutants, especially fluorinated pollutants.
The method of confining the cell gases in a capped cell, at least one cap (18) of which is locally and temporarily removed, consists in blowing at least one jet of air from substantially one edge of the opening bounded by at least one removed cap (18), so as to form an air curtain (21) completely covering the opening and providing a dynamic pneumatic barrier effect between the cell gases (15) inside the cell (1) and the ambient atmosphere outside this cell. The confining device comprises at least one nozzle for blowing at least one air jet, capable of forming the air curtain (21), which is inclined as the caps (18) normally are, the nozzle being supported by at least one part of the cell (1) and/or of at least one cap (18), and at least one air or compressed-air supply source supplies this nozzle, in order to blow the air jet or jets for forming the air curtain (21).
The installation (1) comprises in each of the sleeves (20), connecting a cell to a collector (11) and defining an internal cavity (22) having a nominal passage cross section (S) that is identical for all the sleeves (20), an adjusting device (30, 130) with a moving part (36, 135) having a first position in which it locally limits the flow of the gases in the respective sleeve (20) at a first non-zero passage cross section (S1), and a second position in which it locally limits the flow of the gases in the respective sleeve (20) at a second passage cross section (S2) contained between the first passage cross section (S1) and the nominal passage cross section (S), and the first passage cross sections (S1) increase with the increase in the pressure drops between the gas-treatment centre (2) and the upstream end (21) of the respective sleeves (20), outside of the adjusting devices (30, 130).
B08B 15/00 - Précautions prises pour empêcher les crasses ou les fumées de s'échapper de la zone où elles sont produitesRamassage ou enlèvement des crasses ou des fumées de cette zone
F16K 1/22 - Soupapes ou clapets, c.-à-d. dispositifs obturateurs dont l'élément de fermeture possède au moins une composante du mouvement d'ouverture ou de fermeture perpendiculaire à la surface d'obturation à éléments de fermeture articulés à pivot comportant disque ou volet pivotant dont l'axe de rotation traverse le corps de soupape, p. ex. régulateurs à papillon
5.
METHOD AND DEVICE FOR HEAT EXCHANGER FOULING REMOVAL
The invention relates to a method for removing fouling from a heat exchanger (2) used to cool a gas loaded with dust and pollutants and originating from fused-salt electrolysis cells during aluminium production, in which the gas can travel through a flow circuit (1) comprising at least one heat exchanger (2) capable of cooling said gas (3) and distribution members (6, 7, 8) capable of moving inside the pipe (1). The invention is characterised in that it comprises a step in which the distribution members (6, 7, 8) are moved between a first position (6a, 7a, 8a) in which the gas (3) travels through the heat exchanger (2) in a first flow direction (S1) and a second position (6b, 7b, 8b) in which the gas (3) travels through the heat exchanger (2) in a second opposite flow direction (S2).
Method of defouling a heat exchanger used for cooling gases laden with dust and contaminants, originating notably from fused-salt electrolysis in the manufacture of aluminium; said heat exchanger comprising at least one tube through which there flows a heat-transfer fluid capable of cooling the gas; characterized in that the method comprises the following steps: - circulating gas through a main circuit during normal phases of operation (20), said heat exchanger being arranged in said main circuit, and - circulating gas through a circuit F that bypasses the heat exchanger during defouling phases (22).
The invention relates to a method and device for unclogging a heat exchanger (2a, 2b). Said device is used for cooling gas (3) that is laden with dust and pollutants coming in particular from igneous electrolytic cells during aluminum manufacture. Said heat exchanger (2a, 2b) comprises at least one tube in which a heat-transfer fluid, capable of cooling the gas (3), flows. Said device is characterized in that it includes at least one sealing member (8, 9) that is capable of reducing the surface of exchange between said heat exchanger (2a, 2b) and said gas (3) during phases for unclogging the heat exchanger (2a, 2b).
