Abstract: A method to be used in conjunction with a single-stage or multi-stage process for leaching ash originating from the recovery boiler of a pulp mill, particularly when the ash contains a significant amount of carbonate, wherein calcium compounds, such as calcium oxide (CaO) or calcium hydroxide (Ca(OH)2), are employed as additives in one or more leaching stages, a liquid fraction formed in the leaching process is utilized outside the main chemical recovery cycle, such as a substitute for purchased sodium hydroxide in the bleaching line of the pulp mill, and a solids fraction may be mixed with a black-liquor stream of the mill or subjected to further processing to separate calcium compounds for recycle.

Abstract: A bottom grate for a crusher for chipping or comminuting material which includes: support ribs each substantially perpendicular to the rotational axis of the crusher; grate blades mounted to the support ribs and substantially parallel to the rotational axis, wherein the grate blades are releasably mounted to the support ribs and the grate blades each have a cutting edge proximate to a cutting or crushing rotor in the crusher; pulling members extending between two of the support members, wherein the pulling members are in tension and the tension in the pulling members binds the blades in the support members.

Abstract: A method and a liquor filter, in which liquor filter sealing medium is fed via a sealing medium channel (3) into an innermost sealing zone formed by an innermost sealing member (1), an outer seal (2) and the space between them at a causticizing plant of a chemical pulp mill. The sealing medium used is an alkaline sealing liquid and/or gas, which does not substantially dilute the liquor being filtered. Advantageously the sealing medium is filtrate from the liquor filter and/or gas taken from the interior of the liquor filter.

Abstract: The present invention relates to a method and an arrangement for burning lime mud into lime in a lime kiln. The lime mud flows counter-currently to flue gases from a feed end to a firing end and the fuel used is flue gas that is produced by gasifying a fuel in the presence of combustion air in a gasifier. The combustion air for gasification is preheated with heat generated in lime mud combustion. The arrangement is provided with a conduit between the lime kiln and the gasifier for leading air from the lime kiln into the gasifier as combustion air. At least a portion of the combustion air for gasification is preheated with heat generated in the lime mud combustion so that air is led into cooling of lime obtained in the combustion and further into the kiln, from or through the firing end of which air is taken into the gasification.

Abstract: A method associated for treating a precoat on a rotating filtering surface of lime sludge filter including: accumulating a precoat of lime sludge on the filtering surface by rotating the filtering surface in a first direction through a lime sludge slurry; after accumulating the precoat, rotating the filtering surface in an opposite direction to the first direction; while rotating the filtering surface in the opposite direction, spraying a liquid onto the precoat on the filtering surface wherein the spraying is applied to the precoat above a scraper adjacent the filtering surface and the spraying removes at least a portion of the precoat from the filtering surface, and flowing the removed precoat over the scraper and into a basin.

Abstract: A closing valve unit for a centrifugal cleaner arrangement including first and second connecting members configured to connect a cyclone to a centrifugal cleaner group, and a movable valve sandwiched between the first and second connecting members, the moveable valve including apertures commensurate with openings to feed and reject conduits of the cyclone and to openings to feed and reject conduits of the cyclone cleaner group, wherein the movable valve has a first position in which the apertures are aligned with the cyclone and cleaner group feed conduits and with the cyclone accept and cleaner group accept conduits, and a control element connected to the moveable valve and configured to move the moveable valve between the first position and the second positions.

Abstract: A recovery boiler plant of a chemical pulp mill including: a boiler including a lower region with an outlet to discharge smelt; a dissolving tank proximate to the outlet and configured to receive smelt; a smelt spout coupled to the outlet and including a chute extending from the outlet to a position at or over an inlet to the dissolving tank; and a shielding room including walls, a ceiling and a floor, wherein one of the walls includes a wall of the boiler, and the shielding room encloses a volume adjacent the boiler and above the dissolving tank, wherein the enclosed volume includes and the smelt spout and a working area in front of the smelt spout.

Abstract: The present invention relates to a method of producing steam at a digester plant of a chemical pulp mill. Black liquor is discharged from the digester at a first temperature and pressure. The black liquor is treated in a flash tank for generating flashed black liquor and flash steam at a second temperature and a second pressure, which are lower than the first temperature and pressure. The flashed black liquor is taken for further treatment to the evaporation plant. The flash steam is led to an indirect heat exchange contact with clean liquid in the reboiler for boiling the liquid and for generating steam. The steam is led from the reboiler into a fan or compressor for increasing the steam pressure to a third pressure, which is higher than the second pressure and for adjusting the pressure of the steam in the flash tank. Steam at a third pressure is used for pretreating comminuted cellulosic fiber material, such as chips, prior to cooking.

Abstract: In a boiler, a space is reserved to expand the boiler by increasing the front and rear walls. To expand the boiler, wall additions are added to increase the width of the front and rear walls. After the expansion, the distance between the front and rear walls is substantially the same distance between the front and rear walls before the expansion.

Abstract: A method for bleaching pulp is provided. In the method at least one tertiary amine compound is introduced into a process stage of bleaching. This process stage is a stage which comprises mixing pulp and a chlorine compound capable of bleaching.

Abstract: A rotary feeder for transferring loose material, said rotary feeder having a housing, where a rotor transfers material from the feed channel of the housing into the discharge channel of the housing, the rotor having blades for transferring the material, and a counter blade is fixed in the housing of the rotary feeder between the blades of the rotor for cutting oversized pieces of material. A filler is arranged in the feed channel of the rotary feeder, to prevent the formation of a protrusion in the feed channel that would disturb the flow of the material formed by the counter blade, the edge of the filler adjacent to the counter blade being arranged to yield, and the filler is arranged to return to its initial position after the cutting operation.

