在反应器I中，浸渍有硝酸钴溶液的催化剂载体在400℃至450℃之间的煅烧温度下被氧化，以产生包含氧化钴的催化剂前体。 该还原反应器A中的催化剂前体与富含氢的还原性气体接触，并且通过使还原气体流循环，从而将钴氧化物还原成Co并产生水。 在反应器A出口处回收的水中，含水量降低到装载有还原气体的废气流量的200ppm，还原气体的至少一部分再循环到反应器A.在此过程中，还原气体 在反应器A中的水含量维持在低于10,000ppmvol。

The method enables preparation of a catalyst to be used in a Fischer-Tropsch reaction. Is oxidized in a reactor I impregnated catalyst support with a cobalt nitrate solution to a calcination temperature between 400 ° C and 450 ° C to produce a catalyst precursor comprising cobalt oxides. Then, the catalyst precursor is brought into contact in the reduction reactor A with rich reducing gas in hydrogen and low in water by circulating the reducing gas flows, so as to reduce the cobalt oxides to Co and produce the 'water. Then reduced the water content to 200 ppmvol the flow of reducing gas loaded with water recovered at the outlet of the reactor A. And, recycling at least part of the flow of reducing gas into the reactor A. In the method, maintains the reducing gas to a moisture content of less than 10 000 ppmvol in the reactor A.