機械畢業(yè)設計外文翻譯---紙漿和造紙行業(yè)中的無水氨壓力容器

1、<p><b>　　附錄一 外文原稿：</b></p><p>　　Anhydrous Ammonia Pressure Vessels In The Pulp And Paper Industry</p><p>　　The purpose of this article is to ensure that pulp and paper operating

2、 companies, their engineering consultants, and inspection contractors are informed about stress corrosion cracking in anhydrous ammonia service. The information was written by a task group of the TAPPI Engineering Divisi

3、on Nondestructive Testing and Quality Control Subcommittee.</p><p>　　Bacteria in some activated sludge effluent treatment systems require supplementary food. In some cases, this food is provided by ammonia a

4、nd phosphoric acid which are stored on the mill site. Ammonia is commonly stored as anhydrous liquid ammonia in carbon steel vessels at ambient temperature and 16 bar (250 psig) pressure.</p><p>　　These vess

5、els can be subject to stress corrosion cracking (SCC).SCC could cause release of ammonia, which is a hazardous chemical. SCC of carbon steel vessels in anhydrous ammonia service is somewhat analogous to that experienced

6、in continuous digesters. For example, the importances of stress relief during fabrication and of in-service inspection are common to both.</p><p>　　This article concerns storage in horizontal pressure vessel

7、s at ambient temperature, as this type of vessel is used in pulp and paper applications. Large refrigerated storage tanks are used for atmospheric pressure storage in the chemical industry.</p><p>　　History

8、of Scc In Ammonia Storage Vessels</p><p>　　The history of SCC in carbon steel ammonia storage vessels was reviewed by Loginow (1) and is also briefly summarized in a NACE Technical Committee Report entitled

9、“Integrity of Equipment in Anhydrous Ammonia Storage and Handling” (2). In the 1950s, liquefied ammonia began to be injected directly into soil for fertilization. Failure of carbon steel storage vessels by SCC began to o

10、ccur. These failures were unexpected since liquefied ammonia had been used for many years in the refrigeration, chem</p><p>　　Investigation confirmed SCC to be the cause of cracking. Three recommendations we

11、re made in 1962 that still form the basis of modern codes:</p><p>　　? Pressure vessels should be fully stress relieved.</p><p>　　? Extreme care should be used to eliminate oxygen from ammoni

12、a systems.</p><p>　　? Ammonia should contain at least 0.2% water to inhibit SCC.</p><p>　　Loginow reported that adoption of these recommendations practically eliminated SCC in carbon steel ves

13、sels in the agriculture industry. However, in a recent Western Canadian survey SCC was found in 100 of 117 field storage vessels inspected by wet fluorescent magnetic particle testing (WFMT) (3).</p><p>　　De

14、spite the above measures SCC continued to occur in road transport tanks constructed from high strength steels, in refrigerated storage vessels and in vessels which had been weld repaired but not subsequently stress relie

15、ved. An additional recommendation to limit steel tensile or yield strength was embodied in the U.S. and British ammonia storage codes, respectively (4, 5).</p><p>　　? ANSI K61.1—Nominal tensile no greater

16、than 70,000 psi (580 MPa)</p><p>　　? U.K. Code—Minimum specified yield strength shall not exceed 350 MPa (51,000 psi).</p><p>　　PRACTICAL CONSIDERATIONS</p><p>　　This article is c

17、oncerned mainly with practical considerations important to pulp and paper mills already possessing anhydrous ammonia storage vessels or planning to fabricate such vessels. In view of the industry’s experience with SCC in

18、 continuous digesters the governing objectives should be to control fabrication and inspection to prevent, or at least minimize, in-service problems including over-reaction to relatively minor crack indications. Guidance

19、 is available in the published codes and de</p><p>　　Fabrication</p><p>　　The two main objectives in fabrication should be to provide the most crack resistant vessel possible at reasonable cost

20、and to ensure that an adequate inspection baseline is available for interpretation of subsequent in-service inspections.</p><p>　　ASME Section VIII Division 1 does not require stress relief for anhydrous amm

21、onia storage pressure vessels unless the owner specifies a lethal service designation.</p><p>　　The lethal service designation requires radiographic testing (RT) of all butt welded joints plus post weld heat

22、 treatment.</p><p>　　ANSI K-61.1-1989, “American National Standard Safety Requirements for the Storage and Handling of Anhydrous Ammonia,” adds several requirements:</p><p>　　? Fabrication to AS

23、ME Section VIII Division 1 Table UW 12 at a joint efficiency less than 80% is not allowed.</p><p>　　? Inspection and testing under UG-90(c) (2) (multiple, duplicate pressure vessel fabrication) is not allowe

24、d.</p><p>　　? Steel used for pressure containing parts shall have a nominal tensile strength no greater than 580MPa (70,000 psi).</p><p>　　? The minimum design pressure for ambient temperature s

