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Fossil Fuels and their future technologies - Coggle Diagram
Fossil Fuels and their future technologies
Formation of fossil fuels
waterlogged deat organic matter not fully broken down also known as peat
compression of peat forms lignite; an early, more polluting for of coal
the compression can also form black coal which is the oldest, but best coal as it has the highest energy density
gas and oil found in association TOGETHER
Advantages of fossil fuels
easy to store
high energy density means it is easier to transport and can be used for energy intensive activities
e.g used for powering steam engines and in iron and steel making
often found in abundant and local deposits
Features of fossil fuels
chemical energy - east to convert into heat energy
energy density - burning at high temperatures to produce electricity
small mass of fuel used to do a lot of work e.g aviation fuel
finite resource - eventually will be depleted
available resources - large overall quantity of fossil fuels so technologies to exploit them are more developed
political and international trade problems - high demand can drive countries to make political decisions to protect future supplies
economic issues - decisions may be based on the cheapest option
Methods of extraction
coal extracted by DEEP mining is expensive or can be done by OPEN PIT mining, which is cheaper but has greater environmental impact
Crude oil - flows through permeable rock and collects in pores
pipe drilled down, pressure from below forces it to surface
Main uses of fossil fuels
crude oil
domestic and industrial heating when not connected to mains
liquid vehicle fuel
nitrate fertilisers - the Haber process
petrochemicals e.g plastics and pharmaceuticals
natural gas
domestic and industrial heating
electricity generation
coal
iron and steel industry
Environmental impacts of fossil fuels
excess gas and oil on oil rigs is burnt to reduce risk of explosions but in doing so atmospheric pollution is increased
oil spills asphyxiate marine life
seismic surveys for oil deposits can impact navigation e.g by cetaceans
coal burning produces large amounts of ash
methane can be released from the mining of coal
New technologies with fossil fuels
coal
coal gasification
coal that is too deep to be mined can be burned underground to release a mixture of natural gases
if in low oxygen, carbon monoxide is produced
produces hydrocarbons
coal liquefaction
coal converted into liquid hydrocarbons
directly or by using solvents through chemical reactions using the hydrocarbons produces in coal gasification
production of liquid is better than gas because it can be used as vehicle fuel
oil
primary oil recovery = uses natural pressure of water below oil or gas to force oil to the surface
secondary oil recovery = pumps water or natural gas to maintain pressure to push oil out
some CCS schemes pump recovered CO2 underground to increase oil recovery
tertiary oil recovery = uses solvents, steam or bacteria to reduce the VISCOSITY of oil
solvents reduce surface tension of oil so it flows more easily
bacteria partially digest heavy oil to produce lighter oil
directional drilling
many wells from a single platform which means you can drill in locations where you weren't previously able to build a platform
can drill through softer rock and reach smaller reservoirs
subsea production wells (ROVs) = used to carry out surveys and inspect underwater equipment
Hydraulic fracturing/fracking
uses high pressure to open fissures surrounding shale rock
water, sand grains and solvents may be pumped into fissures to increase recovery rate
oil and gas flows easier towards recovery wells
problems
natural gas may enter aquifers
chemicals injected may enter aquifers
toxic metals in rock may become mobile
large volumes of water required
may lead to small earhtquakes
Problems reduced by;
collection and treatment of wastewater
reuse waste water e.g for cooling in industry
restrictions on local fracking sites in sensitive areas
oil shales and tar sands
liquid oil is too thick (viscous) to flow or has solid hydrocarbons
tar sands extracted by excavating (ex-situ) the sand and treating it with hot water to produce liquid oil droplets
in-situ production involves steam/solvents being injected or controlled combustion to produce liquid oil
New technologies
Natural gas
recovery rat typically 80-90% but further improved by enhanced gas recovery
involves injecting CO2 or nitrogen to maintain pressure
Methane hydrate = solid crystals found in locations with cold temperatures under high pressure
methane gas released by; pumping in hot water to melt crystals, depressurisation by drilling into sediments or injecting CO2 to displace methane crystals
PERMAFROST contains methane hydrate
Problems if methane is not captured
methane is 38 times more powerful than CO2 as a greenhouse gas so contributes to global warming and the enhanced greenhouse effect
enhanced greenhouse effect
Carbon Capture and Storage
for LARGE power stations it may be possible to capture CO2 - not realistic for cars
if CO2 captured, use of fossil fuels can be extended
can be used in secondary oil recovery/methane recovery
highly experimental and theoretical at the moment - not fully developed