ARRANGEMENT AND SYSTEM FOR A TREATMENT PROCESS

Abstract

A system for feeding lignocellulosic biomass material, comprising a pre-compressing stage for receiving biomass material and pre-compressing the material at a first pressure and a first compression ratio. A plug screw feeder receives the pre-compressed material and feeds the material against a second pressure and a second compression ratio, wherein the plug screw feeder includes a variable speed plug screw arranged in the plug screw feeder connected to a variable speed plug screw power source.

Claims

1. A system for feeding lignocellulosic biomass material, comprising: a pre-compressing stage for receiving biomass material and pre-compressing the material at a first pressure and a first compression ratio; a plug screw feeder for receiving the pre-compressed material and feeding the material against a second pressure and a second compression ratio, said plug screw feeder including a variable speed plug screw arranged in the plug screw feeder connected to a variable speed plug screw power source; and wherein the first compression ratio in the pre-compression stage is between >1 and <2 and the second compression ratio in the plug screw feeder is between 1-5.

2. The system according to claim 1, wherein the pre-compression stage is a force feed screw including a force feed cylinder and a variable speed force feed screw arranged in the force feed cylinder, wherein a control arrangement controls the speed of the rotation of the variable speed force feed screw to a first RPM.

3. The system according to claim 2, wherein said control arrangement controls the speed of the rotation of the variable speed plug screw to a second RPM.

4. The system according to claim 2, wherein the first compression ratio in the force feed screw is in a range between >1 and <2, or in a range between 1-1.5 or preferably in a range between 1.05-1.4.

5. The system according to claim 1, wherein the second compression ratio in the plug screw feeder is in a range of 1-5, or in a range between 3-4, 5 or in a range between 1-2,5, or substantially equal to 1.

6. The system according to claim 2, wherein a bulk density of biomass material entering the force feed screw is in a range of 110-200 kg/m.sup.3 or in a range between 120-150 kg/m.sup.3.

7. The system according to claim 1, wherein the biomass material is powder material, granular material and/or steam exploded material.

8. The system according to claim 1, where the system is used in a pulping process.

9. A method for feeding lignocellulosic biomass material, comprising: pre-compressing biomass material at a first pressure and a first compression ratio in a pre-compression stage; applying a second pressure on receiving the pre-compressed material and feeding the material against a second pressure and a second compression ratio in a second pressure applying stage, and wherein the first compression ratio in the pre-compression stage is between >1 and <2 and the second compression ratio in lower the plug screw feeder is between 1-5.

10. The method according to claim 9, wherein the first compression ratio in the pre-compression stage is in a range between >1 and <2, or in a range between 1-1.5 or preferably in a range between 1.05-1.4.

11. The method according to claim 9, wherein the second compression ratio in the second pressure applying stage is in a range between 1-5, or in a range between 3-4, 5 or in a range between 1-2, 5, or substantially equal to 1.

12. The method according to claim 9, wherein a bulk density of biomass material entering the pre-compression stage is in a range of 110-200 kg/m.sup.3 or in a range between 120-150 kg/m.sup.3.

13. The method according to claim 9, wherein the biomass material is powder material, granular material and/or steam exploded material.

14. The system according to claim 9, wherein the method is used in a pulping process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will now be described, for exemplary purposes, in more detail by way of embodiments and with reference to the enclosed drawings, in which:

[0027] FIG. 1 is a schematic view of a feeding system according to an embodiment of the present invention; and

[0028] FIG. 2 is a schematic view of a method for feeding according to an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0029] For the purpose of this disclosure, the term longitudinal refers to the direction along which a body, part or element has its greatest extension. Further, when the term longitudinal is used in connection with the axes of screws, the longitudinal axis corresponds to the rotational axis of the screw.

[0030] With reference first to FIG. 1, an embodiment of the system according to the present invention will be discussed.

[0031] FIG. 1 is a schematic block diagram of a system 10 for biomass treatment according to an embodiment of the present invention. The lignocellulosic biomass 12 may be treated in different processes, such as a soaking process, before feeding the biomass material to the storage vessel, bin or silo 11. The biomass material may be, for example, granular like biomass material such as wood chips, powder like material, or steam exploded material with high bulk density and low network strength based on wood chips of softwood or hardwood, sawdust, grasses, straw, bagasse, kenaf, or other forms of agricultural waste or a combination thereof.

[0032] A pre-compression stage 2 receives the biomass material and executes a pre-compression by applying a first pressure P.sub.1. In preferred embodiments, the pre-compression stage is a longitudinally arranged force feed screw 2. The force feed screw 2 includes a force feed cylinder 3 and a variable speed force feed screw 4 arranged in the force feed cylinder 3. A control arrangement 5 controls the speed of the rotation of the variable speed force feed screw 2 to a first RPM, RPM.sub.1. In other embodiments of the present invention, the pre-compression stage includes one or several plug screws with low compression degree, a vertical chute or a piston feeding.