25、torage shall be 16 bar (250 psig).</p><p>　　? Post weld heat treatment is mandatory and a furnace of sufficient size to accommodate the entire vessel is recommended. Welded attachments may be made to pads af

26、ter post weld heat treatment.</p><p>　　? Horizontal vessels shall be mounted on saddles which extend over at least one third of the shell’s circumference. Thermal expansion and contraction shall be allowed f

27、or and means provided to prevent corrosion between the shell and the saddles.</p><p>　　The 1986 British Code “Storage of Anhydrous Ammonia under Pressure in the United Kingdom” requires:</p><p>

28、　　? Steel must have specified minimum yield strength less than 350 MPa (51,000 psi).</p><p>　　? Weld filler must have minimal strength overmatch compared with the base plate.</p><p>　　? 100% mag

29、netic particle inspection of all internal welds in order to provide a record against which all future inspections of the vessel can be assessed.</p><p>　　? No welding is permitted after stress relief without

30、 subsequent local stress relief.</p><p>　　? Concrete saddles are prohibited.</p><p>　　? Support must be on continuously welded steel saddles attached before stress relief.</p><p>　　

31、Although the British Code does not state that magneti particle inspection should be by WFMT it is generally agreed that WFMT is the most sensitive technique and should be used for inspection of ammonia storage vessels. A

32、ll inspection should be performed by qualified technicians. SNT-TC-1A Level II is a recommended minimum.</p><p>　　One pulp and paper company has added the following requirements for fabrication of such vesse

33、ls:</p><p>　　? Incorporation of a “corrosion allowance” of at least 1.6 mm (1/16 in.) to permit minor defect chasing during in-service inspections and to provide a margin against pitting which may occur if w

34、ater is allowed to enter an out of service vessel.</p><p>　　? All weld toes profiled by grinding prior to wet fluorescent magnetic particle testing (WFMT). All WFMT indications greater than 1.6 mm (1/16 in.)

35、 to be removed by grinding before post weld heat treatment.</p><p>　　? Shear wave ultrasonic testing (UT) of nozzle-to-shell welds permitted if RT is judged impractical.</p><p>　　? WFMT to be re

36、peated after final hydrotest test of the vessel and the report retained by the owner.</p><p>　　? Vessel to be dried completely after hydrotest test and nitrogen padded until filled with ammonia.</p>&

37、lt;p>　　Valves, piping, and fittings</p><p>　　Both the ANSI and U.K. codes address piping, valves, and fittings. A detailed summary is beyond the scope of this article, but some points are worth noting.<

38、;/p><p>　　? ANSI K61.1 requires all nonrefrigerated ammonia piping to meet the requirements of ANSI/ASME B31.3 “Chemical Plant and Petroleum Refinery Piping.”</p><p>　　? The U.K. Code states copper

39、 and copper bearing alloys shall not be used.</p><p>　　ANSI/ASME B31.3 requires a minimum of 5% of piping welds be radiographically tested. Valves and other apparatus should be rated for ammonia service and

40、should not contain copper or copper alloy components.</p><p>　　In one case, a nickel rupture disc corroded to failure at its periphery due to formation of an ammonia solution at a gasketed joint exposed to t

41、he weather.</p><p>　　In-service inspection</p><p>　　Vessel entry Liquid or gaseous ammonia is hazardous and in some jurisdictions release of ammonia vapor to the atmosphere is prohibited by la

42、w. Vessels must be properly purged by water and/or steam. Detailed procedures for vessel purging and entry are available from ammonia suppliers (6).</p><p>　　Inspection procedures The ANSI standard does no

43、t address in-service inspection but does state weld repair or alteration must conform to the current edition of the National Board Inspection Code (NBIC).</p><p>　　The 1992 edition of the NBIC includes nonma

44、ndatory guidelines for inspection of liquid ammonia vessels (7).</p><p>　　These guidelines recommend:</p><p>　　? Power buffing or light sandblasting as surface preparation for inspection</p&g

45、t;<p>　　? All interior welds be examined by WFMT.</p><p>　　? Cracks should be removed by grinding without encroaching on the minimum thickness required by ASME Section VIII and the original design.<

46、;/p><p>　　? Weld repairs, regardless of size, should be post weld heat treated wherever possible.</p><p>　　Light grinding does increase the sensitivity of WFMT compared to sandblasting or power buf

47、fing (8). For example the NBIC mandates grinding as surface preparation for deaerator inspection. The omission of grinding in the guidelines for ammonia vessel in-service inspection may be due to concern that rough grind

48、ing may produce residual stress sufficient to initiate SCC in anhydrous ammonia service. If welds have been properly profiled for WFMT on initial fabrication, then grinding for in-service in</p><p>　　The NBI

