Method And A System For The Pretreatment Of Lignocellulosic Material

• US 20100216202A1
• Filed: 07/24/2008
• Published: 08/26/2010
• Est. Priority Date: 07/25/2007
• Status: Active Grant

• Current Assignee: Haarslev A/S (HL Industries A/S)
• Original Assignee: Haarslev A/S (HL Industries A/S)
• Inventors: Hansen, Palle, Fosbol, Peder
• Granted Patent: US 8,932,467 B2
• Time in Patent Office: Days
• US Class Current: 435/165
• CPC Class Codes: C13K 1/02 obtained by saccharification of cellulosic materials manufacture of fodder A23K10/32
• CPC Class Codes: C13K 1/04 Purifying
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

The invention relates to a method and a system for the pretreatment of lignocellulosic material by thermal hydrolysis, in particular with a view to producing bioethenol, wherein the material is first admixed with water and is then passed to a reactor, in which the soaked material is subjected to a high temperature and a high pressure to such an extent that is it accessible for a subsequent treatment with enzymes, following which the treated material is separated into liquid part and a solid part, where the solid component is subsequently used for the production of bioethenol and enzymation and fermentation. Exclusively steam is used in the method and the corresponding system for heating, stirring and transport, as e.g. the transport through the various elements of the system is provided by a pressure difference between the compartments of the elements. The material (32) is discharged to an economizer (4), in which a separator (5) separates the material into a solid part and a liquid part. The solid part (29) is discharged for use in the further process. The method is performed as a two step proceed, as the material (32) from the first reactor (3) is injected into the economizer (4) and from there further on (26) to an additional reactor (8) for an additional treatment step. A high efficiency is achieved, as all pressures are established by direct steam addition, and heating surfaces and mechanical elements, such as pumps, stirrers, stuffing boxes, bearings, etc. are avoided. The use of economizers (4, 9) improves the consumption of energy relative to previously known processes.

Claims

1. A method of pretreating lignocellulosic material by thermal hydrolysis, in particular with a view to producing bioethanol, wherein the material is first admixed with water and/or aqueous liquid and is then passed to a reactor, in which the soaked material is subjected to a high temperature and a high pressure to such an extent that it is accessible for a subsequent treatment with enzymes, following which the treated material is separated into a liquid part and a solid part, wherein the liquid and solid parts may subsequently be used for the production of bioenthanol by enzymation and fermentation, characterized in that exclusively steam is used in the heating, stirring and transport of the material through the steps of the retreatment, where all transport is established by pressure differences, wherein the material (30) is admixed with water or aqueous liquid and is passed to the reactor (3) through a gate (2), which may be closed, following which steam (31) is supplied to the gate (2) at a pressure which is higher than the pressure in the reactor (3), following which the material in the reactor is subjected to steam (17, 26) which is introduced through nozzles, optionally at several levels, following which the finished material separated into a solid part (22, 29) and a liquid part (21, 28) in a separator (5), and wherein the solid part of discharged for further treatment, while the liquid phase is optionally collected or recirculated.

2. A method according to claim 1, characterized in that the separation takes place in an economizer (4) in which the pressure is lower than the pressure in the reactor (3).

3. A method according to claim 2, characterized in that the waste steam (16, 34, 36) from the economizer (4, 9) is passed to the gate (2) and the economizer (9) after the discharge of the solid part.

4. A method according to claim 2, characterized in that the material is passed from the reactor (3) to an oxidation reactor (7) and from there to the economizer (4), and that the pressure in the oxidation reactor (7) is kept lower than the pressure in the reactor (3), respectively the pressure in the economizer (4) is kept lower than the pressure in the oxidation reactor (7),

5. A method according to claim 2, characterized in that the pretreatment takes place in two steps, as the solid part (24) from the economizer (4) is transported to an additional reactor (8) and is treated in this, following which it is passed to an additional economizer (9) from which it is discharged for further treatment, and that the pressure in the additional reactor (8) is lower than the pressure in the economizer (4), respectively the pressure in the additional economizer (9) is lower than the pressure in the additional reactor (8), such that the material may be transported solely by the pressure differences,

6. A method according to claim 5, characterized in that oxygen is added to the additional reactor (8) or to an oxidation reactor between the additional reactor (8) and the additional economizer (9).

7. A system for pretreating lignocellulosic material by thermal hydrolysis, in particular with a view to producing bioethanol comprising, in sequence, means for adding water and/or aqueous liquid to the material (15, 30), a gate (2), at least one reactor (3) which may be closed off from the gate (2), means for supplying steam (17, 26) at a high pressure and at a high temperature to the reactor through nozzles, optionally at several levels, one economizer (4), a separator (5) in the economizer for separating the material into a solid part and a liquid part, and means for discharging the solid part (27), wherein the pressure conditions in these elements constantly decrease in said sequence, and wherein transport or discharge takes place solely by the pressure difference between the individual elements.

8. A system according to claim 7, characterized in that it additionally comprises an additional reactor (8) and an additional economizer (9) arranged in sequence after the economizer (4).

9. A system according to claim 7, characterized in that it additionally comprises an oxidation reactor (7) arranged after the reactor (3).

10. A system according to claim 7, characterized in that it additionally comprises a vacuum cooler (13) for cooling the solid (27) and recovering energy in the form of flash steam (29).

11. A system according to claim 8, characterized in that it additionally comprises an oxidation reactor (7) arranged after the additional reactor (8).