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短期的・長期的運転停止中のCCGT(複合火力発電) & 従来型発電所の予防ガイドライン

Preservation Guidelines for CCGT & Conventional Power Plant during Short- and Long-Term Shutdowns

発行 ETD Consulting 商品コード 312605
出版日 ページ情報 英文
納期: 即日から翌営業日
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本日の銀行送金レート: 1USD=102.12円で換算しております。
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短期的・長期的運転停止中のCCGT(複合火力発電) & 従来型発電所の予防ガイドライン Preservation Guidelines for CCGT & Conventional Power Plant during Short- and Long-Term Shutdowns
出版日: 2013年06月30日 ページ情報: 英文
概要

近年、天然ガス価格の急騰、新規の発電容量の供給過剰および再生可能エネルギーの貢献増加により、コンバインドサイクル発電(CCGT)およ従来型発電所(CPP)はサイクルモードでの操業もしくは数カ月間かそれ以上の運転停止を余儀なくされています。運転停止期間中の腐食損傷の予防は大きな課題であり、それによって、デコミッショニング段階とそれに続くサービス期間中のプラントの信頼性への影響を最小化します。

当レポートでは、短期・長期にわたって運転停止されるCCGT(複合火力発電)および従来型発電所(CPP)に用いられる予防技術について調査し、レイアップ実施・予防技術に関する情報、およびプラントオペレーターのエクスペリエンス調査などから、予防ガイドラインを提示しています。

エグゼクティブサマリー

第1章 イントロダクション

第2章 概論

第3章 ボイラー/HRSG & FEEDシステム、スチームタービンおよびコンデンサー

  • ストレージの理由・選択肢
  • 乾式貯蔵
  • 湿式貯蔵
  • 部分的に排水されたプラント向けの貯蔵技術
  • 補助ボイラー
  • 計装

第4章 水処理プラント・冷却水システム

第5章 回転子軸受

第6章 タービン発電機オイルシステム

第7章 システム制御バルブ

第8章 燃料システム

第9章 その他のマテリアルハンドリングシステム

第10章 ガスタービン

第11章 電気設備

  • 発電機
  • 変圧器
  • モーター
  • 電気室
  • 制御室・その他の部屋
  • カソード防食システム

付録1:揮発性薬品を用いた湿式レイアップ

付録2:非揮発性薬品を用いた湿式レイアップ

付録3:リン酸三ナトリウムを用いたフィル・ドレインレイアップ

付録4:窒素充填・キャップ

付録5:湿度・除湿

付録6:コンデンサーバキュームポンプを用いたドライアウト

付録7: オーステナイト系・酸化銅合金が存在する際のレイアップ

付録8:ボイラーファイアサイド

付録9:油圧テスト

付録10:システムタービンのレイアップ

付録11:交流発電機

付録12:ポンプ

付録13:脱気装置

付録14:コンデンサー、熱交換器および排気装置

付録15:パッシベーションのプールべ図解

図表リスト

目次
Product Code: 1274-gsp-188

In recent years, the rapidly increasing price of natural gas, overbuilding of new generating capacity and increasing contribution of renewable energy have been forcing more and more Combined Cycle Gas Turbine (CCGT) and Conventional Power Plant (CPP) units to be operated in cycling mode or to be shut down for extended periods of up to several months or more. The major issue with long periods of inactivity is prevention of corrosion damage during the shutdown period, thereby minimizing the impact on the plant's reliability during the recommissioning phase and subsequent service. Failure to apply proper lay-up or preservation techniques during the shutdown period will result in significant corrosion damage to plant equipment during the shutdown period, and damage accumulation during operation will be exacerbated.

It is important when planning a lay-up to consider the whole unit and not just the obvious components such as the boiler. There are many areas of plant to be considered. For a conventional station the items may include the plant areas shown below.

  • a. Fuel systems
  • b. Boiler water-side
  • c. Boiler gas-side
  • d. Steam turbine - steam-side
  • e. Steam turbine - oil system and periodic rotation of rotors
  • f. Generators
  • g. Condensers
  • h. Feed water systems
  • i. Cooling water systems
  • j. Water treatment plant and water storage
  • k. Transformers
  • l. Switchgear
  • m. Ash systems
  • n. Dust systems
  • o. Flue gas treatment systems.

Excluding the fuel / ash and dust systems, and with the obvious addition of the GT and replacement of a boiler by the HRSG, the plant areas listed above also cover CCGT units.

As conventional stations are usually fired by heavy fuel oil or coal then these fuel systems will need some preparation and care during a lay-up. Similarly coal-fired stations have ash and dust removal systems. Some have flue gas treatment systems (such as flue gas desulphurisation), all of which need some work for lay-up.

Many of the lay-up procedures are designed to avoid corrosion of metal components with all of the subsequent issues that this can bring. For corrosion to take place it is generally necessary to have moisture and oxygen present. Removing either the moisture or the oxygen will significantly reduce if not totally eliminate corrosion.

The length of the lay-up and the climate (atmospheric conditions) will both have a very significant impact on the lay-up methods used and potential problems to be faced both during the lay-up and upon return to service. In general, 'wet lay-up' is preferred for short shutdown periods and 'dry lay-up' is preferred for longer periods, although the choice may be complicated by various factors. Lay-ups will in some situations be determined by grid demand with little or no prior notice and, similarly, the likely duration of the lay-up will be unknown with only a short notice period prior to return to service. The confidence of the estimation of the length of the lay-up or the desire to retain the ability to return the plant quite quickly to service may influence some of the methods used.

