Abstract: The present invention relates to a system (100) for dry sorption. The system comprises a gas inlet (130) through which exhaust gas from processing industry is flowing into the system (100), a velocity increasing device which is arranged downstream of the gas inlet (130), and a reaction chamber (140) is arranged downstream of the velocity increasing device. The exhaust gas is brought into contact with the sorbent from a sorbent distributor (150) in the reaction chamber (140), wherein the velocity increasing device is a booster (110) and comprises a plurality of resistances to the flow of gas for creation of a turbulent flow of exhaust gas at the outlet of the booster for enhanced sorption. Further, the present invention0relates to a method for cleaning exhaust gas from processing industry utilizing the system (100) for dry sorption.

Abstract: An aluminum production electrolytic cell comprises a bath with bath contents, at least one cathode electrode in contact with said contents, at least one anode electrode in contact with said contents, and a hood, defining interior area, covering at least a portion of said bath. The electrolytic cell is equipped for vent gases to be drawn from said interior area. The electrolytic cell also comprises at least one heat exchanger for cooling at least a portion of the vent gases drawn from interior area, prior to circulation thereof to interior area.

Abstract: A raw gas collection system for collecting raw gas from a plurality of aluminium smelting pots is equipped with a plurality of branch ducts, each of which is arranged to channel a respective branch flow of raw gas from an aluminium smelting pot to a collection duct, which is common to and shared by the branch ducts. Each of said branch ducts is, near an outlet thereof, equipped with a curved section for aligning the branch flow with a flow direction of raw gas already present in the common collection duct, and a constriction for accelerating the branch flow through the branch duct outlet into the common collection duct. Furthermore, each of said branch ducts is equipped with a heat exchanger for removing heat from the respective branch flow of raw gas. The combined flow resistance of the constriction and the heat exchanger reduces the need for adjusting the respective branch flows using dampers, thereby reducing the power required to transport the raw gas.

Abstract: An aluminium production electrolytic cell (4) comprises a bath (8) with bath contents (8a), at least one cathode electrode (10) in contact with said contents (8a), at least one anode electrode (6) in contact with said contents (8a), and a hood (16), defining interior area (16a), covering at least a portion of said bath (8). The electrolytic cell (4) is equipped for vent gases to be drawn from said interior area (16a). The electrolytic cell (4) also comprises at least one heat exchanger (52) for cooling at least a portion of the vent gases drawn from interior area (16a), prior to circulation thereof to interior area (16a).

Abstract: A gas cleaning unit for cleaning an effluent gas of at least one aluminium production electrolytic cell comprises a contact reactor in which the effluent gas is brought into contact with alumina, and a dust removal device for removing at least a portion of the alumina. The gas cleaning unit further comprises a wet scrubber in which the effluent gas is brought into contact with an absorption liquid containing water for removing further pollutants from the effluent gas. The wet scrubber is positioned at a point vertically higher than that of the dust removal device.

Abstract: A raw gas collection system for collecting raw gas from a plurality of aluminum smelting pots is equipped with a plurality of branch ducts (28d), each of which is arranged to channel a respective branch flow (38d) of raw gas from an aluminum smelting pot to a collection duct (26A), which is common to and shared by the branch ducts (28d). Each of said branch ducts (28d) is, near an outlet (52d) thereof, equipped with a curved section (50d) for aligning the branch flow (38d) with a flow direction of raw gas (27A) already present in the common collection duct (26A), and a constriction (54d) for accelerating the branch flow (38d) through the branch duct outlet (52d) into the common collection duct (26A). Furthermore, each of said branch ducts (28d) is equipped with a heat exchanger (40d) for removing heat from the respective branch flow (38d) of raw gas.

Abstract: A gas cleaning unit for cleaning an effluent gas of at least one aluminum production electrolytic cell comprises a contact reactor in which the effluent gas is brought into contact with alumina, and a dust removal device for removing at least a portion of the alumina. The gas cleaning unit further comprises a wet scrubber in which the effluent gas is brought into contact with an absorption liquid containing water for removing further pollutants from the effluent gas. The wet scrubber is positioned at a point vertically higher than that of the dust removal device.

