Patent ID: 7662865

Claim:
A process for the synthesis of hydrocarbons based on a synthesis gas type feedstock, said process comprising: bringing said synthesis gas into contact with a catalyst in a reactor under Fischer-Tropsch conditions and controlling the partial pressure of water in said reactor keep the partial pressure of water below a critical value ppH 2 O- limit defined by the formula: pp H 2 O limit= exp(−7751/ d p .T ). P s ( T ) where T is the reaction temperature in K, d p is the average diameter of the catalyst pores in nm, determined by nitrogen adsorption-desorption (BJH method), and P s (T) is the saturating water vapour pressure at temperature T, in bar; wherein said partial pressure of water is controlled by implementing the following actions: a) determining the value ppH 2 O limit under the reaction conditions, taking into account the temperature of the reaction zone and the average pore diameter of the catalyst used in the Fischer-Tropsch synthesis stage; b) measuring the partial pressure of water vapor, comparing the measured partial pressure of water vapor with the value ppH 2 O limit , and making any necessary adjustment of said partial pressure in the Fischer-Tropsch synthesis reactor (ppH 2 O react ) by using at least one means selected from the following means, to verify the condition ppH 2 O react <ppH 2 O limit : increasing the feedstock flow rate, increasing the rate of recycling of unconverted gas in the case where the reaction section or the reactor is equipped with means of recycling unconverted gas, reducing the operating temperature, reducing the total pressure, introducing an inert diluent into the feedstock of the Fischer-Tropsch reactor, and continuously eliminating all or part of the water formed by the reaction.