Device for mixing and distributing a dense fluid and a light fluid above a granular bed and its use for downflow discharge

摘要

A device has a tubular system for supplying dense fluid from outside the reactor into a volume between the plate and the level of at least one of the side orifices of the chimneys in contact with the dense fluid. The tubular system has outlet vents for the dense fluid which are completely immersed in the volume above the plate. A horizontal plate (62) covers the whole section of the reactor and supports a number of vertical chimneys (60) whose upper and lower ends communicate with the parts of the reactor above and below the plate respectively. The chimneys are pierced with side holes (63) allowing the dense fluid and part of the light fluid to flow into the chimneys. The tubular system is at a level near that of the plate. There are between 100 and 700 chimneys per m2 of reactor section, preferably between 150 and 500 per m2. The side holes are spread over the length of the chimneys at a number of levels, with the lowest level 100-300 mm above the outlet from the tubular system and the levels at least 20 mm apart. The chimneys extend above the plate for a distance h between 10-100 mm and the lower end of the chimneys are at a distance d from the top of the bed immediately under where d is between 0-50 mm, 0 mm excluded, preferably 0-20 mm, 0 excluded. The tubular system has a main vertical tube (50) and a multiplicity of horizontal secondary tubes (51) with outlet orifices. The main vertical tube has side vents at its bottom end (53) at a distance of 100-500 mm from the lowest chimney side hole. The outlet orifices from the secondary tubes point downwards to form an angle of -90 degrees to +90 degrees with the vertical, preferably -45 degrees to +45 degrees. These orifices are in the form of nozzles of constant or variable section. The chimney side holes are more than 2 mm diameter and less than 75% of the chimney diameter. The device also includes a gas/liquid separator in the head of the reactor before the fluids are introduced into the mixture. The separator is cylindrical and includes means of rotation and separation, with 1-4 tangential outlets for the liquid and gas. The ratio of the total area of the gas outlets to the section of the cylinder is equal to 2. The tangential outlets for the gas and liquid are separated by at least 50 mm and preferably 100-300 mm. The cylinder contains a helix with between 1-6 turns, preferably between 2 and 3 turns.