Hail The Mighty Thumper

[haggy]

I have run several different cases on the model to test if the matrix results given in my March 24 post can be used for other 13% ABV pot conditions. Can we scale them up or down?

The 10 gal - 13% ABV pot charge at 2 kW was scaled down to 5 gal at 1 kW. Three levels of thumper ABV charge ( water, wash and low wines ) were run at 2.5 gal and 1 gal charge thus giving the same 0.5 and 0.2 T/P ratio as before. Then the 0.06 and 0.8 T/P ratios were run only for 13% wash. Here is the matrix of both the 10 gal and 5 gal run conditions for comparison of the results.

Conclusions:

1. The Distillate Starting ABV for the 5 gal runs are the same as the 10 gal runs for nearly all the run conditions in the matrix. Only a very low T/P of 0.06 had a different ( 5% points higher ) Starting ABV.

2. The Cumulative ABV at 20% out the spout for the 5 gal runs are within 1% point of the 10 gal runs for nearly all the run conditions in the matrix. Only a very low T/P of 0.06 had a different ( 6% points higher ) Starting ABV.

3. The Gal made at 60% ABV out the spout for 5 gal runs most all are about half the amount of the 10 gal run. As expected. Only one case was a little higher. So a direct scale up or down can be made for the "hearts".

4. The Gal made at 20% ABV out the spout for 5 gal runs most all are about 9% higher than half the amount of the 10 gal run. So a direct scale up or down + 9% can be made for the "tails".

5. Run time to 20% out the spout was the same for one set, T/P =0.2 where the heat losses were the same ( 39% ). In the other sets, the run time varied with the heat losses. A 15% lower heat loss gave a 9% lower run time. With less heat loss in the thumper, more gal are boiled over and we get to the end faster. The low T/P = 0.06 case gave a longer run time for the scaled down case which had higher heat losses. So, run time to 20% for scale up or down is dependent on each runs heat loss.

So, in most cases, we can scale the previous results to other 13% pot conditions keeping the same kW ratio. Heat losses can change the run time.


Then there was the question of how a change in the kW affects the run time and other run results. Is it in direct proportion? I took the original 10 gal - 13%ABV pot at 2 kW run at T/P of 0.5 and changed the kW to 2.5, a 25% increase. This was done for three levels of ABV in the thumper. Here are those results.

Thumper (a) Start Distillate %ABV (b) Cumulative %ABV to 20% and (c) Gal to 60% out the spout were about the same for each kW used. The Gal made to 20%ABV was about 9% higher.

Heat losses in this case were different ( lower ) than the original case ( 49% down to 42% ) . We expected the run times to be about 20 % less than the original case , they were about 25% lower. Less heat losses gave more vapor boil up and a shorter run time.

[haggy]

This post will examine different thumper conditions for a 10 gal pot with a 40% ABV low wines charge . I will do model calculations for a matrix of thumper conditions with this pot charge. This is like a spirit run. You can compare these results with my post of March 24 where I used 10 gal and 13% ABV pot charge.

The same method is used with the same matrix of thumper conditions: three ABV amounts, 0% water, 13% wash and 40% low wines and four levels of T/P ( thumper to pot gal ratio). So we will have a 3 x 4 matrix of run conditions at 40% ABV pot to evaluate and see the distillate results and how they compare with the previous cases 13% ABV pot of March 24.

All run conditions were at 2 kW and with some reflux ( Reflux Option set to 1 ). If a thumper has more reflux, the ABV results would be higher. The constant 42% heat loss option of the model was used. This is about the average value seen in run data. For stills with higher or lower heat losses, the gal made should be adjusted.

Here is the matrix of results, a lot of information. I will graph some of the main results so we can see how things change.

The same graphs as before are attached for comparison. The x axis is the thumper charge ABV and the curves are for different T/P ratios. The data points are for water, 13% wash, and 40% low wines.

This first graph is for the effects of the variables ( thumper charge ABV and T/P ratio ) on the Initial Distillate ABV.

The next graph is for the effects of the variables on the Cumulative ABV at 60%ABV out the spout. This might be the end point for the hearts made.

The next graph is for the effects of the variables on the Cumulative ABV at 20%ABV out the spout. Maybe you stop the tails at this point.

Next is the Distillate Gal made down to 60% ABV out the spout to give an estimate of the gal of hearts made ( after subtracting out some heads). A linear increase vs thumper ABV for all T/P ratios.

