The invention describes a process for producing sulfuric acid by catalytic oxidation of SO.sub.2 to SO.sub.3 and subsequent absorption of the SO.sub.3 in sulfuric acid, wherein the SO.sub.3 is introduced into a first absorption stage (primary absorber) and at least partly absorbed there in concentrated sulfuric acid, wherein the SO.sub.3 not absorbed in the first absorption stage is supplied to a second absorption stage (secondary absorber) for the further absorption in concentrated sulfuric acid, and wherein the sulfuric acid is cooled after passing through the two absorption stages. The cooling of the sulfuric acid is effected in at least two heat exchangers connected in parallel, wherein one of the at least two heat exchangers is operated as partial evaporator and is cooled with boiler feed water/steam and the other one is cooled with cooling water and operated as pure acid cooler.

A solvent system for the removal of acid gases from mixed gas streams is provided. Also provided is a process for removing acid gases from mixed gas streams using the disclosed solvent systems. The solvent systems may be utilized within a gas processing system.

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) and, in particular to a new and useful method and apparatus designed to improve the water supplied to non-calcium-based, aqueous wet SO.sub.x scrubbers. In another embodiment, the present invention relates to a system and method for softening water for use in non-calcium-based, aqueous wet SO.sub.x scrubbers.

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 desulfurization and denitration agent which is a mixture of polyalcohol and/or polyglycol substances, polycarboxylic acid substances and alkaline substances heated to above 90 C. and yielding, after condensation and/or polymerization, macromolecular or high-polymer ethers and/or esters for use in removing sulfur dioxides and/or nitrogen oxides from gases.

A control device for a scrubber includes a converter which calculates a minimum amount of seawater: a minimum amount of seawater necessary for an absorption reaction of the sulfur oxide by the seawater, from an engine output and a sulfur content of fuel oil; another converter which calculates a corrected amount of seawater: an amount of seawater at which the sulfur oxide in the exhaust gas discharged from the scrubber is equal to or less than a set value; a summing element which calculates a set amount of seawater by summing the minimum amount and corrected amount of seawater; a pump control device which implements control such that seawater corresponding to the set amount is supplied to the scrubber; and an alkalinity setting device which sets the alkalinity of the seawater in accordance with traveled waters. The amount of seawater supplied to the scrubber is adjusted based on the alkalinity.

Coal-derived mineral matter is used to capture or remove combustion gas emissions from flue gas or exhaust gas. The coal-derived mineral matter may be obtained by separating it from coal particles, such as by use of a flotation separation process. Coal-derived mineral matter may also be present in fine coal refuse. In the method of removing combustion gas emissions from flue gas, an aqueous suspension of coal-derived mineral matter particles is contacted with the combustion gas emissions for sufficient time to cause the combustion gas emissions to react with the aqueous suspension and form an enhanced aqueous suspension. The combustion gas emissions may comprise NOx, SOx, CO, or mixtures thereof. An aqueous suspension of coal-derived mineral matter particles containing enhanced amounts of soluble and insoluble sulfate, sulfite, nitrate, nitrite, or carbonate reaction compounds formed by reaction of the aqueous suspension of the coal-derived mineral matter particles with combustion gas emissions.

An air pollution control unit is configured to bring particle-containing gas and washing liquid into contact with each other to collect particles in the particle-containing gas. The air pollution control unit includes a gas washing column having a gas cleaning section in which the particle-containing gas and the washing liquid are brought into co-current contact with each other, a gas cooling column disposed downstream of the gas washing column along the gas flow and having a gas cooling section in which the particle-containing gas that has been cleaned (cleaned gas) and cooling liquid are brought into countercurrent contact with each other, and a gas communication path.

Improved methods and systems are provided for the on-board removal of sulfur dioxide generated by a marine vessel. The method includes spraying an alkaline fluid into the flue gas to produce a saturated flue gas stream containing the alkaline fluid; and flowing the saturated flue gas stream containing the alkaline fluid through a venturi to cause the particulates in the flue gas to impact the alkaline fluid and react at least a portion of the sulfur dioxide with the alkaline fluid.

A solvent system for the removal of acid gases from mixed gas streams is provided. Also provided is a process for removing acid gases from mixed gas streams using the disclosed solvent systems. The solvent systems may be utilized within a gas processing system.