It is a term that has been increasingly heard in recent years and although it is not something really new, there are many people who are not clear about its concept. Biomass is renewable organic material that comes from living things, both plants and animals. As surprising as it may seem at first, biomass was the most important source of energy consumption in the United States until the 1960s.
Today it is still an important fuel in many countries, highlighting its presence in less favored countries where its use in homes is significant. In addition, the use of biomass fuels for transport and electricity generation is increasing in many developed countries as a means of avoiding carbon dioxide emissions from the use of fossil fuels. It is estimated that before the Covid-19 pandemic hit, about 5% of total primary energy use in the United States came from biomass.
The five most important biomass plants in the world are in Europe, three of them in Finland, one in the United Kingdom and the fifth in Poland.
Biomass sources for energy
Biomass energy is a sustainable and renewable and sustainable energy source derived from organic matter, and can be used to generate electricity. Common materials used to develop biomass fuel are as follows:
-Wood waste and processing: firewood, wood pellets and wood chips, sawdust and waste from wood and furniture factories, and black liquor from pulp and paper factories.
-Agricultural crops and waste materials: corn, soybeans, sugar cane, woody plants, algae, and food and crop processing residues.
-Biogenic materials from municipal solid waste: paper, cotton and wool products, and food waste.
-Animal manure and wastewater produced by humans.
Conversion of biomass into energy
Biomass is converted into energy through various processes, including direct combustion to produce heat, thermochemical conversion to produce solid, gaseous, and liquid fuels, chemical conversion to produce liquid fuels, and biological conversion to produce liquid and gaseous fuels. .
Direct combustion is the most common method of converting biomass into useful energy. All biomass can be burned directly to heat buildings and water, to heat industrial processes, and to generate electricity in steam turbines.
The thermochemical conversion of biomass includes pyrolysis and gasification. Both are thermal decomposition processes in which biomass feedstocks are heated in pressurized closed vessels called gasifiers at high temperatures. They differ mainly in the process temperatures and the amount of oxygen present during the conversion process.
Pyrolysis involves heating organic materials to temperatures between 400 and 500 ° C in the almost complete absence of free oxygen. Biomass pyrolysis produces fuels such as charcoal, bio-oil, renewable diesel, methane, and hydrogen.
Hydrotreating is used to process bio-oil (produced by rapid pyrolysis) with hydrogen at elevated temperatures and pressures in the presence of a catalyst to produce renewable diesel, renewable gasoline, and renewable jet fuel.
Gasification involves heating organic materials to temperatures between 800 and 900º C with injections of controlled amounts of free oxygen and / or steam into the container to produce a gas rich in carbon monoxide and hydrogen called synthesis gas or syngas. Syngas can be used as a fuel for diesel engines, for heating and to generate electricity in gas turbines. It can also be treated to separate hydrogen from gas, and hydrogen can be burned or used in fuel cells. Syngas can be further processed to produce liquid fuels using the Fischer-Tropsch process.
A chemical conversion process known as transesterification is used to convert vegetable oils, animal fats, and fats into fatty acid methyl esters (FAME), which are used to produce biodiesel.
Biological conversion includes fermentation to convert biomass to ethanol and anaerobic digestion to produce renewable natural gas. Ethanol is used as a fuel for vehicles. Renewable natural gas, also called biogas or biomethane, is produced in anaerobic digesters in wastewater treatment plants and in dairy and livestock operations. It is also formed and can be captured in solid waste landfills. Properly treated renewable natural gas has the same uses as fossil fuel natural gas.
Finally, it should be noted that there is a lot of room for improvement and growth in the area of biomass, as researchers are working on ways to improve these methods and develop other ways to convert and use more biomass for energy.