biodiesel and air quality

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Biodiesel and Air Quality HARC Brownbag Presentation

Rudy Smaling

November 3, 2006

"The use of vegetable oils for engine fuels may seem insignificant today.But such oils may become in the course of time as important as the

petroleum and coal tar products of the present time"

Rudolph Diesel, 1912

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Biodiesel and Air Quality - Overview

• Fundamentals

• Production

• Fuel Properties

• Engine Exhaust Emissions

• Life Cycle Analysis

• Local Policy Issues

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What is Biodiesel?

• Mono-alkyl esters of fatty acids (i.e. methyl or ethyl esters)

Oleic Acid Linoleic Acid Linolenic Acid

• Must meet the quality requirements of ASTM D6751

• Biodiesel is not unrefined vegetable oil or used cooking oil

• Typically used as a blend with petroleum diesel

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What is Biodiesel Often Claimed to be?Biodiesel is a non-toxic* fully renewable* fuel produced from new or used vegetable or animal oil or fat that can be run in any* diesel engine without any* modification and is virtually sulfur free*

• Not quite non-toxic (biocides, antioxidants, process leftovers)

• Not fully renewable (methanol input, energy required to grow feedstock and process seeds and oils)

• Not in any diesel engine (only up to up to B5 – B20)

• Not without modifications (fuel injection system and controls, no natural rubbers, different maintenance schedule)

• Biodiesel lifecycle SO2 emissions are comparable to petroleum diesel lifecycle SO2 emissions

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Biodiesel is a Renewable Fuel, Although…

• Many lifecycle analyses (LCA) show that biodiesel is a largely renewable fuel

• NREL studies found that it takes 0.31MJ of fossil energy to generate 1 MJ of biodiesel energy, similar figures have been reported from other sources

• A more recent LCA1 suggests that it takes 1.08-1.32 MJ of fossil energy input for every 1MJ of biodiesel energy

• Higher energy inputs into Soy agriculture• Electricity, herbicides, machinery, fuel, fertilizers, lime,…

• Still considered far more energy efficient than ethanol

1Pimentel, D., T.W. Patzek, 2005

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Biodiesel Delivery Infrastructure

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Typical Oil Crop Yields

Crop kg oil/ha litres oil/ha lbs oil/acre US

gal/acrecorn (maize) 145 172 129 18cotton 273 325 244 35hemp 305 363 272 39soybean 375 446 335 48linseed (flax) 402 478 359 51pumpkin seed 449 534 401 57mustard seed 481 572 430 61camelina 490 583 438 62sesame 585 696 522 74safflower 655 779 585 83rice 696 828 622 88sunflowers 800 952 714 102cocoa (cacao) 863 1026 771 110peanuts 890 1059 795 113opium poppy 978 1163 873 124rapeseed 1000 1190 893 127olives 1019 1212 910 129castor beans 1188 1413 1061 151pecan nuts 1505 1791 1344 191jojoba 1528 1818 1365 194jatropha 1590 1892 1420 202macadamia nuts 1887 2246 1685 240brazil nuts 2010 2392 1795 255avocado 2217 2638 1980 282coconut 2260 2689 2018 287oil palm 5000 5950 4465 635

http://www.Journeytoforever.org

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Some of the (Texas) Air Quality Concerns

• An additional 5 million acres of land is required to grow feedstock to feed Texas biodiesel production plants

• 200,000,000 gallon current and planned production capacity• Average Soy crop yield of 48 gallons/acre• Resulting agricultural emissions? Water Use? Fertilizer? Etc…

• Most of the Texas production facilities are located (or locating) in non-attainment areas

• Significant emissions added to non-attainment areas?

• In-use emissions of most pollutants will decrease with biodiesel• Significant reductions of PM, HC, and CO• Considerable uncertainty regarding NOx

• Little (relevant) data compared to TxLED baseline fuel

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• Fundamentals

• Production

• Fuel Properties




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Methanol Recovery

Dilute AcidEsterification

Transesterification

Glycerin Refining Refining

Crude BiodieselCrude Glycerin

BiodieselGlycerin

Methanol + KOH

Sulfuric Acid+ Methanol

Recycled GreasesVegetable Oils

Basic Biodiesel Production Process

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Rapeseed Oil to Rapeseed Methyl Ester (RME)

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BiodieselProject.gvp

Making Biodiesel is Easy…Too Easy?

