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


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)



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



Schematic of Petroleum Refining



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…



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



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




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



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



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



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



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



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)



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



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



Biofuels Production: Process Flowsheet

Base Catalyzed Esterification of Oils

Source: Lurgi Process




Biodiesel Fractionation Processes



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

Overview



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




2. Adsorption/Chromatographic, Liquid-Liquid extraction techniques Require multiple solvents, expensive processing components, energy intensive

High cost, low selectivity, unsuitable for large scale processing




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



Urea-biodiesel clathration


Foundational Technology: Urea Clathration

Scalable/robust, based on alkene structure, energy efficient www.renaltenergy.com


Biodiesel Standard Process



Biodiesel Fractionation Process



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



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





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



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



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




Cold Flow Properties:



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]



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



Biodiesel Production: Challenges

• Glycerol Utilization - Better utilization of glycerin • Improve Esterification - Processing steps • Fuel to diesel engine specifications - Minimize impurities



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


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



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



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



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




Applications Summer/winter diesel fuel blend stocks

Aviation jet fuel

Solvents

Chemical feedstocks (enhanced reactivity)

Future research on catalytic cracking/reforming/alkylation/cyclization



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



Summary

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


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