Blend before adding to tank, or in the tank

[dagwill Senior Member Find all posts View Profile Close dagwill]

Had a bit of a search but couldnt find anything. Is it best to blend in a separate tank to be sure all is well mixed before adding to fuel tank, or do blenders simply put say 60 ltrs of wco into their tank, go down the servo and add 6 ltrs of ULP. Drive off care free?????
Is a couple of sways side to side enough to mix WVO and ULP ?????

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Blend before adding to tank, or in the tank

I have never pre-mixed my blends. I just add oil to the tank, then add my 5L of old ULP (or, recently ULP/Diesel misfuel).
In my case this is of no consequence, as the 2 vehicles I have been using veggie in are happy with 100% veggie in the engine.

Regards,
Tony

[oz.Merv Junior Member Find all posts View Profile Close oz.Merv]

Re: Blend before adding to tank, or in the tank

I'm with Tony... Only 100% SVO. But I use twin tanks... But only purge at night or its its going to be sitting for over 3 hours.

-Merv

[Alga Senior Member Find all posts View Profile Close Alga]

Re: Blend before adding to tank, or in the tank

I'm the same if I need to blend during winter, put the oil in and add 10% diesel or BD. It's a very simple process and will be mixed before you get 2 klms. Still can understand why people use petrol for blending, when it has detrimental properties for a diesel engine compared to straight diesel in a blend, as It's so illogical.

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Blend before adding to tank, or in the tank

I'm the same if I need to blend during winter, put the oil in and add 10% diesel or BD. It's a very simple process and will be mixed before you get 2 klms. Still can understand why people use petrol for blending, when it has detrimental properties for a diesel engine compared to straight diesel in a blend, as It's so illogical.

Alga,
Did you mean to write 'can' or 'can't'?
I can understand why people use ULP instead of diesel for blending:
1. It is cheaper,
2. It has lower viscosity than diesel

These 2 reasons mean that for the same $ cost you get better thinning (lower viscosity) using ULP instead of Diesel.
Obviously, if you add too much ULP, you are likely to suffer adverse effects. ( Vapour lock, Pinging, etc)
I was able to use up to 10% ULP in a blend in Summer without suffering either of the listed adverse effects, but over 10% meant that vapour lock was likely when daytime temperatures were >35°C. I never had any issues with Pinging or any other adverse issues when using up to 20% in cooler weather.

[Alga Senior Member Find all posts View Profile Close Alga]

Re: Blend before adding to tank, or in the tank

I meant "Can't" Tony and diesel is cheaper here in Tas than petrol currently. I've found even in freezing weather, 10% dino does the job here very well with no side possible effects. Plus if you don't have BD, you have to start on dino, with no other options, so using dino as a blend is economically compatible, rather than having a variety of different fuels in your system. But everyone to their own and in much warmer climates, petrol may do the job, but it does evaporate when heated compared to dino and much more volatile. Whilst adding more dino, makes no difference to performance and stability of the engine, compared to using petrol which is not designed to function in compression engines, as it is for combustion engines, two totally different concepts, environments and technology.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: Blend before adding to tank, or in the tank

Hi Alga,
Here is an interesting post from the infopop forum that will help you understand why mixing ULP/RUG with WVO does not cause the problems you are concerned with.

Posted 27/5/2005
http://www.biodieseldiscussion.com/f...etane#post1677

"I have posted this at least 4 other times, but I think it bears repeating.

Blending 20-25% RUG (ULP) with Veggie DOES NOT lower the "overall" cetane value of the fuel; it actually RAISES the overall cetane value.

Yes, RUG has a cetane value so low that it is not even on the scale.... it is on the octane scale. BUT, remember that there are 2 basic components to overall fuel cetane value:

1) Physical Ignition Delay (PID). This has to do with how long it takes for the fuel spray to mix with the air charge and find enough oxygen to autoignite. The shorter the time, the higher the cetane value for that component.
2) Chemical Ignition Delay (CID). This has to do with the Auto-ignition Temperature (AIT) of the fuel. The higher the AIT, the longer the CID and, therefore, the lower the cetane value. The reverse is also true: the lower the AIT, the shorter the CID, and, therefore, the higher the cetane value for that component.

RUG has a HIGHER AIT than WVO/SVO. RUG has a MUCH LOWER viscosity than WVO/SVO. Blending 15-25% RUG with WVO/SVO lowers the viscosity significantly, and SHORTENS the PID so much, compared to 100%, UNHEATED WVO/SVO, that the any negative CID contribution of the RUG is negligible, if not eliminated. Bottom line, blending RUG with WVO/SVO, at the ratios normally used here, RAISES THE OVERALL CETANE VALUE of the fuel blend.

Think about it. When the fuel is injected in the combustion chamber, you have free VO molecules and free RUG molecules mixing with the air and "looking" for oxygen. (I realize that RUG is a blend of Hydrocarbons, but for the sake of simplicity, here, we can safely assume a homogeneous RUG.) As soon as enough VO finds and mixes with the correct amount of oxygen, and the compression temperature reaches the AIT of the VO - BOOM - the VO will ignite, and it does indeed ignite first, and probably at multiple points througout the fuel/air mixture. THEN, because we now have a flame, with still more oxygen available, the RUG molecules will begin to ignite and help propogate the flame more quickly and efficiently throughout the combustion chamber. At this point, once the flame has started, cetane value is much less relevant, if not totally irrelevant.

I use PowerService Diesel Kleen (PSDK), which gives a 6pt cetane boost. It affects the CID of the blend, because it has a lower AIT than does the WVO. However, I DO NOT NEED to use it for startup, especially in warmer weather. I have and can successfully start up on just a blend of 75/25 or 80/20 WVO/RUG, WITHOUT the PSDK added. The main reason I add it, is because of the DETERGENT value (it helps keep the injection system clean and reduces carbon build-up) and improved combustion efficiency. However, it is a big help with startup in winter, and reduces wear and tear on my starter/batteries.

The biggest concern about running a WVO/RUG blend is finding the ratio that gives the desired results - better cold startup, improved combustion, and more power! - but without causing cylinder knock. That is purely experimental and will vary from engine to engine. But it is not a problem and, if you start with a lower ratio and work up slowly, you should be able to find the "Happy Spot" for your blend.

Oh yeah, one other thing. Blending with RUG really helps in lowering the gelpoint temp of the fuel.

I DO NOT recommend blending RUG for those that are running a heated system. Heating it can cause vapor bubbles in your fuel system.

Hope this helps!

__________________
Good Vegging and God Bless!!
24,000 veggie/blend miles and counting!

Kugel"