低温等离子体预处理对油田废水蒸发及蒸馏水品质的影响

Influence of non-thermal plasma pretreatment on heavy oil wastewater evaporation and the quality of the distilled water

为了提高油田稠油废水蒸发回收的蒸馏水的品质并防止蒸发过程中的结垢,利用低温等离子体对稠油废水进行预处理,使之与低温等离子体产生的离子和自由基反应后再送入蒸发器,研究了稠油废水经过等离子体预处理后蒸馏水各项指标的变化和蒸发过程中结垢的分布变化。结果表明:经过等离子体预处理后废水中的二氧化硅含量和硬度下降,更适合蒸发处理;同时蒸馏水中所含盐和油的含量都减少了,品质得以提高。此外蒸浓缩到30～40倍时,经过等离子体处理后废水的浓缩液中固体悬浮物大幅升高;对应地,蒸发器底部结垢大幅降低。对比所获得的蒸馏水各项指标与注气锅炉的给水指标,可以看出蒸馏水所含的油分超标是蒸馏水回收为锅炉给水的最大障碍;而低温等离子体预处理可为解决油田大量稠油废水回收蒸馏水的结垢问题和水质问题提供了一个快捷的新途径。

In order to improve distilled water quality so that it can be used as oil field boiler feeding water and avoid scale formation during the evaporation process,the technology of non-thermal plasma（NTP） was employed in this research to pre-treat heavy oil wastewater before evaporation.First the wastewater was sprayed into NTP reactor tube with atomizers and contacted with ion ＆ free radicals,and then it was sent to the evaporator.It was found that after pretreatment,the contents of SiO2,hardness,metal contents,oil and salinity of pretreated wastewater were reduced.Accordingly,all of these indexes of distilled water from wastewater evaporation decreased too;and for the left concentrated solution which was around 40 times concentrated,suspended solids in the solution increased greatly;while scale formation on the evaporator surface was inhibited.When compared the quality of distilled water with the requirements on oil field injection boiler feedwater,it was found that the quality of distilled water from wastewater evaporation met all the requirements except for the oil content.Low-temperature plasma,as a pretreatment technology,will improve quality of feedwater and prevent fouling during evaporation,