Process and apparatus for producing and using cold ammonia

• US 4,175,394 A
• Filed: 06/01/1978
• Issued: 11/27/1979
• Est. Priority Date: 06/01/1978
• Status: Expired due to Term

• Current Assignee: Laroche Industries, Inc. (Air Liquide SA)
• Original Assignee: United States Steel Corporation (U.S. Steel)
• Inventors: Wiesboeck, Robert A.
• Primary Examiner(s): Capossela, Ronald C.
• Application Number:
  US05/911,648
• Time in Patent Office: 544 Days
• Field of Search: 62/51, 111/7, 159/6 R, 55/189, 55/191
• US Class Current: 62/50.5
• CPC Class Codes: F17C 9/02 with change of state, e.g. vaporisation

Abstract

Cold ammonia, preferably cold liquid anhydrous ammonia preferably at substantially ambient or atmospheric pressure, is applied (1) to the soil as a fertilizer or (2) to feed grains, forages and anaerobically fermentable plant material to supply thereto and provide therein non-protein nitrogen (NPN). The cold ammonia is obtained by (1) introducing a stream of ambient temperature, pressurized liquid ammonia at a velocity of at least about 5000 feet per minute into an expansion chamber, the expansion chamber comprising a substantially vertically elongated barrier means located substantially in the center of the horizontal planes of the expansion chamber and, in the path of the expansion cone of the inlet stream, which barrier means assists in imparting a spinning motion to the inlet stream and allows some liquid ammonia to flow down the barrier means and thereby improves the separation of the liquid and gaseous ammonia, (2) imparting a high velocity spinning motion to the liquid ammonia entering the chamber such that rapid flow is produced around the interior of the chamber to thereby provide rapid separation of the liquid and gaseous ammonia formed in the chamber.

Claims

1. A method for carrying out the substantially adiabatic expansion of a pressurized stream of ambient-temperature liquid ammonia to produce a stream of cold liquid ammonia at a reduced pressure and a stream of cold gaseous ammonia at a reduced pressure, which comprises (1) introducing at a velocity of at least about 5000 feet per minute an inlet stream of partially decompressed liquid ammonia tangentially into an expansion chamber, the expansion chamber comprising a substantially vertically elongated barrier means located (a) substantially in the center of the horizontal planes of the expansion chamber and (b) in the path of the expansion cone of the inlet stream, which barrier means assists in imparting a spinning motion to the inlet stream and allows some liquid ammonia to flow down the barrier means and thereby improves the separation of the liquid and gaseous ammonia, (2) imparting a high velocity spinning motion to the liquid ammonia entering the chamber such that rapid flow is produced around the interior of the chamber to thereby provide rapid separation of the liquid and gaseous ammonia in the chamber, and wherein the expansion chamber is provided with an outlet useful for the removal of gaseous ammonia therefrom which outlet is located above the paths of liquid flow to minimize the amount of liquid droplets being carried through the gaseous ammonia outlet and another outlet useful for the removal of cold liquid ammonia therefrom, the outlets being provided at opposite ends of the expansion chamber, (3) directing the flow of the cold reduced pressure liquid ammonia within the expansion chamber to the outlet useful for the withdrawal of cold reduced pressure liquid ammonia from the expansion chamber to effect separation between cold liquid ammonia and cold gaseous ammonia within the expansion chamber, and (4) withdrawing through the outlet useful for the removal of gaseous ammonia a stream of cold gaseous ammonia at reduced pressure and a stream of cold liquid ammonia at reduced pressure via the other outlet.

2. Method as in claim 1 wherein the inlet stream of partially decompressed ammonia enters the expansion chamber through an inlet conduit having a cross sectional area in the plane vertical to the direction of flow of the ammonia stream of between about 0.1 and about 0.3 square inches per 1000 pounds of ammonia per hour flow rate of ammonia through the conduit and wherein the barrier means has a vertical dimension equal to at least about four times the inside diameter of the inlet conduit at the point where the inlet conduit enters the expansion chamber.

3. Method as in claim 2 wherein the barrier means is positioned so as to act as a barrier to at least the entire vertical dimension of the expansion cone of the inlet stream.

4. Method as in claim 3 wherein the barrier means has an average diameter of at least about one-fourth of the average diameter of the expansion chamber and has a vertical dimension inside the chamber of at least about two-thirds of the vertical height of the chamber, and wherein the vapor outlet is located at the top of the expansion chamber.

5. Method of claim 4 wherein the stream of ammonia entering the expansion chamber enters at a flow rate of between about 100 and about 8000 pounds per hour.

6. Method as in claim 4 wherein the barrier means is cylindrically shaped.

7. Method as in claim 6 wherein the barrier means comprises a passageway for the gaseous ammonia.

8. Method as in claim 4 wherein the barrier means comprises a cylindrically shaped tube which also serves as the outlet for the gaseous ammonia.

