Disclosed is a method for the removal of soluble particulate matter from a gas stream, such as urea dust from the off-gas of a finishing section of a urea production plant. The method comprises subjecting the off-gas to at least two quenching stages an aqueous quenching liquid. The quenching liquid used in a first, upstream quench stage, is allowed to have a higher concentration of dissolved particulate matter than the quenching liquid in the second, downstream quench stage. The quenched gas is led through a particle capture zone, typically comprising one or more of a wet scrubber, a Venturi scrubber, and a wet electrostatic precipitator.

A semiconductor waste abatement system for a semiconductor processing system includes a vacuum pump, an abatement apparatus having an abatement chamber in fluid communication with a source of semiconductor waste gas from the semiconductor processing chamber, and with the abatement chamber configured to ionize the waste gas and to exhaust ionized gas. The abatement system further includes a filter apparatus with a filter chamber, which forms a liquid reservoir. The inlet of the filter apparatus is in fluid communication with the outlet of the abatement chamber and the liquid reservoir, and the outlet of the filter apparatus is in communication with the inlet of the vacuum pump, wherein the filter chamber is under a vacuum, and wherein semiconductor waste gas is ionized in the abatement chamber and then filtered by the filter apparatus prior to input to the vacuum pump.

Methods and compositions are described that remove chlorine from a chlorine-containing gas stream. The method includes adding a carbonate salt and optionally a scale inhibitor to a scrubbing liquid in a wet scrubbing system, and contacting the chlorine-containing gas with the scrubbing liquid. The amount of carbonate salt that is added can vary depending on the pH of the scrubbing liquid.

A process for recovering catalyst from a fluidized catalytic reactor effluent is disclosed comprising reacting a reactant stream by contact with a stream of fluidized catalyst to provide a vaporous reactor effluent stream comprising catalyst and products. The vaporous reactor effluent stream is contacted with a liquid coolant stream to cool it and transfer the catalyst into the liquid coolant stream. A catalyst lean vaporous reactor effluent stream is separated from a catalyst rich liquid coolant stream. A return catalyst stream is separated from the catalyst rich liquid coolant stream to provide a catalyst lean liquid coolant stream, and the return catalyst stream is transported back to said reacting step.

An improved air scrubber has an improved, more efficient, more robust impeller and impeller housing for mixing incoming air with water, scrubbing the air with increased efficiency and lower mean time between failures. Also water flow through the system is improved to prevent loss of scrubbing performance and to reduce user workload. In addition to these improvements, the water intake system has been redesigned to use less water, prevent using too much water, and to prevent previously common errors that require users to drain water from the impeller housing.

The device (1) for bringing a gas and a liquid into contact includes an enclosure (E), first means (5) for introducing into the enclosure and circulating therein a gas stream (G), second means (6) for introducing into the enclosure and circulating therein a liquid stream (L) that circulates inside the enclosure (E) in the same direction as the gas stream (G), and means (4A) for mixing the gas stream (G) and the liquid stream (L). These mixing means (4A) are positioned inside the enclosure (E) in the path of the gas stream and liquid stream and are capable of locally deflecting upward, and/or of locally causing to rise, at least one portion of the gas stream and liquid stream, so as to locally create turbulences in the gas stream and in the liquid stream.

An exhaust gas cleaning system comprises a first sub system including a scrubber unit comprising a scrubber arranged to wash the exhaust gas with a scrubber fluid, and a centrifugal separator arranged in communication with the scrubber unit for receiving the scrubber fluid after washing and separate it into a first and a second fraction, which second fraction is more polluted than the first fraction. The exhaust gas cleaning system further comprises a second sub system including a membrane filter arranged in communication with the centrifugal separator for receiving the first fraction output from the centrifugal separator and separating it into a third and a fourth fraction, which fourth fraction is more polluted than the third fraction. A method for cleaning exhaust gas onboard a ship involves cleaning an exhaust gas onboard a ship.

A method for processing a chemical stream includes contacting a feed stream with a catalyst in an upstream reactor section of a reactor having the upstream reactor section and a downstream reactor section, passing an intermediate product stream to the downstream reactor section, and introducing a riser quench fluid into the downstream reactor section, upstream reactor section, or transition section and into contact with the intermediate product stream and the catalyst to slow or stop the reaction. The method includes separating at least a portion of the catalyst from the product stream, passing the product stream to a product processing section, cooling the product stream, and separating a portion of the riser quench fluid from the product stream. The riser quench fluid separated from the product stream may be recycled back to the downstream reactor section, upstream reactor section, or transition section as the riser quench fluid.

Methods and compositions are described that remove chlorine from a chlorine-containing gas stream. The method includes adding a carbonate salt and optionally a scale inhibitor to a scrubbing liquid in a wet scrubbing system, and contacting the chlorine-containing gas with the scrubbing liquid. The amount of carbonate salt that is added can vary depending on the pH of the scrubbing liquid.

An air purification device includes a reactor having a hollow shape and extending in one direction, a discharge plasma generator comprising a first electrode disposed on an outer wall of the reactor and a second electrode disposed inside the reactor, where the discharge plasma generator is configured to generate a discharge plasma in a discharge region, a plurality of dielectric particles disposed on a packed-bed of the reactor, a liquid supplier which supplies a liquid into the reactor, and a liquid recoverer which recovers the liquid discharged from the reactor.