化工专业英语（河北科技大学）unit 6 lesson01.pptVIP

Unit 6 (1) Azeotropic and Extractive DistillationCorrection:1.P120 line 3, “diffcult” should be read “difficult”2.P120 line 6, “rolatilities” should be read “volatilities”3.P122 line 2 from bottom, “givencolumn” should be read “given column” 恒沸蒸馏一种特殊的蒸馏方法。当溶液中各组分相对挥发度很小或为恒沸物时，一般精馏难以使组分分离，通过加入第三组分(称为挟带剂或分离剂)与原混合液中某一组分形成一组新的最低恒沸物，从而加大了组分间相对挥发度，塔顶、塔底分别得到新的最低恒沸物和另一组分，使原混合液得到分离。 萃取蒸馏是化学上常用的分离液体混合物的实验方法，原理是用化合物在两种互不相溶（或微溶）的溶剂中溶解度或分配系数的不同，使化合物从一种溶剂内转移到另外一种溶剂中。经过反复多次萃取，将绝大部分的化合物提取出来。 Many mixtures are difficult to separate by distillation because their relative volatilities（相对挥发度）are close to接近1.0. Some of these mixtures may be separated by the addition of another component that increase the relative volatilities of the original constituents. 许多混合物的相对挥发度接近于1.0，因此很难用蒸馏的方法将它们分离。当加入另外一种组分后，就可以增大初始组分的相对挥发度，而使一些这样的混合物得到分离。 Fractionation精馏after the addition of a component to increase relative volatilities is referred to as（称为）azeotropic distillation恒沸蒸馏or as extractive distillation萃取蒸馏, depending upon the nature of the added component. 加入一个组分增加相对挥发度的的蒸馏称为恒沸蒸馏或萃取蒸馏（这取决于加入组分的性质）。 In azeotropic distillation the added component is relatively volatile易挥发的, so that it appears in the distillate蒸馏液；馏出物. In many cases it forms low-boiling-point azeotrope最低共沸物with one of the original component. 在恒沸蒸馏中，加入的组分挥发度较高，因此它出现在馏出物中。在多数情况下，它与一种初始组分形成最低共沸物。 The low-boiling azeotrope goes overhead in the distillate, and the remaining剩余物, 残余components go out at the bottoms. 最低共沸物上升到蒸馏液中，而剩余组分从塔底排出。 Of course, it is then necessary to separate the azeotropic agent恒沸剂from the original component by an appropriate separation process过程, 方法. 当然，随后还必须采用适当的分离方法将恒沸剂与原有组分分离。 Extractive distillation involves the addition of a relatively nonvolatile 不挥发的, 非挥发性的component. The “solvent” added flows downward from stage to stage, increasing the relative volatilities相对挥发度. It finally flows out with the bottoms. 萃取蒸馏加入的则是不挥发性的组分。加入的“溶剂”逐板向下流动，在此过程中增加了相对挥发度，它最终从塔底流出。 Azeotropic (distillation)恒沸蒸馏or extracti