Pulping process

Claim 2

A pollution-free process for producing wood pulp in any desired grade from any desired wood specie without the use of cooking liquors comprising the steps of: providing a steam-jacketed digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g., under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin containing solution from said pulp.

Claim 3

The process of claim 1 further comprising: recovering the lignin solvent from said lignin-containing solution for reuse in said process.

Claim 4

The process of claim 2 wherein said solvent is recovered by distillation.

Claim 5

The process of claim 2 comprising removing a major portion of the water in said lignin-containing solution by evaporation to form a lignin concentrate; and collecting said water.

Claim 6

The process of claim 4 further comprising washing said pulp a first time by slurrying said pulp in water and subsequently separating said wash water from said pulp; purifying said water by evaporation; and condensing the purified water, collecting said condensate for reuse.

Claim 7

The process of claim 5 further comprising washing said pulp a second time by slurrying said pulp in water and subsequently separating said wash water from said pulp; collecting said wash water for reuse.

Claim 8

The process of claim 5 wherein said wash water is admixed with the lignin containing solution from the defibrator for purification.

Claim 9

The process of claim 1 wherein said chips are impregnated from 10 to about 60 minutes in said vessel.

Claim 10

The process of claim 8 wherein said impregnated chips are digested from 10 to about 60 minutes in said vessel.

Claim 11

The process of claim 1 wherein said solvent is monoethanolamine.

Claim 12

The process of claim 1 wherein said chips are impregnated in a first digester vessel, and after separating the liquid and gaseous reactant by-products therefrom said process further comprises: providing a second digester vessel; conveying said chips to said second digester vessel for digesting said impregnated chips in sulfur dioxide gas.

Claim 13

A process for producing a lignin hardboard from wood chips comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, an on all sides of said chips at a temperature of at least about 250° F., for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g., under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; grinding said digested chips; and heating said ground chips under pressure to form said board.

Claim 14

A process for producing a lignin hardboard from wood chips comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, an on all sides of said chips at a temperature of at least about 250° F., for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g., under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; grinding said digested chips; and heating said ground chips under pressure to form said board.

Claim 15

The process of claim 12 wherein said board is formed in a steam press.

Claim 16

The process of claim 13 further comprising applying about 900 pounds pressure to said ground chips in said press with about 30 pounds of steam pressure.

Claim 17

The process of claim 12 wherein said chips are impregnated in a first digester vessel, and after separating the liquid and gaseous reactant by-products therefrom said process further comprises: providing a second digester vessel; conveying said chips to said second digester vessel for digesting said impregnated chips in sulfur dioxide gas.

Claim 18

A process for producing a lignin resin comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin containing solution from said pulp.

Claim 19

A process for producing a lignin resin comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin containing solution from said pulp.

Claim 20

The process of claim 16 further comprising: recovering the lignin solvent from said lignin containing solution for reuse in said process; removing a major portion of the water in said lignin containing solution by evaporation to form a lignin concentrate; admixing formaldehyde with said lignin concentrate to form a lignin-formaldehyde resin.

Claim 21

The process of claim 17 wherein said concentrate is admixed in about equal parts with a 30 percent aqueous formaldehyde solution.

Claim 22

A process for producing a lignin-resin glue comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin containing solution from said pulp; recovering the lignin solvent from said lignin containing solution for reuse in said process; removing a major portion of the water in said lignin containing solution by evaporation to form a lignin concentrate; admixing formaldehyde and phenol with said lignin-resin concentrate to form a lignin-resin glue.

Claim 23

A process for producing a lignin-resin glue comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin containing solution from said pulp; recovering the lignin solvent from said lignin containing solution for reuse in said process; removing a major portion of the water in said lignin containing solution by evaporation to form a lignin concentrate; admixing formaldehyde and phenol with said lignin-resin concentrate to form a lignin-resin glue.

Claim 24

The process of claim 19 wherein said glue comprises about 10 parts lignin concentrate, about 10 parts of a 30 percent aqueous formaldehyde solution, and about 1 part phenol.

Claim 25

A process for preparing a lignin-resin board comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F., for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin containing solution from said pulp; recovering the lignin solvent from said lignin containing solution for reuse in said process; removing a major portion of the water in said lignin containing solution by evaporation to form a lignin concentrate; admixing formaldehyde with said lignin concentrate to form a lignin-formaldehyde resin; admixing said resin and said pulp; heating said mixture under pressure to form a lignin-resin board.

Claim 26

A process for preparing a lignin-resin board comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F., for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin containing solution from said pulp; recovering the lignin solvent from said lignin containing solution for reuse in said process; removing a major portion of the water in said lignin containing solution by evaporation to form a lignin concentrate; admixing formaldehyde with said lignin concentrate to form a lignin-formaldehyde resin; admixing said resin and said pulp; heating said mixture under pressure to form a lignin-resin board.

Claim 27

The process of claim 21 wherein said board is formed in a steam press.

