Abstract: Horizontal duct scrubbing systems for removing particulate matter from a gas are disclosed. The horizontal scrubbing systems may receive a particulate-containing gas stream (e.g., containing PM10 and/or PM2.5 particulate matter), and remove at least some of such particulates by spraying liquid droplets co-current to the flow of the gas stream, where the liquid droplets have a volume median droplet diameter (DV0.5) of from 240 microns to 600 microns. The scrubbing system may be substantially free of flow deflection members between a liquid inlet manifold and a demister. The system may be remove at least 50 wt. % PM10 and/or PM2.5 particulate matter from the gas stream.

Abstract: Horizontal duct scrubbing systems for removing particulate matter from a gas are disclosed. The horizontal scrubbing systems may receive a particulate-containing gas stream (e.g., containing PM10 and/or PM2.5 particulate matter), and remove at least some of such particulates by spraying liquid droplets co-current to the flow of the gas stream, where the liquid droplets have a volume median droplet diameter (DV0.5) of from 240 microns to 600 microns, The scrubbing system may be substantially free of flow deflection members between a liquid inlet manifold and a demister. The system may be remove at least 50 wt. % PM10 and/or PM2.5 particulate matter from the gas stream.

Abstract: Horizontal duct scrubbing systems for removing particulate matter from a gas are disclosed. The horizontal scrubbing systems may receive a particulate-containing gas stream (e.g., containing PM10 and/or PM2.5 particulate matter), and remove at least some of such particulates by spraying liquid droplets co-current to the flow of the gas stream, where the liquid droplets have a volume median droplet diameter (DV0.5) of from 240 microns to 600 microns. The scrubbing system may be substantially free of flow deflection members between a liquid inlet manifold and a demister. The system may be remove at least 50 wt. % PM10 and/or PM2.5 particulate matter from the gas stream.

Abstract: Horizontal duct scrubbing systems for removing particulate matter from a gas are disclosed. The horizontal scrubbing systems may receive a particulate-containing gas stream (e.g., containing PM10 and/or PM2.5 particulate matter), and remove at least some of such particulates by spraying liquid droplets co-current to the flow of the gas stream, where the liquid droplets have a volume median droplet diameter (DV0.5) of from 240 microns to 600 microns. The scrubbing system may be substantially free of flow deflection members between a liquid inlet manifold and a demister. The system may be remove at least 50 wt. % PM10 and/or PM2.5 particulate matter from the gas stream.

Abstract: Horizontal gas-liquid scrubbing systems and associated gas scrubbing methodologies are provided. In one embodiment, a horizontal duct scrubbing system includes a horizontally disposed housing having a waste gas inlet and a treated gas outlet, a liquid inlet manifold disposed within the horizontally disposed housing, the liquid inlet manifold comprising a plurality of nozzles oriented to spray a scrubbing liquor co-current to the flow of a gas stream flowing through the horizontally disposed housing, and a demister located proximal the treated gas outlet, where the horizontally disposed housing is substantially free of flow deflection members between the liquid inlet manifold and the demister.

Abstract: Horizontal gas-liquid scrubbing systems and associated gas scrubbing methodologies are provided. In one embodiment, a horizontal duct scrubbing system includes a horizontally disposed housing having a waste gas inlet and a treated gas outlet, a liquid inlet manifold disposed within the horizontally disposed housing, the liquid inlet manifold comprising a plurality of nozzles oriented to spray a scrubbing liquor co-current to the flow of a gas stream flowing through the horizontally disposed housing, and a demister located proximal the treated gas outlet, where the horizontally disposed housing is substantially free of flow deflection members between the liquid inlet manifold and the demister.

Abstract: Systems, methods and apparatus for restricting scale build-up in gas scrubbers and piping are disclosed. The scrubbers and/or pipes may have a coating disposed on internal surfaces thereof. The coating restricts formation of scale within the pipe, especially scale that would normally accumulate due to fluoride-enriched absorbents, such as fluoride-enriched alumina.

Abstract: Horizontal gas-liquid scrubbing systems and associated gas scrubbing methodologies are provided. In one embodiment, a horizontal duct scrubbing system includes a horizontally disposed housing having a waste gas inlet and a treated gas outlet, a liquid inlet manifold disposed within the horizontally disposed housing, the liquid inlet manifold comprising a plurality of nozzles oriented to spray a scrubbing liquor co-current to the flow of a gas stream flowing through the horizontally disposed housing, and a demister located proximal the treated gas outlet, where the horizontally disposed housing is substantially free of flow deflection members between the liquid inlet manifold and the demister. The gas stream may include sulfur dioxide, and the system may be capable of removing at least 71 vol. % sulfur dioxide from the gas stream.

