Coal gasification ash water treatment method

Abstract

The invention relates to a coal gasification ash water treatment method. The problem that in the prior art, gasified fine residue is too high in carbon residue and reused ash water contains plenty of suspended particles is solved mainly. The ash water treatment method comprises the steps that black water coming from a gasification furnace and a washing tower undergoes two-stage or three-stage flash evaporation and concentration and then enters a thickener; under the stirring effect, the black water coming from the thickener is divided into two layers, floating bead slurry of the upper layer overflows and enters an ash water circulation system or a sedimentation tank after floating beads are separated; the concentrated black water of the lower layer enters a carbon residue classifier, carbon residue undergoes floatation, tailing slurry of a lower layer of a floatator; supernatant of a settling tank enters the ash water circulation system, and lower layer turbidity solution of the settling tank enters a filter to be dehydrated to obtain filter cake (gasified fine residue). By adopting the ash water treatment method, the carbon residue content of the coal gasified fine residue can be reduced, the utilization of the gasified fine residue is facilitated, and the suspended particles in reused ash water can be reduced.

Description

technical field [0001] The invention relates to a coal gasification ash water treatment method, in particular to an ash water treatment method for entrained gas wet slag removal. Background technique [0002] In the entrained bed gasifier, coal and gasification agent react chemically, which can transform coal into fuel gas or chemical synthesis gas. At present, the Texaco gasifier process using coal water slurry as raw material and the Shell gasifier process using dry pulverized coal as raw material are often used. Both gasification processes can operate safely and stably, but there are still some problems to be solved in their gray water treatment methods. [0003] The fuel gas or synthesis gas produced from the coal gasifier is called crude gas, which contains a large amount of fly ash. At present, the relatively mature crude gas purification process is a wet purification process, which uses water to quench and wash the crude gas to remove fly ash and acid gas in the cru...

AI Technical Summary

Problems solved by technology

[0012] In view of the above-mentioned problems and deficiencies in the prior art, the object of the present invention is to provide a coal gasification ash water treatment method, which effectively solves the problem of gasification fine slag and residual carbon separated by settling tanks and subsequent filtering devices. High content and many floating beads in reused gray water, the problem that pipes and filters are easy to clog

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