Method and equipment for resource utilization of dewatered sludge in sewage plant by supercritical treatment

Abstract

The invention discloses a method and equipment for supercritical treatment and resource utilization of dewatered sludge of a sewage plant. The method is characterized in that: the dewatered sludge (the water content is 77 to 85 percent) is directly treated in a supercritical water vaporization mode, the flowability of the sludge is improved through a high-speed stirring device, blockage of a tubular reactor is prevented by adopting a high-pressure fluidized bed device, high heat of a gas-liquid separation process is fully utilized, and the low-temperature sludge is heated by using a heat exchanger; and the liquid phase product with high ammonia nitrogen content is directly recycled by a magnesium ammonium phosphate (MAP) method. The method has the advantages that: any moisture is not added in the vaporization process, and the sludge treatment efficiency is high; the heat can be utilized in the process; ammonia nitrogen in the liquid phase product is timely reclaimed so as to reduce secondary pollution; the reclaimed supernate can be recycled, the periodically discharged solid phase product with low heavy metal content can be directly used as a phosphate fertilizer, and the solid phase product with high heavy metal content can be used as an adsorbent; and the treatment expense of the whole system is reduced by resource utilization of the liquid phase product and the solid phaseproduct.

Description

technical field [0001] The invention relates to a method and equipment for resource utilization of dewatered sludge in a sewage plant by supercritical treatment, in particular to a method for direct supercritical water treatment of dewatered sludge (moisture content 77-85%) by using the characteristics of supercritical water Gasification treatment produces combustible gas containing a large amount of hydrogen; and then recovers the ammonia nitrogen in the liquid phase product. After recovery, the supernatant can be directly irrigated with surrounding green belts or surrounding landscape plant belts, and the solid product can be directly landfilled or treated with phosphate fertilizer The utility model can be utilized in various forms; the high cost of supercritical water gasification sludge can be reduced by recycling solid and liquid products, which belongs to the field of resources and environment. Background technique [0002] Sludge is an inevitable product in the proces...

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Problems solved by technology

[0004] The present invention proposes a method and equipment for resource utilization of dewatered sludge in a sewage plant through supercritical treatment. And the treatment products

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