Slurry drying plant, a method for drying slurry and use of a slurry drying plant

Patent metadata

Field	Value
Publication number	US-12078416-B2
Application number	US-201817289540-A
Country	US
Kind code	B2
Filing date	Nov 1, 2018
Priority date	Nov 1, 2018
Publication date	Sep 3, 2024
Grant date	Sep 3, 2024

Abstract

Disclosed is a slurry drying plant ( 1 ) comprising a slurry extruder ( 3 ) including a slurry inlet ( 2 ) and conveying means ( 4 ) arranged to convey the slurry through the slurry extruder ( 3 ) and force the slurry out of a plurality of exit openings ( 5 ) of the slurry extruder ( 3 ) to form a plurality of slurry strings ( 7 ), wherein the slurry strings ( 7 ) are forced out into a drying chamber ( 8 ) in which the plurality of slurry strings ( 7 ) is dried. The slurry drying plant ( 1 ) further comprises slurry heating means ( 6 ) comprising flow means for passing superheated steam past the slurry strings ( 7 ) in the drying chamber ( 8 ), and inlet pressure detection means ( 9 ) for detecting a slurry inlet pressure at the slurry inlet ( 2 ). The slurry drying plant ( 1 ) also comprises control means ( 17 ) arranged to control the conveying speed of the conveying means ( 4 ) in response to the slurry inlet pressure. Furthermore, a method for drying slurry and use of a slurry drying plant ( 1 ) is disclosed.

First claim

The invention claimed is:

1. A slurry drying plant comprising
a slurry extruder including a slurry inlet and conveyer arranged to convey said slurry through said slurry extruder and force said slurry out of a plurality of exit openings of said slurry extruder to form a plurality of slurry strings, wherein said slurry strings are forced out into
a drying chamber in which said plurality of slurry strings are dried,
wherein said slurry drying plant further comprises slurry heater comprising flow generator for passing superheated steam past said slurry strings in said drying chamber, and inlet pressure detector for detecting a slurry inlet pressure at said slurry inlet and
wherein said slurry drying plant also comprises a controller arranged to control the conveying speed of said conveyer in response to said slurry inlet pressure.

2. A slurry drying plant according to claim 1 , wherein said flow generator is arranged to guide said superheated steam flow past said slurry strings substantially in the same direction as the slurry strings are extruded.

3. A slurry drying plant according to claim 1 , wherein said drying plant comprises a slurry tank and a slurry conduit arranged to guide said slurry from said slurry tank to said slurry inlet.

4. A slurry drying plant according to claim 3 , wherein said slurry tank is arranged above said slurry inlet so that said slurry is guided through said slurry conduit by means of gravity.

5. A slurry drying plant according to claim 3 , wherein said inlet pressure detector comprises a level meter arranged to detect a slurry level in said slurry tank.

6. A slurry drying plant according to claim 1 , wherein said controller is arranged to control said slurry heater in response to said slurry inlet pressure and/or said conveying speed of said conveyer.

7. A slurry drying plant according to claim 1 , wherein said slurry drying plant is arranged for passing said superheated steam past said slurry strings substantially at atmospheric pressure.

8. A slurry drying plant according to claim 1 , wherein said plurality of exit openings are arranged at an underside of said slurry extruder so that said slurry strings are primarily extruded downwards.

9. A slurry drying plant according to claim 1 , wherein said conveyer is a screw conveyer.

10. A slurry drying plant according to claim 1 , wherein said drying plant comprises an exit pressure detector arranged to measure the pressure of said slurry at said exit openings.

11. A slurry drying plant according to claim 10 , wherein said drying plant comprises the controller configured to also control the operation of said slurry drying plant in response to input from said exit pressure detector.

12. A slurry drying plant according to claim 1 , wherein a liquid separator is arranged in said slurry extruder before said exit openings.

13. A slurry drying plant according to claim 12 , wherein said liquid separator comprises at least one sieve.

14. A slurry drying plant according to claim 1 , wherein said exit openings are formed to increase the surface area of said slurry strings.

15. A slurry drying plant according to claim 1 , wherein an inside surface of said drying chamber is provided with a non-stick surface such as polytetrafluoroethylene (PTFE), anodized aluminium, ceramics, silicone, enamelled cast iron, or stainless steel.

16. A slurry drying plant according to claim 1 , wherein said slurry extruder comprises an adjuster for adjusting the size of at least some of said exit openings.

17. A slurry drying plant according claim 16 , wherein said slurry extruder comprises the adjuster for adjusting the size of at least some of said exit openings in response to a slurry pressure inside said slurry extruder and/or said slurry inlet pressure.

18. Use of a slurry drying plant according to claim 1 for drying slurry having a solid matter content above 5%.

19. Use of a slurry drying plant according to claim 1 for drying slurry having a solid matter content above 10%.

20. Use of a slurry drying plant according to claim 1 for drying slurry having a solid matter content above 20%.

21. A method for drying slurry, said method comprising the steps of:
conveying said slurry through a slurry extruder to force said slurry out of a plurality of exit openings of said slurry extruder to form a plurality of slurry strings,
drying said slurry strings by guiding superheated steam over said slurry strings, and
controlling the speed at which said slurry is conveyed through said slurry extruder in response to a slurry inlet pressure at a slurry inlet of said slurry extruder.

22. Method according to claim 21 , wherein a binding agent is added to said slurry before said slurry is forced out of said plurality of exit openings.

23. A method according to claim 21 , wherein said slurry inlet pressure is measured by detecting a slurry level in a slurry tank arranged above said slurry extruder.

24. A method according to claim 21 , wherein said conveying speed is increased when said slurry inlet pressure increases and wherein said conveying speed is decreased when said slurry inlet pressure decreases.

25. A method according to claim 21 , wherein said method is performed by a slurry drying plant.

Assignees

• Univ Danmarks Tekniske
• Aquagreen License Aps

Inventors

• Ahrenfeldt Jesper
• Henriksen Ulrik Birk
• Thomsen Tobias Pape
• Thulstrup Claus

Classifications

• F26B21/452

  characterised by the steam generating means · CPC title

• F26B2200/18

  Sludges, e.g. sewage, waste, industrial processes, cooling towers · CPC title

• F26B23/028

  using solid fuel; burning the dried product · CPC title

• F26B17/18

  with movement performed by rotating helical blades or other rotary conveyors {which may be heated} moving materials in stationary chambers {, e.g. troughs} · CPC title

• F26B17/12

  with movement performed solely by gravity {, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft} · CPC title