Finely atomized alkaline sorbent salt solutions are injected into a hot flue gas stream to remove SO.sub.2. Flash evaporation of the droplets produces very fine dried sorbent particles, which react efficiently with SO.sub.2 in the flue gas. The liquid sorbent may be sodium carbonate, sodium hydroxide, sodium sulfite, potassium carbonate, potassium hydroxide or the like. In a coal-fired boiler, the liquid sorbent may be injected after the economizer section, where the flue gas temperature is below 850 F., and upstream of a particulate collection device. The dried sorbent particles react with SO.sub.2 and then are removed from the flue gas stream in the particulate collection device, producing a cleaned flue gas stream.

An exhaust gas processing system having excellent durability and good desulfurization and denitration efficiency is provided to efficiently recover carbon dioxide with high purity and reduced processing costs. The exhaust gas processing system has: a desulfurization unit removing sulfur oxides from the exhaust gas by the limestone-gypsum method; a denitration unit arranged downstream of the desulfurization unit to remove nitrogen oxides from the exhaust gas; a carbon dioxide recovery arranged downstream of the denitration unit to recover carbon dioxide from the exhaust gas; and an oxygen supply unit supplying to the desulfurization unit with a faction of the recovered gas from the carbon dioxide recovery unit as oxygen source. An analyzer is used to monitor the purity and recovery ratio of the carbon dioxide recovered, and the supplied ratio of recovered gas is adjusted, based on the monitored purity and recovery ratio.

The device for producing and treating a gas stream (F) includes an exchange enclosure (2) having at least a first discharge opening (2b) for a gas stream, means (3; 4) for supplying the enclosure with a liquid (L), means (3; 5) for discharging the liquid (L) contained in the exchange enclosure (2) and aeraulic means (6), which make it possible, during operation, to create, by means of suction or blowing, an incoming gas stream (F) coming from outside the exchange enclosure (2), so that said incoming gas stream (F) is introduced into the volume of liquid (V) contained in the exchange enclosure (2), and an outgoing gas stream (F), treated by direct contact with said volume of liquid, rises inside the exchange enclosure and is discharged out of the exchange enclosure (2) through the discharge opening (2b).

The present invention discloses a resource recovery method and a resource recovery system of desulfurized ash. The resource recovery method comprises: washing desulfurized ash with water, and performing solid-liquid separation to obtain solid residues rich in calcium sulfite and calcium sulfate and a solution rich in calcium hydroxide; preparing the solution into desulfurized slurry; and roasting the solid residues under the action of a reducing agent to obtain flue gas rich in sulfur dioxide and residues rich in calcium oxide. Therefore, the recovery of sulfur and calcium in the desulfurized ash is realized, and no solid waste, liquid waste, gas waste, etc. are produced in the process.

A system for treating a fluid used for cleaning exhaust gas from pollutants including particulate matter comprises a circulation tank for accommodating the fluid, the circulation tank comprising an outlet for bleeding off part of the fluid. A first device is provided for adding a first chemical to the part of the fluid, wherein the first chemical comprises a coagulant. A separation device receives a mixture comprising the part of the fluid and the first chemical, and separates the mixture into a first fraction and a second fraction, which first fraction contains more particulate matter than the second fraction. A flocculation arrangement comprising a first flocculator device is arranged between the separation device and the first device to retain the part of the fluid and the first chemical to promote agglomeration of particulate matter comprised in the part of the fluid before the mixture is received by the separation device.

The present application pertains to methods for making metal oxides and/or citric acid. In one embodiment, the application pertains to a process for producing calcium oxide, magnesium oxide, or both from a material comprising calcium and magnesium. The process may include reacting a material comprising calcium carbonate and magnesium carbonate. Separating, concentrating, and calcining may lead to the production of oxides such as calcium oxide or magnesium oxide. In other embodiments the application pertains to methods for producing an alkaline-earth oxide and a carboxylic acid from an alkaline earth cation-carboxylic acid anion salt. Such processes may include, for example, reacting an alkaline-earth cation-carboxylic acid anion salt with aqueous sulfur dioxide to produce aqueous alkaline-earth-bisulfite and aqueous carboxylic acid solution. Other useful steps may include desorbing, separating, and/or calcining.

Methods, apparatus, and compositions for cleaning gas. The use of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. The use of different oxidation potentials may reduce unwanted ammonia slip.

The present invention relates generally to the field of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.) and, in particular to a new and useful method and apparatus for: (i) reducing the levels of one or more gas phase selenium compounds and/or one or more other RCRA metals, or RCRA metal compounds (regardless of whether such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase); (ii) capturing, sequestering and/or controlling one or more gas phase selenium compound and/or one or more other RCRA metals, or RCRA metal compounds (regardless of whether such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase) in a flue gas stream and/or in one or more pieces of emission control technology; and/or (iii) capturing, sequestering and/or controlling one or more gas phase selenium compound and/or one or more other RCRA metals, or RCRA metal compounds (regardless of whether such other RCRA metals or RCRA metal compounds are in the gas phase or some other phase) in a flue gas stream prior to desulfurization and/or in one or more pieces of emission control technology prior to one or more desulfurization units.

The present disclosure relates to a wastewater flue evaporating device. An wastewater evaporation crystallizer is provided, including an evaporating tube inlet, an inlet flange, an inlet chamber, a pneumatic inlet baffle, an evaporating tube body, a pneumatic outlet baffle, an outlet chamber, an outlet flange, and an evaporating tube outlet which are successively coupled, where the evaporating tube inlet is connected to provide a gas pipeline; the gas pipeline is connected on a flue between an external denitration device and an air preheater; the evaporating tube outlet is communicated with an inlet flue of a dust collector; the evaporating tube body is provided with a wastewater nozzle; and the wastewater nozzle is communicated with a pretreated waste pipe. The present disclosure provides an efficient and energy-saving wastewater evaporation crystallizer which increases evaporation efficiency by bringing in a high-temperature gas at a front end of the air preheater.

The present invention relates generally to the field of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.) and, in particular to a new and useful method and apparatus for: (i) reducing halogen levels necessary to affect gas-phase mercury control; (ii) reducing or preventing the poisoning and/or contamination of an SCR catalyst; and/or (iii) controlling various emissions. In still another embodiment, the present invention relates to a method and apparatus for: (A) simultaneously reducing halogen levels necessary to affect gas-phase mercury control while achieving a reduction in the emission of mercury; and/or (B) reducing the amount of selenium contained in and/or emitted by one or more pieces of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.).