Back to results
US 11,331,593 B2Granted
Urea plant with stripper and stripping method
AssigneeStamicarbon B.V.
InventorsLambertus Wilhelmus Gevers, Juan Coloma González
Life of this patent
Estimating the term…
Abstract
A method is disclosed for stripping in a stripper a urea synthesis solution received from a urea forming process wherein ammonia and CO2 are reacted under urea forming conditions. The shell space of the stripper comprises a continuous vertical zone.
Claims20
A method for stripping a urea synthesis solution received from a urea forming process wherein ammonia and CO2 are reacted under urea forming conditions, wherein the urea synthesis solution comprises urea, water and ammonium carbamate, the method comprising:
- subjecting the urea synthesis solution to stripping and indirect heat exchange with a gaseous heating fluid in a stripper, wherein the stripper is a vertical shell-and-tube heat exchanger comprising a tube bundle comprising tubes, a shell and a shell space, wherein the urea synthesis solution is provided as falling film in the tubes and wherein the heating fluid is supplied in the shell space and condenses at least in part in the shell space,
- wherein the tube bundle has an effective tube length of 4 to 9 m, wherein each tube of said tubes comprises a tube part that is in contact with the heating fluid, wherein the effective tube length is the length of said tube part that is in contact with the heating fluid,
- wherein the tube bundle has an outer tube limit and a ratio of the effective tube length to the outer tube limit diameter that is 2.5 or less, wherein the outer tube limit is the diameter of the circle created by encircling the outermost tubes in the tube bundle,
- wherein the shell space has, at each vertical level where the tubes are contacted with heating fluid, a drainage area for heating fluid condensate, the drainage area being the empty area of the shell space suitable for drainage of condensate present on the shell side of the tubes,
- wherein said shell space comprises a continuous vertical zone of at least 1.6 m vertical length, wherein:
- (i) in said continuous vertical zone for each horizontal cross section along the plane perpendicular to the tubes of said shell space, the difference in drainage area between any two circular areas of at least 0.25 m2 which have the same size and which are located in a region in said horizontal cross section and within said outer tube limit is less than 5% relative to the average drainage area of the two circular areas, and/or
- (ii) wherein said continuous vertical zone does not include baffles.
4 more elements
A urea plant comprising a high pressure synthesis section comprising a urea reaction section, a high pressure carbamate condenser and a stripper,
- wherein the stripper is configured as vertical falling film shell-and-tube heat exchanger and comprises a tube bundle comprising tubes, a shell, and an upper tube sheet and a lower tube sheet, and a shell space provided in the shell between the upper tube sheet and the lower tube sheet,
- wherein the stripper is adapted for maintaining a falling film of urea synthesis solution to be stripped in the tubes and comprises an inlet for gaseous heating fluid supplied to the shell space and an outlet for gaseous heating fluid and heating fluid condensate from the shell space,
- wherein the tube bundle has an effective tube length of 4 to 9 m, wherein each tube of said tubes comprises a tube part that is in contact with the heating fluid, wherein the effective tube length is the length of said tube part that is in operation of the plant in contact with the heating fluid,
- wherein the tube bundle has an outer tube limit and a ratio of the effective tube length to the outer tube limit diameter that is 2.5 or less, wherein the outer tube limit is diameter of the circle created by encircling the outermost tubes in the tube bundle,
- wherein the shell space has, at each vertical level where the tubes are contacted with the heating fluid, a drainage area for heating fluid condensate, the drainage area being the empty area of the shell space suitable for drainage of condensate present on the shell side of the tubes,
- wherein said shell space comprises a continuous vertical zone of at least 1.6 m vertical length wherein (i) in said continuous vertical zone for each horizontal cross section along the plane perpendicular to the tubes of said shell space in said vertical zone, the difference in drainage area between any two circular areas of at least 0.25 m2 which have the same size and which are located in said horizontal cross section within said outer tube limit is less than 5% relative to the average drainage area of the two circular areas and/or (ii) wherein said continuous vertical zone does not include baffles.
