Specifications for EA31002 U Tube Bundle for CDU 3

Transcription

1 Specifications for EA31002 U Tube Bundle for CDU 3 Tube Bundle Specificatio Tube Bundle for Heat Exchanger EA31002A/B/C/D Quantity required : One with Dummy shell Exchanger Type: BEU Horizontal No of U Tubes : 234 Tube Sizes: 32mm OD x 2.77 mm THK x 3750mmLG. 32mm OD x 2.50 mm THK x 3750mmLG Tube Material: SA210 Gr.A1 Seamless Stationary tube sheet material/dimension : SA 266 Gr.2 Tube to tube sheet joint :Heavy expansion Design Code: ASME SEC V111 DIV.1 (Latest) and TEMA R (Latest) Drawing Number: H-1250/FAD/2010- Sheet 1, 2 & 3 Inspection : Stage wise Inspection by Third Parties Like LRIS/EIL/BVIS/TOYO/DNV/TUV/IRS 1. Review of Quality Assurance Plan (QAP), approval by MRPL 2. Review of Test certificate for traceability of material meeting original specification as per the drawing. 3. If the material is sourced from vendor other than manufacturer, then selection of samples (min two samples from each heat/lot) for mechanical and chemical (product analysis) test. All mechanical test required as per applicable material specification shall be witnessed by TPI. 4. Witness of UT scanning. 5. Witness of Impact test of forgings carried out as per ASTM A-388 and acceptance criteria shall be as per of Section VIII Division II. 6. Review of ECT of tubes & Witness Hydrotest of tubes (100%). 7. Review of Mock up test for tube to tube sheet joint. 8. Stage wise inspection during fabrication. 9. Witness Tube sheet inspection after drilling and skeleton assembly before tube insertion. 10. Inspect percentage thinning, Length of Expansion etc. of Tube to tube sheet joint. 11. Review of Heat Treatment report of forged parts as per specification.

2 12. Witness pneumatic test of Tube to Tube sheet joints. 13. Witness of the hydrotesting of the tube bundle. 14. Review calibration reports of measuring instruments. 15. Inspection for dimensional conformance and marking. 16. Issue Product release note giving details of inspection carried out. Hydrostatic test and other tests 1. These tests shall be witnessed by MRPL / MRPL authrised inspectors or Third party inspectors at vendor s shop. Hydrostatic test shall be performed with indicating pressure gauge connected to the uppermost part of the equipment. Water used for these tests shall be salt free. Minimum metal temperature during hydrotest shall be 20º C. and the test pressure shall be maintained for a duration of minimum one hour period. 2. Final hydrotest shall be carried out to Kg/cm2g on the shell side. Required Dummy shell /Test Rings/Test Flanges/Test Covers shall be designed & Manufactured by the vendor for the purpose of Hydro testing of the Tube Bundle at the vendor s shop. Notes : Tubing Specification:(REF SPEC No.00-ES Rev-1) 1. All Tubing shall be seamless & cold drawn. 2. Tube gauge / thick specified is the required minimum wall thickness unless otherwise specified. 3. Tubing shall be in the fully heat treated conditions as received from the mill. Heat treatment shall be annealed for CS & SS tube. 4. Product analysis of tubes shall be carried out & reported. Material test certificate to be submitted along with the Tube Bundle. 1. Tubes and tube bundles a) The ratio of outer diameter to length of removable tube bundles shall be limited so that the bundle is sufficiently stiff for maintenance and hoisting. b) Rolled tubes shall project 3 ± 0.5 mm beyond the tube-side face of the tube sheet of horizontal exchangers. For vertical exchangers, the tubes shall flush with the tube-side face of the top tube sheet to allow complete drainage. c) Tube to tube sheet joint expanded with two grooves without welding d) Tube holes in the tubesheets shall be drilled as per TEMA-Special close fit. For metric tube of size 32mm OD, the nominal size of holes shall be 32.27mm with tolerance ± 0.07 mm. Holes in tubesheets shall be drilled and reamed to final size. Holes shall have no burrs or scoring marks and shall be circular with parallel sides and normal to the tubesheet surface. Edges of the hole shall be deburred.

