How Does Biomass Work?
Biomass has many advantages, including the fact that there are many sources of biomass material. Forests, for example, provide much material for biomass. Lumber, paper and pulp mills use forestry waste to power their factories. Whether it’s tree tops or branches that are leftovers from timber operations, these materials are readily available for biomass use.
There is also an abundance of biomass material from urban areas. Think of the construction sites that dot every city. In these sites there are always leftover wood and shipping pallets. These are perfect raw materials for biomass use.
There are also numerous sources for biomass that are just being developed or soon to be realized. As we all know, animal farms produce manure. And the process for converting crops into food leaves waste that also helps in producing biomass. The early ranchers fed a nation with their beef that was driven from Mexico to Kansas. Even now, we are experiencing the impact of those cattle drives. Years ago in Texas, great ranchers like W.T. Waggoner drove cattle all the way from Mexico, up the Chisholm, Western and Goodnight Loving Trails and into Abilene, Kansas. We tend to nostalgically look back at the cattle drives and think they lasted for decades. But with the advent of the railroads, the era of the cattle drives lasted only about 20 years. But parts of trails can still be seen today. The cattle that traveled through Texas, Oklahoma, Missouri and Kansas were carrying a hidden cargo in their stomachs. The seeds of the mesquite tree were dropped in manure all across the south west. This tree had previously been confined to Northern Mexico and deep South Texas. For generations, ranchers have cursed this tree and its development, as the tree consumed a lot of water and often invaded grazing pastures. Texas is listed as having more forestry lands than all states except for Alaska all because of the mesquite tree. The seeds that were planted in just a short amount of time over a hundred years ago are now ready to be harvested and used to fuel biomass.
The state also believes that the thirsty mesquite with its long tap root (up to 150’ deep) is directly to blame for the extensive drop in the Texas water table over the last 50 years. If its cut, the Mesquite Tree quickly grows back. Yet today, the Mesquite has a new purpose. Plans are being made for biomass power plants to use this timber that burns slow and very hot which perfectly fits with the needs for biomass. It’s amazing how the Mesquite Tree has gone from a curse to a blessing in such a short time.
Clearly, the best resource for biomass is wood. How does it work? Essentially, the wood is gathered in large trucks. It is then taken to a biomass plant. This is where the wood is converted into biomass. The wood goes into the combustion process. Combustion allows for the biomass fuel to then be converted into hot air, hot water, steam and electricity.
Perhaps the most common form of combustion is the furnace. When the biomass heats up in the furnace, it transforms into heat energy. Another form is the boiler. In this case, the combustion heat is converted into steam. Steam can then be use for heat, mechanical energy or electricity.
That’s it. It’s that simple. It’s that revolutionary.
Chemical composition of biomass
Biomass is carbon based and is composed of a mixture of organic molecules containing hydrogen, usually including atoms of oxygen, often nitrogen and also small quantities of other atoms, including alkali, alkaline earth and heavy metals.
In plant material the carbon used to construct biomass is absorbed from the atmosphere as carbon dioxide (CO2) by plant life, using energy from the sun. Plants may subsequently be eaten by animals and thus converted into animal biomass (like manure). However the primary absorption is performed by plants. If plant material is not eaten it is generally either broken down by microorganisms or burned:
- If broken down it releases the carbon back to the atmosphere, mainly as either carbon dioxide (CO2) or methane (CH4), depending upon the conditions and processes involved.
- If burned the carbon is returned to the atmosphere as CO2.
Both of these processes have going on for as long as there have been plants on Earth and this is what is called the “Carbon Cycle”
