Table of Contents
| Section | Title | Page |
| Purpose | 2 | |
| Scope | 2 | |
| Related Documents | 2 | |
| Extent of Supply | 2 | |
| Design and Construction—Pressure Vessel | 3 | |
| Screens—Support, Sealing, and Fixing | 4 | |
| Floating Screens | 9 | |
| Gas Sampling Probes | 9 | |
| Internal Filter | 10 | |
| Adsorbents | 10 | |
| Cleaning | 10 | |
| Painting of External Surfaces | 10 | |
| Inspection and Quality Plan | 10 | |
| Lifting and Transport | 11 | |
| Calculations | 11 | |
| Information To Be Supplied With The Bid | 11 | |
| Change Log | 12 | |
| Installation of Nozzle Screen (Typical Horizontal and Vertical Vessels) | 13 | |
| Basic Details of Rope Packed Joint (Vertical Vessel) | 14 | |
| Basic Details of Rope Packed Joint (Horizontal Vessel) | 15 | |
| Approved Details for Bed Support Plate Edge (Horizontal and Vertical Vessels) | 16 | |
| Approved Details of Support Beam Rope Packed Joint (Horizontal Vessel) | 17 | |
| Approved Details of Support Plate Fixed Joint (Horizontal Vessel) | 18 | |
| Approved Details of Support Plate Bolted Joint (Horizontal Vessel) | 19 | |
| Approved Details of Rope Packing Corner Joint (Horizontal Vessel) | 20 | |
| Details of Rope Packing Retaining Plates (Horizontal Vessel) | 21 | |
| Details of Support Beam Studding (Horizontal Vessel) | 22 | |
| Details of Support Plate Lifting Lugs (Horizontal and Vertical Vessels) | 22 | |
| Details of Support Beams and Support Brackets (Horizontal Vessels) | 23 | |
| Details of Support Beam Upper Web Guide Blocks (Horizontal Vessels) | 24 | |
| Detail of Bed Support Skirt and Legs (Vertical Vessels) | 25 | |
| Detail of Bed Cover Plate Joint Details (Vertical Vessels) | 26 | |
| Alternative Arrangement for Bed Support Ledge (Horizontal Vessel) (alternative to Figure 3) | 27 | |
| Final Inspection (Horizontal and Vertical Vessels) | 28 | |
| Alternative Details for Bed Support Plate in Dished Ends of Horizontal Vessels | 30 | |
| Gap Between Support Beam and Screen Plate Stiffener (Horizontal and Vertical Vessels) | 31 | |
| Nozzle Screen Protection Grating (Horizontal and Vertical Vessels) | 32 | |
| Sample Calculation for Required Quantity of Rope Packing | 33 |
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1. PURPOSE
1.1 This global engineering specification defines the minimum requirements for the supply of horizontal and vertical temperature swing molecular sieve adsorber pressure vessels with nozzle-type screens, hereinafter referred to as TSA vessels.
2. scope
2.1 This specification covers the design, fabrication, cleaning, painting, internal treatment, inspection, and documentation requirements specific to TSA vessels with nozzle screens. It shall be read in conjunction with 4WEQ-1070, the vessel Setting Plan, the Project Equipment Specification (PES), the requisition and its attachments.
3. related documents
3.1 Air Products Engineering Documents 4WEQ-1010 Supplier-Designed, Shop-Fabricated Pressure Vessels 4WEQ-1070 Temperature Swing Adsorber Vessels (General Requirements) 4WEQ-6804 Painting and Corrosion Protection of New Construction for Design Temperatures to 649°C (1200°F) Setting Plan The Vessel Setting Plan is a general drawing showing key dimensions and design features, but lacking full fabrication details and dimensions. PES Project Equipment Specification QCP Equipment Quality Control Plan
Note: When reference is made in this document to the requisition, it shall be taken to include all attachments.
3.2 Air Products Purchasing Documents Purchase Order (PO) and its attachments DOC0000657799 TSA vessel inspection
3.3 British Standards Institute (BSI) PD 5500 Unfired Fusion Welded Pressure Vessels
3.4 DLA-GS5 – Defense Supply Center, Richmond RR-C-271D Chains and Attachments, Welded and Weldless
4. EXTENT OF SUPPLY
4.1 The supplier is responsible for providing all materials, plant and labour associated with the mechanical design, supply of fully checked and approved manufacturing drawings and calculations, manufacture, testing, cleaning, internal coating*, painting, installation of internals, sliding saddle base plate and low friction pads*, gas sampling probes, internal floating screens*, and packing for transport of the vessels in strict accordance with the Air Products PES and the PO. * When it is specified in PES.
4.2 Nozzle screens, split washers, and round nuts and the rope packing and RTV for the bed support plate seal will be supplied free issue by Air Products. The scope of supply shall include for the fitting of these nozzle screens and installing rope packing and for all materials associated with the fitting.
4.3 The supplier shall provide the vessel with service gaskets fitted in all flanged joints that will not be opened during installation/commissioning. Flanged joints that will be broken during the vessel’s installation/commissioning may be supplied with generic/test gaskets installed (for example, manways, adsorbent fill nozzles, or air inlet/outlet nozzle).
4.4 The supplier shall provide two spare gaskets for each manway and fill nozzle and 10% spare bolting for each size manway and fill nozzle.
5. DESIGN AND CONSTRUCTION—PRESSURE VESSEL
5.1 Design/Construction—General
5.1.1 The pressure vessel design shall be as specified in the PES, 4WEQ-1070, the setting plan drawing and the requisition attachments.
