StillSmart

Not sure where to put this so perhaps someone could move it.

This might be of interest to the builders out there. This table relates to SPP packed columns producing azeotrope, but the volumes are valid for any packing operating in that condition. It isn't mine, it originated with one of the SPP manaufacturers.

So if your column is going to be producing neutral, it indicates the boiler vapour output, and product output speed, per kW of power applied.

Obviously this is a guide because it can't factor in heat loss from the boiler and column. Still interesting though.

Cheers Myles...a year ago this would have been gobbledygook to me...but as I'm getting better at what I do, it now makes sense.
This will now be cut & pasted into my scrapbook.

Makes sense and I understand it, though I'm not sure about applying it to my situation/kit......

This seemed like the best home for this topic.
I am open to suggestions.

Robert.

Intresting table but it doesn't specify the diameter of the cloumn, in guessing it's for a 2" column as the numbers kind of work for that.

I read somewhere the other week that a boiler with a 30% charge produces 46 litres of vapour per hour so it's interesting that 46 ml/(kw*min) is there in the 29% column.

I'm not sure the formula works as written, the way it's written will decrease the vapour as the power is increased, so instead of ml divided by (kw*min), it's ml per (kw*min)

So if I've got this right, in one hour a 29% wash with 1.5 kW power will produce

46ml per (1.5x60)
= 4.1 litres an hour of vapour

And the take off rate should be

18ml per (1.5x60)
=1.62 litres per hour take off

These numbers, especially for the takeoff rate match what you would expect off a 2" column

Actually I believe the numbers work with any size column because the quantity of vapour produced is dependent on power input. And also because these numbers are specifically for a column that is producing azeotrope.

You are correct about the ml per kw*min and that was probably just a typo from source.

If you increase the power to match what is used on a bigger column lets say 3kw on a 3" column, with a 40% charge, then you get a figure of 3780 ml/hr and that fits right into the reported averages.

3" column, 2.5 to 3.8 litres per hour, on 2.5 kW to 3 kW.

These numbers do not work with with any other product ABV, you have to use different tables for those.

I didn't think to work it out with other power levels but like you say, it works for all sizes.

It's good to know what take off rate to be aiming for depending on the power being used, on my last run I used my SPP for the first time, I was collecting a little faster than this but I was making it up as I went along, this info would have been very usefull, at least I was close, next time I'll try and be a bit more controlled, I'm also going to fit a thermometer on my boiler.