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Thread: Using a digital ph metre instead of titration?

  1. #1
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    Jan 2010
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    Using a digital ph metre instead of titration?

    I have searched for this and have found only a couple of obscure examples of a digital ph metre being used to test acidity as opposed to doing a titration.

    Does anyone here use a metre? Is it as acurate as titration?

    I am scratching some gear together to do my first batch and I already have a metre so not getting a titration kit together would save some $$.

    It seems the hardest thing out of everything when it comes to making bd is getting a source of wco. I have been to about 10 fast food/restaurants but it seems they are happy it already gets picked up by waste management companies. I have another 100 places to check before I start getting disappointed

    Sorry if this has been answered already.

  2. #2
    Join Date
    Sep 2005
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    WA
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    Re: Using a digital ph metre instead of titration?

    Apart from the cost of a good pH meter, there is the cost of ensuring it is calibrated and then the cost of buying buffer solution to prevent contamination of the electrode(s).
    You will still need to do a titration, but instead of using an indicator, you use the pH meter to determine the end point of the titration.

    you can't use a pH meter directly in oil and expect any meaningful results. Oil does not have a pH, it is a measure of hydrogen ions in an ionic (water, alcohol, etc) solution. Oil is not an ionic solution.

    Titration requires you to dissolve some oil in an alcohol solution and then add a weak solution of caustic to the solution of oil and alcohol.
    An indicator, phenolphthalein or Curcurmin (Turmeric) is used to determine the point at which the fatty acids in the oil are neutralised. These indicators were chosen for their colour change point which ~ pH8, slightly alkaline.

    So spend $50 -$1500 for a pH meter and ongoing costs to use it, or go to the supermarket and buy some Turmeric spice. Use the broad end of a toothpick to add a tiny amount of Turmeric to the solution to get a vivid change from Fluoro Yellow to Beetroot Red at the end point.

    Not hard and a visual indication of when to stop adding the titration solution.

    I hope this helps,

    Tony
    ps, it has been answered before but I am too lazy to search for it for you.
    Last edited by Tony From West Oz; 25th January 2010 at 11:39 PM.
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  3. #3
    Join Date
    Aug 2006
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    Kojounp W.A.
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    Re: Using a digital ph metre instead of titration?

    Hi Lickapop and welcome to the wonderful challenge of making bio diesel.
    May I suggest that you offer 10 cents per liter to the restrant or at least match the price that the fat companies are paying and perhaps a bit more.

    This will give you a slight edge in ensuring that they keep water and other crud out of your drum. If you are prepared to pay a bit more for quality then supply will not be an issue and you can improve the quality of your feed stock and make less work for your self when making bio.

    Good luck and welcome to the forum.

    Cheers
    Sandman.
    Last edited by Sandman; 26th January 2010 at 12:02 AM. Reason: typo's

  4. #4
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    Re: Using a digital ph metre instead of titration?

    hey thanks for the info. So much to learn

    Well I have a few more places to ask for oil but it could very well come down to paying a bit for it. It seems that the places I have visited already are on the defensive when it comes to their oil. They think I am from the epa doing a raid or they make their own diesel and and chase me out of the shop with a broom ( bit of an exaggeration but if I hung around another minute they would )

    My partner manages a tech college and she uses a guy who comes in and pumps out the oil and replaces it weekly for $68. I am not sure how many litres but even she wont give up the oil. She was saying that other companies have offered to do it for half that cost.

    I may sound a bit too keen but do these waste oil companies give up their oil cheap or dont even go there? (edit- actually stuff em... they are the enemy. I would rather pay a source)
    Last edited by lickapop; 26th January 2010 at 08:34 AM. Reason: lame question

  5. #5
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    Brisbane (North Side)
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    Re: Using a digital ph metre instead of titration?

    There is another option - dare I say it.......

    Don't ask.

