TECHNICAL

Biodiesel is produced by the reaction of a vegetable oil or animal fat with an alcohol (typically methanol) in the presence of a catalyst to yield mono-alkyl esters (biodiesel) and glycerin (~10% by weight). This reaction is called transesterification. Raw or refined vegetable oil or recycled greases that have not been processed into biodiesel are not biodiesel.

One of biodiesel’s advantages is that it can be used in unmodified diesel engines and with little or no change to fuelling infrastructure. Biodiesel has a higher cetane number than most diesel fuel, allowing it to provide similar fuel consumption, horsepower, torque, and haulage rates as fossil diesel fuel. Hundreds of millions of on-road kilometers and countless marine and off-road applications as well as extensive studies have demonstrated biodiesel’s power and efficiency across the full range of duty cycles and applications.

Numerous tests of biodiesel and petroleum diesel show the distinct improvement in lubricity when biodiesel is added to conventional diesel fuel, above the additized level in all commercially available diesel. Ultra Low Sulphur Diesel has poor lubricity, and is heavily additized with lubricity conditioners. Biodiesel blends as low as one percent can provide up to a 65 percent increase in lubricity in distillate fuels and help prevent premature engine component deterioration. The increased lubricity of biodiesel is associated with a noticeable decrease in engine noise in some applications.

Blends of B20 or lower have not exhibited elastomer degradation and have been widely shown to be compatible with all engines. Biodiesel contact with natural or butyl rubber components (primarily fuel hoses and pump seals) is not recommended in excess of B20 blends in engines older than 2004. Certain elastomers soften and degrade with prolonged exposure to higher levels of biodiesel.

Like regular diesel fuel, biodiesel blends can gel at very low temperatures. The composition and cold flow properties of diesel fuels vary widely across Canada. Very low levels of methyl ester (ME) can be accommodated in any diesel fuel in Canada. The amount (%) of biodiesel will depend on factors such as the time of year, location, diesel and biodiesel properties (including cloud point).

The cold flow properties of B20 or higher biodiesel blends can vary appreciably based on the feedstock from which they are made. In general, the better the cold flow characteristics of the base diesel fuel, the greater the effect of blending biodiesel on its cold flow properties. Mid-level (up to 20%) blends can be used seasonally in most parts of Canada.

Diesel and biodiesel blends are both placed into the market with ‘fit for use’ assumptions that anticipate probable use, including delays between purchase and use and travel by the fuel user to a colder region.

The low temperature operability of ULSD in Canada is typically achieved by refining a winter diesel, with limited use of kerosene and additives such as pour point depressants, filterability or flow improvers, and wax anti-settling additives. Understanding the base ULSD cold weather specifications (cloud point and low temperature flow test) is a starting point in assessing the impact of biodiesel in the blended fuel. Any additives must be introduced into the diesel fuel before the fuel reaches its cloud point, and must be properly blended.

Additizing biodiesel blends to achieve expanded cold flow performance is a common practice in northern US states; Minnesota fleets blend 5% biodiesel into winter diesel in part through additization. A 2011 third-party documented demonstration of B10 blends in a large longhaul trucking fleet showed that biodiesel is a robust fuel. Biodiesel vehicles parked outside cold-started when straight diesel did not, and 10% blends with no additization or kerosene were employed through the full temperature range of an Alberta winter. Another Alberta study in 2009 showed that a B2 blend was fully compatible with an Alberta winter, performing well beyond the projected operability limit.

All major Original Equipment Manufacturers (OEM) approve the use of up to 5% biodiesel (B5) when blended with diesel fuel that meets the appropriate CGSB and ASTM standards. BQ9000 accreditation is specified by some OEMs. Cummins has approved all of its engines for 7% biodiesel blends.

Millions of diesel vehicles run mid-level blends (B6-B20) every day with full operability and billions of successful US and Canadian road miles over two decades. Engine manufacturers are full participants in developing the strict biodiesel quality standards that enable the use of blends up to 20% (B20). OEMs have been party to widespread commercial use of B11, B15 and B20 in several US states (e.g., Illinois, Minnesota) and neither they nor other stakeholders have reported any more incidence of engine or operability issues than is found with straight diesel.

Truck manufacturers have not intervened in markets to disapprove regulations and incentives for mid-level blends. Strong fuel quality oversight, and an experienced petroleum sector, has been important to mid- level blend success, including BQ9000 fuel quality accreditation and the adoption of inline biofuel blending capabilities.

OEMs express warranty approval only for models that have been tested on biodiesel blends; this is common for late-model engines. When an OEM does not express biodiesel approval for an engine, it means only that biodiesel testing has not been conducted on that engine. Manufacturers mostly do not test legacy models; they are ‘out the door’, with biodiesel testing conducted only on new models.

