Module 3: BioFuels

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Sustainable Energy Workshop for Science and Technology Teachers (SEWFSTT)

BioFuels

What are BioFuels?• Petroleum – Crude Oil

– Mixture of hydrocarbons• Longest – Paraffin wax• Shortest – Natural gas• Contaminants

– Sulfur, nitrogen, etc.

– High energy density– Liquid or Semi-Solid forms

• BioFuels– General term for a variety of

fuels generated from biomass• Solids: Wood, Coal

• Liquids: Biodiesel, Bioethanol

• Gases: Biogas, Bio-Hydrogen

The Carbon-Neutral BioFuel Cycle

Carbon neutral – omits carbon rich fuels that have been sequestered

BioFuel Types• First Generation (NOW)

– ‘Farmed’ fuels– Biodiesel

• Transesterfication of vegetable oils

– Bioethanol• Fermentation process

– Biogas• Recaptured from landfill

• Second Generation (soon?)– Less resource intensive feedstock– Cellulosic ethanol– Synthetic fuels from gasified

biomass– Micro algae

Liquid Bio-Fuels

• Liquefied Coal

• BioEthanol

• BioDiesel

Cost prohibitive

Not carbon-neutral

Policy – Politics Energy Chain

Petroleum Issues• Discharge to Environment

• Resource Availability

• Combustion– Pollution: By-products of combustion

» CO, CO2, NOx, SOx ---- and more!

• Carbon-neutrality

South Korean oil spill (2008)

NOx concentrations over Europe

Construction of a refinery run-off barrier

Ground level Ozone

Energy Generation - Combustion

Combustion includes thermal, hydrodynamic, and chemical processes

BioEthanol

• Gasoline substitute favored by US

• Produced by sugar fermentation• Clear, colorless liquid

• High octane: increased engine efficiency & performance

• Lower energy content than gasoline

– More fuel needed to travel equal distances

• Can be produced from a number of fuel sources– Corn, waste straw, willow and poplar trees– Future Goal: municipal solid waste, algal production

OHHCalcoholethylEthanol 52)(

How can it be high octane if

octane is

CH3(CH2)6CH3

Ethanol can be produced from a variety of sources

Poplar chips

SwitchgrassSugarcane

Corn

Ethanol from Corn

Only a small portion of the starch present in the corn is useful for producing Ethanol

(Overview)

Ethanol from Corn

(Overview)

Ethanol from Corn

Feed grain processing

• Increase surface area for reactions

• Remove cellulosic material – pure starch

• Slurry: piped through processing plant

Corn Starch

Starch vs. Sugar

• Starch is a polysaccharide carbohydrate consisting of a large number of glucose monosaccharide units joined together by glycosidic bonds.

– All plant seeds and tubers contain starch which is predominantly present as amylose and amylopectin.

Alton Brown’s TV show Good Eats (Food Network) does a great job at

teaching about chemistry

5106 OHC

Macromolecule

amorphous, insoluble in water, no sweet taste

Monosaccharides: simple sugars(e.g. glucose)

Ethanol from Corn

Cooking/Fermentation

• Starches converted to simple sugars: fructose, glucose, sucrose, etc.

• Saccharification (enzymes)

Starch Sugar

Glucose, Sucrose, Fructose, etc.

• Saccarification (Hydrolysis)

• Hydrolysis is a chemical reaction or process in which a chemical compound is broken down by reaction with water.

• Cellulase refers to a class of enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze the cellulolysis (or hydrolysis) of cellulose

Glucose: monosaccaride with 6 carbons in a cyclical structure

(power-houses for many biological systems)

6126 OHC 112212 OHC

Ethanol from Corn

Cooking/Fermenting

• Sugars digested – Ethanol waste product

• Fermentation (yeast)

Sugar Ethanol

Fermentation

• Yeast (a variety of sources possible)

– Enzymatic– Anaerobic process– Temperature and PH dependent

(metabolic waste products)

Yeast is a Fungus (budding)

glycolysis

Pyruvate

Glucose

Acetyldehyde

Ethanol

Ethanol from Corn

Extraction/Distillation

• “Beer” = 8-12% ethanol

• Separate Ethanol

• Increase purification

Ethanol+ Ethanol

Ethanol from Corn

Extraction/Distillation

• “Beer” = 8-12% ethanol

• Separate Ethanol

• Increase purification

Clean-Up + Reuse ByProducts

E85/E10

• Ethanol increases the octane of fuel• E10 – 10% ethanol blend (gasohol)