The invention relates to a method and system for treating (22) fumes and gas (15) produced by at least one igneous electrolytic cell (2) during the production of aluminium, the fumes and gas comprising carbon dioxide, dust and hydrogen fluoride, and the treatment system (22) comprising: a collection circuit (24) suitable for collecting at least one portion of the fumes and gas (15) produced by the electrolytic cell (2); and a system for cooling (32) the collected fumes and gas (15), characterised in that said system comprises, on the one hand, a treatment path (38) including a treatment unit (30) suitable for filtering the dust and eliminating at least one portion of the hydrogen fluoride and a capturing unit (50) suitable for capturing at least one portion of the carbon dioxide contained in the cooled fumes and gas (15), and on the other hand, a recycling path (40) suitable for recovering a portion of the cooled fumes and gas (15) and for injecting said fumes and gas back into the electrolytic cell (2) in order to increase the concentration of carbon dioxide in the fumes and gas captured by the capturing unit (50).
B01D 53/14 - Séparation de gaz ou de vapeursRécupération de vapeurs de solvants volatils dans les gazÉpuration chimique ou biologique des gaz résiduaires, p. ex. gaz d'échappement des moteurs à combustion, fumées, vapeurs, gaz de combustion ou aérosols par absorption
The invention relates to a collection device (6) capable of collecting the gases emitted by multiple aluminum electrolysis tanks, characterized in that it comprises at least one bypass loop (20) for a gas flow, connected, at each of the ends thereof, to the collection device (6), said bypass loop (20) being capable of passing through a medium, the temperature of which is lower than the temperature of the gas.
The invention relates to a system (40) and method for treating the fumes and gases (18, 29) generated by at least one igneous electrolysis tank (2) during the production of aluminum, the fumes and the gases (18, 29) comprising carbon dioxide, wherein the treatment system (40) includes a collecting device (46) capable of collecting at least a portion of the fumes and gases (18, 29) generated by the electrolysis tank (2), characterized in that the collecting device (46) is capable of collecting fumes and gases (18, 29) comprising at least 6 % of carbon dioxide, and in that the treatment system (30) includes a trapping unit (54) capable of trapping at least a portion of the carbon dioxide contained in the fumes and gases (18, 29).
The invention relates to a system (22) for recovering the energy released by at least one electrolysis tank (2), wherein the recovery system comprises a first heat exchange loop (28) through which a coolant flows, the first loop (26) including: a heat exchanger (36) through which the coolant flows; and a recovery unit (38) capable of recovering the heat of the coolant having passed through the heat exchanger (36); a primary collecting circuit (24) capable of collecting at least a portion of the fumes and gases generated by the electrolysis tank (2), the heat exchanger (36) being arranged outside and spaced apart from the electrolysis tank (2); wherein the fumes and gases collected by the primary circuit (24) pass through the heat exchanger (36) for heating the coolant.
n, 2′n) preferably with an ascending gas flow (3), are supplied in parallel with gas and with a chemical neutralization and/or sorption agent of the pulverulent material type capable of adsorbing effluents present in the gas flow by bringing the chemical neutralization and/or sorption agent in contact with the gas flow, the at least two reactors having elements (10) for collecting the chemical neutralization and/or sorption agent after contact with the gas flow. At least one of the two reactors has elements (11) for discharging the chemical neutralization and/or or sorption agent, after contact with the gas flow, these discharge elements being connected to the collecting elements, and members (7, 16) for injecting the chemical neutralization and/or sorption agent into at least one other of the at least two reactors.
The method of the invention is used for monitoring the state of a smoke duct (20-20') connecting each suction rail (11) of a baking furnace (FAC) (1) for carbonated blocks, of the rotating fire type and preferably with open chambers or covered chambers, to a smoke processing centre (CTF) (23) for purifying the baking smoke from the FAC (1), wherein said smoke is drawn through at least one suction rail (11) of the FAC (1) and collected in the smoke duct (20-20') feeding said smoke to the CTF (23), the method including at least the step of detecting a leak in the smoke duct (20-20') consisting of parasitic inlets of ambient air into said duct and/or at least the step of detecting a fire in said duct (20-20').
