Abstract: A method for removing hydrogen sulphide ions (HS?) from a liquor (300) of a pulp mill process, the method comprising pumping the liquor (300) to an injector arrangement (710) using a pump arrangement (720) such that the pumping of the liquor (300) through a jet nozzle (115) generates suction at a gas inlet (130), whereby reagent gas (310) is mixed with the liquor (300), and letting out the treated liquor (300) from the injector arrangement (710) to a vessel (200). In this way, the liquor (300) is treated to form at least partly treated liquor (300). A corresponding use of an injector arrangement. A system for performing the method.

Abstract: A method for removing hydrogen sulphide ions (HS?) from a liquor (300) of a pulp mill process, the method comprising pumping the liquor (300) to an injector arrangement (710) using a pump arrangement (720) such that the pumping of the liquor (300) through a jet nozzle (115) generates suction at a gas inlet (130), whereby reagent gas (310) is mixed with the liquor (300), and letting out the treated liquor (300) from the injector arrangement (710) to a vessel (200). In this way, the liquor (300) is treated to form at least partly treated liquor (300). A corresponding use of an injector arrangement. A system for performing the method.

Abstract: The invention relates to a method and apparatus for processing the black liquor of a pulp mill to recover the chemicals and energy therein. In the invention, the black liquor is pyrolyzed in a pyrolysis reactor (6), formed gaseous components are lead for utilization, sand is returned to a fluidized-bed boiler, and solid matter is mixed with water, whereby a soda-water solution is returned to the pulping process and solid carbon to the fluidized-bed boiler (1).

Abstract: The invention relates to a method and apparatus for processing the black liquor of a pulp mill to recover the chemicals and energy therein. In the invention, the black liquor is pyrolyzed in a pyrolysis reactor (4), formed gaseous components are lead for utilization, sand is returned to a fluidised-bed boiler, and solid matter is mixed with water, whereby a soda-water solution is returned to the pulping process and solid carbon to the fluidised-bed boiler (1).

Abstract: A method and an arrangement for reducing emissions of nitrogen oxides in a combustion apparatus provided with a tubular furnace. The method comprises burning odor gases at first sub-stoichiometrically, and subsequently supplying additional air to the furnace (3) in the transverse direction thereof in such a manner that the final air ratio is over 1. The arrangement comprises an additional air duct (7) which extends to the furnace of the boiler and from which additional air is supplied to the furnace (3) in the transverse direction of the furnace (3).