This calculator is for 2", 3" and 4" diameter packed reflux columns installed over a potstill. Operating results are given for an equivalent theoretical plate column design. The distillate product ABV % is estimated using a table of values, you make an estimate of the expected distillate ABV% in the input data.
You enter the input data for the column and include a desired or observed prodcut distillate rate. The calculator will determine the reflux ratio for this operation. It can also be used to find a distillate rate that will give a certain reflux ratio or run time.
This calculator also gives an estimate of several other operating characteristics for a packed reflux column using the specified input data. Distillation time starts after the column reaches equilibrium.
The results are for an operation where the watts and reflux ratio are not increased during the run. When they are increased to keep the distillate rate more constant, the time to tails will be different.
The run time to reach tails is estimated. Calculations are then made for the amount and % ABV of heads and hearts produced up to the start of tails. The calculations are not to be used for fast strip runs.
The results are based on run data from real run data, several HD posts, calculations from a simulation of a packed reflux column and established distillation column design equations. Estimates are made for possible flooding conditions ( Yes / No ) and the efficiency of the column. The results can be used to study your operation.
The vapor rate to the condenser is calculated from the pot watts and the abv % of the vapor from the top plate or packing. You make an estimate of this abv% in the input data and can update it if needed. A heat loss of 30% is used in the calculation.
For a CM column, you must change the Cooling Water Flow Rate Input Data so that the Condenser Heat Transfer Watts about equal the Heat Transfer Required Watts in the Calculated Results Section for the CM Dephleg Condenser. Then you have the required Cooling Water Flow Rate.
For a VM or CCVM column, adjust the Cooling Water Flow Rate so that the Cooling Water Exit Temperature is about 115 F to 120 F. This will subcool the reflux a little. But be sure there is enough cooling water flow so there is no alcohol vapor escaping through the condenser.
An estimate of the total still heat loss is a required input. For very well insulated pot and column, use 20% heat loss. For average insulation or not the pot insulated, use 30% heat loss. For uninsulated stills, use 36% to 40% heat loss.
You specify and input the dessign details of either a shotgun or Dimroth condenser. A shotgun condenser can be used for a CM or VM column, and a Dimroth coil condenser can be used for a CM, VM or CCVM column. A good size CM shotgun defleg condenser for a 2" column has 0.45 ft^2 surface area. A good size CCVM coil condenser for a 2" column has at least 80 inches of 3/8 inch copper tubing or at least 0.65 ft^2 surface area.
Information about this calculator can be found in the thread "Reflux Condenser Sizing - Packed Columns".