RE technology options:

Prof. R. Shanthini 09 Feb 2013

RE technology options:

- Hydroelectric Hydroelectric

- Solar Solar

- Wind Wind

- Geothermal

- Marine (Wave and Tidal)

- BiofuelsBiofuels (Biomass Biomass , BioethanolBioethanol and Biodiesel Biodiesel )


Biodiesel

Biodiesel can be used in compression ignition engines with little or no modifications.

Biodiesel is derived from renewable lipid sources, such as vegetable oil or animal fat.

Biodiesel is a mixture of mono-alkyl esters of long chain fatty acids.


Biodiesel production (traditional method)

Biodiesel is made by chemically combining

any natural oil or animal fat (major component of which is triglyceride)

with an alcohol (methanol / ethanol / iso-propanol)

in the presence of a cataylst (NaOH or KOH)

triglycerids methanolmethyl Ester

(biodiesel)

glycerol(glycerin)+ +KOH

This process is known as transestrification.


Biodiesel production (traditional method)

Triglyceride

Methanol

Biodiesel: mixture of

methyl esters

Glycerol

KOH

Transestrification is a reaction of an ester with an alcohol to form a different ester.


Triglyceride Glycerol


Triglyceride to Free fatty acids


Free fatty acid (FFA) to biodiesel

Free Fatty Acid Methyl ester Water

H2SO4

This process is known as estrification (which is a reaction of an acid with an alcohol to form an ester).

Methanol

Free Fatty Acid Soap Water

NaOH

This process is known as saponification, in which soap is produced.

Base

Na


Biodiesel feedstock

Vegetable oils: - Rape seed/Canola (> 80%) - Soybean (USA, Brazil) - Cotton seed (Greece) - Palm (Malaysia) - Peanut - Sunflower (Italy, FranceSouth) - Linseed & Olive (Spain) - Safflower - Coconut - Jatropha (Nicaragua) - Guang-Pi (China)

Animal fats: - Beef tallow (Ireland) - Lard - Poultry fats

Waste oils: - Used frying oils (Austria)

Other feed stocks: - Algae


Biodiesel production process

(5 to 25% FFA)


Biodiesel blends used in diesel engines

B2 – 2% biodiesel and 98% petro diesel



http://www.mechanicalengineeringblog.com/tag/biodiesel-chemistry


Biodiesel from algae

Claimed output of 10,000 gallons of biodiesel per hectare per year.


Biodiesel from algae

10,000 gallons of biodiesel per hectare per year

= 37854 litres per 2.47 acres per year

= 15325 litres per acre per year

= 15325 / 160 litres per perch per year

= 96 litres per perch per year

= 96 /12 litres per perch per month

= about 8 litres per perch per month

Claimed output of 10,000 gallons of biodiesel per hectare per year.


Algae biodiesel life cycle

K Sander & GS Murthy from Int J Life Cycle Assess (2010) 15:704–714

Algae harvesting from habitat

Culture maintenance/storage

Growth in open pond

Harvesting

Separation of cell components

Carbohydrate and protein contents

Conversion to biodiesel

Transportation and distribution

customer

Combustion in vehicles




Manufacture / construction of

open pond

Manufacture / maintenance of

equipment

Acquiring resources of manufacture

Partial treatment of wastewater

Crude oil drilling

Crude oil refining

Hexane purification



Growth in open pond

Harvesting






Sodium methoxide

Catalyst production

Salt mining HCl production

Conversion to biodiesel

Methanol production

Natural gas and methane

refining

Natural gas and methane

extraction

Metal mining

Salt mining NaOH production



Manufacture / maintenance of

equipment

Transportation and distribution

customer

Combustion in vehicles

Acquiring resources of manufacture

Crude oil drilling

Crude oil refining





Hexane purification



Growth in open pond

Harvesting



When harvested, there is 0.05% algae in wastewater.

