Abstract: An apparatus and process for removing acidic gases and NOx from flue gases produced by utility and industrial plants. The process and apparatus convert NOx, and particularly nitric oxide, to nitrogen dioxide, which is then reacted to form a valuable byproduct. The process generally entails contacting a flue gas with a scrubbing medium to absorb acidic gases from flue gas and produce an intermediate flue gas. The intermediate flue gas is then cooled to cause nitric oxide present therein to be oxidized to form nitrogen dioxide, which is then absorbed from the flue gases to produce a nitrogen dioxide-containing solution and a scrubbed flue gas. The nitrogen dioxide in the nitrogen dioxide-containing solution is then reacted with ammonium hydroxide to form ammonium nitrate as a valuable byproduct.

Abstract: An apparatus and process for removing acidic gases, such as sulfur dioxide, hydrogen chloride and hydrogen fluoride, from flue gases produced by processing operations of the type carried out in utility and industrial plants. The apparatus is generally a gas-liquid contactor whose operation uses an ammonium sulfate-containing scrubbing solution to absorb acidic gases from flue gases, and into which oxygen and ammonia are then injected to react with the absorbed sulfur dioxide to produce ammonium sulfate as a valuable byproduct. The oxygen and ammonia are not introduced together into the scrubbing solution, but instead are introduced sequentially and in a manner so that the oxidation first occurs in a relatively low pH solution as a result of the absorbed acidic gases. The ammonia is then added to the solution in a manner that inhibits or prevents intermixing of the ammonia with the majority of the solution, but is present in the solution when recycled for further absorption of acidic gases.

Abstract: A method of producing calcium sulfate with a flue gas scrubbing facility having a gas-liquid contactor that uses a calcium-based slurry to absorb sulfur dioxide from a flue gas containing acidic gases, wherein a byproduct containing calcium sulfite precipitate is produced that is accumulated in a reservoir, such as a pond, apart from the gas-liquid contactor. Such a facility is modified to produce calcium sulfate by installing an acidifier vessel and an oxidation receptacle in series between a source of the flue gas and the gas-liquid contactor. The flue gas containing the acidic gases is caused to flow through the acidifier vessel, into which the byproduct is delivered from the reservoir so that some of the acidic gases of the flue gas are absorbed by the byproduct and the pH of the byproduct is sufficiently lowered to allow the calcium sulfite precipitate to dissolve in the byproduct.

Abstract: A wet flue gas desulfurization process for removing sulfur dioxide from flue gases. The process utilizes an ammonium sulfate scrubbing solution containing free dissolved ammonia as the reagent for the desulfurization process to produce ammonium sulfate as a valuable byproduct. The scrubbing solution contacts the flue gases and absorbs sulfur dioxide within an absorber of a flue gas scrubbing apparatus, and is then accumulated in a tank where the absorbed sulfur dioxide is reacted with oxygen and ammonia to produce ammonium sulfate. The scrubbing solution has a concentration of greater than 46% ammonium sulfate so as to have suspended solids of ammonium sulfate precipitate, preferably 1% to 20% suspended solids.

Abstract: A gas-liquid contactor is provided for removing gases and particulate matter from flue gases, such as those which are produced by processing operations of the type carried out in utility and industrial facilities. The gas-liquid contactor includes a tower into which a slurry is introduced for absorbing gases and particulate matter, and is configured so as to eliminate the requirement for a pump to deliver the slurry to the tower. In addition, the tower is configured to accommodate a maximum flue gas flow velocity through the tower while maintaining proper operation of the tower. Liquid particles in which the gases and particulate matter are entrained are collected in a tank, through which the slurry is recycled to the tower. The level of the slurry within the tank is higher than the entry point of the slurry into the tower, such that the slurry returns to the tower under the force of gravity.

Abstract: An apparatus and process for removing fine particles from sand and other particulate material. The apparatus is generally an air classifier (10) that combines gravitational and aerodynamic forces to classify sand at 10 mesh and finer. According to this invention, the classifier (10) is configured to have a vertical passage (16) centrally located at the vertical axis of an annular-shaped passage (12). The vertical passage (16) is defined by a plurality of inclined vanes (20) that are vertically separated by gaps (28). The sand or other particulate matter is introduced through an inlet (18) at or near the top of the annular-shaped passage (12), and then flows downwardly through the annular-shaped passage (12) around the vertical passage (16).

Abstract: A process is provided for removing sulfur dioxide out of gases by feeding the gases into a scrubber, where they are counter-currently contacted with a descending solution containing ammonium hydroxide and ammonium sulfate so that the sulfur dioxide is sorbed into the solution containing ammonium hydroxide and ammonium sulfate and a scrubbed gas is discharged from the scrubber. The sulfur dioxide-loaded solution is collected in a sump at the bottom of the scrubber, where a mixture of ammonia and air is injected into the sulfur dioxide loaded solution so that the ammonia reacts with the sulfur dioxide to produce ammonium sulfite which is (in turn) oxidized by the air into ammonium sulfate. The mixture of air and ammonia is injected into the solution in a direction that is towards the bottom of the sump so that portions of solution containing a higher pH and higher ammonium sulfite levels than the remainder of the solution is avoided, thereby minimizing ammonia slip out of the scrubber.

Abstract: A trailer mounts a first unit having an aggregate classifier and a pair of cyclones for pivotal movement between a generally horizontal storage position on the trailer and a generally vertical upright operational position on the trailer. A second unit having a second classifier and a second pair of cyclones is pivotally mounted on the trailer for movement between a generally horizontal storage position and a generally upright vertical operational position. In the storage positions, the units leave an open area in the middle of the trailer for storing and transporting ducts for use when operational. The duct work includes a riffle splitter "Y" duct for releasable securement to the aggregate inlets of the first and second classifiers in their upright position to provide a common aggregate inlet thereto. The ducts include a rectilinear duct for interconnecting the dust outlets of the cyclones when in their vertical operational position for channeling the dust to a baghouse.

Abstract: An flue gas scrubbing apparatus and process by which flue gases are contacted by a contact medium while traveling rapidly upward through a passage, such that the contact medium is fully entrained in the upward-flowing flue gases. The gases and the entrained contact medium are then redirected downwardly so that the entrained contact medium impacts the surface of a reservoir of the contact medium contained in the tank, with the result that much of the entrained contact medium is separated from the flue gases. The surface of the reservoir of contact medium causes the flue gases to abruptly change flow direction, flowing horizontally at a reduced velocity so that any remaining contact medium entrained in the gases becomes separated from the gases. After another abrupt change in flow direction, the gases are substantially free of contact medium and can be demisted by conventional means.

Abstract: A method for scrubbing flue gases utilizing a spray tower for removing acidic gases and particulate matter from flue gases produced by processing operations of the type carried out in utility and industrial facilities. The spray tower is equipped with a tank that serves as a reservoir for an alkaline slurry used to remove acidic gases and particulate matter from the flue gases. The slurry is pumped from the tank to spraying devices located within the tower. The spray tower further includes an internal structure that enables the slurry to be oxidized and gently agitated within a limited region of the tank, and without the requirement for two separate aeration and agitation devices. As a result, the construction, operational and maintenance costs of the spray tower are significantly reduced as compared to prior art spray towers.