臺灣博碩士論文加值系統

鍋爐透過適度的預防保養工作，可以減少其失效的次數，但適當的預防保養間隔及計畫範圍卻難以決定。過於頻繁地執行預防保養工作，可能會降低鍋爐的可用率，取而代之的保養概念為預知保養或診斷保養。根據統計，爐管之失效絕大部份是因金屬異常高溫所引起，管內結垢則是主要原因，每次停爐的損失至少在數百萬元以上，對於爐管髒污的程度，目前電廠維修人員係採用一種破壞性的方法，於每間隔兩年之機組歲修停爐時，由現場切取樣管檢測結垢物的厚度，然而，取樣點常受限於環境，取樣作業困難，有些尚必須搭建工作架始能工作，既費時又多花錢，因而有減少取樣點與取樣頻率的趨勢。此外，檢測的過程亦容易受到人為污染影響而失去代表性，也由於其是一種間接的檢測方式，較不具時效性。
本研究係採用一種非破壞性的檢測方法，即在爐管管壁埋設嵌入式熱電偶，稱之為儀用爐管，以連續監測爐管之金屬溫度變化，進而以統計的方法研判管內髒污的程度，藉由趨勢管理找到最佳的保養間隔，適時提供量化的維護決策依據。主要的研究內容包括：
1.以安全的角度建構鍋爐預知保養(化學清洗時機)機制，找出保養的間隔時間。
2.以可靠度的角度建構爐管預知更換(高溫潛變殘餘壽命評估)模式，找出更換的間隔時間。
3.以單位時間維護成本最小化模式評估鍋爐預防維護(預防保養與預防更換)策略，即以成本最小化的角度找出保養與更換的間隔時間。

Although preventive maintenance, when it is appropriate, can reduce the frequency of failures, it is often difficult to determine the proper maintenance interval and scope of a preventive maintenance program. Preventive maintenance action performed too frequently may actually decrease availability. An alternative proactive maintenance concept is predictive or diagnostic maintenance. According to failure statistics of boiler tubes, they almost are due to abnormal metal temperature caused by internal scaling, the losses of boiler does not work is at least NT$ millions for each time. The method currently used for checking internal dirt in boiler tubes involves destructive testing. This method is subject to certain limitations caused by the difficulty of taking test-samples. The points to be monitored are often positioned in such a way that improvised scaffolds have to be provided, making the taking of test-samples a long and costly process. Because of this, there is a tendency to reduce both the number of the points where test-samples are take below the figure required under the relevant specifications as well as the frequency of testing. In addition, checking of the dirt level is carried out by indirectly, this can be affected by human, which have less timely and representative to making a decision on maintenance.
This research describes a non-destructive method of monitoring internal dirt using thermocouples of insert type installed in the tubes wall, called instrumented tubes, which can monitor continuously a variety of metal temperature, in aid of assessing the dirt level in the tubes by the method of statistic and analysis, by means of trend management to find the interval time of maintenance, offering quantitative maintenance decision in time. This research consists of following items：
1.From the angle of safety of boiler to construct a mechanism of predictive maintenance (chemical cleaning time) and to find the interval time of maintenance.
2.From the angle of reliability of boiler to construct a model of predictive replacement (to estimate the remaining creep life of boiler tubes) and to find the interval time of replacement.
3.From the angle of minimal maintenance cost per unit time to evaluate the policy of preventive maintenance and to find the interval time of maintenance with replacement.

