The resin in woodchips is nearly all flushed out with the first batch of biodiesel (at least using gravity as I do). The amount of resin is quite substantial.
I've said previously that the resin can be washed out of the fuel with a water wash. However, I've discovered that given time the resin will drop out of the biodiesel of its own accord, usually within a day or two at the most. I think natural settling is preferable to water washing this first batch, and I will now adopt it.
I also reported that resin is soluble in RUG, which it is. However, for some reason the petrol doesnt extract the resin from the fuel, which still shows signs of fall out. I've had no trouble running on fuel which hasnt had the resin removed, but now that I've seen it drop out I'm wondering why it hasnt blocked my filters.
Its no big deal having to allow the first batch done with new woodchips settle for a day or so. Subsequent batches do not require this, and the wood lasts a longgggg time.
RolfQuo's set up is 4 drums of chips in series which are esentially gravity fed for the most part (only 1PSi to get it all started)and at last count over 50,000 litres has gone through them and hasn't shown signs of dying out yet. I'm happy, I got one of their drums all prepped and ready to go :-)
Luc, how much woodchips do they put each drum?
Choc-a-block and hand tapped down. The stainless filter is a cut out piece of pipe screwed into a short nipple at the bottom and then the filter is covered with a split longways piece of drain piep to stop compaction and clogging of the filter. The stainless is 70 mesh. I have some pics on my dry wash page (page 2), but only of the filter and drum, not the chips.
I've only run about 100L through my new set up so far but I like it ... alot. The drum holds onto 100Lts which is rotated as new biodiesel enters, which to me is no problem as I am now producing all year.
Jehu I have tried to was a sample of the filst pass of bio through the chips. What I found is that the water turns into a thick cream almost instantly and that it has to be very very gentle. Ok, I have used sftwood chips to start with, so resin would be exccessive. Your observation that the resin drops out makes me think to use some bio from the first batch to "flush" the chips and then store that bio seperately for a few days.
This may be a dumb Q or I am missing a piont with all my reading...Is there a link between washing the chips with methanol and the removal of resin, or is the methanol wash only to "charge" the chips and the resin will be flushed out with the first pass of bio anyway?
Land Cruiser 4.2tdi, Figo 1.4tdci,
Thanks for that Luc - thats interesting.
Hannes, good idea - why couldnt I think of that! I have heard that the resin can be removed by flushing with methanol, altho I have only other people's word for it. But, you're right, the resin will be flushed out with clean biodiesel from a previous lot, which as you say can be stored and left to settle afterwards.
This has two advantages over flushing with methanol: first, our own biodiesel is cheaper than methanol, and second, we wont have to bother with having to dry methanol from the shavings afterwards.
6 of one 1/2 doz of the other. If you flush with methanol you can still use that in a follow up batch. To "dry" the chips run biodiesel through it and then rebatch the bio through the distiller.
Simple is best though, and unless you're set up to do it the long way then K.I.S.S.