# US 5,701,829 A · Apparatus for recovering heat in a spent liquor recovery boiler > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,701,829 A - Document ID: US5701829A - Status: Granted - Kind: A - Application number: 08/416,753 - Filed: 1995-04-13 - Granted: 1997-12-30 - Earliest claimed: 1992-10-19 - Assignees: Ahlstrom Machinery Inc. - Inventors: Keijo Raak - Web page: https://patentgrep.com/patent/US5701829A ## CPC - F23G 7/04: of waste liquors, e.g. sulfite liquors - D21C 11/06: Treatment of pulp gases; Recovery of the heat content of the gases; {Treatment of gases arising from various sources in pulp and paper mills; Regeneration of gaseous SO2, e.g. arising from liquors containing sulfur compounds} - D21C 11/12: Combustion of pulp liquors - F22B 31/045: {Steam generators specially adapted for burning refuse} - F23G 5/46: Recuperation of heat - Y02E 20/12: Heat utilisation in combustion or incineration of waste - Y02P 70/10: Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working - F23G: CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION - D21C: PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR - F22B: METHODS OF STEAM GENERATION; STEAM BOILERS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract An apparatus for use in the pulp industry for recovering heat in the spent liquor recovery boiler, whereby the boiler walls are formed of water-cooled tubes connected to the water/steam circulation system of the boiler. Supply of air into the lower section of the furnace is effected symmetrically through air ports which are disposed at equal distances from the center of the furnace. The lower section of the furnace is preferably cylindrical and connected to a separate cooling medium circulation system. ## Claims ### Claim 1 Apparatus for use in the pulp industry for recovering heat in a spent liquor recovery boiler comprising: a recovery boiler having a furnace and a water steam circulation system, and having boiler walls that are formed of water-cooled tubes connected to said water/steam circulation system; a lower section of said boiler furnace in the shape of a vertical cylinder, which is a polygon in cross-section; and air ports disposed in said boiler walls of said polygon cross-section lower section, said air ports spaced substantially equal distances from a center point of said furnace lower section; and an upper section of said furnace which is a polygon in cross-section. ### Claim 2 (depends on 1) Apparatus as recited in claim 1 wherein both primary and secondary air ports are disposed in said lower section of said furnace. ### Claim 3 (depends on 1) Apparatus as recited in claim 1 wherein said lower section of said boiler comprises a bottom and walls that are farmed as a separate structure, and which is connected to a cooling medium circulation system distinct from said boiler steam circulation system. ### Claim 4 (depends on 3) Apparatus as recited in claim 3 wherein said lower section of said furnace is formed of water walls connected to a distinct forced circulation system of cooling medium distinct from said boiler steam/circulation system, and wherein said distinct system has a pressure that is lower than the pressure in said water/steam circulation system of said boiler. ### Claim 5 (depends on 3) Apparatus as recited in claim 3 wherein said lower section of said furnace is formed of water walls which are connected to a separate cooling medium circulation system distinct from said boiler system/circulation system and in which the cooling medium is air or inert gas. ### Claim 6 (depends on 3) Apparatus as recited in claim 3 wherein said lower section of said furnace is defined by water walls connected to a separate cooling medium circulation system distinct from said boiler steam/circulation system and in which the cooling medium is a liquid other than water. ### Claim 7 (depends on 3) Apparatus as recited in claim 3 wherein said lower section of said furnace, and an upper section of the furnace, are detachable from each other. ### Claim 8 (depends on 3) Apparatus as recited in claim 3 wherein said lower section of said furnace is an octagon or a decagon in cross-section. ### Claim 9 (depends on 1) Apparatus as recited in claim 1 wherein said lower section of said furnace is an octagon or a decagon in cross-section. ### Claim 10 (depends on 1) Apparatus as recited in claim 1 wherein said air ports of said lower section of said boiler are circular in cross-section. ### Claim 11 Apparatus for use in the pulp industry for recovering heat in a spent liquor recovery boiler comprising: a recovery boiler having a furnace, and a water steam/circulation system, and having boiler walls that are formed of water cooled tubes connected to said water/steam circulation system; a lower section of said boiler furnace in the shape of a vertical cylinder; air ports disposed in said boiler walls of said lower section spaced substantially equal distances from a center point of said furnace; and wherein said lower section of said boiler comprises bottom end walls that are formed as a separate structure, and which is connected to a cooling medium circulation system distinct from said boiler/steam circulation system. ### Claim 12 (depends on 11) Apparatus as recited in claim 11 wherein said lower section of said furnace is formed of water walls connected to a separate distinct forced circulation system of cooling medium distinct from said boiler steam/circulation system, and wherein said distinct system has a pressure that is lower than the pressure in said water/steam circulation system of said boiler. ### Claim 13 (depends on 11) Apparatus as recited in claim 11 wherein said lower section of said furnace is formed of water walls which are connected to a separate cooling medium circulation system distinct from said boiler system/circulation system and in which the cooling medium is air or inert gas. ### Claim 14 (depends on 11) Apparatus as recited in claim 11 wherein said lower section of said furnace is defined by water walls connected to a separate cooling medium circulation system distinct from said boiler steam/circulation system and in which the cooling medium is a liquid other than water. ### Claim 15 (depends on 11) Apparatus as recited in claim 11 wherein said lower section of said furnace, and an upper section of said furnace, are detachable from each other. ### Claim 16 (depends on 11) Apparatus as recited in claim 11 wherein both primary and secondary air ports are disposed in said lower section of said furnace. ### Claim 17 (depends on 11) Apparatus as recited in claim 11 wherein said lower section of said furnace is an octagon or a decagon in cross-section. ### Claim 18 (depends on 11) Apparatus as recited in claim 11 wherein an upper section of said furnace is a polygon in cross section and said air ports are spaced substantially equal distances from a center point of said furnace. ### Claim 19 (depends on 11) Apparatus as recited in claim 11 wherein said air ports of said lower section of said boiler are circular in cross-section.