How to select and assign variables for a distillation column that is equipped with both a secondary condenser and a side stream extraction?

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Simulating a distillation column equipped with both a secondary condenser and a side draw presents convergence problems; I think the main issue is the difficulty in finding appropriate set values. Taking the distillation of the material obtained after ethylene hydrogenation to remove acetylene in an ethylene tower as an example, the main product, ethylene, is recovered from a side stream, while the non-condensable gas, hydrogen, is collected after secondary condensation. To reduce ethylene losses, the temperature of the first condenser is generally set higher, while that of the second condenser is set lower. Assume that the materials to be extracted from the top of the tower or via side streams are: 98 kmol/h of ethylene, and only 2 kmol/h of hydrogen ； Assuming that the temperature of the second-stage condenser is -10 degrees, with a gas phase composition of 2 kmol/h of hydrogen and 0.5 kmol/h of ethylene, then 97.5 kmol/h of ethylene needs to be extracted via the side stream. If I set the side-line withdrawal rate at 96 kmol/h and also specify that the temperature of the secondary condenser be -10 degrees, then 2 kmol/h of hydrogen and 2 kmol/h of ethylene must be withdrawn from the top of the tower; it seems difficult to achieve such a high concentration of ethylene in the gas stream at -10 degrees. My understanding is that a side-stream production rate of 96 kmol/h is unreasonable, but I’m not sure what the actual value should be. How do you decide on the appropriate value for this variable?