Introduction To Waste Vegetable Oil (WVO)
Running a diesel vehicle on vegetable oil is a great idea from
both an environmental and financial perspective, but there's an
even greener option available if instead of using shop-bought,
fresh, virgin oil, you use Waste Vegetable Oil (WVO) to fuel your
engine.
What is WVO?
Waste Vegetable Oil (WVO) is second hand, already used veg oil
that is no longer suitable for its original purpose. It's a waste
product
produced
within the catering industry. Wherever deep frying takes place
on a commercial basis, you're likely to find used veg oil, such
as pubs, restaurants, hotels, chip shops, etc. Once
they've cooked
with it a few times, the oil becomes dirty and tainted, so fresh
oil is required. The old oil then becomes a waste product - a nuisance.
Waste Product
From my personal experience, I've found that larger organisations
(such as Hotel chains, Brewery Owned Pubs, etc) already have an
infrastructure in place to deal with their WVO, so obtaining used
veg oil from these places is difficult. However, smaller establishments
don't have such infrastructures (independent pubs, local restaurants,
family run hotels, etc). For these people WVO is usually something
they are keen to get rid of.
Obtaining WVO
In days of old,
such companies would have paid people to take away their WVO. With
the advent of Biodiesel, etc, it's become
more common for WVO to be given away. In fact more commonly it
seems that you now have to buy WVO, which is great news for the
businesses
and bad news for the thrifty green motorist.
Personally I have some suppliers who gladly give me their
WVO just to get it out of the way, but for the most part I have
to pay for it. The rate varies according to the haggling skills
of those involved but again, from my experience, the value is usually
somewhere between 20% and 40% of the current price of shop bought
virgin oil. The reason it's cheaper than pure oil is because you
CANNOT just pour it straight into the tank of your vehicle - it
needs cleaning first. Plus it's not all usuable fuel...
Problems With WVO
The problem with WVO is that it's a dirty product. It's full of
food particles, fats, water and all manner of nasties. These must
be removed from the WVO before it's clean enough to use in your
vehicle and the cleaning process is time-consuming. Depending on
the quality of the used oil, you can often find that up to 50%
of the waste oil collected is unusable as a fuel...
Cleaning / Filtering WVO
Waste Veg Oil (WVO) must be cleaned before it's used (click
here for a little story that you may find interesting). It is cleaned
by filtering out all of the impurities that are within the oil.
Typically there are two main methods:
- Mechanical Filtration : This tends to involve
a number of pumps, storage tanks and filters. Oil is driven through
varying
filters usually to a finished level of 5 microns.
- Settling : Here WVO is roughly filtered (usually
to around 100 microns) before being left to settle for a few
weeks. As
the oil settles, the heavy fats and water fall to the bottom
of the tank and some light impurities rise to the surface. The
cleaner
oil
is then usually filtered through socks to 5 microns.
My Prefrence
Personally I favour the Settling
Method. This is certainly much less costly than
buying several pumps and filter media, but it does take a while.
If you want to read more on how I filter my oil, click
here.
Into The Tank
Once the WVO has been cleaned, it's ready to use. It may not be
the best thing to cook your chips in, but it runs a diesel engine
just as well as fresh virgin oil. For me it's a fantastic example
of recycling - taking a waste product and making it useful.
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