5.1.2 The general features of a nozzle screen type TSA vessel are shown in the setting plan attached to the requisition. The setting plan should be used as a basis of design by the vessel fabricator. Deviations from the design features shown on the setting plan and this specification require Air Products approval.
5.1.3 The Air Products setting plans for vertical vessels shall contain: An outline of the vessel showing overall size (for example, tangent-to-tangent length, height, diameter, and critical minimum thicknesses). Details of all nozzles: size, schedule, rating, location, and projection, including vents and drains. Details of the vessel support skirt, including required anchor bolt size and base plate thickness. A layout of the bed support plate, showing the position of all nozzle screens. Minimum requirements for the bed support skirt and legs (if applicable). Vessel insulation thickness and support ring requirements Total weight of Adsorbent
5.1.4 The Air Products setting plans for horizontal vessels shall contain: An outline of the vessel showing overall size (for example, tangent-to-tangent length, height, diameter and critical minimum thicknesses). Details of all nozzles: size, schedule, rating, location, and projection, including vents and drains. Details of saddle supports, including required anchor bolt size, base plate thickness, and fixed and free saddles. A layout of the bed support plates, showing position of all nozzle screens. Minimum requirements for the bed support beams. Details of sliding end saddle PTFE plate and fixed end saddle packer plate. Vessel insulation thickness Total weight of Adsorbent
5.1.5 The lower shell course of vertical vessels that contains the bed plate support ring must be fabricated to diameter and ovality tolerances exceeding pressure vessel code requirements to satisfy the rope seal gap tolerances specified in Figure 2.
5.1.6 The air inlet nozzle shall be provided with a perforated impingement plate as shown in the vessel setting plan. The impingement plate shall be made of austenitic stainless steel and be removable. Any bolting used to attach the impingement plate shall be locked by means of tack welding.
5.2 Design/Construction for Fatigue
5.2.1 See 4WEQ-1070.
Note: Unless specified otherwise in the PES, Air Products will perform the fatigue analysis and specify the minimum thicknesses of shell and heads.
5.3 Corrosion Allowance
5.3.1 The internal surfaces of the TSA vessel pressure envelope shall have a corrosion allowance of 1.5 mm minimum. If “extended service” TSA vessels (as defined in 4WEQ-1070) are specified in the PES, the corrosion allowance on the internal surface of the pressure envelope shall be increased to 3 mm minimum.
5.3.2 See paragraph 6.2.4 for corrosion allowance requirements for internal attachments.
6. SCREENS – SUPPORT, SEALING, AND FIXING
6.1 General
6.1.1 The nozzle screen adsorbent bed support system is used on both vertical and horizontal TSAs. The common feature of the design is that the adsorbent bed is supported on a flat horizontal plate (bed support plate) into which are set many ‘nozzle screens’ on a regular square pitch. The bed support plate carries the weight of the adsorbent bed and is in turn supported from the vessel wall. The feed air enters the vessel from below the bed support plate and passes into the nozzle screens through their centre tail pipes, and then through the v-wire screen in each nozzle into the adsorbent. At times during the TSA operating cycle, the bed support plate will have a different temperature to that in the vessel. For this reason, the bed support plate cannot be rigidly attached to the vessel wall; instead it rests on a ledge at the inside surface of the vessel. For larger vessels, the plate is also supported by cross beams (for horizontal vessels) or cylindrical skirts and props (vertical vessels). The design of these supports must be validated for each application. At the edge of the bed support plate is a seal system so that the plate can slide over the support ledge without allowing adsorbent to work its way through any small gaps that may exist. The design of this seal and sliding joint has been standardized and no changes shall be made without written approval of the Air Products Technology Manager.
6.1.2 Details of the nozzle screens will be supplied by Air Products when the vessel order is placed. The vessel supplier shall install the nozzle screens in accordance with Figure 1.
6.1.2.1 The vessel supplier shall inspect all nozzle screens for signs of damage as they are fitted. Suspect nozzle screens shall not be installed and be quarantined for Air Products inspection.
6.1.2.2 Approximately 25 spare nozzle screens remaining after the supplier has installed the required number in each vessel, shall be packaged with any other specified spares, for shipment (in case any nozzles are damaged during adsorbent loading). Any remaining spare nozzle screens shall be kept pending Air Products instructions.
6.1.3 The basic design of the seal system at the edge of the bed support plate is shown in Figure 2 (vertical vessels) and Figures 5 and 8 (horizontal vessels).
6.1.4 The edge seal is filled with fibreglass rope by the vessel supplier in his shops. The rope packing shall be installed after the vessel has been cleaned and dried following its hydrotest. The packing shall be to material specification RLGxx where xx=the nominal rope diameter. This material is available from: THS Industrial Textiles Heathfield Business Park Heathfield Street Elland, West Yorks, HX5 9AU, UK Tel: +44 (0)1422 311607, Fax: +44 (0)1422 387316, mail@thstextiles.co.uk
6.1.5 The basis of determining the number of rope turns (total rope cross sectional area) required for a given edge seal volume is based on the requirement for the volumetric compression of the rope seal to be kept within the bounds of 80% of original uncompressed volume in the ‘cold’ installed condition and 50% of original uncompressed volume under maximum operating conditions. Tests performed by Air Products have shown the material (HTP grade GR3 or RLG30) to exhibit good recovery when operated in this range. Alternative rope materials may require a different design basis. For this reason alternative materials are not acceptable.
6.1.5.1 For Horizontal vessels with largest linear dimension of screen plate <5000 mm (that is either screen plate length or width) and Vertical vessels with diameter of screen plate <5000 mm, for the rope seal gap geometry specified in this document (seal gap width=30 +5/-5 mm, seal gap height = 85 +1/-0 mm) and a design metal temperature difference of 100°C (180°F) between the vessel wall and the bed support plate, 3 ‘turns’ of 40 mm diameter rope packing is required.
