Rapid production of hydrothermally carbonized biomass via reactive twin-screw extrusion

• US 10,442,995 B2
• Filed: 03/17/2014
• Issued: 10/15/2019
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Gas Technology Institute (GTI Energy)
• Original Assignee: Gas Technology Institute (GTI Energy)
• Inventors: Felix, Larry G., Farthing, William E., Irvin, James H., Snyder, Todd R., Yan, Wei
• Primary Examiner(s): Warden, Jill A
• Assistant Examiner(s): Handy, Dwayne K
• Application Number:
  US14/216,028
• Publication Number:
  US 20140262727A1
• Time in Patent Office: 2,038 Days
• CPC Class Codes: B29C 2948/92704 Temperature
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/268 Throttling of the flow, e.g. for cooperating with plasticising elements or for degassing flow control means B29C48/255
• CPC Class Codes: B29C 48/40 using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders
• CPC Class Codes: B29C 48/402 the screws having intermeshing parts
• CPC Class Codes: B29C 48/67 having incorporated mixing devices not provided for in groups B29C48/52 - B29C48/66
• CPC Class Codes: B29C 48/832 Heating
• CPC Class Codes: B29C 48/834 Cooling
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• CPC Class Codes: C10B 7/10 with conveyor-screws
• CPC Class Codes: C10L 9/086 Hydrothermal carbonization

Abstract

A system for the production of carbonized biomass that includes an infeed for accepting biomass feed material and an associated twin screw extruder. A water heater is connected with respect to at least one inlet along a length of the twin screw extruder and a pressure sustaining valve is connected at an outlet of the twin screw extruder.

Claims

1. A system for the production of hydrothermally carbonized biomass comprising:

an infeed for accepting biomass feed material;

a twin screw extruder connected with respect to the infeed, the twin screw extruder having a length between the infeed and an outlet;

a water heater having a volume of hot water at 230-300°

C. connected with respect to at least one inlet within a reactor section along the length of the twin screw extruder, wherein the at least one inlet generally corresponds with a pressure boundary within the twin screw extruder; and

a pressure sustaining valve connected at the outlet, wherein the valve opens to allow the hydrothermally carbonized biomass through the outlet, and the valve closes to maintain a pressure and temperature within the twin screw extruder, wherein the valve comprises a spring-loaded valve plunger over or within the outlet, wherein the valve plunger is adjustably preloaded by tightening a calibrated handwheel to a predetermined setting.

2. The system of claim 1 wherein the twin screw extruder includes a plurality of mixing elements and a plurality of reversing elements.

3. The system of claim 2 wherein the reversing elements are interspersed within the twin screw extruder to provide flow restrictions and/or pressure boundaries within the twin screw extruder.

4. The system of claim 1 wherein the twin screw extruder includes at least one reversing element and an increasing pitch on a mixing element between the infeed and the at least one reversing element.

5. The system of claim 1 wherein the liquid water inlet is positioned immediately following a first dynamic seal created between a mixing element and a reversing element within the twin screw extruder.

6. The system of claim 1 wherein the twin screw extruder includes an increasing pitch mixing element extending from the infeed.

7. The system of claim 1 wherein at least three reversing elements are positioned within the twin screw extruder resulting in at least three flow restrictions and/or pressure boundaries.

8. The system of claim 1 wherein the pressure sustaining valve includes a handwheel to adjust a desired pressure within the twin screw extruder.

9. The system of claim 1 wherein the pressure sustaining valve is regulated by a servo-actuated feedback-control system that uses pressure and temperature measurements within a reaction section of the twin-screw extruder to stabilize a pressure within the reaction section.

10. The system of claim 9 wherein the feedback-control system stabilizes pressure within the reaction section to within 5% to 10% of a process average value ranging between 25 and 100 bar.

11. The system of claim 1 wherein the pressure sustaining valve is regulated by a servo-actuated feedback-control system that uses pressure and temperature measurements within a reaction section of the twin-screw extruder to maintain an average Specific Mechanical Energy of the twin-screw extruder to a desired value.

12. The system of claim 11 wherein the desired value is within 5% of a process average value ranging between 20 and 80 Watt-hours/kilogram.

13. The system of claim 1 wherein the twin screw extruder comprises a plurality of aligned barrels, each barrel having a band heater.

14. The system of claim 1 further comprising a mixing section, wherein hydrothermally carbonized biomass exiting the system is directed to the mixing section where biomass prepared for forming is mixed with hydrothermally carbonized biomass and a resulting mixture is pelletized or briquetted.

15. The system of claim 1 further comprising a mixing section, wherein hydrothermally carbonized biomass exiting the system is directed to the mixing section where torrefied biomass is mixed with hydrothermally carbonized biomass and the resulting mixture is pelletized or briquetted.

16. The system of claim 1 wherein the valve opens the outlet and controls and maintains upstream pressure maintained in a reactor section of the twin screw extruder.

17. The system of claim 1 wherein the valve maintains a quasi-steady-state process within the twin screw extruder while controlling the delivery of the hydrothermally carbonized biomass through the outlet.

18. The system of claim 17, further comprising a control system in opening and closing combination with the valve, wherein the control system monitors resistance within the twin screw extruder to maintain a constant product discharge through the outlet.

19. A system for the production of hydrothermally carbonized biomass comprising:

a supply of lignocellulosic biomass feed material;

an infeed for accepting the lignocellulosic biomass feed material;

a twin screw extruder connected with respect to the infeed, the twin screw extruder having a length between the infeed and an outlet;

an high-pressure, high-temperature, on-demand hot water heater adapted to provide hot water at greater than 230°

C. connected with respect to at least one inlet within a reactor section along the length of the twin screw extruder, wherein the at least one inlet generally corresponds with a pressure boundary within the twin screw extruder; and

a pressure sustaining valve closing or covering the outlet, wherein the hydrothermally carbonized biomass is provided through the outlet upon an opening of the valve under pressure from within the twin screw extruder, wherein the valve comprises a spring-loaded valve plunger over or within the outlet, wherein the valve plunger is adjustably preloaded by tightening a calibrated handwheel to a predetermined setting.