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AssigneeStamicarbon B.V.
InventorsBrian Sayre Higgins, John Marshall Tate, III, Robert Arthur Yates, Marcel Julien Pomerleau, Jon Michael Heon, Wilfried Marc Renaat Dirkx, Juan Coloma González
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Disclosed are methods and systems for removing submicron particles from a gas stream, in particular from urea prilling off-gas, wherein a Venturi ejector is used. A method comprises contacting a gas stream containing submicron particles in a Venturi ejector with an injected high velocity scrubbing liquid to provide a pumping action, wherein the scrubbing liquid has an initial velocity of at least 2 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m3/h)/(m3/h). The disclosure also pertains to a prilling tower having a gas stream treatment system comprising a Venturi ejector at the top of the prilling tower, and to a method of modifying an existing prilling tower.
A method for removing submicron particles from a gas stream containing submicron particles said stream being off-gas from urea finishing, the method comprising:
A gas stream treatment system, comprising two Venturi stages in series, wherein each of said Venturi stages comprises a horizontally placed Venturi ejector comprising a converging part, a throat, and a diverging tube part, and a nozzle for spraying into said throat, wherein said Venturi stages are placed above each other, and wherein each Venturi stage comprises a scrubbing liquid recirculation loop comprising a pump for pressurizing and recirculating scrubbing liquid to said nozzle, wherein the Venturi stages have separate recirculation loops, further comprising a sprayer between a first and a downstream second Venturi stage, for spraying an aqueous solution having a higher water concentration than the scrubbing liquid of the first Venturi stage.
A urea prilling tower having a gas stream treatment system at the top of the prilling tower, said gas stream treatment system comprising two Venturi stages in series, wherein each of said Venturi stages comprises a horizontally placed Venturi ejector comprising a converging part, a throat, and a diverging tube part, and a nozzle for spraying into said throat, wherein said Venturi stages are placed above each other, and wherein each Venturi stage comprises a scrubbing liquid recirculation loop comprising a pump for pressurizing and recirculating scrubbing liquid to said nozzle, wherein the Venturi stages have separate recirculation loops.
A natural draft urea prilling tower, having a gas stream treatment system at the top of the prilling tower, wherein the gas stream treatment system comprises at least two Venturi ejector scrubbers in series.
A method of modifying an existing prilling tower, comprising installing a the gas stream treatment system comprising two Venturi stages in series, wherein each of said Venturi stages comprises a horizontally placed Venturi ejector comprising a converging part, a throat, and a diverging tube part, and a nozzle for spraying into said throat, wherein said Venturi stages are placed above each other, and wherein each Venturi stage comprises a scrubbing liquid recirculation loop comprising a pump for pressurizing and recirculating scrubbing liquid to said nozzle, wherein the Venturi stages have separate recirculation loops on top of the prilling tower.
Dependencies are inferred from the claim text.