NAVY MIL-STD-796 A-1988 CHEMICAL CLEANING OF MAIN AND AUXILIARY BOILERS (HYDROCHLORIC ACID METHOD)《主辅锅炉的化学清洁(氯化氢酸化法)》.pdf

1、 MIL-STD-77bA LJLJ a 77797LL 0033782 3 M L LIT ARY STAN DARD CHEMICAL CLEANING OF MAIN AND AUXILIARY ROILERS (HYDROCHLORIC ACID METHOD) I INCH-POUND 1 MXL-STD-796A( SH) 16 March 1988 SUPERSEDING bl I L-STD- 7 9 6 ( SHIPS ) 3 January 1966 (See 6.3) AMSC NIA FSC 4410 DISTRIBUTION STATEMENT A Approved

2、for publlc release; dlutrlbutlon unimlted THIS DOCUMENT CONTAINS / ( p PAGES. Licensed by Information Handling ServicesI MIL-STD-77bA 44 m 7777733 O033783 5 m MIL-STD-7 96A( SH) 16 March 1988 DEPARTMENT OF JXE NAVY NAVAL SEA SYSTEMS COMMAND Washington, DC 20362-5101 Chemical Cleaning of Hain and Aux

3、iliary Boilers 1. This Military Standard is approved for use by the Nnval Soa Syatome Command, Department of the Navy, and is available for uac by nJ1 Daportntr and Agencie8 of the Department of Defense. 2. Beneficial comments (recommendations, additions, daieton8) 8nd any perri- nent data which may

4、 be of use in improving this documant ahould bd addrodred to: Commander, Naval Sea Systems Command, SEA 5523, Dapnrtwnt of tho Navy, Washington, DC 20362-5101 by using the seif-addreeead Stendordiretion bcuaonr Improvement Proposal (DD Form 1426) appenring at thc end of chla docuwni or by letterr Li

5、censed by Information Handling ServicesMIL-STD-77bA LlLl W 0033984 7 W MIL-STD-796A(SH) 16 March 1988 Paragraph 1 . 1.1 1.2 2 . 2.1 2.1.1 2.1.2 2.2 2.3 3 . 4 . 4.1 4.1.1 4.1.2 4.1.3 5 . 5.1 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 5.2.5.1 5.2.6 5.2.7 5.2.8 5.2.10 5.2.11 5.3 5.3.1 5.3.2 5.3.3 5.3.4 5.3.5 5.

6、4 5.4.1 5.4.1.1 5.4.1.2 5.4.1.3 5.2.9 CONTE NT S Page SCOPE . Scope Procedure REFERENCED DOCUMENTS Government documents . Specifications . Other Government publications Other publications . Order of precedence DEFINITIONS . (Not applicable) GENERAL REQUIREMENTS General requirements . Application Uti

7、lities Removal of preservative or oil . DETAILED REQUIREMENTS . Mobile cleaning equipment Preparation of boiler and equipment (see figure 1) . Ventilation Tube removal . Desuperheater cleaning . Steam separators and girth plates Superheater and economizer blanking Superheater and economizer cleaning

8、 Valves. gauges. manholes. handholes and gaskets . Steam drum connections . Temporary valve manifold . Hydrostatic teet . Boiler preheating Boiler draining Chemicals required . Boiling out solution . Mild acid solution . Nitrogen Specific cleaning procedure Descalant preparation and injection Descal

9、ant temperature Descalant soaking and recirculation Descalant testing Descalant solution . Passivating solution . 2 3 3 4 5 5 5 5 5 5 5 6 6 6 7 7 7 7 7 7 ? Licensed by Information Handling ServicesMIL-STD-79bA 44 W 49979LL 0033985 7 W Paragraph 5.4.1.4 5.4.1.5 5.4.2 5.4.3 5.4.4 5.4.4.1 5.4.5 5.5 5.5

10、.1 5.5.1.1 5.5.2 5.5.3 5.5.4 5.5.5 5.5.6 5.6 5 . h . 1 5.6.2 5.6.2.1 5.6.2.2 5.6.2.3 5.6.3 5.6.4 5.6.5 5.6.6 5.6.7 5.6.8 5.6.9 5.6.11 5.6.12 5.7 5.6.10 Y i g u re 6 . 6.1 6.2 6.3 1 MIL-STD-796A(SH) 16 March 1988 CONTENTS . Continued Page Records Descalant dralning . Vater rinse. Mild acid rinse Pass

