Biodiesel Fuels, Issues Trends Challenges

RENALT ENERGY
Renewable and Alternative Energy for the New Millennium
Biodiesel Fuel
Issues, Trends and Challenges
By Gerard B. Hawkins
Executive Director
RENALT ENERGY
www.renaltenergy.com

RENALT ENERGY
Petroleum Background
Geologically mined non-renewable resource
Complex mixture of mainly hydrocarbon
structures (alkane / alkene, aromatics, wide
range of molecular weights, C4-C100+)
Multiple sources differing in composition
(geographical, contaminants)

RENALT ENERGY
Needs of Petroleum Industry
Unusable in original state (viscous, black gunk), low cost
Must be able to handle differing feedstocks and produce
consistent products
Needed processing technology to make useful
differentiated products, e.g. gasoline, diesel, kerosene,
chemical feedstocks, etc.
Current issues are economic and political

RENALT ENERGY
Schematic of Petroleum Refining

RENALT ENERGY
Foundational Technology: Distillation

Diesel Engines Pollute the Air
 Diesel exhaust is toxic and carcinogenic
 20,000 Americans die each year from lung disease
from diesel exhaust particulates
 400,000 Americans suffer from asthma and lung
disease related to diesel exhaust; problem acute in
West Oakland, BayView
 Diesel exhaust is even more of a problem in
congested cities with older diesels
 Sulfur oxides in exhaust lead to acid rain
 Environmental Justice projects in SF…
RENALT ENERGY

Diesel Engines Here for Long Term
 Diesel engines are still one of the most reliable,
energy efficient & powerful propulsion systems; long
engine life
 New diesel engine technologies & regulations will
reduce exhaust emissions dramatically; plus new
after-treatment
 Diesel-Electric hybrids do help reduce impact;
electric buses have decades of success on the steep
hills of SF
 CNG buses in widespread use but problems persist
 However, the diesel fuel remains toxic to workers &
the public as volatile flammable liquid; threat to
groundwater
RENALT ENERGY

Diesel Engines Here for Long Term
 2/3 of our petroleum is imported now; jobs/trade
balance
 Diesel fuel production at refineries in the western
states cannot keep up with the demand – opportunity
for biofuel
 The long-term sustainability of non-renewable
petroleum fuel is a real issue for the US and
developing countries
 The rising price of diesel fuel is promoting alternative
fuel
RENALT ENERGY

RENALT ENERGY
Needs of Biodiesel Industry
Useful existing feedstock (oil), high cost
Quality control; Must be able to handle differing
feedstocks and produce consistent products
Needed processing technology to make differentiated
products, e.g. cold flow products
Major current issue is product performance with
respect to cold weather

RENALT ENERGY
Biodiesel Background
Biologically produced renewable resource
Hydrocarbon-like ester structures (mainly alkane/alkene
structures, relatively narrow molecular weight distribution
(C12-C20)
Multiple sources differing in composition
(plant/animal/microbial, few contaminants)

Enter Biodiesel
 A diesel displacement fuel made from plant oils,
animal tallow or recycled cooking oils through a
chemical process to remove glycerin and yield
methyl or ethyl esters optimized for combustion
 Renewable, agriculturally produced alternative fuel
to displace imported petroleum; similar price
 Biodiesel itself is non-toxic, non-flammable and non-
volatile, making it safer to handle & store
 Biodiesel contains little sulfur and no aromatics
 When blended with petroleum diesel or burned as a
pure fuel, biodiesel can significantly reduce diesel
engine exhaust PM, CO, HC, S & toxics
RENALT ENERGY

Growing Biodiesel Feedstock:
Canola and Mustard oil seed crops
 Rotation crops for wheat farmers in CA, Eastern
Washington, Oregon, Idaho, NV
 High oil yield strains yield 100-150 gallons of
biodiesel per acre (double yield of soy)
 Dry farmed and drought tolerant crops
 Plant debris contributes nitrogen to soil
 Glucosinolate in plant and meal is an organic
fungicide, pesticide & herbicide -reduces costs for
farmer; added benefits
RENALT ENERGY

Biodiesel Raw Materials
Oil or Fat Alcohol
Soybean, Canola Methanol
Corn, Safflower Ethanol (rare)
Mustard, Cottonseed
Sunflower Catalyst
Palm, Coconut Sodium or potassium
Jatropha, Castor bean Hydroxide
Beef tallow, pork lard, poultry fat
Used cooking oils & grease, FOG
RENALT ENERGY

Biofuels: Production Methods
Biodiesel Production Methods
•Base catalyzed transesterification of oil
•Direct acid catalyzed transesterification of oil
•Convert oils into fatty acids and then to biodiesel
RENALT ENERGY

Biofuels Production: Reaction Mechanism
Base catalyzed Esterification reaction
CH2OCOR''„ CH2OH R'''COOR
CHOCOR'' + 3 ROH Catalyst CHOH + R''COOR
CH2OCOR„ CH2OH R'COOR
(100 lbs) (10 lbs) (10 lbs) (100 lbs)
Oil or Fat Alcohol (excess) Glycerin Biodiesel
(Triglyceride)
RENALT ENERGY