• Biodiesel is extremely easy to make:• Obtain clean oil (any vegetable or animal oil)• Add Methanol and Lye (KOH)• Stir and wait for glycerin to settle• Pour off “biodiesel”

• Many small-batch biodiesel producers around that give biodiesel a bad name

• Poor quality, consistency, etc…

• This has led to the BQ9000 certification

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Biodiesel Processing Mass Balance

Input

• Virgin oil 1000 kg

• Potassium Hydroxide 9.3 kg

• Methanol 140 kg

• Total Input 1149.3 kg

Output

• Biodiesel 942.4 kg

• Glycerin + Impurities 206.9 kg

• Total output 1149.3 kg

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Annual Biodiesel Production

• 2006 annual biodiesel productionis estimated at 250M gallons

• 2006 annual biodiesel production capacity is 580M gallons

• 2007 annual biodiesel production capacity is planned to be 1.4B gallons

• 2005 annual petroleum diesel production was 49B gallons• Biodiesel share of total diesel production is 0.15%• Projected to grow to 0.5% in 2006

• Assuming representative crop yields (50 gal/acre):• 2006 biodiesel production requires 7,812 sq miles of crop land (~NJ)• 2006 biodiesel capacity requires 18,125 sq miles of crop land (~WV)• 2007 estimated capacity requires 43,750 sq miles of crop land (~OH)• Complete displacement of petroleum diesel requires 1.54M sq miles (~6X TX)

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Current Biodiesel Production Plants September 13, 2006

• US total 2006 biodiesel production capacity is ~580,000,000 gallons/year

• Texas: 13 plants with a combined capacity of ~100,000,000 gallons/year

National Biodiesel Board

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Biodiesel Plants Under Construction September 12, 2006

• 2007 US biodiesel production capacity estimated to be ~ 1.4B gallons/year

• Texas: 9 plants with a combined capacity of ~100,000,000 gallons/year

National Biodiesel Board

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Texas Ozone Non-Attainment Areas

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An alternative Biodiesel?

• Nestle Oil has developed a “next generation” biodiesel

• Hydrogenation the fatty acid feedstock resulting in a HC biodiesel they call NExBTL (next generation biomas to liquids)

• The 100% paraffin fuel has superior properties compared to either ultra low sulfur diesel or biodiesel (ULSD)

• Emissions testing by Scania shows significant decreases in both PM (~25%) and NOx (~18%) compared to European ULSD

• 60,000,000 gpy plant being built in Porvoo, Finland at a cost of $125M. Fuel cost?

Nestle Oil

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• Fundamentals

• Production

• Fuel Properties




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Definitions

• Cloud Point: Temperature at which fine crystals are first visually observed as the fuel is cooled

• Cold Filter Plug Point: Temperature at which enough crystals have agglomerated to plug the fuel filter

• Cetane number: A measure of a fuel's willingness to ignite when it's compressed. Higher Cetane number indicates a greater willingness to ignite

• Iodine Value: A measure of the level of saturation of the oil (m)ethyl-ester. Low Iodine Number indicates high saturation

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Oils, melting points and Iodine Values

• Iodine Value (IV) is a measure of the number of double bonds (indicating the level of saturation) in the methyl-ester molecule

• The IV is an indication of the oxidative stability of both the oil and methyl-ester of that oil

• Oxidation initially results in hydroperoxides, but can also lead to polymerization

• Iodine Value is also an indication of the melting point (or cloud point) of the oil and oil methyl-ester

• EN 14214 calls for a max. IV of 120

Approx.melting point

(deg C)Coconut oil 25 10Palm kernel oil 24 37Mutton tallow 42 40Beef tallow - 50Palm oil 35 54Olive oil -6 81Castor oil -18 85Peanut oil 3 93Rapeseed oil -10 98Cotton seed oil -1 105Sunflower oil -17 125Soybean oil -16 130Tung oil -2.5 168Linseed oil -24 178Sardine oil - 185

Oil Iodine Value


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Various Methyl Esters Cetane Number

DOE/GO-102006-2288

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Composition of Various Biodiesel Feedstocks

DOE/GO-102006-2288

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Cetane Number of Various Biodiesels

DOE/GO-102006-2288

TxLED requires a minimum Cetane number of 48

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In Summary

• Good cold flow properties require a highly unsaturated biodiesel fuel

• Combustion performance, fuel oxidation and polimerization are problems

• Fuel stability and good combustion require a highly saturated biodiesel fuel

• Viscous or solid at low temperatures

• However, local Biodiesel properties are driven by regionally available feedstocks

• Reality results in a compromise fuel

• Fuel additives may be a solution, but Cetane enhancers have shown little effect on newer engines

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NExBTL Holds Promise…But at What Cost?

