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Automation Questions

captnops
edited December 2014 in Configuration

Hi folks. I have a 2" sectional plated column and I am learning on this before stepping up to a larger StillDragon model. I am interested in automating the running of the still and looking for help. I would like to control the reflux coolant based on vapor temp and not sure where to start. I believe that the best places to measure temp are top of column BEFORE RC, just after RC and (for accuracy's sake) somewhere downstream of the PC. How does one automate coolant based on temp and what parts would I need?

Thanks

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Comments

  • CothermanDistilling

    I use a BCS-462, you can search this forum for it.

    I measure boiler, boiler vapor, below RC, above RC, RC water, and PC water.

    You can control the RC or PC based upon the exit water temperature using a danfoss thermostatic valve, or a 4-20mA PID controller and valve... browse through the topics and you should find quite a bit...

  • grim
    edited December 2014

    I'd recommend not trying to control the reflux condenser flow based on the vapor temperature, instead suggest that you control the reflux condenser flow using the coolant temperature directly (what @CothermanDistilling mentioned). Simply monitor vapor temp above the reflux condenser, and use your judgement to adjust as the reflux condenser temp as necessary.

    The end result, will actually be very similar though. As the run progresses, the heat load on the reflux condenser will increase, and the controller will need to increase the flow rate through the condenser to maintain the set point. This will increase the reflux ratio through the run, putting the still into a quasi "constant product quality" mode. Output rates will fall as this takes place (as more distillate is being recycled as reflux). This is very different from maintaining a set coolant flow through the full run, which will result in the reflux ratio staying somewhat static (vapor temps will increase since the boiler abv is falling and reflux ratio isn't being increased).

    As you get further into the run you may need to drop the reflux condenser temperature a bit to pull the vapor temps down, but as you get into the tails you are going to hit a point at which you simply can't maintain output rates, since you start nearing 100% reflux.

  • captnops

    Thank you both for the information

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