6.1.5.2 If there are changes to any of the seal key dimensions or tolerances, or if the temperature difference changes, the required rope quantity shall be recalculated. A sample calculation is shown in Appendix A.
6.1.5.3 The rope packing shall be purchased by the vessel manufacturer. To allow for rope gap width deviations, ‘spare’ rope shall be purchased as indicated in the following table. Rope seal is normally supplied in 30 m rolls.
| No. of turns per vessel | Rope diameter (mm) |
| 1 spare | 35 |
| 1 spare | 25 |
| 1 spare | 20 |
| 1 spare | 15 |
6.1.6 Small gaps (when accepted by Air Products) in the screen seal system are closed using high temperature [260°C (500°F) continuous, 315°C (599°F) intermittent], silicon sealant commonly known as ‘RTV’ (see Figure 15 Note 4) . ‘RTV’ shall be purchased by the vessel manufacturer. The following grades of ‘RTV’ are approved for use in TSA vessels (supplied in 310 ml cartridges): Momentive Performance Materials Products ‘RTV 106’ https://www.momentive.com/Products/home.aspx?id=20785 Dow Corning ‘736’ Heat Resistant Sealant http://www.dowcorning.com/applications/search/default.aspx?R=396EN Loctite ‘5399’ http://www.loctite.co.uk/cps/rde/xchg/SID-0AC83309-C7939D52/henkel_uke/hs.xsl/3185_UKE_HTML.htm?countryCode=uke&BU=industrial&parentredDotUID=productfinder&redDotUID=1000000IWN5
6.1.7 All bolting inside the vessel shall be austenitic stainless steel with the nuts being a different grade stainless to the bolting/studding (for example, 304 and 316) to avoid galling. All bolting shall be M16 (or 5/8″ UNC) minimum. All internal bolting shall be provided with heavy stainless steel washers.
6.1.8 Unless specified otherwise the minimum leg length of fillet welds shall be 6 mm.
6.1.9 A protective grating as defined in Figure 18, shall be installed above the bed support plate, directly below all manways.
6.2 Design of Bed Support Plate—The bed support plate and the seal edge bars welded to it, shall be carbon steel SA516 grade 70 or equivalent. The supporting structure under the plate shall be structural steel SA36 or better. Support rings/brackets/skirts that are welded to the vessel pressure parts shall be compatible with the vessel material.
6.2.1 Bed Support Plate Loading—The deadweight of the adsorbent bed is taken to act over the area of the bed support plate as an equivalent pressure load. This is calculated by taking the total weight of bed and dividing it by the plan area of the plate. During normal feed, the gas flows upwards through the bed. During regeneration, hot gas flows downwards through the bed. There is a small pressure drop across the bed and across the support plate in both feed and reactivation. Unless specified otherwise the bed support plate and supports will be designed and specified by Air Products.
6.2.1.1 The plate design and its support structure including local attachments to the vessel wall are based on two cases: Case 1—Downwards loading: 0.345 bar (5.0 psi) pressure drop across the bed support plate and adsorbent bed in the downwards direction, with the vessel at the regeneration pressure and at the regeneration temperature. Note in this case the resulting load shall be considered to act in conjunction with 115% of the adsorbent bed weight (weight of bed with design levels of water and CO2 adsorbed). If not specified otherwise, the bed density shall be assumed to be 865 kg/m3 (54.0 lb/ft3). Case 1 will govern the required thickness of the bed support plate, number and size of support beams, support ledge thickness, and similar items. Case 2—Upwards loading: 0.172 bar (2.5 psi) pressure drop across the bed support plate in the upwards direction with the vessel at feed operating pressure and temperature. Note the resulting uplift on the bed support system shall be considered to act alone (no benefit of adsorbent bed weight to be included, as it is assumed that the bed has been fluidized). Case 2 will govern the number of bed support plate fixing clips required (Figure 6), cover plate thickness, and the quantity and size of cover plate bolting, size, and number of bed support beam holding down bolts.
6.2.1.2 See paragraph 6.4 for the appropriate stress limits for the two load cases. The plate design shall consider the effect of the holes made for the nozzle screens (by the use of a ligament efficiency).
6.2.2 Allowance for Future Re-rating Plant: In some plants, the installed bed height may later be increased. For standard designs, the design of the bed support plate and its structure should be based on the maximum expected product bed height the vessel can accommodate rather than the installed bed height. The PES will specify the adsorbent loading to be used for the design of the bed support plate.
6.2.3 Bed Support Plate Thickness: The plate thickness will depend on the loading and the position of supports. The plate shall be a minimum of 12 mm thick for vertical vessels, a minimum of 15 mm thick for horizontal vessels, and a maximum of 33 mm thick. For thicknesses greater than 33 mm, Air Products approval is required, since the threaded length of the standard nozzle screens has to be increased. If necessary the vessel supplier may choose to machine the perimeter of the bed support plate to meet the flatness tolerances of this specification. In this case the supplier shall include a suitable machining allowance.
6.2.4 Corrosion Allowance (internals): Internal attachments shall have a corrosion allowance of 1.5 mm minimum on each surface (that is, a 3 mm minimum total on thickness). This means that: The bed support plate will have a 3 mm (total) allowance on thickness. The top surface contacts the alumina and is expected to be wet during each reactivation. The lower surface is impacted by the wet inlet air during the adsorption phase. For vertical vessels the props, and bed support skirt ring that connect the bed support plate to the bottom head and the doubler plates on the bottom head also have 3 mm corrosion allowance on thickness unless conditions are unusually severe (advised in the PES). For horizontal vessels, the stiffeners and support beams under the plates should be sized to give 6 mm corrosion allowance on total thickness. If the support beams are hot dipped galvanised then the corrosion allowance may be reduced to 3 mm on total thickness.
