Anhydrous Piperazine Separation Technology Was Studied

The synthesis route of piperazine and its application were introduced briefly in this thesis, and then we summed up the separation process of piperazine at home and abroad. With the study of a great deal of references and on the basis of preliminary research in laboratory, we use the residual curve to judge the feasibility range of distillation. Through determination of ethylenediamine-water system of gas-liquid equilibrium data, the vapor-liquid equilibrium curve for binary systems of cyclohexane-ethylenediamine and cyclohexane-water were estimated by Aspen Plus. Choosing cyclohexane as the entrainer, we made the mixed solution of the crude product of piperazine azeotropic distillation, in order to remove ethylenediamine and water. Finally, we obtained piperazine products with mass fraction of96.33%and triethylenediamine with mass fraction of97.65%, and achieved the entrainer recycling with water for extraction solvent, the liquid volume ratio of cyclohexane and water is5:3.On the basis of the batch distillation experiments, we designed that the separation process of industrialization about the output of piperazine was1000t/a, the output of triethylenediamine was680t/a. Aspen plus software was applied to simulate the separation process so as to design the industrialization process flow. The sensitivity analytic module is used for theoretical tower, feeding position and reflux rato parameters optimization of the columan. The mass fraction of piperazine reaches to98.20%and the recovered reaches to97.28%, triethylenediamine obtained98.90%and the recovered obtained93.67%.Based on the stimulation data of Aspen Plus, we use Tray Sizing and Tray Rating module to design the distillation column and accounting. The patterns of all the column is sieve plat with single flow, which is used commonly in the chemical separation. Using Aspen HTFS+software to design and calculation the preheater, cooler and reboiler and selected the right size models to the heat exchanger and other equiqment. The results showed that optimization design and the working condition of the column as follows.1. Dehydrating tower of theoretical plates number is22, the feeding position for plates is10, the inside diameter is0.68m, the plate spacing is0.45m, the biggest flooding factor is0.7914, the reflux ratio is0.7, the distillation ratio is0.7892.2. The azeotropic rectification tower of theoretical plates number is19, the feeding position for plates of raw material and cyclohexane is6and17, the inside diameter is0.68m, the plate spacing is0.45m, the biggest flooding factor is0.7681, the reflux ratio is0.4, the distillation ratio is0.9319.3. The piperazine distillation column of theoretical plates number is23, the feeding position for plates is14, the inside diameter is0.36m, the plate spacing is0.30m, the biggest flooding factor is0.7848, the reflux ratio is4.0, the distillation ratio is0.6604.4. The triethylenediamine distillation column of theoretical plates number is15, the feeding position for plates is8, the inside diameter is0.22m, the plate spacing is0.20m, the biggest flooding factor is0.7557, the reflux ratio is1.0, the distillation ratio is0.9770.