L1 Flashcards
1
Q
Key contributors to GHG emissions in NZ
A
- Road transport
- Chemical industry
- Food processing
- Livestock digestive systems
- Agricultural soil
- Industrial and household refrigeration and air conditioning systems
2
Q
Renewable resources and organic wastes
A
- Woody biomass including wood residues
- Biomass from agricultural residues
- Organic wastes (green bin, paper wastes, sewage sludge)
- Ethanol from corn and sugarcanes (renewable but competing with foods)
- Sewage sludge from wastewater treatment
3
Q
Syngas from gasification and pyrolysis
A
- Synthetic gas
- Ideally a mixture of H2 and CO only. Realistically will contain CO2 and CH4
- Produced from natural gas, coal, biomass by reaction with steam and oxygen
- Used as intermediate resource for production of hydrogen, ammonia, methanol
4
Q
Natural gas
A
- Mainly comprised of CH4 but contains alkanes and CO2
- Fossil fuel
- Used as energy source and plastic/chemical production
5
Q
Synthetic natural gas (SNG)
A
- Fuel gas produced from fossil fuels such as coal and oil or from biomass
- Also produced from renewable electricity (electrolysis to generate H2, then reacts with CO2 to produce CH4 and water)
6
Q
Biogas
A
- A gas mixture comprising mainly CH4 but also CO, CO4, H2, H2S
- Produced from the breakdown of organic materials from bioprocesses (e.g anaerobic digestion)
- Mainly used for energy (combustion)
7
Q
Hydrogen
A
- Clean energy carrier (No carbon, only water upon combustion)
- Produced by heating natural gas with steam to form mixture of CO and H2 which is then separated.
- More expensive than other fuel gases
- Density is low
8
Q
Liquid biofuels
A
- Liquid biofuel from biomass
- — Fischer-Tropsch liquid
- — Pyrolysis liquid
- Liquid biofuel from corn
- Liquid biofuel from sugar cane
- Liquid biofuel from oil seeds
9
Q
Lower heating value
A
- Calorific value
- Heat released from combustion of a carbonaceous fuel when the product water is in vapour state
- Pine: 19 MJ/kg dry
10
Q
High heating value
A
- Gross calorific value
- Heat released from combustion of a carbonaceous fuel when the product water is in liquid state
- Pine 21 MJ/kg dry
