Sludge hydrothermal oxidization reaction system and method with function of product reflux pretreatment

Abstract

The invention discloses a sludge hydrothermal oxidization reaction system and method with a function of product reflux pretreatment, and belongs to the field of municipal sludge treatment. A gaseous product generated through hydrothermal oxidation is led out from the top of a reactor, residual oxygen and produced carbon dioxide after the reaction are removed, and then the gaseous product is introduced into a sludge pretreatment tank and directly contacted with sludge for preheating the sludge; a divided flow part of a liquid product flows back to the sludge pretreatment tank; steam and hot water preheat sludge under the stirring action, and the problem that heat recovered by the system is not enough to preheat the sludge to reach the feeding temperature is solved; the residual liquid product is treated with a vacuum flashing method, flash steam is recovered and sent to a pretreatment sludge feeding pipe for tracing heat, and meanwhile, a liquid phase after flash deoxidization enters a downstream heat-exchange device for waste heat recovery. With the adoption of measures, high-temperature material heat of the system can be recovered to preheat sludge, corrosion of dissolved oxygen to a heat exchanger can be relieved, system investment is reduced, and energy utilization rate and economic efficiency of the system are increased.

Description

technical field [0001] The invention belongs to the field of municipal sludge treatment, in particular to the treatment of sludge produced by sewage treatment plants. Background technique [0002] Municipal sludge is a solid-liquid mixed flocculent substance composed of various microorganisms and organic and inorganic particles. It mainly comes from the urban sewage purification process and is a by-product of urban sewage treatment plants; the basic process of a typical urban sewage plant Process such as figure 1 Shown: Urban sewage enters the sewage treatment plant through the urban drainage system. After passing through the grille and the grit chamber, the larger suspended solids or floating solids and inorganic particles with larger specific gravity (such as silt, cinder, etc.) in the sewage are removed. ; Then the sewage enters the primary settling tank, and the settleable substances contained in the sewage settle down to form the primary sludge; the sewage continues to...

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Problems solved by technology

[0011] The purpose of the present invention is to solve the problem of insufficient heat in the sludge pretreatment recovery system in the prior art, the need to increase heating equipment to increase investment and system complexity, and the dissolved oxygen of the liquid phase product after the reaction corrodes the equipment at high temperature, etc.

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