高浓度含酚废水资源化利用

采用两次酚醛缩合-尿醛缩合的方法处理含酚废水,实验室小试考察了酚醛一次缩合的甲醛用量、二次缩合的反应温度、时间、甲醛用量及催化剂含量对除酚效果的影响;尿素投料批数、反应时间、反应温度和尿素/甲醛摩尔比对除醛效果的影响.一次缩合后酚含量可降至8 000 mg/L以下,酚回收率为88.6%.二次缩合后废水酚含量可降至50 mg/L以下,两次缩合后酚总回收率达99.0%,缩合回收的酚醛树脂可作为生产原料回用.用与甲醛等摩尔比的尿素处理两次缩合后的废水,甲醛含量可降至300 mg/L以下,可直接生化处理.中试验证试验表明其结果优于小试,说明小试实验数据可靠.中试试验初步经济衡算表明,每吨废水回收约50 kg酚醛树脂,扣除生产原料和水电等成本费用可获毛利260元左右,具有良好的经济效益.

Utilization of high concentration phenol-containing wastewater

The phenols in phenolic wastewater are treated by twice phenol-formaldehyde and urea-formaldehyde condensation process.We investigated the effect of factors such as formaldehyde consumption in the first phenol-formaldehyde condensation,temperature and time of reaction,consumption of formaldehyde and catalyst in the second condensation on phenol removal,and then studied the effect of factors such as urea feeding times,temperature and time of reaction and urea molar ratio in urea-formaldehyde condensation on formaldehyde removal in laboratory.The phenol content is less than 8 000 mg/L and the phenol recovery is 88.6% after the first condensation while it is less than 50 mg/L after the second condensation,the twice condensation phenol recovery reaches to 99%.Condensation of phenol-formaldehyde resin can be used as a raw material.Formaldehyde content of the wastewater after condensation treated with urea is less than 300 mg/L,so that the wastewater can be treated directly by biochemical method.Pilot-scale validation results are better than the small scale,indicating that small scale experimental data is reliable.Pilot-scale preliminary economic accounting shows that every ton of wastewater can be recycled about 50 kg phenolic resin,the gross profit may be around 260 Yuan deducting the cost of raw materials and utilities.The method of twice phenol-formaldehyde and urea-formaldehyde condensation has a good economic benefit.