Vessel Internal Components Installation Method
Support Ring Installation and Level Reading Method
Support ring installation shall be done on a level wise stage. Install the support ring precisely on the internal of vessel equipment. Check for the orientation of the support ring. The support ring levelness shall be checked by using a 12mm
manometer hose level or its equivalent.
The measurements for the levelness of the support ring should be checked at a minimum of 5 points, 1 in the middle and
1 at each corner for each pass. Tolerance is ±3mm (vendor requirement). If the tray levelness is over the tolerance value, provide shims on the tray support ring and weld as per Saudi Aramco Specifications (SAES-W-010).
WPS for dissimilar base metals shall be use. Levelness for the outlet weir should be checked at a minimum of 3 points, 1 at each end and 1 at the center. Once it is leveled, marked, weld and tightened the bolt to stabilize its position. It is now possible to start Tray Installation.
Tray Installation
Tray installation shall be done on a level wise stage starting from the lowest level. Components shall be ensured its cleanliness and completeness before installation. Clean the portion of inside shell of dust and other foreign particles.
From the pre-assembled parts on the ground, start to install it on the internal of vessels. Carefully assemble and place the component the same way it was on ground.
Start bolting the components to ensure stability. Once the assembly of tray on the first level is completed, clean the portion of internal surface of shell where the second level of tray may be assembled.Place a sheet of non combustible material on the completed first level tray to ensure its cleanliness of dust and other foreign particles.
Continue doing the same process untill completion of tray installation. Always check and double check the tray identification and orientation to ensure continuity of installation work inside the equipment vessel. Ensure that gaps and spacing of individuals are correct and is based on the latest IFC drawing.
Structured Packing
Segmented Structured Packing
Check bed height of tower attachment and record the dimension. Prior to put into the tower, do a trial assembly of at least one layer of structured packing on the ground so the workers easily understand the configuration of the packing. A wall wiper banding should be bent in order to as per drawing prior to assemble.
Install the bottom layer on packing support in accordance with drawing as confirming the piece mark and the orientation. Segmented structured packing consists of pre cut multiple sections with a radius on peripheral pieces to conform to the tower wall.
Each section is fabricated from parallel layers of structured packing material with opposing angles of corrugations which are held securely together to form a rigid brick. In order to prevent damage, special care should be taken while handling the sections.
The installation positioning plate is an inverted “L” shaped light thickness metal piece. The peripheral segments are the first sections to be installed on the support grid and slide firmly up against the tower wall. Place the positioning plate against this section and then tap it horizontally along its length to secure the piece in place.
Remove the first and repeat around the tower installing outer sections, working inward to the center of the tower. A gap of approximately 50 mm to 70 mm will remain between the last two rows of installed sections.
Fill this remaining void with single filler material of structured packing. Sandwich these filler material between positioning plates on each side of the gap to facilitate installation and avoid damage.
Each layer of packing is designed to compensate of normal tower out of roundness. If tower diameter is on the negative side, it is possible the gap described in the previous paragraph will be eliminated. Should this occur, secure the positioning plates against the last sections installed before sliding the final section into place.
As each final section is centered over its space, compress the lower edge inward with finger pressure tight, place a plywood plate on top of the section and apply body weight to set the section without deforming the structured packing. After the final sections are place, remove the positioning plates and plywood before installing the next unit.
Parallel layers of adjacent structured packing units must be rotated 90 degree to each other. The supplied “Elevation and Orientation” drawing must be provided for further details. While packing the column, eliminate the accumulation of debris by checking the top of each layer of packing across the entire area of the tower before commencing with the installation of the next desired overall performance.
One-Piece Layer Structured Packing
One-piece layer structured packing are generally used for columns with an outside diameter of 24″ or less. In preparation of the installation of one-piece layers of structured packing, an installation tool consisting of a push rod welded (or otherwise securely attached) to a face plate (or plywood disk) should be prepared.
The face plate should be approximately 25 mm or 50 mm less than the column inside diameter. The handle of the rod tool should be long enough to travel the necessary distance to push the bottom layer against the support grid.