Next is the Distillate Gal made down to to 20% ABV out the spout. A linear increase vs thumper ABV for all T/P ratios. With very low T/P ( not much alcohol to start with ) the amount made is not increased much over the range of start %ABV.

These matrix results put numbers on the different options for a 40% ABV pot charge and can be used as a reference.

Calculated run times and ml/min initially out the spout are given in the matrix table. Run times are not that much different between these cases because of all the alcohol in the pot. Thumper fill up is a little more than before because the rate of vapor coming from the pot is higher.

So, these are examples of different types of spirit runs. I hope this agrees reasonably well with your still results. Remember, these graphs are for a 40 % pot charge and the previous post on March 24 was for 13% ABV. You can interpolate between the graphs for a different pot ABV charge. Adjustments for a different pot gal charge and kW are described in the March 24 post.

Anyway, the graphs give you a good idea of the changes and trends that can result due to changes in the thumper feed.

If you get all of this you should be working with me in developing and confirming this pot/thumper model. A distillate ABV vs run time graph is given in the next post. No more room here.

[haggy]

Here is the thumper distillate ABV vs run time graph for the above post with 40% ABV in the pot and 13% ABV in the thumper. This is a spirit run where the ABV stays fairly constant for much of the hearts made. The different curves are for different thumper gal to the pot gal ratios. A low T/P ratio charge gets you a higher ABV but will make less product. See the above post graphs for the gal made at each T/P ratio.

[haggy]

Thumper Fill Calculations

When running the above Matrix with the pot/thumper model, I noticed some results that could lead to overfilling the thumper. This was during a spirit run when the pot charge was high in ABV (40%) and the thumper had a low ABV charge (water or 13%) and T/P was less than 0.2.

I do not have much posted run data on thumper fill for this worst type of starting run conditions. Only one run P12 of the Kareltje data set was at about these worst conditions. The model prediction of the ending thumper fill amount fit that data but the pot charge was only 2.33 gal at 34% ABV.

The amount of heat losses can greatly affect the thumper fill. High thumper heat losses will result in more pot vapor condensed in the thumper, a lower vapor rate out the thumper and higher thumper filling.

So, I ran another set of spirit run calculations with several starting pot gal all at 40% ABV, with low thumper starting gal (T/P<0.2) and ABV less than 13% and found the maximum thumper gal rise during a run. I varied the heat losses to get a range of results. Here are the results for an average heat loss (which fit several data sets ) and 20-15% lower and higher heat losses.

The thumper maximum gal rise increases linearly as the pot gal increases ( more vapor comes over to the thumper ). The maximum rise is about the same for thumper charge ABV's below 25% and a little less above 25%. The maximum rise is about the same for all T/P gal ratios less than 0.2, and a little less above that ratio.

Heat losses are a major factor and will reduce or increase the thumper fill significantly. A well insulated thumper with less heat loss should not fill as high as one not insulated.

So, to estimate a thumper maximum fill, take the pot gal charge and use the average heat loss curve to find the maximum rise on the chart and add that to the start thumper fill plus some headspace. The thumper should have sufficient volume to cover this amount.

Example
A 10 gal and 40% ABV pot charge with a 3 gal thumper charge and average heat loss could fill up to 5.4 gal (3 charge+2.4 rise ). So a thumper volume would need to be at least 6+ to run these conditions.

Example
A 5 gal and 40%ABV pot charge with a 0.1 gal (just enough to cover the inlet pipe) thumper charge over a range of heat losses could rise up between 0.80 to 1.2 gal. A 2 gal thumper volume is ok if you use a low thumper charge.

Summary
Based on the model calculations for a slow spirit run with a higher heat loss, the thumper gal rise is about 29% of the pot gal for all pot gal cases. To get a total thumper % of pot amount, we need to add the initial thumper charge and the headspace. For a minimum initial charge of 2% ( .1gal/5gal above example ) of the pot and 10% of the pot headspace, we get about 41% of the pot gal for the total thumper fill required.

These calculations help to quantify what goes on with the thumper filling and they agree with the "rule of thumb from experience that the thumper size should be at least 40% the size of the pot." The thumper volume should be even higher or the same size if you start the thumper with a higher gal charge.

I also ran a set of strip runs going down to 20%ABV out the spout. They have about the same thumper fill maximum amount as the spirit run. The maximum rise in a spirit run occurs in the middle of the run, where the strip run maximum rise is at the end of the run. The same 40% of pot size rule of thumb applies for the strip run also.