A device for waste gas scrubbing in a urea plant may be configured such that a waste gas passes along a transportation direction in the duct. The duct may include a first region for removing urea dust particles from the waste gas and a second region for removing chemical compounds from the waste gas, which can be integrated by an acid-base reaction into an aqueous liquid phase. A cross-sectional area of the duct extending perpendicular to the transportation direction in the second region may be greater than a cross-sectional area extending perpendicular to the transportation direction in the first region. Further, the device may be configured such that the duct extends horizontally at least in sections and/or the transportation direction of the waste gas through the duct extends horizontally in an installed state.

The invention relates to a process for the production of urea ammonium nitrate, a system and a method of modifying a plant. The process comprises subjecting ammonia-containing off-gas resulting from the production of ammonium nitrate (AN off-gas) to condensation under acidic conditions so as to form an acidic condensate, and using at least part of the acidic condensate as an acidic scrubbing liquid in a finishing treatment section having a gas inlet in fluid communication with a gas outlet of a finishing section of a urea production unit, wherein the finishing section is adapted to solidify urea liquid, and wherein said finishing treatment section is adapted to subject ammonia-containing off-gas of the finishing section to treatment with an acidic scrubbing liquid.

A method of desulfurizing a liquid hydrocarbon comprises providing an initial processing unit and an end processing unit, the initial processing unit having an initial reactor assembly and an initial sorption system, the end processing unit having an end reactor assembly, a separator and an end sorption system. The method further comprises feeding a liquid hydrocarbon having a sulfur content into the initial reactor assembly, feeding an aqueous feed into the initial reactor assembly, shear mixing the liquid hydrocarbon and the aqueous feed within the initial reactor assembly, to, in turn, react the aqueous feed with the sulfur content of the liquid hydrocarbon, and directing the liquid hydrocarbon and aqueous feed to the initial sorption system. The method even further comprises feeding a sorbent into the initial sorption system and adsorbing at least some of the sulfur content that has reacted with the aqueous feed from the liquid hydrocarbon.

A process and system are disclosed for capturing carbon dioxide from a gas stream. The process and system comprise a first stage, in which a metal silicate is reacted with nitric acid to produce a metal nitrate. The metal silicate can be one or more of: an alkaline-earth metal silicate, in particular magnesium or calcium; or an alkali metal silicate, in particular lithium. The process and system also comprise a second stage, in which the metal nitrate from the first stage is heated to a temperature sufficient to decompose the metal nitrate to a metal oxide. The process and system further comprise a third stage, in which the metal oxide is mixed with water to convert the metal oxide to a metal hydroxide solution. The process and system additionally comprise a fourth stage, in which the gas stream is scrubbed with the solution from the third stage such that the metal hydroxide reacts with the carbon dioxide to form a metal carbonate/bicarbonate product.

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).

A process is disclosed for removing nitrous components from a raw liquid nitric acid stream to produce a bleached nitric acid product (55). The raw liquid nitric acid stream (37) is from an absorber (19) of a nitric acid process. The process comprises contacting the raw nitric acid liquid stream with an oxidising gas (12) in a bleaching stage (52). At least some of the gas effluent (12c) from the bleaching stage enters (12d) a combustion stage (15) of the nitric acid process. The oxidising gas (12) entering the bleaching stage (52) may comprise at least about one-third of an oxidising gas feed (12) to the nitric acid process. At least about one-tenth of the bleaching stage gas effluent (12c) may enter (12d) the combustion stage (15).

An engine is operated to produce exhaust emissions containing carbon nano soot therein which are injected into a solubilizing tank containing nitic acid and carbonic acid in a water solution for solubilizing the carbon nano soot as carbon nano tubes. A gas flow exiting the tank is captured such that some water and some solubilized carbon nano tubes are carried with the gas flow for subsequent delivery to a plant growing medium, either directly or by storing the water and solubilized carbon nano tubes carried with the gas flow in a tank for subsequent application. The solubilizing tank may be supported on agricultural seeding implements or sprayer implements for direct application to crop covered ground. In an irrigation system, the gas flow from the solubilizing tank is directed towards a condensing tank for subsequent application of the condensate to a plant growing medium with irrigation water.

A device for waste gas scrubbing in a urea plant may be configured such that a waste gas passes along a transportation direction in the duct. The duct may include a first region for removing urea dust particles from the waste gas and a second region for removing chemical compounds from the waste gas, which can be integrated by an acid-base reaction into an aqueous liquid phase. A cross-sectional area of the duct extending perpendicular to the transportation direction in the second region may be greater than a cross-sectional area extending perpendicular to the transportation direction in the first region. Further, the device may be configured such that the duct extends horizontally at least in sections and/or the transportation direction of the waste gas through the duct extends horizontally in an installed state.