Sludge treatment and recycling method

Abstract

The invention particularly relates to a sludge treatment and recycling method. The method comprises the following steps: sludge conditioning, sludge deep dewater, crushing and granulation, sludge drying, and sludge pyrolysis carbonization reaction. By using an iron salt as the main conditioner, deep dewatering is carried out on the sludge to lower the water content from 90% or above to 60% or below, thereby reducing the heat source required by the subsequent drying. The sludge drying adopts the heat energy released by combustion of combustible gas generated by the subsequent carbonization technique, thereby lowering the water content of the sludge to 20% or so on the premise of basically not adding any external energy source. Since the iron salt is added in the sludge conditioning stage, when the dried sludge is subjected to anoxic / anoxic pyrolysis reaction in the carbonization furnace, the iron oxides can be supported onto sludge-base activated carbon, thereby preparing the environment-friendly material with wide applicability. Therefore, the method implements harmless and recycling treatment on the sludge at lower cost, can treat waste with waste, produces the product with higher economic added value, and thus, has higher economic and social values.

Description

Technical field [0001] The invention relates to the technical field of sludge treatment, and more specifically to a method for sludge treatment and resource utilization. Background technique [0002] Deep sludge dehydration technology has the advantages of low investment and operating costs. It is currently widely used worldwide. However, due to the large amount of conditioners and the large increase in dry sludge basis, subsequent disposal can only be landfilled, and resource utilization methods Restricted; simply using the drying-heat treatment (incineration / pyrolysis / carbonization) of sludge can minimize the volume and reduce the volume, achieve harmlessness and stabilization, but the operating cost is high. In general, the product quality Generally not high, so the added value is low, the outlet is limited, and the economy is poor; the deep sludge dehydration technology can effectively reduce the moisture content of the sludge and reduce the amount of sludge transported out o...

AI Technical Summary

Problems solved by technology

[0002] Sludge deep dewatering technology has the advantages of low investment and operating costs, and is currently widely used in the world. However, due to the large amount of conditioning agent and the large increase in sludge dry basis, it can only be landfilled for subsequent disposal. Resource utilization Restricted; simply using sludge drying-heat treatment (incineration / pyrolysis / carbonization) can reduce volume and volume to the greatest extent, achieve harmlessness and stability, but the operating cost is high. It is generally not high, so the added value is low, the outlet is limited, and the economy is poor; the deep dehydration technology of sludge can effectively reduce the moisture content of sludge and reduce the amount of sludge transported abroad. It is widely used in my country, but generally a large amount of Iron salts (such as: ferric chloride or polyferric sulfate, etc.), the increase in sludge dry basis is large, and it also limits the subsequent terminal disposal methods

[0003] At present, the sludge drying-heat treatment (incineration, carbonization) process route can completely decompose the organic matter in the sludge and solidify toxic and harmful substances such as heavy metals at the same time, but due to the high water content of the feed sludge, the energy generated by heat treatment It is not enough to provide the heat source required for front-end drying, so it is often necessary to add additional energy such as oil, natural gas or coal, so that the dried sludge can reduce the moisture content to the lower range required for heat treatment feed, so for The operation and maintenance requirements of the equipment are high, the operation cost is high, and there is a risk of tail gas pollution such as dioxin; the sludge pyrolysis / carbonization technology decomposes the organic matter in the sludge into combustible gas under the condition of anaerobic or anoxic , liquid oil and solid carbon, less exhaust gas, low risk of dioxin generation, wide range of products, can be used as dehydration aids, snow melting agents, soil improvers, fuels, adsorbents, etc.

However, the product quality is low and the added value is not high, which limits its promotion and application

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