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meerkat last won the day on May 3 2020

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  1. It is quite a calculation to convert the lower flammability limit figure of 3.3% into kg or litres of ethanol. At only 3.3 % we can regard the 1600 m3 as pure air to make the calculation easier. At 25 C and atmospheric pressure the density of air is 1.18 kg/m3 and the 1600 m3 will contain 1888 kg of air. The 3.3% is in terms of molar percent (same as volume % at this temperature and pressure) so we need to convert the mass of air to moles. The molecular mass (molecular weight in the US) of air is 29 so the 1600 m3 contains 65 kgmols of air. The 3.3% would be 2.15 kgmols of ethanol
  2. The Snap 41 measures SG only and will be confused by the sugar. Ignore the results you get from this unit. The Alex 500 is designed to measure solids as well as alcohol but the web page does not say how it does it. The fact that it does not work well for high (> 50 abv) alcohol levels suggests that it is using Refractive Index as its second measurement because I know that the mathematics for combining SG and RI does not work well for high abv. You should give Anton Paar a call and ask them if the Alex 500 is suitable for your application - I believe that it is.
  3. For spirits containing alcohol and water only, you can determine the alcohol content by measuring either the density or the refractive index of the spirit. Adding sugar will impact on these readings and you cannot use the standard tables. The sugar changes the density in the opposite direction to the alcohol, but it moves the refractive index in the same direction as the alcohol. These 2 opposing effects can be combined mathematically to determine the abv and the sugar content at the same time. There are machines from Anton Paar and Rudolph Research that do this, but they are not accepted b
  4. If you are in the US and subject to TTB regulations then the only accepted way to proof something with 5% sugar is by using the TTB lab distillation procedure. There are no chemical, instrument or software methods that I am aware of that would be acceptable. The software will certainly speed up the process of getting to the target proof, but the final product will always have to be gauged using the TTB procedure.
  5. Pumping the bottoms from the second column to the top of the first is a closer match to a single tall column - but whether it is better or worse than the double defleg arrangement I do not know.
  6. I only have experience with one column where the tray spacing was deliberately made very tight. It was a very difficult column to operate and never achieved its design capacity. Unless you have a very skilled designer with a proven track record I would stay away from tight tray spacing. Split columns are common and there are many vendors who can offer you these. I would be interested in reading how pumping the bottom liquid from the second column to the top of the first to provide its reflux compares with using a dephlegmator to provide the reflux on the first column.
  7. Something I didn't mention before, but which will apply to both @mors9 and @Skaalvenn, is that horizontal piping that can contain vapor and liquid at the same time should always be sloped down in the direction of liquid flow and never be truly horizontal. This is well understood by civil engineers and domestic plumbers, but we process people sometimes forget it. Ideally we want the liquid level in the base of the column to be a couple of inches above the base (which would make the drain pipe full of liquid), but because loads vary this cannot be guaranteed and at some stage the level will
  8. That all sounds fine to me. The last thing that I can think of checking is if there are anti-siphon holes drilled either in the elbows just inside the boiler or just below them. If there are anti-siphon holes but no U-bend seals in the drain pipes immediately below the columns it could cause a problem. If you have anti-siphon holes then you should also have U-bend seals. From the spurting behavior and the vapor bubbles in the returning wash it really looks as though there is vapor getting into the return lines. If there are no anti-siphon holes or other openings above the liquid level
  9. How far do the return pipes project under the liquid level in the boiler? Are there any U-bends or seals in the return piping inside the column skirt (i.e. in the section of pipe that cannot be seen in the video)? How far above the boiler liquid level is the entrance point to the drain pipe at the bottom of each column? Do you have any pressure measurements?
  10. This is a common problem in still arrangements like you have. The solution proposed by @Stumpy's will solve the problem but you may get away with a less complicated arrangement. In the photo posted by Stumpy's the base of the second column is below the liquid level in the boiler and it was essential to use a pump in his case. If your columns are sufficiently above the liquid in the boiler you might not need a pump. A similar problem was discussed in https://adiforums.com/topic/11969-return-line-to-pot-question/ where the photo shows the column bases higher than the boiler. In that threa
  11. A rotavap is a very useful piece of kit, but I have had customers (of my software) get confused by the readings. By pulling a vacuum the boiling point of the solution is lowered and it is important to realize that this also means that the condensing point is lowered. If the cooling water on the condenser is not sufficiently cold for the vacuum you are using some alcohol can be lost in the condenser. It has no effect on the solids left in the evaporator bulb so the solids analysis will be correct, but you may lose alcohol and get an incorrectly low proof when proofing the condensed spirit.
  12. In the US the TTB distillation method is the only officially acceptable method of proofing. But as PeteB has pointed out, if you have two separate measurements of two independent properties (i.e. density and RI in the case of the Rudolph machine) you can combine them with the applicable math and get to an accurate, but unofficial result. You can do a similar procedure using much cheaper, but also much slower, equipment than the Rudolph AlcoTest. With a simple drying oven and an accurate weighing scale you can measure the solids content after the infusion. Once the sugar content is known it
  13. I think @PeteB is correct regarding the reactions being faster in the liquid phase. I have seen large continuous vodka columns which were made of stainless steel, but the reflux was passed through a bed of copper raschig rings before returning to the column.
  14. I have been supplying engineering software (including a units conversion program) to the US for 30 years, and alcohol blending software for 15 years. Over this period I have seen a gradual shift towards metric units in the US and the eventual total switch over is inevitable. You have already switched to 750 ml bottles to match the rest of the world, and the other changes will not be much more difficult. I think that being proactive about it is the right way to go. Apart from the actual units, the basis of the ABV measurement will have to be changed from 60 °F to 20 °C as the reference t
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