Gasification furnace black water treatment process

Abstract

The invention relates to a gasification furnace black water treatment process which comprises the following steps: black water enters a sedimentation tank, and a flocculating agent is added into the sedimentation tank; effluent of the sedimentation tank enters a grey water tank, and a scale inhibitor is added into the grey water tank; effluent of the ash water tank sequentially passes through an aerophoresis coagulation tank, an aerophoresis reaction tank, a curing reaction tank, a precipitation clarification tank and a PH regulating tank and then enters a deaerator, wherein aeration is carried out in the aerophoresis coagulation tank, a coagulant is added, and the PH value of water in the aerophoresis coagulation tank is adjusted to 10.5 or above; aeration is carried out in the aerophoresis coagulation tank, and a reaction agent is added; a flocculating agent is added into the curing reaction tank; and in the PH regulating tank, the PH value of the water is adjusted to 7-9. The sewage treatment system has the advantages that circulating water is not prone to scaling, and the effect of reducing impact of discharged water on a rear-end sewage treatment system is achieved.

Description

technical field [0001] The present application relates to the field of gasifier black ash water treatment, in particular to a gasifier black water treatment process. Background technique [0002] In the current coal gasification plant process, the coal gasification black water is firstly treated by sedimentation in a large settling tank, which mainly removes a large amount of suspended solids in the gasification black water by adding a cationic flocculant; then enters the gray water tank, where Add scale inhibitors to the gray water tank to control the scaling tendency of gasification circulating water; return most of the treated gray water to the front-end circulation system, and discharge a small amount; control by continuously discharging gray water and replenishing fresh water The salt content of the whole system and the balance of hardness, silicon, ammonia nitrogen, etc. [0003] The characteristics of gray water are that the temperature is higher, generally 50-80°C, ...

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Problems solved by technology

[0004] In view of the above-mentioned related technologies, the inventor believes that due to the nature and characteristics of gray water, there will be the following problems: (1) gray water is used as circulating water, and its hardness is too high, resulting in serious fouling of the entire system pipeline of the gasification device, frequent equipment blockage, The operation stability is not good, and the inspection and maintenance workload is cumbersome; (2) Excessive hardness in the discharged gray water will lead to serious fouling of the biochemical unit in the back-end sewage treatment system, resulting in poor activity of microorganisms in the sewage due to calcification of activated sludge , reducing the efficiency of biological denitrification and decarbonization

(3) The large fluctuations of ammonia nitrogen in the discharged gray water may exceed the capacity of the sewage treatment plant, resulting in impact on the biochemical system, and the discharge of ammonia nitrogen cannot meet the standard

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