It has to be brought to 91% algae in wastewater (required by the hexane extraction step).

This is achieved by a dewatering process (filtration or centrifugation) followed by drying in a natural gas fired dryer.

Algae dewatering is the most significant energy sink in the entire process.




Algal lipid content

(%, w/w)

Total energy input

(MJ / 1000 MJ algae biodiesel)

40 2,500

30 3,292

20 4,878

15 6,470

10 9,665

5 19,347




In most algae species, there is typically a larger percentage of carbohydrates than lipids in an algae cell.

With lipid removed to produce biodiesel, the remaining carbohydrates makes an excellent feedstock for bioethanol.

Every 24 kg of algal biodiesel produced (one functional unit,1,000 MJ algae biodiesel), 28.1 kg carbohydrates and cellulose coproduct are also produced.

With less than 2% lignin, bioethanol processing becomes more favourable.


LCA is a tool to assess the potential environmental impacts of product systems or services at all stages in their life cycle – from extraction of resources, through the production and use of the product to reuse, recycling or final disposal.

Life-cycle assessment (LCA)


Limitations of LCA: some examples

• Drawing the boundaries

– Cradle to Gate or Cradle to Grave?

Life Cycle Assessment (LCA) 21


Life-cycle assessment (LCA)

supply transport

manufacturing

packagingUse

disposal

Cradle to Gate(4 stages)

Cradle to Grave(6 stages)


Limitations of LCA: some examples

• Weights given to different impacts

– What is more important? Use of water resources or CO2 emissions?

• Drawing the boundaries

– Cradle to Gate or Cradle to Grave?

– Do we consider supporting activities for the system?

• Example: a warehouse stores the product. Direct energy consumption for the warehouse should be part of the system, but emissions associated with garbage pickup for the facility ????

Life Cycle Assessment (LCA) 23


The 1.7 kg microchip: Environmental implications of the IT revolution

Source: http://www.enviroliteracy.org/subcategory.php/334.html

by Eric D. Williams, Robert U. Ayres, and Miriam Heller, The 1.7 Kilogram Microchip: Energy and Material Use in the Production of Semiconductor Devices. Environmental Science & Technology (a peer-reviewed journal of the American Chemical Society), 2002, 36 (24), pp 5504–5510

One 32 MB DRAM chip (weight = 2 gram)

1600 g of fossil fuels

71 g of chemicals

32,000 g of water

700 g of elemental gases (mainly nitrogen)

An example life-cycle assessment:


Life cycle assessment of biodiesel production from free fatty acid-rich wastes

J. Dufour and D. Iribarren in Renewable Energy 38 (2012) 155-162

Biodiesel production systems considered:

- Acid-catalyzed esterification followed by alkali-catalyzed transesterification of waste vegetable oils (used cooking oil)

- Esterification and transesterification of beef tallow

- Esterification and transesterification of poultry fat

- Acid-catalyzed in-situ transesterification of sewage sludges



Impact potentials evaluated:

- Global warming (GWP) in kg CO2 eq.

- Acidification (AP) in kg SO2 eq.

- Eutrophication (EP) in kg PO43- eq.

- Ozone layer depletion (ODP) in mg CFC-11 eq.

- Photochemical oxidant formation (POFP) in kg C2H4 eq.

- Cumulative non-renewable energy demand (CED) in GJ eq.

