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Automation for moonshine still

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Automation for any moonshine still with a steamer
(I do not know how exactly the word for a can or a hollow cylinder at the outlet of the moonshine is translated into English, see the figure and diagrams).

Many people have questions about how you can make the work of a moonshine still fully automatic without using expensive solutions. (for example using Arduino).
I am collecting simple and unusual solutions that have been posted on the Internet by individual craftsmen in the past years.




I propose a simple experiment that can show you what happens to temperature changes in a "classic" moonshine still. The experiment was carried out on a small cube (10-25 liters), but the temperature values are very characteristic and you can rely on them in your experiments.

Main idea:
It is possible to track the beginning of the process and, in automatic mode, smoothly enter the working state of the moonshine still using three temperatures: the vapor at the top of the tank, the temperature in front of the can and after it.

An error of 0.5 degrees of temperature sensors is enough, for software processing of data from sensors this is more than enough.
The sensors are simply pressed against the pipe and thermally insulated with silicone. Since we are not interested in the exact temperature of the steam at these points, but only in its difference, I think this approach is appropriate.

So, the most interesting thing is the schedule for reaching the operating state during the test distillation, the purpose of which was to obtain temperature values in manual mode.



The graph shows the passage of steam from the distillation cube to the refrigerator, depending on the temperatures indicated above. It can be seen here that after 54 degrees at the entrance to the steam can, you need to be very careful and gradually reduce the power for a smoother exit to the operating mode.
We will be guided not by the value of the temperature, but by the difference in the readings of these two sensors, but it is still necessary to be tied to the readings of the sensor at the entrance to the steam chamber, say: the temperature is more than 50 and the difference is 24 degrees => we reduce the power.
The temperature difference allows you to ignore the atmospheric pressure.

The end of the exit of the "tails" will be in the region of 70-71 degrees, (see the graph), while this will be the same temperature of the sensor before and after the dry jar (the first can after the steam exits the tank).
The temperature in the tank at the end of the distillation can be 90-90.75 degrees Celsius, or, if you need all the "tails", then 95-97 degrees.

The author of this solution (experiment) recommended focusing on the following temperatures at the top of the tank:
68C - depending on the tank capacity, up to 30 minutes (acetone, methanol) leaves the tank.
79-80C - the main distillation process is underway.
above 80C - alcohol residues and tails come out.

Thanks for your attention.

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Second interesting idea,
maintain a constant boiling point of alcohol in the hollow column (we will rather focus on the upper point). We will try to predict the temperature change using the lower two sensors. Anything that has a lower temperature should condense directly back into the cube (reflux).



this is what we end up with: (this is a hydrometer with 94% alcohol content)

As practice has shown, the temperature in the reflux condenser cannot be the basis for controlling the distillation process. The problem is that it differs by 1 - 1.5C, depending on external conditions (room temperature, atmospheric pressure) and the type of distilled material (wine has some control boiling points, mash has others, mead has third, jam mash - fourth).

An interesting feature was noticed. The temperature of the copper air cooler (column, where the fan is on the diagram) changes in an interesting and strictly defined way: the temperature at the end of the distillation (precisely at this point of the cooler = closer to the end of the first heat exchanger) behaves as follows: it slowly rises to somewhere around 67- 69C, and then drops sharply to 46-47C (within 10-11 minutes). And after this drop in temperature, the outgoing alcohol, as they say, “does not burn” (all the alcohols are already partially gone, there is nothing to burn).
This temperature dip is explained, apparently, by the fact that the heat capacity of the boiling steam changes so that it is able to cool much earlier in the heat exchanger than the alcohol-containing steam. That is, there is more water in it and it condenses already at the first turns of the heat exchanger.

The design of the refrigerator can be as follows:

fixed 4 fans with a diameter of 140 mm from a computer at 12 volts. Heat exchangers cope with the task easily, there are no stagnant zones in them, they are straight-through. Toward the end of the first heat exchanger, a temperature sensor was attached, which controls the switching on of the refrigerator fans with a setpoint of 30C.