11、ivating solution preparation . Passivating solution injection and draining Opening and ventilating Inspection Crimping . Water jetting Reinstallation . Hydrostatic test . Boiler fill and light off Blowdown . Safety precautions . Safety coordination Ventilation Hydrogen venting . Nitrogen venting . H

12、ydrogen chl,pr. ide venting Acid spillage Personal protective equipment Safety shower and eyewash Boiler lfght off . Equipment location . Shlps pumps . Acld dilution Acid circulation . Superheater leakage Passivato and acid Disposal regulations . Procedure following chemical cleaning 7 8 8 8 8 8 8 9

13、 9 9 9 9 9 9 9 9 9 9 10 10 10 10 10 10 10 10 10 10 10 10 11 11 NOTES . Il intended use . It Subject term (key word) listing 11 Changes from previous issue 11 FICURE Plping diagram . 12 iy . o Licensed by Information Handling ServicesMIL-STD-77bA 44 m 77777LL 003378b O m HI L-STD-7 96A( SH; 16 March

14、1988 1. SCOPE 1.1 Scope. This standard covers the requirements governing the procedure or chemical cleaning of main boilers of ferrous alloy construction and iiixlliary boilers of ferrous alloy or silicon-bronze alloy (Iierculoy) construction. NAVSEA approval shall be obtained prior to acid cleaning

15、 any boiler. 1.2 Procedure. This procedure is intended for use under the direction of a chemist and is not intended or use by chips force due to the hazardous nature of the chemicals employed. The procedure described hereln shall not be used for cleaning superheaters or other sections of stainless s

16、teel construction nor shall it be used for cleaning desuperheaters or other sections o 16 percent chromium - 1 percent nickel construction. 2. 2. 2. cations REFEKENCED DOCUNENTS Government documents. .1 Specifications. Unless otherwise specified, the following specifi- of the issue listed in that is

17、sue of the Department of Defense Index of Specifications and Standards (DoDISS) specified in the solicitation forin u part of this standard to the extent specifled herein. SPECIFICATIONS FEDER AL 0-H-765 - Hydrochloric Acid, Technical. O-S-5 7 1 - Sodium Carbonate, Anhydrous, Technical O-S-604 - Sod

18、ium Metasilicate, Technical. O-S-6 39 - Sodium Phosphate, Dibasic, Anhydrous, Technical, O-S-642 - Sodium Phosphate, Tribasic, Anhydrous; BB-N-4 1 1 - Nitrogen, Technical. Dodecahydrate; and Monohydrate; Technical. MILITARY MIL-S-13727 - Sodium Phosphate, Monobasic, Anhydrous, Technical. MIL-D-16791

19、 - Detergents, General Purpose (Liqud, Nonionic). MIL-1-17433 - Inhibitor, Hydrochloric Acid Descaling and MIL-R-19180 - Regulators, Pressure, Compressed Gas. DOD-P-23236 - Paint Coating Systems, Steel Ship Tank, Fuel and MIL-P-24138 - Passivator Compound, Navy Boiler. MIL-P-24441 - Paint, Epoxy - P

20、olyamide, General Specification foc. NIL-11-29210 - Hose Assembly, Rubber, Metal Lined, Wire Reinforced, Pickling Solutions. Salt Water Ballast. (Metric) 250 psig, Saturated and Superheated Steam Service. 2.1.2 Other Government publications. The olLowing other Government publications form a part of

21、this standard to the extent Specified herein. 1 Licensed by Information Handling ServicesMIL-STD-77b 44 = 77779LL 0033787 2 W MIL-STD-796A(SH) 16 March 1988 PU B L ZC AT I ON S NAVAL SEA SYSTEMS COMMAND (NAVSEA) NAVSEA S9086-CY-STM-OOO/CH-221 - Naval Ships Technical Manual, NAVSEA S9086-CX-STM-020/C

22、H-220 V2 - Naval Ships Technical Manual, Boilers . Boiler Water/Feedwater Test . and Treatment. NAVSEA 0951-LP-037-5010 - High Pressure Water Jet Cleaning Equipment. (Copies of specifications and publications required by contractors in connection with specific acquisition functions should be obtaine

