Disclosed herein are systems and methods for reducing the particulate matter content of an exhaust gas from a carbon black process.

Apparatus and methods for controlling aerosol production during absorption in ammonia desulfurization, by removing sulfur dioxide in flue gas with an absorption circulation liquid containing ammonium sulfite, so as to control the aerosol production during absorption in ammonia desulfurization. Efficient desulfurization and dust removal may be achieved by staged solution composition control and reaction condition control. At the same time ammonia escape and aerosol production during absorption may be controlled. The flue gas may be subjected to preliminary temperature lowering and purification, and may be allowed to contact with an absorption circulation liquid and a fine particle washing circulation liquid sequentially. Levels of solution compositions and reaction temperatures may be controlled.

Apparatus and methods for denitrification and desulfurization of and dust removal from an FCC tail gas by an ammonia-based process. The apparatus may include a first-stage waste heat recovery system, a denitrification system, a dust removal and desulfurization system, a tail gas exhaust system, and an ammonium sulfate post-processing system. The dust removal and desulfurization system may include a dedusting tower and an absorption tower disposed separately. The top and the bottom of the absorption tower may be connected respectively to the tail gas exhaust system and the ammonium sulfate post-processing system. The absorption tower may include sequentially, from bottom to top, an oxidation section, an absorption section, and a fine particulate control section. The methods may be implemented with the apparatus.

Apparatus and methods for denitrification and desulfurization of and dust removal from an FCC tail gas by an ammonia-based process. The apparatus may include a first-stage waste heat recovery system, a denitrification system, a dust removal and desulfurization system, a tail gas exhaust system, and an ammonium sulfate post-processing system. The dust removal and desulfurization system may include a dedusting tower and an absorption tower disposed separately. The top and the bottom of the absorption tower may be connected respectively to the tail gas exhaust system and the ammonium sulfate post-processing system. The absorption tower may include sequentially, from bottom to top, an oxidation section, an absorption section, and a fine particulate control section. The methods may be implemented with the apparatus.

A method for removing SO.sub.x from a gas by using a polyol composite solution is provided. The polyol composite solution is made by mixing a polyol with an organic acid and/or organic acid salt, the polyol composite solution is brought into contact with the gas containing SO.sub.x to absorb the SO.sub.x in the gas, wherein x=2 and/or 3, and the polyol refers to an organic compound other than ethylene glycol and polyethylene glycol, which contains simultaneously two or more than two hydroxyl groups in a same organic molecule.

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.

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.

A method for the reduction and prevention of mercury emissions into the environment from combusted fossil fuels or other off-gases with the use of peracetic acid is disclosed. The peracetic acid is used for the capture of mercury from the resulting flue gases using a flue gas desulfurization system or scrubber. The method uses peracetic acid in conjunction with a scrubber to capture mercury and lower its emission and/or re-emission with stack gases. The method allows the use of coal as a cleaner and environmentally friendlier fuel source as well as capturing mercury from other processing systems.

The description relates to a process for reducing acid plume from stacks from coal-fired combustors operating at varying loads, which have typically been treated by back-end calcium carbonate (limestone) which has not been able to effectively control visible acid plume as power is ramped up from low load. According to the process, as high sulfur and high iron coals are burned in a combustor, magnesium hydroxide slurry is introduced into hot combustion gases in or near the combustion zone. And, during ramp up to high load from a period of operation at low load, additional magnesium hydroxide is introduced into an intermediate-temperature zone.

Systems, apparatuses, and processes for controlling free ammonia in wet flue gas desulfurization processes in which an ammonia-containing scrubbing solution is used to produce ammonium sulfate. Such an apparatus includes an absorber having a contactor region through which a flue gas comprising sulfur dioxide is able to flow and a reaction tank containing a scrubbing solution containing ammonium sulfate. The tank has a sidewall and bottom wall that define the perimeter and bottom of the tank. Lance-agitator units are distributed around the perimeter of the tank, each having a lance that injects a mixture of oxygen and a dilute ammonia-containing fluid toward the bottom of the tank and an agitator that agitates the mixture and propels the mixture toward the bottom of the tank. The apparatus includes a source of the mixture of oxygen and dilute ammonia-containing fluid, and recirculates the scrubbing solution from the tank to the contactor region.