Dynamic Analysis and Identification of a Wet Limestone Flue Gas Desulfurization Pilot Plant

In order to meet more stringent SO, regulations that have come into force recently, the operating conditions of wet limestone flue gas desulfurization (WLFGD) plants must be changed from design conditions to others where a higher SO2 removal is obtained; this results in higher operating costs. Furthermore. because of process disturbances. the SO2 removal target is usually set somewhat higher than necessary to provide a safety margin for meeting SO2 emission limits. Thus, the larger the safety margin, the higher the operating costs. How much larger the safety margin needs to be depends oil the proper tuning of the control strategy and dynamic properties of the WLFGD plant to be controlled. Both aspects can only be Studied if a dynamic model of the plant is available. However, dynamic modeling of WLFGD plants for control purposes has not been addressed in the literature so far. To deal with with this issue, in this paper we propose ail identification methodology for control purposes applicable to full-scale plants. The identification methodology is Put into practice in a WLFGD pilot plant, and the empirical dynamic model obtained is suitable for predicting the dynamic behavior of the pilot plant in a wide range of operating conditions. The dynamic behavior of the pilot plant is further analyzed from the perspective of the physical-chemical phenomena of the WLFGD process.