9. Method as in claim 8 wherein the top of the tube is near the top of the expansion chamber and wherein the gaseous ammonia is prevented from entering the tube except at or near the top of this tube and is carried downward through the tube to the bottom of the expansion chamber where it exits from the chamber.

10. Method as in claim 4 wherein the expansion chamber is in the form of a vertically elongated cylinder and wherein the liquid ammonia is introduced through an opening between about the mid-point of the vertical height and about one-fourth of the vertical height on the cylinder wall.

11. Method as in claim 10 wherein the bottom of the expansion chamber contains a barrier strip to break the spinning motion and thereby facilitate the discharge of the liquid ammonia from the expansion chamber through the outlet for the cold liquid ammonia.

12. Method of claim 2 wherein the expansion chamber has a weight of less than about 50 pounds and the volume of the expansion chamber is less than about 2 cubic feet.

13. Method as in claim 12 wherein between about 10 and about 25 percent of the pressurized liquid ammonia entering the expansion chamber is converted to gaseous ammonia which cools the balance of the liquid ammonia in the chamber so that it remains in the liquid state at substantially ambient or atmospheric pressures and wherein the volume of the expansion chamber is between about 0.03 and about 1.5 cubic feet.

14. Method as in claim 2 additionally comprising (1) directing the cold gaseous ammonia stream which leaves the expansion chamber through a mist eliminator to thereby separate liquid ammonia droplets suspended in the gaseous stream, and (2) collecting the separated liquid ammonia from the gaseous stream and combining it with the cold liquid ammonia stream from the expansion chamber.

15. Method as in claim 14 wherein the mist eliminator comprises a gauze type mist eliminator.

16. Method as in claim 15 wherein the expansion chamber is in the form of a vertically elongated cylinder and wherein the high pressure liquid ammonia is introduced through a control valve in an inlet conduit which enters an opening between about the midpoint and about one-fourth of the vertical height of the cylinder wall.

37. Apparatus as in claim 3 wherein the expansion chamber is in the form of a vertically elongated cylinder and wherein the means for introducing the partially decompressed liquid ammonia to the expansion chamber comprises a control valve in an inlet conduit and wherein this inlet conduit comprises an inlet opening between about the mid-point and about one-fourth of the vertical height of the cylinder wall.

17. A method for carrying out the substantially adiabatic expansion of a pressurized stream of ambient-temperature liquid ammonia to produce a stream of cold liquid ammonia at substantially ambient or atmospheric pressure and a stream of cold gaseous ammonia at substantially ambient or atmospheric pressure, which comprises (1) introducing a stream of ambient-temperature pressurized liquid ammonia into an inlet conduit of sufficient size to allow partial decompression of the ammonia stream to an ammonia stream velocity of at least about 5000 feet per minute and which is sufficiently expanded that upon entry into an expansion chamber that the substantially unidirectional flow of the ammonia stream is maintained, (2) introducing the ammonia stream from the inlet conduit into an expansion chamber comprising a substantially vertically elongated barrier means located substantially in the center of horizontal planes of the expansion chamber, and the barrier means extending at least the vertical dimension of the path of the expansion cone of the inlet stream at the line of intersection of the axis of the barrier means and the expansion cone, which barrier means is in the form of a hollow cylinder having a bottom impervious to entry of liquid ammonia into the cylinder and having a vertical dimension at least about two-thirds of the vertical dimension of the inside of the expansion chamber and which barrier means assists in imparting a spinning motion to the inlet ammonia stream and allows some liquid ammonia to flow down the outside of the cylinder and improves the separation of the liquid and gaseous ammonia, (3) imparting a high velocity spinning motion to the liquid ammonia entering the chamber such that rapid flow is produced around the interior of the chamber to thereby provide rapid separation of the liquid and gaseous ammonia in the chamber, and wherein the expansion chamber is provided with an outlet useful for the removal of gaseous ammonia therefrom which outlet is located above the paths of liquid flow to thereby significantly reduce the amount of liquid ammonia droplets that are carried through the gaseous ammonia outlet and another outlet useful for the removal of cold liquid ammonia therefrom, said outlets being provided at opposite ends of the expansion chamber, (4) directing the flow of the cold substantially ambient or atmospheric pressure liquid ammonia within the expansion chamber to the outlet useful for the withdrawal of cold ambient or atmospheric pressure liquid ammonia from the expansion chamber to effect separation between cold liquid ammonia and cold gaseous ammonia within the expansion chamber, and (5) withdrawing through the outlet useful for the removal of gaseous ammonia a stream of cold gaseous ammonia at substantially ambient or atmospheric pressure and a stream of cold liquid ammonia at substantially ambient or atmospheric pressure via the other outlet.

