公开(公告)号：EP0946408A1

公开(公告)日：1999-10-06

申请号：EP97943702.0

申请日：1997-10-09

申请人： Pulp and Paper Research Institute of Canada ,  ECO-TEC LIMITED

发明人： PALEOLOGOU, Michael ,  THOMPSON, Rokhsareh ,  BROWN, Craig, J. ,  SHEEDY, Michael

IPC分类号： B09B3 ,  B01J39 ,  C01B11 ,  C01B17 ,  C01D5 ,  C02F1 ,  D21C9

CPC分类号： C01B17/904 ,  C01B11/023 ,  C01D5/16 ,  Y10S423/14

摘要： A process employing a fixed-resin bed Acid Retardation Unit (ARU) to separate spent acid from chlorine dioxide generators into a de-acidified sodium sulfate component and a purified sulfuric acid component. The de-acidified sodium sulfate produced is returned to the chemical recovery cycle of the kraft mill in place of acidic chlorine dioxide generator effluent thereby avoiding the destruction of alkalinity in pulp mill liquors. In addition, sulfuric acid is purified providing an opportunity for reuse in various mill applications, and/or concentrated and recycled to the generator. Alternatively, to avoid high evaporation costs, the purified acid can be used to regenerate a cation-exchange unit (CEU) used in the conversion of sodium chlorate to a sodium chlorate/chloric acid mixture which is fed to the generator in place of sodium chlorate and sulfuric acid. Using this approach, the sulfuric acid requirement of chlorine dioxide generators and, in turn, the amount of acidic generator effluent can be reduced. The process is applicable to both atmospheric and subatmospheric chlorine dioxide generators. In the latter case, the concentration of the purified sulfuric acid from the ARU or any other acid separation system can be increased by using a portion of it to dissolve the sodium sesquisulfate by-product from such generators.

公开(公告)号：EP0954632B1

公开(公告)日：2002-09-25

申请号：EP98900833.9

申请日：1998-01-23

申请人： Pulp and Paper Research Institute of Canada ,  ECO-TEC LIMITED

发明人： PALEOLOGOU, Michael ,  THOMPSON, Rokhsareh ,  BERRY, Richard, McKinnon ,  BROWN, Craig, J. ,  SHEEDY, Michael

IPC分类号： D21C11/00

CPC分类号： D21C11/005 ,  B01J43/00 ,  D21C11/04 ,  Y10S210/928

摘要： A process using an amphoteric ion-exchange resin, also known as a "snake-cage polyelectrolyte" resin, contained in an ion retardation unit (9) separates kraft white liquor (8) into sulphide-rich (12) and caustic-rich (10) components. The sulphide-rich component (12) can be used in the initial stage of pulping (1), pretreatment of wood chips prior to pulping, or it can be used to make polysulphide-rich liquor. The caustic-rich component (10) can be used in the final delignification phase, in place of sodium hydroxide or white liquor in oxygen delignification, pH adjustment and flue gas scrubbing. The same system can be used to separate green (6) and polysulphide liquors (8a) into sulphide-rich and sulphide-poor components, and to remove sulphide from other mill caustic streams contaminated with sulphide.

公开(公告)号：EP0954632A1

公开(公告)日：1999-11-10

申请号：EP98900833.0

申请日：1998-01-23

申请人： Pulp and Paper Research Institute of Canada ,  ECO-TEC LIMITED

发明人： PALEOLOGOU, Michael ,  THOMPSON, Rokhsareh ,  BERRY, Richard, McKinnon ,  BROWN, Craig, J. ,  SHEEDY, Michael

IPC分类号： B01J43 ,  D21C11

CPC分类号： D21C11/005 ,  B01J43/00 ,  D21C11/04 ,  Y10S210/928

摘要： A process using an amphoteric ion-exchange resin, also known as a 'snake-cage polyelectrolyte' resin, contained in an ion retardation unit (9) separates kraft white liquor (8) into sulphide-rich (12) and caustic-rich (10) components. The sulphide-rich component (12) can be used in the initial stage of pulping (1), pretreatment of wood chips prior to pulping, or it can be used to make polysulphide-rich liquor. The caustic-rich component (10) can be used in the final delignification phase, in place of sodium hydroxide or white liquor in oxygen delignification, pH adjustment and flue gas scrubbing. The same system can be used to separate green (6) and polysulphide liquors (8a) into sulphide-rich and sulphide-poor components, and to remove sulphide from other mill caustic streams contaminated with sulphide.

公开(公告)号：EP0946408B1

公开(公告)日：2001-02-21

申请号：EP97943702.7

申请日：1997-10-09

申请人： Pulp and Paper Research Institute of Canada ,  ECO-TEC LIMITED

发明人： PALEOLOGOU, Michael ,  THOMPSON, Rokhsareh ,  BROWN, Craig, J. ,  SHEEDY, Michael

IPC分类号： C01B11/02 ,  C01D5/16 ,  C01B17/90

CPC分类号： C01B17/904 ,  C01B11/023 ,  C01D5/16 ,  Y10S423/14

公开(公告)号：EP0799086A1

公开(公告)日：1997-10-08

申请号：EP95940924.0

申请日：1995-12-20

申请人： Pulp and Paper Research Institute of Canada

发明人： PALEOLOGOU, Michael ,  BERRY, Richard, McKinnon ,  THOMPSON, Rokhsareh ,  WEARING, James, Theodore

IPC分类号： B01D61 ,  D21C11

CPC分类号： B01D61/44 ,  B01D61/445 ,  D21C11/066

摘要： Alkali metal hydroxide and acid are recovered from alkali metal salts by water-splitting. A two-compartment cell employs monovalent anion-selective membranes and bipolar membranes; a three-compartment cell (1) employs monovalent anion-selective membranes (3), cation-selective membranes (4) and bipolar membranes (2a, 2b). A particular application is the conversion of the Electrostatic Precipitator Catch of the recovery boiler of coastal and/or closed-cycle kraft pulp mill with reuse of the sodium/potassium hydroxide and sulfate, depleted in chloride.

公开(公告)号：EP0799086B1

公开(公告)日：1999-03-03

申请号：EP95940924.4

申请日：1995-12-20

申请人： Pulp and Paper Research Institute of Canada

发明人： PALEOLOGOU, Michael ,  BERRY, Richard, McKinnon ,  THOMPSON, Rokhsareh ,  WEARING, James, Theodore

IPC分类号： B01D61/44 ,  D21C11/00

CPC分类号： B01D61/44 ,  B01D61/445 ,  D21C11/066

摘要： Alkali metal hydroxide and acid are recovered from alkali metal salts by water-splitting. A two-compartment cell employs monovalent anion-selective membranes and bipolar membranes; a three-compartment cell (1) employs monovalent anion-selective membranes (3), cation-selective membranes (4) and bipolar membranes (2a, 2b). A particular application is the conversion of the Electrostatic Precipitator Catch of the recovery boiler of coastal and/or closed-cycle kraft pulp mill with reuse of the sodium/potassium hydroxide and sulfate, depleted in chloride.