Biodiesel as a Boiler Fuel

Over the past few years, biodiesel has gained popularity for it’s use as an alternative fuel in home heating oil and boilers.   In North QuickShot 2012.11.09 at 11.34.53Carolina, biodiesel has received interest from off-road farm, quarry, and industrial boiler customers because of biodiesel’s reduced particulate content and reduced sulfur.

Some customers just want a cleaner burning fuel (or fuel blend, some customers are blending biodiesel with regular off-road diesel, still lowering emissions), other customers are being required by the EPA, DENR, internal environmental policies, or even OSHA.

Regardless, biodiesel has been shown to be highly compatible with existing offroad equipment and stationary burners, and has proven to significantly reduce sulfur, ash, soot, and carbon monoxide output from these systems.

What’s better, is that most biodiesel made in North Carolina is either from locally grown soybeans or from used cooking oil, recycled into a clean burning, domestically produced diesel fuel alternative.

What Happens to My Used Cooking OIl

Biodiesel Plants in North Carolina

The biodiesel industry has faced uncertain times since 2008, with government mandates and subsidies being unpredictable at times.  Some biodiesel plants have gone idle or out of business permanently because of this instability, but North Carolina remains a strong state for renewable energy.

There are five active biodiesel plants in North Carolina:

  1. Triangle Biofuels Industries – Wilson, NC
  2. Blue Ridge Biofuels – Asheville, NC
  3. Patriot Biodiesel – Greensboro, NC
  4. Foothills Bio-Energies – Lenoir, NC
  5. Piedmont Biofuels – Pittsboro, NC

 

A Firefighter’s Guide to Biodiesel

After numerous articles in the media about small (and sometimes large) fires at biodiesel plants, most of the articles I read end up saying something about how the fire department was ill-prepared or unsure about what chemicals were in the plant and whether they were hazardous.  In some cases, they even questioned whether the biodiesel itself was hazardous.   I’m not a firefighting expert, nor a chemist, but I’m going to attempt to explain in layman’s terms what can be found at the typical biodiesel plant and a little bit about each.

  1. Vegetable Oil – Health:1, Fire:1, Reactivity:1. Any type oil, soybean, canola, waste vegetable.  These oils are non-hazardous, non-toxic, and non-flammable.  Flash point is well over 450°F.   Most biodiesel plants will store vegetable oil in bulk tanks, but it may also be found in 300 gal IBC totes.  Treat as oil fire.   Foam, dry chemical, CO2, or water if necessary.  Water on oil fires is a last resort, as it tends to spread the oil (and thus the fire), and in some cases can actually flash to steam and create a more dangerous situation.  Potential fire sources in biodiesel plants are caused by using electric heating elements directly exposed to vegetable oil with lack of stirring or overheating.
  2. Biodiesel – Health:1, Fire:1, Reactivity:1. Chemical name Mono-Alkyl Ester.  Non-hazardous, non-toxic, and non-flammable.  CAS Number 67784-80-9.  Flash point typically over 300°F.   Treat as oil fire.   Foam, dry chemical, CO2, or water if necessary.  Use water spray, fog or foam. Do not use water jet.  Water on oil fires is a last resort, as it tends to spread the oil (and thus the fire), and in some cases can actually flash to steam and create a more dangerous situation.  Disbursement into ravines or water sources can be immediately threatening to wildlife in some cases (oil film on water surface, oxygen reducer), but researchers at the University of Idaho noted that after leaving biodiesel in an aqueous solution for twenty-eight days, ninety-five percent of biodiesel was gone—completely degraded.   Potential fire sources in biodiesel plants are caused by using electric heating elements directly exposed to biodiesel with lack of stirring or overheating.  In certain cases (in process biodiesel production) methanol may be added to the biodiesel, reducing the flash point and making a hazardous material.
  3. Glycerin –  Health:1, Fire:1, Reactivity:0. Chemical name propane-1,2,3-triol.  CAS Number: 8043-29-6.  Pure glycerin is a non-flammable and non-hazardous material.  Depending upon the feestock and purity, it can contain methanol, lipids (vegetable oil), and water.  In these cases the material may be considered slightly hazardous and flammable.  It is slightly hazardous in case of skin contact (irritant, permeator over long contact duration), of eye contact (irritant), of ingestion, of inhalation.  Flash point for pure glycerin is 320°F, but methylated glycerin can be much lower.   Most biodiesel plans will have both raw (with methanol) and finished (pure or near pure) glycerin.  All but refined glycerin will have a brownish to dark black color and syrup like viscosity.   It may be stored in barrels, 300 gallon IBC totes, or in bulk tanks.   Treat as oil fire.   Foam, dry chemical, CO2, or water if necessary.  Use water spray, fog or foam. Do not use water jet.  Glycerin is heavier than water and runoff into ditches, streams, and ponds may not be immediately visible because the material may be on the bottom.
  4. Methanol Health:3, Fire:3, Reactivity:1.  Chemical name: Methyl Alcohol.  CAS Number: 67-56-1.   Methanol is highly flammable, toxic, and hazardous.  It burns with a light blue flame, almost invisible during daylight.   Flash point is 54°F.  Most biodiesel plants will have pure methanol.  It may be stored in barrels, 300 IBC gallon totes, or bulk tanks.  Treat as oil fire.   Foam, dry chemical, CO2, or water if necessary.  Use water spray, fog or foam. Do not use water jet.  All pumps and motors involved in production for methanol related materials should be explosion proof.
  5. Sodium Methoxide or Sodium Methylate –  Health:3, Fire:3, Reactivity:3.  CAS Number: 124-41-4.   Definitely the most dangerous material at a biodiesel plant.  Some biodiesel plants may use Potassium Methylate in addition or instead (treat similarly).  This material will be in liquid form, and has a clear, viscous appearance.  Flash point is 91°F.  Treat as oil fire.   Foam, dry chemical, CO2, or water if necessary.  Use water spray, fog or foam. Do not use water jet.   Highly flammable and autoignition possible in presence of moisture. Flammable in presence of open flames and sparks, or heat.   Most small to medium sized biodiesel plants have this in small quantities, usually stored in drums or 300 gal IBC totes.  Some larger plants will store this in bulk tanks, which are usually stainless steel.  This material is highly reactive, caustic, hazardous and toxic.  Avoid contact with skin, inhalation, and exposure to eyes.  Do not flush caustic residues to sewer. Residues from spills can be diluted with water, neutralized with diluted acid such as acetic and hydrochloric. Absorb neutralized caustic residues on clay, sand, vermiculite or other absorbent material and place in a chemical waste container for disposal.
  6. Sodium HydroxideHealth:3, Fire:1, Reactivity:2.  CAS number: 1310−73−2 100.  Some biodiesel plants may use Potassium Hydroxide in addition or instead (treat similarly).  Corrosive, causes severe burns.  This is a corrosive solid that has a physical appearance of white flakes or white granules.  It is highly toxic and hazardous.  It is commonly stored in drums and 55 lb plastic bags (like potting soil).  Most small to medium sized plants will have 2,000 to 10,000 lbs on hand at a time. Avoid contact with skin, inhalation, and exposure to eyes.   Sodium hydroxide is slightly toxic in the aquatic environment. The toxic effect on aquatic organism is due pH increasing.  It is soluble in water and degrades quickly.  Not considered a fire hazard; however, for large fire use powder, foam extinguishing agents or carbon dioxide. Avoid water use if possible. Adding water to caustic solution generates large amounts of heat and steam! Do not flush caustic residues to sewer. Residues from spills can be diluted with water, neutralized with diluted acid such as acetic and hydrochloric. Absorb neutralized caustic residues on clay, sand, vermiculite or other absorbent material and place in a chemical waste container for disposal.

While this is certainly not an exhaustive list of materials found at biodiesel plants, it contains the primary components that nearly every biodiesel plant in the Unites States uses on a daily basis.  Our plant is located in the city of Wilson, NC and we regularly have visits and familiarization drills with the firefighters in the town to acquaint them with the materials we use in our plant, and where they are stored.  These drills become invaluable when the need arises in order to minimize the potential danger to the firefighters and the community should disaster strike.