Apparatus, process and pressure reactor for the treatment of solids with pressurized liquid gases

• US 6,416,621 B1
• Filed: 09/11/2000
• Issued: 07/09/2002
• Est. Priority Date: 03/13/1998
• Status: Expired due to Fees

• Current Assignee: Rhodia Acetow GmbH
• Original Assignee: Rhodia Acetow GmbH
• Inventors: Karstens, Ties
• Primary Examiner(s): Chin, Peter
• Assistant Examiner(s): HUG, JOHN ERIC
• Application Number:
  US09/646,054
• Time in Patent Office: 666 Days
• Field of Search: 162/17, 162/18, 162/19, 162/21, 162/22, 162/41, 162/46, 162/52, 162/90, 127/37, 536/30, 536/56, 422/129, 422/184.1, 422/185, 422/188, 422/189, 422/191-196, 422/232, 422/233, 422/236-239
• US Class Current: 162/22
• CPC Class Codes: B01J 19/20 in the form of helices, e.g. screw reactors
• CPC Class Codes: B01J 2219/185 vertical
• CPC Class Codes: B01J 2219/1943 cylindrical
• CPC Class Codes: B01J 3/008 Processes carried out under supercritical conditions
• CPC Class Codes: B01J 3/02 Feed or outlet devices therefor
• CPC Class Codes: C08B 1/00 Preparatory treatment of cellulose for making derivatives thereof , e.g. pre-treatment, pre-soaking, activation
• CPC Class Codes: D21C 3/024 with NH3 or H2O
• CPC Class Codes: D21C 7/00 Digesters

Abstract

The invention relates to a process for the treatment of solids with pressurized liquid gases, in particular liquid ammonia, with which the to be treated solid is fed into a pressure reactor at atmospheric pressure. Subsequently the pressurized liquid gas is fed to the pressure reactor and after a pre-set dwell time the resultant liquid gas/solid mixture is expanded explosion-like into an expansion tank. With this at least two reactors are operated in a time-staggered manner. Furthermore an apparatus is described for the treatment of solids with pressurized liquid gases, which comprises at least two parallel arranged pressure reactors for the alternating taking in of a solid and a liquid gas, which each have inlet and outlet openings for the solid provided with shut-off elements as well as each at least one inlet opening for the liquid gas, at least one expansion tank which is connected to the respective pressure reactors, and conveying means for feeding the solid as well as the liquid gas.

Claims

1. Pressure reactor for the treatment of a solid, with a pressurized gas as a liquid, a compacting device which presses together the solid filled into the pressure reactor to compact it, the reactor comprising a compacting piston which moves in a reactor chamber and compresses the solid, the compacting piston being holdable and/or lockable in a position of its maximum piston stroke.

2. Pressure reactor according to claim 1, wherein the compacting piston moves in a cylindrical reactor chamber and compresses the solid.

3. Pressure reactor according to claim 2, wherein the compacting piston has one or several ducts which extend from an underside to an upper side of the compacting piston to pass liquid.

4. Pressure reactor according to claim 1, wherein the reactor chamber comprises a compacting chamber and a reaction chamber which can be separated from one another by a shut-off device, wherein in the compacting chamber the solid is compacted and in the reaction chamber the pressurized liquid ammonia, is fed in while the shut-off device is closed.

5. Pressure reactor according to claim 4, wherein the compacting piston moves the compacted solid from the compacting chamber into the reaction chamber with the shut-off device open.

6. Pressure reactor according to claim 1, further comprising a conveying means, in particular propellant gas or compressed air, for feeding the solid into the reactor chamber and removing the solid from the reactor chamber.

7. Pressure reactor according to claim 6, further comprising a cyclone for the pressure reactor, to which on the inlet the solid can be fed in by a conveying means and which on the outlet side feeds the solid into the reactor chamber and the conveying means to a conveying means outlet.

8. Pressure reactor according to claim 1, wherein the compacting piston in the position in which it is held and/or locked, delimits a reaction area of the reactor chamber.

9. Pressure reactor according to claim 1, further comprising a sensor device to determine a filling level of the solid in the pressure reactor and/or a compacting degree or density of the solid in the pressure reactor.

10. Apparatus for the treatment of solids comprising:

at least two parallel arranged pressure reactors;

control means for operating the pressure reactors in a time-staggered manner for the alternating taking in of a solid and a liquid gas, wherein each pressure reactor has inlet and outlet openings for the solid provided with shut-off elements and at least one inlet opening for the liquid gas, wherein a said pressure reactor comprises a compacting device to press together the solid including a piston that can be locked in a position of its maximum piston stroke;

at least one expansion tank which is connected to the respective pressure reactors; and

conveying means for feeding the solid as well as the liquid gas.

11. Apparatus according to claim 10, wherein the shut-off elements of the pressure reactors are ball valves.

12. Apparatus according to claim 10, wherein the pressure reactors are vertical upright tubular cylinders.

13. Apparatus according to claim 10 wherein the conveying means for the solid comprise conveying screws.

14. Apparatus according to claim 10 wherein the conveying means for the solid comprise pneumatic conveyors.

15. Apparatus according to claim 10 further comprising means to control the feeding in of the solid and/or of the liquid gas.

16. Apparatus according to claim 10, further comprising means to cyclically control the operation of the shut-off elements of the pressure reactors.

