Supercritical water reactor which integrates material preheating, multi-stage enhanced degradation of pollutants and corrosion prevention into one

Abstract

The invention discloses a supercritical water reactor which integrates material preheating, multi-stage enhanced degradation of pollutants and corrosion prevention into one. An outer end cover and a split pressure-bearing wall of the reactor are connected through a sealing part and a connecting structure so as to achieve tight connection under supercritical pressure, wherein the end cover is disposed at the upper end of the split pressure-bearing wall, a coaxial nozzle abutment is arranged at the center of the bottom of the end cover, and a plurality of annular space of reactants are formed through exquisite cooperation of the end cover and the nozzle abutment. The reactor is provided with multiple stages of oxygen injection mouths and multiple stages of auxiliary fuel injection mouths soas to enhance the reaction process. The reactor is provided with an evaporation wall structure, and a subcritical / supercritical water film or a high-temperature gas film is formed inside the reactor through the evaporation wall, so that corrosion to the inner wall surface of the reactor is slowed down effectively, and the temperature of the reactor is maintained effectively. Through the reactor, heat exchange between organic waste and reaction products in the reactor can be achieved, exothermic heat of the reaction can be made full use of, and heat consumption can be reduced effectively in thepreheating process.

Description

technical field [0001] The invention belongs to the field of environmental protection and chemical engineering, and relates to the use of supercritical water as a reaction medium for the harmless treatment of high-concentration organic pollutants that are difficult to degrade biochemically, and in particular to a material preheating-pollutant multi-stage enhanced degradation- A multi-functional supercritical water reactor for corrosion prevention and control. Background technique [0002] Supercritical water refers to water in a special state whose temperature and pressure exceed its critical point (374.15°C, 22.1MPa). Its density is close to that of liquid, which is 100 to 1000 times larger than that of the corresponding atmospheric pressure gas; its viscosity is close to that of gas, which is about 1% to 10% of that of the corresponding liquid; its diffusion coefficient is between gas and liquid, which is 10 times that of ordinary liquid ~100 times. In the supercritical ...

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Problems solved by technology

At present, most of the heating methods of supercritical water oxidation equipment at home and abroad are in the form of electric heating, and the investment cost of high-temperature and high-pressure external preheating equipment is huge, which has caused a huge obstacle to the large-scale industrial application of SCWO technology.

[0006] (2) Chemical wastewater, industrial sludge and other refractory pollutants have complex components. Conventional SCWO treatment cannot achieve the discharge of the reaction effluent. It is often necessary to perform secondary treatment on the reaction effluent in subsequent processes, which greatly increases the complexity of the system. Further increase equipment investment costs and system operating costs

[0007] (3) Material corrosion problem

In addition, heteroatoms such as halogen, sulfur, and phosphorus contained in organic matter will produce acid after decomposition in supercritical water, which will further cause strong corrosion of equipment

[0008] (4) Supercritical water oxidation reaction conditions are harsh, requiring higher temperature and pressure

For conventional tubular reactors, the tube wall of the reactor needs to withstand a high temperature of 600°C and a high pressure above 25MPa, which leads to an increase in the cost of the reactor

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