Fuel from the Field to the Flue: Grass fueled heating equipment combustion optimization project.

By Christopher W. Davis

VERMONT NRCS CONSERVATION INNOVATION GRANTFinal Project Report – March 24, 2017

The Project� Review research on grass biomass that show promise as a boiler fuel.

� Review available production heating equipment in the 100,000 – 500,000 BTU/Hour size that have features that could handle challenges of grass biomass combustion.

� Purchase and install the selected boiler in a building at MCF (Evoworld HC 100 Eco hot water boiler rated at 350,000 BTU/Hour).

� Harvest and densify variety of grass biomass and grass & wood blends into1/4” diameter pellets and 2” diameter “pucks”.

� Run controlled test burns in the Evoworld boiler with these biomass fuel samples.

� Record combustion data, make adjustments to and optimize the boiler performance during the testing.

� Lab test results for the fuel samples and the mineral content of the ash.

� Publish the findings, hold open houses and create a website.

� Make recommendations for changes to the Evoworld boiler to improve its performance with grass biomass fuels.

� Continue to test grass biomass fuels in the boiler.

How did we do it....

� Grass plots by UVM/Vt. Sustainable Jobs Fund.

� Cut and baled the grasses (60# square bales or 500# round bales).

� Found people to densify the grasses (Enviro Energy and Adam Dantzscher).

� Found and installed an Evoworld boiler that could burn grass biomass fuel.

� Developed testing methods.

� Used a portable combustion analyzer (Wohler A500 and Smoke Test Pump).

� Learned how to optimize the combustion.

� Recorded the results.

� Produced a final report.

Design Features needed for successful grass fuel combustion

� Device can handle1/4” pellet or larger “puck” sized fuel.

� Control software/hardware with a broad range of adjustments.

� Temperature control

� Air volume

� Fuel feed

� Oxygen level in flue gas

� Draft pressure

� Can handle high ash volumes (1-8%).

� Can clear clinkers, if they form.

� Stainless steel components in contact with:

� Combustion by-products (ash, flue gasses)

� Grate

� Turbulators

� Flue

� Manufacturer willing to participate or allow these fuels in their boiler.

� Conformance with EPA regulations?

� Impact on the warranty?

Fuel enters here

Flue gas path

Ash removal path

Evoworld HC 100 Eco Boiler Features

Induced Draft fan

Secondary air

Primary air

O2 Sensor

1stPass

2nd

Pass3rd

PassTube & ash cleaningmotor & gears

Evoworld HC 100 boiler combustion chamber

Pellet Fuel Bin

Puck or Chip Fuel Bin

Evoworld HC 100 Boiler

Meach Cove Farms Boiler and Fuel Storage Layout

Meach Cove Farms

boiler room with water circulation pathways shown

Meach Cove switchgrass 500 – 600 Lb. bales

“Ag Biomass” weedy mulch hay sample

Enviro Energy Pellet Manufacturing Facility

Air dryer

PelletMill

MixingBin

Dry PelletStorage Bin

Bag scale & sealer

Adam Dantzscher explaining the BHS SluggerDensifying machine, 2” diameter pucks in production

Tractor PTO Provides power

Heated die

Air drying racks

Chopped biomass fuel ready to feed into the unit

Bagged 2” diameter pucks in storage

Evoworld chipFeed auger

Sweep arm

Meach Cove chip or puck storage bin and fuel loading auger

Evoworld chip feeder – 2” diameter pucks entering handoff box

1/4” pellet feed auger

Back up EK-2 oil boiler

EvoworldHC 100 Eco Boiler

Firebox cleaning tools

2” diameter pucks burning with boiler door open

Typical flue gas emission test set up

Moisture Free GCV data taken from Twin Ports Testing Analytic test reports; arrival dates 2/22/2010 (VT Wood & Mulch pellets), 1/31/2012 (rest of pellets) & 11/30/2015 (2” pucks)

Smoke # Scale: The higher the smoke number, the darker the stain on the filter paper. (0 = No smoke detected; 9 = Solid black).

Chlorine data taken from Twin Ports Testing Analytical test report 1/31/2012Did not test VT Wood pellets in Oct-Nov 2015 Combustion test

Findings

Findings-continued

Findings – continued� The Evoworld HC 100 worked very well.

� Could handle both fuel sizes

� Easy to adjust fuel and air feed rates

� Could monitor temp., O2, and pressure and self-adjust

� Could handle the ash volume & clinker

� Good efficiency 56% - 81% for grasses and blends tested

71%-82% for wood pellets tested

� Ag. Biomass sample the biggest surprise.

� 81.5% efficiency during burn (better than most wood pellet samples)

� Better than other grasses tested

� CO levels lower than wood pellets tested

� NO higher

� Chlorine lower than all grasses

� Smoke test better than wood pellets, similar to other grasses

� Giant Miscanthus performed better than other grass samples.

� 77% efficiency, lowest CO, 2nd lowest NO

� Among the lowest smoke test

Findings – continued� 2” diameter pucks burned better than pellets – caused fewer issues.

� Samples with wood content had higher ash fusion temperatures.

� Clinker formation issues with pellets.

Problems encountered

� Fuel residue & clinkers blocked primary air – we have a mechanical solution for this.

� Clinker formation with grass pellets – combustion temp range and chemical composition are factors to mitigate this.

� Chlorine content varied with all samples.

