{"id":1681,"date":"2021-07-07T15:55:59","date_gmt":"2021-07-07T15:55:59","guid":{"rendered":"https:\/\/www.thepyroscope.com\/blog\/?p=1681"},"modified":"2024-05-29T02:06:35","modified_gmt":"2024-05-29T02:06:35","slug":"automatic-variable-ratio-firing-of-a-blend-of-free-and-purchased-fuels","status":"publish","type":"post","link":"https:\/\/www.thepyroscope.com\/blog\/automatic-variable-ratio-firing-of-a-blend-of-free-and-purchased-fuels\/","title":{"rendered":"Automatic, Variable Ratio, Firing of a Blend of \u201cFree\u201d and Purchased Fuels"},"content":{"rendered":"\n

-Peter Lavelle, Danbury CT<\/em><\/p>\n\n\n

\n
\"\"<\/a><\/figure><\/div>\n\n\n

\u201cFree\u201d fuels are available from many processes: Digester Gas from wastewater treatment plants, Bio-Gas from agricultural and food processing plant waste, Hydrogen from chemical plants, Off-Gases from a Refinery, etc. <\/p>\n\n\n\n

The Challenge<\/strong><\/p>\n\n\n\n

Firing these \u201cfree\u201d fuels in a boiler, process heater, or engine-generator significantly reduces operating costs and can significantly reduce greenhouse gas emissions. However, the Btu content and flow rate of these \u201cfree\u201d fuels vary based on the Processing Plant operations, are frequently insufficient to meet the steam, hot water, or electrical output required from the Utility Plant. <\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The Solution<\/strong><\/p>\n\n\n\n

A simplistic approach to satisfying the Utility Plant output demand is to run multiple units with some burning only \u201cfree\u201d fuel, and some burning only Purchased fuel. Besides the higher capital cost for multiple units, this can also result in units running at lower loads and thus lower efficiencies. Even worse, it can result in units with low turndown capability to continuously cycle on\/off \u2013further lowering efficiency, and potentially upsetting the Process Plant operations.<\/p>\n\n\n\n

A better approach is to provide a control system and burner that\nallows multiple fuels to be fired simultaneously in a single unit with a variable\nFuel Ratio (\u201cfree\u201d fuel versus Purchased fuel). The control logic is designed\nto burn as much \u201cfree\u201d fuel as possible while simultaneously meeting the Plant demand\nfor Steam, Hot Water, or Electrical Output.   <\/p>\n\n\n\n

The Fuel Ratio is automatically determined by a level or pressure\ntransmitter that indicates the \u201cfree\u201d fuel availability. When \u201cfree\u201d fuel\navailability trends lower, the Fuel Ratio smoothly shifts to burn more\nPurchased fuel..without shutting down. When \u201cfree\u201d fuel availability trends\nhigher, the Fuel Ratio shifts to more \u201cfree\u201d fuel \u2013without shutting down. <\/p>\n\n\n\n

For both approaches (multiple single fuel units versus blended\nfuel units), if the Btu content of the \u201cfree\u201d fuel varies significantly, then a\nMethane or Wobbe analyzer may be required to maintain an adequate fuel\/air\nratio.  <\/p>\n\n\n\n

If a burner has multiple fuel injectors, the blending can occur in the furnace. An external fuel blending skid can also be used for any burner, but a blending skid is required for an engine generator. <\/p>\n\n\n\n

Our Experience<\/strong><\/p>\n\n\n\n

Preferred Utilities has been manufacturing state-of-the-art combustion controllers and burners for over 40 years. Preferred has provided Variable Ratio, Blended-Fuel systems for over 30 years. Systems have ranged in size from a single 75 Bhp (2.6 klbs\/hr) boiler, to multiple 250 klbs\/hr boilers, and multiple 3 MWe (continuous) Engine-Generators. \u201cFree\u201d fuel powered Combustion Joy!<\/p>\n","protected":false},"excerpt":{"rendered":"

-Peter Lavelle, Danbury CT \u201cFree\u201d fuels are available from many processes: Digester Gas from wastewater treatment plants, Bio-Gas from agricultural and food processing plant waste, Hydrogen from chemical plants, Off-Gases from a Refinery, etc. The Challenge Firing these \u201cfree\u201d fuels in a boiler, process heater, or engine-generator significantly reduces operating costs and can significantly reduce greenhouse gas emissions. […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"content-type":"","footnotes":""},"categories":[13,7],"tags":[],"_links":{"self":[{"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/posts\/1681"}],"collection":[{"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/comments?post=1681"}],"version-history":[{"count":8,"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/posts\/1681\/revisions"}],"predecessor-version":[{"id":2312,"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/posts\/1681\/revisions\/2312"}],"wp:attachment":[{"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/media?parent=1681"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/categories?post=1681"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.thepyroscope.com\/blog\/wp-json\/wp\/v2\/tags?post=1681"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}