Apparatus and methods for desulfurization of a sulfur-oxide containing gas by treatment with ammonia containing liquids. The apparatus and methods may utilize two distinct circuits of two different ammonia containing liquids which are applied in two distinct chambers. The gas may be cooled prior to entry into the circuits. There may be fluid communication between the two circulation circuits.

Apparatus and methods for desulfurization of a sulfur-oxide containing gas by treatment with ammonia containing liquids. The apparatus and methods may utilize two distinct circuits of two different ammonia containing liquids which are applied in two distinct chambers. The gas may be cooled prior to entry into the circuits. There may be fluid communication between the two circulation circuits.

A scrubbing solution for removing contaminants, including particularly hydrogen sulfide, from a fluid. The scrubbing solution includes at least one scrubbing reagent which has a primary or secondary amine and an acid, which may be phosphoric acid. The fluid being scrubbed is passed through the scrubbing solution. The contaminants react with the scrubbing reagent securing them in the scrubbing solution. The fluid being scrubbed and the scrubbing solution are then separated. The scrubbing solution is heated and, if the scrubbing solution is under pressure, the pressure is reduced. The acid facilitates thorough removal of the contaminants, and especially the hydrogen sulfide, from the scrubbing solution. The scrubbing solution is then ready for reuse. Because the scrubbing solution is rendered substantially free of hydrogen sulfides, it can absorb other sulfide contaminants that might not otherwise be absorbed.

A system and a method for industrial plant or utility plant flue gas desulfurization, with zero waste water liquid discharge from a wet flue gas desulfurization system utilized therein, are disclosed herein. The wet flue gas desulfurization system is supplied an absorption liquid for contact with a flue gas to absorb flue gas acid gases. Waste water from the wet flue gas desulfurization system is heated under pressure in a heat exchanger to produce heated waste water, which is supplied to a flash vessel to produce steam. The produced steam is supplied to the flue gas upstream of a particulate collection system and the wet flue gas desulfurization system, supplied to the flue gas upstream of the wet flue gas desulfurization system, or supplied to absorption liquid circulated to the wet flue gas desulfurization system.

Apparatus and methods for desulfurization of a sulfur-oxide containing gas by treatment with ammonia containing liquids. The apparatus and methods may utilize two distinct circuits of two different ammonia containing liquids which are applied in two distinct chambers. The gas may be cooled prior to entry into the circuits. There may be fluid communication between the two circulation circuits.

This invention relates to processes for selective removal of contaminants from effluent gases. A sulfur dioxide absorption/desorption process for selective removal and recovery of sulfur dioxide from effluent gases utilizes a buffered aqueous absorption solution comprising weak inorganic or organic acids or salts thereof, to selectively absorb sulfur dioxide from the effluent gas. Absorbed sulfur dioxide is subsequently stripped to regenerate the absorption solution and produce a sulfur dioxide-enriched gas. A process for simultaneous removal of sulfur dioxide and nitrogen oxides (NO.sub.x) from effluent gases and recovery of sulfur dioxide utilizes a buffered aqueous absorption solution including a metal chelate to absorb sulfur dioxide and NO.sub.x from the gas and subsequently reducing absorbed NO.sub.x to form nitrogen. A process to control sulfate salt contaminant concentration in the absorption solution involves partial crystallization and removal of sulfate salt crystals.

A system for capturing and monitoring atmospheric polluting agents (1). Includes a protection skeleton (100) that covers and protects the entire system; a power supply module (200), which has the purpose of providing electrical energy to the system; a bioremediation module (300) that captures and bioremediates the polluted gaseous streams that circulate inside it; a control and monitoring module (400), which census and modifies the operation parameters in real time. Finally, at least one particle capture unit (500) that gathers the particles that approach the system. This invention intends to boost the restoration of polluted gaseous streams with a certain concentration of some substance that could represent a risk for the health of the people, namely: CO, CO.sub.2, NOX, SOX, among others, so as the capture of particulate matter 10 (pm 10) and 2 (pm 2). This invention intends to avoid their spread, as well as the damage they cause to the health.

The present invention provides a method for recycling sulfuric acid from various industries. The recovery system is constructed that it can process spent acid containing H.sub.2O.sub.2 and recover waste heat to save energy. The heat from the spent acid recovery process is used to generate electric energy, hot water, and chilled water to reduce its energy consumption, operating cost, and carbon emissions. This system can produce electronic-grade and industrial-grade sulfuric acid at the same time and solve the problem of spent acid disposal from various industries.

A method for treating a flue gas, comprising: step (A) desulfurizing a flue gas to obtain a desulfurized flue gas, comprising NO.sub.x, SO.sub.x, and CO.sub.2; step (B) providing oxygen for an oxidization to obtain an oxidized flue gas; step (C) rinsing the oxidized flue gas with water to obtain a rinsed flue gas and a nitric acid solution; and step (D) contacting the rinsed flue gas with a basic solution to absorb the CO.sub.2 in the rinsed flue gas. The method for treating a flue gas can largely reduce the content of CO.sub.2 and NO.sub.x in the flue gas. Besides, the obtained product can be used as a carbon source and nitrogen source for algae cultivation.

A combustible gas from carbon black production is utilized in a gas engine by adding an oxygen-containing gas to the combustible gas, passing said mixed gas over a selective catalyst, which is active for oxidizing H.sub.2S to SO.sub.2 but substantially inactive for oxidation of CO, H.sub.2 and other hydrocarbons with less than 4 C-atoms, passing the converted gas through an SO.sub.2 removal step, and passing the cleaned gas to a gas engine or to an energy recovery boiler. This way, the tail gas from carbon black production, which is normally combusted in a CO boiler or incinerated, can be utilized to good effect.