� Wood 27 - 102 ppm

� Ag. Biomass 227 ppm

� Miscanthus 352 ppm

� Switchgrass 973 - 2,517 ppm

� Mulch Hay 2,146 - 3,703 ppm

� Possible corrosion of turbulators due to flue gases – need to research

� Finding someone to densify biomass is a limiting factor to adoption.

ConclusionsWhy we should do this....

� Fuel cost $/million BTU competitive with wood pellets and chips.

� Efficiency of combustion competitive with wood pellets.

� Emissions comparable to wood pellets.

� Available range of grass biomass fuel.

� Grows everywhere.

� Locally available fuel - $$ circulate locally.

� Best suited for farm, light industrial, institutions and central heating plant operators.

� Non-productive Ag. Land and field buffer areas = fuel source.

� Water quality benefits – perennial crop, buffer areas, reduces runoff.

� A U.S.-made production boiler is available (ASME, UL certified).

Acknowledgements

Special thanks to....

� Sid Bosworth, Agronomist, UVM Extension Service.

� Christopher Callahan, Agricultural Engineer, UVM Extension Service.

� Bob Kort, CIG Program Manager, Energy Coordinator, USDA NRCS.

� Meach Cove Farms Directors.

� Meach Cove Farms Staff.� Barbara Mercure� Jack McGuire� Gary Marshall� Jessie Addis� Denny DeCoff� Richard Lawrence

� Gerry & Betty Guillemette.

� Adam Dantzscher.

� Lou Okonski, President Troy Boiler Works and Evoworld USA.

� Dr. Jerry Cherney, Dept. of Crop and Soil Sciences, Cornell University, Ithaca, NY.

� Michael Newtown, PE, Associate Professor & Dean, Casino School of Engineering Technology, SUNY Canton, NY.

� Bob Miller, founder, Enviro Energy, Wells Bridge, NY.

� Gus Swanson and Jim Trussler, LST Energy, Nova Scotia, Canada.

References

Bosworth, S., Kelly, T., (2015, February). Evaluation of Warm Season Grasses for Biomass Potential in Vermont 2009-2012, Revised. University of Vermont Extension Service. Retrieved from https://pss.uvm.edu/vtcrops/articles/EnergyCrops/Vermont_WSG_Biomass_Report4.2013revised.pdf

Bosworth, S. (2014). Biomass Production on “Marginal” Land in Vermont, University ofVermont Extension Service. Retrieved from http://pss.uvm.edu/grassenergy/ArticlesPotential_Biomass_of_Existing_Marginal_Land.pdf

Callahan, C.W. (2016). An Update on Solid Grass Biomass Fuels in Vermont.Bennington, VT: UVM Extension, with funding from The Vermont Bioenergy Initiative.Retrieved from blog.uvm.edu/cwcallah/files/2016/05/Summary-Report--Grass-Puck-Testing-at-Meach-Cove-2015-Final-2016-04-18.pdf

Dutta, A., (2010, April). Project EPP 09-001: Assessment of the Atlantic hay pellet boiler – Final Report, Nova Scotia Department of Agriculture, Truro, NS, Canada. Retrieved from http://www.meachcovefarms.org/images/Grass_pellet_combustion_Final_report,_Nova_Scotia_Ag_College,_4-23-10.pdf

Falchek, D., (2016, October). Pellet Plant relocated to Moscow, NY, The Times Tribune, Retrieved from http://www.thetimes-tribune.com/news/pellet-plant-relocated-tp-moscow-1.2105738 Follow-up on the Enviro Energy pellet plant.

Helmers, M., Isenhart, T, Dosskey, M., Dabney, S.,Strock, J., (2006, US EPA). Buffer and Vegetative Filter Strips. Retrieved from https://www.epa.gov/sites/production/files/2015-07/documents/2006_8_24_msbasin_symposia_ia_session4-2.pdf

References-continued

Kiraly, M., (2014). Grass BioEnergy Feasibility Study 2008-2012, Catskill Watershed Corporation, Cornell Cooperative Extension of Delaware County, NY. Retrieved from http://www.cwconline.org/linked/grass_bio-energy_feasibility_study.pdf

Kotrba, R. (2015, December). The Untold Upside of Low Oil Prices. Retrieved from biomassmagazine.com/articles/12691/the-untold-upside-of-low-oil-prices

Metz, G. (2015, May). Description of the Enviro Energy, LLC biomass pellet manufacturing facility, Cornell Cooperative Extension, Tompkins County, NY.Retrieved from ccetompkins.org/energy/renewable-energy/biomass/envior-energy-llc

Sherman, A. (2011, January). A Technical Assessment of Grass Pellets as Boiler Fuel in Vermont. VSJF. Retrieved from http://www.biomasscenter.org/images/stories/grasspelletrpt_0111.pdf

Stutter, M, Chardon, W., Kronvang, B., (2012, March). Riparian Buffer Strips as a Multifunctional Management Tool in Agricultural Landscapes: Introduction. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/22370391

http://www.meachcovefarms.org

http://www.twinportstesting.com/ Description of the laboratory, their chain of custody procedures, certification standards (ISO, EN, ASTM).

pss.uvm.edu/grass energy/ Grass energy related reports, field studies by UVM and others.

Wilson Engineering, (2014, May). Grass Energy in Vermont and the Northeast: State of the Science and Technology. Vermont Sustainable Jobs Fund. Retrieved fromhttp://vermontbioenergy.com/wp-content/uploads/2013/03/Grass-Energy-in-Vermont-and-the-Northeast.pdf