F27B 13/14 - Aménagement des dispositifs de commande, de surveillance, d'alarme ou des dispositfs similaires
F27D 21/04 - Aménagement des appareils indicateurs ou d'alarme
F17D 3/01 - Dispositions pour la surveillance ou la commande des opérations de fonctionnement pour commander, signaler ou surveiller le transfert d'un produit
F17D 5/00 - Protection ou surveillance des installations
F17D 5/02 - Prévention, interception ou localisation des pertes
14.
METHOD FOR OPTIMISING THE CONTROL OF A CENTRE FOR THE TREATMENT OF FUMES FROM A ROTARY FURNACE FOR BAKING CARBON BLOCKS
The invention relates to a method for controlling a fume treatment centre (FTC) (23), scrubbing the baking fumes from a rotary baking furnace (1), in which the fumes are drawn in through at least one suction manifold (11) of the baking furnace (1) and collected in a duct (20, 20') that conveys said fumes to the fume treatment centre (23). The fume treatment centre includes a tower (24) which sprays water into the fumes in order to cool same and a least one reactor (25) for the physico-chemical neutralisation of the fumes, comprising contact with a reagent powder, such as alumina, followed by filtering (36) of the loaded reagent and the fume dust and recycling in the reactor (25) of at least one fraction of the filtered reagent and mixing of same with fresh reagent. The method includes at least the following steps: the flow of water in the cooling tower (24) is adjusted and/or the flow and/or recycling rate of the reagent in the reactor (25) is adjusted as a function of at least one parameter indicating the level of pollution of the fumes at the inlet of the fume treatment centre (23). The invention can be used for baking carbon cathodes and anodes for aluminium electrolysis.
F27D 17/00 - Dispositions pour l'utilisation de la chaleur perdueDispositions pour l'utilisation ou pour l'élimination des gaz résiduaires
F27B 13/14 - Aménagement des dispositifs de commande, de surveillance, d'alarme ou des dispositfs similaires
B01D 53/10 - Séparation de gaz ou de vapeursRécupération de vapeurs de solvants volatils dans les gazÉpuration chimique ou biologique des gaz résiduaires, p. ex. gaz d'échappement des moteurs à combustion, fumées, vapeurs, gaz de combustion ou aérosols par adsorption, p. ex. chromatographie préparatoire en phase gazeuse avec adsorbants mobiles avec adsorbants dispersés
15.
GROUP OF AT LEAST TWO GAS-FLOW REACTORS SUPPLIED WITH CHEMICAL NEUTRALIZATION AND/OR SORPTION AGENT
The present invention relates to a group of at least two gas-flow reactors (21, 22, 2'2, ..., 2n, 2'n) preferably with an ascending gas flow (3), which are supplied on the one hand, in parallel, with gas and on the other hand with a chemical neutralization and/or sorption agent of the pulverulent material type that is capable of adsorbing effluents present in said gas flow (3) by bringing said chemical neutralization and/or sorption agent in contact with said gas flow (3), said at least two reactors (21, 22, 2'2, ..., 2n, 2'n) having means (10) for collecting said chemical neutralization and/or sorption agent after it has been brought into contact with said gas flow (3), characterized in that at least one of said two reactors (2l, 22, 2'2, ..., 2n, 2'n) has means (11) for discharging said chemical neutralization and/or or sorption agent, after having been brought into contact with said gas flow (3), said means (11) being connected to said collecting means (10), and means (7, 16) for injecting the chemical neutralization and/or sorption agent into at least one other of said at least two reactors (2l, 22, 2'2, ..., 2n, 2'n).
B01D 53/12 - Séparation de gaz ou de vapeursRécupération de vapeurs de solvants volatils dans les gazÉpuration chimique ou biologique des gaz résiduaires, p. ex. gaz d'échappement des moteurs à combustion, fumées, vapeurs, gaz de combustion ou aérosols par adsorption, p. ex. chromatographie préparatoire en phase gazeuse avec adsorbants mobiles avec adsorbants dispersés selon la technique de fluidisation
B01J 8/26 - Procédés chimiques ou physiques en général, conduits en présence de fluides et de particules solidesAppareillage pour de tels procédés les particules étant fluidisées selon la technique du "lit fluidisé" comportant au moins deux lits fluidisés, p. ex. installations de réaction et de régénération
16.