23、d from the contracting activity or as directed by the contracting officer.) 2.2 Other publications. The following document forms a part of this standard to the extent specified herein. Unless otherwise specified, the issues of the documonts which are DoD adopted shall be those listed in the issue of

24、 the DoDISS specified in the solicitation. Unless otherwise specified, the issues of documents not listed in the DoDISS shall be the issue of the nongovernment documents which is current on the date of the solicitation. AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) 2358.1 - American National Standard

25、 or Emergency Eyewash and Shower Equipment. (DoD adopted) (Application for copies should be addressed to the American National Standards Institute, 1430 Broadway, New York, NY 10018.) (Nongovernment standards and other publications are normally available from the organizations which prepare or which

26、 distribute the documents. These documents also may be available in or through libraries or other informational services.) 2.3 Order of precedence. In the event of a conflict between the text of this standard and the references cited herein, the text of this standard shall take precedence. 3. DEFINI

27、TIONS Not applicable. 4. GENERAL REQUIREMENTS 4.1 General requirements. I 4.1.1 App lication. This procedure shall be applied for removal of mill scale from new boilers prior to final acceptance trials as well as for removal of waterside deposits which can form in boilers after extensive operation.

28、4.1.2 Utilities. The following utilities needed for chemical cleaning are normally av.ailable at dockside for use by shipynrd personnel or prvate contractors fulfilling Naval contracts at Naval shipyards: L 2 (3 Licensed by Information Handling ServicesL MIL-STD-79bA L14 m 99797LL 0033988 m MIL-STD-

29、7 96A( SH ) 16 March 1988 (a) Fresh water. (b) Distilled, feed or tap water containing less than 50 (c) (d) (e) Electrical power. parts per million (p/m) hardness as calcium carbonntc. Steam at 100 pounds per square inch (lb/in*). Compressed air at 90 to 100 lb/in2. 4.1.3 Removal of preservative or

30、oil. If visual inspcctlon of bollcr vator- sides reveals the presence of preservative or oil, the boiler shall bc bollcd our prior to acid cleaning in accordance with NAVSEA S9086-CY-STH-OOO/C-ZZl. Tho boiling out solution shall be as specified in 5.3.1. Tha bollng out rolutlon shall be heated by lo

31、w pressure steam and maintained nt 50 to 100 lblln2 for a minimum of 24 continuous hours. The vente shall be cracked to provido for intermittent steam injection into the solution. After dumping of tho bolllng out solution, the boiler watersides shall be thoroughly rnrcd ulth fooduator meeting the re

32、quirements specified in NAVCEA S9086-CX-CTH-OZO/Cil-22 V?. 5. DETAILED KEQUIREMENTS 5.1 Mobile cleaning equipment. The contractor or ihlpyard rhrll havo the following trailer or truck mounted equipment: TWO acid tanks with a minimum capacity of 3000 gallona rotai. Two acid pumps each with a minimum

33、capacity of 100 gltllonr One proportioning header or Ita aquivalent for blonJlng acld, One steam heater assembly for h8Ating roiutiona. Five hundred feet of 1.5 inch acid hone rAtod at 150 lb/ln Assorted hoses for air, nitrogen or water rupply and for Flexible metallic rteam houe meatlng tho raqulra

34、mntr rpocttted One chemical tcet klt for dctcralnlng acld conconrrotlon df One cxplorimetar (Hlncs Safety Appllancar, Hodel 1 or One portable pyrometer (Alnor Pyrocon or oqulvrlant) And Aeeorted nonsparking toolr lncluding hanmera, wronchor, acre*- Safety clothing to be vorn by operarlng crw ond oth

35、or rafoty per minute against 50-foot head. water and steam. for admitting solutionr to the boiler. venting hydrogen from chc boilor. in MIL-11-29210, solut ione. equivalent ). assorted thermowtarr. driverr and toolr to repair acid ciarnlng oqulpnr. provirionr ir required (roe 5.6). 5.2 Preparation o

36、f boiler and equlpwnt (roo flguro Ir, 5.2.1 Ventilation. The boiler rhrll be vantllarod in accordanca uth 5.6.2 before any pereonncl are illowad to entor. 5.2.2 Tube removal. A rcrccn row tubo, not racontly lnrtallod, mtiali IC removed from each boiler to be cloanod, praforably from an atoa abour oi