Abstract: Methods and systems for controlling operating conditions of electrolytic cells are provided, particularly aluminum electrolytic cells. The method may includes the steps of measuring offgas temperature from the electrolytic cell, comparing the measured offgas temperature to a target offgas temperature, and completing a predetermined action in response to the comparing step. The predetermined action may include one or more of changing a feed rate of feed materials supplied to the electrolytic cell or inspecting a crust of the electrolytic cell for an undesired condition, such as a crust hole. The system may include an electrolytic cell adapted to contain a molten metal mixture, a hopper adapted to provide feed material to the electrolytic cell, a hood adapted to contain offgas from the electrolytic cell, an exhaust duct interconnected to the hood and containing a thermocouple for measuring offgas temperature, and a control panel for receiving temperature measurements from the thermocouple.

Abstract: Horizontal gas-liquid scrubbing systems and associated gas scrubbing methodologies are provided. In one embodiment, a horizontal duct scrubbing system includes a horizontally disposed housing having a waste gas inlet and a treated gas outlet, a liquid inlet manifold disposed within the horizontally disposed housing, the liquid inlet manifold comprising a plurality of nozzles oriented to spray a scrubbing liquor co-current to the flow of a gas stream flowing through the horizontally disposed housing, and a demister located proximal the treated gas outlet, where the horizontally disposed housing is substantially free of flow deflection members between the liquid inlet manifold and the demister. The gas stream may include sulfur dioxide, and the system may be capable of removing at least 71 vol. % sulfur dioxide from the gas stream.

Abstract: Systems, methods and apparatus for restricting scale build-up in gas scrubbers and piping are disclosed. The scrubbers and/or pipes may have a coating disposed on internal surfaces thereof. The coating restricts formation of scale within the pipe, especially scale that would normally accumulate due to fluoride-enriched absorbents, such as fluoride-enriched alumina.

Abstract: Horizontal gas-liquid scrubbing systems and associated gas scrubbing methodologies are provided. In one embodiment, a horizontal duct scrubbing system includes a horizontally disposed housing having a waste gas inlet and a treated gas outlet, a liquid inlet manifold disposed within the horizontally disposed housing, the liquid inlet manifold comprising a plurality of nozzles oriented to spray a scrubbing liquor co-current to the flow of a gas stream flowing through the horizontally disposed housing, and a demister located proximal the treated gas outlet, where the horizontally disposed housing is substantially free of flow deflection members between the liquid inlet manifold and the demister. The gas stream may include sulfur dioxide, and the system may be capable of removing at least 71 vol. % sulfur dioxide from the gas stream.

Abstract: A heat exchanger suitable for long term use in the unfiltered hot exhaust gas of an aluminum smelter is disclosed. In one embodiment, the heat exchanger comprises fluid carrying tubes connected together with web members to form a cylindrical shell. A header located at each end of the cylindrical shell is provided for feeding fluid to and from the tubes of the heat exchanger. Shrouds can be placed over the headers to affect hot gas turbulence and help minimize scaling. The surfaces of the cylindrical shell, when in un-scrubbed exhaust gas of an aluminum smelter, will be in contact with particles and/or dust and possibly caustic fumes and, therefore, may be treated with a relevant slip coating selected, for example, from the Teflon family.

Abstract: The present invention provides, a method of reducing fluoride emissions from aluminum smelting including the steps of providing alumina at a preselected feed rate to pots containing an aluminum producing molten electrolyte, wherein the aluminum producing molten electrolyte evolves gaseous fluoride byproducts; transporting the gaseous fluoride byproducts to alumina-based dry scrubbers, wherein the alumina scrubbers absorb at least a portion of the gaseous fluoride byproducts; determining the inlet temperature into the dry scrubber; and adjusting the alumina feed rate to the dry scrubber to optimize the capture efficiency of the gaseous fluoride byproducts, wherein adjusting the aluminum feed rate includes increasing the aluminum feed rate to correspond to a first temperature and decreasing the feed rate to correspond to a second temperature, wherein the first temperature is greater than the second temperature.