Abstract: To solve the problem of LPA (Large Particle Ash) plugging in the SCR de-NO_x equipment, the study on the technology of LPA interception is performed with the usage of the physical model based experiments. The effects of the hole pattern, the external structure and the mounting position of the LPA screen on its ash removal efficiency and the system drag force are analyzed. Multiple combination schemes of the dust hopper, the deflector and the LPA screen are compared for the best technical solution. The experimental results demonstrate that the ash removal efficiency of the LPA screen with rectangular opening is better than that with square or hexagonal opening. The drag force of the LPA screen varies inversely to the third power of the opening ratio. There is no obvious difference between the pleated and flat LPA screens in terms of the ash removal efficiency and the drag force. It is observed that the ash removal efficiency of the combination scheme of the deflector, the deep dust hopper and the low LPA screen is more than 95% when they are installed in the outlet of the economizer. The ash removal efficiency can be further improved when another dust hopper and a broken-line back wall are installed in the inlet of the vertical flue.