Biofuels

Question 1

What is fermentation?

Answer 1

When bacteria or yeast break sugars down by anaerobic respiration.

Question 2

How does yeast make ethanol?

Answer 2

The break down of glucose by anaerobic respiration.

Question 3

What is the equation for the break down of glucose?

Answer 3

Glucose –> Ethanol + Carbon dioxide + Energy

Question 4

What is the mixture of ethanol and petrol called?

Answer 4

Gasohol.

Question 5

What can be used instead of glucose?

Answer 5

Maize starch (carbohydrase).

Question 6

What is biogas made up of?

Answer 6

70% methane and 30% carbon dioxide.

Question 7

What is used to make biogas on a large scale?

Answer 7

Sludge waste.

Question 8

Why do biogas generators need to be kept at constant temperature?

Answer 8

To allow microogranisms to continue respiring.

Question 9

What are the two types of biogas generators?

Answer 9

Continuous and batch.

Question 10

Why can’t biogas be stored as a liquid?

Answer 10

Needs to high a pressure.

Question 11

What can biogas be used for?

Answer 11

1. Heating
2. Cooking
3. Lighting
4. Power a turbine

Question 12

How do batch generators work?

Answer 12

1. Small batches
2. Manually loaded up
3. By-products cleared away

Question 13

How do continuous generators work?

Answer 13

1. Operate all the time
2. Continuously fed in
3. Biogas produced at steady rate

Question 14

What does a simple biogas generator need?

Answer 14

1. Inlet for waste material
2. Outlet for digested material to be removed
3. Outlet for biogas to be piped out

Question 15

Why are continuous generators better than batch generators?

Answer 15

They’re more convenient, as they don’t have to be loaded, emptied or cleaned.

Question 16

Why are batch generators better than continuous generators?

Answer 16

They’re cheaper because waste doesn’t have to be mechanically pumped in and digested material mechanically removed.

Question 17

What are the conditions required for biogas generators?

Answer 17

1. 35C to be produced quickest
2. Insulated and kept warm
   3, No leaks

Question 18

Where should biogas generators be positioned?

Answer 18

1. Away from homes

2. Near waste source

Question 19

Why are biofuels a greener alternative to fossil fuels?

Answer 19

1. Carbon neutral
2. Not much acid rain
3. Untreated waste gives off methane but biogas burns it

Question 20

Why are biofuels advantageous?

Answer 20

1. Raw material cheap and available
2. Digested material is good fertiliser
3. Women don’t have to collect wood for fuel
4. Waste disposal system