<p>One of the key challenges for sustainable cement production is the development of plastic waste co-processing technology. When plastic waste is utilized as alternative fuels, the chlorine concentration in pyroprocessing increases with the fuel substitution rate, resulting in flow path blockage and localized corrosion. Chlorine bypass (CBP) systems have been applied as a control technology for such chloride deposition issues; however, design optimization studies are still required to ensure efficient system operation. Accordingly, this study aimed to determine the optimal probe installation position that satisfies the required bypass ratio under fuel substitution rates exceeding 80%, using computational fluid dynamics (CFD) analysis. Analysis of kiln gas flow fields and dust particle behavior showed that the probe installation position caused noticeable differences in pressure loss, cooling performance, and the particle size distribution of bypassed dust. In the center installation, only fine particles smaller than 16 µm were carried into the bypass stream. In contrast, the right and left installations allowed coarse particles larger than 20 µm to represent approximately 54% and 56% of the total bypassed mass flow rate, respectively. These results indicate that the center installation more effectively promotes chlorine removal by selectively capturing fine particles. The findings of this study provide useful design and operational guidelines for chlorine bypass probes in cement pyroprocessing</p>