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.

A new integrated method to capture polluted CO.sub.2 using CaO produced from phosphogypsum calcination using sulfur as non-CO.sub.2 fuel where (1) both pollutants of phosphogypsum and CO.sub.2 are transformed into environmentally neutral or useful products such as limestone or clinker and sulfuric acid; (2) low-CO.sub.2 CaO produced from calcination of phosphogypsum with sulfur as fuel can be used to produce low-CO.sub.2 clinker that replaces the use of high-CO.sub.2 limestone as raw material; (3) the use of sulfur as fuel to calcine phosphogypsum allows the production of low-cost sulfuric acid.

A process for the treatment of waste water, spent air, and hydrocarbon containing liquid and gaseous streams in the cumene/phenol complex is described. Various effluent streams are combined in appropriate collection vessels, including a spent air knockout drum, a hydrocarbon buffer vessel, a fuel gas knockout drum, a phenolic water vessel, and a non-phenolic water vessel. Streams from these vessels are sent to a thermal oxidation system.

A method (200) for desulfurization of a flue gas in a desulfurization unit of an industrial plant, includes receiving (202) a plurality of baseline parameters corresponding to the desulfurization unit of the industrial plant. The method further includes measuring (204), using a stack sensor, an emission value of sulfur oxides in the flue gas. The method also includes estimating (208), using a controller, a desirable value of a slurry parameter for desulfurization of the flue gas based on the measured emission value of the sulfur oxides. The method further includes determining (208), using the controller, at least one desulfurization parameter based on the desirable value of the slurry parameter. The method also includes controlling (210), using the controller, operation of the desulfurization unit based on the at least one desulfurization parameter to modify consumption of at least one of a slurry and an auxiliary power in the industrial plant.

A new integrated method to capture polluted CO.sub.2 using CaO produced from phosphogypsum calcination using sulfur as non-CO.sub.2 fuel where (1) both pollutants of phosphogypsum and CO.sub.2 are transformed into environmentally neutral or useful products such as limestone or clinker and sulfuric acid; (2) low-CO.sub.2 CaO produced from calcination of phosphogypsum with sulfur as fuel can be used to produce low-CO.sub.2 clinker that replaces the use of high-CO.sub.2 limestone as raw material; (3) the use of sulfur as fuel to calcine phosphogypsum allows the production of low-cost sulfuric acid.

A carbon dioxide recovery system for collecting carbon dioxide from an exhaust gas generated in a facility including a combustion device includes: a first exhaust gas passage through which the exhaust gas containing carbon dioxide flows; a fuel cell including an anode, a cathode disposed on the first exhaust gas passage so that the exhaust gas from the first exhaust gas passage is supplied to the cathode, and an electrolyte transferring, from the cathode to the anode, a carbonate ion derived from carbon dioxide contained in the exhaust gas from the first exhaust gas passage; and a second exhaust gas passage diverging from the first exhaust gas passage upstream of the cathode so as to bypass the cathode. A part of the exhaust gas is introduced to the second exhaust gas passage.

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 NOR, 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, NOx and SO.sub.2. The integrated technology combines compatible and green processes that capture and/or convert CO.sub.2, NOx and SO.sub.2 into compounds that enhance the environment, many with commercial value.

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.

A carbon dioxide recovery system includes: a first heat exchanger that is disposed between a boiler and a desulfurization device, cools exhaust gas g flowing from the boiler to the desulfurization device, and heats a first heat medium w1; and a carbon dioxide recovery device that, when supplied with heat of the first heat medium w1, separates and recovers carbon dioxide from an absorber having absorbed the carbon dioxide.

The present invention relates to a process for clean sailing of marine ship, comprising steps of: a) scrubbing exhaust gas of engine with seawater to generate scrubbing seawater; b) disposing of the scrubbing seawater in an open loop operation mode, including neutralizing the scrubbing seawater in an open loop operation mode; and/or c) disposing of the scrubbing seawater in a closed loop operation mode, including: i) storing the scrubbing seawater in a storage container; and ii) neutralizing the scrubbing seawater in a closed loop operation mode. The present invention also relates to a ship. The purpose of the present invention is to maintain the unique advantages of economy and environmental protection of marine ships to fulfill the global regulations of the United Nations on ship sulfur limit while safe sailing is ensured.