[0033] The force feed screw 2 is operatively connected to a longitudinally arranged plug screw feeder 6 for receiving the pre-compressed biomass material and feeding the material against a second pressure P.sub.2. The plug screw feeder 6 includes a variable speed plug screw 7 arranged in the plug screw feeder 6 and is connected to the control arrangement including a variable speed plug screw power source, and wherein the control arrangement 5 controls the speed of the rotation of the variable speed plug screw 7 to a second RPM, RPM.sub.2. The plug screw feeder 6 also includes a blow back damper 9.

[0034] A first density compression ratio produced by the force feed screw is in a range between 1:1 (>1) and below 2:1 (<2), or in a range between 1:1-1.5:1 or >1:1-1.5:1, or 1.001:1-1.5:1, or 1.01:1-1.5:1, or 1.1:1-1.5:1, or preferably in a range between 1.05-1.4 (1.05:1-1.4:1), and a second density compression ratio produced by the plug screw feeder is in a range of 1:1-5:1, or 1.001:1-5:1, or 1.01:1-5:1, or 1.1:1-5:1. or in a range between 1:1-4.5:1, or 1.001:1-4.5:1, or 1.01:1-4.5:1, or 1.1:1-4.5:1, or in a range between 2-4.5, or 2.001:1-4.5:1, or 2.01:1-4.5:1, or 2.1:1-4.5:1. or in a range of 3-4,5 or 3.001:1-4.5:1, or 3.01:1-4.5:1, or 3.1:1-4.5:1, or in a range between 1-2,5, or 1.001:1-2.5:1, or 1.01:1-2.5:1, or 1.1:1-2.5:1, or substantially equal to 1.

[0035] A bulk density of the biomass material entering the force feed screw 2 is in a range of 110-200 kg/m.sup.3 or in a range between 120-150 kg/m.sup.3.

[0036] The system according to the present invention may be used in a pulping process or a process for producing bio-fuels.

[0037] The plug screw feeder 6 may further be operatively connected to downstream processing steps 14 such as, for example, a reactor stage 14 wherein steam 11, e.g. high pressure steam at a pressure of about 650-4000 kPa or low-pressure steam at a pressure of about 90-1200 kPa, may be added via a valve 16.

[0038] FIG. 2 is a schematic block diagram of a method 20 for biomass treatment according to an embodiment of the present invention. The lignocellulosic biomass 12 may be treated in different processes, such as a soaking process, before feeding the biomass material to the storage vessel, bin or silo. The biomass material may be, for example, granular like biomass material such as wood chips, powder like material, or steam exploded material with high bulk density and low network strength based on wood chips of softwood or hardwood, sawdust, grasses, straw, bagasse, kenaf, or other forms of agricultural waste or a combination thereof.

[0039] First, a pre-compression 22 is performed using a pre-compression stage 2 by applying a first pressure P.sub.1 and a first compression ratio. In preferred embodiments, the pre-compression stage is a longitudinally arranged force feed screw 2.

[0040] Then, a second pressure applying step 24 is performed using a longitudinally arranged plug screw feeder 6 for receiving the pre-compressed biomass material and feeding the material against a second pressure P.sub.2 and a second compression ratio.

[0041] The first compression ratio in the pre-compression step 22 may, depending on the specific material used, be higher, lower or substantially equal to the second compression ratio in the second pressure applying step 24. A first compression ratio in the force feed screw is in a range between 1:1 (>1) and below 2:1 (<2), or in a range between 1:1-1.5:1 or >1:1-1.5:1, or 1.001:1-1.5:1, or 1.01:1-1.5:1, or 1.1:1-1.5:1, or preferably in a range between 1.05-1.4 (1.05:1-1.4:1), and a second compression ratio in the plug screw feeder is in a range of 1:1-5:1, or 1.001:1-5:1, or 1.01:1-5:1, or 1.1:1-5:1. or in a range between 1:1-4.5:1, or 1.001:1-4.5:1, or 1.01:1-4.5:1, or 1.1:1-4.5:1, or in a range between 2-4.5, or 2.001:1-4.5:1, or 2.01:1-4.5:1, or 2.1:1-4.5:1, or in a range of 3-4,5 or 3.001:1-4.5:1, or 3.01:1-4.5:1, or 3.1:1-4.5:1, or in a range between 1-2,5, or 1.001:1-2.5:1, or 1.01:1-2.5:1, or 1.1:1-2.5:1, or substantially equal to 1.

[0042] A bulk density of the biomass material entering the pre-compression step 22 is in a range of 110-200 kg/m.sup.3 or in a range between 120-150 kg/m.sup.3.

[0043] The method according to the present invention may be used in a pulping process or a process for producing bio-fuels.

[0044] The second pressure applying step 24 may feed the biomass material downstream processing steps 26 such as, for example, a reactor stage 14 wherein steam 11, e.g. high pressure steam at a pressure of about 650-4000 kPa or low-pressure steam at a pressure of about 90-1200 kPa, may be added.

[0045] The invention shall not be considered limited to the embodiments illustrated, but can be modified and altered in many ways by one skilled in the art, without departing from the scope of the appended claims.