According to the EIA’s latest Manufacturing Energy Consumption Survey (MECS), waste fuel accounted for 29% of US manufacturing fuel used in 2010. Commonly, waste fuels are byproducts of onsite production processes but most have little or no economic value. In 2010 however, waste fuels accounted for 4160 trillion Btu and were used in a wide variety of manufacturing industries.
Waste fuels are usually used in situ because they are readily available to use for manufacturing heat and power. Most such fuels are mainly derived from the onsite production process and cost little or nothing to use, lowering overall costs. Using solid waste fuels also decreases the volume of waste disposal needed, lowering disposal cost for manufacturers.
Usually, the industries producing the highest volumes of vales fuels are energy intensive and can readily use them, and doing so is less expensive than marketing and transporting them to a buyer. However, there are waste fuels such as pet coke, that producing industries cannot make use of, while others can. Pet coke is produced by refineries as a waste product and is sold to cement plants and paper mills to be used as a fuel and to aluminium smelting plants for anodes.
Where the waste fuels go
The petroleum and coal products industry uses waste fuel for most of its fuel consumption. Also, the paper and wood products industries use available biomass products from trees and production derivatives like black liquor. Chemical facilities also use waste gas. The Iron and steel industries use mostly blast furnace gas, a smaller but still important source.
Waste gas is the most voluminous waste fuel and comes primarily from petroleum and coal products. Small quantities of waste gases are found in food and beverage manufacturing. In the refining industry, waste gas is known as still gas, which is a mixture of refined hydrocarbons such as ethane, propane and normal butane, among others. The petroleum and coal products industry uses waste fuels for 59% of its fuel use. Blast furnace and coke oven gases are connected to the iron and steel industry, which uses waste fuels for 23% of its fuel use. The heat from blast furnaces and coke oven gas is sometimes uses to generate electricity in a combined heat and power (CHP) plant.
Biomass is another large class of waste fuel and is used principally in the paper and wood products industries. The paper industry uses waste fuel for 58% of all its fuel needs.
Waste material used as fuels is very diverse. Wood and paper industries, chemicals, petroleum and coal products, plastics and cement. Waste material are waste oils and tars, waste paper, and anything else that can be used to provide heat and power in an industrial facility, e.g. the cement industry uses a variety of delivered waste materials to provide heat for its kilns. Because of the inconsistent quality and heat content of waste products, they cannot be used for more than 10 – 30% of a cement kiln’s heat output.
Adapted from press release by Claira Lloyd
Read the article online at: https://www.energyglobal.com/downstream/gas-processing/25102013/waste_fuels_for_manufacturing/