目錄 頁次
摘要-------------------------------------------------------------------------------- i
Abstract----------------------------------------------------------------------------i i
誌謝--------------------------------------------------------------------------------iv
目錄-------------------------------------------------------------------------------- v
圖目錄---------------------------------------------------------------------------viii
表目錄-----------------------------------------------------------------------------x
符號說明-------------------------------------------------------------------------xi
第一章 緒論------------------------------------------------------------------- 1
1.1研究背景與動機------------------------------------------------ 3
1.2研究目的--------------------------------------------------------10
1.3研究範圍-------------------------------------------------------- 11
1.4研究架構-------------------------------------------------------- 12
第二章 文獻探討------------------------------------------------------------ 17
2.1預知維護-------------------------------------------------------- 18
2.2可靠度理論----------------------------------------------------- 20
2.3預防維護策略-------------------------------------------------- 21
2.3.1固定間隔維護策略------------------------------------- 21
2.3.2預定壽命維護策略------------------------------------- 25
2.4定期維護作業規劃-------------------------------------------- 27
2.5非定期維護作業規劃----------------------------------------- 28
2.6維護對可靠度的影響分析----------------------------------- 29
2.6.1可靠度退化分析---------------------------------------- 29
2.6.2維護對可靠度的影響---------------------------------- 31
第三章 建構鍋爐預知保養機制------------------------------------------ 32
3.1問題點陳述----------------------------------------------------- 32
3.2研究方法-------------------------------------------------------- 34
3.2.1儀用爐管之操作原理---------------------------------- 34
3.2.2收集數據及其應用------------------------------------- 38
3.3範例與資料分析----------------------------------------------- 41
3.3.1單因子實驗---------------------------------------------- 41
3.3.2變異數分析---------------------------------------------- 41
3.3.3模型適當性檢查---------------------------------------- 42
3.3.4樣本大小之決定---------------------------------------- 43
3.3.5簡單線性迴歸分析------------------------------------- 44
3.3.6估計H值------------------------------------------------- 44
3.3.7趨勢管理------------------------------------------------- 45
第四章 建構爐管預知更換模式------------------------------------------ 50
4.1問題點陳述----------------------------------------------------- 51
4.2爐管潛變殘餘壽命預測之方法論-------------------------- 52
4.2.1時間溫度參數法---------------------------------------- 53
4.2.1壽命消耗分數法則------------------------------------- 53
4.3爐管預知更換模式之建構----------------------------------- 54
4.3.1模式設計之基本假設---------------------------------- 55
4.3.2評估爐管高溫潛變殘餘壽命之步驟與方法------- 55
4.3.3潛變壽命消耗分數------------------------------------- 59
4.3.3建立殘餘壽命遞減趨勢------------------------------- 60
4.4範例與資料分析----------------------------------------------- 60
4.4.1高溫潛變壽命評估------------------------------------- 60
4.4.2結果說明------------------------------------------------- 61
第五章 單位時間維護成本最小化之鍋爐預防維護策略------------ 65
5.1預防維護模式之假設----------------------------------------- 66
5.2界定小修、保養與更換-------------------------------------- 67
5.2.1小修------------------------------------------------------- 67
5.2.2保養------------------------------------------------------- 67
5.2.3更換------------------------------------------------------- 67
5.3建立單位時間維護成本最小化之預防維護模式-------- 68
5.3.1模式符號------------------------------------------------- 68
5.3.2預期的成本率------------------------------------------- 68
5.3.3找出最佳的預防維護間隔(x*)與次數(N*)模式-- 71
5.4範例與資料分析----------------------------------------------- 72
5.5結論-------------------------------------------------------------- 76
第六章 維護決策------------------------------------------------------------ 79
6.1保養決策模式-------------------------------------------------- 80
