IPE-TM-300 Vessels
Fractionator Internals Mechanical Design Summary
IPE-TM-300-08
Table of Contents
1. Table of Contents 1
2. Purpose 1
3. General 1
4. Accumulator Trays (Form F-PSD-18) 2
4.1 Partial Drawoff Accumulator Trays 2
4.2 Total Drawoff Accumulator Trays 5
5. Collector Trays (Form F-PSD-16) 6
6. Blind Trays (Form F-PSD-16) 7
7. Reboiler Drawoff Wells (Form F-PSD-16) 8
8. Stabbed-In Reboiler Tubs (Form F-PSD-16) 8
8.1 Stabbed-In Reboiler Tub Between Trays 8
8.2 Stabbed-in Reboiler Tub Below Bottom Tray 9
9. Drawoff Sumps (Forms F-PSD-18 and F-PSD-21) 9
10. Traps 10
10.1 Regular Traps (Form F-PSD-21) 10
10.2 Baffled Traps (Form F-PSD-21) 11
10.3 Distributor Traps (Form F-PSD-17) 11
11. Baffle Trays (Form F-PSD-19) 12
11.1 Side to Side Pans 12
11.2 Disc and Donut Pans 12
12. Summary Forms 13
13. References 14
14. Metric Dimensions 14
15. Example 14
Example Calculations 15
Accumulator Trays (Form F-PSD-18) 15
Attachment 1 Index Example 18
Attachment 2 Loading Specifications Example 20
Layouts and details for sieve, valve and bubble cap trays and packing distributors, retainers and supports are not covered in these guidelines.
2. Purpose
This procedure provides guidelines for determining the dimensions and requirements used in the design of the internals indicated on the Project Specification 301 vessel sketch, which are not covered in the Fractionator Summary Sheet of the Process Specification.
3. General
Use this information, in addition to the Fractionator Summary Sheet and Project Specification 301, Vessels, for the preparation of Project Specification 307, Trays and Packing, and the review of vendor's drawings related to the internals.
4. Accumulator Trays (Form F-PSD-18)
Accumulator trays (partial & total) are sized and arranged according to the diagram shown below. While P254 contains a number of algorithms to determine the dimensions of each segment, only the algorithm that typically governs is discussed in this document to ensure clarity. The designer should consult with the vessels specialist to discuss the impact of other algorithms upon the dimensions.
4.1 Partial Drawoff Accumulator Trays
These trays accumulate liquid descending from above to provide a capacitance for the liquid withdrawal from the fractionator. At the same time, these trays allow some of the liquid to continue flowing down the vessel by means of overflow weirs and downcomers and allow all the rising vapor to continue flowing up the vessel through vapor risers. See Form F-PSD-18; Standard Drawings 3-290, 3-292, 3-294, 3-296, 3-298; 3-396 (for skim baffle) applications and the following dimensional relationships.
a. Tray Above to Top of Vapor Riser
The distance from the tray above to the top of the chimney is set equal to the tray spacing of the trays above the accumulator. This dimension is limited to a minimum value of 18” (regardless of tray spacing) to ensure there is adequate space for the chimney hat & vapor distribution to the tray above.
b. Top of Vapor Riser to Floor of Seal Pan (trap)
The distance from the top of the chimney to the floor of the trap is set to 6”. This ensures that liquid from the downcomers above will not pour into the vapor risers. Designers may deviate from this dimension on the recommendation of the Technology Specialist.
c. Floor of Seal Pan (trap) to Top of Overflow Weir
The distance from the floor of the trap to the top of the overflow weir is set to 6”. Designers may deviate from this dimension on the recommendation of the Technology Specialist.
d. Top of Overflow Weir to Bottom of Accumulator
The distance from the top of the overflow weir to the bottom of the accumulator is dependent upon the residence time to be accumulated on the tray. This volume is determined by the residence time (normally two minutes) and the liquid withdrawal rate. The height required for the liquid volume (LV) is dependent upon the cross-sectional areas of the overflow downcomers and the vapor risers, which are assumed to be a total of 25 percent of the vessel cross-sectional area. The height of the overflow weir 13 is at least equal to the TS:
LV (inches) = 2.7 x residence time (minutes) x liquid withdrawal rate (gpm)
(Vessel I.D., ft) 2
P254 calculates , and then checks this dimension against the other sizing algorithms. The actual overflow weir height may be larger than that required to satisfy This indicates that another sizing algorithm governed this dimension. The height of the overflow weir is set 6 inches below the floor level of the seal pan(s) (trap) for the downcomer(s) of the tray above. When the service utilizes a skim baffle (such as a sour water stripper), the top of the skim baffle is set 2 1/2 inches (65) below the floor level of the seal pan(s) (trap) for the downcomers of the tray above (see Standard Drawing 3-396).
e. The length of the downcomer to the tray below the accumulator tray (which is the downward extension of the overflow weir), is dependent upon the required spacing between the accumulator tray and the tray below, and the downcomer clearance that has been determined for the trays immediately below. P254 calculates these dimensions and enters them onto the vessel drawing. The downcomer arrangement of trays below the total drawoff accumulator is independent of the accumulator and the tray above.
