{"id":631,"date":"2019-01-13T20:14:32","date_gmt":"2019-01-13T20:14:32","guid":{"rendered":"http:\/\/johnbrear-plantintegrity.com\/?page_id=631"},"modified":"2019-01-14T09:53:35","modified_gmt":"2019-01-14T09:53:35","slug":"phase-1-boiler-life-assessment","status":"publish","type":"page","link":"https:\/\/johnbrear-plantintegrity.com\/?page_id=631","title":{"rendered":"Phase 1 boiler life assessment"},"content":{"rendered":"<p><img fetchpriority=\"high\" decoding=\"async\" src=\"http:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/Aghada.jpg\" alt=\"the subject power plant - courtesy of the utility\" width=\"456\" height=\"245\" class=\"alignright size-full wp-image-639\" srcset=\"https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/Aghada.jpg 912w, https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/Aghada-300x161.jpg 300w, https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/Aghada-768x413.jpg 768w\" sizes=\"(max-width: 456px) 100vw, 456px\" \/><\/p>\r\n<p><strong>Plant:<\/strong><\/p>\r\n<ul>\r\n    <li>A 270 MW gas fired boiler, of once-through (Benson) type with 180,000h service.<\/li>\r\n    <li>After 5 years base-load operation followed by 20 years of load following, the utility wishes to run in a two-shifting regime for 8 more years.<\/li>\r\n<\/ul>\r\n<p><strong>Objective:<\/strong><\/p>\r\n<p>A <a href=\"http:\/\/johnbrear-plantintegrity.com\/?page_id=432\">Phase 1<\/a> remaining life assessment of:<\/p>\r\n<ul>\r\n    <li>all critical headers (22 types)<\/li>\r\n    <li>some internal pipework (2 bends)<\/li>\r\n    <li>some tubes (2 banks)<\/li>\r\n<\/ul>\r\n<p><strong>Basis of assessment:<\/strong><\/p>\r\n<ul>\r\n    <li>Current condition (calculated life consumed) <br \/>\r\n    &#160;- operating conditions to date<\/li>\r\n    <li>Remaining life<br \/>\r\n    &#160;- proposed change from load following to two shifting<\/li>\r\n    <li>Mechanisms<br \/>\r\n    &#160;- low temperature headers - fatigue only<br \/>\r\n    &#160;- high temperature components - creep and fatigue<br \/>\r\n    &#160;- tubes - creep, fireside corrosion, steamside corrosion<\/li>\r\n    <li>Input data<br \/>\r\n    &#160;- actual and expected operating conditions<br \/>\r\n    &#160;- design materials data and dimensions<\/li>\r\n    <li>Code based stress analysis (TRD) <br \/>\r\n    &#160;- all key locations<\/li>\r\n<\/ul>\r\n<p><strong>Operational events considered:<\/strong><\/p>\r\n<ul>\r\n    <li>Starts<br \/>\r\n    &#160;- Cold to 40 MW<br \/>\r\n    &#160;- Cold to full load<br \/>\r\n    &#160;- Warm to full load<br \/>\r\n    &#160;- Hot to full load<\/li>\r\n<\/ul>\r\n<ul>\r\n    <li>Load changes<br \/>\r\n    &#160;- 40 \u2013 270<br \/>\r\n    &#160;- 270 \u2013 40 MW<br \/>\r\n    &#160;- 80 \u2013 160 MW<br \/>\r\n    &#160;- 40 \u2013 270 \u2013 130 \u2013 270 \u2013 40 MW (full 24h cycle)<\/li>\r\n<\/ul>\r\n<ul>\r\n    <li>Unit trip<\/li>\r\n<\/ul>\r\n<p><strong>Excursions and instabilities:<\/strong><\/p>\r\n<p>Known in advance:<\/p>\r\n<ul>\r\n    <li>Economiser<br \/>\r\n    &#160;- cold-water pull-through from de-aerator on run-up<\/li>\r\n    <li>Evaporator, level maintaining vessel, cyclones<br \/>\r\n    &#160;- feedwater choke on transition to once-through operation<\/li>\r\n<\/ul>\r\n<p>Discovered during the assessment:<\/p>\r\n<ul>\r\n    <li>Superheaters 3 and 4, Reheater 2<br \/>\r\n    &#160;- Attemporator instability<\/li>\r\n    <li>Reheater 1<br \/>\r\n    &#160;- Bypass instability<\/li>\r\n<\/ul>\r\n<figure id=\"attachment_637\" aria-describedby=\"caption-attachment-637\" style=\"width: 980px\" class=\"wp-caption alignright\"><img decoding=\"async\" src=\"http:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/SH3-instabilities.jpg\" alt=\"\" width=\"980\" height=\"600\" class=\"size-full wp-image-637\" srcset=\"https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/SH3-instabilities.jpg 1226w, https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/SH3-instabilities-300x184.jpg 300w, https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/SH3-instabilities-768x470.jpg 768w, https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/SH3-instabilities-1024x626.jpg 1024w\" sizes=\"(max-width: 980px) 100vw, 980px\" \/><figcaption id=\"caption-attachment-637\" class=\"wp-caption-text\">Operational data for Superheater 3, showing attemperator-induced instabiity<\/figcaption><\/figure>\r\n<p><strong>Results - fatigue:<\/strong><\/p>\r\n<ul>\r\n    <li>Two components were calculated to be fatigue critical at the assessment time<\/li>\r\n    <li>If instabilities have their maximum effect, then a further component was also calculated to be fatigue critical at the assessment time<\/li>\r\n    <li>Three components were calculated to become fatigue critical during the next 8 years<\/li>\r\n    <li>If instabilities have their maximum effect, then a further component was also calculated to become fatigue critical during the next 8 years<\/li>\r\n<\/ul>\r\n<p><strong>Results - creep and fatigue combined:<\/strong><\/p>\r\n<ul>\r\n    <li>Two components were calculated to be creep strain critical at the assessment time<\/li>\r\n    <li>One of these was also critical with regard to calculated total damage at the assessment time and the calculated total damage was predicted to exceed 1 within the next 8 years<\/li>\r\n    <li>The other was predicted to become critical with respect to calculated total damage during the next 8 years<\/li>\r\n<\/ul>\r\n<p><strong>Recommendations:<\/strong><\/p>\r\n<ul>\r\n    <li>Further data, necessary to refine the assessment for those components which were predicted to become critical within the next 8 years, were identified<\/li>\r\n    <li>Future inspection plans were formulated<br \/>\r\n    &#160;- Scope and timing<br \/>\r\n    &#160;- Techniques<\/li>\r\n    <li>Potential replacements were identified<\/li>\r\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>Plant: A 270 MW gas fired boiler, of once-through (Benson) type with 180,000h service. After 5 years base-load operation followed by 20 years of load following, the utility wishes to run in a two-shifting regime for 8 more years. Objective: A Phase 1 remaining life assessment of: all critical headers (22 types) some internal pipework &hellip; <a href=\"https:\/\/johnbrear-plantintegrity.com\/?page_id=631\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Phase 1 boiler life assessment<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":114,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-631","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/631","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=631"}],"version-history":[{"count":9,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/631\/revisions"}],"predecessor-version":[{"id":633,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/631\/revisions\/633"}],"up":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/114"}],"wp:attachment":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=631"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}