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Semi - Automation of hybrid still

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Hi guys,

I'm running a 250litre 3 plate hybrid still.  It's heated with electrical elements.

I want to get it semi-automated so that I don't need to be tweaking reflux condenser and heat input all the time.  The other advantage is the ability to pre-heat wash prior to distilling, we intend to get 2 runs done per day.  We also have a wash pre-heater that will be heated at a set time.

I'm proposing to build a panel with a PLC controller.

I intend to have PT100's in the pot and one in each condenser respectively.

Do I need to regulate the vapour temperature or am I over complicating the setup?

I attach a photo of the still that we're going to hard plumb shortly.

Any advice greatly appreciated.

20171206_131859.jpg

20171206_131918.jpg

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you'll watn to control deph output temp.  PID + solenoid valve is the cheapest way to go. Put the valve on the red pex line coming out of your deph.  Use search. plenty of folks doing the same thing.

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Red line on the deph is completely wrong and you will have a terrible time running the still.  That is assuming red is hot and blue is cold.

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MGL is correct, flow in the bottom and out the top in order to automatically purge the air.

how it is currently set up 75% of your cooling surface are will not be used

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I would personally not want to automate this still, specifically because of its small diameter.  It's like asking something small to do something really big and this is when things start costing lots of money.

 

My two cents worth would be change to a LM type of collection with dephleg on top and collection below, flowing out through a needle valve to a PC.  So the the only items being controlled are the heat and reflux control with the needle valve.  Far simpler.

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If that set of vicegrips is on valve or other outlet a simple Watts quick vent would do the trick.  As is, the drain on the bottom will cause fits but if you modulate flow on the out/bottom side all will be fine.

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Preheat in the still?  To save time?

Obligatory cautionary statement - Don't even think of attempting to let that still heat up unattended.

I second many of the comments posted above.  I suspect it would be less expensive and less of a headache to simply purchase a larger still if you are looking to save time.  A decent PLC system with a good HMI, and all associated instrumentation, valving, input modules, output modules, could easily run north of $1500-2000 for just parts.  Depending on the PLC system, you might even need to purchase the programming software and hardware interfaces, which isn't cheap, then spend the time educating yourself on the system.

PID dephlegmator control will give you 75% of the magic of a fancy PLC automation system, at 1/10th the price.

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Thanks everyone for all the feedback.  Why wouldn't people go with any automation?  Some clever automation will increase productivity and lessen the  burden of constantly changing dephlegmator, I'm aware that this is partly due to the way it's currently plumbed.  I will look into the PID dephlegmator control, thanks for the heads up.

Why wouldn't I think of letting the still heat up unattended if appropriate safety measures are in place?  My hot liquor tank is programmed to keep a constant temperature, the same could be applied to the still.  Most of the Irish and Scottish distileries pre-heat their wash in a wash charger/ heater why wouldn't I?  Provided safety measures are put in place I don't see it as a big no no.

People run their stills twice or 3 times daily, heat up is a lot of time 'wasted'.  With a wash charger, you can cut out 1.5 hours on each distillation run.

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Also just as a side note, I couldn't find any posts in relation to PID or solenoid valves. Anyone have any links?  Much appreciated.

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1 hour ago, Silk City Distillers said:

I suspect it would be less expensive and less of a headache to simply purchase a larger still if you are looking to save time

Or make money.

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1 hour ago, Silk City Distillers said:

Preheat in the still?  To save time?

Obligatory cautionary statement - Don't even think of attempting to let that still heat up unattended.

I second many of the comments posted above.  I suspect it would be less expensive and less of a headache to simply purchase a larger still if you are looking to save time.  A decent PLC system with a good HMI, and all associated instrumentation, valving, input modules, output modules, could easily run north of $1500-2000 for just parts.  Depending on the PLC system, you might even need to purchase the programming software and hardware interfaces, which isn't cheap, then spend the time educating yourself on the system.

PID dephlegmator control will give you 75% of the magic of a fancy PLC automation system, at 1/10th the price.

Silk city is correct, no still should ever be ran unattended.  Another option for dephlegmator control is a thermostatic valve.  You just set the temp slide on the valve and the valve will maintain the outgoing dephlegmator cooling temp without a power source or control module.  They make things really simple.

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The mechanical thermostatic valves would be great if the probe end wasn't so damn big (Talking Danfoss AVTA, the KING of self-acting valves).

For  someone without fabrication capability, they are impossible to use as they are too big to fit in the condenser, or plumbing.

If someone would fabricate a flow-through housing that could be easily plumbed into the output plumbing of a condenser, that would be fantastic.  A nice one-piece unit.  Even better if it has the adjustable bleed for the control valve necessary when you locate the probe away from the process temp.

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Regarding mechnical TVs,  how accurate are they?  Are PMs / calibration required?   We looked at a Danfoss and the probe size was 3/8 x nearly 6".  I had no idea what to do with it.  Went the omega / belimo route.

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2 hours ago, Silk City Distillers said:

The mechanical thermostatic valves would be great if the probe end wasn't so damn big (Talking Danfoss AVTA, the KING of self-acting valves).

For  someone without fabrication capability, they are impossible to use as they are too big to fit in the condenser, or plumbing.

If someone would fabricate a flow-through housing that could be easily plumbed into the output plumbing of a condenser, that would be fantastic.  A nice one-piece unit.  Even better if it has the adjustable bleed for the control valve necessary when you locate the probe away from the process temp.

The thermostatic valves work in a proportional fashion and they work great which is why companies like Kothe, Mueller and so many others use them.   Also they are much safer, because there is no electricity involved. We have a temp probe housing for the Danfoss thermostatic valves that goes on the output side of your condenser.  The price is $125.00 each for the temp probe housing.  We can adapt the temp probe housing to fit any connection and that is built into the price.

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4 hours ago, Silk City Distillers said:

Danfoss is probably +-2 to 3c.

Oooh. That's a lot. I can see these would have place in the product condenser. Plumbing would be trivial as well. 

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Here is a good primer for the AVTA on the product condenser - Cotherman has done a lot of work here.  Very old thread, but the approach for external mounting would be roughly the same.

https://www.stilldragon.org/discussion/213/thermostatic-valve-installation-on-product-condenser

Danfoss FJVA would be a good alternative on the PC, forgot about that one.

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Indyspirits and silk city,

 

Yep, you run from the product condenser through the temp probe housing over to the dephlegmator which gives you great condenser and dephlegmator control.  That's how the Germans do it and how we do it as well.  We first tried running with the thermowell on the output side of the dephlegmator and that did not work well, but it works perfectly this way, but you guys thought it was only for final condense control huh?  The difference between us is the fact that I have designed and built over 240 stills for distilleries and you have not.   I sometimes control up to 3 dephlegmators on the same still using these valves.

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