Hi everybody, I want to design two industrial vacuum distillation systems. The dimension of my distillation tanks are as follow: (1) A Horizontal Cylinder Tank with 200 cm length and 200cm diameter (total volume = 6300 liter) (2) A Horizontal Cylinder Tank with 400 cm length and 290cm diameter (total volume = 26500 liter) The material for both systems is Black Iron Sheet. The pressure and the temperature I want to work at are in the range of 0.1-0.07 mbar and 200-350 degree of centigrade. But I don’t know what wall thickness for the distillation systems is safe? By the way, I am an organic chemistry expert, so I don’t know much about design of distillation systems (which is an engineering problem).