The present invention relates to a method for conditioning a soot-containing syngas stream in a single integrated apparatus containing a scrubbing vessel wherein particulate matter is decoupled from the waste water stream.

A process for purifying exhaust air from a granulation plant for producing a urea-containing granulate includes contacting a gas stream containing a urea-containing dust and ammonia with a sulfuric acid solution or a nitric acid solution in a scrubbing process. The scrubbing process involves scrubbing the gas stream with a first weakly acidic scrubbing solution in a first scrubbing stage and scrubbing the gas stream exiting the first scrubbing stage with a second scrubbing solution having a lower pH than the first weakly acidic scrubbing solution in a second scrubbing stage. The acidic scrubbing solution generated in the second scrubbing stage may be recycled into the first scrubbing stage via a conduit and used therein as the first weakly acidic scrubbing solution. A pre-scrubbing stage for scrubbing dust out of the gas stream may additionally be arranged upstream of the first scrubbing stage.

A process for purifying exhaust air from a granulation plant for producing a urea-containing granulate includes contacting a gas stream containing a urea-containing dust and ammonia with a sulfuric acid solution or a nitric acid solution in a scrubbing process. The scrubbing process involves scrubbing the gas stream with a first weakly acidic scrubbing solution in a first scrubbing stage and scrubbing the gas stream exiting the first scrubbing stage with a second scrubbing solution having a lower pH than the first weakly acidic scrubbing solution in a second scrubbing stage. The acidic scrubbing solution generated in the second scrubbing stage may be recycled into the first scrubbing stage via a conduit and used therein as the first weakly acidic scrubbing solution. A pre-scrubbing stage for scrubbing dust out of the gas stream may additionally be arranged upstream of the first scrubbing stage.

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 25 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m.sup.3/h)/(m.sup.3/h).

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 25 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m.sup.3/h)/(m.sup.3/h).

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 25 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m.sup.3/h)/(m.sup.3/h).

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 25 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m.sup.3/h)/(m.sup.3/h).

A scrubber for cleaning a gas comprises a casing extending along a longitudinal central axis and enclosing a scrubbing chamber. The casing has a gas inlet and a gas outlet. The casing is configured to permit flow of the gas through the scrubbing chamber in a flow direction from the gas inlet to the gas outlet. A deflector device in the scrubbing chamber between the gas inlet and outlet forms a gas passage between the deflector device and the casing. The deflector device comprises an upstream surface facing the gas inlet. A spraying nozzle is configured to spray a scrubbing liquid into the scrubbing chamber and the gas flow. A separation device comprises a shield element and is arranged between the upstream surface of the deflector device and the gas inlet. The shield element shields the upstream surface from the gas flow and is perforated by a plurality of holes.

A scrubber for cleaning of a gas comprises a casing, enclosing a scrubbing chamber. The casing comprises a gas inlet into and a gas outlet out from the scrubbing chamber. The casing permits the gas to flow through the scrubbing chamber from the gas inlet to the gas outlet. A deflector device is provided in the scrubbing chamber between the gas inlet and the gas outlet and forms a passage between the deflector device and the casing. The deflector device comprises a downstream surface facing the gas outlet and having an outer edge. A spraying nozzle is configured to spray a scrubbing liquid into the scrubbing chamber and the gas flow. A channel member extends from the deflector device. The channel member leads scrubbing liquid collected by the deflector device from the deflector device.

An active wet scrubbing filtration system for decontamination of a gas stream comprises components including one or more of: a) a vortexing apparatus which induces a contaminant-bearing gas into a helical flow; b) an initial scrubbing fluid spray section configured so as to project a spray of scrubbing fluid into the contaminant-bearing gas stream; c) an absorption structure; d) a condenser; and e) first and second scrubbing fluid decontamination systems that may be engaged or disengaged independently of each other. In some embodiments, the worksite comprises a clean room or one or more a semiconductor processing tools, which may include photolithography tools or photolithography tool clusters. In some embodiments, the active wet scrubbing filtration system may be useful in cleaning and recycling air or other process gasses for use in clean rooms or semiconductor processing tools.