Process and device for treating tail gas and/or residual liquid in polycrystalline silicon production

Abstract

The invention discloses a process and device for treating tail gas and / or residual liquid in polycrystalline silicon production. According to the process, firstly, the tail gas and / or the residual liquid are fed into an elution column, weak-acid water with the mass concentration being 2-5% is used for carrying out spraying and washing at a countercurrent state, washed gas enters a liquid sealing tank to be purified through clean water, the finally released gas is discharged into air, and washed liquid serves as weak-acid water to carry out circular spraying; after the weak-acid water for circular spraying in the first step exceeds the limited concentration, part of waste acid water is drained, water is added to dilute the weak-acid water until the needed concentration is achieved, then, the weak-acid water continues to be used, lime emulsion is added into the exhausted waste acid water to neutralize the exhaust waste acid water, then, a pressure filter is used for carrying out filtering, part of filtrate is reused, and other filtrate and filter residues are discharged. The process and the device ensure that the treated tail gas reaches the standard and then is discharged; blockage of a spray head, a pipeline and equipment is avoided, and operation is safe and easy; part of the filtrate is reused, the chemical engineering waste acetylene sludge emulsion is recovered and used, the water consumption is reduced, and the treating cost for tail and / or residual liquid is saved.

Description

technical field [0001] The invention belongs to the field of tail gas and residual liquid treatment in polysilicon production, and in particular relates to a tail gas and / or residual liquid treatment process and device in polysilicon production. Background technique [0002] At present, in the tail gas treatment of polysilicon production, in the water-sealed airtight equipment, two-stage purification treatment is adopted. The first stage uses 10% lime emulsion to circulate and spray under the condition of downstream flow, and the second stage uses 10% lime emulsion circulated in the liquid-sealed tank. % Lime emulsion purification, the generated non-condensable gas is emptied; when the circulating liquid is PH=6-9, it is directly sent to the filter press for solid-liquid separation, the filtrate is discharged, and the waste residue is directly transported out. The residual liquid treatment is to neutralize with 10% lime emulsion in a nitrogen sealed closed equipment with a s...

AI Technical Summary

Problems solved by technology

[0003] In the process of treating tail gas and residual liquid with 10% lime emulsion, due to the agglomeration of hydrolyzate, it is easy to cause blockage of equipment, pipes and nozzles; after blockage, the effect of equipment washing is not good, the absorption of tail gas is not complete, and the discharge The tail gas is difficult to meet the standard, and the workload of cleaning the blockage is heavy, the load is heavy, and the waste of materials is serious

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