Preparation method of modified evaporation wall for supercritical water oxidation reactor

Abstract

The present invention provides a method for preparing an evaporation wall for a supercritical water oxidation reactor, comprising the following steps: step 1, substituting the water film flow velocity on the inner surface of the evaporation wall of the reactor into formula I and formula II, and calculating the corresponding adhesion force γ lv w(θ adv ‑θ rec ); Step 2, cleaning the porous metal plate as the evaporation wall matrix; Step 3, putting the evaporation wall matrix into acid for acid etching; adjusting the reaction time of the acid etching reaction according to the theoretical value of the adhesion force obtained in the step 1 and reaction temperature; step 4, rinse the evaporating wall matrix after the acid etching reaction in step 3 with deionized water, and then put it into an oven for drying; step 5, place the evaporating wall matrix after cleaning and drying in step 4 in a high-temperature sintering furnace Carry out sintering in the middle, obtain the modified evaporation wall with micro-nano rough morphology on the surface; formula I is: ma=F=mg-γ lv w(θ adv ‑θ rec ) Formula II is: the present invention can maintain the integrity and stability of the water film on the inner surface of the evaporation wall, making the evaporation wall reactor more corrosion-resistant and prolonging its service life.

Description

technical field [0001] The invention relates to the technical field of supercritical water oxidation evaporation wall reactors, in particular to a preparation method of a modified evaporation wall for supercritical water oxidation reactors. Background technique [0002] Supercritical water oxidation (SCWO) technology is a high-efficiency, thorough treatment and deep oxidation of organic matter without secondary pollution proposed by Modell et al. in the mid-1980s. Under high temperature and high pressure (usually reaction temperature 400°C-600°C, reaction pressure 25MPa-40MPa), supercritical water is used as the medium, air, oxygen and other oxidants deeply oxidize and decompose organic matter, and are widely used in chemical industry, metallurgy, printing and dyeing, Industries such as paper making, medicine, petroleum and food. It has great application prospects in dealing with military poisonous materials such as chemical weapons, rocket solid fuel materials, explosive m...

AI Technical Summary

Problems solved by technology

[0004] The upper part of the supercritical water oxidation evaporation wall reactor is the main part of the oxidation reaction. It is in the intense chemical reaction area and the supercritical environment of high temperature and high pressure. The convective diffusion and mixing between the main fluid and the water film are extremely strong, making the upper part of the evaporation wall The continuity of the water film is destroyed; and the water film flows down instantly under the action of its own weight, and the integrity of the water film on the upper part of the evaporation wall is difficult to maintain, so that the upper part of the evaporation wall that is not protected by the water film is easily burned or corroded

[0005] In view of the above problems, in the existing processing methods, the patent application of Ma Chunyuan et al. (publication number CN101164912A) discloses a structure of "annular water inlet and water retaining ring", but the water film in each local partition is still uneven; Wang The patent application of Bing et al. (publication number CN 107385261A) prepared a porous evaporation wall with an average pore size of 2-10 μm and a porosity of 10%-35%, which is conducive to the formation of a complete water film, but cannot slow down the instantaneous flow of the water film. No significant improvement in maintaining water film integrity

The patent application of Xu Donghai et al. (publication number CN 109133317A) realizes the adjustment of the thickness of the water film by adjusting the evaporation intensity, the concentration of the organic raw material, the preheating temperature of the organic raw material, the inlet temperature of the evaporating water, and the water flow ratio of the evaporating wall of each branch. However, this method greatly increases the complexity and difficulty of reactor operation, and requires high-precision and high-sensitivity detection equipment that can withstand harsh conditions in the reactor, which is difficult to apply to industrial applications

In short, the existing methods for improving the evaporation wall are limited to water-retaining parts or adjusting process parameters, but the above-mentioned methods are not only very complicated in equipment and operation process, but also unable to change the incomplete and unstable state of the local water film, which is difficult to apply to industrial applications

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