Process Intensification for the Recovery of Hydrogen Cyanide in the Andrussow Process

The aim of this work was to determine a cost-optimal design of the distillation unit of the Andrussow process. For this purpose, a feed with a mass flow rate of 121 t h^?1 and a concentration of ca. 2 wt % hydrogen cyanide (HCN) was considered. An approach for a cost-optimal process intensification was developed with the goal to achieve the desired product qualities, while minimizing the organonitrile accumulation in the column. For this purpose, the simple distillation column of the established cost-optimal design of the base case was extended to a configuration with a side stripper with taking into consideration heat integration in the process. It was found that this new configuration allows a much smaller accumulation of organonitriles in the main column; reducing thereby the operation issues of the process while decreasing considerably the total annual cost of the distillation unit by 61 % as compared to that of the base case design.