6.3 Design of Bed Support Structure: The loading that is acting on the bed support plate must be carried by the edge support ledge and any other support structure as follows.
6.3.1 Vertical Vessels
6.3.1.1 Position of Bed Support Skirt—Smaller diameter vessels (under 2500 mm inside diameter) can be designed with the plate supported only at the edge support ring. Larger vessels will need extra support to keep the plate thickness down to 25 mm. The position of the bed support skirt is critical to the maximum stress level in the bed support plate. Determination of the skirt position requires a finite element analysis. This will be performed by Air Products and the skirt position shown on the vessel setting plan. The bottom head will deflect under the local loads from the props, but sensitivity studies have shown that the load carried by the skirt and props does not change significantly with this deflection, and it can be neglected.
6.3.1.2 The bed support ledge welded to the vessel wall shall be at least 25 mm thick. The actual support ledge thickness and number of gussets shall be selected by the vessel vendor to minimize fabrication distortion and achieve the required flatness tolerance. If necessary the vessel supplier may choose to machine the bed support ledge to meet the flatness tolerances of this specification. In this case the supplier shall include a suitable machining allowance in the ledge thickness. Machining the bed support ledges (and underside of the bed support plates) is recommended.
6.3.1.3 Vertical Vessels – Design of Props: The loading in the props that support the bed support skirt is axial compression, and the stress shall be limited to the allowable values from a structural code. The bottom end of each prop is welded to a doubler pad on the inside of the bottom head. The stress at the doubler pads can be evaluated using normal pressure vessel methods such as PD5500 Annex G or WRC107, with allowables taken from the applicable vessel code. The vessel internal operating pressure and temperature should be taken as acting when the local loads in the bottom head are assessed. Unless specified otherwise the support props and bed support skirt will be designed and specified by Air Products.
6.3.1.4 The shell longitudinal seam in the vicinity of the rope seal and rope seal retaining plate shall be ground flush on the inside of the vessel.
6.3.2 Horizontal Vessels
6.3.2.1 The bed support plates are usually supported additionally on structural beams running across the vessel. The bed support plate load is taken to be uniformly distributed around the four edges of the plate. The bed support plates may require stiffening, with bed support plate stiffeners, in this case the clearance between the ends of these stiffeners and the flanges of support beams or the edges of the bed support ledge shall not be less than 10 mm (see Figure 17).
6.3.2.2 The bed support beams are bolted to their support brackets and are permitted to expand by the slotted bolt holes (orientated along the beam axis). To prevent the beams moving along the longitudinal axis of the vessel, stops are fitted to the support brackets and bed support ledge (see Figures 11A and 11B). The top flange of the bed support beams shall not be ‘notched’ to give clearance for nozzle screens.
6.3.2.3 The bed support plate and edge seal arrangement may be ‘faceted’ or curved to match the head profile at vessel vendor’s choice. See Figure 16.
6.3.2.4 The support beams shall be designed to limit their maximum bending stress to 2/3 the material yield at the regeneration temperature during load case 1 of paragraph 6.2.1.
6.3.2.5 The support brackets holding the ends of the beams will induce local stress in the vessel shell that shall be limited to code allowables, taking the vessel internal pressure to be the adsorption phase design pressure and the temperature to be the regeneration/bake out temperature. Unless specified otherwise the vessel supplier is responsible for these calculations. All bed support brackets shall be attached to the shell via reinforcing pads. These reinforcing pads shall not overlap main shell circumferential or longitudinal weld seams.
6.3.2.6 The support beam bolting shall be designed to carry the uplift forces produced by load case 2 of paragraph 6.2.1.
6.3.2.7 The bolted joints in the bed support plates (see Figures 6A and 6B) shall be located over bed support beams. The minimum bolt spacing and bolt size shall be determined by calculation, but shall not be less than required by paragraph 6.1.7, nor exceed the maximum pitch specified in Note 5 of Figure 6B. The bolt load shall be calculated on the basis that when the screen thermally expands, it ‘sticks’ at what should be its ‘free’ end hence, all the frictional load at the sliding end is carried by the bolts, until screen frees itself and moves. A coefficient of friction between the screen plate and support beam of 0.30 shall be assumed to evaluate the frictional load on the bolted joint. The bolts should be checked for fatigue under this cyclic bolt load, using a minimum SCF of 4.0 for the threads.
6.3.2.8 Unless specified in the PES otherwise the bed support plates, plate joints, support beams, and brackets will be designed and specified by Air Products.
6.3.2.9 The dimensions and tolerances of the support beams are critical to the bed support system and maintenance of required clearances; hence beam dimensions may not be changed without Air Products approval. Where standard beam sections of the required dimensions are not available, the support beams shall be fabricated from plate. Fabricated beams shall have continuous connecting welds and shall have their top and bottom flanges machined flat.
6.3.2.10 Horizontal vessels shall be supplied with permanent clips/brackets installed inside the vessels to enable ‘runway’ beams to be installed for installing and moving the bed support screen plates.
6.3.2.11 All longitudinal weld seams in horizontal vessels shall be located above the absorbent bed level (that is, accessible without removing the absorbent).
