Low-cost and high-efficiency supercritical spray drying method and equipment for slurry

Abstract

The invention relates to a size drying and separating method, in particular to a low-cost high-efficiency supercritical fluid spray drying method and device for size.According to the method, the size to be dried is heated and pressurized to the super-critical state of an adopted solvent, then atomization is conducted in a spray drying tower to achieve gas-solid separation quickly, powder is separated from solvent vapor through multi-stage recovery, and the solvent vapor is recovered through condensation.The large-scale production capacity of high-pressure spray drying and the product dispersion easiness of supercritical drying are combined to meet the requirement for drying of different kinds of size, and the solvent content of the size to be processed can be over 95%; due to the fact that the liquid size is only heated to supercritical temperature and pressure, heat conduction speed is high, indirect heating conducted through a drying medium is not adopted, heat efficiency is high, and the method and device are suitable for large-scale production; furthermore, due to the fact the heating process is conducted in an airtight mode in the absence of heating medium air, no combustion explosion risk exists, and the requirement for drying of flammable and combustible organic materials is met.

Description

technical field [0001] The invention relates to a slurry drying and separation method, in particular to a low-cost and high-efficiency supercritical spray drying method and equipment for slurry. Background technique [0002] Most drying processes use a medium to dry materials. The common medium is hot air. If the material to be dried contains organic solvents, the mixture of air and flammable organic solvents may catch fire, burn and explode. Therefore, vacuum drying or inert gas circulation drying is a commonly used process in this case. There is no convective heat conduction of gas in a vacuum state, and the heating efficiency is low. Although the boiling point of the liquid can be lowered, the heat transfer speed is a lawful process of drying, so the overall drying speed is still very slow. Through nitrogen, CO 2 , argon and other inert gas circulation heating and drying and solvent recovery, since the inert gas needs to be heated by a heat source, it is indirect heating...

AI Technical Summary

Problems solved by technology

These high-viscosity slurries are not suitable for drying by traditional methods, because the nano-powders will form agglomerated particles and blocks that are difficult to disperse. The current production efficiency of supercritical drying is low, and it is not suitable for large-scale production. For heating, the thermal efficiency is low, the equipment is complicated and the cost is high

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