External catalytic cracking heater with pre-distributed particles

Abstract

The invention discloses an external catalytic cracking heater with pre-distributed particles and is suitable for a catalytic cracking device in an oil refinery. The external catalytic cracking heater is characterized in that a plurality of unit type heat exchange tubes (6) with independent water inlets and water outlets are arranged inside an external heater (4); the heat exchange tubes (6) extend from the top to the bottom of the external heater (4), and the bottom of the external heater is provided with a guide bracket (2) which limits transverse swing of the heat exchange tubes (6); the lower parts of the heat exchange tubes (6) are immersed in a dense-phase fluidized bed (11) at the bottom of the external heater (4); hot catalyst particles entering from a catalyst inlet (10) in the middle of the external heater (4) enter an annular fluidized bed (17), and the hot particles uniformly flow into the dense-phase fluidized bed (11) from the upper edge of a side wall (15) on the inner side of the annular fluidized bed (17) or an overflow notch (19) formed in the side wall (15) on the inner side by utilizing the particle pre-distribution function of the annular fluidized bed (17); the hot particles are contacted and cooled with the side wall of the heat exchange tubes (6) and flow out of a catalyst outlet (1) at the bottom of the external heater (4) in the dense-phase fluidized bed (11); and fluidized gas in the dense-phase fluidized bed (11) is introduced from a bottom gas distributor (2), and the fluidized gas which passes through the dense-phase fluidized bed (11) and the fluidized gas in the annular fluidized bed (17) are mixed to enter a dilute phase space of a catalytic cracking device regenerator through a gas outlet (7) formed on the top of the external heater (4).

Description

technical field [0001] The invention relates to an external heat extractor for catalytic cracking whose particles can be pre-distributed, and belongs to the technical field of petroleum processing. technical background [0002] Fluid catalytic cracking is one of the core production processes of light oil products in domestic oil refineries. It uses molecular sieve catalysts to crack low-value heavy raw materials (wax oil or residual oil) into high-value light oil products, such as gasoline , diesel and liquefied petroleum gas, etc. In China, the core position of fluidized catalytic cracking process is more prominent, it produces 70-80% of commercial gasoline, about 30% of commercial diesel and about 30% of propylene. [0003] A major feature of the catalytic cracking process is the system heat balance, that is, the heat required for the endothermic cracking reaction process is provided by the exothermic coke regeneration process. With the heavy and inferior quality of cata...

AI Technical Summary

Problems solved by technology

In general, although the above-mentioned patents can improve the reliability of the dense-phase descending external heat extractor to a certain extent, they cannot effectively improve the uneven heat extraction load of the heat exchange tubes in this type of external heat extractor. The problem of the reliability decline of the heat exchange tube cannot be completely solved, and the problem of particle erosion of the heat exchange tube

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