Abstract: An aluminum production electrolytic cell (14) comprises a bath (20) with bath contents (18), at least one cathode electrode (22) in contact with said contents (18), at least one anode electrode (16) in contact with said contents (18), and a hood (36), defining interior area (36a), covering at least a portion of said bath (20). The electrolytic cell (14) is equipped for effluent gases to be drawn from said interior area (36a). The electrolytic cell (14) also comprises at least one heat exchanger (74) for cooling at least a portion of the gases drawn from interior area (36a), prior to circulation thereof to interior area (36a) through at least one distribution device (90).

Abstract: A raw gas collection system (15) for collecting raw gas from a plurality of aluminum smelting pots (4) is equipped with a plurality of branch ducts (16, 16a-d). Each branch duct (16, 16a-d) is arranged to channel a respective branch flow (32, 32a-b) of raw gas from an aluminum smelting pot (4) to a collecting duct (20a), which is common to and shared by branch ducts (16, 16a-d). Several of the branch ducts (16, 16a-d) are equipped with a combined heat transfer and flow resistance generating element (17) to remove heat from the respective branch flow (32, 32a-b) of raw gas and to balance the flow of raw gas in the raw gas collecting system (15). The combined heat transfer and flow resistance generating elements (17) reduce the need for adjusting the respective branch duct (16, 16a-d) flow volumes using dampers, thereby reducing the power required to transport the raw gas through the system.

Abstract: An improved flue gas cooler 10, or bank of coolers 10, handles flue gas G from aluminum reduction cells in an aluminum smelter plant. Each flue gas cooler 10 has a gas inlet chamber 14, a gas outlet chamber 16, and a matrix of gas cooling tubes 18 extending between the inlet chamber and the outlet chamber. Each cooling tube 18 has a bell-shaped inlet end 19 comprising an aerodynamically curved gas-accelerating profile effective to facilitate streamlined flow of flue gas G into the tube. The improved flue gas cooler makes it possible to connect the flue gas cooler to receive flue gas G direct from the aluminum reduction cells without getting clogged by dust and sublimates present in the flue gas.

Abstract: A metallurgical plant gas cleaning system (5) comprises at least one gas cleaning unit (28), and a gas flow generating device (22) for generating a flow of effluent gas to be cleaned through the gas cleaning unit (28). The gas cleaning system (5) further comprises a heat exchanger (26) for cooling said effluent gas and for generating a heated fluid, and a heated fluid-propelled drive unit (46) for receiving the heated fluid generated by said heat exchanger (26) to power said gas flow generating device (22).

Abstract: A gas cleaning unit for cleaning an effluent gas of at least one aluminium production electrolytic cell comprises a contact reactor in which the effluent gas is brought into contact with alumina, and a dust removal device for removing at least a portion of the alumina. The gas cleaning unit further comprises a wet scrubber in which the effluent gas is brought into contact with an absorption liquid containing water for removing further pollutants from the effluent gas. The wet scrubber is positioned at a point vertically higher than that of the dust removal device.

Abstract: An aluminium production electrolytic cell (14) comprises a bath (20) with bath contents (18), at least one cathode electrode (22) in contact with said contents (18), at least one anode electrode (16) in contact with said contents (18), and a hood (36), defining interior area (36a), covering at least a portion of said bath (20). The electrolytic cell (14) is equipped for effluent gases to be drawn from said interior area (36a). The electrolytic cell (14) also comprises at least one heat exchanger (74) for cooling at least a portion of the gases drawn from interior area (36a), prior to circulation thereof to interior area (36a) through at least one distribution device (90).

Abstract: A raw gas collection system for collecting raw gas from a plurality of aluminium smelting pots is equipped with a plurality of branch ducts (28d), each of which is arranged to channel a respective branch flow (38d) of raw gas from an aluminium smelting pot to a collection duct (26A), which is common to and shared by the branch ducts (28d). Each of said branch ducts (28d) is, near an outlet (52d) thereof, equipped with a curved section (50d) for aligning the branch flow (38d) with a flow direction of raw gas (27A) already present in the common collection duct (26A), and a constriction (54d) for accelerating the branch flow (38d) through the branch duct outlet (52d) into the common collection duct (26A). Furthermore, each of said branch ducts (28d) is equipped with a heat exchanger (40d) for removing heat from the respective branch flow (38d) of raw gas.