6.1.1以安全考量-----------------------------------------------80
6.1.2以成本考量---------------------------------------------- 80
6.2更換決策模式-------------------------------------------------- 81
6.2.1以可靠度考量------------------------------------------- 82
6.2.1以成本考量---------------------------------------------- 82
6.3範例-------------------------------------------------------------- 82
6.3.1保養決策------------------------------------------------- 82
第七章 結論與後續研究方向--------------------------------------------- 84
7.1結論-------------------------------------------------------------- 84
7.2後續研究方向------------------------------------------------- 86
7.3建議-------------------------------------------------------------- 87
參考文獻------------------------------------------------------------------------- 88
附錄一 鍋爐維護相關名詞解釋------------------------------------------ 94
附錄二 本研究相關數據--------------------------------------------------- 98

圖目錄
圖1-1 中一機鍋爐之剖面圖----------------------------------------------- 5
圖1-2 爐水與蒸汽產生之流程圖----------------------------------------- 6
圖1-3 鍋爐爐水、蒸汽與燃氣熱交換之溫度變化關係圖----------- 7
圖1-4 本研究之研究架構圖-----------------------------------------------16
圖2-1 中一機鍋爐洩漏與熱監視系統之示意圖---------------------- 20
圖2-2 固定間隔維護策略(修理型)之示意圖-------------------------- 22
圖2-3 預定壽命維護策略(更新型)之示意圖-------------------------- 25
圖2-4 鍋爐在定期維護下之可靠度變化圖---------------------------- 28
圖2-5 鍋爐在非定期維護下之可靠度變化圖------------------------- 29
圖3-1 穿過四層熱阻之溫度梯度示意圖------------------------------- 33
圖3-2 在相同熱流通量下不同結垢物厚度對管壁金屬溫度之
影響------------------------------------------------------------------- 33
圖3-3 爐膛水牆管熱監視器之示意圖---------------------------------- 35
圖3-4 乾淨爐管與髒爐管之ΔTi=f(ΔTf)特性圖--------------------- 37
圖3-5 H值與時間之關係圖---------------------------------------------- 37
圖3-6 簡單線性迴歸趨勢線圖------------------------------------------- 39
圖3-7 H值之管制圖------------------------------------------------------- 39
圖3-8 殘差之常態機率點圖---------------------------------------------- 42
圖3-9 殘差對預測值之散佈圖------------------------------------------- 42
圖3-10 殘差對ΔTi=T2-T3(℃)之散佈圖--------------------------------- 43
圖3-11 不同樣本數之ΔTf與ΔTi關係趨勢圖------------------------- 43
圖3-12 TREV30儀用爐管之特性曲線圖------------------------------- 44
圖3-13 表3-4資料中H值與時間之關係圖---------------------------- 47
圖3-14 三種不同趨勢方程式之殘差(時間數列)圖--------------------47
圖3-15 鍋爐預知維護之管制圖-------------------------------------------49
圖4-1 建構爐管預知更換(高溫潛變殘餘壽命)模式之發展圖----- 54
圖4-2 SA213-T22管材之應力破壞與LMP關係圖----------------- 58
圖4-3 不同階段可靠度與累計潛變壽命消耗分數之長期趨勢圖- 62
圖4-4 各期與其累計壽命消耗分數之長期趨勢圖------------------- 62
圖5-1 以單位時間維護成本最小化評估鍋爐預防維護策略之
發展圖---------------------------------------------------------------- 66
圖5-2 定期預防維護之失效率函數圖----------------------------------70
圖5-3 韋伯失效資料之最小平方圖-------------------------------------73
圖5-4 不同α值之預期單位時間維護成本趨勢圖------------------- 77
圖5-5 在Cmr、Cpm與Cre值固定下，不同的α值對x*、N*、
x*N*及C(x*,N*)之變化關係圖-------------------------------- 77
圖6-1 中一機鍋爐儀用爐管之裝設位置圖----------------------------81


表目錄
表1-1 爐管失效之十大主因彙整表---------------------------------------- 9
表3-1 鐵系爐管之規格與其最高可容許之金屬溫度----------------- 40
表3-2 不同熱流通量下ΔTi=T2-T3(℃)之實驗觀察值---------------- 41
表3-3 表3-2資料中ΔTi=T2-T3(℃)之變異數分析結果-------------- 42
表3-4 估計之H值----------------------------------------------------------- 46
表3-5 表3-4資料以三種不同趨勢估計的結果-------------------------47
表4-1 SA213-T22管材於短期高溫時之抗拉強度-------------------- 57
表4-2 不同階段潛變壽命消耗與可靠度關係彙整表----------------- 63
表5-1 依失效時間順序排列之最小平方法適合度資料表------------73
表5-2 以MANN’S檢定Weibull分配適合度之統計量表----------- 74
表5-3 在Cmr=16，Cpm=23之條件下，不同α值與Cre值時之最
佳維護間隔(x*)、維護次數(N*)、更換間隔(x*N*)與預期
成本率(C(x*,N*))之變化關係表---------------------------------78

[01] Alice, J. A., J. A. Janiszewski and D. N. French, “Liquid Ash Corrosion, Remaining Life Estimation and Super-heater/Re-heater Replacement Strategy in Coal Fired Boilers,” Presented at the JT ASME/IEEE Power Generation Conference, Milwaukee, Wisconsin, Paper No. 85-JPGC-PWR-3, October 1985.
