Diesel storage (was:RE: 24x7 Support Strategies)

Thu Jun 14 16:16:12 UTC 2007

>And what about all those diesel generators? How many of them are capable
>of running on vegetable oil rather than diesel oil? I regularly walk
>past a building in London that reeks because of the diesel fuel tanks in
>the basement. You have to wonder about the safety of storing large
>amounts of petroleum oil in the centers of major cities when vegetable
>oil is safer, and more carbon-friendly.

This is something I know about, as I home-brew 
fuel for my vehicles, and I operate a datacenter 
with backup power. ;)

The issue with straight vegetable oil is that it 
must be pre-heated to >55°C to efficiently run in 
a Diesel engine without risk of injector or 
injector pump clogging. This is not exactly 
efficient for fail-over power generation as you 
would either need to build dual-tank and heating 
systems (still storing SOME petro-Diesel AND 
losing X% of your power generation facility to 
heating your fuel in the process... a LOT of 
electricity as most backup gensets have a LOT of 
fuel around to heat up... looking outside my 
office window I see two tanks, one 19000 liters, 
the other 30,000 liters in capacity.) Or you 
would need to mix that SVO with petroleum Diesel, 
to thin it enough to run risk free... negating 
your desire to rid yourself of petrochemical risk.

This is moot in exceptionally warm climates or 
exceptionally cloud-free areas as passive solar 
could be used to store SVO at high temps. 
VO-based fuels are more likely to gel at lower 
temps than petro-fuels. Ask me how I know!

Finally, vegetable oil has long term storage 
issues of the organic sort, where it can become 
contaminated with algae, bacteria, etc.

BioDiesel, that is vegetable oil that has been 
chemically stripped of glycerines through 
transesterfication is a better suggestion to 
replace petro-Diesel in generators. It has cold 
weather and storage issues too, but generally 
performs better than SVO.

--chuck