苯甲酸重副产物的脱色处理

Decoloration of Heavy By-product in Benzoic Acid Production

为了有效去除苯甲酸重副产物中含有的交联大分子和碳化物等有色杂质，降低有用组分资源化处理的难度，分别采用吸附和蒸馏两种方法对苯甲酸重副产物进行脱色处理。实验结果表明：大孔树脂、硅藻土、活性炭等作脱色剂不能有效去除苯甲酸重副产物中的有色杂质；在真空度0．093～0．095MPa、蒸馏温度220～240℃条件下进行蒸馏脱色，当温度出现回落时停止蒸馏，平均馏出率为66．99％；蒸馏脱色得到的轻组分颜色呈黄色，可满足中和、酸化、结晶、回收苯甲酸的要求；釜残物可作为燃料通过焚烧利用其热能。

In order to facilitate the recycling of the useful components, the heavy by-products in benzoic acid production were decolored by adsorption and distillation processes to remove the colored impurities such as crosslinking macromolecules and carbonized compounds. The experiment results show that the colored impurities cannot be removed by adsorption with macroporous resin, diatomite and activated carbon, but can be removed by distillation. Under the conditions of vacuum degree 0.093- 0.095 MPa, distillation temperature 220 -240℃ and distillation stopping when the temperature is begin to fall, the average distillation rate of the heavy by-product can reach 66.99%. The yellow light distillate can meet the requirements for neutralization, acidification, crystallization and benzoic acid recovery. Kettle waste could be used as fuel.