The disclosure provides seven integrated methods for the chemical sequestration of carbon dioxide (CO.sub.2), nitric oxide (NO), nitrogen dioxide (NO.sub.2) (collectively NO.sub.2, where x=1, 2) and sulfur dioxide (SO.sub.2) using closed loop technology. The methods recycle process reagents and mass balance consumable reagents that can be made using electrochemical separation of sodium chloride (NaCl) or potassium chloride (KCl). The technology applies to marine and terrestrial exhaust gas sources for CO.sub.2, NO.sub.x and SO.sub.2. The integrated technology combines compatible and green processes that capture and/or convert CO.sub.2, NO.sub.x and SO.sub.2 into compounds that enhance the environment, many with commercial value.

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 invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps: Step (1a): providing a potassium hydroxide or potassium carbonate solution for neutralizing acid forming components such as dissolving SO.sub.2 or H.sub.2S; Step (1b): providing an SO.sub.2 contacting solution, containing at least some potassium sulfite or potassium bisulfite or potassium thiosulfate; Step (2): providing SO.sub.2 gas; Step (3): reacting these to absorb the SO.sub.2 gas and to form an intermediate reaction mixture comprising potassium sulfite, or potassium bisulfite or a mixture thereof, and optionally recovering the potassium sulfite, or potassium bisulfite or a mixture thereof, and/or optionally using steps 4 and 5; Step (4): adding sulfur or sulfide containing compound containing sulfur having the oxidation state of 0, 2 or of between 0 and 2 to the reaction mixture and optionally potassium hydroxide or potassium carbonate, and reacting the mixture under suitable conditions to form potassium thiosulfate; and Step (5): recovering the potassium thiosulfate, and optionally concentrating the potassium thiosulfate.

Apparatus and methods for denitrification and desulfurization of and dust removal from an FCC tail gas by 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 as deducting 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.

Multiple environmental, economic, and ecological issues are linked to a limited number of chemicals such as carbon dioxide, sulphur dioxide, methane, nitrous oxide, methanol, formaldehyde and ethylene or disposal of some waste products from farming, transportation, and the beverage industry. Accordingly, the reduction of the impacts of these limited number of gases on the environment and/or ecology is beneficial. Accordingly, there are presented a range of application of methods, systems, and treatments which mitigate these impacts.

Preparation of aqueous slurries of calcium dihydroxide. Preparation of aqueous suspensions of calcium hydroxide.

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 oxidizing an ammonia desulfurization solution. The apparatus may include an oxidation air system. The apparatus may include an oxidation tank. The apparatus may include in the tank, a gas-liquid dispersion enhancer. The enhancer may include a sieve plate layer that includes a sieve plate. The sieve plate layer may be one of a plurality of sieve plate layers. The plurality may include two or three sieve plate layers. The apparatus may include an oxidation enhancing device mated to the tank. The oxidation enhancing device may include an acoustic wave generating device. The oxidation enhancing device includes an ultrasonic wave generating device. The ultrasonic generating device may be configured to provide a sound intensity in the range 12 to 40 Watts/Liter. The ultrasonic generating device may be configured to provide to a liquid sound intensity in the range 12 to 40 Watts/Liter.

Ultra-clean char and ultra-clean gaseous hydrocarbons are produced from a carbon-based feedstock to generate maximum efficiency uniform heat and/or electricity in a clean environmentally friendly process. The ultra-clean char and ultra-clean gaseous hydrocarbon streams are produced by pyrolizing organic matter, such as coal or pet coke or any other carbon-based material including land, sea, plastics and industrial waste. The pyrolized organic matter may be combusted in the presence of oxygen to produce heat, which can be used to generate electricity in a conventional boiler/generator system. Further, pyrolized organic matter can be combusted in the presence of carbon dioxide and further processed to produce various hydrocarbons. In other embodiments, the ultra-clean post-combustion ash may be subjected to an extraction process for capturing valuable rare earth elements.

A process for preparing sulfuric acid may involve melting elemental sulfur in a melting stage to give molten sulfur. Sulfuric acid is subsequently produced from the molten sulfur. Further, sulfur-containing offgases formed in the melting stage may be subjected to oxidation in a supplementary oxidation stage in which sulfur-containing components of the offgases are oxidized to sulfur dioxide. The process may further involve processing the sulfur dioxide to give at least one reaction product. The melting stage may be operated without emissions by processing all of the offgases from the melting stage. An apparatus may be employed for carrying out such a process.