Fixed catalytic bed reactor with by-pass means through the bed

摘要

A device for circulating gas and/or liquid through a bed of solid particles comprises a means of deflection including a pipe whose upper end opens above the upper surface of the catalyst bed and a lower end opening below this surface, and a valve which opens when the differential pressure across the particle bed is greater than a preset value. The valve includes a means of varying the section of fluid flow in the valve automatically as a function of the fluid flow. The section of passage A of the valve and the fluid flow rate Q through the valve vary so that the ratio (A/A 0) x (Q/Q 0) is between 0.1 and 10, where A 0 and Q 0 are the section of passage and nominal flow of the valve. The valve also has a flared section of pipe with the smaller opening connected to one end of the deflection pipe and a movable piece mounted to displace between a closed and a maximum open position. The position of the movable piece is a function of the fluid flow in the flared section of pipe. Means of pushing displaces the movable piece towards the closed position where it obstructs the smaller end of the flared pipe. The means of pushing acts by gravity or uses a spring. The flared pipe is conical and the movable piece is a ball or conical section. Alternatively, the valve has at least one plate mounted to move about an axis on one end of the pipe to move between a closed and an open position, with means of pushing this place towards the closed position such as a rod extended beyond the plate, carrying a mass at its free end to act as a counterweight. The lower end of the deflection pipe opens under the particle bed, or in it with means of preventing the particles from entering the pipe. These means could be a cage with perforated walls enclosing the lower end of the pipe. The particle bed is surmounted by a distribution plate, comprising a plate above which the liquid accumulates and the upper end of the deflection pipe opens above or at the same level as this plate. A liquid and a gas circulate in backflow through a particle bed with such a deflection device. A number of particle beds operate together, with at least one bed being equipped with such a deflection device.