f. The width of the downcomers through are set the same as the equivalent downcomer(s) of the trays below, which may be the same or a lesser number of passes than the tray above. Intermediate and center downcomers should not be continuous across the tray to avoid restricting liquid flow to the drawoff nozzle.
g. The total cross-sectional area of the vapor risers is set to at least 12 percent of the vessel cross-sectional area of the trayed section above the accumulator tray for non-vacuum service (20 percent for vacuum service). The vapor riser cross-sectional area shall be proportioned in accordance with the downcomer arrangement of the tray above as follows (see Form F-PSD-18):
riser area or = total riser area
riser area , or = 0.5 x total riser area
riser area = 0.67 x total riser area
riser area = 0.33 x total riser area
riser area = 0 .25 x total riser area
Vapor risers shall not be continuous across the tray to avoid restricting liquid flow to the drawoff nozzle.
Mechanically, there may be several vapor risers in each of the areas above. However, set the total area for each grouping of risers as indicated above.
h. The clearance between the top of the riser and the baffle (hat) above the riser is based on the number, size and shape of the risers and baffles as designed by the tray supplier, and the requirement that the reversal area for vapor flow between the top of the riser and the baffle is at least 1.25 times the cross-sectional area of the riser. The baffle is expected to be designed with an upturned lip to direct liquid falling from above to an area where there is no vapor flow to prevent the liquid from being entrained in the vapor.
i. The details of the drawoff sump for the drawoff nozzle are discussed in Section 9. The depth of the sump is set to a minimum of 1.5 times the liquid withdrawal nozzle diameter.
j. The joints in the tray floor, and downcomer(s) and vapor riser(s) above the floor level must be seal welded to prevent excessive leakage. Tray manways must be gasketed. See Inflection Point Engineering Standard Specification 3-18, II, E.
4.2 Total Drawoff Accumulator Trays
Total drawoff trays accumulate all of the liquid descending from above to provide a surge volume of liquid for withdrawal from the fractionator. At the same time, these trays allow all the rising vapor to continue flowing up the vessel through vapor risers. This type of accumulator tray is sized the same as the partial drawoff accumulator tray except the total drawoff tray has no downcomers. See Form F-PSD-18, Standard Drawing 3-288 and the following dimensional relationships.
a. The distance between the tray above to the top of the riser are as discussed in Section 4.1.a.
b. The distance between the top of the riser to the floor of seal pan (trap) are as discussed in Section 4.1.b.
c. The distance between the floor of seal pan (trap) to the top of the overflow weir are as discussed in Section 4.1.c.
d. Top of Overflow Weir to Bottom of Accumulator
The surge height (TS) is determined by the surge time (normally two minutes) and the withdrawal rate, and the cross-sectional area of the vapor risers which is assumed to be a total of 12 percent of the vessel cross-sectional area (20 percent for vacuum service).
TS (inches) = 2.3 x surge time (minutes) x withdrawal rate (gpm)
(Vessel I.D., ft)2
Round the calulcated TS to the next larger standard range of a top-side level transmitter. See Procedure IPE-TM-300-02. The bottom level nozzle is 3 inches above the floor of the accumulator tray. Use this rounded TS in determining the minimum vapor riser height. See Section 4.2.c.
e. The length of the downcomer to the tray below the accumulator tray are as discussed in Section 4.1.e.
f. The width of the downcomers are as discussed in Section 4.1.f.
g. The cross-sectional area of the vapor risers are as discussed in Section 4.1.g.
h. The clearance between the top of the risers and the baffle (hat) are as discussed in Section 4.1.h.
i. The details of the drawoff sump for the drawoff nozzle are discussed in Section 9. The depth of the sump is set to a minimum of 1.5 times the liquid withdrawal nozzle diameter.
j. The joints in the tray floor, and downcomer(s) and vapor riser(s) above the floor level must be seal welded to prevent excessive leakage. Tray manways must be gasketed. See Inflection Point Engineering Standard Specification 3-18, II, E.
5. Collector Trays (Form F-PSD-16)
These trays collect all the liquid descending from above and direct the liquid through a downcomer, while allowing all of the rising vapor to continue flowing up the vessel through vapor risers. The collector tray prevents any liquid weeping from the bottom tray from by-passing the types of reboilers in Sections 5.1.a, b and c. See Form F-PSD-16 and Standard Drawings 3-340, 3-341, 3-342, 3-344, 3-345, 3-346, 3-348, 3-350 and 3-352.
5.1 Base the downcomer chord height upon the type of reboiler: (Downcomer chord heights may be calculated by using circle segmental function charts.)
a. If the liquid is to be routed to a stabbed-in reboiler, see Section 8, “Stabbed-In Reboiler Tubs (Form F-PSD-16) to determine the downcomer chord height.
b. If the liquid is to be routed to a preferential once-through reboiler, base the chord height on a liquid velocity of no greater than 0.2 ft/s.
c. If the liquid is to be routed to an absolute once-through reboiler, base the chord height on a liquid velocity of no greater than 0.2 ft/s because the downcomer and drawoff well are one piece.