[02] Angeli, F., M. Giovannini and C. Michelizzi, “On line monitoring for residual life assessment of fossil power plant high temperature components,” Proceeding. of the EUROTEST International conference, Remanent life：Assessment and extension, March 19-21, 1985.
[03] Asmussen, S., Applied probability and Queues, Wiley series in probability and mathematical statistics, New York, Wiley, 1987.
[04] Auerkari, P., “Remain creep life estimation of old power plant steam piping system,” Advances in life prediction methods, the material conference, Albany, NT, Edit by D. A. Woodford and J. R. Whitehead, pp.353-356, April 18-20, 1983.
[05] Aven, T. and R. Dekker, “A useful framework for optimal replacement models,” Reliability Engineering & System Safety, Vol.58, No.2, pp.61-67, 1997.
[06] Babcock and Wilcox Co., “The Creep Properties of Croloy 2-1/4,” Babcock and Wilcox Co. Tubular Products Division, Beaver Fails, Pennsylvania.
[07] Babcock & Wilcox Company Condition Assessment & Technical Services,“Condition Assessment of Super-heater Tubes for Taiwan Power Corporation, Taichung Station, Unit #2, Foster-Wheeler Unit,” pp.6-7, Inspection Date：November, 1999.
[08] Barlow, R. E, L. C. Hunter, “Preventive maintenance policies,” Operations Research Vol.9, pp.90-100, 1960.
[09] Boland, P. J., “Periodic replacement when minimal repair costs vary with time,” Naval Research Logistics, Vol.29, pp.541-6, 1982.
[10] Canfield, R.V., “Cost optimization of periodic preventive maintenance,” IEEE Transactions on Reliability, Vol.35, pp.78-81, 1986.
[11] CESI BU GENERAZIONE, “Technical note on the monitoring of internal dirt in evaporator pipes using thermo-couples,” Paper presented at technical meeting, 24/25 Nov, 1999.
[12] Chan, P. K. W. and T Downs, “Two criteria for preventive maintenance,” IEEE Transaction on Reliability,Vol.27, pp.272-273, 1978.
[13] Christer, A. H. and W. Wang, “A model of condition monitoring of a production plant,” International Journal of Production Research, Vol.30, No.9, pp.2199-2211.
[14] Chun Y. H., “Optimal number of periodic preventive maintenance operations under warranty,” Reliability Engineering and System Safety, Vol.37, pp.223-225, 1992.
[15] Dekker, R and P. A. Scarf, “On the impact of optimization models in maintenance decision making：the state of the art,” Reliability Engineering and System Safety, Vol.60, No.2, pp.111-120, 1998.
[16] Ebeling, Charles E., University of Dayton, An introduction to reliability and maintainability engineering, International Editions, pp.231-235, 1997.
[17] Montgomery Douglas C., Design and Analysis of experiments, 5th edition, JOHN WILEY & SONS, INC., 2001.
[18] Montgomery Douglas C. and George C. Runger, Applied statistics and probability for engineers, 2nd edition, JOHN WILEY & SONS, INC., 2001.
[19] EPRI, “Remaining life assessment of super-heater and re-heater tubes,” EPRI CS-5564, Prepared by Aptech Engineering Services, Inc. Sunnyvale, California, May 1988.
[20] French, David N., Metallurgical Failures in Fossil Fired Boilers, 2nd edition, A Wiley-Inter-science Publication John WILEY & SONS, INC., pp.3, 1988.
[21] French, David N., Metallurgical Failures in Fossil Fired Boilers, 2nd edition, A Wiley-Inter-science Publication John WILEY & SONS, INC., pp.463-468, 1988.
