At a 630 MW thermal power facility in Mugla, Turkey, the implementation of wet flue gas desulfurization (WFGD) systems introduced concerns related to stack liquid discharge (SLD). With three units operating under similar conditions, the plant required a scalable, reliable solution to mitigate SLD and ensure long-term system performance.

Verdantas Flow Labs (formerly Alden Research Laboratory) was brought in to investigate and resolve the issue. Our team began by developing a scaled physical flow model of the absorber outlet ducting and stack liner. This model, built at a 1:17.49 scale, allowed us to simulate gas and liquid flow behavior under a range of operating conditions, including worst-case scenarios for condensation and droplet carryover.

Using a combination of proprietary condensation modeling and hands-on physical testing, we identified the primary sources of liquid within the system. These included thermal condensation due to gas cooling, adiabatic condensation from pressure changes, and direct droplet carryover from the absorber. Our analysis showed that under the coldest ambient conditions, the system could generate nearly 10 liters of liquid per minute—enough to pose a serious risk of SLD if not properly managed.

To address this, we designed a comprehensive liquid collection system tailored to the plant’s geometry and flow dynamics. The solution included 18 custom-engineered liquid collectors and five external drains, each strategically placed to intercept and redirect liquid away from the gas stream. These components were fabricated from corrosion-resistant materials such as C276 and FRP, and were designed to withstand the harsh, acidic environment inside the ducts and stack.

Following implementation, system performance was evaluated under full-load conditions. Pressure loss across the system decreased from 127.9 mm H₂O to 121.2 mm H₂O at maximum load, indicating more efficient flow through the duct and stack. At the stack exit, gas flow met EPA Method 1 standards for cyclonic behavior, with a resultant angle of just 12.5° and a standard deviation of 5.3%. Most importantly, no re-entrainment of liquid was observed at either minimum or maximum operating conditions.