6.3.3 Bed Support Plate Anchors and Motion Limit Stops
6.3.3.1 Each bed support plate shall be ‘anchored’ at or near its geometric centre. In horizontal vessels this will be at the midpoint of the support plate bolted joint to a support beam (see Figure 6A). In larger vertical vessels the anchoring will be provided by the support skirt and props. In smaller vertical vessels the bed support plates need not be anchored. These anchors must also be designed to carry the uplift forces produced by load case 2 of paragraph 6.2.1.
6.3.3.2 Motion limit stops shall be fitted to the peripheral underside of all screen sections. Minimum three per side on support plates of horizontal vessels Minimum one per meter circumference of vertical vessels
6.3.3.3 The motion stops shall be fitted after the screen is installed and centralized. Unless specified otherwise, the clearance on the limit stop shall be set at 3 mm. The 3 mm clearance is suitable for use with screens with a maximum linear dimension (width, length, or diameter) not exceeding 4850 mm.
6.3.3.4 The 3 mm clearance gaps shall not be fitted with packers for shipping/transport – the intent is that the vessel should be ready for operation when delivered, without the need to enter the vessel to remove shipping packers.
6.3.4 Rope Seal Retaining/Cover Plates
6.3.4.1 The rope seal cover plate may be made in sections, joints shall be wrapped in stainless steel shim material as shown in Figures 8 and 13. Joints in cover plates of vertical vessels shall have bolted connections as shown in Figure 13.
6.3.4.2 The rope seal cover plate bolting spacing shall not exceed 300 mm. The cover plate bolting shall be designed to carry its share of the uplift forces produced by load case 2 of paragraph 6.2.1. This may require cover plate bolting spacing closer than the maximum.
6.3.4.3 The cover plate should be held in place by the clamp screws (vertical vessels) or nuts (horizontal vessels), but it is important that the screws/nuts are only lightly tightened. The cover plates shall not grip the edges of the bed support plates and restrict their movement. The screws/nuts must not be used to correct waviness or irregularities in the cover plate.
Note: On horizontal vessels, a tab washer is required to prevent the studs working loose (see Figure 8).
6.4 Stress Limits—The maximum stress in the support beams and the bed support plate shall be limited to the yield stress of the plate material at the appropriate temperature. Stress in bolting shall be limited to Code allowables.
6.4.1 Attachments to Vessel—Ledges, pads, clips, and similar items that are welded to the vessel pressure parts and that carry the loading from the bed support plate, will be subject to cyclic loading. This loading comes from the reversal of the pressure drop through the bed when the TSA changes from feed to reactivation, and from the cyclic stress in the pressure vessel shell. The feed and reactivation bed pressure drops will be as paragraph 6.2.1 unless stated otherwise in the PES. Responsibility for fatigue design is defined in paragraph 15.2.
6.5 Deflection Limits—For both vertical and horizontal vessels, the maximum vertical deflection of the support plate should be limited to the larger of 3 mm or 1/500 of the span. A check should also be made on the rotation of the plate to edge bar joint. The maximum lift of the plate from the support ledge or the maximum opening of the packed seal width should be limited to 1 mm.
6.5.1 The deflection of support beams in horizontal vessels shall be limited to larger of 3 mm or 1/500 of the span.
7. FLOATING SCREENS
7.1 See PES for requirement and 4WEQ-1070.
8. GAS SAMPLING PROBES
8.1 See PES for requirement and 4WEQ-1070.
9. INTERNAL FILTER
9.1 See 4WEQ-1070
10. ADSORBENTS
10.1 The adsorbent material will be installed at site by others.
11. CLEANING
11.1 See 4WEQ-1070.
12. PAINTING OF EXTERNAL SURFACES
12.1 See PES for requirement, 4WEQ-1070, and 4WEQ-6804.
13. INSPECTION AND QUALITY PLAN
13.1 The following inspection activities will be performed by the Air Products inspector during the visits noted in the QCP. See 4WEQ-1070 for inspection activities that are common to all types of TSA vessels. See DOC0000657799 for inspection activities that are specific to TSA vessels. Check that the bed support plate is flat and level. Check that any welds in the bed support plate are of good quality and are ground flush on both surfaces where they could interfere with the proper fit of a nozzle screen or sliding of the plate on its supports. Check that the correct number of nozzle screen mounting holes have been made, and that the distribution complies with the approved design drawing. Check that the seal edge bars on the support plate are of the correct height and that the top surface is flat and level. Check the overall dimensions of the bed support plate. Check that the support ledge(s) on the vessel wall is (are) at the correct elevation and that they are flat and level. Check the seal gap below the edge of each bed support plate – the maximum gap between the ledge on the vessel and the bottom of the bed support plate is 1.5 mm. This maximum gap is critical and gaps greater than 1.5 mm will need to be corrected. The entire perimeter of each bed support plate shall be surveyed and any area(s) exceeding a 1.5 mm gap shall be reported to Air Products. Check the width of the seal (the gap into which the fibre-glass rope is fitted) – any variation greater than on the design drawing shall be reported to Air Products. Check that the bed support plate is in the correct position – centered so that the variation in seal width is minimized. For horizontal vessels, check that the seal plates (stainless steel shims to cover the gap between the ends of the support beam and the vessel bracket) are in place and secure. Check that the movement limit stops and anchors (only on horizontal vessels) on the underside of the bed support plate are in place and the clearances are per the approved design drawing. After the seal cover plates are assembled, check the gap between the top of the support plate seal edge and the cover plate. Check that the cover plate is not ‘clamping’ the edge of the screen. For vertical vessels, the radial gap between the outside of the seal cover plate sections and the inside of the vessel shall be checked. The maximum gap is 3 mm and larger gaps should be corrected. After the nozzle screens have been installed, each one shall be checked to ensure that it has not been over tightened. It should be possible to rotate the screen by hand, but it should not be possible to rock the screen such that there is a measurable gap between the screen and the support plate. The locking tack weld between the round nut and the threaded tail piece of each nozzle shall be inspected. The weld must be sound, without excessive spatter, undercut, or overfill.
