Methods and devices for hydrothermal pretreatment of lignocellulosic biomass

• US 10,513,823 B2
• Filed: 11/12/2014
• Issued: 12/24/2019
• Est. Priority Date: 05/13/2014
• Status: Active Grant

• Current Assignee: TAB Holding APS
• Original Assignee: Biofuel Technology A/S
• Inventors: Juhl Fons, Mogens, Bonde, Torben
• Primary Examiner(s): Drodge, Joseph W
• Application Number:
  US15/310,606
• Publication Number:
  US 20170101737A1
• Time in Patent Office: 1,868 Days
• Field of Search: 127 1, 127 36, 127 37, 422112, 422129, 422241, 536 56, 536124, 536127, 536128
• CPC Class Codes: B01J 19/006 Baffles
• CPC Class Codes: B01J 19/24 Stationary reactors without moving elements inside B01J19/08, B01J19/26 take precedence; with stationary particles B01J8/02
• CPC Class Codes: B01J 3/04 Pressure vessels, e.g. autoclaves
• CPC Class Codes: B01J 4/005 provided with baffles
• CPC Class Codes: C08H 8/00 Macromolecular compounds derived from lignocellulosic materials pretreatment thereof B27N
• CPC Class Codes: C12P 2201/00 Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
• 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 7/06 Feeding devices
• CPC Class Codes: D21C 7/12 Devices for regulating or controlling
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

Methods and devices are provided for hydrothermal pretreatment of lignocellulosic biomass. A mechanically simple and inexpensive vertical steam reactor is fed with biomass feedstock from the top, while pretreated material is removed from the bottom in steady-state by operation of moveable upper and lower restrictor means, which project across the reactor cross section when engaged. The vertical column of biomass is supported by the upper restrictor means. This is periodically withdrawn from the reactor cross section, permitting the column of biomass to fall by force of gravity onto the lower restrictor means. The upper restrictor means is then re-inserted, after which the lower restrictor means is withdrawn permitting a “plug” of pretreated material to be removed by force of gravity. Using biomass feedstock that has been compressed in a reciprocating piston press to bulk density of at least 500 kg/m3, which can be fed dry into the reactor using simple, inexpensive sluice systems and then wetted inside the reactor, this system provides comparable biomass throughput at a fraction of the cost of traditional commercial hydrothermal pretreatment systems used in “second generation” biorefining.

Claims

1. An apparatus for hydrothermal pretreatment of lignocellulosic biomass comprising:

a substantially vertical reactor vessel, pressure resistant to between 4 and 23 bar and having an upper part, a lower part, a biomass inlet situated in the upper part, a biomass outlet situated in the lower part, and one or more steam inlets; and

upper and lower restrictor means situated in the lower part of the substantially vertical reactor vessel and which are moveable between a retracted position in which the upper and lower restrictor means do not occlude passage of biomass through the substantially vertical reactor vessel and an engaged position in which the upper and lower restrictor means occlude the passage of biomass by forming a physical obstruction across a cross section of the substantially vertical reactor vessel;

wherein said upper restrictor means comprises a series of parallel spears having a generally cylindrical shape and tips which project into a cross section of the substantially vertical reactor vessel.

2. The apparatus of claim 1 further comprising a substantially vertical biomass inlet sluice vessel situated above the substantially vertical reactor vessel and in which the biomass inlet comprises an inlet valve.

3. The apparatus of claim 2 in which the biomass inlet sluice vessel is in communication with a biomass feedstock input conveyor.

4. The apparatus of claim 1 further comprising a substantially vertical biomass outlet sluice vessel situated beneath the substantially vertical reactor vessel and in which the biomass outlet comprises an outlet valve.

5. The apparatus of claim 1 further comprising means for injecting pressurised hot water situated in the upper part of the substantially vertical reactor vessel.

6. The apparatus of claim 1 in which the upper and lower restrictor means and their drive mechanism is situated within a readily removable appendix vessel pressure resistant to between 4 and 23 bar.

7. A method for hydrothermal pretreatment of lignocellulosic biomass comprising the steps of:

introducing biomass feedstock through an inlet situated in an upper part of a substantially vertical, pressurised reactor vessel in which steam pressure is maintained between 4 and 23 bar so as to maintain temperature at a level between 150-220°

C. and which is fitted with upper and lower restrictor means in a lower part of the substantially vertical, pressurized reactor vessel, in such manner that incoming feedstock biomass lands on top of a column of biomass introduced previously that is supported inside the reactor by the upper restrictor means, said upper restrictor means comprises a series of parallel spears having generally cylindrical shape and tips which project into a cross section of the substantially vertical pressurized, reactor vessel, followed by

retracting the upper restrictor means to permit the column of biomass to fall downwardly to be supported by the lower restrictor means, followed by

re-inserting the upper restrictor means through the column of biomass so as to support the column of biomass above the upper restrictor means, followed by

retracting the lower restrictor means to permit a quantity of biomass that was supported by the lower restrictor means to fall downwardly to an outlet situated in the lower part of the reactor vessel.

8. The method of claim 7 comprising a steady-state introduction of the feedstock through the inlet and removal of the biomass through the outlet.

9. The method of claim 7 wherein biomass is introduced into the pressurised reactor vessel by a method comprising the steps of:

introducing biomass feedstock into a substantially vertical sluice vessel situated above the substantially vertical pressurised reactor vessel, followed by pressurisation of the sluice vessel to a pressure that is near or equal to reactor pressure, and

opening an inlet valve situated in the upper part of the reactor vessel and introducing the biomass feedstock into the pressurised reactor vessel by gravity causing the biomass to fall from the sluice vessel through the open inlet valve.

10. The method of claim 7 wherein pretreated biomass is removed from the pressurised reactor vessel by a method comprising the steps of:

opening an outlet valve situated in the bottom of a substantially vertical pressurised reactor vessel and allowing pretreated biomass to fall by force of gravity through the open reactor outlet valve at reactor pressure into a substantially vertical sluice vessel situated below the reactor, followed by

closing the reactor outlet valve and de-pressurising the sluice vessel to a pressure that is near or equal to ambient, followed by

opening an outlet valve situated at the bottom of the sluice vessel and removing pre-treated biomass by action of gravity causing the material to fall through the open sluice outlet valve.

11. The method of claim 7 in which the biomass feedstock comprises feedstock pre-processed by mechanical compression using repeated compression in a reciprocating piston press to bulk density of at least 500 kg/m³.

12. The method of claim 11 in which water content of the biomass feedstock is adjusted within the pressurised reactor by introduction of pressurised liquid water.

13. The method of claim 12 in which water content of the biomass feedstock is adjusted within the pressurised reactor by introduction of pressurised liquid water to final levels which, including condensation associated with heating the biomass, are greater than 40% by weight.

14. The method of claim 7 wherein the upper and lower restrictor means and their drive mechanism is situated within a readily removable appendix vessel pressure resistant to between 4 and 23 bar.