5.2 The length of the downcomer is dependent upon the type of reboiler:
a. If the liquid is to be routed to a stabbed-in reboiler, the downcomer extends to 6 inches above the floor of the reboiler tub to allow uniform flow across the bottom of the reboiler. See Form F-PSD-16.
b. If the liquid is to be routed to a preferential once-through reboiler, the downcomer extends 1.5 feet below the top of the drawoff well to direct the liquid to the drawoff nozzle. See Form ”.
c. If the liquid is to be routed to an absolute once-through reboiler, the downcomer is continuous from the floor of the collector tray to the invert of the reboiler drawoff nozzle. This downcomer is the drawoff well to the reboiler and is normally furnished by the vessel fabricator because it is welded directly to the vessel shell. See Form F-PSD-16.
5.3 Orient the downcomer 90 degrees from the downcomer(s) of the tray above to ensure adequate area for liquid entrance into the downcomer and adequate area for the vapor risers.
5.4 The cross-sectional area of the vapor risers is as discussed in Section 4.1.d.
5.5 Set the height of the vapor risers 6 inches above the floor level of the seal pan (trap) for the downcomer of the tray above. In most cases this will be 1.5 feet above the collector tray floor.
5.6 The clearance between the top of the riser and the baffle (hat) and the details of the baffle are as discussed in Section 4.1.f.
5.7 Seal weld the joints in the tray floor and vapor riser(s) to prevent excessive leakage. Tray manways are to be gasketed. Seal weld the joints in the downcomer of Section 5.2.c.
6. Blind Trays (Form F-PSD-16)
These trays direct all liquid descending from above through a downcomer to downstream processing, without allowing any vapor flow through the tray. See Form F-PSD-16 and Standard Drawings 3-282 and 3-284. Blind trays have short length baffles at the top of the downcomer and adjacent to the vessel shell to allow any vapor trapped below the tray to escape through the downcomer.
6.1 Base the downcomer width or on a liquid velocity in the downcomer of no greater than 0.2 ft/s.
6.2 The downcomer extends 3 inches below the floor level of the blind tray.
6.3 The baffles for vapor escape are 6 inches high and 6 inches long and are located at the top of the downcomer and attached to the vessel at each end of the downcomer.
6.4 Seal weld the joints in the tray floor to prevent excessive leakage. Tray manways are to be gasketed.
7. Reboiler Drawoff Wells (Form F-PSD-16)
These drawoff wells provide surge for preferential once-through, absolute once-through and vertical thermosiphon reboilers. See Form F-PSD-16 and Inflection Point Engineering Standard Drawing 3-274.
7.1 Set the drawoff well chord height for absolute once-through, for preferential once-through and for vertical thermosiphon reboilers to allow a liquid velocity of no greater than 0.2 ft/s, be at least 3 inches larger for and than the chord height of the downcomer(s) feeding it, and provide a surge time of not less than 0.5 minutes for thermosiphon and 1.0 minute for fired reboilers. (Downcomer chord heights may be calculated by using circle segmental function charts.)
7.2 The height of the drawoff well is expected to be as dimensioned on the vessel sketch in Project Specification 301 or as indicated on Form F-PSD-16.
7.3 Seal weld the joints of the drawoff well to prevent excessive leakage.
7.4 Provide an inspection/clean-out opening near the bottom of the drawoff well. The cover plate for the opening is to be bolted and gasketed. See Inflection Point Engineering Standard Drawing 3-274.
8. Stabbed-In Reboiler Tubs (Form F-PSD-16)
8.1 Stabbed-In Reboiler Tub Between Trays
This tub receives the descending liquid from the collector tray above, provides a reservoir for boiling the liquid and directs the net liquid to the tray below. See Form F-PSD-16 and Standard Drawing 3-273.
a. Make the overflow weir of the tub parallel to the reboiler bundle and to the downcomer of the collector tray.
b. Set the height of the overflow weir 2 inches above the top of the reboiler nozzle.
c. Make the clearance between the side of the tub and the reboiler nozzle 2 inches to minimize the bypassing of liquid around the reboiler. Check chord height 9 to ensure the liquid velocity is no greater than 0.2 ft/s. Consult the vessel/tray specialist if the velocity exceeds 0.2 ft/s.
d. Locate the floor of the tub 6 inches below the bottom of the reboiler nozzle.
e. Size the width of the overflow downcomer for the net liquid from the tub for a velocity of 0.3 ft/s or less.
f. Extend the top of the downcomer 6 inches above the top of the overflow weir of the tub.
g. Size the clearance between the bottom of the overflow downcomer and the trap below for a liquid velocity of 2 ft/s or less, but not be less than 1.5 inches.
h. Design the outlet weir of the trap like a distributor trap. See Section 10.3.
i. The reboiler tub is furnished as part of the vessel by the vessel fabricator and is specified to be liquid tight by seal welding and to be adequately stiffened to support the reboiler bundle and the liquid load.
