Unconfigured Ad Widget

Collapse

Announcement

Collapse
No announcement yet.

water washing

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • water washing

    Hi all,

    I've been reading about water washing and was interested to see what you all have been doing. Could you please make comments about:
    • what water to BD ration you have been using
    • how log you agitate and settle for
    • do you use a paint stirrer, water pump or use an air bubble system
    • do you wash more than once
    • what do you do with the water


    Thanks for your time and comments.

    Joe
    Joe Morgan
    Brisbane Biodiesel Site Admin
    http://www.brisbanebiodiesel.com

    Searching tips using Google - SVO Dual tank systems
    SVO, Common Rail and Direct Injection - Vehicles converted to Used Cooking Oil

  • #2
    Re: water washing

    I have been bubble washing.
    40 litres water at each cycle.
    3 hrs
    3 hrs
    12 hrs
    and even another 12 for good measure.
    I over wash but what the heck.
    I am about to setup a mist system for the first couple of washes.
    First 2 washes should be gental especially the second as that is where you will have problem's with emulsion if you are going to have emulsion issue's.
    HDJ80 (aka Kiwipete)
    Canberra

    Comment


    • #3
      Re: water washing

      HDJ80, do you do a 5% water mix in the glycerin before draining it off? The addition of the 5% water to the glycerin will remove about 3/4 of the soap from the biodiesel (it will also release any biodiesel that is trapped in the glycerin - as much at 4% extra biodiesel may be available in the glycerin).

      It doesn't take much residual glycerin in the biodiesel to cause emulsion problems. Any little ridges in the plumbing can catch a bit and they all add up. This is one area of processor design that everyone should pay a great deal of attention to.

      Comment


      • #4
        Re: water washing

        No I don't add any water to the processed bio/glycerol I just want to keep water well away from that part of the reaction.
        Yes you are right that you have to get next to know glycerol into the wash and I am as careful as I can be to prevent that. But as you said it is there somewhere in the plumbing.
        If you take a look at the pics of my processor you may see that there are taps every bloody where. Well there is a good reason and it is so to separate the reaction from the plumbing as much as possible.
        So after mixing I shut off the tap closest to the base of the reactor and from the drain tap (lowest point of the plumbing) I drain the plumbing into a PET bottle. I get approx 500ml's and I get to watch the reaction in the PET bottle. BTW That drain tap stay's open to get as much out as possible. When I drain off the Glycerol (starting half to an hour after the mixing has stopped) I drain it from the tap on the far right i.e. closest to the base of the reactor.
        After settling has completed 8-24hrs later (at least 8 hrs) I shut all drain taps and turn on off taps till I get the path to the washtank. But the first litre or so is set aside as it is the bit that likely has residual glycerol in it. I is reprocessed in the next batch or set aside and the top Bio moved to the wash tank at anytime later...
        That's how I get around that with my processor.
        Mind you what you have said is news to me and worth investigating
        HDJ80 (aka Kiwipete)
        Canberra

        Comment


        • #5
          Re: water washing

          The 5% pre-wash is done after the reaction takes place. Normally with the processor running at 50C+ the reaction is complete in an hour (actually around 45 minutes). Then the water is added - it is 5% of the volume of oil that is being esterfied. So if you had 40 litres of oil, the additional water would be 2 litres. You then run the mix for a futher 15 minutes and then shut off and let it settle.

          Here is a link from a fellow that only uses the pre-wash as his total wash method. Such a method saves on disposal of wash water (not to mention time and effort). Maybe it will work for you.

          http://biodiesel.infopop.cc/groupee/...411#4421079411

          You can use the FIND function in the infopop forum to locate other posts regarding the pre-wash. Just type in pre-wash.

          http://biodiesel.infopop.cc/6/ubb.x?a=cfrm&s=447609751
          Terry Syd
          Senior Member
          Last edited by Terry Syd; 10 January 2006, 07:15 PM.