17. Apparatus according to claim 10, wherein the pressure reactors are equipped with external heating means.

18. Apparatus according to claim 10, wherein the pressure reactors each have several inlet openings for the liquid gas.

19. Apparatus according to claim 10, wherein the pressure reactors are designed as mixers.

20. Apparatus according to claim 10, wherein the shut-off element at the inlet of each pressure reactor comprises a sluice system.

21. Apparatus according to claim 10, wherein the compacting piston moves in a cylindrical reactor chamber.

22. Apparatus according to claim 21, wherein the compacting piston has at least one duct through which liquid-passes from an underside to an upper side of the compacting piston.

23. Apparatus according to claim 10, wherein the reactor chamber comprises a compacting chamber and a reaction chamber which can be separated from one another by a shut-off device, wherein in the compacting chamber the solid is compacted and in the reaction chamber the pressurized liquid gas is fed in while the shut-off device is closed.

24. Apparatus according to claim 23 wherein the compacting piston moves the compacted solid from the compacting chamber into the reaction chamber with the shut-off device open.

25. Apparatus according to claim 21, further comprising a conveying means of propellant gas or compressed air, for feeding the solid into the reactor chamber.

26. Apparatus according to claim 25, further comprising a cyclone to which on the inlet of the pressure reactor the solid can be fed in by a conveying means and which on the outlet side feeds the solid into the reactor and the conveying means to a conveying means outlet.

27. Apparatus according to claim 10, wherein the compacting piston in the locked position delimits a reaction area of the reactor chamber.

28. Apparatus according to claim 10, further comprising a solids feeding device which feeds the solid to a pressure reactor or a group of pressure reactors, wherein the solids feeding device has a conveying propeller.

29. Apparatus according to claim 10, further comprising a preparation device for the solid, which prepares the solid before it is fed to a pressure reactor.

30. Apparatus according to claim 29, wherein the preparation device has a heating device which heats the solid.

31. Apparatus according to claim 30, wherein the heating device heats a heat carrier fluid to be fed to the solid.

32. Apparatus according to claim 31, wherein the heat carrier fluid is liquid or gaseous ammonia.

33. Apparatus according to claim 31, wherein the heating device heats the heat carrier fluid to a temperature of about 100°

C.

34. Apparatus according to claim 31, wherein the heat carrier fluid circulates in a heating circuit.

35. Apparatus according to claim 30, further comprising a conveying screw for conveying the solid, wherein the solid is heated in the conveying screw.

36. Apparatus according to claim 31, further comprising a silo for the solid, wherein the solid is heated in the silo.

37. Apparatus according to claim 10, further comprising a comminuting device for the solid.

38. Apparatus according to claim 10, further comprising a screening device for the solid.

39. Process for the treatment of solids with pressurized liquid gas comprising the steps of;

feeding the solid to be treated into a pressure reactor at atmospheric pressure;

during a reaction phase feeding pressurized liquid gas to the pressure reactor;

compacting the solid in the pressure reactor using a compacting piston that can be locked in a position of its maximum piston stroke to compress the solid;

expanding the resultant liquid gas/solid mixture into an expansion tank; and

operating at least two reactors in a time-staggered manner.

40. Process according to claim 39, further comprising the step of recovering the gas released during the expanding step.

41. Process according to claim 39, wherein the feeding of the solid into the pressure reactor is accomplished with the aid of dosing screws.

42. Process according to claim 39, wherein the feeding of the solid into the pressure reactor is by a pneumatically operating conveying device.

43. Process according to claim 39, further comprising the step of actively mixing the solid to be treated with the liquid gas in the pressure reactor.

44. Process according to claim 39, further comprising the step of opening and closing the pressure reactor by automatic control.

45. Process according to claim 39, wherein the feeding in of the solid and/or of the liquid gas is controlled automatically.

46. Process according to claim 39, further comprising dissolving or dispersing with the pressurized gas a solid or liquid additive as the gas is fed into the pressure reactor.

47. Process according to claim 46, wherein the liquid gas is mixed with the solid or liquid additive before it enters the pressure reactor.

48. Process according to claim 39, wherein said pressure reactor is charged with a solid during a filling phase, subsequently during a compacting phase the solid is compacted in the pressure reactor,

then during a reaction phase liquid gas is fed into the compacted solid in the pressure reactor, by which a liquid/solid mixture is produced, and then the liquid/solid mixture is expanded into an expansion tank.

49. Process according to claim 48, wherein before the reaction phase, the filling phase and the subsequent compacting phase of the solid in the pressure reactor are repeated until a pre-set compacting degree and/or filling level of the solid in the pressure reactor is obtained.

50. Process according to claim 48, wherein during the compacting phase a compacting stroke or several successive compacting strokes of the compacting piston are executed.

51. Process according to claim 48, wherein several pressure reactors are operated simultaneously, staggered in the aforementioned phases.

52. Process for the treatment of a solid comprising the steps:

charging a pressure reactor with solid cellulose during a filling phase,

subsequently compacting the solid cellulose in the pressure reactor,

feeding liquid pressurized ammonia gas into the compacted solid in the pressure reactor to react with the solid cellulose, by which a liquid-solid mixture is produced;

expanding the liquid/solid mixture into an expansion tank, wherein the steps are performed in several pressure reactors being operated simultaneously or staggered in several of the aforementioned steps.

53. Process according to claim 52, wherein before the steps of feeding, charging and compacting are repeated once or several times until a pre-set compacting degree and/or filling level of the solid in the pressure reactor is obtained.

54. Process according to claim 52 wherein during the compacting step a compacting stroke or several successive compacting strokes of a compacting piston of the pressure reactor are executed.