Biofuels And Food Production Flashcards
What are the two types of biogas generators?
Batch generator and continuous generator.
Why can’t biogas be stored as a liquid?
Because biogas needs to high a pressure so it has to be used straight away.
What conditions do you need for a biogas generator?
Warm and anaerobic (no oxygen) conditions.
What would happen to a biogas generator if the conditions were not anaerobic?
The certain bacteria would not be able to grow so it wouldn’t produce biogas.
Meaning anaerobic fermentation can not take place.
What are the main gases found in biogas?
Methane (70%) Carbon dioxide (30%)
Why is methane the more important gas produced from biogas?
As it can be burnt so we can use it for cooking, heating, electricity production.
What type of reaction happens in a biogas generator?
Exothermic reaction, gives off heat
Why does it take some time before a biogas generator produces methane?
Because there will still be some oxygen in it at the start so the aerobic reaction takes place first producing carbon dioxide but when the oxygen gets used up methane levels will start raising.
What economic and environmental effects do biogas generators have?
It is a carbon neutral process, the carbon released was taken in by the plants which lived recently.
Burning methane as a biogas means it’s not released into the atmosphere.
Biogas generators act as a waste disposal system, so the waste is not left to cause disease or pollute water supplies.
The raw material is cheap and readily available.
The digested material is a good fertiliser so people can grow more crops.
What goes into a biogas generator?
Plant, animal and food waste
What can improve the efficiency of food production? (In general)
Reducing the number of stages in the food chain
Restricting the energy lost by farm animals
Developing new food sources (such as mycoprotein)
How is energy lost by farm animals?
Energy is lost through: Movement Heat (regulating body temp) Excretion Growth
What happens as the number of stages in a food chain increase?
Every time you move up a stage in a food chain there’s less energy and less biomass.
What are the advantages of food made from microorganisms?
In some developing countries it is hard to find enough protein.
Growing mycoprotein in a fermenter is an efficient way of producing protein for people.
Microorganisms grow very quickly and don’t need much space.
Microorganisms can feed on waste that feeding animals would not.
What fishing regulations are there to maintain fish stocks in the ocean?
Net size (not to big) Quotas (limits on the number of fish that can be caught) Avoid fishing during mating season Avoid breeding grounds Mesh size (reduce the number of unwanted/younger fish being caught)
