AG Products and Residues
Agricultural products and residues can include a large variety of materials. See the list below for common sources. The United States contains hundreds of millions of tons of agricultural residues. Often left on fields, forests or land-filled, large quantities go to waste each year. There are economic and environmental benefits to utilizing these materials.
Ash
Ash generation is increasing due to use of coal, biomass, and other feedstocks as fuel sources. Consideration of trace elements, leaching, and volatile minerals are necessary for ash systems. Proper handling of ash is vital for environmental impact and regulatory compliance.
Biomass
The use of biomass for power, fuel and chemicals continues to increase around the world. Biomass is a part of a process called gasification, which works to create synthetic gas or fuel. This process lowers the carbon intensity compared to traditional processes. Biomass can be sources from waste materials, wood, grass, or other organic materials. Properties vary depending on the type of biomass used. There are no set standards for biomass handling.
Coal and Mineral
Coal is a critical fuel for power generation. Generation of electricity starts by burning coal to heat water, which creates steam. The steam drives turbines which create electricity. Other sources of electricity such as wind and solar, unreliable and hard to store. Coal is abundant and reliable. For increased environmental efficiency, coal and biomass can burn together. Gasification of synthetic gas can also made with coal.
Granular Fertilizer
Granular fertilizers can be natural or synthetic in origin. The small granules decay over time releasing nutrients. the two types of fertilizer are organic and inorganic. Organic fertilizers contain compost, biosolids and manure. Inorganic fertilizers combine nitrogen, potassium, and phosphorous. The fertilizer market is over $150 billion in the United States alone.
Logs
The United States contains over 800 million acres of forest land. About sixty percent is private owned. Various levels of thegovernment own the rest. Timber harvesting is a great economic benefit in wood products, power and fuel. It also has several environmental benefits. Benefits include mitigating forest fires, allows space for new trees, and improving habit for wildlife.
Municipal Solid Waste
Municipal Solid Waste consists of residential and commercial garbage. It can contain metal, wood, plastic, textile, and organic material. The United States is the largest producer of municipal solid waste in the world. The waste is often stored in landfills. Mostofthe material in municipal solid waste is reusable. Metal and glass are recyclable. Paper and plastic have uses in power generation. Food scraps and plant matter are great for fertilizer and compost.
Refuse Derived Fuel
Refuse Derived Fuel (RDF) come from certain components of municipal solid waste. Power generation is a great alternative for these material that would otherwise go to landfill. In combination with coal or biomass, RDF can be a great fuel source. RDF is also used for pyrolysis and fluidized bed systems.
Sludge
Sludge is a semi-solid slurry that is a byproduct of industrial processes. Some common processes that produce slurry are water treatment and sanitation systems. Sludge contains liquid and semi-solid components and often contains contaminants.
Tire Derived Fuel
Tire Derived Fuel (TDF) are tires in shredded form used to supplement tradition fuels. Some combustion devices can use whole tires. About 45% of all discarded tires in the United States become tire derived fuel. This is about 130 million tires per year.
Wood Chips
Wood chips are small to medium sized pieces of wood often derived from wood waste. Creation of chips is by cutting or chipping larger logs or wood pieces. Wood Chips have many uses such as fuel for power generation, mulch, cooking, and composting.
Wood Pellets
Wood Pellets are one of the fastest growing segments of the biomass industry. Pellets are often created from waste feedstocks such as sawdust or wood shavings. Common uses for pellets include residential and commercial heating, electricity generation and cooking. Wood pellets are often considered a renewable energy source.