Appears that we're not the only ones to suffer HMPEs

[Julian]

Just listened to "You and yours" on radio 4, talking about diesel cars suddenly loosing power or going into limp mode.

An RAC "fuel expert" said he knew of over 600 cases and they were investigating the problem.  He said normal waxing in dino diesel, occurs and then melts when temperatures rise.  But with this new phenomenon, it was strange in that the waxing, once formed, didn't remelt when the weather warmed up ... all sounds very familiar!

They said a new test (not currently standard) would be introduced to check for cold weather performance (sound like a cold filter plug test) and that he suspected it may have something to do with the biodiesel that now had to be added to dino diesel.

[Tony]

I wonder if this is what he was talking about?

http://www.biofuels-news.com/industry_news.php?item_id=7384

‘During the cold soak the sample is chilled to 5°c and held at this temperature for 16 hours. After the cold soak the filter blocking tendency is determined using IP 387 Procedure B.’

The test process requires payment to read about but presumably some form of filter specification and flow pressure/time measurement?

http://www.energypublishing.org/publication/ip-standard-test-methods/ip-387-determination-of-filter-blocking-tendency

The ASTM standard for doing this, D7501, cold soaks the fuel and then measures the time to filter, under vacuum, a volume of the sample.

[julianf]

Given that theres a commercial value for solid oils (ie theyre in demand for somthing) it would not surprise me if some find their way into forcourt pumps.

I know that powergen can also use solid fats, but, still, id think some go for road fuel.

[Jamesrl]

Having seen some of the so called Biodiesel thats sent for blending I'm surprised this hasn't been a problem before now.

HMPEs and waxing is the reason I decant into 25ltr containers and leave outside and re filter before use.

[Manfred]

Being a new boy to this Bio malarkey, can I use the HMPEs when they melt back or do they need re processing ?
 The reason I ask is I've just found some in the bottom of my settling tank. Low temp's they there but at room temp over night  they disappear.

[Jamesrl]

HMPEs never return to a liquid state once formed, waxing does.

You'll soon get to know the difference between'm.

Having said that I believe Tony adds his HMPEs to a batch for reprocessing.

[Julian]

Jim ... HMPEs do return to a liquid state, but at a higher temperature than the one they formed at.

[nigelb]

Have I ever mentioned that I don't get HMPE's

[julesandtash]

I think I vaguely remember you saying something about that a long time ago Nige 

[Tony]

Yes if I get any I reprocess mine in the next batch, I'm pretty sure they're monoglycerides rather than waxing so a tiny touch more Meth and catalyst turns them into very much useable biodiesel.

[Jamesrl]

Jim ... HMPEs do return to a liquid state, but at a higher temperature than the one they formed at.

Yes I know you can liquefy them but not buy ambient temperatures in this country or by leaving them in your bio until summer comes.

[Manfred]

Thanks chaps. Looks like I got waxing then.

[Twenty4Seven]

Jim ... HMPEs do return to a liquid state, but at a higher temperature than the one they formed at.

Yes I know you can liquefy them but not buy ambient temperatures in this country or by leaving them in your bio until summer comes.

What I do is save the HMPEs until summer then add them to the settling tank prior to dumping in a fresh batch of bio from the processor. The bio is at 90*C and the HMPEs definitely do dissolve. They do not drop out again at ambient summer temperatures.

Nick

[1958steveflying]

Jim ... HMPEs do return to a liquid state, but at a higher temperature than the one they formed at.

Yes I know you can liquefy them but not buy ambient temperatures in this country or by leaving them in your bio until summer comes.

What I do is save the HMPEs until summer then add them to the settling tank prior to dumping in a fresh batch of bio from the processor. The bio is at 90*C and the HMPEs definitely do dissolve. They do not drop out again at ambient summer temperatures.

Nick

That's a good process Nick.