13.2 All inspection measurements associated with the bed support installation shall be recorded and provided to Air Products for review.
14. LIFTING AND TRANSPORT
14.1 See 4WEQ-1070 and 4WEQ-1010.
15. CALCULATIONS
15.1 Bed Support System
15.1.1 Calculations shall be provided to cover the following: Total bed weight (weight of adsorbent) for the design case. Downwards Uniformly Distributed Load (UDL) on bed support plate and effective uniform load/unit screen plate perimeter. Upwards Uniformly Distributed Load (UDL) on bed support plate and effective uniform load/unit screen plate perimeter. Calculation of stress and maximum deflection in bed plate in corroded condition. Rotation of edge of bed support plate. Loading on bed plate support system and hold down (that is, ledge, beam, skirt, and cover plates). Stresses in bed plate support and hold down system including weld sizing and bolting. Stresses in vessel caused by loads from bed plate supports.
15.2 Pressure Parts
15.2.1 See 4WEQ-1070. If the supplier is performing the fatigue design of the vessel, the cyclic effects on the bed attachments of the reversing pressure drop through the bed must be included.
16. INFORMATION TO BE SUPPLIED WITH THE BID
16.1 See 4WEQ-1070.
16.2 Additional information to be provided: The thickness of the bed support plate Break out price for installing the nozzle screens Break out price for prime painting the vessel (instead of finish painting)
Figure 1 Installation of Nozzle Screen (Typical Horizontal and Vertical Vessels)
Notes: Nozzle screens will be supplied free issue by Air Products and be fitted by the vessel fabricator. The PES or setting plan will indicate the nozzle screen tail pipe diameter.
| Nozzle Screen Tail Pipe Diameter | Required Support plate hole diameter (D) |
| 1″ BSP (33.25 mm O/D) | 38 |
| 1 ¼” BSP (41.91mm O/D) | 47 |
Split washers shall be fitted above and below the bed support plate. Hand tighten nut – do not use wrench. When correctly fitted it should be possible to slide the nozzle screen from side-to-side in the bed support plate, but it should not be possible to lift the nozzle screen relative to the bed support plate. When correctly tightened, tack weld nut to threads. Dimension ‘X’ shall be as follows;
| Location on Screen | Required Support plate hole to edge spacing (X) |
| All rope packed joints | 85 |
| Bolted joint over bed support beams | 120 |
Figure 2 Basic Details of Rope Packed Joint (Vertical Vessel)
Notes: To achieve required rope gap tolerance, the vessel shell must be made to a tight out-of-roundness tolerance at the support ring location and bed support OD must be made to suit actual shell ID. The limit stops must be fitted after the bed support plate has been installed and centralized in the vessel. The maximum gap shall be checked using a 1.5 mm NO-GO gauge. Rope packing (number of layers per paragraph 6.1.5) shall be installed in the shops (after hydrotest), by the vessel fabricator. Grind vessel longitudinal weld seam flush on the inside of the vessel at the location of the rope seal and cover plate. On assembly there shall be at least 5 mm of overlap between the rope cover plate and the inside edge of the bed support plate side wall.
Figure 3 Basic Details of Rope Packed Joint (Horizontal Vessel)
(See Figure 14 for alternative details)
Notes: To achieve required rope gap tolerance, the bed support plate dimensions must be made to suit actual inside seal face dimensions measured in the vessel. Any vessel welds crossed by the support ledges, gussets, or retaining ring shall be free from embedded and surface defects. NDE by RT/UT and MT/DP is required before attaching the supports. Support ledge and retaining plate parts shall be shaped to fit the contour of the vessel dished heads. The support ledge thickness may be increased and/or the number of support gussets increased by the vessel vendor to achieve the specified flatness tolerances. Gusset spacing shall not exceed 375 mm; the vendor may add more as required in order to maintain the flatness of the support ledge. However, there shall be at least one centered on each support beam. In the dished head there shall be a gusset aligned with each stiffener on the bed support plates. The retaining plate ring ‘bolting’ shown above, shall be studding (with nut and lock nut) or hex head cap screws, screwed into tapped holes, so that it can be changed out in service if necessary; ‘inverted’ bolts that cannot be subsequently replaced from above shall not be used. To prevent the bolting loosening during operation, s.stl tab washers are required (see Figure 8). ‘*’ depends on vessel geometry – fabricator to adjust these dimensions to satisfy all other specified dimensions. The 1.0 mm flatness tolerance on the top surfaces of the support ledge and the retaining plate ring are for reference only. Air Products’ experience is that these items must be fabricated to be flat and in-plane. However, the 1.0 mm tolerance is not a process levelness requirement, the overriding process requirement is the control of the gaps between the bed support plate and the support ledge and the rope cover plate. Therefore, some deviation from this 1.0 mm levelness tolerance over the length of the vessel is permitted, if the stated ‘gap’ tolerances are met (Note: In practice this will mean the support ledge must be flat and in-plane for the length of each bed support screen assembly, but it does not necessarily have to be level within 1.0 mm over the entire length of the vessel).