Verify that the push rod travels freely down the column and does not encounter interference by weld slag, nozzle internal projections or any tower deformities. As each unit is installed, bend the clipped wiper band portion out horizontally to prevent liquid and vapor by-passing at tower shell.
The bottom band is wrapped under the unit and indicates the bottom side of the unit. Place a unit, holding the structured packing carefully to prevent it from falling, at the top oft e column and work the bottom of the unit into the column using the edge or flat of the hand to center the unit.
Push the unit carefully and slowly into the column, being sure not to snag or tear bands loose from the unit. Use the push rod assembly when the unit is fully in the column, to move the unit to the support grid or last unit installed, When reaching
the bottom, gently tap the unit to seat it in place.
With the aid of a straight edge placed on the flange face, make a mark on the push rod to indicate the distance remaining. It will be possible to determine, by carefully checking from mark, that the units are properly seated without using excessive force on the push rod. Continue this process until all units have been installed.
Be certain that no foreign matter enters the column between units. Check the elevation after installation of each unit. Random Packing During installation, special care must be taken to not damage the packing.
When personnel are required to work inside the column, planks and/or plywood may be used to distribute the weight of the personnel to minimize damage to the packing. At a minimum weight of each person should be distributed over approximately 4 square feet (0.5 m2) of area.
Always take precautions to make sure personnel use the proper PPE as the packing can sharp. A chute and sock are required to properly install the packing through the vessel man way. During the installation of the bed of random packing, special care must be taken to ensure none of the planks or plywood used to distribute the weight of personnel is left in the packed bed.
In addition, constant care must be taken to ensure no debris of any type is allowed to remain in the packed bed. Any construction tools or debris remaining in the packed bed can affect the packing. Extra care must be taken when installing
plastic random packing as the plastic packing is typically lower than its metal counterparts, and it can be temperature at the time of installation.
Check the levelness of the random packing support plate and its relative elevation and orientation. Carefully spread the random packing evenly on the random packing support plate to a depth of 250 mm-300 mm. This should be done while standing on the support plate and serves to minimize the damage that might occur if the packing was dropped from the vessel man way.
After the initial amount of packing is installed, begin pouring the remaining packing into the column through the vessel man way if the vessel man way is less than 3 meters above the packed bed. The packing must be evenly scattered over the entire area of the column thus ensuring an even distribution. At no time should the packing level in the bed deviate more than 750 mm from the horizontal.
Otherwise, begin leveling activities to correct the situation before continuing to pour packing into the column. If the vessel man way is more than 3 meters above the packed bed, it is recommended that the installation of the remainder of the packing be done with a chute and sock or some other means to minimize the damage created by a large falling distance. When a chute and sock are required, it is recommended that the maximum distance from the bottom of the sock to the top of the bed not exceed 2.4 meters.
The maximum distance from the bottom of the sock to the top of the bed should not be less than 0.6 meters. For columns 16 meters in diameter and smaller, the sock should be located on the vertical centerline of the vessel and should not need to be relocated to evenly distribute the packing in the bed. In columns larger the 1.5 meters in diameter, the sock should be re positioned as necessary evenly distribute the packing throughout the bed. When the top of the bed is within 1.5 meters of the vessel man way, the chute and sock may be removed and the remainder of the packing can be poured in, paying attention to maintain level during the installation.
When the packing reaches the appropriate bed height it should be carefully leveled. This may be accomplished by lightly raking the packing until it is level. When a separate “column supported” bed limiter is utilized, it should rest on the tower attachments With the packing almost touching the bed limiter. When a separate “floating” bed limiter is utilized, it should rest on top of the packed bed. At no time should personnel working inside the column be directly on the packing. Their weight must be evenly distributed over approximately 0.5 m2 at all times.
Random Packing Bed Limiter (when required)
The random packing bed limiter is typically supported from tower attachments on the column wall or it may rest on the top of the packed bed. Be sure to center the entire bed limiter in the column. The orientation of the random packing bed limiter to the distributor can be critical as it may affect the liquid distribution from the distributor onto the packing. Be sure to verify the proper orientation of the random packing bed limiter to the distributor with the vendor drawings provided.