18. Method as in claim 17 wherein the inlet conduit through which the pressurized ammonia enters the expansion chamber has a cross sectional area in the plane vertical to the direction of flow of the ammonia stream of between about 0.1 and about 0.3 square inches per 1000 pounds of ammonia per hour flow rate of ammonia through said conduit.

19. Method as in claim 18 wherein the barrier means has a diameter of at least about one-fourth of the diameter of the expansion chamber.

20. Method as in claim 19 wherein the top of the hollow cylinder is near the top of the expansion chamber and wherein the gaseous ammonia is prevented from entering the cylinder except at or near the top of this cylinder and is carried downward through the cylinder to the bottom of the expansion chamber where it exits from the chamber.

21. Method as in claim 20 wherein the expansion chamber is in the form of a vertically elongated cylinder and wherein the liquid ammonia is introduced through an opening between about the mid-point of the vertical height and about one-fourth of the vertical height on the cylinder wall.

22. Method as in claim 21 additionally comprising (1) directing the cold gaseous ammonia stream which leaves the expansion chamber through a mist eliminator to thereby separate any remaining liquid ammonia droplets suspended in the gaseous stream, and (2) collecting the separated liquid ammonia from the gaseous stream and combining it with the cold liquid ammonia stream from the expansion chamber.

23. Method as in claim 22 wherein the mist eliminator comprises a gauze type mist eliminator.

24. An apparatus for carrying out the substantially adiabatic expansion of a pressurized stream of ambient-temperature liquid ammonia to produce a stream of cold liquid ammonia at a reduced pressure and a stream of cold gaseous ammonia at a reduced pressure, which comprises (1) means for introducing at a velocity of at least about 5000 feet per minute an inlet stream of partially decompressed liquid ammonia tangentially into an expansion chamber, (2) the expansion chamber comprising a substantially vertically elongated barrier means located (a) substantially in the center of the horizontal planes of the expansion chamber and (b) in the path of the expansion cone of the inlet stream, which barrier means assists in imparting a spinning motion to the inlet stream and allows some liquid ammonia to flow down the barrier means and thereby improves the separation of the liquid and gaseous ammonia, (3) means for imparting a high velocity spinning motion to the liquid ammonia entering the expansion chamber such that rapid flow is produced around the interior of the expansion chamber to thereby provide rapid separation of the liquid and gaseous ammonia in the expansion chamber, and wherein the expansion chamber is provided with (4) an outlet for removing the gaseous ammonia therefrom which outlet is located above the paths of liquid flow to minimize the amount of liquid droplets being carried through the gaseous ammonia outlet, (5) another outlet useful for the removal of cold liquid ammonia from the expansion chamber, the outlets being provided at opposite ends of the expansion chamber, (6) means for directing the flow of the cold reduced pressure liquid ammonia within said expansion chamber to the outlet useful for the withdrawal of cold reduced pressure liquid ammonia from the expansion chamber to effect separation between cold liquid ammonia and cold gaseous ammonia within the expansion chamber, (7) means for withdrawing through the outlet useful for the removal of gaseous ammonia a stream of cold gaseous ammonia at reduced pressure, and (8) means for withdrawing a stream of cold liquid ammonia at reduced pressure via the other outlet.

25. Apparatus as in claim 24 wherein the inlet stream of partially decompressed ammonia enters the expansion chamber through an inlet conduit having a cross sectional area in the plane vertical to the direction of flow of the ammonia stream of between about 0.1 and about 0.3 square inches per 1000 pounds of ammonia per hour flow rate of ammonia through said conduit and wherein the barrier means has a vertical dimension equal to at least about four times the inside diameter of the inlet conduit at the point where the inlet conduit enters the expansion chamber.

26. Apparatus as in claim 25 wherein the barrier means is positioned so as to act as a barrier to at least the entire vertical dimension of the expansion cone of the inlet stream.

27. Apparatus as in claim 26 wherein the barrier means has an average diameter of at least about one-fourth of the average diameter of the expansion chamber and has a vertical dimension inside the chamber of at least about two-thirds of the vertical height of the chamber, and wherein the vapor outlet is located at the top of the expansion chamber.

28. Apparatus as in claim 27 wherein the barrier means is cylindrically shaped.

29. Apparatus as in claim 27 wherein the barrier means comprises a cylindrically shaped tube which also serves as the outlet for the gaseous ammonia.

30. Apparatus as in claim 29 wherein the top of the tube is near the top of the expansion chamber and wherein the tube is impervious to the entrance of gaseous ammonia except at or near the top of this tube, wherein the tube for carrying the gaseous ammonia downward through the tube to the bottom of the expansion chamber where it connects with exit means for transporting the gaseous ammonia from the chamber.