3 2. Tube Expander & Expanding of Tubes. a) Tube expander used by the fabricator shall be electronically controlled type and shall be in good condition and shall have the inspector s approval. The tube expander shall have stops to prevent the rollers approaching nearer 3mm to the back of the tube plate. b) Tubes shall be expanded into the tubesheet by using the equipment and setting as previously agreed between the inspector and fabricator. Such settings may be required to be proved by procedural testing, or at the discretion of the inspector, fabrictor s established settings may be used. C) Tubes shall be expanded for the full thickness of the tube plates less the 3mm at the back-side-of face of the tube sheet. However, for tubesheet thickness more than 5 x Tube OD, expansion may be limited to 4 x Tube OD on the front side and 1x tube OD on the back side of the tubesheet. Care shall be taken to avoid any distortion of the tubesheet or gross deformation of the ligaments. It is suggested that tubes expanded systematically in small, diametrically opposite groups. 4. Pressure Testing a) After expansion of all tube joints in exchanger is completed, tube sheet face and the internal surfaces of the tubes to a length of about 15mm shall be thoroughly cleaned. Any grease or oil shall be suitably removed by the use of proper solvent or by steam jet. These joints shall then be subjected to pneumatic air-soap solution test of 1.25 Kg/cm 2 g. Leaking tubes shall be further expanded in the presence of inspector after reasons for the leakage have been ascertained and accepted by the inspector. If excessive thinning (>15%) is required to check the leakage, same shall be reported to MRPL before such expansion is carried out. b) Expansion joints shall also be subjected to hydrostatic leakage test at a test pressure indicated in the drawing. Leakage if any, shall be reported to MRPL. However leakage tubes leaking tubes if any may be further expanded keeping the guidelines given above in view. c) Water for hydrostatic testing, shall have appx. 25 (By volume) of an approved wetting agent in addition to 0.2% of sodium nitrate as corrosion inhibitor. Draining and drying requirements shall be as per spec. 4. Positive means of ensuring alignment and prevention of misassembly shall be provided for the following: Floating head cover, channel cover having grooved partitions, stationary tube sheet and shell flange. 5. No distortion whatsoever shall be permitted on the gasket seating surfaces, If distorted the same shall be machined. 6. Sliding strips shall be provided to facilitate pulling the removable tube bundles. Sliding strips shall be properly seated in the baffles, secured with a complete seal weld (both sides) and attached to the stationary tube sheet with a full penetration weld. The sliding strips shall protrude 2mm beyond the periphery of the baffles. Vertical exchangers shall be provided with four sliding strips evenly divided around the circumference of the bundle. When mechanical cleaning is required on shell side

4 (square-pitch patterns), the sliding strips shall not obstruct the tube lanes or pass partition. 7. Baffles shall be tied together with rods and spacers and provided when necessary with 90 top and bottom notches 10 mm wide for venting and draining. The drainage notches shall be increased to 25 mm width in case shell side fluid is exceptionally dirty or contains slurry. 8. The use of a 2-pass shell employing a continuous longitudinal baffle shall require buyer's approval. 9. If necessary, impingement protection shall be provided either by a square-plate or round- plate baffle, two rows of impingement rods and a distributing belt or by an enlarged inlet nozzle with an internal-distributor plate. 10. Impingement baffle shall be as per VS-42. If special baffle is specified, the following criteria shall be applied. 11. Plate baffles shall extend at least 25 mm beyond the projection of the nozzle bore. 12. The unrestricted bundle entrance flow area at the impingement plate baffle shall not be less than the flow area of the inlet nozzle. Materials 1. Materials shall conform to the specifications tabulated in the TEMA standards. All materials subjects to internal or external pressure shall also conform to the specification given in ASME, section VIII, division The material of internals such as baffles, tie rods, etc., Refer attached Material Specification sheet 3. Reinforcement pads shall be made of the same material as the shell, channel or head. Design codes with latest editions The latest design codes given below shall be used for design, manufacture, testing and acceptance of the equipment. i. ASME Boiler and Pressure Vessel code Sec. VIII div. I ii. TEMA, standard of tubular exchanger manufacturers association ( class as specified on the drawings / Data sheets) iii. ASTM specification iv. AWS -ASME specification for welding electrodes v. ANSI (American national standard institute ) B 16.5 steel pipe flanges and flanged fitting and B16.11 Forged fittings socket welding & threaded. vi. IBR (whenever applicable)- Indian Boiler Regulation

5 vii. EJMA (Expansion joint manufacturers association standard. Design and Drawings approvals 1. The drawing & Material of Construction Sheet issued with this enquiry is for estimation purpose only. 2. The manufacturer shall prepare detailed fabrication drawings and material of construction and it shall be submitted for approval. Procurement of materials, fabrications etc shall start only after such approval. Guarantee. The manufacturer shall be responsible for any defects due to any inferior materials or workmanship developed under operating conditions within 12months from the date of the commissioning or 18months from the date of receipt of the equipment at the site whichever is earlier. and the manufacture shall attend his own cost & make necessary repairs and /or replacements without delay.