Abstract: The invention relates to a method and a system for adjusting S/Na-balance of a sulphate pulp mill, wherein a pulp mill CNCG stream containing sulphur compounds is first scrubbed with an aqueous scrubbing solution containing an alkaline agent, thereby producing an aqueous spent scrubbing solution containing sulphides, which is then oxidized in a bioreactor by means of sulphur-oxidizing microbes, thereby obtaining an aqueous suspension containing elemental sulphur from which the elemental sulphur can be separated as a precipitate and the residual solution may be used for replenishing the aqueous scrubbing solution.

Abstract: The invention relates to a method and a system for adjusting S/Na-balance of a pulp mill, wherein an aqueous pulp mill liquor containing sulphides is diverted into a bioreactor and oxidized by means of sulphur-oxidizing microbes, thereby producing an aqueous suspension from which elemental sulphur can be separated as a precipitate and the residual solution may be directed to causticizing. Optionally, prior to oxidation in the bioreactor, the aqueous pulp mill liquor may be first stripped to obtain a gas stream containing H2S which is then scrubbed with a scrubbing solution to obtain an aqueous spent scrubbing solution containing sulphides, in which case the residual solution can be used to replenish the scrubbing solution.

Abstract: The invention relates to a method and a system for adjusting S/Na-balance of a pulp mill, wherein an aqueous pulp mill liquor containing sulphides is diverted into a bioreactor and oxidized by means of sulphur-oxidizing microbes, thereby producing an aqueous suspension from which elemental sulphur can be separated as a precipitate and the residual solution may be directed to causticizing. Optionally, prior to oxidation in the bioreactor, the aqueous pulp mill liquor may be first stripped to obtain a gas stream containing H2S which is then scrubbed with a scrubbing solution to obtain an aqueous spent scrubbing solution containing sulphides, in which case the residual solution can be used to replenish the scrubbing solution.

Abstract: The invention relates to a method and a system for adjusting S/Na-balance of a sulphate pulp mill, wherein a pulp mill CNCG stream containing sulphur compounds is first scrubbed with an aqueous scrubbing solution containing an alkaline agent, thereby producing an aqueous spent scrubbing solution containing sulphides, which is then oxidized in a bioreactor by means of sulphur-oxidizing microbes, thereby obtaining an aqueous suspension containing elemental sulphur from which the elemental sulphur can be separated as a precipitate and the residual solution may be used for replenishing the aqueous scrubbing solution.

Abstract: A system for producing aqueous sulphuric acid is provided, the system including a first heat exchanger configured to cool aqueous sulphuric for producing cooled aqueous sulphuric acid; a pre-cooling unit comprising an inlet or inlets for receiving the gas containing sulphur trioxide and the cooled aqueous sulphuric acid, an outlet for letting out aqueous sulphuric acid and the gas containing sulphur trioxide, and a first nozzle for spraying the cooled aqueous sulphuric acid onto the gas containing sulphur trioxide. The system further includes a condensation tower comprising a first inlet for receiving the cooled gas containing sulphur trioxide and aqueous sulphuric acid from the pre-cooling unit and means for circulating the aqueous sulphuric acid within the condensation tower by spraying. An associated method and pre-cooling unit suitable for cooling gas comprising sulphur trioxide from at least 400° C. to at most 150° C. are also provided.

Abstract: A system (100) for producing aqueous sulphuric acid. The system (100) comprises a first heat exchanger (410) configured to cool water and/or aqueous sulphuric for producing cooled water and/or cooled aqueous sulphuric acid; a pre-cooling unit (200) configured to pre-cool some gas containing sulphur trioxide, the pre-cooling unit (200) comprising an inlet or inlets (212, 214) for receiving [i] the gas containing sulphur trioxide and [ii] the cooled water and/or the cooled aqueous sulphuric acid, an outlet (216) for letting out aqueous sulphuric acid and the gas containing sulphur trioxide, and a first nozzle (220) for spraying the cooled water and/or the cooled aqueous sulphuric acid onto the gas containing sulphur trioxide to cool the gas containing sulphur trioxide.

Abstract: A method of scrubbing flue gases of two or more diesel engines and a scrubber for scrubbing flue gases of two or more diesel engines. The scrubber (1) comprises scrubbing means (3) for scrubbing the flue gases, and conduits (4) for conveying the flue gases to said scrubbing means (3) to be scrubbed in the same scrubbing process. The different flue gas flows are arranged to be conveyed in separate conduits (4) all the way to the scrubbing means (3).