8.2 Stabbed-in Reboiler Tub Below Bottom Tray
This tub receives the descending liquid from the collector tray above, provides a reservoir for boiling the liquid and directs the net liquid to the bottom of the vessel. See Form F-PSD-16, Standard Drawings 3-270 and 3-272 and Sections 8.1.a through 8.1.d and 8.1.i.
9. Drawoff Sumps (Forms F-PSD-18 and F-PSD-21)
The sump is a depressed volume below the tray floor to provide an adequate liquid head to compensate for the pressure drop through the drawoff nozzle. See Forms F-PSD-18 and F-PSD-21.
9.1 Make the depth or of the sump 1.5 times the diameter of the drawoff nozzle. When the drawoff nozzle and sump are located under a center or intermediate downcomer and the vessel diameter is larger than 12 feet, the drawoff sump extends the full depth across the vessel with a drawoff nozzle at both ends of the sump. Size the drawoff nozzle(s) for pump suction conditions.
9.2 Set the width of the sump equal to the diameter of the drawoff nozzle and widths and equal to the width of the downcomer above.
9.3 Make the length of the sump 3 inches larger than the diameter of the drawoff nozzle or full chord length, whichever is appropriate.
9.4 Locate the top of the floor of the sump flush with the invert of the drawoff nozzle.
9.5 Seal weld the sump to be liquid tight.
9.6 Check to ensure that the space under the total accumulator having 2 liquid draws is large enough to accommodate the sump & return nozzles.
The spacing dimension below the accumulator tray should be calculated according to the following algorithm:
Accumulator spacing= 1.5Dout+0.6(Normal Tray Spacing)+DInlet+3”
Use the larger of the hand calculated dimension or the dimension provided by P254.
10. Traps
10.1 Regular Traps (Form F-PSD-21)
These traps provide a liquid static seal at the bottom of the downcomer that is not sealed on the tray below, to prevent vapor from rising up the downcomer and prematurely flooding the downcomer. Use regular traps only under chordal downcomers. See Form F-PSD-21 and Standard Drawing 3-280.
a. Set the height of the overflow weir 4 inches to provide a static seal for protection from incoming streams and pressure surges. Orient inlet nozzles and distributors so that they do not impinge on the overflow weir of the trap.
b. Make the horizontal clearance between the downcomer and the weir 4 inches to minimize the velocity and pressure drop of the liquid exiting the downcomer.
c. Make the distance of the trap below the tray above, normal tray spacing of the trays above, plus 6 inches. This will accommodate the additional liquid backup in the downcomer resulting from the 4 inch weir height of the trap.
d. Locate a drain hole, preferably 0.5-inch round or square, at the bottom of the weir or in the trap floor outside of the downcomer area.
10.2 Baffled Traps (Form F-PSD-21)
These traps, in addition to providing a liquid static seal, provide for vapor flow under the trap by intermittent baffles above the weir, which interrupt the continuous curtain of liquid overflowing the weir. This allows for vapor equalization across the vessel. Use baffled traps only under center or intermediate downcomers. See Form F-PSD-21, Standard Drawing 3-280 and Sections 10.1.a through 10.1.d.
a. In general, the baffles extend 4 inches above the top of the weir, are 15 inches long and are spaced on 63 inch centers.
10.3 Distributor Traps (Form F-PSD-17)
These traps, in addition to providing a liquid static seal, provide for liquid distribution to the tray below. See Form F-PSD-17, Standard Drawings 3-192 to 3-250 and 3-400 to 3-417 and Sections, 10.1.c and 10.1.d.
a. Make the horizontal clearance between the downcomer and the weir 6 inches to provide adequate area for liquid flow to the overflow weir at the bottom of the notch.
b. Type A trap to feed a 1 pass tray has an overflow weir length equal to 0.6 of the chord height of the tray below.
c. Type B trap to feed a 2 pass side downcomer tray has an overflow weir length equal to the width of the center downcomer of the second tray below plus 4 inches.
d. Type C trap to feed a 2 pass center downcomer tray has overflow weir lengths equal to 0.6 of the chord height of the side downcomers of the second tray below.
e. Type D trap to feed a 3 pass tray has an overflow weir length equal to the width of the intermediate downcomer of the tray below plus 4 inches and an overflow weir length equal to 0.5 of .
f. Type E trap to feed a 4 pass intermediate downcomer tray has an overflow weir length equal to the width of the center downcomer of the second tray below plus 4 inches and overflow weir lengths equal to 0.5 of .
g. Type F trap to feed a 4 pass side-center downcomer tray has overflow weir lengths equal to the width of the intermediate downcomers of the second tray below plus 4 inches.
h. Set the height of the overflow weir from the trap floor equal to the height of the overflow weir of the tray above with a minimum of 1.5 inches. Use 2 inches for valve trays.
i. Make the height of the baffle above the overflow weir at least 4 inches, but check this dimension to make sure that it is at least 0.5 inches greater than the liquid head over the weir. Use the following equation to calculate the head over the weir:
| how = 0.4 | how = head over weir, inches gpm = gallons per minute of flow from downcomer(s) wl = total weir length of notched sections, inches |
|---|
11. Baffle Trays (Form F-PSD-19)
These trays provide a mechanism for liquid/vapor contacting by passing the ascending vapor through streams and curtains of descending liquid. Baffle trays are usually designed to maximize the dispersion of liquid and optimize the contacting of liquid and vapor with high capacities. The capacity of a baffle tray increases by increasing the area available for vapor flow. The most common types of baffle trays are side to side pans and disc and donut pans. See Form F-PSD-19 and Standard Drawings 3-252, 3-254, 3-256, 3-258, 3-260 and 3-262.
