Sas Preparation Of Ultrafine Particles Experimental Device And Nozzle Development,

In this paper, the researching status and technical characteristic of producing microparticles using Supercritical Fluids(SCF) precipitation are summarized and analyzed. As a new cross-technique referring to several subjects, the theory and practice of producing microparticles using SCF precipitation is now being researched and developped without usage in large scale. The corresponding equipment developed in recent years cannot satisfy the experimental request, and produce particles much more than nano-class, besides it is inconvenient to operate. By seriously analyzing and researching, we make much contribution to the design of equipment and nozzles. Several following aspects are mainly included in this paper:1. The equipment of producing microparticle using SCF precipitation have been designed, manufactured, and put into practice. This equipment have more advantages than others: the water-bath used in heating system, which can keep the temperature around nozzle stable, and intelligent conditioner used in control system, which control the temperature with accuracy. And both of that ensure the equipment reaching the request of technics.2.The nozzle, key part of the equipment, was researched and designed. Three new kinds of nozzles have been designed. Two of which are airflow nozzles with loop gap including internal-mixed and external-mixed mode. The outlet of the nozzle is an adjustable loop gap, which increase operational quantity of materiel and is not ready to jam. The external mixed nozzle has been manufactured and put into practice. Both of the nozzles have been applied for patents. The other kind of nozzle is swirl-pressure nozzle, which can make the fluid swirl and spray with high speed by the energy of itself after entering swirling chamber from tangent entrance. A very good result of spraying should be expected.3. A series of experiments have been carried out to test the heating system and the temperature controlling system of the equipment. The results showed that the heating system could keep the temperature around nozzle stable and keep the nozzle working in order. The temperature controllingsystem can adjust temperature according to preseted temperature in time and keep the temperature of the crystallization kettle in an anticipative range.4. the acetone-hydroquinone solution was used to test the capability of the equipment for producing microparticles. The results showed that the equipment could produce particles about 100nm in diameters, which is a great progress compared to other equipment.