The Biodiesel Reaction
Vegetable Oil or
Animal Fat
(100 lbs.)
+
Methanol or
Ethanol
(10 lbs.)
Biodiesel
(100 lbs.)
+
Glycerine
(10 lbs.)
+ catalyst (hydroxide)
Combining Yields

Transesterification Reaction
H O
 
H - C - O - C - CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH3

 O
 
H - C - O - C - (CH2)7 -CH = CH(CH2)7 CH3 + 3 H3 - C -OH --------------->
 + -OH
 O Methanol Catalyst
 
H - C - O - C - (CH2)7 -CH = CHCH2 CH = CH(CH2)4 CH3

H Triglyceride
Vegetable / Soybean Oil
RENALT ENERGY

Biodiesel = Methyl esters of
Tryglyceride fatty acid chains
H O
 
H - C - OH CH3 - O - C - (CH2)16 CH3

 Methyl Stearate (saturated ester)
 O
 
H - C - OH + CH3 - O - C - (CH2)7 -CH = CH(CH2)7 CH3

 Methyl Oleate (mono-unsaturated ester)
 O
 
H - C - OH CH3 - O - C - (CH2)7 -CH = CHCH2 CH = CH(CH2)4 CH3

H Methyl Linoleate (di-unsaturated ester)
Glycerin
Biodiesel Methyl Esters

Catalyst-
Mixing
Methanol
Catalyst
Transesterification
Vegetable Oils, Used
Cooking Oil,
Animal Fats
Neutralization Phase Separation Re-neutralization
Methanol-
Recovery
Purification
Methanol-
Recovery
Quality
Control
Glycerin
Purification
Neutralizing Acid
Crude Biodiesel
Methyl
Ester
Crude
Glycerin
Pharmaceutical
Glycerin
Recycled
Methanol
If desired
Biodiesel Production Process
RENALT ENERGY

Biofuels Production: Process Flowsheet
Base Catalyzed Esterification of Oils
Source: Lurgi Process
RENALT ENERGY

RENALT ENERGY
Biodiesel Fractionation Processes

RENALT ENERGY
Historical comparison between development of
petroleum/biodiesel fuel processing
– Technologies to create multiple fuel products
Description of new biodiesel fractionation process
Opportunities/Applications
Overview

RENALT ENERGY
Conventional Biodiesel Fractionation Technologies
1. Thermal fractionation (with or without solvent):
Crystallization/filtration process, very low yields, long
process time, high losses due to co-crystallization /
inclusion
Solvent crystallization gives higher yields, but requires
significant refrigeration/very low temperatures

RENALT ENERGY
Conventional Biodiesel Fractionation
Technologies
2. Adsorption/Chromatographic, Liquid-Liquid
extraction techniques
Require multiple solvents, expensive processing
components, energy intensive
High cost, low selectivity, unsuitable for large scale
processing

RENALT ENERGY
Conventional Biodiesel Fractionation
Technologies
3. Lipase catalysis
Relies on the selectivity of certain lipases to hydrolyze
only the unsaturates
High selectivity but very low yields, process time runs
into days
Extremely expensive

RENALT ENERGY
Urea-biodiesel clathration

RENALT ENERGY
Foundational Technology: Urea Clathration
Scalable/robust, based on alkene structure, energy efficient

RENALT ENERGY
Biodiesel Standard Process

RENALT ENERGY
Biodiesel Fractionation Process

RENALT ENERGY
Urea is only additional component, which is
100% recycled
Only additional major equipment is mixing
tank/centrifuge (some additional tankage)
Only added energy input is for added
methanol evaporation (if any)
Differential Processing

RENALT ENERGY
Can be integrated into existing/new
biodiesel processing plants
Scalable, robust, simple process
Estimated differential costs 5-10 cents/gal

RENALT ENERGY
Usable with any biodiesel feedstock or blend,
e.g. soybean oil, canola, palm oil, coconut oil,
lard, waste restaurant fat, etc.
Controllable product properties based on
Alkane / alkene composition, carbon chain
Length
Yields will depend on feedstock Composition
Serial/staged fractionation is possible to obtain
multiple products

Biodiesel: Fuel Quality for Diesel Engines
•ASTM Specification for B100 for Blending has been developed
(D6751)
• Changes being considered to improve quality
•Attempts are being made to address stability and compatibility
with newer diesel technology concerns of engine manufacturers
• Additional research required to define and test for stability
• Lack of data relating stability and deposit formation in engine
RENALT ENERGY

Biodiesel B100 Properties
 Ultra low Sulfur (typically < 8 ppm)
 No Aromatics (& low PAH emission)
 High Cetane (> 52, improved ignition)
 High Lubricity (even 1% restores ULSD lubricity)
 Biodegradable (soil, marine, aquatic ecosystems)
 Non-Toxic (but harmful to aquatic habitats)
 Non-volatile (< 2 mm Hg vapor pressure)
 Non-flammable (Flash Point > 300 Deg F)
 Solvent action of fuel on seals, gaskets, tank liners
 Must meet ASTM 6751 specifications or problems
result with precipitations, contaminants & failures
RENALT ENERGY