Nestle Oil

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National Standards for Biodiesel- Europe Austria

Czech Republic France Germany Italy Sweden USA Australia

Application FAME FAME RME VOME FAME VOME VOME FAMAE -

Viscos. 40°C mm2/s 3.5-5.0 3.5-5.0 3.5-5.0 3.5-5.0 3.5-5.0 3.5-5.0 3.5-5.0 1.9-6.0 3.5-5.0

Flashpoint °C >120 >100 >110 >100 >110 >100 >100 >130 >120

Total contam. mg/kg <24 - <24 - <20 - <20 - <24hrs;110°C 6 hours min - - - - - - - 6 hours minCetane No. >51 >49 >48 >49 >49 - >48 >47 >51

Iodine No. <120 <120 - <115 <115 - <125 - -

Ester cont. % mass

Standard/specification

Methanol % mass

Density 15°C g/cm

Distillat. 95%°C

CFPP °C(cold filter plug

<10 mg/kgSulfur % mass <10 mg/kg<0.05% vol

Jan-02

<0.05<0.001<0.01<0.01-<0.02<0.02

Free glycerol% mass

Phosphor mg/kg <10 <20 <20 <10 <10 <10 <10<0.001%

mass <10

<0.02<0.02 <0.05 <0.02 <0.02<0.02 <0.02 <0.02 <0.02

>96.5- >98 >98 ->96.5 - - >96.5<0.20 <0.20 - <0.1 <0.3 <0.2 <0.2 - <0.2

<0.05% vol.<200 <300 <700 <300Water mg/kg <500 - <500

<360

*country specific 0/-15 -5 - 0/-10/-20 - -5 - -

- <360 -90% @ 360°C- - - <360

Sep-03

0.86 -0.90 0.85 - 0.89 0.87 - 0.89 0.87 - 0.90 0.875 - 0.90 0.86 -0.90 0.87 - 0.90 -860 to 890

kg/m3

Sep-97 Sep-97 Apr-97 Nov-96Date 2003 Jul-97 Sep-98EN 14214 ON C1191 CSN 65 6507

Journal Officiel DIN V 51606 UNI 10635 SS 155436

ASTM D-6751

Fuel Std. (Biodiesel)


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US Fuel Quality Specifications

• ASTM D6751 Specification for B100 for Blending currently being modified to:

• Generally tighten the specification and improve quality• Address stability concerns of OEMs• Ensure compatibility with 2007/2010 diesel technology

• B20 finished fuel specification in progress• Users, OEMs want B20 specification ASAP• Recently balloted at ASTM -failed on lack of oxidation stability spec. for B20

• Additional research is required to define test methods and specification limits

• Limiting factor is lack of data relating fuel stability, fuel stability test results, and deposit formation in engines

• Limits added recently for calcium and magnesium (ASTM D-6751-06a)

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Potential Fuel Injection Equipment FailuresFuel Characteristic Effect Failure Mode

Fatty acid methyl esters (general)Causes some elastomers including nitrile rubbers to soften, swell, or harden and Fuel leakageCorrodes aluminum & zincLow flash pointPotassium and sodium compoundsSolid particles

Dissolved water in biodiesel Reversion of biodiesel to fatty acid Filter pluggingCorrosion Corrosion of FIESustains bacteria SludgingIncreases the electrical conductivity of fuelCorrodes non ferrous metals Filter cloggingSoaks cellulose filtersSediments on moving parts and lacquering Injector cokingProvides an electrolyte and hastens the corrosion of zinc Corrosion of FIESalts of organic acids Filter pluggingOrganic compounds formed Sediments on parts

Higher modulus of elasticity Increases injection pressure Potential of reduced service lifeGenerates excessive heat locally in rotary distributor pumps Pump seizuresHigher stressed components Early life failures

Poor nozzle spray atomizationSolid impurities Potential lubricity problems Reduced service life

Corrosive acids (formic & acetic) Corrodes all metallic parts Corrosion of FIEHigher molecular organic acids Similar to fatty acid

