A lot of svo guys simply filter out the solids at the same temperature as they're going to use it at.
Or they wait for when they think the temperatures at it lowest i.e below minus,then filter.
I've never had a problem with HMPEs but have noticed some in small biodiesel samples in winter.
I've been lucky to have clear liquid feedstock oil to begin with,which would reduce HMPEs
I've read Cold water washing Biodiesel also helps.
The remark about not using reclaimed methanol for AE came from Biotom. I dont know what the reasoning is behind it but he knows what he is talking about.
John Galt, Ive been following your posts about cold filtering with interest. Could you outline your method for everyone here. We dont have to cope with the level of cold that you have in Canada but your method might allow us to use more grease in our biodiesel. Generally liquid oil is scarce here but grease is still easy to get.
Sound affair Gerard, soon as its in I'll let everyone now and we can make arrangements from there.
The two samples have now settled quite a bit and the biodiesel is beautifully clear with a sharply defined layer of crystalized bio at the bottom. The amount of sediment in the non petrol sample is quite a bit more than the treated one. However this evening it turned quite cold 3 degrees C, and what looks like a miniature snow fall appeared in both samples.
This weekend I will add a few packs of lard ( my wife will think Im heading for a heart attack) to the shopping list and make up a sample of L50 so that we can see what it looks like after a day in the fridge.
Just got word that my cold flow 402 shipment is being despatched from UK today so should be with me by weekend. Anyone else requiring a litre of same just let me know here and I will get it out to you early next week.
Anyone requiring coldflow 402 give me a call or msg me here. Shipment arrived today so 1 litre bottle which will treat 1000 lts of yellow grease processed bio diesel costs €35 including p&p to anywhere on the island of Ireland.
I've had a go at processing some yellow grease myself in my last batch. IMB, I hope you don't mind me posting in this section, I'm afraid I haven't been as scientific with my methods as you are lol... Anyway here goes. I started with 150lt which consisted of roughly 80% what we call yellow grease. This is grease that I had been setting aside for the last 8 months. I decided to process by base base with a couple of glycerol prewashes as I'm not yet set up properly for AE. It was titrating at 11 and I got the titration down to 6 by pretreating it with 80lt of glycerol over 2 40lt stages. I then processed it by base/base using 16% methanol. I had very good conversion after the first stage with just under 1ml dropout on the 30/270. I demethed and dried. It all seems to have gone reasonably straightforward, the bio looks pretty much the same as any other bio I've made, maybe ever so slightly more viscous. I've had problems with the soap removal though. I left it to settle for a few days after demeth and drying. This usually lowers my soap levels right down. However after 5 days settling the soap levels were still very high at 544 ppm, normally they would be down to between 100 and 150ppm at this stage. I put the bio through the drywash cartridge anyway but got little to no soap reduction. Yesterday evening I decided to renew my drywash medium and put the bio through again. This time though I heated the bio up to 25C, just in case it was a problem with the viscosity of the bio (I don't think this is the problem as it is passing through the cartridge well enough). It's going through the drywash cartridge all day and I'll be doing a soap test again later when I get home.
Have you added cold flow and at what stage? I can forsee problems with the drywash especially at low temperatures. In biodiesel the hmpes that are close to their cloudpoint are in the form of microscopic seed crystals. Its only when they begin to clump together that the fuel clouds. The coldflow doesnt stop them from crystalizing, it just stops them from forming big clumps which will block a filter.
The pores in the wood chips that enable ion exchange are measured in nanometres, not microns, and only a true liquid will enter these pores. This may be the reason the drywash is not working as well as it should. Raising the temperature will help, perhaps as high as 35C will be ok while not dissolving too much resin out of the wood.
Another approach might be to demeth and settle like a lot of the uk guys do. Its very slow but at least avoids the drywash problems.
I haven't added coldflow or anything else yet. I measured the soap content again yesterday when I got home after it going through a fresh drywash cartridge for the day, again at a temp of 30C, and it was 80ppm. In the picture below in the jar on the left is the feedstock yellow grease, in the middle is the finished bio that has been sitting on the windowsill outside all night, temperature this morning was 5C. On the right is a sample of the finished bio that was in the fridge for the night, temp in the fridge was 8C. It's hard to see but the jar in the middle has about an inch of precipitate on the bottom and the jar on the right(fridge sample) has about a quarter of an inch of precipitate. My conlusion from this is that this bio will be fine to use without any additives probably in a month or two's time but for use now it would benefit from the addition of something like coldflow.
Your results tally closely with mine. Biodiesel made from yellow grease will yield up to 80% usable liquid fuel at this time of the year. As the weather warms up you will get better yield. Coldflow may improve that figure, we shall see.