11.1 Side to Side Pans
Design these pans as non-overlapping or overlapping depending upon the process requirements. See Types A and B on Form F-PSD-19. Expanded metal lath may be placed under the perforated overlapping section of the pan to increase the dispersion of the liquid. See Type C on Form F-PSD-19. Typical vapor flow areas and hole diameters and pitches are shown on Form F-PSD-19 for Types A, B and C. Specify chordal weirs only for pans on which liquid feed is introduced.
11.2 Disc and Donut Pans
Design these pans as non-overlapping or overlapping depending upon the process requirements. See Types D and E on Form F-PSD-19. Typical flow areas and hole diameters and pitches are shown on Form F-PSD-19 for Types D and E.
Specify circular weirs on donut pans located directly below a tray with downcomers. The weir provides a liquid static seal for the downcomer. At other liquid inlet points, introduce the liquid at the center of a disc pan which has a center blank circular area equal to 0.5 times the area of the pan. If the feed stream contains abrasives, place a circular wear plate over the blank center area.
12. Summary Forms
The following forms contain the basis for determining and the space for recording the necessary information for the subject internals. Access these forms on the Intranet .
| Form No. | Title |
|---|---|
| ” | |
13. References
Consult the following Documentation System Procedures, Inflection Point Engineering Standard Specification and Standard Drawings for additional information.
| Document No. | Title |
|---|---|
| Procedure IPE-TM-300-01 | Metric Equivalents for Vessels and Trays |
| Procedure IPE-TM-300-02 | Vessel Level Instrument and Level Indicator Installation |
| Procedure IPE-TM-300-03 | Vessel Nozzles, Internals and Ancillaries |
| Procedure PSD-18 | Project Specification 301 Preparation |
| Standard Specification 3-18 | Trays and Packing (Random and Structured) |
| Standard Drawings 3-192 to 250, 3-400 to 417 | Distributor Traps |
| Standard Drawings 3-270 to 273 | Stabbed in Reboiler Tubes |
| Standard Drawing 3-274 | Drawoff Wells for Reboilers |
| Standard Drawings 3-290 to 298 | Partial Drawoff Accumulator Trays |
| Standard Drawing 3-288 | Total Drawoff Accumulator Trays |
| Standard Drawings 3-340 to 352 | Collector Trays |
| Standard Drawings 3-282, 284 | Blind Trays |
| Standard Drawing 3-280 | Traps |
| Standard Drawing 3-252 | Disc and Donut Pans |
| Standard Drawings 3-254 to 262 | Side to Side Pan |
14. Metric Dimensions
This procedure assumes that the required values are determined by using English units. When the required values are to be in metric units, convert the English units to metric using the guidelines in Procedure TEC-300-01, “Metric Equivalents for Vessels and Trays”.
15. Example
The example as indicated below includes the vessel sketch showing the arrangement of the internals, the calculations necessary for the design of the internals, the completed summary forms recording the calculated information, and the section of Project Specification 307 with the requirements for the internals of the vessel.
Page No.
Calculations 13 - 15
Vessel Sketch Attachment
Summary Forms Attachment
Project Specification 307 Attachment
Example Calculations
Accumulator Trays (Form F-PSD-18)
Vapor Riser Areas
Below Tray No. 6 ( = 7600 mm = 24.9 ft)
Column Cross - Sect. Area = 3.14(24.9)2 = 486.7 ft2
4
Riser Cross - Sect. Area = 0.06 (486.7) = 29.2 ft2
= 2.72 m2
Below Tray No. 20 ( = 7600 mm = 24.9 ft)
Same as for Below Tray No. 6
Below Tray No. 28 ( = 7600 mm = 24.9 ft)
Same as for Below Tray No. 20
Below Tray No. 6
Liquid Withdrawal Rate = 4046 gpm (H&W Balance)
Surge Time = 2.0 minutes
Total Surge (TS) = 2.7 (2.0) 4046 = 35.2 in
(24.9)2 = 894 mm
(This is the minimum height)
(Set weir height at 1300 mm based on the elevation of the seal pans for Tray No. 6; 2200 - 750 - 150 = 1300 mm).
Below Tray No. 20
Liquid Withdrawal Rate = 1680 gpm (H&W Balance)
Surge Time = 2.0 minutes
Total Surge (TS) = 2.7 (2.0) 1680 = 14.6 in
(24.9)2 = 371 mm
(This is the minimum height)
(Set weir height at 650 mm based on the elevation of the seal pans for Tray No. 20; 1700 - 900 - 150 = 650 mm).
