26.11.2012 Views

Wood-Chip Heating Systems - Biomass Energy Resource Center

Wood-Chip Heating Systems - Biomass Energy Resource Center

Wood-Chip Heating Systems - Biomass Energy Resource Center

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

WOOD CHIP HEATING SYSTEMS<br />

12<br />

the municipal solid waste stream, such as construction<br />

and demolition wood, because it is not likely to<br />

be readily available for purchase and may not be<br />

acceptable to air quality regulators.<br />

Although a common perception of wood fuel may<br />

be that it is dirty and hard work to handle, that view<br />

is not accurate for the automated biomass systems<br />

considered in this guide. Modern, fully automated<br />

biomass energy systems involve no manual fuel<br />

handling, and semi-automated systems require<br />

minimal operator involvement. The fuel is stored out<br />

of sight in enclosed bins, and the combustion process<br />

is more effi cient and clean-burning than the modern<br />

wood stove. (Chapter Ten discusses in detail the issues<br />

of public perception and public education in biomass<br />

burning.)<br />

What Does a <strong>Wood</strong>-<strong>Chip</strong> System Look Like?<br />

<strong>Biomass</strong> heating plants are similar in their<br />

functional parts to heating plants that run on conventional<br />

fuels. They include large-volume fuel storage<br />

capability, a means of moving the fuel from the storage<br />

bin to the burner, a burner and boiler to burn the fuel<br />

and extract the useable heat from combustion, and<br />

connection to a chimney that disperses the combustion<br />

gases. Boiler rooms or boiler houses for biomass<br />

systems are usually larger than conventional boiler<br />

rooms, because wood boilers are larger and the fuelhandling<br />

equipment takes up extra space. The chimney<br />

of a biomass system is usually taller than that for an oil<br />

or gas system.<br />

From the outside, a biomass system looks much like<br />

a conventional boiler facility, except for its fuel storage<br />

bin. While oil and liquid propane (LP) gas are typically<br />

stored in buried tanks (natural gas requires no on-<br />

site storage), wood-chip bins may be above or below<br />

ground. If the wood-chip bin is below ground, which<br />

is the common case, only its loading doors are visible.<br />

Above-ground bins may look just like farm silos: they<br />

are round concrete or metal silos of varying heights.<br />

In most cases, to the casual observer, biomass energy<br />

systems in the 1-10 MMBtu size range do not alter the<br />

outer appearance of the facility. They fi t into the look of<br />

the existing buildings and the surrounding locale. When<br />

operated properly, they do not produce visible smoke.<br />

However, because the biomass fuel usually burned is<br />

green, or close to one-half water, in cold weather the<br />

chimney may show a plume of condensed water vapor.<br />

Interviews with dozens of system operators support the<br />

conclusion that odor generated by the fuel or the smoke is<br />

almost never a problem.<br />

Many of the photographs in this book were selected<br />

to show how the biomass heating plant fi ts into the<br />

overall appearance of a facility.<br />

Interviews with system owners indicate that truck<br />

traffi c for institutional biomass systems is not a<br />

signifi cant issue. Just as a large oil-burning facility will<br />

receive fuel deliveries from large tanker trucks, chip<br />

systems get fuel delivered in tractor trailers. It takes<br />

fi ve to six chip deliveries to equal one 7,500-gallon oil<br />

tanker load. As an example, most biomass systems<br />

in schools average from six to 40 deliveries per year.<br />

Truck traffi c for wood-chip deliveries is usually less<br />

frequent than that for other school supplies delivered<br />

by tractor trailer. For other institutional or commercial<br />

facilities that burn biomass, the number of deliveries<br />

may be comparable to or higher than that of schools,<br />

depending on the size of the facility and its heating<br />

requirements.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!