| There are three methods in the production of alumina, which are the sinter, Bayer and combined method. Owing to the low-grade A/S of the aluminum mine, the sinter and combined method are widely adopted in our country. In the procedure of the sinering, the function of dissolving predure is to make the Al2O3 and Na2O dissolved from the clinker fired by rolling kiln as much as possible. The alumina dissolving procedure is the bond of the two producing process of wet and dry method, it is also the most important part of economic norms in the sinter method. It is of comprehensive and complicated characteristics of nonlinearity, large time-delay, slow time-varying and so many key engineering parameters which can not be detected online. It is dramatically significant and difficult to study the control and the optimization algorithms, how to establish the control system of alumina dissolving process is an issue which has greatly practical value. Supported by National High-Tech Research and Development Program 863, the control system of dissolving process is designed and developed.The content of this paper are summarized as followed:(1) Combining the characteristics and the control requirements of the dissolving process, the two-layer architecture of computer control system for alumina dissolving process is researched and developed, including PMS(process monitoring system) and PCS(process control system), and the system's functions and hardware are designed. The computer network includes two layers as industry Ethernet and device network. Information integration and function integration of computer control system is achieved., the optimization control system is designed and developed in the layer of the process control system, the dissolving key targets are guaranteed through on-line adjusting the setting point of base control loop which is belonged to the bottom layer.(2) The control strategy for alumina dissolving process is researched; the intelligent optimization control strategy based on expert reasoning method is proposed which is designed for the sodium aluminate dissolving key targets. The adjusting method based on golden section for PID parameters of the base control loop and process loop control and device logic interlock control strategy are reasearched. The process loop mainly includes the feed-in aluminum clinker control loop, the red mud adjusting fluid flow control loop and the carbon adjusting fluid flow control loop. The optimization control strategy is proposed for the dissolving control loop, the controlled object is built on the basis of experience data, based on the golden section method to select the controller parameters, and some simulations have been done in accordance with the controller parameters, besides, the grinding mill's fault diagnosis alarming strategy for workload is also discussed.(3) Based on the the above-mentioned strategy and the background of Shanxi aluminum dissolving project, the dissolving control system is designed and developed which is based on the Honeywell PKS series DCS. The main work includes the workmanship flow chart configuration, environment configuration, history configuration, alarming configuration, table printing and so on. The local and remote control method of the oil station, grinding mill, grader, wide cart, strap balance and dissolving pump. The interlock program is developed for the machine which has the interlock relationship. Another work is developing the control loops of the two adjusting fluid, at the same time, for the sake of eliminating the interference signals, the filtering program is developed. |
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