Filter pluggingLacquering formation in hot areas

Aging products

Polymerization products Deposits especially from fuel mixes

Free water in mixtures

Free glycerin, mono- & di-glyceride

Free fatty acid

High viscosity at low temperature

Free methanol in biodiesel Corrosion of FIE

Biodiesel process chemicals Blocked nozzles

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• Fundamentals

• Production

• Fuel Properties




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Criteria Pollutant Emissions Effects

EPA

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Particulate Matter PM Emissions

• Testing performed with a CCRT paticulate filter

• Balance Point Temperature (BPT) significantly lower for B100

• Cert fuel: ~360 C• B20: ~320 C• B100: ~250 C

• The lower BPT is thought to be responsible for higher DPF regeneration rates

• This explains the additional PM reductions in a CCRT + B20 combination

NREL Milestone report: NREL/TP-540-39606

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Potential for Future PM Reductions

• Increased fuel consumption for biodiesel lies around 2-3% for a B20 blend, commensurate with the lower energy content of the biodiesel

• Total fuel penalty for a DPF + B20 combination ~ 5%

• However, many HD truck have mild duty cycles resulting in low exhaust temperatures requiring active PM regeneration, with fuel penalties approaching 10%

• A biodiesel fuel (B20-B100) may allow the use of passive PM filter systems where active systems would otherwise be required

• Additional savings can be obtained from optimized filter designs for dedicated biodiesel applications

NREL Milestone report: NREL/TP-540-39606

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Comparison of Data to Basic NOx Correlation

• EPA compiled and studied a large dataset of biodiesel tests

• Study published in 2002 covered only older engines

• All testing was engine dynamometer based

• The data shows significant scatter in the NOx results

• Unsure whether averaging the data was appropriate given that the feedstock, test engines, and test protocols were not representative

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Composition of Various Biodiesel Feedstocks

DOE/GO-102006-2288

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NOx From Single Types of Methyl Esters

DOE/GO-102006-2288

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NOx Emissions From Various B100 Fuels

DOE/GO-102006-2288

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Biodiesel Composition effects on NOx

• Reiterates previous slides: higher un-saturation results in higher NOxemissions

• For a B20 blend, a NOx neutral Iodine Value lies around 95 (based on the EPA biodiesel database)

• This suggests that higher and lower I.V. fuels may be a strategy to eliminate the NOx increase in older engines

NREL

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Biodiesel NOx Engine Effect

• It is speculated that the higher bulk modulus for biodiesel fuel causes more rapid needle lift in the fuel injector, advancing fuel injection timing, this effect is larger in newer (higher pressure) fuel injection systems

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Biodiesel Bus Chassis Dynamometer Testing

• B20 vs. conventional diesel fuel• In-use buses tested (40,000 lb

GVWR)• City Suburban Heavy Vehicle Cycle

(CSHVC) at 35,000 lb inertia• Cummins ISM 2000 Engine –No

EGR

• Expected reductions (g/mile basis)• PM ≈18%• HC ≈29%• CO ≈24%• Fuel Economy ≈3%

• Unexpected reductions in NOx• 4% reduction• statistical confidence > 99%

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Comparison of engine and Vehicle Emissions

• EPA predictive model based on engine dynamometer data

• Model results compared here to vehicle (chassis dynamometer) test results

• On average NOx is reduced in vehicle testing

• The bottom line on biodiesel and NOx:

• There are insufficient data, and insufficiently representative data, to draw any conclusions regarding the average effect of biodiesel on NOx emissions, even directionally

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NExBTL Shows Significant NOx and PM Reductions

Scania

All testing on Scania Euro 4 engines

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Aggregate Toxics Effect of Biodiesel

From a USEPA study:

• Formaldehyde and acetaldehyde emissions from biodiesel are 30% lower than from petroleum diesel

• PAH and NPAH emissions are reduced by more than 85%

From a European study (Institute of Biosystems Engineering):

• Formaldehyde emissions can be anywhere from -10% to +50% compared to petroleum diesel (seems test method dependent)

• Shows far smaller decreases in PAH emissions (5-50%)

USEPA Institute of Biosystems Engineering, Federal AgriculturalResearch Centre, Braunschweig, Germany

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More Detailed Toxics Data

• Available toxics data evaluating effects of biodiesel provides few answers

• Quantitative effects are inconclusive as are directional effects

Correlation of % change in toxics with % biodiesel% change in toxics = c × (% biodiesel) × 100%

