Abstract: By comparing several filter elements of different materials and structures, the filter elements of some equipment in polypropylene plant are upgraded. The non-metallic fiber PP felt which is easy to be blocked and ablated is upgraded to a strong and corrosion-resistant sintered metal fiber; and the disposable nylon filter element which is easy to be damaged is upgraded to a removable, cleanable and reusable metal filter. In order to separate oil and gas thoroughly, metal filter is used instead of wool in the oil and gas separator of the ice machine. After the revamp, not only the filtration and separation efficiency of the equipment is improved, but also the purchasing cost is saved greatly and long-term operation of the device is guaranteed.