Efficient water-washing dechlorinating technology and device for household waste incineration fly ash

Abstract

The invention relates to the technical field of fly ash treatment, in particular to an efficient water-washing dechlorinating technology for household waste incineration fly ash. The efficient water-washing dechlorinating technology comprises the following steps that S1, by means of multi-point multi-frequency sampling and analysis, the chlorine content in the fly ash is analyzed; S2, according tothe analysis results in the step S1, the flow rate of washing water is determined according to the water-ash ratio of 2-4:1; S3, water washing is conducted on the fly ash with a multi-stage counter-flow water washing technology, and the filtrate obtained after each stage of the multi-stage counter-flow water washing treatment is used as the washing water of the last stage of water washing; and S4, after the multi-stage counter-flow water washing operation is completed, solid-liquid separation is carried out, and the solid is conveyed to high-temperature melting / cement kiln. According to the efficient water-washing dechlorinating technology for the household waste incineration fly ash, quantitative water distribution is conducted before fly ash treatment, according to the chlorine contentof the fly ash, the water-ash ratio of the multi-stage counter-flow water washing can be accurately obtained; through continuous and stable feeding, the dechlorination effect is guaranteed, and unnecessary water resource waste and waste water treatment costs can be reduced; and, during multi-stage counter-flow water washing, after solid-liquid separation is conducted on the ash water of each stage, the filtrate is used as the washing water of the last stage of water washing, and therefore water resources are further saved.

Description

technical field [0001] The application relates to the field of fly ash treatment, in particular to a high-efficiency water-elution chlorine removal process and equipment for domestic waste incineration fly ash. Background technique [0002] With the rapid development of urbanization, the output of domestic waste in my country has increased year by year, from 189 million in 2013 to 206 million tons in 2015. The proportion of incineration disposal is increasing year by year. Fly ash is an inevitable product of waste incineration, accounting for about 3-5% of the amount of waste incinerated. According to this calculation, the fly ash produced by waste incineration nationwide will be 10,000-20,000 tons / day in the future. Such a large amount of fly ash is generated, making how to safely and effectively dispose of incineration fly ash has become an urgent environmental and social problem to be solved. [0003] Fly ash is the fine particulate matter collected in the flue gas puri...

AI Technical Summary

Problems solved by technology

The high concentration of chloride salts contained in fly ash will seriously limit the harmless disposal and resource utilization of fly ash

In order to remove the chlorine salt in fly ash to meet the requirements of co-processing in cement kilns, multi-stage countercurrent washing is usually used, such as three-stage countercurrent washing. The conventional three-stage countercurrent washing process is only suitable for fly ash with relatively low chloride ion content. Chlorine removal, if faced with fly ash with high chloride ion content, in order to reduce the chloride ion content in fly ash to meet the requirements of cement kiln co-processing, without changing the existing equipment, we can only increase the water used for the last stage of washing amount, which will lead to a large amount of water washing eluent entering the evaporation and crystallization step, so that the energy consumption of evaporation and crystallization to form clear water reuse will be greatly increased

If the existing equipment is changed, the number of water washing stages needs to be increased, and the equipment and process need to be adjusted, which makes the operation more difficult

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