          Comment


          • #6
            Re: water washing

            Hi Hdj80, I'd just like to reinforce what Terry Syd said, you really should give the 5% water pre wash method a go. It makes the final washing sooo much easier. It takes a bit of courage the first time you add water to the reactor, but try it on a small batch first. Try it in your 500ml samples in the PET bottle for the next batch. Do one with water and one without, just to prove it to yourself. It may even keep your NaOH glycerine liquid.
            Following the water pre-wash, the settled (wet) Bio comes out the reactor like orange juice. This is normal. Just set up your mist washer, as you said, for the first 2 washes and you'll find you need a lot less water and there'll be a lot less white floaty bits at the interface.
            I follow up the 2 mistings with a couple of bubble washes ~20L water per 100L BD then drain the water, bubble & fan dry at room ambient temp for 24hrs.

            Comment


            • #7
              Re: water washing

              Courage is the word....
              I am really quite nervous about giving that ago, I was thinking the otherday why I was so put off about trying that, I have given most other things ago in the past. Well for the past 2 years I have been reading "Keep water out of the process" "dewater" etc etc and what you are asking me to do is add water to the processor. However you have not asked me to add water to the process but after the process has completed, so I can nearly live with that. Where I am still nervous is that the feed stock I have been getting has next to no water in it and my processor is dry of any water. Just the way I like it.
              However I will do what you suggested in doing some test batches outside the processor and "see for myself". Looking forward to that as anything to save water.
              I did do mist washing for the first time this past weekend and I was very surprised. I did 2 washes of approx 50litres water each, which I have kept the water so the Methanol would evaporate before it goes on the lawn (BTW how long should that take in a open top 44). and completed one 12hr bubble wash using 40litres water I will do the same tonight.
              Very quick and very effective but alot of water used. Then again if I can get that methanol out of it the lawn will be happy.
              HDJ80 (aka Kiwipete)
              Canberra

              Comment


              • #8
                Re: water washing

                Hi Hdj80, you certainly are very generous with your quantities of water in the wash.
                I think that that the methanol would take a very long time to evaporate from a vat of water. But the concentration would be very low, maybe like spilling beer or wine on the lawn. However, I think if you poured the water on the same patch of grass for a long time, the alkalinity may build up and kill the grass. Do you neutralise the water with acid?

                I've attached some photos of a couple of batches I made a while ago to test the efficacy of the pre wash method. The photos show two identical samples of biodiesel, the bottle on the right used the 5% water pre wash. Unfortunately, the pictures do not do it justice, but I think you can see that the water from the prewashed BD is significantly clearer. But most importantly there is a lot less of the white fuffy stuff at the cuff or interface. This does not show up on these pictures at all. By the way, I make my BD with KOH and my oil source is pretty good, usually titrates at between 1-2ml.

                Good luck with your test batches, I'm sure you'll never look back.

                Comment


                • #9
                  Re: water washing

                  Boy that second wash on the right looks amazing. And thats after a 5% water/glycerin wash right. You would barely need a 3rd wash after that.

                  Joe
                  Joe Morgan
                  Brisbane Biodiesel Site Admin
                  http://www.brisbanebiodiesel.com

                  Searching tips using Google - SVO Dual tank systems
                  SVO, Common Rail and Direct Injection - Vehicles converted to Used Cooking Oil

                  Comment


                  • #10
                    Re: water washing

                    Joe, I expect the effect of the 5% water wash is even more efficient than the pictures indicate. Note that the biodiesel still appears cloudy. This is likely because all the water/soap has not settled out of the biodiesel.

                    It is the alcohol in the biodiesel which has the most effect on keeping the glycerin in solution. Alcohol is very miscable with water. After the first 5% pre-wash, most, if not all the alcohol has been moved to the glycerin.

                    What is remaining in the biodiesel is a mixture of soap and water. It will eventually drop out. However, if you do another wash, then that wash will dilute the existing soap and water and most of it will precipitate out quite quickly - however the biodiesel will still be a bit cloudy with tiny water droplets in the biodiesel.

                    Some people just do the 5% water pre-wash and then let the biodiesel settle. For many applications this is enough to prevent filter clogging problems.

