APPARATUS AND PROCESS FOR CONTROLLING TEMPERATURE OF HEATED FEED DIRECTED TO A FLASH DRUM WHOSE OVERHEAD PROVIDES FEED FOR CRACKING

摘要

An apparatus and process are provided for cracking hydrocarbonaceous feed,wherein the temperature of heated effluent directed to a vapor/liquidseparator, e.g., flash drum, whose overhead is subsequently cracked, can becontrolled within a range sufficient so the heated effluent is partiallyliquid, such as from about 260 to about 540~C (500 to 1000~F). This permitsprocessing of a variety of feeds containing resid with greatly differingvolatilities, e.g., atmospheric resid and crude at higher temperature anddirty liquid condensates, at lower temperatures. The temperature can belowered as needed by (i) providing one or more additional downstream feedinlets to a convection section, (ii) increasing the ratio of water/steammixture added to the hydrocarbonaceous feed, (iii) using a high pressureboiler feed water economizer to remove heat; (iv) heating high pressure steamto remove heat, (v) bypassing an intermediate portion of the convectionsection used, e.g., preheat rows of tube banks, and/or (vi) reducing excessoxygen content of the flue gas providing convection heat.