EPA420-P-02-001Institute of Biosystems Engineering, Federal AgriculturalResearch Centre, Braunschweig, Germany

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Effects on Emissions Control Systems

• Effect on Diesel Particulate Filter (DPF) performance is very positive

• Data shows that biodiesel soot is more reactive, contains oxygen, is less carbonaceous with a higher soluble organic fraction

• Filter regenerates at lower temperatures at greater rates

• Some concern exists regarding process chemicals Calcium, Potassium, Sodium, and Magnesium

• These chemicals can negatively affect ceramic substrate durability

• No data is available at all for biodiesel fuel effects on NOx emissions control technologies such as Selective Catalytic Reduction, Lean NOx Catalysts, or NOx traps

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• Fundamentals

• Production

• Fuel Properties




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Lifecycle Air Emissions for Biodiesel(gr/bhp.hr)

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Lifecycle Air Emissions for Petroleum Diesel(gr/bhp.hr)

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Lifecycle Air Emissions comparison (gr/bhp.hr)

N2O

Lifecycle Air EmissionsProduction Cycle Air Emissions

Excluding Foreign Emissions

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

NH3 CO10

00*F

ormald

ehyd

e

NMHC

NOx

100x

N2O

10xP

M10 SOx

PetroleumBiodiesel

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Ecological Effects of RME Substitution

IFEU – Institut für Energie- und Umweltforschung Heidelberg, Germany

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Biodiesel Lifecycle Emissions Summary• On a lifecycle basis:

• CH4, SOx, HF, PM, and CO are positively affected

• NOx, HCL, HC, and NH3 are negatively affected

• Analyzing data can be difficult• National averages assumed• Specific case study for Chicago was

presented showing additional advantages from the national average

• Studying the Texas case would be of value

• Texas is the largest biodiesel producer• Mostly using imported feedstocks• Unique electric grid

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Net CO2 Life Cycle Emissions

• This analysis is for biodiesel derived from Soybeans

• B100 emits 10% more CO2at the tailpipe compared to petroleum diesel

• B100 emits 78% less CO2based on non-renewable sources only

• These numbers depend on many assumptions!

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Various Tax and Other Credits

• Biodiesel or ethanol blended with taxable diesel, that is identified when sold or used as a biodiesel or ethanol fuel blend, is exempt from the diesel fuel tax. (Reference Texas Statutes, Tax Code, Sections 162.001 and 162.204)

• Blender credit of $0.01 per percent biodiesel blended into petroleum diesel

• Some concerns: reports that some fleets are blending their own B99 fuel to get the maximum credit without regard for engine durability effects

• Another reported loophole: some companies import cheap palm oil, blend in some petroleum and sell off to foreign markets…

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• Fundamentals

• Production

• Fuel Properties




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Texas Fuel Specification Rule• Texas implemented requirements for a Texas Low

Emissions Diesel fuel formulation (TxLED)

• Must contain less than 10% aromatics and have a cetane number of at least 48 (compared to 40 for EPA #2 diesel and 50 for CARB spec low sulfur diesel)

• Impacts only the non- and near-non-attainment areas in Texas

• Any biodiesel or biodiesel blend must meet these same specs or cannot be sold or used in the affected counties

• In fact, biodiesel (blends) must not emit more NOx than TxLED certified fuels

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So What’s the Issue?

• Texas is the largest biodiesel producer in the nation with production facilities near HGA and DFW

• AG and Energy industries and petroleum independence advocates all want biodiesel for various reasons

• TCEQ is responsible for meeting air quality targets and is putting on the brakes…

• Old data suggests NOx increases• Old data based on engine based testing which is still both a TCEQ, EPA, and

CARB requirement• New data from vehicle based testing shows decreases in NOx, however there

are no vehicle based test protocols (yet)

• TCEQ (Mr. Shanbacher) on record saying “proper science and supporting data is lacking to make a decision for biodiesel”

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What can/should HARC do?

• Data, data, data

• Impact of biodiesel production in the (near) non-attainment areas?

• What if a B5 or B20 would be allowed in all of Texas?• What feedstocks? Additional fuel specs?• NOx emissions? Ozone forming potential?• Vehicle based test protocols (same issue with Hybrids, any synergies?)

• Planning a biodiesel workshop to develop a scope of work that may allow us to answer these questions through modeling

• The question is: what model inputs are required and how do we obtain that required data?

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Questions?

biodiesel and air quality

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