                    I know of no emperical testing that indicates that a bit of soap in the biodiesel is a problem to engine running or long-life. The major problem with soap in the biodiesel is that it can clog the fuel filter. If a 5% pre-wash eliminates the clogging problem on your vehicle, then further washing appears to have no other purpose for your vehicle than feeling the comfort afforded by the old saying of "better safe than sorry".

                    You can see from the pictures of geewizztoo that the first pre-wash did a good job of eliminating the glycerin/soap from the biodiesel. If he had allowed the biodiesel to totally settle and then drained off what precipitated out before he did the first water wash (that is, let the biodiesel clear), I would expect that the first water wash would have been even more impressive.

                    Perhaps he might give that a go and post the results? Geewizztoo?

                    Comment


                    • #11
                      Re: water washing

                      I'm just wondering if the increased yeild of the "5% water/glycerine wash" could be attributed to remixing the methoxide mix through out the unconverted bd. Similar to the "80/20%" methods of rereacting biodiesel.

                      my 2 cents worth
                      Joe Morgan
                      Brisbane Biodiesel Site Admin
                      http://www.brisbanebiodiesel.com

                      Searching tips using Google - SVO Dual tank systems
                      SVO, Common Rail and Direct Injection - Vehicles converted to Used Cooking Oil

                      Comment


                      • #12
                        Re: water washing

                        Joe, over on the Infopop forum one of the members, "Neutral", is an industrial chemist. He did extensive experiments to determine the minimum amount of water that you could add to release the bound up biodiesel. It came out at 5%. You can add more, indeed the University of Idaho initally recommended a 15% addition, however you only need to use 5% to get the results.

                        You can add more, but do not use more than 15% or you may end up with an emulsion when you remix it.

                        5% also cuts down on the amount of liquid glycerin you have to get rid of. If you add more, then you have that much more liquid to dispose of.

                        Comment


                        • #13
                          Re: water washing

                          I wonder if you do a pre wash followed by a waterless wash with talc what the out come would be like I have been experiementing with talc and found it to work ok
                          started on bio now on blends next a svo conversion 1986 toyota 4runner

                          Comment


                          • #14
                            Re: water washing

                            Originally posted by Terry Syd
                            Joe, over on the Infopop forum one of the members, "Neutral", is an industrial chemist. He did extensive experiments to determine the minimum amount of water that you could add to release the bound up biodiesel. It came out at 5%. You can add more, indeed the University of Idaho initally recommended a 15% addition, however you only need to use 5% to get the results.

                            You can add more, but do not use more than 15% or you may end up with an emulsion when you remix it.

                            5% also cuts down on the amount of liquid glycerin you have to get rid of. If you add more, then you have that much more liquid to dispose of.

                            Thanks Terry, this BD stuff never ceases to amaze me. I wonder sort of reactor he was using? Appleseed, mechanical reactor?? I have read a few of his posts but have never come across that.

                            Joe
                            Joe Morgan
                            Brisbane Biodiesel Site Admin
                            http://www.brisbanebiodiesel.com

                            Searching tips using Google - SVO Dual tank systems
                            SVO, Common Rail and Direct Injection - Vehicles converted to Used Cooking Oil

                            Comment


                            • #15
                              Re: water washing

                              Joe, here's another trick regarding a pre-wash. While I was working on potential biodiesel project in New Guinea using coconut oil, I worked up a very quick and easy wash system.

                              The coconut oil I was using was low FFA, so if anybody wants to try this they may have to do some experimenting. Also, I was developing the system using a stociometric amount of methanol for the reaction (mentanol would have to be imported to PNG, so costs were a big consideration).

                              I found that if I dropped the pre-wash back to 1% with a caustic soda (NaOH) catalyst or 2% water pre-wash with a potassium hyroxide (KOH) catalyst, that when the glycerin dropped out - the biodiesel was crystal clear. In other words, you didn't need to dry it!

                              If all you have access to is high FFA oil, then you will need the full 5% water pre-wash to drop out the bound biodiesel, however, if a person has low FFA oil, then this pre-wash method might save a lot of time and effort.

                              Comment

                              Working...
                              X