Life cycle assessment of biodiesel production from free fatty acid-rich wastes


Biodiesel production system


FFA-rich waste

Transportation

Transportation

rendering

Esterification

Trans-esterification

Transportation

Electricity production

Thermal energy

production

Water suppy

Chemicals production

Wastes

Waste management

Biodiesel Glycerol

Other inputs

Other outputs



FFA-rich waste

Trans-esterification

Transportation

Electricity production

Thermal energy

production

Water suppy

Chemicals production

Wastes

Waste management

Biodiesel Glycerol

Other inputs

Other outputs

Biodiesel production system (for sewage sludges)


Inventory of input data for the production of 1 t Biodiesel


waste rendered rendered dried Materials vegetable beef poultry sewage

oils tallow fat sludgeLipid feedstock 1205 1015 1013 10,000 kg

Methanol 112.67 113.32 99.00 670.18 kg

Sulphuric acid 0.15 - -76.35 kg

Calcium oxide 0.10 - - - kg

Water 56.08 71.32 32.00 0.88 kg

Sodium hydroxide 9.80 4.00 5.00 - kg

Sodium methoxide - 11.00 12.00 - kg

Phosphoric acid 7.95 - - - kg

Hydrogen chloride - 6.00 7.00 - kg

Hexane - - - 76.28 kg




waste rendered rendered dried Energy vegetable beef poultry sewage

oils tallow fat sludgeThermal (rendering) 1628.93 - - - MJ

Electrical (rendering) 133.12 - - - kWh

Thermal (esterification) 222.30 175.94 90.04 - MJ

Electrical(esterification) 31.43 28.93 10.08 - kWh

Thermal (transesterification) 1650.84 1733.48 1886.96 2542.95 MJ

Electrical(transesterification) 20.34 30.36 28.98 28.47 kWh




waste rendered rendered dried Transport vegetable beef poultry sewage(by lorry) oils tallow fat sludge

To rendering plant 187.76 - - - t km

To biodiesel plant 291.31 293.44 292.76 - t km


Inventory of output data for the production of 1 t Biodiesel


waste rendered rendered dried Materials vegetable beef poultry sewage

oils tallow fat sludge

Biodiesel 1.00 1.00 1.00 1.00 t

Glycerol 102.21 115.64 109.00 129.05 kg

Salts to landfill 16 9 10 - kg

Hazardous liquid waste 30.46 24.00 26.00 - kg

Organic waste to landfill 85.40 - - - kg

Sludge - - - 2 t



Global Warming Potential (kg CO2 eq per GJ of energy supply)

0

20

40

60

80

100

Was

te v

eget

able

oils

Beef t

allo

w

Poultry

fats

Sewag

e sl

udges

Soybea

n

Rapes

eed

Low-sulp

hur die

sel

Environmental profile of different transportation diesel fuels



Acidification Potential(kg SO2 eq per GJ of energy supply)

0

0.1

0.2

0.3

0.4

0.5

0.6

Was

te v

eget

able

oils

Beef t

allo

w

Poultry

fats

Sewag

e sl

udges

Soybea

n

Rapes

eed

Low-sulp

hur die

sel




Eutrophication Potential(kg PO4 ions eq per GJ of energy supply)

00.05

0.10.15

0.20.25

0.30.35

0.4

Was

te v

eget

able

oils

Beef t

allo

w

Poultry

fats

Sewag

e sl

udges

Soybea

n

Rapes

eed

Low-sulp

hur die

sel




Ozone layer Depletion Potential(mg CFC-11 eq per GJ of energy supply)

0

2

4

6

8

10

12

Was

te v

eget

able

oils

Beef t

allo

w

Poultry

fats

Sewag

e sl

udges

Soybea

n

Rapes

eed

Low-sulp

hur die

sel




Photochemical Oxidant Formation Potential(kg C2H4 eq per GJ of energy supply)

0

0.01

0.02

0.03

0.04

0.05

0.06

Was

te v

eget

able

oils

Beef t

allo

w

Poultry

fats

Sewag

e sl

udges

Soybea

n

Rapes

eed

Low-sulp

hur die

sel





Cumulative Non-renewable Energy Demand(GJ eq per GJ of energy supply)

00.20.40.60.8

11.21.4

Was

te v

eget

able

oils

Beef t

allo

w

Poultry

fats

Sewag

e sl

udges

Soybea

n

Rapes

eed

Low-sulp

hur die

sel

Documents

RE technology options: