Safe use of absorbents to clean up biodiesel spills
At New Pig, we value everyone’s safety. Since we’ve had some blog posts about biodiesel fuel, and because we’ve been hearing from more and more customers and do-it-yourselfers who are embarking on the adventure of making biodiesel, I wanted to give some quick notes on using absorbents with biodiesel and its components.
Biodiesel, vegetable-based oils and other components of biodiesel have a tendency toward spontaneous combustion when mixed with common spill cleanup products, so whether you’re using absorbent mats, wipers, rags, paper towels, cellulose absorbents, sawdust, clay, or chicken feathers, KEEP THE SPENT, SATURATED ABSORBENTS IN CLOSED CONTAINERS.
That means sealed drums, containers with tight-sealing lids, ziplock bags with the air squeezed out … There are lots of options out there.
Keeping the container or bag sealed limits the amount of oxygen reaching the soaked absorbents and helps minimize fire risks.
Whenever possible, store saturated absorbents in areas where they are not likely to create a structure fire, and arrange for prompt disposal through proper channels. Your local solid or hazardous waste authority should be able to offer suitable methods for proper disposal. If not, give Safety-Kleen a call.
Note that PIG® Absorbent Mats are made of 100% polypropylene and our PIG® BLUE Absorbent Socks have a polypropylene skin and vermiculite filler. Neither polypropylene nor vermiculite will support combustion. However, that doesn’t mean that absorbing something into them makes the resulting mixture safe.
Absorbents – ours and everyone else’s – take on the properties of the liquids that they absorb, so if you absorb a flammable liquid or one prone to spontaneous combustion into absorbents, you need to store, handle and dispose of the absorbents with the same precautions as the liquid.
In the case of hazardous materials, that means closed containers. New Pig offers open-head funnels and latching drum lids that can help facilitate quick, easy handling of wastes stored in steel drums. We also have products to help you safely collect and store liquid wastes. All are designed for ease of use and will help your facility stay cleaner and safer.
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August 27th, 2009 at 8:39 am
Thanks for the question, Robert. I’ll make sure the post author, Karen, or someone else from New Pig Tech sees this and replies ASAP.
August 27th, 2009 at 10:43 am
Great question, Robert! Thank you for posting it!
Please note that heat isn’t generated by the cleanup process – it actually generates post-cleanup.
Without getting into “drying oils” versus “non-drying oils’ and iodine numbers; the simple scientific answer is that some veggie oils and bio-diesel oxidize; and the process of oxidization generates heat.
When there is a pile of oil-soaked “stuff” sitting somewhere oxidizing and the heat can’t dissipate; it builds up – which speeds up oxidization and generates even more heat. When the oil reaches its auto-ignition temperature (the point where it bursts into flames without an external ignition source) spontaneous combustion happens.
This reaction can occur at ambient temperatures. It doesn’t need to be a super-hot day for this to happen -although, that, of course, can make the reaction occur “sooner” rather than “later.”
That’s also why it doesn’t matter what type of absorbent you use – it is the nature of the oil, not the absorbent, that is causing the spontaneous combustion.
Many people have heard or seen news stories of do-it-yourselfers using linseed oil to seal a deck or piece of furniture and tossing the oil-soaked rags in a pile in their garage only to have a fire in the garage that evening or within the next day or two.
To help prevent this, many organizations recommend spreading the rags out to dry – the increased surface area causes the heat from the oxidization process to dissipate more quickly so that it doesn’t build up to dangerous levels – or keeping the soaked rags in a tightly sealed container. Fires need oxygen. No oxygen: no fire.
In a spill response situation, things are a bit different than sealing a deck: it’s often not a good (or safe) idea to lay things out to dry; but it is usually possible to keep spent sorbents in a closed container and out of the heat to increase safety.
I hope this helps! Thanks again for the question!