回收萘法苯酐生产废水中的富马酸

采用催化异构化、碱溶、脱色、酸析、过滤等工艺处理萘法苯酐生产废水,回收其中的富马酸。考察了碱的品种、碱溶pH、活性炭加入量、酸析pH等对富马酸产品外观质量和收率的影响。实验得到最佳工艺条件:采用氢氧化钠作为碱溶用碱,碱溶pH为6,活性炭加入量为0.5%(w),酸析pH为2。在此最佳工艺条件下制备的富马酸产品外观为白色,纯度达到99.1%,产品收率为72.8%。按30 kt/a苯酐生产装置计,每年可回收富马酸660 t,年利润429万元。

Recover of Fumaric Acid from Wastewater in Phthalic Anhydride Production by Naphthalene Method

The wastewater in phthalic anhydride production by naphthalene method was treated to recover fumaric acid by the processes of catalytic isomerization,alkali dissolution,decolorization,acid precipitation,filtration,and so on. The factors affecting the quality and yield of the product were studied. The optimum process conditions obtained through experiment are as follows: Using sodium hydroxide for alkali dissolution,pH 6 for alkali dissolution,activated carbon dosage 0.5%（w）,pH 2 for acid-precipitation. Fumaric acid prepared under the optimum conditions is a white product with 99.1% of the purity and 72.8% of the yield. With a 30 kt/a phthalic anhydride production device,660 t of fumaric acid can be recovered with 4.29×10⁶ yuan of profit per year.