Claim 28

The process of claim 22 further comprising applying about 900 pounds pressure to said pulp mixture in said press with about 30 pounds of steam pressure.

Claim 29

The process of claim 21 wherein said chips are impregnated for from 10 to 30 minutes and digested for from 10 to 30 minutes in said vessel.

Claim 30

A process for producing container grade pulp comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below and on all sides of said chips at a temperature of at least 250° F. for from 10 to 30 minutes; separating said liquid and gaseous contents of said vessel from said chips; digesting said impregnated chips in sulfur dioxide gas initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least 230° F. for from 10 to 30 minutes; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with monoethanolamine; and extracting lignin from said digested chips by agitating said chips and monoethanolamine in a defibrator to form a pulp slurry; separating the lignin containing liquid from said pulp.

Claim 31

A process for producing container grade pulp comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below and on all sides of said chips at a temperature of at least 250° F. for from 10 to 30 minutes; separating said liquid and gaseous contents of said vessel from said chips; digesting said impregnated chips in sulfur dioxide gas initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least 230° F. for from 10 to 30 minutes; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with monoethanolamine; and extracting lignin from said digested chips by agitating said chips and monoethanolamine in a defibrator to form a pulp slurry; separating the lignin containing liquid from said pulp.

Claim 32

The process of claim 25 wherein said chips are impregnated in a first digester vessel, and after separating the liquid and gaseous reactant by-products therefrom said process further comprises: providing a second digester vessel; conveying said chips to said second digester vessel for digesting said impregnated chips in sulfur dioxide gas.

Claim 33

A process for producing dissolving grade or high grade paper pulp comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous solution and sulfur dioxide gas under a pressure of at least about 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F. for at least about 60 minutes; separating said liquid and gaseous contents of said vessel from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for from about 30 to about 60 minutes; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with monoethanolamine; and extracting lignin from said digested chips by agitating said chips and monoethanolamine in a defibrator to form a pulp slurry; separating the lignin containing liquid from said pulp; washing said pulp a first time by slurrying said pulp in water and subsequently separating said wash water from said pulp; washing said pulp a second time by slurrying said pulp in water and subsequently separating said wash water from said pulp.

Claim 34

A process for producing dissolving grade or high grade paper pulp comprising the steps of: providing a digester vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous solution and sulfur dioxide gas under a pressure of at least about 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F. for at least about 60 minutes; separating said liquid and gaseous contents of said vessel from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for from about 30 to about 60 minutes; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with monoethanolamine; and extracting lignin from said digested chips by agitating said chips and monoethanolamine in a defibrator to form a pulp slurry; separating the lignin containing liquid from said pulp; washing said pulp a first time by slurrying said pulp in water and subsequently separating said wash water from said pulp; washing said pulp a second time by slurrying said pulp in water and subsequently separating said wash water from said pulp.

Claim 35

The process of claim 27 wherein said chips are impregnated in a first digester vessel, and after separating the liquid and gaseous reactant by-products therefrom said process further comprises; providing a second digester vessel; conveying said chips to said second digester vessel for digesting said impregnated chips in sulfur dioxide gas.

Claim 36

A process for producing a liquid fertilizer comprising the steps of: providing a digester vessel; admixing chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips and form gaseous by-products; separating the gaseous reactant by-products from said digester chips; combining the liquid and gaseous reactant by-products of impregnation and digestion; reacting said by-products with a sulfite oxidizing agent to form sulfate compounds; neutralizing said reactants; recovering at least a major portion of the water from said reactants to form a liquid fertilizer concentrate.

Claim 37

A process for producing a liquid fertilizer comprising the steps of: providing a digester vessel; admixing chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least about 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in sulfur dioxide gas, initially under a pressure of at least about 50 p.s.i.g. under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips and form gaseous by-products; separating the gaseous reactant by-products from said digester chips; combining the liquid and gaseous reactant by-products of impregnation and digestion; reacting said by-products with a sulfite oxidizing agent to form sulfate compounds; neutralizing said reactants; recovering at least a major portion of the water from said reactants to form a liquid fertilizer concentrate.

Claim 38

The process of claim 29 wherein said oxidizing agent is nitric acid.

Claim 39

The process of claim 29 wherein said oxidizing agent is ferric ion.

Claim 40

The process of claim 29 further comprising: reacting said by-products with a metallic chelating agent to form chelates with the organic constituents thereof.

Claim 41

The process of claim 32 further comprising reacting said by-products with said metallic chelating agent in an electrolytic cell wherein said agent enters solution for reaction with said by-products at the anode of said cell by ionization of said anode.

Claim 42

A pollution-free process for producing wood pulp in any desired grade from any desired wood specie without the use of cooking liquors comprising the steps of: providing a vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in said vessel by admitting sulfur dioxide gas thereinto until the internal pressure is at least about 50 p.s.i.g., said chips being under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips and cause the pressure within said vessel to substantially decrease; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin-containing solution from said pulp.

