The Exploration On On-line Monitoring Of Real-time Distribution Of Solids In Solution Polymerization Vessel

Solution polymerization often has the participation of solid particles. For example, solid catalyst is added, solid phase by-products is producted and polyphosphazene microspheres is producted in the synthesis of polyphosphazene. Therefore, the real-time on-line monitoring of solid particle distribution is of great significance to the reaction process, endpoint judgment and precise control of the reaction.In this paper, A on-line, real-time monitoring system based on coulter principle is developed. The system is mainly composed of software system and hardware system.It proves that on-line and real-time monitoring system need warming process about 10 min to work stability and have good repeatability and test accuracy by background test,calibration and accuracy testing.The ODA is crystallized in the 2-Methoxyethanol solution with 10%water. In order to realize the detection of ODA crystals in this non-conductive system, two kinds of ODA crystallization process monitoring schemes are designed in this paper.Solid holdup in stirred tank is measured by Multisizer 4e particle counter,which indicated the Coulter counting method can be used to measure solid holdup. Because the density difference of solid-liquid two-phase is large, the on-line and real-time monitoring system fails to measure solid holdup. So the system need to be further improved.The experiments show that the monitoring apparatus designed in this paper can be used to continuously monitor the suspension state and the change of the solids holdup in the stirring process in real time. If the solid holdup is accurately detected, the structure of the instrument needs to be further optimized.