[22] French, David N., Metallurgical Failures in Fossil Fired Boilers, 2nd edition, A Wiley-Inter-science Publication John WILEY & SONS, INC., pp.468-469, 1988.
[23] French, David. N., Metallurgical Failure in Fossil Fired Boilers, 2nd edition, John Wiley& SONS, INC., 1993.
[24] Foster Wheeler energy corporation,“Operating maintenance instructions for natural circulation steam generator and auxiliaries,” Vol. 1, June 1989.
[25] Grall, Antoine, Laurence Dieull, Christophe Berenguer, and Michel Roussignol,“Continuous-Time Predictive-Maintenance Scheduling for a Deteriorating System,” IEEE Transactions on Reliability, Vol. 51, No.2, June 2002.
[26] IRD Mechanalysis, Inc. “IRD 7090 Predictive maintenance software system”.
[27] Lamping, G. A., R. M. Arrowood, Jr., “Manual for investigation and correction of boiler tube failures,” Prepared by southwest research institute, CS-3945 Research project 1890-1, Final report, April 1985.
[28] Legat, V., A. H. Zaludora, V. Cervenka and V. Jurca, “Contribution to optimization of preventive replacement,” Reliability Engineering & System Safety, Vol.51, No.3, pp.259-266, 1996.
[29] Lie, C. H. and Y. H. Chun, “An algorithm for preventive maintenance policy,” IEEE Transactions on Reliability, Vol.R-35, No.1, pp.71-75, 1986.
[30] Maillart, Lisa M. and Stephen M, Pollock,“Cost-optimal condition-monitoring for predictive maintenance of 2-phase system,” IEEE Transactions on Reliability, Vol. 51, No.3, September 2002.
[31] Marc, A., E. Gallestry, A. Stothert, and S. Morto, “Model predictive control and the optimization of power plant load while considering lifetime consumption,” IEEE Transactions on Reliability, Vol. 17, No.1, February 2002.
[32] Michelizzi, C., R. Tarli, S. Arisi, and R Zavattarelli, “Temperature monitoring of exposed super-heater and re-heater tubes of large fossil-fired boilers,” Proceedings of the American power conference.
[33] Moles, M. D. C. and H. J. Westwood,“ Residual life estimation of high temperature super-heater and re-heater tubing,” CEA RP78-666, Final report prepared by Ontario Hydro Research Division, Toronto, Canada, pp.67-82, March 1982.
[34] Murthy, D. N. P., D. G. Nguyen, “Optimum age-policy with imperfect preventive maintenance,” IEEE Transactions on Reliability, Vol.30, pp.80-81, 1981.
[35] Nakagawa, T and M. Kijima, “Replacement policies for a cumulative damage model with minimal repair at failure” IEEE Transaction on Reliability, Vol.R-27, pp.581-584, 1989.
[36] Nakagawa, T and M. Kijima, “Periodic-replacement models with threshold levels,” IEEE Transaction on Reliability, Vol.R-40, pp.395-397, 1991.
[37] Nakagawa, T., “Optimal policies when preventive are imperfect” IEEE Transactions on Reliability, Vol.28, pp.331-332, 1979.
[38] Nguyen, D. G., D. N. P. Murthy, “Optimal preventive maintenance policies for repairable systems,” Operations Research, Vol.29, pp.1181-1194, 1981.
[39] Park, D. H., G. M. Jung, and J. K. Yum, “Cost minimization for periodic maintenance policy of a system subject to slow degradation,” Reliability Engineering and System Safety vol.68, pp.105-112, 2000.
[40] Pasquantonio, F. and A. Macchi, “Temperatures and stresses in a boiler membrane wall tube,” Nuclear Engineering and Design, vol.31, pp.280-293, July 1974.
[41] Paterson, S. R., T. W. Retting, and K. J. Clark, “Creep damage and remaining life assessment of super-heater and re-heater,” EPRI CS-5208, Life extension and assessment of fossil power plants, pp.455-474, 1987.
