Abstract: In the second running period, larger differential pressure of reactor filter and fouling of the raw heat exchanger occurred in S Zorb unit in Gaoqiao Corporation. These problems brought great impact to the stable running of the S Zorb unit. The investigation discovered that the problems were occurred because of fouling of the filter and the heat exchanger. It is suggested that several methods can temporary be used to mild the problems, but the best way to reduce the pressure drop of the filter is to replace the filter cartridge and use new blow ball valves. While the fouling problem of the heater exchanger can be solved by thorough cleaning of bundle-tube of the heat exchanger and controlling the quality of FCC naphtha feed from tanks. These measures ensure a long period and stable running of the S Zorb unit.