Process for controlling the water balance of wet flue gas desulfurisation plants

摘要

The water balance of wet flue gas desulphurisation plants, especially of two-stage plants with limestone as the absorbent and gypsum as the end product, is controlled via the level in the bottom and the rate of the process water fed via the washing of the demisters, a) the level in the bottom being measured at the three points max, min 1 and min 2, b) the washing of the demisters being carried out in variable cycles with fixed spraying times but variable spraying pauses, c) the purging of suspension from the bottom for separating off solids and recycling of the liquid being controlled in normal operation only via the density of the suspension in the bottom in the region of the measuring points min 1 and min 2 and only in the case of an emergency, when the measuring point max is exceeded, independently of the density of the suspension.