A microchannel regenerator for supercritical hydrothermal synthesis of nanopowders

Abstract

The invention relates to a micro-channel heat regenerator for supercritical hydro-thermal synthesis of nano powder. The micro-channel heat regenerator comprises a flow dividing shell, a distribution header, a heat exchange base body and a bottom cover which are distributed from top to bottom, the flow dividing shell comprises five sleeves which are coaxially arranged, the radiuses of the five sleeves are sequentially increased, four first annular flow channels are formed between the adjacent sleeves, the innermost sleeve is internally provided with a second cold fluid straight-through flow channel, the second cold fluid straight-through flow channel penetrates through the axis of the distribution header, the axis of the heat exchange base body and the axis of the bottom cover, and four second annular flow channels and four first annular cavities are distributed in the distribution header around the second cold fluid straight-through flow channel; and a plurality of straight-through single flow channels and four second annular cavities are distributed in the heat exchange base body around the second cold fluid straight-through flow channel. The micro-channel heat regenerator solvesthe problems of rapid precursor heating, rapid reaction product cooling and agglomeration prevention of an SCHS technology, waste heat can be recycled, the heat exchange efficiency is improved, and agood foundation is laid for a supercritical hydrothermal synthesis technology from laboratory and pilot scale to large-scale batch production.

Description

technical field [0001] The invention relates to a regenerator in the technical fields of energy, chemical industry, environmental protection, synthetic materials, etc., and in particular to a microchannel regenerator for supercritical hydrothermal synthesis of nanopowder. Background technique [0002] Supercritical water (Supercritical Water, referred to as SCW) refers to a special form of water that has both gas and liquid properties when the temperature and pressure are higher than the critical state (T=374.15°C, P=22.12MPa). In this form, the dielectric constant in water is reduced and the density of hydrogen bonds is extremely low, with high diffusion rate and low viscosity and complete miscibility with many substances, which can change the reaction rate and chemical equilibrium. [0003] Supercritical hydrothermal synthesis (SCHS) refers to the rapid heating and heating of preheated water and low-temperature precursor solution (usually metal salt solution) in a specific...

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Problems solved by technology

[0005] At present, water jet coolers are mostly used in continuous supercritical hydrothermal synthesis systems, and a large amount of heat is lost. Even if some institutions use regenerators, there are certain technical problems in traditional casing or shell-and-tube coolers, including: (1 ) The utilization rate of the heat exchange area is low, the heat loss is large, the heat exchange efficiency is low, and the cycle efficiency is poor, which makes the system unable to achieve rapid heating and efficient mixing; Reunion, the quality of the produced product is poor; (3) The cooling time of the hot fluid is long, the temperature of the outlet product cannot be dropped rapidly, and reunion is easy to occur, causing problems such as blockage and deposition in the regenerator tube, affecting system stability

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