苯酐是重要的化工原料，目前國內外苯酐的方法主要有萘氧化法和鄰二甲苯氧化法，兩種方法在苯酐凈化過程中都有黑褐色精餾殘渣產生。該廢料中含有大量苯酐，同時含有部分黑色焦油和高聚物，無法進行直接利用。
Phthalic anhydride is an important chemical raw material. At present, the main production methods of phthalic anhydride at home and abroad are naphthalene oxidation and o-xylene oxidation. In the purification process of phthalic anhydride, black brown distillation residue is produced in both methods. The waste contains a large amount of phthalic anhydride, part of black tar and high polymer, which can not be used directly.
目前有各種回收方法，其中比較多的有溶劑萃取法、升華法和反應深加工處理法等。但各種工藝均不能很好的滿足實際要求。本研究按某廠提出的產品不含焦油、收率高、成本低的要求，采用簡單合理的回收工藝可回收幾乎廢料中的全部苯酐，產品質量好。
At present, there are a variety of recovery methods, including solvent extraction, sublimation and deep processing. But all kinds of production processes can not meet the actual requirements. According to the requirements of tar free, high yield and low cost of the product proposed by a factory, almost all phthalic anhydride in the waste can be recovered by simple and reasonable recovery process, and the product quality is good.
采用該法處理回收某廠苯酐廢料600噸，可年產粗苯酐近500噸，再結合工廠的需要將該苯酐返回到苯酐裝置出工業優級品，不影響苯酐裝置的正常。
By using this method, 600 tons of phthalic anhydride waste can be recovered from a factory, with an annual output of nearly 500 tons of crude phthalic anhydride. Combined with the needs of the factory, the phthalic anhydride can be returned to the phthalic anhydride production unit to produce industrial high-grade products without affecting the normal production of the phthalic anhydride unit.
該技術可降低苯酐成本，為工廠帶來一定的經濟效益。目前國內苯酐能力估計為70萬噸，按2%計算可年產廢料1.4萬噸，估計可回收1萬多噸苯酐。若該技術推廣全國或向國外轉化技術將具有很好的經濟和社會效益。該技術成熟，達到水平。
This technology can reduce the production cost of phthalic anhydride and bring certain economic benefits to the factory. At present, the domestic production capacity of phthalic anhydride is estimated to be 700000 tons. Based on 2%, the annual output of waste material is 14000 tons, and it is estimated that more than 10000 tons of phthalic anhydride can be recovered. If the technology is extended to the whole country or transformed to foreign countries, it will have good economic and social benefits. The technology is mature and has reached the international advanced level.