3 more elements
A method for stripping a urea synthesis solution received from a urea forming process wherein ammonia and CO2 are reacted under urea forming conditions, wherein the urea synthesis solution comprises urea, water and ammonium carbamate, the method comprising:
- subjecting the urea synthesis solution to stripping and indirect heat exchange with a gaseous heating fluid in a stripper, wherein the stripper is a vertical shell-and-tube heat exchanger comprising a tube bundle comprising tubes, a shell and a shell space, wherein the urea synthesis solution is provided as falling film in the tubes and wherein the heating fluid is supplied in the shell space and condenses at least in part in the shell space,
- wherein the tube bundle has an effective tube length of 4 to 9 m, wherein each tube of said tubes comprises a tube part that is in contact with the heating fluid, wherein the effective tube length is the length of said tube part that is in contact with the heating fluid, wherein tubes are supported by strips having a width of less than 10 mm.
A high pressure stripper for a urea plant comprising a vertical shell-and-tube heat exchanger comprising a tube bundle comprising tubes, a shell, and an upper tube sheet and lower tube sheet, and a shell space provided in the shell between the upper and lower tube sheet,
- wherein the stripper is adapted for maintaining a falling film of urea synthesis solution to be stripped in the tubes and comprises an inlet for gaseous heating fluid supplied to the shell space and an outlet for gaseous heating fluid and heating fluid condensate from the shell space,
- wherein the inlet for heating fluid is arranged higher than the outlet for condensate from the shell space, wherein the tubes of the tube bundle are supported by strips having a width of less than 10 mm.
A high pressure stripper for a urea plant comprising a vertical falling film shell-and-tube heat exchanger which comprises a tube bundle comprising tubes, a shell, and an upper tube sheet and a lower tube sheet, and a shell space provided in the shell between the upper tube sheet and the lower tube sheet,
- wherein the stripper is adapted for maintaining a falling film of urea synthesis solution to be stripped in the tubes and comprises an inlet for gaseous heating fluid supplied to the shell space and an outlet for gaseous heating fluid and heating fluid condensate from the shell space,
- wherein the tube bundle has an effective tube length of 4 to 9 m, wherein each tube of said tubes comprises a tube part that is in contact with the heating fluid, wherein the effective tube length is the length of said tube part that is in operation of the plant in contact with the heating fluid,
- wherein the tube bundle has an outer tube limit and a ratio of the effective tube length to the outer tube limit diameter that is 2.5 or less, wherein the outer tube limit is diameter of the circle created by encircling the outermost tubes in the tube bundle,
- wherein the shell space has, at each vertical level where the tubes are contacted with the heating fluid, a drainage area for heating fluid condensate, the drainage area being the empty area of the shell space suitable for drainage of condensate present on the shell side of the tubes, wherein said shell space comprises a continuous vertical zone of at least 1.6 m vertical length wherein (i) in said continuous vertical zone for each horizontal cross section along the plane perpendicular to the tubes of said shell space in said vertical zone, the difference in drainage area between any two circular areas of at least 0.25 m2 which have the same size and which are located in said horizontal cross section within said outer tube limit is less than 5% relative to the average drainage area of the two circular areas and/or (ii) wherein said continuous vertical zone does not include baffles.
1 more element
A urea plant comprising a high pressure synthesis section comprising a urea reaction section, a high pressure carbamate condenser and a stripper,
- wherein the stripper is configured as vertical falling film shell-and-tube heat exchanger and comprises a tube bundle comprising tubes, a shell, and an upper tube sheet and a lower tube sheet, and a shell space provided in the shell between the upper tube sheet and the lower tube sheet,
- wherein the stripper is adapted for maintaining a falling film of urea synthesis solution to be stripped in the tubes and comprises an inlet for gaseous heating fluid supplied to the shell space and an outlet for gaseous heating fluid and heating fluid condensate from the shell space,
- wherein the tube bundle has an effective tube length of 4 to 9 m, wherein each tube of said tubes comprises a tube part that is in contact with the heating fluid, wherein the effective tube length is the length of tube part that is in operation of the plant in contact with the heating fluid,
- wherein the tube bundle has an outer tube limit and a ratio of the effective tube length to the outer tube limit diameter that is 2.5 or less, wherein the outer tube limit is diameter of the circle created by encircling the outermost tubes in the tube bundle,
- wherein the tubes are supported by strips having a width of less than 10 mm.
2 more elements
Dependencies are inferred from the claim text.