Over the next week you will see more wax settling out of the samples, which is why Im leaning towards the heat and settle method of removing soap. The method Im thinking of is to process as normal, demeth and dry and then transfer the bio to an uninsulated outdoor steel tank to settle for a week or more. Both soap and wax will settle out, clean bio can be siphoned off the top and the soap/wax stuff can be burned in an alaska burner to heat my workshop.
Would you do a "teaspoon test" to your yellow grease so that we can know what you are dealing with. Put a jar of your grease into the fridge overnight with a teaspoon in it. In the morning take out the spoon and describe the consistency.
Crazyhorse has been doing a batch along the same lines. He found that if he dumped his yellow grease into a 200 litre drum with a 200 watt towel rail element in it and left it overnight the grease was fully liquid by morning. A higher wattage element would burn itself out while the grease was semisolid.
I'll be setting this bio aside for a few weeks and I'll use it in warmer weather and like you say leaving anything that settles out on the bottom. I'm pleasantly surprised though at how much usable bio I've got from this stuff.
I'll do the spoon test on the grease in the fridge tonight and let you know ho it goes.
It occurs to me that one way to ensure that the biodiesel would be good for use in cold weather would be to refrigerate the settling tank. I dont know much about refrigeration , would it be possible to salvage the parts from a domestic fridge or freezer and use them to cool a 200 litre steel drum. Anybody out there with any ideas?
It gets really cold here in Canukland, so before Halloween I cut my winter biodiesel supply 50-50 with stove oil/kerosene. As the temperature drops the high melt point stuff settles to the bottom of the barrel and I pump from the clear layer through a 5µ filter into the vehicle. I'm just coming out of the 2nd winter using this method and have experienced no problems so far. When it gets really cold I add petrol to the mix. If there are any questions I can provide more details.
If you wanted to chill BD before it got cold outside it would be easy to fit a 30 gal poly barrel into an old fridge.
I left a jar of the yellow grease in the frifge overnight and did the spoon test on it today. The spoon wouldn't sit up in the grease or anything, it's definately not solid or even semi solid. I would say it's something along the lines of like thick yoghurt in consistency, that's about all I can think of to describe it.
That sounds like a bit softer than the L25 I made up. Probably L20. that would explain the good yeild. the idea of fitting a drum into an old fridge is an excellent one, however I suspect our fridges are a lot smaller than ones in Canada. I have a nice 60 litre stainless drum that would fit into a fridge if I cut a round hole in the top.
You're right, our standard fridge is 20" deep and our 30 gal HDPE barrels are 19" diameter so it's a good fit if one needs to mechanically chill for cold filtering. [a beer keg fits nicely too] Fortunately I get enough 'free' cold in my unheated fuel shed to settle the HMPEs out of the fuel mix as needed. The advantage with the HDPE barrel is that it's translucent enough that I can see the bottom of the clear layer and adjust the pump intake depth accordingly.
I made up a sample of L50 the other day and put it into the fridge to do the teaspoon test. The result is not very satisfactory. The sample has the same consistency as the L25, in fact it may even be a bit more liquid. Im not sure that this method is going to tell us anything useful about the oil/lard mixture. Has anybody any ideas about how we might test yellow grease?
what about weight or specific gravity ?
does more lard or grease mean more weight.
I know it all looks the same once its melted down but does a litre of lard weigh the same as liquid oil when cold or at room temp ?
Ive finished my test batch with L50 and the results are not good.
I made up the feedstock using 50%new rapeseed oil and 50% solid lard. It titrated at 1.5 and processed easily, good conversion. I demethed and dried it by raising the temp to 110C for about an hour, let it cool to 35C and added 1 ml of cold flow to the litre of bio.(1000ppm maximum dose)
By the next morning the whole sample was semisolid with no liquid layer on top.
The results could not be more different from the results of the L25 batch ( same oil, same lard) that one is now beautifully clear liquid bio with a layer of crystallized semi solid at the bottom ( about 15% of the total volume.
The theory Im developing from this is that there is a maximum level of lard that can be mixed into oil to get a successful usable result and it would seem to be about L30.
Our problem is how do we measure and recognize L30? My teaspoon test does not seem to be telling us anything useful.
I dont think oil and lard will have different Specific Gravities Trigger. Im wondering would the viscosity be different at a given temperature. Another possibility would be to warm up a sample and then observe the cloud point as it cools.
I did set aside some of the L50 bio that had not been treated with Coldflow and its is even thicker that the treated sample, in fact its almost solid.
Here is what the batches look like. L25 on the left and L50 on the right.
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