the powder separation unit comprising a driving motor, counter-rotating rollers, rollers, a powder accumulation bin, a catalyst powder outlet, and a shell, the counter-rotating rollers and the rollers being configured inside the shell, the driving motor driving the counter-rotating rollers to operate, the counter-rotating rollers and the rollers being configured at intervals, one end of the powder accumulation bin being connected with the shell, and the other end of the powder accumulation bin being connected with the catalyst powder outlet;

the powder recovery unit comprising an induced draft fan, a powder recovery inlet, a cyclone outlet, a primary filter, a movable sealing sheet, a secondary filter, a cyclone passage and a recovery shell, the induced draft fan being connected to an induced draft fan interface, the powder recovery inlet being configured on an outer side wall of the recovery shell, the cyclone outlet being configured on an inner side wall of the recovery shell, and the cyclone passage being configured between the powder recovery inlet and the cyclone outlet; the primary filter and the secondary filter being sequentially configured on the inner side wall of the recovery shell from bottom to top, the secondary filter having a same cross-sectional size as the recovery shell, an opening being configured in a middle position of the primary filter, and the primary filter forming a conical surface with the diameter larger at a top and the diameter smaller at a bottom; and

the catalyst powder outlet being connected with the powder recovery inlet.