[42] Retting, T. W, S. A. Lefton and R. H. Richman, “Creep damage and remaining life of super-heater and re-heater tubes-a useful approach,” EPRI CS-3272, pp.4-22, December 1983.
[43] Stadje, W. and D. Zuckerman, “Optimal strategies for some repair replacement models,” Advances in Applied Probability, Vol.22, No3, pp.641-656, 1990.
[44] Singer, Joseph G., Combustion Engineering, Inc. “Combustion, Fossil Power Systems,”A reference book on fuel burning and steam generation, 3rd edition.
[45] Smith, G. V., “An Evaluation of the Elevated Tensile and Creep-Rupture Properties of Wrought Carbon Steel,” DSIISI, ASTM, Philadelphia, Pennsylvania, 1970.
[46] Smith, G. V., “Evaluation of the Evaluated Temperature Tensile and Creep-Rupture Properties of C-Mo, Mn-Mo, and Mn-Mo-Ni Steels D347,” ASTM, Philadelphia, Pennsylvania, 1971.
[47] Smith, G. V., “Evaluation of the Evaluated Temperature Tensile and Creep-Rupture Properties of 1/2Cr-1/2Mo, 1Cr-1/2Mo, and 1-1/4Cr-1/2Mo Steels,” ASTM, Philadelphia, Pennsylvania, 1973.
[48] Smith, G. V., “Supplement Report on the Elevated Temperature Properties of Cr-Mo Steels(An Evaluation of 2-1/4Cr-1Mo Steel),” DS6S2, ASTM, Philadelphia, Pennsylvania, 1971.
[49] Stultz, S. C. and J. B. Kitto, “STEAM, Its Generation and Use,” The 40th edition, New York Babcock & Wilcox a McDermott Company, pp.45-10~45-11, 1992.
[50] TUBELIFE, Boiler maintenance workstation, Prepared by EPRI, Palo Alto, California and Karta Technology, San Antonia, Texas, February 1990.
[51] Vaurio, J. K., “Optimization of test and maintenance intervals based on risk and cost,” Reliability Engineering & System Safety, Vol.49, pp.23-36,1995.
[52] Viswanathan, R., J. R. Foulds, and D. I. Roberts, “Methods for Estimating the Temperature of Re-heater and Super-heater Tubes in Fossil Plants,” EPRI Research Project 1890, Atlanta, Georgia, Nov., 1987.
[53] Viswanathan, R., S. R. Paterson, H. Grunlon, and S. Gehl, “Life assessment of super-heater/Re-heater tubes in fossil boilers,” American Power Conference, 1995.
[54] Wang, K. S. and C. H. Lin, “Replacement policy about key components of a system,” Processing of the 11th Nat. Conf. of the Chinese Society of Mechanical Engineers, Natiance, Chung Hsing University, Taichung, Taiwan, ROC, pp.595-604, 1994.
[55] Wang, K. S., Y. T. Tsai, and H. J. Po, “A study of preventive maintenance policy for a mechanical system,” submitted to Reliability Engineering and System Safety, 1999.
[56] Wang, Y. C., H. C. Cheng, and W. F. Wu, “Reliability centered maintenance policy,” Proceeding of the Second Symposium on Reliability and Maintainability, Chungli, Taiwan, ROC, pp.223-230, 1997.
[57] Zheng, X. and N. Fard, “A maintenance policy for a repairable systems based on opportunistic failure-rate tolerance,” IEEE Transactions on Reliability, Vol.40, pp.237-244, 1991.
[58] 盧象時、孫常漢、邱遠揚 編著，“火力發電上冊”,中國工程師學會出版pp.133。
[59] 鐘順男 編著，“鍋爐及附屬設備”,前程出版社，中華民國90年6月增訂再版，pp.317-321。
[60] 林春景 著“過熱器及再熱器爐管殘餘壽命評估電腦程式建立”，台灣電力公司八十七年度研究發展專題，中華民國87年6月30日。
[61] 蔡有藤，“系統維護作業之研究”，國立中央大學博士論文，1999。
[62] 許金和，“火力發電大全”，高雄復文圖書出版社，2001。