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US 2004/0069427 A1Published application
Multi-stage AP mechanical pulping with refiner blow line treatment
OwnerEric Chao Xuinventor
Life of this patent
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Abstract
The invention combines the step of adding chemicals such as alkaline peroxide to an intermediate line after refining, with the step of applying chemicals such as alkaline peroxide as a pre-treatment before primary refining and/or applying chemicals such as alkaline peroxide at the primary refiner. This is implemented in the preferred embodiment, by pre-treating feed material, refining the materials into a pulp in a superatmospheric refiner, and adding chemicals in the post refining blow-line.
Claims43
An alkaline peroxide mechanical pulping process comprising the steps of:
- feeding a lignocellulosic material into a first press;
- pressing the lignocellulosic material;
- discharging the lignocellulosic material from the first press;
- impregnating the lignocellulosic material discharged from the first press with a first alkaline peroxide pretreatment solution and maintaining the impregnation for a first reaction time;
- feeding the impregnated lignocellulosic material to a refiner having an inlet and a rotating disc within a superatmospheric casing;
- refining the impregnated lignocellulosic material to form a primary pulp having a temperature of at least about 80 C;
- delivering a stream of primary pulp from the superatmospheric casing to an intermediate line while the primary pulp temperature is at least about 80 C;
- adding an alkaline peroxide intermediate line solution to the stream of primary pulp within the intermediate line while the primary pulp temperature is at least about 80 C;
- mixing the intermediate line solution and the stream of primary pulp to form a reaction mixture in the intermediate line;
- discharging the reaction mixture having a temperature of at least about 80 C into a retention vessel;
- retaining the reaction mixture in the retention vessel to produce a bleached material.
8 more elements
A chemimechanical pulping process comprising the steps of:
- feeding a lignocellulosic material into a first press;
- pressing the lignocellulosic material;
- discharging the lignocellulosic material from the first press;
- impregnating the lignocellulosic material discharged from the first press with a first chemical bleaching pretreatment solution and maintaining the impregnation for a first reaction time;
- feeding the lignocellulosic material impregnated with the first pretreatment solution to a refiner having an inlet and a rotating disc within a superatmospheric casing;
- refining the lignocellulosic material to form a primary pulp having a temperature of at least 80 C;
- while the primary pulp temperature is at least about 80 C, discharging the primary pulp from the casing to an intermediate line;
- while the primary pulp temperature is at least about 80 C, adding an alkaline peroxide intermediate line solution at the intermediate line which contains the primary pulp;
- mixing the intermediate line solution with the primary pulp;
- while the intermediate line solution and primary pulp mixture are at a temperature of at least about 80 C discharging the intermediate line solution and primary pulp mixture into a retention tower;
- retaining the mixture in the retention tower;
- and
- processing the primary pulp further to a secondary pulp.
10 more elements
An alkaline peroxide mechanical pulping process comprising the steps of:
- in a primary refiner having a superatmoshperic casing, refining a lignocellulosic material that has been pretreated and impregnated with at least a first alkaline peroxide pretreatment solution;
- discharging the lignocellulosic material at temperature of at least about 80 C into intermediate line having at least one solution inlet port;
- injecting an alkaline peroxide intermediate line solution through the at least one solution inlet port;
- mixing the intermediate line solution and the lignocellulosic material in the intermediate line;
- discharging the lignocellulosic material from the intermediate line at a temperature of at least about 80 C;
- and
- maintaining the discharged lignocellulosic material for a reaction period.
4 more elements
An alkaline peroxide mechanical pulping process comprising the steps of:
- feeding a lignocellulosic material into a first press;
- pressing the lignocellulosic material;
- discharging the lignocellulosic material from the first press;
- impregnating the lignocellulosic material discharged from the first press with a first alkaline peroxide pretreatment solution and maintaining the impregnation for a first reaction time;
- feeding the impregnated lignocellulosic material to a refiner having an inlet and a rotating disc within a superatmospheric casing;
- refining the impregnated lignocellulosic material to form a primary pulp;
- discharging the stream of primary pulp from the superatmospheric casing to an intermediate line;
- adding an alkaline peroxide intermediate line solution to the stream of primary pulp within the intermediate line;
- mixing the intermediate line solution and the stream of primary pulp to form a reaction mixture;
- discharging the reaction mixture into a retention vessel;
- retaining the reaction mixture in the retention vessel to produce a bleached material.
8 more elements
A chemimechanical pulping process comprising the steps of:
- feeding a lignocellulosic material into a press;
- pressing the lignocellulosic material;
- discharging the lignocellulosic material from the press;
- impregnating the lignocellulosic material discharged from the press with a chemical bleaching pretreatment solution;
- feeding the lignocellulosic material impregnated with the pretreatment solution to a refiner having an inlet and a rotating disc within a superatmospheric casing;
- refining the lignocellulosic material to form a primary pulp;
- discharging the primary pulp from the casing through an intermediate line;
- adding an alkaline peroxide solution at the intermediate line to the primary pulp;
- mixing the intermediate line solution with the primary pulp;
- delivering the intermediate line solution and primary pulp mixture to a retention tower;
- processing the primary pulp from the retention tower, into a secondary pulp.
8 more elements
An alkaline peroxide mechanical pulping process comprising the steps of:
- in a primary refiner having a superatmoshperic casing, refining a lignocellulosic material that has been pretreated and impregnated with at least a first alkaline peroxide pretreatment solution;
- discharging the lignocellulosic material into an intermediate line having at least one solution inlet port;
- injecting an alkaline peroxide intermediate line solution through the at least one solution inlet port;
- mixing the intermediate line solution and the lignocellulosic material;
- discharging the lignocellulosic material from the intermediate line;
- and
- retaining the discharged lignocellulosic material for a reaction period.
4 more elements
An alkaline peroxide mechanical pulping process comprises the steps of:
- in a refiner having a casing, additionally refining a lignocellulosic based material that has been previously pretreated and impregnated with at least a first alkaline peroxide pretreatment solution and which has been previously refined;
- discharging the lignocellulosic based material into an intermediate line having at least one solution inlet port;
- injecting an alkaline peroxide intermediate line solution through the at least one solution port;
- mixing the intermediate line solution and the lignocellulosic based material;
- discharging the lignocellulosic based material from the intermediate line;
- and
- retaining the discharged lignocellusic based material for a reaction period.
4 more elements
Dependencies are inferred from the claim text.