Process for producing dried, singulated fibers using steam and heated air

• US 7,334,347 B2
• Filed: 08/20/2004
• Issued: 02/26/2008
• Est. Priority Date: 10/30/2001
• Status: Expired due to Fees

• Current Assignee: Weyerhaeuser NR Company (Weyerhauser)
• Original Assignee: Weyerhaeuser Company (Weyerhauser)
• Inventors: Tveter, Christopher Q., Mann, Christopher A.
• Primary Examiner(s): Rinehart; Kenneth
• Assistant Examiner(s): NGUYEN, CAMTU TRAN
• Application Number:
  US10/923,447
• Publication Number:
  US 20050086828A1
• Time in Patent Office: 1,285 Days
• Field of Search: 344/43, 343/26, 342/21, 34/83, 343/59, 344/13, 604/374, 604/367, 162/55, 162/65, 162/63
• US Class Current: 34/359
• CPC Class Codes: C04B 18/241 Paper, e.g. waste paper; Paper pulp
• CPC Class Codes: D21C 9/001 Modification of pulp properties purification D21C9/08
• CPC Class Codes: D21C 9/002 by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
• CPC Class Codes: D21C 9/007 by mechanical or physical means
• CPC Class Codes: D21C 9/18 De-watering de-watering in general F26B; Elimination of cooking or pulp-treating liquors from the pulpD21C9/002, D21C9/02 take precedence; paper-making machines D21F; strainers in digesters D21C7/00; presses in general B30B
• CPC Class Codes: D21C 9/185 comprising at least one step where the pulp is suspended in a gaseous medium, e.g. flash drying
• CPC Class Codes: D21H 11/20 Chemically or biochemically modified fibres
• CPC Class Codes: D21H 15/04 crimped, kinked, curled or twisted fibres
• CPC Class Codes: D21H 17/38 containing crosslinkable groups
• CPC Class Codes: D21H 17/63 Inorganic compounds
• CPC Class Codes: D21H 23/04 Addition to the pulp; After-treatment of added substances in the pulp
• CPC Class Codes: D21H 27/08 Filter paper self-supporting filtering material B01D39/14; making on paper-making machines D21F11/14
• CPC Class Codes: F26B 17/105 the shaft or duct, e.g. its axis, being other than straight, i.e. curved, zig-zag, closed-loop, spiral
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

Dried, singulated cellulose pulp fiber is produced by introducing wet pulp steam and air into a jet dryer. The air is heated to a temperature of 250° C. to 600° C. Steam is injected at a nozzle pressure of from 344 KPa (50 psig) to 4,137 KPa (600 psig). The pulp is removed from the jet dryer and separated from the air. The product formed has advantageous properties such as low fines count, improved kink curl and twist, and high permeability.

Claims

1. A process for producing singulated pulp fibers, comprising:

introducing a never-dried, wet pulp, and air into a jet dryer that recirculates said pulp in a loop;

heating said air prior to introduction into said dryer to a temperature of from about 250°

C. to about 600°

C.;

injecting steam at a pressure of from 344 KPa (50 psig) to about 4,137 KPa (600 psig) into said jet dryer along with said wet pulp, and removing said pulp from said jet dryer and separating said pulp fibers from said air.

2. The process of claim 1, wherein said steam is injected at a pressure ranging from about 688 KPa (100 psig) to 2,758 KPa (400 psig).

3. The process of claim 1, wherein said steam is injected at a pressure of from about 896 KPa (130 psig) to 2,068 KPa (300 psig).

4. The process of claim 1, wherein said inlet temperature ranges from about 300°

C. to about 400°

C.

5. The process of claim 1, wherein the consistency of said wet pulp ranges from about 30% to about 40%.

6. The process of claim 1, wherein the manifold pressure of said air when introduced into said jet dryer ranges from about 1.4 KPa (2 psig) to about 103.5 KPa (15 psig).

7. The process of the claim 6, wherein said air is introduced at a pressure of about 20.7 KPa (3 psig) to about 34.5 KPa (5 psig).

8. The process of claim 1, wherein the outlet temperature of said pulp from said jet dryer ranges from about 110°

C. to about 200°

C.