Lack of warranty approval is sometimes mistakenly taken to mean that an engine will not be operable above the warranted blend level or that warranties will be voided for use above the stated level. This is not accurate. Where an affirmative warranty statement has not been given, the OEM has not specifically tested that model.

A joint statement by the Oregon Auto Dealers Association and the Northwest Biofuels Association explains the Magnuson-Moss Warranty Act (MMWA) for biodiesel in the simplest terms:

“A vehicle’s warranty cannot be voided solely due to the use of biodiesel. Even if the manufacturer recommends a blend of 5% biodiesel and a customer uses a higher blend such as 20% or 99% biodiesel, this does not void the warranty. If a customer uses a blend of biodiesel that is not recommended, that in and of itself, does not void the warranty. If the biodiesel is not the cause of the engine or parts failure, the warranty must be honored (assuming the failure is not the result of another external factor).”

The term ‘blend wall’ is sometimes used to claim that a 5% biodiesel blend is the highest level that engine manufacturers will honour for their warranty”.

Warranty positions by engine manufacturers have not prevented the petroleum industry from distributing very large volumes of mid-level B6, B7, B11, B15 blends (up to B20, B50 and B99) in markets far larger than Canada. US major oil companies widely market blends >5%. There is no impediment to such mid-level blending in Canada.

(See Warranties) Hundreds of millions of miles of on-road heavy-duty fleets history in the US alone shows no adverse engine impact. One US fleet alone reported in 2010 that, “Its vehicles have accumulated more than 60 million miles using B20 without encountering biodiesel-related issues, and evaluations have demonstrated no appreciable change in fuel economy, engine wear, or driver acceptance.” And a report of 26 months of data collection on 10 commercial HD trucks running B20 for 2,035,968 miles, matched with a control group on ULSD, was supported with engine teardown analyses that “did not reveal any notable differences between the two groups.”

To quality for eligibility in renewable fuel regulations in all four western provinces, commercially available biodiesel must meet strict CGSB (Canadian General Standards Board) specifications. Updated standards were published in 2012 for B1-5, B6-20, and B100 to ensure that biodiesel produced to these standards will ensure full operability in modern diesel engines.

The US and European Union have ASTM and EN standards respectively.

U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) found that 95% of the samples from 2011-12 met ASTM International fuel quality specifications.

Used cooking oils that are non-transesterified are not biodiesel. Higher viscosities, and impurities in these unprocessed fuels, are associated with problems that may include piston ring sticking, fuel system deposits, reduced power, shorter engine life, lower fuel economy, increased exhaust emissions, plugged fuel filters and higher injection pressures. Based on these issues, ABFC has not supported the commercial application of non-CGSB or non-ASTM fuels.

The CGSB biodiesel standards (e.g., CAN/CGSB-3.520-2011 for B1-5) contain appendix guidelines for biodiesel handling and blending of biodiesel. Other sources of handling and use guidelines can be found in the Resources section.
In general, good fuel management practices for diesel fuel will ensure trouble-free use of biodiesel when blended.

  • Storage: cool, clean, dry conditions, with free water drained from storage tanks and filter housings
  • Desiccant filters may be appropriate for above-ground storage of neat or higher-level blends
  • Stability additives may be helpful for long-term storage of biodiesel
  • A guideline of maximum six month’s storage is recommended; however, oxidation stability additives can extend that period significantly, and NRCan tests in western Canada showed on-farm biodiesel on spec after two years’ storage
  • To prevent precipitation of trace components from some biodiesels, biodiesel and diesel fuel should be at least 5°C above their respective cloud points

It is preferable to accomplish a biodiesel blend using inline or injection blending. Sequential or ‘batch’ blending can result in incomplete (non-uniform) batches of product.

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What is Ethanol?

Ethanol is ethyl alcohol and is a product of the fermentation of any plant material. Ethanol is the same alcohol as in alcoholic beverages. Ethanol has the same chemical formula regardless of whether it is produced from starch- and sugar-based feedstocks, such as corn or wheat grain (as it primarily is in North America), sugar cane (as it primarily is in Brazil), or from cellulosic feedstocks (such as wood chips or crop residues).
Ethanol has a higher octane number than gasoline, providing premium blending properties. Minimum octane number requirements prevent engine knocking and ensure drivability. Low-octane gasoline is blended with 10% ethanol to attain the standard 87 octane requirement. Ethanol is the main component in high-level ethanol blends. (AFDC)

Energy Content and Mileage

Ethanol contains less energy per gallon than gasoline. Pure ethanol contains about 30% less energy than gasoline.

E10 — Much of the gasoline in Canada contains 10% ethanol. Vehicles will typically go 3% to 4% fewer miles per gallon on E10.

E15 — There is no Canadian standard for 15% blends of ethanol in gasoline, and as a result it is not retailed in Canada. In the US after 2011, the EPA began allowing the use of E15 in model year 2001 and newer gasoline vehicles. Pumps dispensing E15 must be labeled.

