Process for producing liquid and, optionally, gaseous products from gaseous reactants

A process for producing liquid and, optionally, gaseous hydrocarbon products from gaseous reactants, which process comprises

• feeding synthesis gas comprising mainly carbon monoxide and hydrogen as reactants, into a slurry bed of Fischer-Tropsch catalyst particles suspended in a suspension liquid;
• as the carbon monoxide and hydrogen pass upwardly through the slurry bed, allowing them to react at a temperature of at least 160.degree. C. and at a pressure of between 18 and 50 bar, to form liquid and, optionally, gaseous hydrocarbon products;
• separating liquid hydrocarbon products from the catalyst particles by passing, in a filtration zone within the slurry bed, liquid hydrocarbon products through a filtering medium in a first direction, so that a cake of solid catalyst particles forms on the filtering medium, while maintaining through the filtration zone a superficial gas velocity of between 5 and 70 cm/s, based on the filtration zone open cross-sectional area and while applying a pressure differential of up to 8 bar across the filtering medium and the cake;
• interrupting the passage of liquid hydrocarbon product through the filtering medium;
• backflushing the filtering medium by rapidly passing a flushing fluid through the filtering medium in a second direction, opposite to the first direction, for up to 30 seconds at a flushing fluid flow rate of at least 6000 l/h/m.sup.2 of filtering medium while maintaining a pressure differential of up to 10 bar across the filtering medium and any filter cake build-up thereon, thereby to dislodge the cake from the filtering medium;
• subjecting the filtering medium to a waiting period of between 15 and 60 minutes during which no filtering or backflushing therethrough takes place, to enhance removal of the filter cake as a result of turbulence within the slurry bed;
• and
• again passing liquid hydrocarbon product through the filtering medium in the first direction so that a cake of solid catalyst particles again forms on the filtering medium.