Abstract: This study focuses on the technology for recovering DMAC in wastewater from production of fatty acid ester of vitamin C,which contains about 30% of DMAC.The rectification method and the extraction method are simulated on different experimental devices respectively.As for the rectification method,a stainless steel packed tower with a height-diameter ratio of 18:1 is employed,which is filled with structured packing with surface area of 500 m2/m3 and an effective height of 1.6 m.Wastewater boiled to gas is fed at a speed of 1 000 g·h-1 and the optimum reflux ratio determined is 1:1.5.As for the extraction method,methylisopropylketone is chosen as the extractant to extracting DMAC,which is also used to extract fatty acid ester of vitamin C.The optimal extraction ratio is 2:1 and the best pH value is 7.After six-stage countercurrent extraction to wastewater,extractant is distilled and trace water is removed with toluene azeotropy.The energy consumption in recovering DMAC in 1 000 kg of wastewater is 916 248.4 kJ for the extraction method and 3 950 100 kJ for the rectification method.By each method,DMAC,as a reused esterification solvent,can be recovered with a recovery rate of more than 96%.However,the extraction method consumes lower energy and exhibits a lower recovery cost than the rectification method.Therefore,the extraction method is more industrially valuable.
林洪, 黄凯, 林智岭. 维生素C酯生产废水中DMAC的回收技术[J]. 现代化工, 2019, 39(4): 178-181.
LIN Hong, HUANG Kai, LIN Zhi-ling. Recovery technology of DMAC in wastewater from vitamin C ester production. Modern Chemical Industry, 2019, 39(4): 178-181.