Apparatus for separation and purification of saturated hydrocarbon and method for separation and purification

A separation and purification apparatus for an unsaturated hydrocarbon comprising;

• an extractive distillation tower supplied with feedstock containing unsaturated hydrocarbon and a solvent for distilling the feedstock to separate and purify a target unsaturated hydrocarbon;
• an impurity concentration detecting means for detecting a concentration of a specific impurity other than the target unsaturated hydrocarbon at the extractive distillation tower or another tower connected to the extractive distillation tower;
• a target unsaturated hydrocarbon concentration detecting means for detecting a concentration of the target unsaturated hydrocarbon at the extractive distillation tower or another tower connected to the extractive distillation tower;
• a return ratio control means for controlling a flow rate of part of a fluid including the target unsaturated hydrocarbon taken out from a bottom of the extractive distillation tower and returned to the extractive distillation tower;
• a solvent flow control means for controlling a flow rate of the solvent fed to the extractive distillation tower;
• a reflux ratio control means for controlling a flow rate or part of a residual component of the feed stock taken out from a top of the extractive distillation tower and refluxed to the extractive distillation tower,
• a bottom temperature control means for controlling a bottom temperature of the extractive distillation tower;
• and
• a predictive control means for calculating forecasted values of the concentration of the specific impurity and the concentration of the target unsaturated hydrocarbon based on values detected by the impurity concentration detecting means and target unsaturated hydrocarbon concentration detecting means and controlling the return ratio control means, solvent ratio control means, reflux ratio control means, and bottom temperature control means based on the forecasted values.