GROUP OF AT LEAST TWO GAS-FLOW REACTORS SUPPLIED WITH CHEMICAL NEUTRALIZATION AND/OR SORPTION AGENT
The present invention relates to a group of at least two gas-flow reactors (21, 22, 2'2, ..., 2n, 2'n) preferably with an ascending gas flow (3), which are supplied on the one hand, in parallel, with gas and on the other hand with a chemical neutralization and/or sorption agent of the pulverulent material type that is capable of adsorbing effluents present in said gas flow (3) by bringing said chemical neutralization and/or sorption agent in contact with said gas flow (3), said at least two reactors (21, 22, 2'2, ..., 2n, 2'n) having means (10) for collecting said chemical neutralization and/or sorption agent after it has been brought into contact with said gas flow (3), characterized in that at least one of said two reactors (2l, 22, 2'2, ..., 2n, 2'n) has means (11) for discharging said chemical neutralization and/or or sorption agent, after having been brought into contact with said gas flow (3), said means (11) being connected to said collecting means (10), and means (7, 16) for injecting the chemical neutralization and/or sorption agent into at least one other of said at least two reactors (2l, 22, 2'2, ..., 2n, 2'n).
B01D 53/12 - Séparation de gaz ou de vapeursRécupération de vapeurs de solvants volatils dans les gazÉpuration chimique ou biologique des gaz résiduaires, p. ex. gaz d'échappement des moteurs à combustion, fumées, vapeurs, gaz de combustion ou aérosols par adsorption, p. ex. chromatographie préparatoire en phase gazeuse avec adsorbants mobiles avec adsorbants dispersés selon la technique de fluidisation
B01J 8/26 - Procédés chimiques ou physiques en général, conduits en présence de fluides et de particules solidesAppareillage pour de tels procédés les particules étant fluidisées selon la technique du "lit fluidisé" comportant au moins deux lits fluidisés, p. ex. installations de réaction et de régénération
17.
METHOD AND DEVICE FOR PROCESSING GASEOUS WASTES IN PARTICULAR CONTAINING A HYDROFLUORIC ACID
The invention relates to a method for processing hydrofluoric acid-containing gaseous wastes (E) consisting (a) in capturing said gaseous wastes (E), (d) in processing said hydrofluoric acid-containing gaseous wastes (E) by means of an alumina powder (A) for fixing at least one part of hydrofluoric acid, (e) in separating the processed gaseous wastes (E) and the alumina powder loaded with the hydrofluoric acid (Af), (f) in recycling at least one part of said alumina powder loaded with the hydrofluoric acid (Af) at stage d) for processing said wastes (E), wherein said process is characterised in that the alumina powder which is loaded with the hydrofluoric acid (Af), obtainable by the separation (stage (e)) of is fresh of by the mixture thereof, is humidified prior to or during the introduction thereof into said processable gaseous wastes (E).
The invention relates to a method for processing and depolluting gaseous wastes containing volatile organic compounds (COV) and/or polycyclic aromatic hydrocarbons (HAP) by adsorption and/or condensation by powder mineral particles, consisting (c) in introducing powder alumna particles in a gaseous waste flow, wherein at least one part of the COV and / or HAP are deposited on the particles, (d) in separating the powder alumna particles loaded with the COV and / or HAP from the processed gaseous wastes. The inventive method is characterised in that (1), prior to the stage (c) for introducing the powder alumna particles, at least one stage for pre-cooling the treatable wastes in inserted, and (2) at the stage (c) for introducing the powder alumna particles, the used particles are cooled prior to the introduction thereof.
B01D 53/10 - Séparation de gaz ou de vapeursRécupération de vapeurs de solvants volatils dans les gazÉpuration chimique ou biologique des gaz résiduaires, p. ex. gaz d'échappement des moteurs à combustion, fumées, vapeurs, gaz de combustion ou aérosols par adsorption, p. ex. chromatographie préparatoire en phase gazeuse avec adsorbants mobiles avec adsorbants dispersés
brevets
