Apparatus and process for separating fine solid particulates from a gas stream

Claim 1

A fluidized catalytic cracking process for cracking a heavy hydrocarbon feed, the process comprising: a) contacting the heavy hydrocarbon feed with a cracking catalyst to produce a light hydrocarbon product and a spent catalyst having coke deposited thereon; b) regenerating the spent catalyst in a catalyst regenerator by contacting the spent catalyst with air to burn the coke and provide a regenerated catalyst and a flue gas; c) separating the regenerated catalyst from the flue gas using a first stage and a second stage separator located within the catalyst regenerator to yield a catalyst fines-contaminated flue gas stream; d) recycling the regenerated catalyst to the cracking reactor for further production of the light hydrocarbon product; and e) purifying the catalyst fines-contaminated flue gas stream in a third stage separator apparatus having an upper and a lower tube sheet contained therein and a plurality of cyclones between the upper and lower tube sheets, each cyclone comprising: i) a substantially vertical cyclone body having a closed bottom end and a top end fixed with respect to the upper tube sheet, the cyclone body defining a gas inlet at its top end for receiving a portion of the catalyst fines-contaminated flue gas stream from above the upper tube sheet and a sidewall of the cyclone body defining a plurality of discharge openings between the upper and the lower tube sheets for tangentially discharging particles and a minor amount of an underflow gas stream; ii) one or more swirl vanes located proximate the gas inlet to induce centripetal acceleration of the catalyst fines-contaminated flue gas stream; and iii) a gas outlet tube located centrally within the cyclone body, extending through the closed bottom, and further extending through the lower tube sheet, the gas outlet tube defining a clean gas inlet for receiving a purified gas stream from within the cyclone body and further defining a clean gas outlet located below the lower tube sheet for discharging the purified gas stream.