Claim 43

A pollution-free process for producing wood pulp in any desired grade from any desired wood specie without the use of cooking liquors comprising the steps of: providing a vessel; admitting chips of wood to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; digesting said impregnated chips in said vessel by admitting sulfur dioxide gas thereinto until the internal pressure is at least about 50 p.s.i.g., said chips being under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips and maintaining said chips at a temperature of at least about 230° F. for an amount of time of up to about one hour effective to destroy at least a major portion of the lignin-cellulose bonds in said chips and cause the pressure within said vessel to substantially decrease; separating the gaseous contents of said vessel from said digested chips; admixing said digested chips with a lignin solvent; and extracting lignin from said digested chips by agitating said chips and solvent in a defibrator to form a pulp slurry; separating the lignin-containing solution from said pulp.

Claim 44

The process of claim 34 further comprising: recovering the lignin solvent from said lignin containing solution for reuse in said process.

Claim 45

The process of claim 35 wherein said solvent is recovered by distillation.

Claim 46

The process of claim 35 comprising removing a major portion of the water in said lignin containing solution by evaporation to form a lignin concentrate; and collecting said water.

Claim 47

The process of claim 34 further comprising washing said pulp a first time by slurrying said pulp in water and subsequently separating said wash water from said pulp; purifying said water by evaporation; and condensing the purified water, collecting said condensate for reuse;

Claim 48

The process of claim 38 further comprising washing said pulp a second time by slurrying said pulp in water and subsequently separating said wash water from said pulp collecting said wash water for reuse.

Claim 49

The process of claim 38 wherein said wash water is admixed with the lignin containing solution from the defibrator for purification.

Claim 50

The process of claim 34 wherein said chips are impregnated from 10 to 90 minutes in said vessel.

Claim 51

The process of claim 34 wherein said impregnated chips are digested from 10 to about 60 minutes in said vessel.

Claim 52

The process of claim 34 wherein said solvent is monoethanolamine.

Claim 53

The process of claim 34 wherein said chips are impregnated in a first vessel, and after separating the liquid and gaseous reactant by-products therefrom said process further comprises: providing a second digester vessel; conveying said chips to said second vessel for digesting said impregnated chips in sulfur dioxide gas.

Claim 54

The process of claim 34 wherein the step of separating the gaseous contents of the vessel from said chips comprises: providing first and second storage vessels; venting the gaseous contents of said vessel incrementally into said first vessel; conveying each increment of said gaseous contents from said first to said second vessel for storage before venting a subsequent increment thereof into said first vessel whereby said gases will be available for reuse.

Claim 55

The process of claim 45 further comprising: cooling each increment of said gaseous reactants in said first vessel before conveying said gas to said second vessel; and separately conveying any condensate in said first vessel to said second vessel.

Claim 56

The process of claim 46 further comprising: cooling each increment of the gaseous reactant and condensate conveyed to said second vessel.

Claim 57

The process of claim 46 whrein said first vessel is a heat exchanger adapted to maintain a cooling medium in a heat transfer relationship with the contents of said vessel said process further comprising: maintaining lignin solvent in a heat transfer relationship with the gaseous contents of said vessel when said contents are incrementally in said first storage vessel so that the gaseous contents of said vessel are cooled as they are conveyed from said vessel to said second storage vessel through said first storage vessel and the lignin solvent is heated.

Claim 58

The process of claim 48 wherein the step of admixing said digested chips with a lignin solvent comprises adding lignin solvent heated in said first storage vessel to said chips in said vessel, and maintaining said chips and solvent under a pressure of at least about 50 p.s.i.g. and at temperature of up to about 250° F. for up to about 30 to 60 minutes before extracting lignin from said digested chips.

Claim 59

The process of claim 34 wherein the step of admixing said digested chips with a lignin solvent comprises: adding said solvent to said digested chips in said vessel and maintaining said chips and solvent under a pressure of at least about 50 p.s.i.g. and a temperature of up to about 250° F. for up to about 30 to 60 minutes before extracting lignin from said digested chips.

Claim 60

A pollution-free process for producing loose cedar wood fibers: providing a vessel; admitting cedar wood chips to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; providing a high speed defibrator; admitting said impregnated chips to said defibrator and defibrating said chips therein to produce a loose cedar wood fibrous material.

Claim 61

A pollution-free process for producing loose cedar wood fibers: providing a vessel; admitting cedar wood chips to said vessel; impregnating said chips in said vessel with an aqueous ammonia solution and sulfur dioxide gas under a pressure of at least 150 p.s.i.g. while maintaining said chips under a vapor dome so that the liquid and gaseous reactants may circulate freely above, below, and on all sides of said chips at a temperature of at least 250° F. for an amount of time of up to about two hours effective to initiate a lignin depolymerizing reaction and form liquid and gaseous by-products; separating said liquid and gaseous reactant by-products from said chips; providing a high speed defibrator; admitting said impregnated chips to said defibrator and defibrating said chips therein to produce a loose cedar wood fibrous material.