Abstract: A method and an equipment for reducing sulphur dioxide emissions of a marine engine, wherein flue gases are scrubbed with a scrubbing solution in a scrubber. Fresh water with added sulphur removal reagent is used as the scrubbing solution.

Abstract: A method and an apparatus for removing carbon dioxide (CO2) from sulphur dioxide containing (SO2) flue gases, wherein the flue gases are washed with washing solution in a scrubber, which comprises at least two washing stages. In the first washing stage the flue gases are washed for removing the sulphur dioxide in the flue gases and after that in the second washing stage for removing carbon dioxide (CO2). Sodium carbonate solution (Na2CO3) is used as washing solution in both the first and the second washing stages.

Abstract: A method of scrubbing flue gases of two or more diesel engines and a scrubber for scrubbing flue gases of two or more diesel engines. The scrubber (1) comprises scrubbing means (3) for scrubbing the flue gases, and conduits (4) for conveying the flue gases to said scrubbing means (3) to be scrubbed in the same scrubbing process. The different flue gas flows are arranged to be conveyed in separate conduits (4) all the way to the scrubbing means (3).

Abstract: A method and an equipment for reducing sulphur dioxide emissions of a marine engine, wherein flue gases are scrubbed with a scrubbing solution in a scrubber. Fresh water with added sulphur removal reagent is used as the scrubbing solution.

Abstract: A method and an apparatus for removing carbon dioxide (CO2) from sulphur dioxide containing (SO2) flue gases, wherein the flue gases are washed with washing solution in a scrubber, which comprises at least two washing stages. In the first washing stage the flue gases are washed for removing the sulphur dioxide in the flue gases and after that in the second washing stage for removing carbon dioxide (CO2). Sodium carbonate solution (Na2CO3) is used as washing solution in both the first and the second washing stages.

Abstract: A method of reducing NOX compounds in the odor gases of a recovery boiler. In the method, ammonia in the odor gases is separated before the odor gases are combusted, the ammonia being then introduced into a recovery boiler at the pulp mill or in a separate catalyzer, where the ammonia reacts with nitrogen oxide forming water and molecular nitrogen.

Abstract: Process for removing nitrogen oxides from the flue gases of a soda recovery boiler of a pulp mill. In the method, to the flue gases of the soda recovery boiler is at first fed an oxidizing agent, such as chlorine dioxide or ozone, which oxidizes nitrogen oxide to nitrogen dioxide. Subsequently, the flue gases are led into a flue gas scrubber, in which a reagent coming from the circulation of chemicals of the pulp mill is injected into the flue gases, which reagent brought into contact with the nitrogen dioxide reduces the nitrogen dioxide to nitrogen. The flue gas containing nitrogen is led out of the scrubber and the oxidized reagent is led back to the circulation of chemicals of the pulp mill.

Abstract: A method for adjusting the sulphur/sodium ratio in a soda recovery boiler when strong sulphurous odour gases are burned therein. According to the method, sodium is introduced into the soda recovery boiler in an amount proportional to the amount of sulphur either as sodium hydroxide, sodium carbonate compounds or soap, whereby the sodium and sulphur react, forming sodium sulphate, which can be removed from the flue gases together with fly ash.

Abstract: The invention relates to a process for the removal of sulfur dioxide from hot flue gases (8) which have been obtained by burning a sulfur-containing substance (4) in a boiler (1). In the process, a substance (6), such as lime or limestone, which reacts with sulfur dioxide to form a solid product is fed into the boiler or into the reaction zone (2) subsequent to the boiler, the hot flue gases (8) are cooled in the reaction zone (2) by feeding into it at maximum such an amount of water as the hot flue gases are capable of evaporating, and the substantially dry solid products are separated (3) in the form of dust (10) from the cooled flue gases. According to the invention, the flue gases (11) thus obtained are scrubbed (13) with an alkaline aqueous solution (15) in order to remove the remaining sulfor dioxide and dust from the flue gases, and part (9') of the cycled scrubbing solution (9) is fed into the boiler (1) or the reaction zone (2) in order to evaporate the water from this solution.

Abstract: A nozzle assembly includes at least one nozzle (1) for the injection of liquid moistening medium into a flow of flue gas, especially in view of cooling the flue gas, and a body (2) for directing the moistening medium to the nozzle. Nozzle (1) and body (2) are essentially disposed in a flue-gas flow duct or the like. In the flue-gas flow duct is fitted a housing (3) which essentially surrounds nozzle (1) and body (2). Housing (3) ia provided with an an aperture (10), which can be closed by a closing means (9) and through which a jet of moistening medium passes into a flow of flue gas.