– Cars can run on up to 10% ethanol without needing modifications

• E85 – 85% ethanol– Only certain cars can run with this blend

• Changing a car to E85 is not as simple as it seems (MotorTrend segment)

The logo from e85tips.com

Activity: Ethanol Production

• BioEthanol generator demonstration

Combustion of Ethanol

Combustion of Ethanol

Air is not pure oxygen

Waste products can also include nitrous oxides (NOxs)

Simple fuel – Simple reaction

1. Hydrocarbons: this class is made up of unburned or partially burned fuel (smog +toxic).

2. Nitrogen oxides (NOx): generated when nitrogen in the air reacts with oxygen under the high temperature and pressure conditions inside the engine. (smog + acid rain)

3. Carbon monoxide (CO): product of incomplete combustion

4. Carbon dioxide (CO2): an increasing concern as its role in global warming as a greenhouse gas

5. Particulates: micron sized particles

6. Sulphur oxide (SOx) general term for oxides of sulphur, mostly sulfur dioxide and some sulfur trioxide

Combustion of Gasoline

Calorimetry ExperimentsBomb/Combustion Calorimeter needed

Can determine the molar heat of combustion for any number of fuels

Activity: Energy Density of Ethanol

Energy Density of Ethanol

Biodiesel is standard in Europe

100% Ethanol = 24 MJ/LMJ = mega-Joule = 1 x106 J of energy

BioGas

• Landfill Gas– Network of buried pipes – capped landfill– Captures methane and directs it to purification

BioGas

• Agricultural Resources

• Large-scale farms– Manure digesters (living systems)

BioGas Production Experiments

• Methane production– Fermentation of … most anything– Timeline: Weeks-to-Months– Bacteria – anaerobic

• Manure is a good source …. Mmmm• Safety concerns

Carbon-dioxide first

Methane later

Where is Ethanol produced• U.S. – Ethanol from Corn

– Iowa, Illinois, Minnesota, Nebraska

• Brazil – Ethanol from Sugarcane• Vehicles there have been running on 100% ethanol

for decades

Existing and planned U.S. corn processing plants (8/30/06).

Iowa corn processing and ethanol plants, current and planned (10/26/06).

(3.8 billion liters) of ethanol a year

Local Production, Local Consumption?

Harvest – Ship to Processing – Processing – Ship to

Corrosion Issues• Alcohols are more conductive

than gasohol - acts as an electrolyte and promotes galvanic corrosion

• Materials affected: brass, zinc, lead, and aluminum.

• Corrosion products can damage or block fuel system components

• Plastics and rubber components degrade in the presence of ethanol as well

Gasohol (1970's) bad press - complaints about engine problems, corroded fuel lines, etc.

PipelineA number of clues have arisen indicating a problem (area for research and development) with increased ethanol use …..

Pipeline = Most Efficient Transport/Delivery System

Video mentions close proximity of ethanol plant to natural gas pipeline …. But focuses on rail and truck in its content

+ +

PipelineA number of clues have arisen indicating a problem (area for research and development) with increased ethanol use …..

•Water affinity problem • Ethanol is water soluble • Water accumulation in pipelines is normal

•Ethanol-related corrosion problems • Result from how ethanol behaves in the pipe• Lead to various forms of corrosion

• internal stress • corrosion cracking

• Damage is accelerated at weld joints

We are still finding some of these things out --- and developing “fixes” as we go ...

Hallmark of BioFuels: Debate

Is it worth it? Are there other complicating issues? Are there other options?

Competition with Food Resources

• Being a ‘farmed’ fuel, biofuels compete with food supply

• Increased demand for arable land

• Conversion of crops to corn

• Increased cost of corn propagates through markets

One of the many issues associated with BioFuels that is currently ‘hot’

CO2 Payoff Questions

Hidden Costs

Fossil Fuel Requirements for Farming, Transportation of Materials ,etc.

Cellulosic Ethanol Production

Goal: Cellulosic Ethanol 10x