49、C guidelines also state that other inspection methods such as acoustic emission or ultrasonics may be used and that fracture mechanics may be used to assess the integrity of vessels where complete removal of cracks is no

50、t practical.</p><p>　　Normally the only corrosion that occurs in anhydrous ammonia vessels is due to water ingress during out of service periods. Shallow pitting, however, has been found in the bottom of som

51、e vessels beneath oily deposits. The source of oil is presumed to be from compressors used to handle the ammonia.</p><p>　　In view of concerns over air contamination due to vessel entry and residual stress i

52、mparted by grinding nonintrusive inspection, techniques like acoustic emission and UT could be considered by vessel owners. The British Code does not mention nonintrusive inspection of ambient temperature pressure vessel

53、s but does state that, if acoustic emission is to be used for spherical storage vessels, a reference base should be taken during initial hydrotesting. Nonintrusive inspection is being used in othe</p><p>　　V

54、essel refilling Safety procedures should be established for refilling a vessel that has been emptied for inspection. It is also very important to purge the vessel of air to prevent the occurrence of SCC. Detailed instr

55、uctions are available from ammonia suppliers (10). If a vessel is not to be returned to service immediately after inspection, then care should be taken to dry it and possibly nitrogen-pad it depending on the time it will

56、 remain out of service.</p><p>　　Inspection frequency Neither the ANSI document nor the NBIC deals with inspection frequency. The British Code recommends the following:</p><p>　　? WFMT inspectio

57、n of 100% of all internal butt welds within the first three years of service</p><p>　　? WFMT re-inspection within 2 years if significant defects are found</p><p>　　? Subsequent to no significant

58、 defects being found, any subsequent inspection should include WFMT of all Tee junctions and 10% of the total length of butt welds</p><p>　　? In no case should the subsequent examination interval exceed 6 ye

59、ars.</p><p>　　It is apparent from the above that latitude can exist for in-service inspection techniques and frequencies. Each owner should determine inspection frequency in conjunction with the appropriate

60、authority. Some jurisdictions require a 3-year inspection frequency.</p><p><b>　　SUMMARY</b></p><p>　　The use of carbon steel pressure vessels for storage of anhydrous ammonia in the

61、 pulp and paper industry could be a non-event or deteriorate into a cycle of inspection and repair. This article has highlighted major concerns related to SCC. There is a wealth of additional information available on all

62、 considerations related to these vessels from the ANSI and British Codes, the NACE document, ammonia suppliers, and the current technical literature. The American Institute of Chemical Engineers (AICh</p><p>

63、;　　Reid is materials and corrosion section head with MacMillan Bloedel Research, 4225 Kincaid St., Burnaby, BC, Canada V5G 4P5.</p><p>　　Task group members: Craig Reid; R.S. Charlton, Levelton Associates Con

64、sulting Engrs.; R.C. Faloon, MQSInspections Inc.; and W. E. Boudreau, Belle Testing Inc.</p><p>　　Literature cited</p><p>　　1. Loginow,A.W. , Materials Performance 25 (12): 18(1986). &

65、lt;/p><p>　　2. NACE Technical Committee report 5A192, Integrity of Equipment in Anhydrous Ammonia Storage and Handling, Houston, NACE Storage Tank, Spokane, 1992.</p><p>　　3. Stephens, J. D. and

66、Vidalin, F., 1994 AIChE Ammonia Symposium Notes, American Institute of Chemical Engineers, New York, p. 9. </p><p>　　4. Compressed Gas Association Inc., American National Standard Safety Requirements for

67、the Storage and Handling of Anhydrous Ammonia ANSI K61.1-1989, Arlington, VA, 1989 (CGA Pamphlet G-2.1-1989).</p><p>　　5. Storage of Anhydrous Ammonia Under Pressure in the United Kingdom, London, H

68、er Majesty’s Stationery Office, 1986. (Health and Safety Booklet HS/G 30)</p><p>　　6. Cominco Fertilizers (U.S.) Inc., Decommissioning an Ammonia Storage Tank, Spokane, 1992.</p><p>　　7. The

69、National Board of Boiler and Pressure Vessel Inspectors, National Board Inspection Code: A Manual for Boiler and Pressure Vessel Inspectors, Columbus, OH, 1992, p.197.</p><p>　　8. Reid, J. C. and Reid, C.,

70、TAPPI 1992 Engineering Conference Proceedings, TAPPI PRESS, Atlanta, Book I, p.163.</p><p>　　9. Conley, M. J., Sture, A., and Williams, D., “Ammonia Vessel Integrity Program: A Modern Approach, 1990 AIChE A

71、mmonia Symposium Notes, New York, AIChE, 1990.</p><p>　　10. Cominco Fertilizers (U.S.) Inc., “Commissioning an Ammonia Storage Tank”, Spokane, 1992.</p><p><b>　　附錄二 外文翻譯：</b></p&