Drawoff Wells
Below Tray No. 6
Drawoff Nozzle Diameter = 16 in
= 1.5 (16) = 24 in
= 610 mm
= 16 in
= 406 mm, round to 410 mm
= 16 + 3 = 19 in
= 483 mm, round to 480
Below Tray No. 20
Drawoff Nozzle Diameter = 14 in
= 1.5 (14) = 21 in
= 533 mm, round to 530 mm
= 14 in
= 356 mm, round to 360 mm
= 14 + 3 = 17 in
= 432 mm, round to 430 mm
Below Tray No. 28
Drawoff Nozzle Diameter = 18 in
= 1.5 (18) = 27 in
= 686 mm, round to 690 mm
= 18 in
= 457 mm, round to 460 mm
= 18 + 3 = 21 in
= 533 mm, round to 530 mm
Distributor Traps (Form F-PSD-17)
Below Tray No. 3 Trap Type F
Liquid Rate from Trap = = 1094 gpm (Attachment 2, sheet 18).
= 229 + 4 (25.4) = 331 mm, round to 330 mm
= 13 in
how = 0.4 = 3.08 in, 4 in. is adequate for
Below Tray No. 17 Trap Type F
Liquid Rate from Trap = = 1661 gpm (Attachment 2, sheet 18).
= 229 + 4 (25.4) = 331 mm, round to 330 mm
= 13 in
how = 0.4 = 4.07 in
4.07 + 0.5 = 4.57 in
= 116 mm, round to 120 mm for
Below Tray No. 25 Trap Type F
Liquid Rate from Trap = = 1288 gpm (Attachment, sheet 19).
= 229 + 4 (25.4) = 331 mm, round to 330 mm
= 13 in
how = 0.4 = 3.4 in, 4 in. is adequate for
Disc and Donut Pans (Form F-PSD-19)
Diameter = = 17.6 ft
= 5364 mm, round to 5360 mm
= 600 + 4 (25.4) = 702 mm, round to 700 mm
Diameter = = 12.45 ft
= 3795 mm, round to 3800 mm
= 0.5 ( - ) = 0.5 (5360 - 3800) = 780 mm
= 0.5 = 1.67 ft
= 509 mm, round to 510 mm
= 0.5 (7600) - 0.5 - = 3800 - 2680 - 510 = 610 mm
Attachment 1 Index Example
| Name of Vessel Main Column | Name of Vessel Main Column | Name of Vessel Main Column | Name of Vessel Main Column | Name of Vessel Main Column | Name of Vessel Main Column | Name of Vessel Main Column | Name of Vessel Main Column | Name of Vessel Main Column | Item No 912-C 601 | Item No 912-C 601 | Item No 912-C 601 | Item No 912-C 601 | Item No 912-C 601 | Item No 912-C 601 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | Notes | Notes | |||||||||||||
| Item | Item | Quan | ID of | Material | Description | Dwg or | Tray | Tray | Tray | (Sheet | (Sheet | ||||
| No | No | Assem | Vessel | Sht No | No | No | No | 2&3) | 2&3) | ||||||
| 1,3 CDD | |||||||||||||||
| 1 | 10 | 7600 | 410 | Valve Trays | 9, 10 | 9, 10 | 7-17 | 2X, 26 | 2X, 26 | 2X, 26 | |||||
| 21, 23 | |||||||||||||||
| 2, even | |||||||||||||||
| 2 | 8 | 7600 | 410 | Valve Trays | 9, 10 | 9, 10 | 8-16, | 2, 26 | 2, 26 | 2, 26 | |||||
| 22, 24 | |||||||||||||||
| M=50; N= 40 | M=50; N= 40 | M=50; N= 40 | M=50; N= 40 | Below | |||||||||||
| 3 | 2 | 7600 | 410 | Traps | 3-204 | 3-204 | W=150; Y=330 | W=150; Y=330 | 3 | ||||||
| 9 | 9 | ||||||||||||||
| 4 | 2 | 7600 | 410 | Valve Trays | 9 | 9 | 4, 6 | 4X, 26 | 4X, 26 | 4X, 26 | |||||
| 5 | 1 | 7600 | 410 | Valve Tray | 9 | 9 | 5 | 4, 26 | 4, 26 | 4, 26 | |||||
| 3-280 | 3-280 | Below | |||||||||||||
| 6 | 3 | 7600 | 410 | Traps | 9 | 9 | 6 | ||||||||
| 3-298 | 3-298 | A=1600; C=2.72M2 | A=1600; C=2.72M2 | A=1600; C=2.72M2 | A=1600; C=2.72M2 | Below | |||||||||
| 7 | 1 | 7600 | 410 | Accumulator | Type IV | Type IV | G=610; H=410; J=480 | G=610; H=410; J=480 | G=610; H=410; J=480 | G=610; H=410; J=480 | 6 | 7, 18 | 7, 18 | 7, 18 | |
