A NEW ZONE-MELTING PROCESS BASED ON CONTROL OF DISTRIBUTED PARAMETER SYSTEM

Recently, chemical process operations are becoming more precise, making process control more difficult by conventional dynamics and control theories alone. The zone melting process considered in this work is a typical example of advanced chemical processes and requires highly precise operations. A precise temperature profile must be achieved and maintained against strong disturbances due to the movement of a sample tube or heaters and to interactions between heaters. To overcome this difficult problem, a new zone melting process is proposed in this paper. Without movement of either sample tube or heaters, realization of, the desired time-varying temperature profile is attempted by manipulation of fixed heaters. The process dynamics are treated as a distributed-parameter system. Applying distributed parameter control to the zone melting process in a simulation, stimulation verified that the process could be realized. Moreover, experimental results using an anthracene zone melting apparatus also showed good control performance.