Estimating the cetane number of WVO and (pure)gasoline blend

[tillyfromparadise]

Hi Tony,
I checked the wayback machine and biodiesel discussion.com was the Infopop forum.
In my original post I said it came from the infopop forum. I have done a wayback machine search and found a copy of the post he made a few days later later on the infopop forum here https://web.archive.org/web/20080517...51/m/155102319 It is the sixth post down but the date is different from the one I posted.

This has piqued my interest. I will try to find his post dated 27/5/2005 which was the one I copied.

[Tony From West Oz]

Tilly, The forum you linked to was http://www.biodieseldiscussion.com, which, like the Infopop forum as also disappeared.

[tillyfromparadise]

Hi Tony,
That is the post I was referring to. I didn't remember I had posted it here. So much information was lost when the infopop forum closed. A tragedy.
Tilly

[Tony From West Oz]

Tilly, here is a post you posted on some time ago about the impact of petrol on Cetane number


https://www.biofuelsforum.com/forum/...7549#post87549


\
Unfortunately, the linked forum in that post is defunct and content has disappeared into the ether, but thankfully Tilly posted the content of that post on this forum for posterity.
Tony

[magnusson]

Re: Estimating the cetane number of WVO and (pure)gasoline blend

Thanks Tony and Tilly, I'll do the test when I get back home from school in a few months and will update the thread.
Cheers

[tillyfromparadise]

Re: Estimating the cetane number of WVO and (pure)gasoline blend

Hi magnusson,
I can not answer your question.
In my early days of biodieseling/blending, when I did not know the answer to something I wanted to know, I would do some testing to find out.

If I were you, I would do the following test:
1. Place 500ml of the cleaned, transparent canola you plan on using in a freezer with a thermometer in it to find it's cloud point. Check and stir often. Cloud point is where the transparent canola oil turns translucent- it starts to turn cloudy. Write down this temperature.
In my view, you really do not want to go colder than this temperature.
2. Warm the oil until it turns transparent again. Add 15% UPL (Un Leaded Petrol without ethanol) and mix thoroughly. Place in a freezer with a thermometer in it to find it's cloud point. Check and stir often. When it starts to cloud write down the temperature.

When you have both numbers written down you will have the answer to your question.
Please come back to the forum and tell us what your testing showed. That is how we advance.
I hope you have an understanding wife.

Hooroo, Tilly

[Tony From West Oz]

Re: Estimating the cetane number of WVO and (pure)gasoline blend

Sorry for the late reply. I was thinking of using this mix in a 2002 volkswagen golf tdi with the ALH engine code. That's really fascinating that the cetane increases with reduced viscosity, do you know if the freezing temperature is also a linear relationship?

I do not think that the solidification point of vegetable oils would vary significantly with the addition of ULP. You are not chemically changing the triglyceride molecules, just adding another liquid to the fuel tank.
Oils which solidify at the minimum temperatures experienced, would require heated fuel systems so that the fuel can still flow thru the fuel pipes, filters, and pumps. If this cannot be factored into your conversion, I recommend that you only use fuels which do not solidify at these temperatures.

Tony

[magnusson]

Re: Estimating the cetane number of WVO and (pure)gasoline blend

Sorry for the late reply. I was thinking of using this mix in a 2002 volkswagen golf tdi with the ALH engine code. That's really fascinating that the cetane increases with reduced viscosity, do you know if the freezing temperature is also a linear relationship?

[tillyfromparadise]

Re: Estimating the cetane number of WVO and (pure)gasoline blend

Hi magnusson,
Welcome to the forum.
A quick google shows the cetane of petrol is 15- 20 and rapeseed is 41.6. Papers I have read says the relationship is linear.
So a cetane of 37.61 to 38.36 would seem to be expected.
HOWEVER, as I recall, many years ago on a biodiesel forum that has long since disappeared, there was a petroleum chemist who explained that adding petrol to veg oil reduces the viscosity. This reduced viscosity will increase the cetane more than if the two liquids were of a similar viscosity.

What do you plan on using this fuel in?

[magnusson]

According to this study the cetane of rapeseed oil is 41.6 https://www.researchgate.net/figure/...tbl1_343203947
The cetane of gasoline is 0 I think. If I run an 85% to 15% blend, would the cetane be 85% of 41.6?
So 35.36? Or is the relationship not so linear?