This study covers the preservation techniques used for CCGT and CPP units that will be shut down for short or extended periods, i.e. both the wet and dry storage methods. Information on lay-up practices and preservation techniques has been brought together from published and unpublished sources and critically analysed by ETD preservation experts and in addition a survey of plant operator experience was carried out to examine the preservation procedures that have been/ are being used by some of the participating utilities. Further to critically analysing and putting together above knowledgebase and experience, the experience of ETD's own experts in power plant chemistry, corrosion and operation/ maintenance of mechanical plant and electrical equipment played a crucial role in formulating these guidelines.

To make it easier for the power plant engineers and management to implement these Guidelines a Summary Table and a set of Diagrams/ Flow Charts have been produced. Furthermore, a set of fifteen Appendices has been

Table of Contents

Executive Summary

List of Tables

List of Figures

1. INTRODUCTION

2. GENERAL CONSIDERATIONS

  • 2.1 Lay-up Monitoring and Maintenance
  • 2.2 Start-up

3. BOILERS / HRSGs & FEED SYSTEMS, STEAM TURBINES & CONDENSERS

  • 3.1 Reasons and Options for Storage
    • 3.1.1 General
    • 3.1.2 Shutdown Period
    • 3.1.3 Outline of the Lay-up Options
    • 3.1.4 References / Bibliography
  • 3.2 Dry Storage
    • 3.2.1 General
    • 3.2.2 Complete Dry-Out
    • 3.2.3 The Process Details
    • 3.2.4 Other Dry Storage Methods
  • 3.3 Wet Storage
    • 3.3.1 General
    • 3.3.2 Different Lay-up Requirements for Feed and Condensate Systems and Boilers
    • 3.3.3 Volatile Chemical Wet Storage Solutions
    • 3.3.4 Non-Volatile Wet Storage Solutions
    • 3.3.5 Inspection and Testing
    • 3.3.6 Sampling
    • 3.3.7 Results and Action Required
    • 3.3.8 Cold Weather Storage
    • 3.3.9 Disposal of Lay-up Solutions
  • 3.4 Storage Techniques for Partially Drained Plant
    • 3.4.1 Nitrogen Filling
    • 3.4.2 Inhibition of Retained Water by Nitrite-Borax
    • 3.4.3 Inhibition of Retained Water by Tri-Sodium Phosphate (TSP)
  • 3.5 Auxiliary Boiler
  • 3.6 Instrumentation

4. WATER TREATMENT PLANT & COOLING WATER SYSTEMS

5. ROTOR BEARINGS

6. TURBINE GENERATOR OIL SYSTEMS

7. STEAM CONTROL VALVES

8. FUEL SYSTEMS

9. OTHER MATERIALS HANDLING SYSTEMS

10. GAS TURBINES

11. ELECTRICAL EQUIPMENT

  • 11.1 Generators
  • 11.2 Transformers
  • 11.3 Motors
  • 11.4 Switch Rooms
  • 11.5 Control Rooms & Other Rooms
  • 11.6 Cathodic Protection System

APPENDIX 1: WET LAY-UP USING VOLATILE CHEMICALS

  • A.1.1 Procedures
  • A.1.2 Storage of Feedheaters and Deaerators
  • A.1.3 Cascading Blowdown

APPENDIX 2: WET LAY-UP USING NON-VOLATILE CHEMICALS

  • A.2.1 Storage of Un-Drained or Partially Drained Plant
  • A.2.2 Disposal of Effluents

APPENDIX 3: FILL AND DRAIN LAY-UP USING TRI-SODIUM PHOSPHATE

APPENDIX 4: NITROGEN FILLING AND CAPPING

  • A.4.1 General
  • A.4.2 Nitrogen Filling
  • A.4.3 Nitrogen Capping

APPENDIX 5: HUMIDITY AND DEHUMIDIFICATION

APPENDIX 6: DRY-OUT USING CONDENSER VACUUM PUMPS

APPENDIX 7: LAY-UP WHEN AUSTENITIC AND CUPROUS ALLOYS ARE PRESENT

APPENDIX 8: BOILER FIRESIDE

  • A.8.1 Fireside Corrosion Losses
  • A.8.2 CCGT Start-up Emissions
  • A.8.3 Stack Corrosion
  • A.8.4 Treatment Options

APPENDIX 9: HYDRAULIC TESTING

APPENDIX 10: LAY-UP OF STEAM TURBINES

  • A.10.1 General
  • A.10.2 Short Turnaround using Hot Dry Storage
  • A.10.3 Long-Term Lay-Up using Cold Dry Conditions

APPENDIX 11: ALTERNATORS

APPENDIX 12: PUMPS

APPENDIX 13: DEAERATORS

APPENDIX 14: CONDENSERS, HEAT EXCHANGERS AND AIREJECTORS

  • A.14.1 Air-Cooled Condensers

APPENDIX 15: POURBAIX EXPLANATION OF PASSIVATION

  • A.15.1 Construction of a Pourbaix Diagram
  • A.15.2 The Nernst Equation
  • A.15.3 Applying the Pourbaix Diagrams to Iron and Copper/Brass
  • A.15.4 Second Stage Passivation
  • A.15.5 Chromium Steel Turbine Blades

LIST OF TABLES

  • TABLE 1: SUMMARY OF STORAGE PROCEDURES

LIST OF FIGURES

  • DIAGRAM 1: PRE-COMMISSIONING PLANT STORAGE
  • DIAGRAM 2: POST-SERVICE BOILERS AND ASSOCIATED PIPEWORK
  • DIAGRAM 3: POST-SERVICE FEED SYSTEMS
  • DIAGRAM 4: POST-SERVICE CONDENSERS AND STEAM TURBINES
  • DIAGRAM 5: PRE-SERVICE AND POST-SERVICE FIRESIDE
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