TH4881B - A two-step process for removing lignin from lignocellulose fibers using first-stage peroxide-enriched oxygen. - Google Patents

Abstract

A two-step process for removing lignin from the pulp by chemical aerobic method was obtained. where 0.01% to 1% hydrogen peroxide is added to the first step. and choose to mix in the second step This invention is particularly suitable when further bleaching of this pulp with at least one chlorine dioxide step and at least one hydrogen peroxide step.

Claims (9)

1. a process that uses oxygen molecules to remove lignin from The lignocellulose fibers in the slurry from the digester without the power of the fibers are characterized by their step: a. Fade the unbleached slury from the concentrate by extracting the liquor fraction (liquor). ) First part from slory b. Mix sufficient thickening slory from step (a) into the first reagent mixture to achieve thickening. (consistency) containing fibers from 8% to 25% using oven drying basis. The reactive mixtures were alkaline enough equal to 1.5% to 4% sodium hydroxide and 0.01% to 1% hydrogen peroxide as compared to the weight of the fibers, which were dried in an oven. . Maintain the temperature of the first reaction mixture at 80 ° C to 110 ° C for 30 to 60 minutes with molecular oxygen. It is present at sub-pressures of 620 to 860 kPa (75-110 psi gauge) d. Thicken the first-stage mixture from the (c) stage by extraction with the liqueur fraction. E. Mix sufficient thickening slurry from step (d) into secondary reagent mixture to obtain fiber thickening from 8% to 25% wt. Using the drying basics in the oven, the mixture was alkaline enough equivalent to Sodium hydroxide from 1.5% to 4% and hydrogen peroxide 0% to 0.5% f. Maintain secondary reagent mixture at 70 ° C to 110 ° C for 30 to 60 minutes with oxygen. The molecules are present at sub-pressures of 170 to 860 kPa (20-110 psi gauge) and g. Separate lignin-removed fibers from the reactive mixture. Second stage and fibers Which has removed the lignin is solid The same or greater force as compared to the elixir. Nin is released using one step oxygen. 2. The process of claim No. 1, which is unique, is the substance The secondary reaction mixture also contains 0.01 to 1% hydrogen peroxide based on the fiber weight basis. To dry in the oven 3. The process of claim No. 1, which is unique, is the substance The first-stage mixture contains 0.1 to 0.5% hydrogen peroxide. 4. The process of claim No. 2, which is unique, is the substance The secondary reaction mixture contains 0.1 to 0.5% hydrogen peroxide. 5. The process of claim No. 2, which is unique, is the substance The first and second stage mixtures contain 0.1 to 0.5% hydrogen peroxide. 6. Fade process of lignocellulose fibers that remove lignin. Then in the slurry from the digester using the chlorine dioxide step and then the peroxide step Enhancement looks The only thing is to remove lignin from lignocellulose fibers in the form of The slurry obtained from the shredder using a procedure a. Fade the unbleached slory from the concentrator by Extract the first portion of liquor, slurry b. Mix sufficient thickening slurry from step (a) into the first reaction mixture to obtain thickening. (consistency) containing fibers from 8% to 25% using oven drying basis. The reactive mixtures described above have the same alkalinity as 1.5% to 4% sodium hydroxide and 0.1% to 1% hydrogen peroxide as compared to the weight of the fibers, which are dried in the oven.c. Maintain the temperature of the first reagent at about 80 ° C, 110 ° C, 30 to 60 minutes with oxygen. The molecules are present at sub-pressures of 620 to 860 kilPa (kPa) (75-110 psi gauge) d. Thicken the first-stage mixture from the (c) stage by extracting it from the liqueur. E. Mix sufficient thickening slory from step (d) into secondary reagent mixture to obtain fiber thickening from 8% to 25% by weight. Using an oven drying basis, the mixture was alkaline enough equivalent to Sodium hydroxide from 1.5 to 4% and hydrogen peroxide 0% to 1.0% f. Maintain secondary reagent mix at 70 ° C to 110 ° C for 30 to 60 minutes with oxygen. The molecules are present at sub-pressures of 170 to 860 kPa (20-110 psi gauge) and g. Separate lignin-removed fibers from the reactive mixture. Second stage and fibers Which has removed the lignin is solid Increased force compared to the fibers obtained from the slurry of the digester. 7. The process of claim No. 6, which is characterized by the substance The secondary reaction mixture also contains 0.1 to 1% hydrogen peroxide using an oven-dried fiber weight basis. 8. The process of claim No. 6, which is characterized by the substance The first-stage mixture contains 0.1 to 0.5% hydrogen peroxide. 9. The process of claim No. 7, which is characterized by the substance The second-stage mixture contains 0.1% to 0.5% hydrogen peroxide 1. 0. The process of claim Clause 7 has its unique characteristics as follows: Both first and second reagent mixtures contain 0.1 to 0.5% hydrogen peroxide.