Arrangement, system and method for handling non-wood plant material

Patent metadata

Field	Value
Publication number	US-9156221-B2
Application number	US-201314380189-A
Country	US
Kind code	B2
Filing date	Feb 19, 2013
Priority date	Feb 22, 2012
Publication date	Oct 13, 2015
Grant date	Oct 13, 2015

Abstract

A feeding arrangement for feeding plant material to a treatment vessel is disclosed including a plug screw feeder, a force feeding screw for feeding the plant material to the plug screw feeder in which the force feeding screw is arranged essentially perpendicular to the plug screw, and a feeding device for feeding incoming material to the force feeding screw, and in which the plug screw can rotate at variable speed, and the force feeding screw includes when a distance between the last screw thread of the force feeding screw and the outer diameter of the plug screw is up to 90 mm.

First claim

The invention claimed is:

1. A feeding arrangement for feeding non-wood plant material having a bulk density of 40-90 kg/m 3 to a treatment vessel, the feeding arrangement comprising
a plug screw feeder including an inlet section for feeding the plant material to the treatment vessel, the plug screw feeder comprising a plug screw having a longitudinal axis and a corresponding plug screw housing surrounding the plug screw,
a force-feeding screw including a longitudinal axis for feeding the plant material to the plug screw feeder and a corresponding force-feeding screw housing surrounding the force-feeding screw,
the force-feeding screw being arranged to provide the material to the inlet section of the plug screw feeder,
wherein the longitudinal axis of the force-feeding screw is arranged essentially perpendicular to the longitudinal axis of the plug screw, and
a feeding device for feeding incoming material to the force-feeding screw

wherein the plug screw is capable of rotating at variable speed in relation to a production flow rate set by the feeding device, said force-feeding screw including
a distance (D) between an outermost point of a last screw thread, as seen in the direction of the longitudinal axis of the force-feeding screw, the distance (D) between an outermost point of said last screw thread of the force-feeding screw to a point on the outer diameter of the plug screw at the inlet section of the plug screw feeder being up to 90 mm.

2. The feeding arrangement according to claim 1 , wherein the distance (D) is from 10 to 70 mm.

3. The feeding arrangement according to claim 1 , wherein the force-feeding screw is arranged essentially in the same horizontal plane as the plug screw, the force-feeding screw feeding the material to the side of the plug screw.

4. The feeding arrangement according to claim 1 , wherein the force-feeding screw is adapted to be kept at a constant speed, the constant speed being chosen such that the force-feeding screw has a predetermined degree of filling below the maximum degree of filling.

5. The feeding arrangement according to claim 1 , wherein the feeding device is a pin drum feeder.

6. A system for treatment of non-wood plant material, comprising the feeding arrangement of claim 1 and a treatment vessel to which the feeding arrangement is arranged to feed the material to be treated.

7. The system for treatment of non-wood plant material according to claim 6 , wherein the treatment vessel operates at an overpressure of from 4 to 40 bars.

8. The system for treatment of non-wood plant material according to claim 6 , wherein the treatment vessel is a digester.

9. The system for treatment of non-wood plant material according to claim 6 , wherein the treatment vessel is a horizontal reactor.

10. A method for treatment of non-wood plant material using a feeding arrangement according to claim 1 , wherein a distance between an outermost point of the last screw thread of the force-feeding screw, as seen in the direction of the longitudinal axis of the force-feeding screw, to a point on the outer diameter of the plug screw at the inlet section of the plug screw feeder is set to a distance within the interval of from 0 to 90 mm, wherein the feeding device is set to feed a predetermined flow of plant material, and the rotational speed of the plug screw is chosen in relation to the rate of predetermined flow of plant material by the feeding device to the force-feeding screw, such that a predetermined density increase is achieved.

11. The method according to claim 10 , wherein the speed of the force-feeding screw is set at a constant speed, chosen such that the force-feeding screw has a predetermined degree of filling, the predetermined degree of filling being below the maximum degree of filling.

12. The method according to claim 10 , wherein the distance (D) is set at an interval of from 10 to 70 mm.

Assignees

• Valmet Oy

Inventors

• Detlefsen Jan
• Pettersson Patrik
• Wahlberg Robert

Classifications

• D21C7/06 Primary

  Feeding devices · CPC title

• B30B9/16 Primary

  operating with two or more screws or worms · CPC title

• B30B9/127 Primary

  Feed means · CPC title

• D21C5/00

  Other processes for obtaining cellulose, e.g. cooking cotton linters (obtaining fibres for spinning D01C); {Processes characterised by the choice of cellulose-containing starting materials} · CPC title

• D21B1/22

  with screw feed · CPC title