Abstract: A process for producing liquid and/or gaseous products from gaseous reactants includes feeding them, at a low level, into a slurry bed of particles suspended in a liquid, to react as they rise therethrough to form the products, with the reactants and any gaseous product assisting in maintaining the suspension. The liquid product forms, together with the suspension liquid, the liquid phase of the bed. Any gaseous product and unreacted reactants rise from the bed into a head space. Slurry passes downwardly in the bed through downcomers located respectively in first and second downcomer regions of the bed, thereby redistributing solid particles within the bed. The second downcomer region is spaced vertically with respect to the first downcomer region. Any gaseous product and unreacted reactants are withdrawn from the head space and liquid phase is withdrawn from the bed.