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Georgia’s Experience with Wood Pellet Plants. R4 Enforcement Managers Workshop November 2012. What is a Wood Pellet?. Compacted sawdust Lignin in wood forms the “glue” holding the pellet together after going through the press area (heat and pressure ). Wood Pellets.
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Georgia’s Experience with Wood Pellet Plants R4 Enforcement Managers Workshop November 2012
What is a Wood Pellet? • Compacted sawdust • Lignin in wood forms the “glue” holding the pellet together after going through the press area (heat and pressure)
Wood Pellets • Manufactured to a specific size and density • Even heating • Facilitate automatic feeding • Moisture content reduced to < l0% • No bark used, so the ash content is low • ~7500 BTU/lb
Wood Pellets • Most wood pellets produced in GA are shipped to Europe • Pellets are used to generate electricity in UK and Netherlands, as well as for home heating
Wood Pellet Process Diagram PM, VOC & HAP controls Raw material (sawdust/ bark) Heat Energy System Heat Wet chips Raw material (logs) Debarker, Chipper Dryer PM controls Dry chips Hot Pellets Hammermill Pelletizer Cooler Pellet Bagging/ Bulk Loading Flakes
Case Study 1 Plant converted from producing pine shavings for animal bedding to manufacturing wood pellets for European markets. • 40 MM Btu/hour burner provides direct heat to triple pass drum dryer • High efficiency cyclone on triple pass drum dryer recycles product back into the process • Initially permitted with a major source construction permit • Required to conduct performance tests for CO, VOC, PM after startup
Case Study 1 • Performance tests conducted at Facility in August 2009 • Synthetic minor source operating permit was issued • Emission factors developed from August 2009 tests used • Synthetic minor source of VOCs • Permit limited throughput to 59,353 tons of green wood during any 12 consecutive months (equivalent to 33,000 ODT) to limit VOC emissions • PTE for PM and CO determined to be < 100 TPY based on emission factors developed during August 2009 performance test
Case Study 1 • GA EPD’s Industrial Source Monitoring Program conducted VOC, CO, NOx, and opacity testing in November 2011 at Facility • High VE observed from dryer • Noted that combustion control was not sophisticated • Standard industry and EPA emission factors were not available for industry
Case Study 1 • Notice of Violation (NOV) issued in August 2012 • Cited a violation of 40% opacity limit • Stated that the tests conducted by GA EPD in Nov 2011 indicate potential Title V and PSD violations for CO and VOC • Requested a demonstration of compliance with emission limits or submittal of a PSD application
Case Study 1 • NOV response received in November 2012 and detailed actions taken by Company since November 2011 testing • Added variable speed drive to dryer burner fans and ID fan • Operator training • Redesigned air inlet ducts into burner chamber • Redesigned dryer feed to reduce cold air inflow • NOV response did not include schedule for conducting additional performance tests • NOV response did not include PSD application
Case Study 2 • Greenfield Plant in South Georgia • Plant production rate of 750,000 metric tons per year (826,733 short tons) • Two heat energy systems, each with design capacity of 193 MM Btu/hr • Emissions from heat energy systems and rotary drum dryer are controlled with Wet ESPs and thermal oxidizers • Hammermills and pellet cooler line emissions are controlled with baghouses
Case Study 2 • Permitted as Title V major source and PSD minor source • Synthetic minor limits for formaldehyde and total HAP • Title V major source of PM, VOCs, CO and NOx
Case Study 2 • Began operating in April 2011 • Conducted testing in October 2011 as required by the Permit • VOCs, NOx, CO, PM, formaldehyde, methanol, acetaldehyde off dryers (as controlled by WESP and thermal oxidizers) • Demonstrated compliance with all emission limits in the Permit
Case Study 2 • Met with GA EPD in June 2012 to self-disclose potential PSD violations • Discovered during engineering testing • VOC emissions significantly higher than projected • Significant amount of VOCs coming from pellet coolers and hammermills (not just the dryers) • Requested time to do additional testing • Additional testing done in July 2012 was received at GA EPD in September 2012 • VOC emissions ~ 1300 TPY
Case Study 2 • Company has submitted a compliance schedule to install two additional thermal oxidizers • Hammermills • Pellet coolers • Plans to remain a PSD minor
Questions? Douglas Waldron Douglas.Waldron@gaepd.org 404-363-7122 Karen Hays Karen.Hays@gaepd.org 404-363-7115