Biodiesel Properties
Properties ASTM Standard-D6751
• Reaction completion
• Glycerin removal
• Catalyst removal
• Free fatty acids removal
Ester Viscosity
mm²/s
Cetane No. ΔHg
kJ/kg Tflash
°C
CP
°C
PP
°C
Methyl 4.08 46.2 39,800 191 2 -1
Ethyl 4.41 48.2 40,000 174 1 -4
Isopropyl 52.6 – – -9 -12
N-Butyl 5.24 51.7 40,700 185 -3 -7
No. 2 Diesel 2.39 45.8 45,200 78 -19 -23
RENALT ENERGY

RENALT ENERGY
Cold Flow Properties:

RENALT ENERGY
Biodiesel quality depends on feedstock

Important Biodiesel Parameters
 Complete Reaction to >97% conversion to avoid
partially reacted glycerides remaining in fuel
 Removal of Glycerin (gums engine valves)
 Removal of Catalyst (caustic hydroxide)
 Removal of Alcohol (flash point issues)
 Absence of Free Fatty Acids or Soaps
 Should be insured via ASTM D 6751
[New revisions coming including oxidation stability]
RENALT ENERGY

Production Process Highlights
 Most transesterification reactions achieve 97-99%
conversion of oils & fats to esters
 Co-product glcyerin & unreacted reagents are
largely removed by gravity or centrifugation; traces
can remain in fuel
 Methanol is flashed off and recovered
 Water washes remove last traces of catalyst,
methanol, glycerin and soaps
 Final polishing steps essential to remove traces of
oils, mono-, di-, tri-glycerides & glycerin to achieve
ASTM spec B100
RENALT ENERGY

Biodiesel Production: Challenges
• Glycerol Utilization
- Better utilization of glycerin
• Improve Esterification
- Processing steps
• Fuel to diesel engine specifications
- Minimize impurities
RENALT ENERGY

RENALT ENERGY
Biodiesel: Production vs Capacity

Biodiesel Specification ASTM 6751
Property ASTM Method Limits Units
Flash Point 93 130 min. degree C
Water & Sediment 2709 0.05 max. vol.%
Carbon Residue 4530 0.05 max. wt. %
(100% sample)
Sulfated Ash 874 0.02 max. wt. %
Kin. Viscosity, 40C 445 1.9 - 6.0 mm²/sec.
Sulfur 5453 0.05 max. wt. %
Cetane 613 47 min.
Cloud Point 2500 By Customer degree C
Copper Corrosion 130 No. 3 max.
Acid Number 664 0.80 max. mg KOH/g
Free Glycerin 6854 0.020 wt. %
Total Glycerin 6854 0.240 wt. %
Phosphorous 4951 10 max ppm
Distillation, T90 AET 1160 360 max degree C
RENALT ENERGY

ASTM D6751 Highlights
 Acid number – for degrading, oxidized fuel
 Flashpoint – for residual methanol
 Water & sediment – fuel fouling, deposits
 Sulfated ash – for residual catalyst
 Total glycerin – for incomplete conversion, detects
residual mono, di and tri glycerides
 Free glycerin – inadequate fuel washing
 New ASTM updates will include specs for
Na+, K+ and oxidation stability
RENALT ENERGY

Biodiesel: Economics
Assumptions
• Plant size: 60 million gallons
• Feedstock cost: 80%
• 7.5 lbs feedstock/gallon biodiesel
• Operating cost (excluding feedstock): $0.42/gallon
• Credit for glycerin and other by-products:
$0.05/gallon
RENALT ENERGY

Biodiesel: Economics
Net operating profit= Revenues –Operating cost
(excluding capital and other fixed costs )
RENALT ENERGY

How can Biodiesel be used?
 In low levels with petrodiesel ULSD (B2 - B5) to
restore the lubricity after hydrotreatment that
removes the sulfur and lubricating compounds
 As a blending stock with regular diesel (B20)
 As a pure fuel (“Neat” or B100 in niche markets)
primarily in CA and among biodiesel enthusiasts
In all diesel engines, with no conversion for blends of
20% or less; Check fuel tanks
RENALT ENERGY

RENALT ENERGY
Applications
Summer/winter diesel fuel blend stocks
Aviation jet fuel
Solvents
Chemical feedstocks (enhanced reactivity)
Future research on catalytic
cracking/reforming/alkylation/cyclization

RENALT ENERGY
Summary
Description of a novel simple fractionation process for
biodiesel fuels
Low energy, environmentally benign, low cost, robust
/scalable, compatible with existing/new biodiesel
synthesis plants

RENALT ENERGY
Summary
Usable with variety of feedstocks (plant, animal,
microbial lipids)
Controllable cold temperature properties suitable for
ground, aviation fuels; also potential chemical
feedstocks

Biodiesel Fuels, Issues Trends Challenges

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

Similaire à Biodiesel Fuels, Issues Trends Challenges

Similaire à Biodiesel Fuels, Issues Trends Challenges (20)

Plus de Gerard B. Hawkins

Plus de Gerard B. Hawkins (20)

Dernier

Dernier (20)

Biodiesel Fuels, Issues Trends Challenges