Figure 4 Approved Details for Bed Support Plate Edge (Horizontal and Vertical Vessels)
Notes: The top edge of the side plate and underside of the bed support plate outer edge shall be machined to achieve the required flatness and tolerance on the support plate edge height. For Vertical vessels the outside ‘diameter’ of the support plate edge may require machining if the vessel fabricator cannot achieve the necessary roundness and diameter control (necessary to achieve the rope gap width tolerance) by fabrication methods alone. This is a ‘reference’ dimension. The fabricator may need to alter this dimension to suit the as-machined dimension of the rope packing wall plate (see Figure 3) to achieve required gap dimension under rope packing retaining plate (0.5 mm gap minimum and 1.5 mm Max gap, refer to Figure 8).
Figure 5 Approved Details of Support Beam Rope Packed Joint (Horizontal Vessel)
Notes: On assembly there shall be at least 5 mm of overlap between the rope cover plate and the inside edge of the bed support plate side wall. Movement limit stops to be fitted (using a 3 mm spacer) after screen plate has been installed and rope packing gaps equalized by vessel fabricator. See paragraph 6.3.3.2 for spacing and number of limit stops. The gap between the bed support plate and bed support beam shall be checked using a 1.5 mm NO-GO gauge. Movement limit stop gaps shall be checked using a 3 mm GO/NO-GO gauge. Rope packing (number of layers per 6.1.5) shall be installed in the shops (after hydrotest) by the vessel fabricator. There shall be a spacer washer fitted to the cover plate stud or a ‘U’ shim fitted over the in-fill plate top edge to achieve the required clearance between the cover plate and bed support plate side wall. The cover plate nuts must be done up tight, hence spacer washers or shims must be used as required between cover plate and in-fill plate.
Figure 6 A Approved Details of Support Plate Fixed Joint (Horizontal Vessel)
Alternative detail;
Notes: Bed support plate fixing clips to be fitted after screen plate has been installed, the rope packing gaps equalized by vessel fabricator and after making the fixed joint between the bed support plates. Purpose of fixing clips is to lock support plate to beam vertically (that is, no lift possible) and axially (support plate cannot slide relative to beam). See paragraph 6.3.3.1 for spacing and number of fixing clips. See Figure 6B for details of the bolted joint and capping channel. To assist adjustment of the perimeter rope gap on assembly, it is acceptable to include in the design of the bed support plates a full depth shim strip (up to 12 mm wide). This shim strip can be reduced in width as necessary to improve/equalise the rope gaps above beams or in the vessel heads.
Figure 6B Approved Details of Support Plate Bolted Joint (Horizontal Vessel)
Notes: The bolted joint shall be trial assembled to check for gaps between flanges and fit of capping channels BEFORE final assembly using ‘RTV’. Gap measurements shall be recorded and reported to Air Products for acceptance. Capping channel sections to be fabricated from stainless steel material (0.4-0.6 mm) to fit over the bolted flange connections between screen plates. At joints between capping channels, the channel toes shall be notched back to achieve a web overlap as shown. A bead of RTV should be run along the top of the bolted join (in the ‘notch’ provided) before final fitting the capping channels. The joining bolts shall be located on pitch of not more than 200 mm (8 in), typically the bolting shall be located at the same pitch as the nozzle screens and be located mid-way between them. Support plate joint bolting shall be ‘hard’ tightened with a hand wrench, before tack welding of the nut to the bolt thread. Any gaps between capping channels and the screen plate flanges shall be sealed with RTV. Bolting shall comply with 4WEQ-1070. The ends of the capping channels shall be notched as shown so that they extend under the rope cover plates and the ends are folded down into the rope gap.
Figure 7 Approved Details of Rope Packing Corner Joint (Horizontal Vessel)
Notes: Shim plate thickness to be 0.4-0.6 mm.
Figure 8 Details of Rope Packing Retaining Plates (Horizontal Vessel)
Notes: A type ‘A’ bed support plate is shown above, this detail is typical for all bed support edge detail types and both support ledge alternatives (Figures 3 or 14). The limit stops must be fitted after the bed support plate has been installed and centralized in the vessel. The limit stops may be increased in size if necessary to provide access for welding. Minimum weld required is 50 mm down each side and 50 mm across end of stop. The maximum gap shall be checked using a 1.5 mm NO-GO gauge. Rope packing (number of layers per 6.1.5) shall be installed in the shops (after hydrotest) by the vessel supplier. The rope packing retaining plate shall entirely cover the glass rope packing. The rope packing retaining plates shall not have any welded joints. Joints in the rope packing retaining plates shall be sealed using stainless steel shim material (approximately 0.4-0.6 mm thick) placed under the retaining plates at all gaps and fitted per details shown. On assembly there shall be at least 5 mm of overlap between the rope cover plate and the inside edge of the bed support plate side wall.
Figure 9 Details of Support Beam Studding (Horizontal Vessel)
Notes: Studding shall be austenitic stainless steel.
Figure 10 Details of Support Plate Lifting Lugs (Horizontal and Vertical Vessels)
Notes: Lifting lug to suit 1/2″ ‘Green Pin’ bolt type anchor shackle in accordance with Federal Specification RR-C-271D, pin diameter =12.7 mm, SWL = 2 tons.
Figure 11A Detail of Support Beams and Support Brackets (Horizontal Vessels)
Notes: Beam holding down bolts (M16 or 5/8″ UNC minimum, stainless steel) shall be hand tightened and the threads tack welded. The beams must be free to thermally expand and contract relative to the vessel. Nominal 10 mm gap under beam to be checked on assembly and shimmed with full area, stainless steel shim plate to maintain top surface of beam level with bed support plate. Shim to be welded to support bracket. Fit beam flange guide blocks on assembly (thickness to suit). Purpose is to fix beam’s position axially in the vessel. Fit beam upper web guide blocks on assembly (see Figure 11B). Purpose is to fix beam’s position axially in the vessel. Beam web gussets to be full width of upper and lower flanges (taper gussets if upper flange width less than lower). H = 500 mm minimum; if this cannot be achieved please discuss with Air Products ( H=410 mm is the absolute minimum permitted by agreement with Air Products).
Figure 11B Detail of Support Beam Upper Web Guide Blocks (Horizontal Vessels)
Notes: Fit beam upper web guide blocks on assembly. Purpose is to fix beam’s position axially in the vessel. Guide blocks shall be positioned so as to clear the beam web/flange corner radius or fillet weld, alternatively the guide blocks shall be chamfered to clear the corner radius or fillet weld.
Figure 12 Detail of Bed Support Skirt and Legs (Vertical Vessels)
Notes: Legs are made of pipe and shall have a minimum of 3 mm (total corrosion allowance) and be at least Schedule 80 wall thickness. The pipe ends shall be slotted top and bottom to suit the support clips and support ring. The slots shall be made over long to provide some length adjustment on assembly. Refer to vessel setting plan for skirt diameter and number and NB of legs. A reinforcing pad shall be provided under the leg support clip.
Figure 13 Detail of Cover Plate Joint Details (Vertical Vessels)
Notes: The purpose of the bolting is to push ring segments against vessel wall and minimize any gap between the wall and ring. Joints in the rope packing retaining plates shall be sealed using stainless steel shim material (approximately 0.4-0.6 mm thick) placed under the retaining plates at all gaps and fitted per details shown.
Figure 14 Alternative Arrangement for Bed Support Ledge (Horizontal Vessel) (alternative to Figure 3)
Notes: To achieve required rope gap tolerance, the bed support plate dimensions must be made to suit actual inside seal face dimensions measured in the vessel. The support angle thickness may be increased and/or the number of support gussets increased by the vessel vendor to achieve the specified flatness tolerances. Gusset spacing shall not exceed 375 mm. However, there shall be at least one gusset centered on each support beam. In the dished head there shall be a gusset aligned with each stiffener on the bed support plates. Support angle and retaining angle parts shall be shaped to fit the contour of the vessel dished heads. Any vessel welds crossed by the support angles, gussets or retaining angle shall be free from embedded and surface defects. NDE by RT/UT and MT/DP is required before attaching the supports. Stop the lower angle attachment weld either side of 10 mm drain notches, to permit hydrotest water to drain out. Thicknesses are minimum after machining. The 1.0 mm flatness tolerance on the top surfaces of the support ledge and the rope packing retaining angle are for reference only. Air Products’ experience is that these items must be fabricated to be flat and in-plane. However, the 1.0 mm tolerance is not a process requirement; the overriding process requirement is the control of the gaps between the bed support plate and the support ledge and the rope cover plate. Therefore, some deviation from this 1.0 mm levelness tolerance over the length or width of the vessel is permitted, if the stated ‘gap’ tolerances are met.
Figure 15 Final Inspection (Horizontal and Vertical Vessels)
See notes on next page.
Figure 15 (continued) Final Inspection (Horizontal and Vertical Vessels)
Notes: Materials: i) NO-GO gauge = 25 wide x 1.5 thick metal strip (if it fits in gap, joint needs rectification). ii) RTV = high temperature silicon sealant (see 6.1.6 for specification and approved grades) iii) 3 mm Gauge = 25 x 2.95 thick bar. Inspection: a) Check gap under bed support plate using NO-GO gauge (from below the bed support plate). b) Gap(s) under rope packing retaining plate to be checked using NO-GO gauge (from above the bed support plate) with retaining bolts loose or under a small load. c) Movement limit stop clearance shall be checked using a 3 mm gauge. d) Check overlap of coverplate complies with this specification. Final assembly: Remove rope seal retaining plates, RTV in positions shown (if required – see Note 4), install rope packing. Replace retaining plates, fitting shim covers at plate joints. Tighten rope seal retaining plates bolts under small load (finger tight + ½ turn) and lock, rope seal retaining plates should not be gripping bed support plates and impede their thermal expansion. For horizontal vessels, this may require shim washers to be fitted under the retaining plates. The seal retaining plate bolting shall not be used to correct flatness/waviness of the retaining plate. If satisfactory clearances cannot be achieved without excessive load being applied, the retaining plates shall be re-worked. RTV sealant shall be applied where gaps exceed the stated tolerances, however Air Products approval is required to seal gaps >1.5 mm. Approval might not be given if gaps are excessive or extensive.
Figure 16 Alternative Details for Bed Support Plate in Dished Ends of Horizontal Vessels
Figure 17 Clearance Gap Between Support Beam and Screen Plate Stiffener (Horizontal and Vertical Vessels)
Notes: The purpose of the 10mm (Minimum) clearance between the Bed Stiffener Plate and Support Beam is to ensure that there is no conflict between the two during thermal expansion. (See Figure 6 and 6A for detail of thermal expansion limit stops.)
Figure 18 Nozzle screen protection grating (Horizontal and Vertical Vessels)
Notes: A grating as shown above shall be installed under each The above figure is conceptual only, the supplier is responsible for the detail design. The grating may be made of any commercially avialable platform grating that statisfies this specification. The grating shall be galvanised. The grating shall comprise of 2 sections, attached by stainless steel bolting, so that each section is removable through the vessel manway(s). Each section shall be designed to support a 100kg point load. Each section shall be approximately 450x1000mm for DN500 manways and 500x1000mm for DN600 manways. The grating shall be supported by ‘legs’ welded to the bed support plate, such that the underside of the grating is 25-50mm above the top of the nozzle screens.
Appendix A Sample Calculation for Required Quantity of Rope Packing
