Fine particle preparation device using supercritical fluid quick expansion

Abstract

Disclosed is an apparatus for preparing fine particles through rapid expansion of supercritical fluids, which is composed of a CO2 solvent bottle, a condensation compressor, a solvent storage tank, a high pressure pump, an extraction kettle, a nozzle, a crystallization kettle, an exhaust and collection device and a plurality of regulating and controlling valves. The apparatus adopts the connection and operation according to the following process: a CO2 solvent enters the condensation compressor from the CO2 solvent bottle by passing through a switch valve V1 and then is output to the solvent storage tank after being cooled, then is output to the high pressure pump for compression and then output to the extraction kettle through a regulating valve V2 to extract (or dissolve) materials in a material container of the extraction kettle, thereby forming a supercritical fluid which is then sprayed into the crystallization kettle via the nozzle by passing through a nozzle control valve V3, the solute in the fluid is separated out in the form of ultrafine particles after decompression expansion, and the solvent is discharged to the air via the exhaust and collection device by passing through an exhaust control valve V5. The apparatus overcomes a plurality of defects of the existing decompression expansion device, and can properly meet the requirements on process quality of the rapid expansion of supercritical solutions (RESS).

Description

technical field [0001] The invention relates to a device for preparing fine particles through a supercritical fluid rapid expansion process. Background technique [0002] Rapid Expansion of Supercritical Solution (RESS for short). That is, a supercritical fluid with a solute dissolved at a certain temperature and a certain pressure, usually carbon dioxide, after rapid expansion and decompression through a special nozzle, the solubility of the solute decreases rapidly and precipitates in the form of particles, fibers and film crystals. The shape, size and distribution of the precipitate mainly depend on the temperature before and after expansion, the pressure drop (the general pressure of supercritical fluid is between 20Mpa and 40Mpa, after the nozzle is sprayed out, it expands rapidly and decompresses, and reduces to near normal pressure), the flow rate of carbon dioxide , nozzle shape and other factors. [0003] In recent years, with the development of supercritical flui...

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Problems solved by technology

At present, the existing devices for the rapid expansion of supercritical fluid to prepare fine particles need to directly dissolve the extract as a solute in supercritical fluid to form a supercritical solution, and then expand it through a nozzle to form an ultrafine powder product. The materials for preparing ultra-fine powder products are limited, and there are many defects in the decompression expansion equipment, such as unstable pressure of the decompression precipitation device, uneven particle size of the ejected matter, poor drying effect, lack of effective exhaust filtration equipment, The mixed gas discharged from the exhaust port contains residual materials, etc., which cannot meet the process quality requirements of the supercritical solution rapid expansion process (RESS)

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