Abstract: A method of drying black liquor to a dry solids content of about 100% in which water is evaporated from the black liquor by direct heat exchange contact with hot smelt from a recovery furnace in which the dried black liquor is burned.
Abstract: A method of dehumidifying gas in which gas is brought into direct contact with an absorption liquid in one or more stages, and in which the absorption liquid in at least one stage comprises a salt solution which includes an amount of salt crystals so that the concentration of the salt solution will not be substantially reduced in the absorption stage.
Abstract: A method and system for cooling pulp discharged from a batch type digester and recovering heat from it. A stream of pulp together with spent cooking liquor is discharged from a batch digester to a diffuser and passed through the diffuser at substantially the same pressure as that of the digester. The pulp stream is caused to flow between screens and hot spent cooking liquor is displaced with cooler liquor flowing across the pulp stream thereby lowering the temperature of the pulp stream. The displayed cooking liquor and the pulp is withdrawn from the diffuser.
Abstract: Process for the evaporative concentration of liquids. Vaporization is carried out by indirect heat exchange with a heating fluid in an evaporator. The vapor produced in the evaporator is thereafter condensed in a condenser by indirect heat exchange with a cooling liquid which is mainly composed of the liquid to be concentrated or the liquid which has already been concentrated in the evaporator. The vapor pressure over the cooling liquid in the condenser may be lowered by causing gas to flow in contact with the cooling liquid.
Abstract: The present invention relates to a method and apparatus for evaporating waste liquor produced when cooking fibrous material containing cellulose in a continuous pulp digester. In the continuous cooking process, fibrous material is heated to the process temperature by direct or indirect vapor heating in the digester at an increased pressure. The invention especially relates to digesters, in which fibrous material is heated directly with vapor.
January 11, 1989
Date of Patent:
July 31, 1990
Ahlstromforetagen Svenska AB
Kaj Henricson, Ryham, Rolf, Sannholm, Krister
Abstract: A process and apparatus for the gasification of partially dried fuel with hot gas which has been heated by bringing it into contact with an inert hot heat carrier. The fuel gases generated during the gasification process are further combusted and utilized for heating the inert heat carrier. The process and apparatus can be combined with a process and apparatus for generating steam from wet fuel wherein water is evaporated from the wet fuel by bringing the fuel into direct contact with superheated steam. The steam is superheated by bringing it into contact with a second hot heat carrier. The second heat carrier is heated by bringing it into direct contact with the fuel gas produced by combusting the fuel gas from the gasification process.
Abstract: A method for recovering turpentine and heat in a TMP process in which woodchips are heated in a preheater and the vent vapors from the preheater are passed to the condensing vapor zone of an evaporator condenser-reboiler having a condensing vapor zone and a boiling liquid zone. A major portion of the vent vapors are condensed so as to produce a turpentine-lean condensate and turpentine-rich vapor phase. The turpentine-rich vapor phase is withdrawn from the evaporator and passed to a turpentine condenser where it is cooled by indirect heat exchange contact with a cooling liquid to produce a condensate containing immiscible turpentine and aqueous phases. The turpentine and the aqueous phases are separated.
Abstract: A process and apparatus for generating steam from wet fuel, wherein water is evaporated from the wet fuel by bringing the fuel into direct contact with superheated steam. The steam is superheated by bringing it into contact with a hot heat carrier. The heat carrier is heated by bringing it into direct contact with flue gas produced by burning the dried fuel and the heat carrier is used to superheat the steam.
Abstract: A cooling process and apparatus which utilizes the lower water vapor pressure above a fluid such as water-salt solutions of, for example, calcium chloride, lithium chloride, lithium bromide or mixtures thereof. Heat is then removed from the fluid by indirect contact with a circulating water stream in a heat exchanger. Water which has taken up heat from the fluid is expanded at reduced pressure to release water vapor and lower the temperature of the water. The water vapor is then absorbed in a salt solution having a higher temperature but a lower water vapor pressure than that of the released water vapor. The remaining water is recirculated to the heat exchanger.
Abstract: An air conditioning process and apparatus with absorption of water vapor in a circulating absorption liquid containing an aqueous salt solution. The absorption liquid to be supplied to the absorber is cooled by indirect contact with a circulating water stream in a heat exchanger. The circulating water is expanded at reduced pressure to release water vapor and lower the temperature of the water. The water vapor is thereafter absorbed in absorption liquid from the absorber.
Abstract: An air conditioning process and apparatus includes absorption of water vapor in a circulating absorption liquid composed of an aqueous salt solution. The absorption liquid is regenerated by evaporative concentration by indirect heat exchange with a heating fluid in an evaporator. The water vapor produced in the evaporator is condensed in a condenser by indirect heat exchange with a cooling liquid which is mainly composed of the absorption liquid to be concentrated or which has already been concentrated in the evaporator. The water vapor pressure over the cooling liquid in the condenser is lowered by causing gas to flow in contact with the cooling liquid.
Abstract: In a falling film evaporator of the vertical-tube type in which liquid to be evaporated is supplied at the top on the outer surface of vertical heat exchanger tubes and the heat medium is supplied to the heat exchanger tubes at the bottom for flow inside the same, at least one larger tube element than the heat exchanger tubes is disposed between and fixed to tube plates at the both ends of the group of tubes to stabilize the group of tubes against tension and especially compression stresses.
Abstract: The invention relates to a method for evaporation of spent liquor by heat from a blow condenser where blow steam from a pulp cooker is condensed in a direct condenser connected with a hot water accumulator. Spent liquor heated indirectly by hot water from the accumulator is brought to expand and released expansion vapor is used as a heat medium in a following evaporation stage. The apparatus comprises a heat exchanger, at least one flash tank and at least one evaporation unit, the heat exchanger being disposed to receive hot water from the upper part of the accumulator and to return it to its lower part and thus heat the spent liquor, and the flash tank being disposed to receive spent liquor heated in the heat exchanger and to release liquor vapor and spent liquor to the evaporation unit.
Abstract: Calcium containing sulphate spent liquor is deactivated by means of heating. Spent liquor is heated by means of direct condensing in a flash-steam-system. Liquor vapors generated during expansion of the already deactivated spent liquor are used for heating the spent liquor. Spent liquor is led to a retention tank through n+1 in series connected direct condensers (DK I-DK V) and from the retention tank through n in series connected flash tanks (FT I-FT IV) disposed counter-currently to the direct condensers. In the last one of the direct condensers (DK V) the liquor is heated by means of externally supplied steam; in all others (DK I-DK IV) by means of expansion vapor.