| 3-204 | 3-204 | M=50; N=40 | M=50; N=40 | M=50; N=40 | M=50; N=40 | Below | |||||||||
| 8 | 1 | 7600 | 410 | Trap | 9 | 9 | W=170; Y=330 | W=170; Y=330 | 17 | ||||||
| 9 | 2 | 7600 | 410 | Valve Trays | 9 | 9 | 18, 20 | 4X, 26 | 4X, 26 | 4X, 26 | |||||
| 10 | 1 | 7600 | 410 | Valve Tray | 9 | 9 | 19 | 4, 26 | 4, 26 | 4, 26 | |||||
| 3-280 | 3-280 | Below | |||||||||||||
| 11 | 3 | 7600 | 410 | Traps | 9 | 9 | 20 | ||||||||
| 3-298 | 3-298 | A=950; C=2.72M2 | A=950; C=2.72M2 | A=950; C=2.72M2 | A=950; C=2.72M2 | Below | |||||||||
| 12 | 1 | 7600 | 410 | Accumulator | Type IV | Type IV | G=530; H=360; J=430 | G=530; H=360; J=430 | G=530; H=360; J=430 | G=530; H=360; J=430 | 20 | 7, 16 | 7, 16 | 7, 16 | |
| 25, 29, | |||||||||||||||
| 13 | 4 | 7600 | 410 | Valve Trays | 10 | 10 | 31,33 | 2X, 5, 26 | 2X, 5, 26 | 2X, 5, 26 | |||||
| 3-204 | 3-204 | M=50; N=40 | M=50; N=40 | M=50; N=40 | M=50; N=40 | Below | |||||||||
| 14 | 1 | 7600 | 410 | Trap | 10 | 10 | W=150; Y-330 | W=150; Y-330 | W=150; Y-330 | W=150; Y-330 | 25 | 5 | 5 | 5 | |
| 15 | 2 | 7600 | 410 | Valve Trays | 10 | 10 | 26, 28 | 4X, 5, 26 | 4X, 5, 26 | 4X, 5, 26 | |||||
| 16 | 1 | 7600 | 410 | Valve Tray | 10 | 10 | 27 | 4, 5, 26 | 4, 5, 26 | 4, 5, 26 | |||||
| 3-280 | 3-280 | Below | |||||||||||||
| 17 | 3 | 7600 | 410 | Traps | 10 | 10 | 28 | 5 | 5 | 5 | |||||
All sections shall pass through a 30” ID vessel manway.
Attachment 1 Index Example (cont)
| Service Main Column | Service Main Column | Service Main Column | Service Main Column | Service Main Column | Service Main Column | Service Main Column | Service Main Column | Service Main Column | Item No 912-C 601 | Item No 912-C 601 | Item No 912-C 601 | Item No 912-C 601 | Item No 912-C 601 | Item No 912-C 601 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | Notes | Notes | |||||||||||||
| Item | Item | Quan | ID of | Material | Description | Dwg or | Dimensions | Dimensions | Dimensions | Dimensions | Tray | Tray | Tray | (Sheet | (Sheet |
| No | No | Assem | Vessel | Sht No | No | No | No | 2&3) | 2&3) | ||||||
| 3-288 | 3-288 | A=1950; C=2.72M2 | A=1950; C=2.72M2 | A=1950; C=2.72M2 | A=1950; C=2.72M2 | Below | |||||||||
| 18 | 1 | 7600 | 410 | Accumulator | Type IV | Type IV | G=690; H=460; J=530 | G=690; H=460; J=530 | G=690; H=460; J=530 | G=690; H=460; J=530 | 28 | 7, 18 | 7, 18 | 7, 18 | |
| 19 | 2 | 7600 | 410 | Valve Trays | 10 | 10 | 30, 32 | 2, 5, 26 | 2, 5, 26 | 2, 5, 26 | |||||
| Donut Pan | 3-252 | 3-252 | |||||||||||||
| 20 | 1 | 7600 | 410 | with Weir | 10 | 10 | 34 | 5, 27 | 5, 27 | 5, 27 | |||||
| 3-252 | 3-252 | D=25; P=1900 | D=25; P=1900 | D=25; P=1900 | D=25; P=1900 | ||||||||||
| 21 | 3 | 7600 | 410 | Disc Pan | 10 | 10 | R=45; U=2680, V=90 | R=45; U=2680, V=90 | R=45; U=2680, V=90 | R=45; U=2680, V=90 | 35, 37, 39 | 5 | 5 | 5 | |
| Donut Pan | 3-252 | 3-252 | D=25; Q=3290; R=45 | D=25; Q=3290; R=45 | D=25; Q=3290; R=45 | D=25; Q=3290; R=45 | |||||||||
| 22 | 2 | 7600 | 410 | without Weir | 10 | 10 | U=2680, V=90 | U=2680, V=90 | U=2680, V=90 | U=2680, V=90 | 36, 38 | 5 | 5 | 5 | |
Notes: 27) A=600, D=25, Q=3290, R=45, T=3200, U=2680, V=90, W=75
All sections shall pass through a 30" ID vessel manway.