Vehicles will typically have 4% to 5% lower fuel efficiency on E15 than on 100% gasoline.

E85 — Flex Fuel Vehicles operating on E85 get roughly 15% to 30% fewer miles per gallon than when operating on regular gasoline, which typically contains about 10% ethanol.

Standards & Quality

CAN/CGSB-3.511-2011 Oxygenated Automotive Gasoline Containing Ethanol (E1-E10). This standard applies to four grades of oxygenated gasoline to which no lead or phosphorus compounds have been added, and in which the oxygenate consists essentially of ethanol. They are intended for use in spark ignition engines under a wide range of climatic conditions.

CAN/CGSB-3.512-2013, Automotive ethanol fuel (E50-E85). This standard has been specifically developed to help ensure acceptable vehicle operability in Canada’s cold winters. It applies to automotive fuel composed of 50 to 85% by volume denatured fuel ethanol and gasoline strictly for use in flexible fuel vehicles over a wide range of climatic conditions.

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Hydrogenated Renewable Diesel

Hydrogenation-derived renewable diesel (HDRD), also known as green diesel (EU), renewable diesel (US) or second-generation biodiesel, is the product of fats or vegetable oils—alone or blended with petroleum—refined by a hydrotreating process. HDRD meets petroleum diesel CGSB and ASTM specifications. (AFDC)

HDRD can be produced from vegetable oil; animal tallow; cooking oil residues; and other fats and vegetable oils. Producing HDRD involves hydrogenating triglycerides to remove metals and compounds with oxygen and nitrogen using existing refinery infrastructure. Dedicated hydrotreating facilities that do not use conventional petroleum can also produce HDRD.

HDRD can be substituted for or blended in any proportion with petroleum-based diesel without modifying vehicle engines or fueling infrastructure. Typically, however, operational considerations have limited HDRD blending levels to 30% in Canada. HDRD refining can produce product of varying low temperature operability, which can limit the blending levels seasonally.

Renewable natural Gas (RNG) defined as methane gas derived from organic materials and waste streams that has been produced and upgraded (also called conditioning, which removes water, carbon dioxide, hydrogen sulfide, and other trace elements) to a level that meets current natural gas pipeline specifications set out by gas utility companies, or that meets natural gas vehicle fuel standards set out by engine manufacturers.

Like conventional natural gas, RNG can be used as a transportation fuel in the form of compressed natural gas (CNG) or liquefied natural gas (LNG). RNG qualifies as an advanced biofuel under the US Renewable Fuel Standard.

There are three main sources of inputs or “feedstocks” suitable for producing RNG:

1. Agricultural and agri-food sources such as unused crop residues, animal manure and food processing waste;
2. Forestry bi-products such as wood waste generated during harvest operations;
3. Municipal solid waste and bio-solids from wastewater.

RNG can be produced from these feedstocks using either anaerobic digestion, an established technology best suited for producing RNG from relatively wet feedstock and gasification, which is a rapidly developing technology best suited for producing RNG from relatively dry feedstock.

Anaerobic digestion (AD) is a natural process of decomposition of organic materials by microbes in the absence of oxygen, in which biogas is produced. Anaerobic digestion occurs in landfills and sewage treatment and in industrial processes to convert manures, agri-food residues, industrial by-products and sorted municipal wastes to biogas.

The resulting biogas contains a much lower methane concentration than conventional natural gas and can be used on-site with minor processing for its heating value or to run an electricity generator. However, upgrading technologies are available that can produce a clean, high energy RNG suitable for direct injection into existing natural gas pipeline infrastructure and able to be mixed with conventional natural gas.

Biomass gasification is a high temperature (>500 °C) process in which organic material is converted into syngas in the presence of oxygen and/or steam. The syngas can be converted into RNG through a process called methanation and then be introduced into the natural gas pipeline infrastructure and mixed with conventional natural gas.

Gasification of coal is used on a large scale in power plants, where syngas is used as a fuel in gas turbines. Gasification of biomass material (such as wood waste) is in its development phase but progressing rapidly.

Gasification has some advantages over anaerobic digestion. First, a wider variety of non-homogeneous feedstocks that can be utilized, almost any type of organic material can be used as gasification feedstock, including forestry and agriculture residues, and sorted municipal waste. Second, the methane yield is higher. Production of methane from biogas through anaerobic digestion generally converts 20 per cent of the material while gasification, depending on the process and material utilized, can achieve from 65 per cent to 80 per cent conversion yield.

The extensive Canadian pipeline and underground gas storage network and the interchangeability of RNG with conventional natural gas means that in many cases, RNG can be introduced at its point of production, and transported and transported to the end user without a significant modification to pipeline infrastructure or to the end user’s natural gas burning equipment.

Sources: CANMET Technology Roadmap / AFDC