{"id":1676,"date":"2019-09-24T15:29:53","date_gmt":"2019-09-24T19:29:53","guid":{"rendered":"https:\/\/www.environex.com\/?p=1676"},"modified":"2019-09-24T15:29:53","modified_gmt":"2019-09-24T19:29:53","slug":"advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges","status":"publish","type":"post","link":"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/","title":{"rendered":"Advanced Class Gas Turbine SCR and CO Catalyst System Operating Challenges"},"content":{"rendered":"<p>\nOne of the tradeoffs for the higher efficiency of new advanced class gas turbines (namely the G-, H-, and J-class machines) is <span class=\"emphasis\">increased thermal NOx make<\/span>, which is caused by higher firing temperatures in the gas turbine combustors.  The result is GT exit NOx concentrations in the 25 \u2013 35 ppmvdc range for the advanced class turbines, which is significantly higher than the 9 \u2013 20 ppmvdc range for their F-class predecessors.\n<\/p>\n<p>\nSince regulators tend to view all gas turbines as being the same, they assume that the same stack emissions levels can be met regardless of the turbine technology.  Because of this, the advanced class turbines are expected to achieve the same stack emissions levels as F-class machines <span class=\"emphasis\">without giving consideration<\/span> to the differences in combustion dynamics between the different classes of turbines.\n<\/p>\n<p>\nModern day F-class machines are expected to achieve stack limits of 2.0 \u2013 2.5 ppmvdc NOx and 2.0 \u2013 5.0 ppmvdc ammonia slip through the use of selective catalytic reduction (SCR) systems, which use ammonia as the reducing agent to convert NOx across a catalyst.  These systems provide 72 \u2013 90% NOx reduction while being allowed to slip 22 \u2013 25% excess ammonia (2 ppm NH3 slip\/9 ppm inlet NOx to 5 ppm NH3 slip\/20 ppm inlet NOx).  By contrast, the advanced class machines <span class=\"emphasis\">must provide 90 \u2013 94% NOx conversion<\/span> while only being allowed to slip 7 \u2013 8% excess ammonia to achieve the same stack emissions levels.\n<\/p>\n<p>\nThis is increase in required NOx reduction accompanied by the decrease in allowable excess ammonia results in increased SCR system performance requirements that are by no means trivial.  As NOx conversion requirements increase to 90% and above, the systems have <span class=\"emphasis\">much less tolerance<\/span> for non-ideal performance, particularly with such low levels of allowable excess ammonia.  As a result, SCR systems for advanced class turbines require higher SCR catalyst volumes, near-perfect ammonia-to-NOx distribution, and air-tight seals around the SCR catalyst perimeter and all catalyst modules.  In order to reliably meet stack emissions requirements, these sites will need <a href=\"\/catalyst-services-business-groups\/industrial-catalyst-management-services\/catalyst-lifecycle-management\" class=\"ul_link\" alt=\"SCR Catalyst System Management\">pro-active SCR management plans<\/a> that include <a href=\"\/catalyst-services-business-groups\/industrial-catalyst-management-services\/ammonia-injection-grid-tuning\" class=\"ul_link\" alt=\"Ammonia Tuning\">proper ammonia injection grid design and tuning<\/a>, a <a href=\"\/catalyst-services-business-groups\/industrial-catalyst-management-services\/full-scr-system-evaluation\" alt=\"Full SCR System Evaluation\" class=\"ul_link\">catalyst testing program that takes into account all plant operating modes<\/a>, thorough catalyst system maintenance, and <a href=\"\/catalyst-services-business-groups\/industrial-catalyst-management-services\/scr-catalyst-replacement-services\" alt=\"SCR Catalyst Replacement Services\" class=\"ul_link\">proper design and selection of replacement catalyst that adapts to changing SCR system needs<\/a>.\n<\/p>\n<p>\nAdditional challenges for advanced class turbine SCR and CO catalyst systems are the requirements for low turndown operation, fast start-ups, and frequent cycling.  Historically, gas turbines have only been required to operate down to 50% of baseload.  Many of the new, advanced class sites are being asked to operate at loads as low as 20%, start up and achieve emissions compliance within shorter timeframes, and to cycle frequently between low loads and baseload.  These requirements put <span class=\"emphasis\">additional stress on catalyst systems<\/span>, primarily attributed to sub-optimal operating temperatures and elevated gas turbine NOx and CO emissions under these operating conditions.\n<\/p>\n<p>\n<a href=\"http:\/\/www.ccj-online.com\/ccj-issue-58\/emissions-control-latest-gts-pose-special-challenges-for-nox-co-catalyst-system-design\/\" class=\"ul_link\">For the full CCJ article, please click here<\/a>.