i love this thread.. when i first started visiting this forum, and researching BD, the time, mess, and chemistry of it all was a little bit intimidating, and needed patience I'm not sure I have. Every time i come back, there's some new development that seems to make making bd cheaper, simpler, easier, and less messy.

If you were running the distributor at 6000 rpm then this would, assuming a four cylinder unit was being used, give you 24000 pulses per minute (four pulses per rev) that is 400 per second. Even at half of this it would probably still give you a result. When I get chance I will dig out an old coil and run some tests.

This is an interesting thread you have going. Keep up the good work.
regards
dva

The duration of the spark is only around 0.2mS

And if the engine is a 4 stroke, you only get a pulse on each second cycle.

So the pulse is present only 0.2/1000 x 200 = 4% of the time at 6000 RPM

So, has around 1/25 th of the effect of the mean pulse voltage.

I'm splitting hairs here - a spark coil should still be useful, I'm sure.

But be careful - they do give one heck of a jolt!

Any progress on the inline module Graham?

Bump.

You still busy at work Graham?

Hi Ant

I've been away in France doing an exhibition for the past week, just got back and have a few more ahead, so I'm far behind on my biodiesel work. Roll on the Xmas break!

The inline purifier works well on small scale, I found a simple, effective way to collect the glycerol or water or whatever other dropout material you want to get rid of.

The collector tank has a capacity less than the expected total contaminant volume. As you detect the contaminant rising to a preset level, you drain a small defined amount out of the lower container, to minimise the amount of biodiesel in there.

The balance tube is narrow gauge. This is where the detector can be sited.

The lower tank can be a 5 litre carboy or similar.

The upper tank is the reactor. The biodiesel is continously circulated to reduce the glycerol to minimal level. The c.s. area of the flow in the separator is relatively large, to have low flow velocity to encourage good separation.

As the contents have continuous circulation, there should be no need for a cone bottom shape in the upper tank.

This message has been edited. Last edited by: GrahamLaming,

Small scale? was this a typo? or did your first attempt just seem to work on the small scale.. How hard would it be to scale it up to work? what would you do differently?

I may be looking at this wrong, but it seems to me that the pump would be trying to pull from the glycerol container as well. And that the flow from the pump would keep the contaminants in suspension. My two pennies. Cue

http://www.cbsenergy.com/eocs.htm

They already exist sort of.

I am not referring to the process of removing contaminants with an electrostatic field just the placement of the pump in the drawing

Hi cue

There are 2 things which help prevent flow into the pump from the glycerol tank.

1. The balancing tube is much narrower in comparison to the main pump inlet and outlet tube, so the tendency is for flow to take the easisest route. There is a downward flow of glycerol into the lower tank and a small upward flow of less contaminated biodiesel thru the balancing tube. There is also an upward flow of biodiesel in the larger tube just below the separator.

2. The glycerol is much denser than the biodiesel and seeks the lower level.

It falls freely down against an upwards flow of biodiesel, when the biodiesel velocity is lower than the natural fall velocity of the glycerol. This is why the cross sectional area of the separator is large compared the cross sectional area of the pipe, to reduce crossflow velocity. The horizontal component of the separator helps to separate the two flows also.

The dynamics are simple and should be reasonably easy to scale up.

Hope that helps.

HI Graham,
I found my lab PSU (eventualy) its only 3ma not 20 as I thought. So think its a long way short of the 100s of ma that I think my glycerin cell is going to need. Do you think its going to do the job on the soap cell.
I just tried to take pic of glassware for you but I need better light. I need to repair the compound slide on my lathe before I can turn up the end clamps but I making good progress on the reactor ( see pic of oscillator) So I hope to be able to test the seperator early in Jan.

Do you hapen to know of any Allen Bradley Flex i/o analogue modules? I particularly after 1794-IT8 thermocouple modules.

Tim

I keep geting this error when I try to post a pick. its only small 105K. how do I make this work
There was an FTP (file transfer) error. The detail is 'Upload to '/testdir/test.txt' failed. Detail: '552 Transfer aborted. Disk quota exceeded

As it is a balancing act do you have some numbers;flow;dimensions;tank capacities;cell size;electrode size and placement;voltage;current etc we can use to replicate this?

Graham, thank you for explaining that to me. cue

Hi Ant

No, I've nothing in the way of definite numbers, all empirical.

However, there are some methods which let you get better separation than a simple parallel pair of plates in a plain cell can offer, for a given throughput and cell size.

You want to segregate the glycerol from the biodiesel as soon as you can, so it is not re-introduced by the turbulence of the through-flow.

You can do this a number of ways ...

1. Run the flow horizontally over a honeycomb or other flow arrestor. As soon as the dropped glycerol enters the cells it ceases to have any horizontal motion. It can be easily collected from beneath the honeycomb, a non-turbulent area.

2. Have the electrostatic cell within a simple low velocity cyclone. The clumped glycerol congregates readily and can be diverted to a non-turbulent area. Try this in a jam-jar, there's a nice, clear effect to see.

Has anyone else tried this experiment yet?

Hi Tim,

Give it a try, all the same - you'll still get separation, may need to rethink the electrode layout, though. Start wide, getting closer together near the end.

As to the AB I/O boards, no, sorry, can't help there. Not a range I've ever used.

If you want to email the pics to...

grahamlaming at hotmail dot com

I'll post them for you.

Regards,

Hi evilpsych

I've only tried this on small scale volumes so far, not on my normal processor.

As soon as I have some spare time, over the Xmas break, I'm going to make a separator for the normal reactor. I've a fair amount of experience now, with a few litres of volume, and think I know what will work well for a 100 litre system.

I'll let you know and post pics and results when I get to that stage.

Hi Tim AU

You wrote ...

quote:

I just tried to take pic of glassware for you but I need better light. I need to repair the compound slide on my lathe before I can turn up the end clamps but I making good progress on the reactor ( see pic of oscillator) So I hope to be able to test the seperator early in Jan.

Here is Tim's photo of his continuous process flow oscillator ...

This message has been edited. Last edited by: GrahamLaming,

be more interesting with some details of what everything is.

I have plenty of that stainless pipe with the RJT fittings. But what is all the stuff attached to it and what is it doing?

Hi Ant, And thanks Graham for posting pic ( I trake it this forum permits only links to private hosting)

The section on the left is the inlet manafold, it has 2 x 1/2 BSP ports that will connect to my metering pumps, it also houses the first 3 mixer bafffles, the thing on top both sides is a thermocouple in a thermowell for process control and monitoring. The section on the right is the outlet, its identical to the inlet but with only one connection port on the botom.

Note process flow does not pass through the central oscillator section, instead 24 m of 2" ss pipe with 250 3mm ss lasercut baffel disks. these are spaced at 1.5 D and restrict area to 1/D.

The actual oscillator is 2 modified 50mm bore SS pneumatic cylinders( my original and far more elegant design was going to use a single magneticany coupled rodless ram) These are unfortunatly very expensive and not that easy to find used.

Each cylinder has one end cut off and replaced with a slightly bored out 2" BMS fitting and a teflon slave piston with 2 O rings to protect the aluminium piston from the caustic process.

The 2 bits at the back are a 3 phase gear motor from an industrial conveyer and a single to 3 phase inverter VFD for speed controll.

The remaining stuff is just mechanical linkage it incorporates a taper lock slide so I can set my oscilation amplitude at will.


Yesterday I finaly found a big enough rodless unit of the right type on ebay so when it gets here from the US I will build my original design as well. I will then be able to add my methanol / cat in 2 stages seperated by a second glycerin removal stage in order to shift reaction equilibrium for greater conversion.

Tim