由于粗苯酐中所含的蒽醌及其同系物等重组分含量极少，在反应工段中没有对其

Because the content of heavy components such as anthraquinone and its homologues contained in the crude phthalic anhydride is very small, no material is calculated in the reaction section, and the boiling point is very different from the phthalic anhydride, which is easy to remove and has little effect on the product. Moreover, the impurities in the crude phthalic anhydride are basically removed after rectification in the light component tower, which can meet the design requirements. Therefore, this design only introduces the heavy component tower in the phthalic anhydride distillation section, and does not make calculations. Furthermore, in the material balance calculation of the phthalic anhydride rectification section in this chapter, it can be approximated that the phthalic anhydride melt extracted from the bottom of the light component tower is the product phthalic anhydride (ie stream 3). Similarly, in the design calculation section of the distillation column in this design, only the light component column is considered.

Because the recombinant fraction content of the bourgenand and its congeners is very small, there is no calculation of the material in the reaction section, and the boiling point and benzene is very different, easy to remove, the impact on the product is not great, and the impurities in the crude benzene after the light component tower distillation basically removed, can meet the design requirements. Therefore, this design of benzene distillation section of the recombinant sub-tower only for the introduction, not calculated. Further, in this chapter of the benzene distillation section of the material accounting, it can be considered as approximately the light component of the tatabottom extracted benzene melt is the product benzene (i.e. logistics 3). Similarly, the design calculation section of the distillation tower in this design is considered only in the light component tower.

Because the content of anthraquinone and its homologues in crude phthalic anhydride is very small, there is no calculation of the materials in the reaction section, and the boiling point is very different from that of phthalic anhydride, which is easy to remove and has little impact on the product. Moreover, the impurities in crude phthalic anhydride are basically removed after distillation in light component tower, which can meet the design requirements. Therefore, this design only introduces the recombiner in the rectification section of phthalic anhydride, without calculation. In this chapter, when calculating the material balance of phthalic anhydride distillation section, it can be approximately considered that the phthalic anhydride molten solution extracted from the bottom of the light component tower is the product phthalic anhydride (i.e. logistics 3). Similarly, in this design, only the light component tower is considered in the design and calculation section of distillation tower.<br>