72、gt;<p>　　紙漿和造紙行業(yè)中的無水氨壓力容器</p><p>　　本文的目的是為了確保紙漿和紙張經營公司，他們的工程顧問，承建商了解在脫水氨設備中的應力腐蝕開裂現象。這篇資料是由美國紙漿與造紙工業(yè)技術協(xié)會無損檢測工程部和質量控制小組委員會共同編寫。</p><p>　　細菌生存在一些活性污泥污水處理系統(tǒng)中需要充足的食物。在某些情況下，這種食品是氨和磷酸的儲存現場。氨通常

73、以無水液氨的形式貯存在室溫和1.6MPa（250 磅）的壓力的碳鋼容器中。</p><p>　　這些容器可能會受到應力腐蝕開裂（SCC）。應力腐蝕開裂可能導致氨泄露，這是一種危險化學品。用于無水氨設備的碳鋼容器中的SCC是有點類似于連續(xù)蒸煮罐的經驗。例如，減少壓力的引入在生產和在役檢查過程都是很常見的。本文關注在常溫下的臥式壓力容器，像這類型容器通常用于紙漿和造紙的應用。大型冷藏儲罐在化工行業(yè)一般是常壓儲存。&l

74、t;/p><p>　　SCC在氨儲罐的歷史</p><p>　　SCC在碳鋼氨儲存容器的歷史是由Loginow（1）審查通過,也是在簡要回顧了NACE技術委員會報告題為“完整的設備在無水氨的儲存和處理”(2)。在20世紀50年代，液氨作為肥料直接注入土壤。碳鋼貯存容器由于應力腐蝕開裂而導致的故障開始出現。這些故障是意外，因為液氨已用于在制冷，化工多年，金屬??熱處理行業(yè)沒有報告的問題。

75、 調查結果證應力腐蝕是開裂的原因。1962年提出了三條建議構成了現代條例的基礎： ?壓力容器應充分消除應力。 ?要特別小心是消除氨系統(tǒng)中的氧氣。 ?氨應該包含至少0.2％的水，以抑制應力腐蝕開裂。Loginow報告說，采用這些建議能有效避免應力腐蝕發(fā)生在農業(yè)用碳鋼容器中。然而，最近的加拿大西部的調查顯示通過濕熒光磁粉探傷檢查（WFMT）（3）發(fā)現117處農場的儲罐中有100處發(fā)生了應力腐蝕開裂。 盡管采

76、用了上述措施，SCC仍然發(fā)生在由高強度鋼建造的公路運輸油罐、冷藏儲存容器以及作了焊接修復卻沒后續(xù)的應力消除的容器。另外一條建議被納入美國和英國的氨儲存條例，以限制鋼材的拉伸或屈服強度。 ?ANSI K61.1 -名義抗拉強</p><p>　　從上述可以很明顯看出在役檢查技術和頻率存在一定范圍。每個使用者應與結合相關部門確定檢查頻率。有些管轄區(qū)需要3年的檢查頻率?？偨Y對紙漿和造紙工業(yè)的碳鋼無水氨儲存壓力

77、容器的使用可能是一個非活動或進入檢查和維修的惡性循環(huán)。本文重點關注的是應力腐蝕開裂。從ANSI和英國規(guī)范，NACE文件，氨儲罐供應商和現行的技術文獻可以獲取的大量有關注意事項的信息。在美國化學工程師學會（AIChE）舉行的年度合成氨安全研討會旨在發(fā)現在安全生產，運輸和儲存氨及相關化學品的方法。這些專題討論的會議記錄AIChE公開發(fā)表。它建議任何此類容器的所有人應及時了解當前的專業(yè)知識。</p><p>　　里德材

78、料和麥克米蘭布勒德爾研究，4225金凱德街，本拿比，BC，加拿大V5G 4P5腐蝕科科長。工作組成員：克雷格里德; R.S.查爾頓Levelton協(xié)會咨詢工程部。R.C. Faloon鋼筋混凝土s公司和W. E. Boudreau檢測公司參考文獻：[1] Loginow，A.W. ，材料性能25（12）：18（1986）。[2] NACE的技術委員會的報告5A192，無水氨儲存和處理設備的完整性，休斯敦，NACE的儲罐，

79、斯波坎，1992年。[3] 斯蒂芬斯，JD和Vidalin，F，1994年AIChE氨研討會報告，美國化學工程師協(xié)會，紐約，P，9。[4] 壓縮氣體協(xié)會公司，貯存及無水氨的ANSI K61.1 - 1989，阿靈頓，弗吉尼亞州，1989年處理的美國國家標準的安全要求（CGA手冊的G - 2.1 - 1989）。[5] 無水氨在英國倫敦常壓下的儲存，英國政府文書局，1986。 （健康及安全手冊協(xié)/克30）[6] Comin