Unconfigured Ad Widget

Collapse

Announcement

Collapse
No announcement yet.

Prewash and Bubble

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

  • Prewash and Bubble

    Just wanted to know if anyone has had similar experiences.

    I'm making 130lt batches of bio. I react for an hour at approx 60 deg C, use 20% meth with NaOH. Oil titrates at 0.5.

    I add 5% water to prewash and mix for approx 15 mins leave a gap and then another 15mins mix for good luck. I now have chicken soup. Let it stand for 48 hrs then drain off glycerine waste. Place remaining chicken soup bio in bubble tank. I bubble for one day and it is crystal clear and passed 27/3 test.

    Cheers Peter<><

  • #2
    Re: Prewash and Bubble

    ...but does it still have soap and methanol in it?

    Comment


    • #3
      Re: Prewash and Bubble

      ...thats the sort of thing I was trying to find out. Can it still have soap and methanol if it has cleared up and passes the 27/3 test?

      Peter<><

      Comment


      • #4
        Re: Prewash and Bubble

        I add 5% water to prewash and mix for approx 15 mins leave a gap and then another 15mins mix for good luck. I now have chicken soup.
        Hi Peter, can you expand on your description of 'chicken soup'? It is my understanding that the guys over at Infopop use this term when they have created an emulsion. This doesn't appear to be the situation in your case if it dries up in 24 hours. Wet bio is usually the colour and clarity of orange juice.

        Extended periods of bubble drying should remove nearly all of the methanol allowing any residual glycerine and most of the soap & other contaminants to drop out, producing perfectly acceptable fuel for most vehicles. But in my experience water washed bio is a superior product (but it uses a bit more time and a lot of water to get it). Bubble dried bio turns my disposable filters black in about a month. No big deal, I can live with changing a $3 filter every few weeks.

        Comment


        • #5
          Re: Prewash and Bubble

          Originally posted by PeterAC View Post
          I add 5% water to prewash and mix for approx 15 mins leave a gap and then another 15mins mix for good luck.
          Peter, the 5% pre-wash should remove about 50% of the soap and some of the residual methanol to the glycerol layer. But there will still be soap and methonal in the bio layer.

          Let it stand for 48 hrs then drain off glycerine waste. Place remaining chicken soup bio in bubble tank. I bubble for one day and it is crystal clear and passed 27/3 test.
          As I understand it..
          Passing the 27/3 test indicates that there is no discernible glycerine in the BD but doesn't reveal anything about the soap or methanol content of the BD.

          Passing a Crystal Clear clear test indicates that there is no suspended water left in the BD but also doesn't reveal anything about the soap or methanol content of the BD.

          I would think that bubble drying 100+litres for one day may not be long enough to get rid of the methanol that 'holds' the soap. You did not say if any soap was removed from the top or bottom of the mix during bubble drying.

          I suggest you take a sample of your bubble dried, crystal clear bio that passed the 27/3 test and put it in a jar with 30% water. Shake vigerously for 30 seconds and let it stand until it separates. If the water is cyrstal clear, your bio is good quality and has no soap in it. If the water is not crystal clear, there is still soap present.

          Comment


          • #6
            Re: Prewash and Bubble

            Originally posted by gwalker View Post

            As I understand it..
            Passing the 27/3 test indicates that there is no discernible glycerine in the BD but doesn't reveal anything about the soap or methanol content of the BD.
            It was my understanding that the 27/3 test detected any unconverted oil as oil isn't soluble in methanol.
            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


            • #7
              Re: Prewash and Bubble

              Sorry about the delay in reply.

              Chicken soup is milky coloured not an orange juice colour if that helps

              I'll try the 30% water mix up and reply.

              There was glycerine at bottom and no foaming anything floating on top but I don't know what to look for to identify soap if it is not the foamy stuff on top clumped together.

              Thanks for this info gentleman!

              Cheers Peter<><

              Comment


              • #8
                Re: Prewash and Bubble

                George,

                I tried the soap test. After about 2 hours I went back to look at the settling and yes there was cloudy water ie. soap. Thanks for this test.

                The following day I noticed the cloudy eater getting clearer and again the following morning even clearer. There were only two layers visibly present, the bio and the water. I haven't looked at it today, day 3.

                What does the ever clearing water mean?

                Cheers Peter<><

                Comment


                • #9
                  Re: Prewash and Bubble

                  Originally posted by PeterAC View Post
                  George,

                  I tried the soap test. After about 2 hours I went back to look at the settling and yes there was cloudy water ie. soap. Thanks for this test.

                  The following day I noticed the cloudy eater getting clearer and again the following morning even clearer. There were only two layers visibly present, the bio and the water. I haven't looked at it today, day 3.

                  What does the ever clearing water mean?

                  Cheers Peter<><
                  Peter, The short answer is I don't know. Was there any sediment on the bottom or a surface layer between the water and bio?
                  George<><

                  Comment


                  • #10
                    Re: Prewash and Bubble

                    No sediment, just got clearer each day. If I tilted the bottle there was an ever so slight 'stuff' attached to the wall of bottle, soap??? This was in between the water and bio.