Attachment 2 Loading Specifications Example
| Service: Main Column | Service: Main Column | Service: Main Column | Item Number: 912-C601 | Item Number: 912-C601 |
|---|---|---|---|---|
| Tray Data | Tray Data | Type of Unit: RCC | Type of Unit: RCC | Type of Unit: RCC |
| Tray Identification (Tray Numbers) | TOP 1-3 | NAPHTHA PUMP- AROUND 4-6 | BELOW NAPHTHA DRAW 7-17 | LCO PUMP- AROUND 18-20 |
| Vessel ID, mm (minimum) | 7600 (min) | 7600 (min) | 7600 (min) | 7600 (min) |
| Operating Pressure, kg/cm2(g) | 0.99 | 1.05 | ||
| Operating Temperature, C | 129 | 143 | ||
| Structural Design Temperature, C | 388 | 388 | 388 | 388 |
| Fluid Description | HCBN | HCBN | HCBN | HCBN |
| Foam Derating Factor | 1.0 | 1.0 | 1.0 | 1.0 |
| Vapor -Flow Rate, kg/h | 466096 | 556909 | 556909 | 562258 |
| Density, kg/m3 | 3.52 | 3.94 | 3.94 | 3.68 |
| Liquid -Flow Rate, kg/h | 180582 | 930410 | 271396 | 526180 |
| Density, kg/m3 | 726.8 | 719.8 | 719.8 | 784.7 |
| Viscosity, cP | 0.32 | 0.302 | 0.302 | 0.353 |
| Surface Tension, dynes/cm | 16.7 | 16.7 | 16.7 | 17.3 |
| Type of Tray | Valve | Valve | Valve | Valve |
| For Sieve Trays | ||||
| Weir Height, M, mm | ||||
| Downcomer Clearance, N, mm | ||||
| Total Number of Holes | ||||
| Hole Diameter, mm | ||||
| Hole Area/Bubbling Area x 100 | ||||
| Tray spacing, S mm (for exceptions see Project Specification 301 Vessels) | 600 | 600 | 600 | 750 |
| Notes | ||||
| Tray Layout | ||||
| Number of Passes | 2 | 4 | 2 | 4 |
| A, mm (minimum) | 600 (min) | 752 (min) | 600 (min) | 752 (min) |
| B, mm | 2972 | 1352 | 2972 | 1352 |
| C, mm (minimum for 1 pass) | 456 | 229 | 456 | 229 |
| D, mm | 1352 | 1352 | ||
| E, mm | 230 | 230 | ||
| F, mm | ||||
| G, mm (minimum) |
Attachment 2 Loading Specifications Example
| Service: Main Column | Service: Main Column | Service: Main Column | Item Number: 912-C601 | Item Number: 912-C601 |
|---|---|---|---|---|
| Tray Data | Tray Data | Type of Unit: RCC | Type of Unit: RCC | Type of Unit: RCC |
| Tray Identification (Tray Numbers) | BELOW LCO DRAW 21-25 | HCO PUMP- AROUND 26-28 | BELOW HCO DRAW 29-33 | BOTTOM 34-39 |
| Vessel ID, mm (minimum) | 7600 (min) | 7600 (min) | 7600 (min) | 7600 (min) |
| Operating Pressure, kg/cm2(g) | 1.12 | 1.20 | 1.26 | |
| Operating Temperature, C | 232 | 288 | 360 | |
| Structural Design Temperature, C | 388 | 565 | 565 | 565 |
| Fluid Description | HCBN | HCBN | HCBN | HCBN |
| Foam Derating Factor | 0.9 | 1.0 | 1.0 | 1.0 |
| Vapor -Flow Rate, kg/h | 562258 | 678506 | 678506 | 359979 |
| Density, kg/m3 | 3.68 | 3.88 | 3.88 | 1.91 |
| Liquid -Flow Rate, kg/h | 226884 | 933348 | 339693 | 584553 |
| Density, kg/m3 | 775.7 | 843.6 | 807.7 | 837.7 |
| Viscosity, cP | 0.331 | 0.394 | 0.304 | 0.331 |
| Surface Tension, dynes/cm | 16.4 | 19.2 | 15.8 | 16.3 |
| Type of Tray | Valve | Valve | Valve | Disc & Donut |
| For Sieve Trays | ||||
| Weir Height, M, mm | ||||
| Downcomer Clearance, N, mm | ||||
| Total Number of Holes | ||||
| Hole Diameter, mm | ||||
| Hole Area/Bubbling Area x 100 | ||||
| Tray spacing, 5 mm (for exceptions see Project Specification 301 Vessels) | 600 | 750 | 600 | 900 |
| Notes | ||||
| Tray Layout | ||||
| Number of Passes | 2 | 4 | 2 | - |
| A, mm (minimum) | 600 (min) | 752 (min) | 600 (min) | |
| B, mm | 2972 | 1352 | 2972 | |
| C, mm (minimum for 1 pass) | 456 | 229 | 456 | |
| D, mm | 1352 | |||
| E, mm | 230 | |||
| F, mm | ||||
| G, mm (minimum) |
Attachments
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