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Bioenergy Fundamentals Biomass – solar energy stored in plant/animal tissue Chemical Composition 25% Lignin 75% Carbohydrates and Sugars PowerPoint PPT Presentation


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Bioenergy Fundamentals Biomass – solar energy stored in plant/animal tissue Chemical Composition 25% Lignin 75% Carbohydrates and Sugars Carbohydrate – many sugars bound together into long polymer chains Carbohydrates consist of cellulose/ hemicellulose

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Bioenergy Fundamentals Biomass – solar energy stored in plant/animal tissue Chemical Composition 25% Lignin 75% Carbohydrates and Sugars

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Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Bioenergy Fundamentals

Biomass – solar energy stored in plant/animal tissue

Chemical Composition

25% Lignin

75% Carbohydrates and Sugars

Carbohydrate – many sugars bound together into long polymer chains

Carbohydrates consist of cellulose/hemicellulose

Lignin – a non-sugar polymer, like plant mortar

- Glue that holds cellulose fibers together


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Lignin Molecular Structure


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Carbohydrate/Cellulose Structure


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Origins of Biomass

CO2 + H2O + Sunlight = Biomass + O2

Solar Radiation  Chemical Energy

Cyclic Process

14% of worldwide energy consumption

40-90% in developing world

4% of U.S. electricity from biomass (9000 MW)

Mass of total living matter = 2000 billion tons

or 300 tons per person

Net Annual Production = 400,000 million tons


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Energy Content of Biomass

Moisture content causes huge variation

8-20% for wheat straw

30-60% for wood

75-90% for animal manure

Dry biomass - 17-20 GJ/ton (coal 20-30 GJ/ton)

Biomass – less ash, toxic metals, sulfur, etc.

Wide range of uses

Cyclic process that is potentially sustainable


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Common Pathways

Developed, Widespread Use

First Generation Biofuels – Ethanol, Biodiesel

Landfill and Digester Gases

Industrial and Agricultural Wastes (Sawmills…)

Future Development

Second Generation Biofuels – Range of feedstocks, conversion processes

Advanced use of residential, industrial and agricultural wastes, byproducts and crops


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Ethanol


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Ethanol

Substitute for Gasoline

Produced by fermenting sugar cane or sugar beet

Produced in large quantities in Brazil

Can also be made from vegetable starches – requires milling and treatment with acids

Energy content = 30 GJ/ton

Energy content about 2/3 that of gasoline

C2H5OH


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Ethanol

So, you pull up to the gas station in your flexible fuel vehicle and see that gasoline is selling for $3.00 per gallon and ethanol (100%) is selling for $2.12 per gallon. Which is a better deal?


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Ethanol

Commonly blended with gasoline

Up to 10% ethanol with gas, octane boost

85% ethanol + 15% gasoline = E85

Octane rating – what is it…

Octane rating of ethanol about 113

5-10% blends boost octane rating 2-4 points

Before ethanol was used, MTBE


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Ethanol

Methyl tert-butyl ether, C5H12O

Pollutes groundwater

- leaks from storage

- leaks from fueling

- leaks from industry

Also used as oxygenate

- Winter fuel blends

- Reduces CO emissions


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Ethanol


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

  • Ethanol

  • Corn stored at plant (7-10 day supply)

  • Screened to remove debris, milled into flour

  • Cooking (aka. Mashing)

    • Hot slurry (mixed with water, enzyme added, heated for 30-45 minutes)

    • Liquefaction –time, heat and enzymes break down starch into shorter chains

  • Saccharification – Glucoamylase enzyme breaks short chains into simple sugars

  • Fermentation – Yeast converts sugar into ethanol, 50-60 hours to 15% alcohol “beer”


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Ethanol

Distillation – Difference in boiling point of alcohol and water, produces 95% alcohol

Dehydration – Remaining water from 190 proof alcohol removed through molecular sieve (uses different sizes of molecules)

Byproducts

- CO2 from fermentation

- Spent grains – turned into cattle feed


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Biodiesel

Diesel fuel from vegetable oil (or animal fat)

Veg oils – fatty acids (triglycerides)

Long chain alkyl (methyl, propyl, ethyl) esters

An ester group…


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

1 triglyceride + 3 alcohol

3 ester alcohol + 1 glycerine

catalyst

Me

Me

Me

O

O

O

O =

O =

O =

HO

O

O

O

O =

O =

O =

3 MeOH

HO

KOHCatalyst

HO

Biodiesel(Methyl Ester Alcohol)

Triglyceride

Glycerol

Transesterification Reaction

PROF. NAVEEN KUMAR, DELHI COLLEGE OF ENGINEERING, DELHI, INDIA


Molecular structure

Molecular Structure

Fats and oils have quite big molecules with a spinal of glycerol on which are bond three fatty acid rests.

By the transesterification, the fatty acid rests are removed from the glycerol and each is bond with methanol.

The products are one mole glycerol and three mole of fatty acid methyl ester.


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Biodiesel


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Biodiesel

For every ton of biodiesel, 100 kg of glycerol

Market for glycerol used to exist… not anymore

(everybody is making biodiesel)

Companies are trying to find ways to use it

(Cargil, Dow, etc.)

High water content, not cheap to separate

Market for free/cheap veg oil used to exist…

(but everybody is making biodisel)


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Biodiesel


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

What the ?!!?!?!


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Biodiesel

Sources

- Palm (41 million tons per year)

- Soybean (38 million tons per year)

- Rapeseed (aka Canola, 18 mil. tons per year)

- Sunflower, peanut, cottonseed, olive, etc.

Can be run 100% or any blend

Volumetric heating value 10% less than diesel

Water emulsifications a serious problem


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Pyrolysis

Decomposition of solids

- High temperatures

- Absence of oxygen

Pyrolysis of biomass

- Heated to 400-500oC for a few seconds

- Yields a bio-oil

- Not a fuel that can be burned directly

Currently in commercialization phase


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Catalytic Reforming

Biogas transformed into liquid fuel

Typically a CO and H2 blend to produce gasoline or diesel substitute

Key component is the catalyst

Transition metals (iron, cobalt, ruthenium)

Most common method is called Fischer-Tropsch

Short course in catalysis…


Bioenergy fundamentals biomass solar energy stored in plant animal tissue chemical composition 25 lignin 75 carbohydrates and sugars

Technical Skills for Liquid Biofuels

Combustion

- Stoichiometry (proper A/F ratio, etc)

- Heating value of a fuel or mixture (by vol)

- Product gas composition

- Assessing pollutant, GHG emissions

Otto, Diesel Cycle Fundamentals

Life Cycle Analysis

- Quantification of energy, GHG, emissions

- Does it make sense to do this?

- Where should we focus to improve process?


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