                    Peter<><

                    Comment


                    • #11
                      Re: Prewash and Bubble

                      Hi Peter,

                      First of all, the 27/3 test as I understand it is designed to detect the conversion rate of the triglycerides into methyl-esters. If there are any remaining tri, di or mono-glycerides left in your biodiesel then you have an under-converted sample. Thus, the fact that it passed the 27/3 test implies at least a good conversion...but nothing about the remaining levels of CH3OH (methanol) or NaOH.

                      A good test as suggested is the wash test, which by most standards is 50% water to 50% bio. Shake for a few seconds (doesn't need to be 30) and watch how quickly the layers separate (leave for about half an hour maximum). Unfortunately it is not really a black and white test. Your water can be cloudy, even with a good quality low soap fuel. Generally the wash test is only to determine if you have really underprocessed fuel. The bigger the soap layer generally the more water soluble contaminants left in the biodiesel, i.e. soaps, mono and di-glycerides.

                      If you are really concerned abou the soap content and can't afford any astm testing then I would recommend you do the simple soap test at home. See: Testing for Soap in Unwashed Biodiesel and Glycerol - Collaborative Biodiesel Tutorial. You just have to find some bromophenol blue.

                      In terms of methanol an easy test is the weighing/bubbling test. NOTE: DO THIS TEST IN A HIGHLY VENTILATED ENVIRONMENT. Also be aware that venting meth into the atmosphere is not good for the environment. In my setup I recapture the methanol using a condensor. Take a small sample, say 500ml, and measure the weight including the beaker or jar it is in. Heat this sample to 90 deg C and observe for bubbling. The more methanol in the biodiesel solution the lower the boiling temperature will be of the methanol (i.e. much closer to 64 deg C). However as more of the methanol is bubbled off then the in-solution boiling temperature of the meth will increase. Unfortunately what you are boiling off is not 100% meth, it will contain a higher percentage of water the closer you get to 100 deg C. But hopefully you have removed the majority of water from your fuel during bubble washing, so this won't be a problem. Once the bubbling has stopped, take off the heat source and let cool then weigh again. The difference in weights is the amount of methanol left in solution.

                      On another note, if you want to store your fuel for more than a couple of months then I recommend you consider stir water washing or one of the many waterless washing methods instead of bubble washing. Bubble washing oxidizes (adds oxygen) the fuel, which means very little storage time before the fuel will cause damage to your engine.

                      Hope this helps.

                      Cheers
                      Alex

                      Comment


                      • #12
                        Re: Prewash and Bubble

                        Originally posted by UNSWSolar View Post
                        Hi Peter,

                        Bubble washing oxidizes (adds oxygen) the fuel, which means very little storage time before the fuel will cause damage to your engine.
                        Hi Alex,

                        Can you please expand upon biodiesel going bad? On this forum, we've had lots of questions about the shelf life of bio, and some mention of oxidization, but, as far as I'm aware, no clear-cut test for when the bio has gone bad.

                        I know there's at least one person who has kept a sample of biodiesel for something like a year, to try to see how long it lasts.

                        Also, what kind of damage would be done to the engine?

                        Thanks,

                        Justin

                        Comment


                        • #13
                          Re: Prewash and Bubble

                          Originally posted by UNSWSolar View Post
                          ... Bubble washing oxidizes (adds oxygen) the fuel, which means very little storage time before the fuel will cause damage to your engine. Alex
                          Alex,
                          How long is very little and what damage is caused?
                          George

                          Comment


                          • #14
                            Re: Prewash and Bubble

                            Hi guys, sorry for the delayed reply. Been busy this week.

                            In terms of engine damage:
                            According to Mittelback and Gangl: "hydroperoxides produced during the initial stages of oxidation decay may polymerise with free radicals to form gums that can plug your fuel filter and injection system." Basically in combustion conditions fuel that has begun oxidizing can polymerise (i.e. turn to plastic) on fuel injectors...not the best thing. As the fuel is oxidized the viscosity also gradually increases, which can place it above the recommended specs for diesel fuels. No time limit on that one unfortunately.

                            Further oxidation forms short chain carboxylic acids, linked with injection system corrosion.

                            The extent to which the bio will polymerise is directly linked to the iodine value of the incoming feedstock. If you are making your bio from coconut oil the fuel will polymerise more slowly. Rapeseed also has a low iodine number. WVO can be a mix of many different oils so it is hard to tell what the iodine number might be unless you test it.

                            Unfortunately I personally have not conducted any tests and I have not really found much out there in relation to bubblewashing apart from examining the oxidative stability values of a few tested batches of bio. The ones that did not pass used bubble washing. Best advice is that if you bubble wash, use the fuel quickly. There are anti-oxidants you can add to the fuel if you are worried about oxidative stability with bubblewashing, however I am sure they will be hard to find.

                            Anyway, I hope that helps a little. Still not black and white though. I just figured better to avoid yet another problem.

                            Cheers
                            Alex

                            Comment


                            • #15
                              Re: Prewash and Bubble

                              Peter to my knowledge the cloudy look of the water is methanol if there was no middle layer of soap forming overnight. Aerated water from shaking also appears white in water. You can heat bio to >80degrees to remove methanol and just observe soap.

                              Comment

                              Working...
                              X