The invention provides an oil refining alkali dreg waste liquid
processing method including the following steps: (1)
sulfuric acid is used for acidification of alkali dreg waste liquid, and
nitrogen is introduced; before pH is decreased to 11-9.5, acidified
tail gas produced by acidification is discharged into a condensing device, gas discharged by the condensing device is returned to an acidification device to be used as a carrier gas; acidification is continued to be performed until the pH value is dropped to 7-8, acidified
tail gas produced by the acidification section is discharged into a
sulfur recovery plant for the production of
sulfur; acidified
tail gas produced after the acidification section is totally returned to the acidification device to be used as the carrier gas; (2) when the alkali dreg waste liquid pH value is dropped to 2-7, acidification is stopped, and
oil phase is separated; (3) the waste water with the
oil phase recovered is extracted; (4) after extraction, acidic liquid is processed with
sodium hydroxide, the
sodium hydroxide is added according to the final concentration of alkali of 20wt%-50wt%, and precipitate is isolated to obtain an alkali liquor capable of being reused. The oil refining alkali dreg waste
water processing method can effectively recover
sulfur resources,
sodium resources and
phenols in alkali dreg waste water, reduces COD of the waste liquid without production of high
salt content and high COD waste liquid, and avoids
impact to the
sewage treatment field; meanwhile recovered lye can be reused for oil product alkali washing refining and extractant regeneration, and the zero
discharge of the alkali dreg waste water can be realized.