Long-term scouring by dust-laden airflow in industrial dust removal pipelines causes inner wall wear, leakage, and excessively high pressure drop that increases fan energy consumption. Since existing studies lack quantitative analysis on multi-parameter interactions of Z-type elbows, this study aims to provide a theoretical basis for their wear-resistant and energy-saving design. For Z-type combined elbows in ventilation and dust removal systems, this work adopted a bidirectional coupling method of computational fluid dynamics (CFD) and discrete phase model (DPM) combined with response surface methodology (RSM), established a gas-solid two-phase flow model, used a turbulent model to simulate the gas flow field and Oka erosion model to calculate wall erosion rate (validated with good simulation-experiment consistency). Five parameters (bend-radius-to-diameter ratio, inlet velocity, particle mass flow rate, particle size, and connection-length-to-pipe-diameter ratio) were systematically analyzed for their effects on pipeline erosion and pressure drop. A multi-objective optimization yielded the optimal parameter combination. The results showed that the minimum erosion occurred at a bend-radius-to-diameter ratio of 2~3, while low erosion was observed when the connection-length-to-pipe-diameter ratio was 2~3. Inlet velocity significantly increased both erosion and pressure drop, with the pressure drop tripling at 32 m/s. Erosion and pressure drop increased with particle mass flow rate. Erosion peaked at a particle size of 150 μm, whereas particle size did not influence pressure drop. The first elbow exhibited higher average wear with a wide distribution of erosion, while the second elbow experienced concentrated wear. The optimal combination (connection length ratio of 2.7, bend-radius-to-diameter ratio of 3.6, inlet velocity of 20 m/s, particle mass flow rate of 6×10-5 kg/s, particle size of 208 μm) realized coordinated optimization of low erosion and pressure drop. Findings provide quantitative references for pipeline design/protection and are practically valuable for reducing maintenance costs and system energy consumption.