1.9 Biomass Flashcards
Explain the term Biomass;
Biomass is a general term for material derived from plants or animals.
Biomass is a general term for material derived from plants or animal manure.
Material that is derived from growing plants or animal manure
Biomass can be used as a fuel. Explain what is meant by the term biomass.
Biomass is material derived from growing plants or from animal manure.
Identify another category of biomass apart from woodchip.
*Organic materials.
* Agricultural crops.
* Agricultural and municipal wastes.
Wood is one example of biomass that can be used as a fuel source. Most of the energy obtained from biomass is through combustion.
(i): Define the term biomass.
(ii): State another categorised type of biomass, part from woo
(i)Biomass is material derived from growing plants or from animal manure. (ii): Any one from: organic materials
agricultural crops
Identify two crops that are commercially grown to produce biomass
Willow
Poplar
Elephant grass
Maize
Sugar cane
Give an example of a crop that can be commercially grown to produce biomass.
Willow / poplar / elephant grass / maize / sugar cane.
Briefly describe the global debate that surrounds farmers growing crops for energy.
Answer to outline the global debate around ‘food versus fuel’.
Global population increasing at a dramatic rate. This is increasing demand for food for basic human survival. Should farm land be used to grow energy crops instead of food produce
Identify two different advantages of replacing coal with biomass at this power station.
Biomass fuel is a renewable energy source / can be replaced in a human lifetime whereas coal takes millions of years to form / cannot be replaced in a human lifetime.
• Combustion of biomass contributes much less to atmospheric carbon dioxide levels (than coal / fossil fuels) / is carbon neutral / does not contribute (as much) to global warming.
State one disadvantage of converting all six units to burn biomass instead of coal
Biomass is more expensive to use compared to coal.
• Biomass is less efficient compared to fossil fuels.
• Biomass requires more land for production.
Biomass is another alternative to fossil fuels.
(i): State two advantages of using biomass as an alternative to fossil fuels.
(ii): State two disadvantages of using biomass as an alternative to fossil fuels.
Any two from:
Lower fossil fuel dependency
Renewable
Lower greenhouse gas emissions
Waste may be diverted from landfill
(ii): Any two from:
Requires significant quantities of land
Has a lower energy density than fossil fuels/larger quantities required Biomass power plants have higher set-up costs.
All relevant,sponses will be given credit.
State the typical (%) of energy from combustion that is obtained from biomass.
% in the range of 90%
State the main process used to obtain energy from biomass.
Combustion / burning.
Explain the term energy density
Energy density is the amount of energy stored in a given system or region or space per unit volume or mass
State two properties which could be compared and contrasted when assessing different types of woodchip for use as biomass fuel.
Moisture content.
• Porosity,
• Bulk density
• Energy density
Woodchip is a form of biomass that can be commercially produced. Explain the effect of moisture content on one property of woodchip
fuels.
Higher moisture content results in woodchip with lower energy density. As energy must be used to evaporate the water before combustion occurs.
Woodchip is a specific example of a commercially available biomass from the wood category.
List two properties of woodchip which are important in determining its effectiveness as a fuel.
1.
2.
*Percentage moisture content
* Calorific value / energy density
* Particle size
Outline the process of gasification in relation to biomass.
Gasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen and carbon dioxide.
This is achieved by reacting the material at high temperatures, without combustion, with a controlled amount of oxygen and / or steam to produce syngas.
Describe the process of gasification of biomass.
Biomass is converted into a mixture of carbon monoxide And hydrogen Commonly known as syngas.
Biomass can be converted into syngas.
Name the two main gases present in syngas
*Carbon monoxide
*Hydrogen
(i)Biomass can be used to produce a mixture of carbon monoxide and hydrogen gas.
(ii): Explain how biomass is converted into carbon monoxide and hydrogen.
(i) Syngas
(ii): Biomass is heated in the presence of oxygen and steam. This causes the biomass to break down into a mixture of carbon monoxide and hydrogen gas. This process is called gasification
State three applications in which the main product of the gasification of biomass can be utilised.
Used in the production of ammonia.
• Used in the production of methanol.
• Used as an intermediate in producing synthetic petroleum.
• Or can be used as lubricant in chemical processes.
• Syngas is combustible and often used as a fuel of internal combustion engines.
Certain types of biomass can undergo anaerobic digestion. Describe the process of anaerobic digestion
Anaerobic digestion is a biological process that results in the breakdown of organic matter by naturally occurring bacteria in an environment that has an absence of oxygen.
Biogas is a mixture of gases produced by the anaerobic digestion of certain types of biomass.
(i) Define the term anaerobic digestion.
(ii) List the two main gases that are present in biogas
(i) The biological breakdown of organic matter in the absence of oxygen
(ii) Methane and Carbon dioxide
Name the main product of anaerobic digestion and state its use.
Product. Use.
Product – Methane or biogas.
Use – Fuel or electricity generation.