Abstract: A raw gas collection system (15) for collecting raw gas from a plurality of aluminium smelting pots (4) is equipped with a plurality of branch ducts (16, 16a-d). Each branch duct (16, 16a-d) is arranged to channel a respective branch flow (32, 32a-b) of raw gas from an aluminium smelting pot (4) to a collecting duct (20a), which is common to and shared by branch ducts (16, 16a-d). Several of the branch ducts (16, 16a-d) are equipped with a combined heat transfer and flow resistance generating element (17) to remove heat from the respective branch flow (32, 32a-b) of raw gas and to balance the flow of raw gas in the raw gas collecting system (15). The combined heat transfer and flow resistance generating elements (17) reduce the need for adjusting the respective branch duct (16, 16a-d) flow volumes using dampers, thereby reducing the power required to transport the raw gas through the system.

Abstract: An aluminium production electrolytic cell (4) comprises a bath (8) with bath contents (8a), at least one cathode electrode (10) in contact with said contents (8a), at least one anode electrode (6) in contact with said contents (8a), and a hood (16), defining interior area (16a), covering at least a portion of said bath (8). The electrolytic cell (4) is equipped for vent gases to be drawn from said interior area (16a). The electrolytic cell (4) also comprises at least one heat exchanger (52) for cooling at least a portion of the vent gases drawn from interior area (16a), prior to circulation thereof to interior area (16a).

Abstract: A gas cleaning system (1) is designed for removing hydrogen fluoride from a process gas generated during the production of aluminium from alumina. The gas cleaning system (1) comprises a scrubbing chamber (8, 10, 12) for purposes of mixing the process gas with particulate alumina, and a filter device (24,26,28) which is located downstream of the scrubbing chamber (8,10,12) with respect to the direction of flow of the process gas. A sulphur dioxide measurement device (40, 42, 44, 50) is operative for measuring the amount of the concentration of sulphur dioxide that is present in the process gas downstream of the filter device (24, 26, 28). A controller (46) is operative-connected to the sulphur dioxide measurement device (40, 42, 44, 50) and is operative for utilizing the measured amount of the concentration of sulphur dioxide for purposes of evaluating the efficiency of the hydrogen fluoride removal by the gas cleaning system (1).

Abstract: An improved flue gas cooler (10), or bank of coolers (10), handles flue gas G from aluminium reduction cells in an aluminium smelter plant. The or each flue gas cooler (10) has a gas inlet chamber (14), a gas outlet chamber (16), and a matrix of gas cooling tubes (18) extending between the inlet chamber and the outlet chamber. Each cooling tube (18) has a bell-shaped inlet end (19) comprising an aerodynamically curved gas-accelerating profile effective to facilitate streamlined flow of flue gas G into the tube. The improved flue gas cooler makes it possible to connect the flue gas cooler to receive hot raw flue gas G direct from the aluminium reduction cells without getting clogged by dust and sublimates present in the flue gas. Once cooled, the flue gas can be safely passed on to a flue gas cleaning plant of the dry scrubbing type.

Abstract: A decentralized cleaning plant for dry cleaning by removing fluorine containing waste gases from a reduction process in several electrolytic cells for aluminum, comprising: a storing place for aluminum oxide; a transportation system to distribute aluminum oxide from the storing place to the decentralized cleaning plant, a filter portion to store aluminum oxide before and after use in the decentralized cleaning plant; and an exhaust fan integrated with a top filter part of the plant, wherein a chimney and a separate silo are not required.

Abstract: The treatment, through a dry adsorption process, of a gas from a hot electrolytic process for aluminum production comprises at least two stages. Particulate aluminum oxide (the adsorbent) passes through the stages of the adsorption process countercurrently to the gas. Thus, the gas is treated with a partly spent adsorbent in a first dry adsorption stage, whereupon the particulate adsorbent is separated from the gas downstream from the first adsorption stage. Part of the separated particulate adsorbent is removed from the adsorption process for recycling adsorbed fluorine-containing substances to the electrolytic process. The remainder of the separated adsorbent is recirculated in the first adsorption stage in order to optimize the adsorption of fluorine-containing substances and the desorption of sulfur dioxide from the aluminum oxide in this stage. Simultaneously, the gas is transferred to a second dry adsorption stage.