    I have been magically removing the waste oil from some of the local businesses here for over 4 years with no problems at all. If you don't make a mess, it wont be a problem. Of course I only go to places where I know the owner does not get paid for removal, so it doesn't hurt the shop keeper at all. I know most of the chefs now and they all sing out g'day when I am pumping oil at 5.00 am Sunday morning in my high vis vest.

    I share my run out between several places and go about once a month and collect 800 to 1000 litres in my trailer which keeps me going without cutting across the boughs of the oil collectors. things may probably be a different here in brisvegas, but it works, is hassle free and is FREE.

    I am sure some people will have a hard time with this, its just a matter of needing it more than the oil companies. A lot of places will just say "no" as it is easier than going through the hassle of changing systems to someone they don't know or trust, and the oil removal makes up such a small part of their business that is not worth changing.

    If you appear legitimate, and am willing to get up before the sun, you can enjoy a lot of easy to obtain oil, without having to appear cap in hand and say "please sir?"

  6. #6
    Join Date
    Jan 2010
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    Townsville
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    Re: Using a digital ph metre instead of titration?

    dont ask ? lol..yeah well if thats the case if there is anyone from Townsville who makes BD, it may be a good time to stake your claim here

    I heard touching a mans wco source is like touching a mans woman.......you just dont do it

  7. #7
    Join Date
    Dec 2005
    Location
    Canberra
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    Re: Using a digital ph metre instead of titration?

    I never bothered with the big guy's chase the smaller resturants i.e. the 10 litre a week places and pickup forthnightly, realistically you are only going to need approx 5 - 20litre pickups a month, in doing so I got a couple resturants that supply me minimum 40litres a fortnight. I have a float of 1200litres and just gave 300 litres away to a friend. I feel that if you have small pickups and you loss one it isn't that much of a drain on your supplies but if you had 1 or 2 big pickups and you lose one it could take you weeks to recover....
    Suppose bottom line is just keep looking
    BTW I once spoke to the big collectors and they by law here have to collect all wvo if requested and going around to collect 20litres at the little places bugs them, he basically encouraged me to pickup the little places for him as it wasn't worth much to them.... also the small resturants would call the collector and sometimes they would end up with a couple hundred litres lying around just waiting for them to finally come to collect it. So they love my service they know that on this day I'll be there with fresh containers and once a year at Xmas they get a bottle of Red...
    HDJ80 (aka Kiwipete)
    Canberra

  8. #8
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    Sep 2009
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    Brisbane (North Side)
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    Re: Using a digital ph metre instead of titration?

    The last few lines gave it away for you dave, when it comes down to it your chicken too!!!

    Yep, for a while there they tried putting a grill on the drum to stop blokes like me from bailing it, but I just put together a pump with an inlet pipe smaller than the holes in the grill. Quite simple really. Round 1 to me...

    They then tried locks, but this didnt work as the lock was a complete pain to the shop keeper, as they could never find the key at 9pm at night with 40 litres of hot oil waiting to go in the drum. Round 2 to me....

    Eventually they gave up and realised that the small amount I take is not worth the extra cost of policing or retrofitting all of the drums.

    Round 3 to me.

    It is now developed into a rather symbiotic relationship (maybe parasitic relationship??) between us that has gone on happily for years.

    May we be forever joined in oily happiness......

    But I reiterate, I never spill a drop, am quiet, get on well with all the staff, and in a couple of places it is obvious that the oil is collected by little blokes, so I leave that alone.

    Its all good really.....

  9. #9
    Join Date
    Feb 2010
    Location
    South East Qld Australia
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    67

    Re: Using a digital ph metre instead of titration?

    My thoughts on turmeric are to call the base 4 instead of 3.5 as it seems to turn red a little early. As for oil pick up I have two food out lets that thank me for taking it, rock up on a weekly basis with real clean drums to leave and take oil. Not big amounts but constant other places I get with the chef saying giday while I bale and never any spilt. Other places have stopped because they put in the filter system which I think must be unhealthy as the oil is changed maybe once a year. Us oilers find out the best and cleanest places to eat real quick, we don't eat at the canola oil users or the place where they put tea bags in the oil to change the flavor of the fish.

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