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Archive for the ‘Multi-fuel capabilities’ Category

Harmon P68 fired with Grass at the Ashoken Center

There have been several requests for me to explain our experiences burning grass pellets in the appliances being used the Catskill Grass Bio-Energy project.

(Please note:  any mention of brand names is for informational purposes only, and is not intended as an endorsement of a particular product.)

Our first purchases were two Quadrafire Mt. Vernon pellet stoves. One was quickly installed and the other put in storage for later installation. We also purchased two Central Boiler Maxim pellet hydronic furnaces. One was sited at the Town of Franklin NY Town Garage where the first Quadrafire was installed in the Town meeting hall in the same building. We were able to secure the services of a local plumber who completed the installation by the end of December that first year.

Initial operation of these first units had a steep learning curve. The Maxim furnace burned well after the operator at that site tried many combinations  of feed rates and blower settings. Neither the manufacture nor the local dealer were of little help tailoring the settings to burn grass. Luckily the operator at the site had a lot of experience in the heating industry and had interest in making the unit work to its potential. As the season grew colder we found that if the unit was pushed to produce maximum heat it had a tendency to melt the aeration paddle on the end of the feed auger. The original was mild steel but the replacements were made of stainless steel. They did last longer but eventually failed as well. We kept replacements on site after the third failure. Another shortcoming of this unit is the size and position of the ash drop. Ash has to be removed by scooping the ash out daily also the unit has to be shut down weekly to clean the interior of the burn area and the heat exchanger. If this is neglected the unit pushes smoke back into the hopper on top of the furnace leaving a creosote type of condensate in the hopper. Another problem with the design of this unit caused two burn backs into the top hopper. We are not sure the reason for the first but the second was the result of a power outage lasting six hours. The unit needs a supplemental power source to run a clean-out cycle if high heat is experienced or a power outage is experienced. By the way, the unit was burning wood pellets at the time of the power outage.

As to the Quadrafire at this site, the operator tried all season to burn grass with little success. Any of the settings on the control unit did not dump the ash fast enough and the fire was snuffed out. We purchased these stoves based upon the success of Dr. Cherney at Cornell University. We knew we needed specific tables to burn grass successfully. Dr. Cherney supplied us with the tables that the manufacture had supplied. We were unable to install the grass tables. We sought help from several Quadrafire dealers and the manufacture and were told multiple times that Quadrafire does not support burning grass pellets even though we knew grass tables existed. After that initial season we pulled the unit and replaced it with a Harman P68 which has been burning well ever since. The Harman has analog controls for feed rate and also has a unique burn system where the pellets are pushed up a burn ramp and the ash is pushed off the ramp into a very ample and removable ash pan.

We have four Harman stoves on site at this time, Two P68s and two P45s. These units are working well burning grass pellets, but, like all appliances burning grass, they require frequent cleaning. Anyone wishing to burn grass with  appliances that are not specifically designed to handle grass will need the owner/operator to be conscientious about operation and cleaning.

More about the Quadrafire saga (we are using them satisfactorily)  and our other appliances and installations next time.

Keep Warm!



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Second post from St Lawrence County:   Small to Large Institutions as Biomass Fuel Consumers

People have been using grass as a fuel for centuries, but today its promise as a fuel that can successfully compete with fossil fuels remains unfulfilled. Yes, there are systems that can very efficiently combust baled grass, such as, for example, REKA Boilers that are marketed by Skanden Energy, but these systems are not yet widely in use in the United States. There are also other multi-fuel biomass boiler manufacturers that can accept densified grass fuels, such as Hurst Boilers and Advanced Recycling. These are aimed at institutional-sized applications. There are a few choices for residential-sized biomass heating equipment, but the ability to reliably burn grass pellets or briquettes has not been emphasized when marketing and certifying these units.

Until manufacturers of residential biomass heating systems promote the use of grass fuel, the market for producing pellets or briquettes will remain stunted. Of course, manufacturers don’t want to sell true multi-fuel heating units unless they are certain that people really want to burn something in them other than wood pellets or corn. Likewise, growers and producers are not going to make the necessary investments in grass production and densification until people start using and demanding the fuels. Chicken and egg.

At this point in time it would seem that in order to develop the supply side of the grass energy equation we need some major consumers. The most realistic consumers would be the larger institutional users such as school districts, hospitals, combined heat and power installations, etc. If enough of these consumers installed multi-fuel boilers, it is likely that grass could be competitive with, say wood chips. Farmers would have a reasonable assurance of a saleable crop and producers would make the investment in densification equipment. Once the production side is up and running, hopefully the residential market could then be more easily developed.

So far we have one school district in St. Lawrence County – Edwards-Knox Central School – who has installed a Hurst Boiler and is currently using wood chips. They have the capability to receive, store and feed pellets less than 2 inches by 2 inches. They could also burn corn. The St. Lawrence County Grass Energy Working Group and the Drum Country Bio Energy Group have been encouraging other school districts, hospitals and businesses to make use of feasibility studies that were available on a completive basis and 100% funded though the U.S. Forest Service. The Forest Service is interested in promoting wood fuels, but we have also been advocating that any entity considering biomass heat specify a system that has multi-fuel capability. Recently, some 11 school districts, hospitals and businesses in St. Lawrence, Jefferson, Franklin and Lewis Counties were awarded feasibility studies, performed by Yellow Wood Associates, Inc.:

Brasher Falls Central School District
Burrows Paper
FiberMark
Potsdam Central School
Salmon River Central School
Colton-Pierrepont Central School
Lewis County Social Services and Public Safety Buildings
Watertown Industrial Center Local Development Corporation
Clifton-Fine Hospital
Clifton-Fine Central School
UH Cedars Complex

Most of these studies are nearing completion as of this date and follow-up site visits are planned for early 2011. We are hopeful that many of these projects will move beyond the feasibility study phase. Stay tuned.

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