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indyspirits

Emergency Product Condenser Water Supply

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We're getting a closed loop glycol system for our distillery expansion. One feature I want to put in place is a secondary thermostatic mechanical valve that will sense the output water temp of the product condenser and if it exceeds a specific temp, open up municipal water flow the PC.  Anyone doing something like this an want to share their experience?

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Danfoss has sensors that can perform this sort of task (and they have a great logo)...you might consider a simple thermos-sensor that will open the switch to turn off your boiler should you loose condenser cooling water....or Automation Direct's https://www.automationdirect.com/adc/Shopping/Catalog/Process_Control_-a-_Measurement/Temperature_-z-_Process_Controllers/1-z-4_DIN_Size_(SL9696_Series)...

pay close attention to the variant of the "SL" series you choose should you run down that trail...

 

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Not sure how you would do this mechanically, as something like a Danfoss AVTA would open the supply, but then you would flood your glycol system with water.

We have a surface mount RTD temp sensor on our parrot to measure distillate temp, connected to a Watlow limit controller.  The limit controller just screams and blinks today, but originally we were going to wire it into our steam control to cut steam to the boiler.  You could use it to switch two solenoids to switch the PC to muni water feed, and then drain down to your flood drains, etc.  We figured it was easiest to just shut down the still on a distillate high-temp (vapor) situation.

 

 

 

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AS Silk City said, if you are running glycol in your system you won't want to 'cross the streams' so to speak as you will be diluting the glycol, which can be added back, but is expensive. Perhaps you place a plate exchanger that is on a thermostatic valve to temper your inlet water to your setpoint. Chill loop on one side, city water on the other. The glycol side always runs through, but if it gets over your setpoint, it is chilled again with city water. 

Another thought, is you could pipe it like we have with our mash cooler. We run a tube and shell with a pair of three way valves. Set both valves in position 'A' and we run well water through the cooler, to be preheated for our next cook, stored in a insulated tank. Once we collect what we need, we switch to Position 'B' which closes the loop, but adds a plate exchanger which is on our chiller loop. We turn on the loop pump and it recirculates the well water between the two exchangers. This way our mash cooler only ever sees potable water, but we can use our chiller loop or well water to chill the cook. You could set something like this up with a thermostatic valve to temper the inlet temperature, but the loop pump would need a bypass. You could also put a manual override on it so you can preheat city water if you need it, and not use the chiller system at all.

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The biggest question is the ROI - How much money is implementing the system likely to save you in lost downtime? I would think if you're in an urban area 2-3 days and you would be able to get most simpler stuff fixed. If you're more rural then if might take longer. (Repair Days) * (Number of failures yearly) * (Labor lost) = basic yearly "Downtime" cost. 

 

- How often do you think the Chiller is going to break down?  

- How long do you think it would take to get something simple fixed? (Repair guy local? Parts? Common brand/size of cooler vs exotic/odd size?) 

- Is the emergency system itself likely to cause failures? (It appears to be getting complicated. The more complicated something is the more likely it is going to break.)

- Are you going to test it? How often? 

- If the system is activated will it affect the glycol system and will you have to do maintenance on it after?  At what cost? 

- Will the system be able to cover workflow 100% while the chiller is down? 

 

 

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All very well thought out responses.  More than anything I'm trying to mitigate to uses cases:

  1. The process loop pump craps out and the boiler is on
  2. We lose electricity at the facility

Regarding 1 -- The temp sensor on the parrot that would open a mechanical relay (or relays) on the boiler is most straightforward and not too bad to implement. I had thought about adding a flow meter to the output side of the PC but that adds complexity unnecessarily. 

Number 2 is more difficult. If we lose power to the facility I can think of no other way to address the risk other than a purely mechanical temp controlled valve.  After going a bit of Googling I came across this valve which may do the trick -- fully configurable and mechanical. I just spoke with a pre-sales engineer. I'll report back with pricing... Still need to deal with diluting the glycol water mixture. However, with a 2500 gallon reservoir and the fact that this would only be open long enough to condense the vapor created by residual heat is that an issue??

 

 

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2 condensers is your easiest and cheapest option.  First one being glycol and 2nd one being water.

Flow meter and temp sensor on the glycol/ distillate output.  Flow drops to X or temp rises to X and it opens the water valve to the 2nd condenser. That way you eliminate contamination of either system.

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if the condenser is over temperature then you are at risk of venting high proof vapor that can burn or explode. The boiler should be killed and an alarm set.

the Danfoss AVTA will control water or glycol in the nominal range.   the fail-safe should (must) work with a no power situation in your facility.  

this little puppy will get the emergency off switch away from the vapor filling the still house and switch your boiler off....https://www.grainger.com/product/DAYTON-Line-Volt-Mechanical-Tstat-6EDY7?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/2NNR5_AS01?$smthumb$&breadcrumbCatId=1000071

 

 

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1 hour ago, indyspirits said:

All very well thought out responses.  More than anything I'm trying to mitigate to uses cases:

  1. The process loop pump craps out and the boiler is on
  2. We lose electricity at the facility

You could put a normally closed valve that requires power before the control steam valve, you set up a Johnson style controller  that sends power to the valve, opening it, if your condenser water is at an acceptable temp (heat mode, and you set your max allowable). If the water is good temp and you have electricity at your facility it allows steam to your still. If either of those conditions are met, it loses power and springs back closed. Shutting off the boiler is an issue because there could be a lot of steam in your system still, continuing to heat.

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In the past, I have supplied these type systems to hospitals for emergency cooling for MRI equipment in case the cooling chiller fails- it's a matter of control valves and for interfacing with a glycol system, you must have a city water to glycol heat exchanger to prevent city water from entering the glycol loop, making a mess of your process loop!

It's fairly pricey if done as automatic sensing system, but not so much if a manual switchover is involved.

Call me if you want details and a budget $$.

Mike Gronski, 678-773-2794

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I'd use an electrostatic flow sensor running off a 24v power supply, with a battery backup and 24v nc/no coolant shunt circuit. As soon as you have normal coolant flow, you switch it on as a failsafe. If flow stops, it cuts out a portion of the glycol loop, and runs city water...also beeps really loud. You could set it to shut down steam, too... I'd use a pilot valve for that instead of a solenoid. 

 

You could make it automatic with a heat trigger or time delay as well. Interesting idea. I might take the time to make a schematic. 

 

Dan

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After much internal debate / discussion / deliberation / arguing we've decided to go with the simplest solution -- two three way valves; the first will select the input coolant source -- glycol or municipal water and the second value will select the output flow -- either back to the cold water reservoir or to sewer.  Although automated solutions were tempting, the thought of validation and periodic testing and the fact that the still will never run without staff in the building (obviously) led us to the manual solution.

 

 

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Make sure you install a strainer on the inlet of the city water- always winds up you have sediment in the city water line.

 

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