Abstract: The present invention relates to a method and a boiler for decreasing the amount of nitrogen oxides in flue gases of a boiler, which flue gases are generated in the combustion of fuels and air. The boiler has a water circulation system comprising superheaters (8) and a furnace (1) for combustion of fuel and for generating flue gases that contain nitrogen oxides, which flue gases mainly flow upwards in the furnace and further to the superheater zone and via other heat recovery surfaces of the boiler out of the boiler, and a nitrogen oxides reducing agent is introduced into the flue gases. It is essential that the nitrogen oxides reducing agent is introduced into the flue gases prior to the superheater zone, before which the temperature of the flue gases is decreased by means of at least one heat exchanger (15) that is located in the flue gas flow upstream of the introduction of the reducing agent, for obtaining a suitable temperature window in the flue gas flow in order to reduce nitrogen oxides.

Abstract: Method and apparatus for reducing the thickness of a precoat-layer accumulated on the filtering surface of a filter disc from a solids-containing suspension in a basin of a disc filter, said disc filter having two or more filter discs arranged on a shaft and between them at least one drop chute provided with a scraper on both sides, which scraper scrapes the cake filtered from the suspension on the filtering surfaces of the filter discs into the drop, the layer thickness of the precoat on the filtering surface is reduced by shortening the distance between the tips of the scrapers and the filtering surface, and the precoat thickness reduction is accomplished for the precoats on the filtering surface of the two filter discs on both sides of the drop chute non-simultaneously.

Abstract: A method for measuring and aligning a rotary cylindrical or other rotationally symmetrical apparatus, such as a kiln or a drum. The apparatus to be measured and aligned has a shell and at least one supporting ring. As the rotary apparatus is rotating under process conditions, measurement points are measured on the surface of the rotating object's shell in the axial direction on both sides of each supporting ring on the same circumferential line. Regression circles are calculated from the measured points, center points are determined for the calculated circles and a straight line and its center point are determined between the center points of the circles calculated on both sides of each supporting ring. A reference straight line is calculated for the center line of the shell and the object's shell is aligned to be straight by transferring the determined center points of the shell to the calculated reference line.

Abstract: The invention concerns an optical remote sensing system, comprising a reaction chamber adapted to host a chemical reaction in the shape of a scattering turbid atmosphere inside the reaction chamber. An optical active sensor is used to detect the three dimensional structure of an accumulation, such as a heap, inside the reaction chamber, suggesting various measurement methods.

Abstract: A method of and an apparatus for processing cellulose pulp of wood processing industry. The method and assembly may be used, on one hand, as a pressure diffuser for washing the pulp before an oxygen stage and, on the other hand, the separation of soap, gas and/or other light materials from filtrates and from black liquor of a cellulose mill in a pressurized device, as well as the new process connections enabled by the method. The method and apparatus may process filtrates from brown stock washing and bleaching as well as black liquors from a digesting department and an evaporation plant. By way of example, the filtrate of the washing department is pumped to the digesting department of a sulfate cellulose mill as well as the black liquor taken from the digesting department to an evaporation plant.

Abstract: A cover and frame assembly for a discharge end of a belt conveyor, the assembly including: a stationary frame supporting the discharge end and including sides extending beyond the discharge end; a cover having a top, opposite side walls extending down from the top and an end face extending between the side walls and down from the top; a rim along each of the side walls, wherein each the rim seats on an upper edge of one of the sides of the stationary frame, while the cover is closed over the discharge end, and a roller on each upper edge of the sides of the stationary frame, wherein each roller extends above the upper edge and seats in a hole or pit in the rim seated on the upper edge while the cover is closed, wherein the rim of each side wall slides over the corresponding roller as the cover is opened.

Abstract: A method for treating odorous gases of a chemical pulp mill, according to which method odorous gases are combusted in a separate combustion device and flue gas generated therein is scrubbed. The scrubbed flue gas is led into a recovery boiler. The flue gas is scrubbed in a series of scrubbers wherein scrubbing solution discharged from one scrubber may be fed to a preceding scrubber.

Abstract: A recovery boiler plant of a chemical pulp mill including: a boiler including a lower region with an outlet to discharge smelt; a dissolving tank proximate to the outlet and configured to receive smelt; a smelt spout coupled to the outlet and including a chute extending from the outlet to a position at or over an inlet to the dissolving tank; and a shielding room including walls, a ceiling and a floor, wherein one of the walls includes a wall of the boiler, and the shielding room encloses a volume adjacent the boiler and above the dissolving tank, wherein the enclosed volume includes and the smelt spout and a working area in front of the smelt spout.

Abstract: A method and assembly for separating contaminants from liquids, such as condensates, or vapors at an evaporation plant. The contaminants are separated from liquids by stripping when bringing a contaminant-enriched liquid into direct contact with a vapor by spraying or distributing the liquid into the vapor flowing in a vapor duct or onto wall surfaces in the vapor duct thus reducing the contaminant-content of the sprayed liquid and producing a cleaner liquid. The contaminants are enriched in the vapor. From vapors contaminants are separated by absorption when bringing a contaminant-enriched vapor into direct contact with a cleaner liquid by spraying or distributing the liquid into the vapor flowing in a vapor duct or onto wall surfaces in the vapor duct thus increasing the contaminant-content of the liquid, but producing a cleaned vapor.