31. Apparatus as in claim 27 wherein the expansion chamber is in the form of a vertically elongated cylinder and wherein means for introducing the partially decompressed liquid ammonia comprises an inlet opening between about the mid-point of the vertical height and about one-fourth of the vertical height on the cylinder wall.

32. Apparatus as in claim 31 wherein the bottom of the expansion chamber contains a barrier strip to break the spinning motion and thereby facilitate the discharge of the liquid ammonia from the expansion chamber through the outlet for the cold liquid ammonia.

33. Apparatus of claim 25 wherein the expansion chamber has a weight of less than about 50 pounds and wherein the volume of the expansion chamber is less than about 2 cubic feet.

34. Apparatus of claim 33 wherein the expansion chamber provides means for converting between about 10 and about 25 percent of the pressurized liquid ammonia entering the expansion chamber to gaseous ammonia which cools the balance of the liquid ammonia in the chamber so that it remains in the liquid state at substantially ambient or atmospheric pressures, and wherein the volume of the expansion chamber is between about 0.03 and about 1.5 cubic feet.

35. Apparatus as in claim 25 additionally comprising (1) means for directing the cold gaseous ammonia stream which leaves the expansion chamber through a mist eliminator, (2) a mist eliminator for separating liquid ammonia droplets suspended in the gaseous stream, and (3) means for collecting the separated liquid ammonia from the gaseous stream.

36. Apparatus as in claim 35 wherein the mist eliminator comprises a gauze type mist eliminator.

38. An apparatus for carrying out the substantially adiabatic expansion of a pressurized stream of ambient-temperature liquid ammonia to produce a stream of cold liquid ammonia at aub-stantially ambient or atmospheric pressure and a stream of cold gaseous ammonia at substantially ambient or atmospheric pressure, which comprises (1) means for introducing a stream of ambient-temperature pressurized liquid ammonia into an inlet conduit at an ammonia stream velocity of at least about 5000 feet per minute, (2) the inlet conduit of sufficient size to allow partial decompression of the ammonia stream in order that the ammonia stream is sufficiently expanded that upon entry into an expansion chamber that the substantially unidirectional flow of the ammonia stream is maintained, (3) the expansion chamber comprising a substantially vertically elongated barrier means, (4) the barrier means being located substantially in the center of horizontal planes of the expansion chamber, and the barrier means extending at least the vertical dimension of the path of the expansion cone of the inlet stream at the line of intersection of the axis of the barrier means and the expansion cone, which barrier means is in the form of a hollow cylinder having a bottom inpervious to entry of liquid ammonia into the cylinder and having a vertical dimension at least about two-thirds of the vertical dimension of the inside of the expansion chamber and which barrier means assists in imparting a spinning motion to the inlet ammonia stream and allows some liquid ammonia to flow down the outside of the cylinder and improves the separation of the liquid and gaseous ammonia, (5) means for imparting a high velocity spinning motion to the liquid ammonia entering the chamber such that rapid flow is produced around the interior of the chamber to thereby provide rapid separation of the liquid and gaseous ammonia in the chamber, and wherein the expansion chamber is provided with (6) an outlet useful for the removal of gaseous ammonia therefrom which outlet is located above the paths of liquid flow to thereby significantly reduce the amount of liquid ammonia droplets that are carried through the gaseous ammonia outlet, and (7) another outlet useful for the removal of cold liquid ammonia therefrom, said outlets being provided at opposite ends of said expansion chamber, (8) means for directing the flow of the cold substantially ambient or atmospheric pressure liquid ammonia from the expansion chamber to effect separation between cold liquid ammonia and cold gaseous ammonia within the expansion chamber, (9) means for withdrawing through the outlet useful for the removal of gaseous ammonia a stream of cold gaseous ammonia at substantially ambient or atmospheric pressure, and (10) means for withdrawing a stream of cold liquid ammonia at substantially ambient or atmospheric pressure via the other outlet.

39. Apparatus as in claim 38 wherein the inlet conduit through which the pressurized ammonia enters the expansion chamber has a cross sectional area in the plane vertical to the direction of flow of the ammonia stream of between about 0.1 and about 0.3 square inches per 1000 pounds of ammonia per hour flow rate of ammonia through said conduit.

40. Apparatus as in claim 39 wherein the barrier means has a diameter of at least about one-fourth of the diameter of the expansion chamber.

41. Apparatus as in claim 40 wherein the top of the hollow cylinder is near the top of the expansion chamber and wherein the gaseous ammonia is prevented from entering the cylinder except at or near the top of this cylinder and is carried downward through the cylinder to the bottom of the expansion chamber where it exits from the chamber.

42. Apparatus as in claim 41 wherein the expansion chamber is in the form of a vertically elongated cylinder and wherein the liquid ammonia is introduced through an opening between about the mid-point of the vertical height and about one-fourth of the vertical height on the cylinder wall.