Lecture 7 Flashcards
Demand of Aviation Kerosene
significant increase in demand
close to half of demand met by imports
Cellulosic ethanol addresses the gasoline market
- U.S gasoline usage: 140 billion gallons/ year
- doesn’t address need for higher energy density fuel
The biodiesel Dilemma
Tryglycerides (TAG) from oilseed crops can’t come close to meeting U.S diesel demand
conversion to biodiesel replaces only 5% of petroleum diesel usage
- Agricultural productivity can’t be diverted from the food supply
- cost of feedstock increasing
- input costs high must compete with high valued food market
Therefore an alternative source of TAG’s are needed
Vegetable oil price
The competition for food crops is driving the prices of vegetable oil up
import costs into biofuel costs much higher if you rely on food based based crops
emerging fuels
Several emerging vehicle fuels are in early stages of development. Each promises benefits in the form of increased energy security, reduced emissions, higher performance, or economic stimulation.
Biobutanol
Biogas
- biobutanol (doesn’t absorb water)
- biogas not an emerging fuel really
- biomass to liquids (people think this is the saviour)
- coals to liquids
- Fischer - Tropsch Diesel
- Gas to liquids
- Hydrogenation-Derived Renewable Diesel
Biobutanol
- biobutanol (doesn’t absorb water)
- larger chain length with a higher energy content, but
- cost of conversion is high.
- Converting ethanol to butanol energy wise is a v hard step.
- It can be done.
- People are trying to get bacteria to produce butanol directly instead of getting it from ethanol first
P -SERIES DIESEL
P-Series is a family of renewable, non-petroleum, liquid fuels that can substitute for gasoline.
- developed by US. government
- can substitute for standard fossil fuel
- not. a single compound a blend of 25
About 35% of P-Series comes from liquid by-products, known as “C5+” or “pentanes-plus”, which are left over when natural gas is processed for transport and marketing. - majority coming from ethanol (corn) 45%
- remaining 20% if MeTHF ester from lignocellulose made as by product of paper manufacturing etc etc.
Dilute acid hydrolysis to P.series process description
- take biomass going in
- hydrolyse the biomass to produce levulenic acid (important feedstock in chemical industry)
- separated out into lignin cake and Tars.
- Tar gets combined with the levulenic acid
- Hydrogenate nto. produce MeTHF to improve the burn ( oxygen content)
- MeTHF banned for being too toxic
P series is clean and affordable??
- end product is, however process introducing meTHF makes it not
- retail price is comparable to that of petrol
- not a bad drop in fuel
- but the disadvantages stopped it taking it off
Hydrogenation derived fuel
- Hydrogenation— catalytic hydrogenation and cracking of vegetable oils- produce a diesel fuel.
- Because it involves the application of hydrogen to the feedstock mix, it is more suited for an operation such as a petroleum refinery which generates hydrogen as part of its regular processes anyway.
- cracking vegetable oil
- Adding hydrogen to it
NExBTL renewable diesel
A renewable diesel developed by Neste Oil.
Can use a flexible mix of both vegetable oils and waste fat from the food industry
Excellent fuel properties that meet the highest requirements of automotive manufacturers
Contributes to a significant reduction in exhaust emissions.
The precise reductions of greenhouse gases depend on the raw materials used in production, but are between 40% to 80% throughout the whole product lifecycle.
Can be used as a blending component in conventional diesel fuel.
Can be produced in large volumes on an industrial scale.
NESTE IS NOT USING PALM OIL
Thermo Chemical processing
BURNING
- BURNING
- High temp, low or high pressure
- dry processing
- fast reactions (seconds- minutes. vs days-weeks)
- PYROLYSIS (HEATING WITHOUT AIR)
- Thermal cracking
- CAN PRODUCES BOTH CHRACOAL AND BIO OIL BUT YOU HAVE TO CHOOSE WHICH YOU WANT TO PRODUCE.
PYROLYSIS- BIOCHAR
thermochemical conversion process. it is characterised but the thermal degradation of a solid fuel with restricted oxygen supply.
It can be used to cover biomass into value added products.
Primary products formed during pyrolysis of biomass - Charcoal
bio- oil
acid
Primary products formed during pyrolysis of biomass
- charcoal
- biooil
- acid
Sasol CTL plants at secunda
-1985
converts coal to liquid in South Africa. It’s huge. South Africa had a lot of coal and was embargoed from a lot of products around the world. it was economic.