Distributors
The lower attachments that support the distributor must be checked for levelness. The distributor can be supported by support beams, and/or vessel support rings. Be sure to keep the distributor centered in the column to keep the feed hole pattern properly locate. Be sure to verify proper orientation of the distributor with the vendor drawings provided. Distributor performance is closely tied to distributor, so make sure that the distributor has been properly leveled. General guidelines for the minimum distributor levelness shall be provided by the vendor. For deck type or flange liquid distributor designs, refer to the drawings provided by the vendor and ensure any and all gasket material is properly installed where indicated.
Collectors/Chimney Trays
The tower attachments that support the collector must be checked for levelness to ensure collector is installed correctly. If the collector has a down-comer, make sure the clearance between down comer and the internals located below is correct. The orientation of the collector is critical relative to the other internals and to the column itself. Be sure to verify the proper orientation of the collector/chimney trays with the vendor drawings provided.
Bolting Method
Once the assembly of individual trays is completed, bolts shall be tightened using a calibrated torque wrench. Prior to using torque wrench, bolts shall be initially tightened by using hands/fingers, Ensure that no force fit on bolts shall happen that it will damage thé bolt thread once being torque by wrench on the final stage of bolt tightening. Recommended bolt torque value by the vendor is 1.0kgf-m to 1.7kgf-m.
Welding Method on Vessel Internal Components
Welding method on vessel internal components shall be done with approved vendor WPS or WPS approved by the COMPANY. Safety procedure shall be taken into consideration as always. Ensure that slags and fumes shall be removed by safety means during the course of the welding activity. Ensure that all cables and materials for welding shall not contaminate the assembled trays installed inside the vessels. Outmost care shall be observed especially on the falling melted slags. Adequate fire blanket must be provided in the entire duration of the welding activity.
Notes:
1) Any conflict between the vendors drawing and the physical equipment must be resolved by contacting the vendor’s representative.
2) All equipment bolting should properly torque, but be careful not to over tighten as damage to the equipment may result. A thread lubricant may or may not be used based upon individual process requirements.
3) It is critical throughout the installation of random packing and intemals that a close watch is kept on all installation tools and equipment. Make sure all of these items are removed from the column before closing the vessel man-ways as they can affect the performance of the equipment.
Leak Test Method
Once the entire installation of vessel intemals trays are completed, final inspection shall be made to ensure completeness of the installation. After inspection and acceptance of the responsible personnel, leak testing of assembled trays will commence.
Third party certified demineralized water shall be use for the leak test. Chloride content of the demineralized water shall not exceed 50 ppm. The water level shall not drop by more than 25 mm after 1 hour and 15 minutes of testing to pass the acceptance criteria for leak test. All trays shall be thoroughly dried after the leak testing.
Box Up/ Vessel Final Closure
After completion of the inside vessel tray installation, leak testing and cleaning requirements, final inspection shall be made by concemed padies. Once completed inspections and acceptance were done, immediately close the manholes. Apply the required torque value on the bolts of manhole flange. Preservation shall be decided either Nitrogen or VpCl as the project progresses. Notice shall be given to Mechanical Department should final piping connections will be done.
EQUIPMENT, TOOLS AND CONSUMABLES
1. Crane for special lift
2. Slings and soft tag lines
3. Davit arm and rope pulley assembly
4. Manometer hose or its equivalent hose
5. Feeler gauges and calipers
6. Calibrated torque wrench
7. Coverall and shoe cover
8. Calibrated gas detectors
9. Fans/blowers of sufficient capacity
10. Lightings of sufficient illumination
11. Welding materials
INTERNATIONAL STANDARD REFERENCES
REIE 686 Recommended Practices for Machinery Installation and Design
ASME Sec.VIII D1 & D2 Rules for Construction of Pressure Vessels
I want to know more about the Tray Installation to be sure as per API Procedure.
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