As a result, a control algorithm for the apparatus was formed:
1. We heat the distillation cube (about an hour - one and a half - depending on the external temperature of the environment and the volume of the apparatus, in the experiments a tank of 20-25 liters was used). We are not doing anything. We are waiting for the "heads" to appear. We are waiting for the electronic thermostat (in fact, a unique digital signal) to trigger, which is set to 30C. It was noticed that after turning on the thermostat, it does not turn off until the very end of the distillation process (if the outside air temperature is above zero). The actuation of the thermostat and the switching on of the column fans exactly coincides with the beginning of the "heads" outflow. We start the timer for 5 minutes (this time is always enough to drive off 200 ml of heads). After 5 minutes, we can begin to take away ethyl alcohol ("strong body"). We are waiting for 30 minutes. During this time, about 1 liter comes out (with a usual filling of a cube of 20 liters) of a strong "product" (60 percent ethyl alcohol).

2. We pass to the selection of "weak body" (low concentration of alcohol, "tails"). We distil for 1 hour (distillation of the "weak body" takes about 1 hour while the "alcohol is burning" - this is still somewhere around 1.5-2 liters). And during this hour we do nothing, but only fix the maximum temperature of the temperature sensor.
In general, the temperature on the column fan at this point can float within 53-69C, but not by 20C. At 20C, the temperature changes only at the end of the distillation and abruptly. For example, you recorded the maximum temperature on a column with a fan, let it be 69C. After driving off the "strong body", we begin to control the deviation from this temperature maximum. If another maximum is caught, fix it (write it down). And again we are waiting for a deviation from the maximum at 20-22C. As soon as the temperature drops below the level (for example, 69-21 = 48C), we switch to the “tails” distillation mode.

3. In the “tails” selection mode, simply set the timer, for example, for 1-1.5 hours and get as much as possible. During this time, all residues of alcohol will be distilled off anyway. After 1.5 hours, you can turn on some kind of alarm about the end of the process, and after - all equipment can be cooled down and turned off.


Real experiment:
Distilled 18 liters. Sugar mash.

0:00 - Start heating the distillation cube.
1:00 - Boil violently. The reflux condenser (column with fan) is warming up.
1:02 - Thermostat has tripped. The fans spun. The setting is 30 degrees for on, 28 for off. Heads began to flow.
1:06 - 250 ml. "Heads" drove away. 57-60C - steady-state temperature at the control point of the column with the fan.
1:30 - 1 liter of 60% alcohol solution distilled.
1:58 - 2.5 liters distilled off (1 liter of "strong body" and 1.5 liters of remnants of the "weak body"). The temperature slowly crept up.
2:03 - Temperature at the set point of the refrigerator 69.7C.
2:10 - The temperature slowly crept down.
2:16 - 66.3C.
2:24 - 58.3C.
2:28 - 55.0C.
2:29 - 54.0C.
2:30 - 52.2C.
2:31 - 51.0C.
2:32 - 48.0C.
2:33 - 46.0C.
2:35 - 46.2C - the end of the "weak body" distillation.
2:39 - 46.6C.
3:27 - 45.0C - the end of the "tails" stripping.
Experiment two:
The next time the distillation went the same way, only the temperature was shifted a little higher - it was warm in the room. But the 20C difference persisted. During the distillation process, two temperature jumps are observed - at the beginning to 63C and at the end to 69C with a drop between the peaks to 53C (one peak for methanol, the second for ethanol?). But in the end - all the same a failure, as I said, but sharp and at 20C from the maximum.

In general, in the course of experiments, I concluded that The key to controlling the distillation process is not the temperature in the distillation cube or dephlegmator, but the temperature at the desired point of the dephlegmator (only in a column with a fan, see the diagram-figure). The algorithm would be perfect if it were not for the low temperatures in the room. If the distillation takes place in the open air (if the distillation is going somewhere in the garage) around 0С, the algorithm "breaks down". The temperature at the thermostat temperature sensor drops below the on-off thresholds.

It was noticed that even with different brews, at different outside air temperatures, the time for distillation really differs, but this difference in the duration of the process consists only in the heating time of the tank with the contents and can go from 1 to 1.5 hours. The rest of the time of the distillation process practically does not change (with the same filling of the tank).

Thanks for your attention.




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