\n<\/p>\n<p><img decoding=\"async\" src=\"\/wp-content\/images\/insights\/Design_Requirements.gif\" title=\"SCR Design Requirements\" alt=\"SCR System Design Requirements Matrix\"\/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>One of the tradeoffs for the higher efficiency of new advanced class gas turbines (namely the G-, H-, and J-class machines) is increased thermal NOx make, which is caused by higher firing temperatures in the gas turbine combustors. The result is GT exit NOx concentrations in the 25 \u2013 35 ppmvdc range for the advanced [&hellip;]<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"advgb_blocks_editor_width":"","advgb_blocks_columns_visual_guide":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[15,6,7,12,9],"tags":[],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v21.9.1 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Advanced Class Gas Turbine SCR and CO Catalyst System Operating Challenges - Environex<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Advanced Class Gas Turbine SCR and CO Catalyst System Operating Challenges - Environex\" \/>\n<meta property=\"og:description\" content=\"One of the tradeoffs for the higher efficiency of new advanced class gas turbines (namely the G-, H-, and J-class machines) is increased thermal NOx make, which is caused by higher firing temperatures in the gas turbine combustors. The result is GT exit NOx concentrations in the 25 \u2013 35 ppmvdc range for the advanced [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/\" \/>\n<meta property=\"og:site_name\" content=\"Environex\" \/>\n<meta property=\"article:published_time\" content=\"2019-09-24T19:29:53+00:00\" \/>\n<meta name=\"author\" content=\"Erica King\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Erica King\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/\",\"url\":\"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/\",\"name\":\"Advanced Class Gas Turbine SCR and CO Catalyst System Operating Challenges - Environex\",\"isPartOf\":{\"@id\":\"https:\/\/environex.com\/#website\"},\"datePublished\":\"2019-09-24T19:29:53+00:00\",\"dateModified\":\"2019-09-24T19:29:53+00:00\",\"author\":{\"@id\":\"https:\/\/environex.com\/#\/schema\/person\/69c005a57ac59bc01c93ee860b972b6c\"},\"breadcrumb\":{\"@id\":\"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/environex.com\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Advanced Class Gas Turbine SCR and CO Catalyst System Operating Challenges\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/environex.com\/#website\",\"url\":\"https:\/\/environex.com\/\",\"name\":\"Environex\",\"description\":\"Excellence At the Highest Level\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/environex.com\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/environex.com\/#\/schema\/person\/69c005a57ac59bc01c93ee860b972b6c\",\"name\":\"Erica King\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/environex.com\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/d5bf87a5e07075d8b2a783ad1f0919fb?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/d5bf87a5e07075d8b2a783ad1f0919fb?s=96&d=mm&r=g\",\"caption\":\"Erica King\"},\"url\":\"https:\/\/environex.com\/author\/eking\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Advanced Class Gas Turbine SCR and CO Catalyst System Operating Challenges - Environex","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/","og_locale":"en_US","og_type":"article","og_title":"Advanced Class Gas Turbine SCR and CO Catalyst System Operating Challenges - Environex","og_description":"One of the tradeoffs for the higher efficiency of new advanced class gas turbines (namely the G-, H-, and J-class machines) is increased thermal NOx make, which is caused by higher firing temperatures in the gas turbine combustors. The result is GT exit NOx concentrations in the 25 \u2013 35 ppmvdc range for the advanced [&hellip;]","og_url":"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/","og_site_name":"Environex","article_published_time":"2019-09-24T19:29:53+00:00","author":"Erica King","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Erica King","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/","url":"https:\/\/environex.com\/industrial-catalyst-services\/advanced-class-gas-turbine-scr-and-co-catalyst-system-operating-challenges\/","name":"Advanced Class Gas Turbine SCR and CO Catalyst System Operating Challenges - 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King","author_link":"https:\/\/environex.com\/author\/eking\/"},"featured_img":null,"coauthors":[],"tax_additional":{"categories":{"linked":["<a href=\"https:\/\/environex.com\/category\/advanced-gas-turbine\/\" class=\"advgb-post-tax-term\">advanced gas turbine<\/a>","<a href=\"https:\/\/environex.com\/category\/industrial-catalyst-services\/\" class=\"advgb-post-tax-term\">industrial catalyst services<\/a>","<a href=\"https:\/\/environex.com\/category\/nox\/\" class=\"advgb-post-tax-term\">NOx<\/a>","<a href=\"https:\/\/environex.com\/category\/operating-data-analysis\/\" class=\"advgb-post-tax-term\">operating data analysis<\/a>","<a href=\"https:\/\/environex.com\/category\/selective-catalytic-reduction\/\" class=\"advgb-post-tax-term\">selective catalytic reduction<\/a>"],"unlinked":["<span class=\"advgb-post-tax-term\">advanced gas turbine<\/span>","<span class=\"advgb-post-tax-term\">industrial catalyst services<\/span>","<span class=\"advgb-post-tax-term\">NOx<\/span>","<span class=\"advgb-post-tax-term\">operating data analysis<\/span>","<span class=\"advgb-post-tax-term\">selective catalytic reduction<\/span>"]}},"comment_count":"0","relative_dates":{"created":"Posted 5 years ago","modified":"Updated 5 years ago"},"absolute_dates":{"created":"Posted on September 24, 2019","modified":"Updated on September 24, 2019"},"absolute_dates_time":{"created":"Posted on September 24, 2019 3:29 pm","modified":"Updated on September 24, 2019 3:29 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