An external heat extractor for catalytic cracking with particle predistribution

Abstract

An external heat extractor for catalytic cracking in which particles can be pre-distributed, suitable for catalytic cracking units in oil refineries, characterized in that the external heat extractor (4) is internally equipped with multiple unit heat exchangers with separate water inlets and water outlets The tube (6), the heat exchange tube (6) extends from the top of the external heat extractor (4) to the bottom, and its bottom end is provided with a guide bracket (2) that limits the lateral swing of the heat exchange tube (6). The lower part of the heat exchange tube (6) is submerged in the dense-phase fluidized bed (11) at the bottom of the external heat extractor (4). The hot catalyst particles that come in from the catalyst inlet (10) in the middle part of the external heat extractor (4) first enter an annular fluidized bed (17), and utilize the predistribution of the annular fluidized bed (17) to the particles to make the hot particles flow from the The upper edge of the inner side wall (15) of the annular fluidized bed (17) or the overflow slot (19) provided on the inner side wall (15) evenly flows into the dense phase fluidized bed (11). In the dense-phase fluidized bed (11), the hot particles flow out from the catalyst outlet (1) at the bottom of the external heat extractor (4) after being cooled by contacting the side wall of the heat exchange tube (6). The fluidizing gas of the dense-phase fluidized bed (11) is introduced from the gas distributor (2) at the bottom, and after passing through the dense-phase fluidized bed (11), it is mixed with the fluidizing gas of the annular fluidized bed (17) and then combined The gas enters the dilute phase space of the regenerator of the catalytic cracking unit through the gas outlet (7) provided on the top of the external heat extractor (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. [0002] technical background [0003] 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. [0004] 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...

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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