37、o-haif to two-thirds of furnace dupth. Tho tubos rhrrll k rcplncod or (ho holai sttdll 3 Licensed by Information Handling ServicesMIL-STD-77bA q4 7777731 0033787 b H MZL-STD-796A(SH) 16 March 1988 c be plugged. The tube shall be spltt and retained for record purposes to dcmoii- strate the original c

38、ondition o the boiler. A tube from a new boiler shall only be removed for the inspection of 5.5.1. To determine cleaning effectiveness, a tube from a new boiler may be removed prior to acid cleaning and securely hung 111 H vertical position in the steam drum, 5.2.3 otherwise undesirable phosphates m

39、ay precipitate on the cleaned boiler surfaces. 5.4.4.1 Passivating solution injection and draining. The passivating solution shall be introduced into the boiler and economizer, if it was cleaned, at 150 to 160“F, circulated for 10 minutes and held for an additional 30 minutes at 150 to 160F. The pas

40、sivating solution shall be displaced by iiitrogeii or sir. 5.4.5 Opening and ventilating. The boiler shall be opened immediately after dumping, ventilated in accordance with 5.6.2 and inspected in accordance with 5.5.1. An explosimeter shall b used around the boiler and in the steam drum to ascertai

41、n the absence of explosive gas before proceeding with the Lnspection. Oxygen sufficiency shall be checked before entering the boiler. P o Licensed by Information Handling ServicesMIL-STD-77bA 4Li 9777711 0033774 T M MIL-STD-796A(SH) 16 March 1988 5.5 Procedure following chemical cleaning. 5.5.1 Insp

42、ection. The boiler shall be ventilated in accordance with 5.6.2 before any personnel are allowed to enter. the cleaning operation, a screen tube shall be removed, preferably adjacent to the tube removed prior to acid cleaning. The tube shall be split and then thoroughly wire brushed to remove loose

43、deposits. A tube from new boilers, if not removed prior to acid cleaning as specified in 5.2.2, shall be removed and inspected. To determine the effectiveness of I 5.5.1.1 Crimping. A split tube section (from an area that was located in a bend near the water drum) shall be crimped in a vise. If hard

44、 crimpable deposits are found on the tube, the boiler shall be recleaned following the procedure specified herein. A few small particles or fine granules do not constitute hard, crimpable deposits. 5.5.2 Water jetting. Fullowing the successful acid cleaning operation, all boiler waterside surfaces s

45、hall be cleaned using a high pressure water jet in accordance with NAVSEA S9086-GY-STM-OOO/CH-221 and NAVSEA 0951-LP-037-5010, Water jetting may be delayed if work is to be performed on the boiler. After water jet cleaning is completed, the boiler shall be dried out, preferably by using hot air. 5.5

46、.3 Reinstallation. Temporary connections shall be removed and fittings reinstalled. that have been in contact with acid shall be renewd. Blanks shall be removed and all boiler parts which were removed prior to acid cleaning shall be rein- s talled. Manhole and handhole gaskets and any valve gaskets

47、or packing 5.5.4 Hydrostatic test. After reinstallation of all boiler parts, a hydrostatic test shall be applied to the boiler and bottom blow system in accordance with NAVSEA S9086-GY-STM-OOO/CH-221, After the hydrostatic test is performed, the water used for the hydrostatic test shall be drained f

48、rom the boiler. 5.5.5 Boiler fill and light off. Prior to light-off, the boiler shall be filled with feedwater and chemically treated in accordance with NAVSEA S9086-GX-STM-020/CH-220 V2. it shall be brought up to operating temperature slowly. When the boiler is fiist lit off after cleaning, 5.5.6 B

49、lowdown. After the boiler is lit off, it shall be blown down frequently until the boiler water is clear. 5.6 Safety precautions. 5.6.1 Safety coordination. The ontractor or shipyard representative shall ensure that the cleaning work is coordinated through the safety superin- tendent to provide personnel protection from acid and other chemical hazards. 5.6.2 Ventilation. The oxygen content in the boiler shall be meanured by a calibrated instrument and shall be between 20 and 22 percent by volume before any personnel are allowed to enter the boiler. All nitroge