广州石化延迟焦化含硫污水的处理技术探讨

分析了中国石油化工股份有限公司广州分公司延迟焦化装置分馏塔顶的含硫污水的性质,其中COD平均值超过20 000 mg/L。经过汽提处理后,净化水中的COD仍较高,平均值超过3 000 mg/L。认为污水汽提装置净化水COD较高的主要原因是焦化装置含硫污水和蒸馏装置电脱盐含硫污水中富含低分子羧酸类化合物,其易溶于水而难于被汽提和电脱盐装置去除。对净化水进行了模拟汽提和活性炭吸附试验,结果表明,再汽提或活性炭吸附的办法难于再大幅度降低COD。建议采用湿式催化氧化工艺处理焦化含硫污水或采用污水汽提净化水代替焦化蒸汽大吹汽,不仅可以减少蒸汽耗量和污水排放量,还可降低装置能耗。

Discussion on treatment technology for sour water from delayed coking unit in Guangzhou Petrochemical Company

The properties of sour water from overhead of fractionator of the delayed coking unit in SINOPEC Guangzhou Company are analyzed,and average chemical oxygen demand (COD) of the water is found to be higher than 20 000 mg/L.After treatment in the stripper,the COD of the treated water is still high,and the average value is higher than 3 000 mg/L.The analysis concludes that the high COD of treated water is the result of the low molecular carboxylic acids rich in the sour waters from delayed coking unit and from electric desalting of crude unit.These carboxylic acids can easily dissolve in the water and it is difficult to remove it by the stripping or the electric desalting process.The simulation stripping and the active carbon adsorption experiment for the treated water are carried out,and the results demonstrate that the repeated stripping or activated carbon adsorption is difficult to greatly reduce the COD again.It is recommended to apply wet catalytic oxidation process to treat the sour water from delayed coking unit,or the treated water is used to replace steam in steaming out in delayed coking unit.This may not only reduce the steam consumption and waste water production but also lower the energy consumption of the unit.