Method and system for treatment of oil shale distillation sewage

Abstract

The invention discloses a method and system for treatment of oil shale dry distillation sewage. The method and system can be used for treating dry distillation sewage generated during a shale rendering process; the system comprises a pre-treatment unit, a biochemical processing unit and an advanced treatment unit which are connected in sequence, wherein the pre-treatment unit comprises an adjusting tank, a mixing reaction tank, an oil separated sedimentation tank and an air floatation tank which are connected in sequence; the biochemical processing unit comprises a hydrolysis acidification tank and a primary MBR tank which are connected in sequence; the advanced treatment unit comprises an advanced oxidation system, a secondary MBR tank and a nanofiltration system which are connected in sequence. The method comprises pre-treatment, biochemical treat and advanced treatment. The method solves the problem that pollutants in oil shale distillation sewage are high in concentration and difficult to treat; pollutant contents are effectively reduced; pollution to environment is avoided; the method realizes efficient treatment on oil shale distillation sewage, and has the advantages that the method is stable in operation, high in treatment efficiency, low in running cost, and convenient to operate and maintain.

Description

technical field [0001] The invention relates to the field of sewage treatment for environmental protection, in particular to a method and system for treating oil shale dry distillation sewage containing oil, high ammonia nitrogen and high concentration of organic matter. Background technique [0002] Oil shale is a companion to stripped coal seams, and is a solid combustible mineral that can produce shale oil similar to natural petroleum through low-temperature dry distillation. Shale oil refinery dry distillation wastewater mainly comes from certain oily, organic matter, ammonia nitrogen and other pollutant wastewater generated during the production process of shale oil refineries. The carbonization temperature of shale oil refinery is generally 500-550°C. The sewage generated during the carbonization process contains a wide variety of pollutants and complex components. The sewage not only contains petroleum, but also contains a large amount of ammonia nitrogen, naphthenic ...

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Problems solved by technology

[0004] At present, in the field of shale oil dry distillation sewage treatment, some shale refineries have poor sewage treatment system facilities, unreasonable selection of pretreatment process systems and equipment, and poor oil and slag removal effects, resulting in the failure of subsequent biochemical process units. , thus failing to achieve the expected treatment effect, or even completely paralyzed, useless

In addition, the main problem that oil shale retort sewage treatment is difficult to meet the standard is the high concentration of ammonia nitrogen. In the past, stripping ammonia distillation and stripping methods were often used to pretreat high ammonia nitrogen wastewater. Among them, the steam consumption of ammonia distillation tower used in stripping ammonia distillation The amount is generally 100 ~ 170kg / m 3 Sewage, this method has high energy consumption, and is restricted by the amount of steam in the boiler. The shale oil refinery cannot be equipped with stripping ammonia treatment facilities; and there are many deficiencies in the denitrification method of the stripping tower, which consumes a lot of energy, The denitrification efficiency is low, and an ammonia absorption or recovery device is required, which also increases the difficulty of removing ammonia nitrogen by physical and chemical methods

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