Processes for producing high-yield pulp and paper products

• US 9,556,558 B2
• Filed: 01/06/2015
• Issued: 01/31/2017
• Est. Priority Date: 01/07/2014
• Status: Active Grant

• Current Assignee: GranBio Intellectual Property Holdings, LLC
• Original Assignee: API Intellectual Property Holdings, LLC
• Inventors: Pylkkanen, Vesa, Retsina, Theodora
• Primary Examiner(s): Calandra, Anthony
• Application Number:
  US14/590,681
• Publication Number:
  US 20150191873A1
• Time in Patent Office: 756 Days
• US Class Current: 1/1
• CPC Class Codes: D21B 1/021 by chemical means
• CPC Class Codes: D21C 1/02 with water or steam
• CPC Class Codes: D21C 11/0007 Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for volatile compounds obtained by decomposition of spent liquors in order to regenerate them D21C11/125; compounds obtained by fractionating the liquors in order to regenerate them D21C11/0042
• CPC Class Codes: D21C 11/0042 Fractionating or concentration of spent liquors by special methods concentration by evaporation D21C11/10
• CPC Class Codes: D21C 11/10 Concentrating spent liquor by evaporation evaporators B01D
• CPC Class Codes: D21C 9/02 Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
• CPC Class Codes: D21H 11/08 Mechanical or thermomechanical pulp

Abstract

An improved semichemical pulping process is disclosed to reduce washing costs and recovery process costs, while producing equivalent pulp and paper products. In some variations, the invention provides a process for producing a paper product from biomass, comprising: digesting lignocellulosic biomass in the presence of steam and/or hot water to generate an intermediate pulp material and a liquid phase containing extracted hemicelluloses; mechanically refining the intermediate pulp material, to generate a refined pulp material; and introducing the refined pulp material, the liquid phase, and optionally a separate solid material to a paper machine, to produce a paper product. The process optionally employs no washing step. When the liquid phase is washed from the intermediate pulp material or the refined pulp material using an aqueous wash solution, the wash filtrate may be introduced directly or indirectly to the paper machine.

Claims

1. A process for producing a paper product from biomass, said process comprising:

(a) providing lignocellulosic biomass comprising cellulose, hemicellulose, and lignin;

(b) digesting said biomass in the presence of steam and/or hot water to generate an intermediate pulp material and a liquid phase, wherein said liquid phase contains extracted hemicelluloses and lignin;

(c) evaporating said liquid phase to remove volatile components, thereby generating a solids-enriched liquid phase;

(d) mechanically refining said intermediate pulp material, to generate a refined pulp material; and

(e) introducing said refined pulp material, said solids-enriched liquid phase, and optionally a separate solid material to a paper machine, to produce a paper product,

wherein said process further comprises washing said liquid phase from said intermediate pulp material using an aqueous wash solution, to generate an intermediate pulp material wash filtrate, and evaporating said intermediate pulp material wash filtrate to remove volatile components, thereby generating a solids-enriched intermediate pulp material wash filtrate;

wherein said solids-enriched intermediate pulp material wash filtrate is introduced to said paper machine.

2. The process of claim 1, wherein step (b) is conducted using said steam in saturated, superheated, or supersaturated form.

3. The process of claim 1, wherein step (b) is conducted using hot water.

4. The process of claim 1, wherein step (b) is conducted at a digestor temperature selected from about 140°

C. to about 220°

C.

5. The process of claim 1, wherein step (b) is conducted at a digestor residence time selected from about 1 minute to about 60 minutes.

6. The process of claim 1, wherein said refined pulp material is not separately washed.

7. A process for producing a paper product from biomass, said process comprising:

(a) providing lignocellulosic biomass comprising cellulose, hemicellulose, and lignin;

(b) digesting said biomass in the presence of steam and/or hot water to generate an intermediate pulp material and a liquid phase, wherein said liquid phase contains extracted hemicelluloses and lignin;

(c) evaporating said liquid phase to remove volatile components, thereby generating a solids-enriched liquid phase;

(d) mechanically refining said intermediate pulp material, to generate a refined pulp material; and

(e) introducing said refined pulp material, said solids-enriched liquid phase, and optionally a separate solid material to a paper machine, to produce a paper product,

wherein said process further comprises washing said liquid phase from said refined pulp material using an aqueous wash solution, to generate a refined pulp material wash filtrate, and evaporating said refined pulp material wash filtrate to remove volatile components, thereby generating a solids-enriched refined pulp material wash filtrate;

wherein said solids-enriched refined pulp material wash filtrate is introduced to said paper machine.

8. The process of claim 7, wherein step (b) is conducted using said steam in saturated, superheated, or supersaturated form.

9. The process of claim 7, wherein step (b) is conducted using hot water.

10. The process of claim 7, wherein step (b) is conducted at a digestor temperature selected from about 140°

C. to about 220°

C.

11. The process of claim 7, wherein step (b) is conducted at a digestor residence time selected from about 1 minute to about 60 minutes.

12. The process of claim 7, wherein said intermediate pulp material is not separately washed.