Catalytic cracking process of petroleum hydrocarbons

Abstract

The present invention discloses a catalytic cracking process of petroleum hydrocarbons and a tube-in-tube riser reactor used therein. In the present invention, a catalyst is fed via an inlet conduit to an inner tube and an annular space between the inner and outer tubes of the tube-in-tube riser reactor to contact a hydrocarbon feedstock, and the hydrocarbon feedstock is cracked under FCC conditions, then a reaction stream thus produced flows into a separation apparatus via a confluence tube to separate a hydrocarbon product stream from a spent catalyst, the spent catalyst is stripped and regenerated, then a regenerated catalyst is recycled for reuse. The process of the present invention can improve both product distribution and product properties.

Description

TECHNIQUE FIELD[0001] The present invention relates to a catalytic cracking process of petroleum hydrocarbons ire the absence of hydrogenTECHNIQUE BACKGROUND[0002] Although catalytic cracking process has been developed for several decades and formed a relatively complete system of techniques, refiners are still studying and searching untiringly to seek for a process not only meeting the requirements of increasingly rigorous environmental laws and regulations but also according with the change of market demands so as to create satisfactory economic benefit for enterprises.[0003] U.S. Pat. No. 5,043,522 and U.S. Pat. No. 5,846,403 relate to the improvements of conventional catalytic cracking process, in which part of catalytic gasoline is fed to a riser reactor at upstream of the feedstock nozzles to contact a regenerated catalyst having high activity at a high temperature, so that the yields of light olefins such as propylene, butylene and the like are increased, meanwhile the octane...

AI Technical Summary

Benefits of technology

[0010] Another object of the present invention is to provide a relay cracking process of petroleum hydrocarbons, which can make the catalytic cracking process not only have a desirable ability to convert heavy oils and better product selectivity but also simplify flowchart and easy to operate.

[0022] The processes provided in the present invention are simple in equipment and flexible in operation. Not only the reactions of heavy oils and light oils can be carried out separately in their respective reaction zones, but also reaction conditions can be regulated flexibly according to physical-chemical properties and mass flow of different feedstocks, which thus create favorable conditions for improving product distribution and product quality.

[0023] The processes provided in the present invention can make flexible arrangements of several production schemes such as, for example, gasoline scheme, diesel oil scheme, liquefied petroleum gas scheme, light olefins scheme and the like. Therefore, petroleum refineries can adjust product distribution pattern in time by using the processes of the present invention in accordance with variation of market demand so as to obtain more profitably economic benefit.

[0024] The processes of the present invention can obviously improve catalytic cracking product distribution, reduce yields of dry Gas and coke, increase yields of high value products such as liquefied petroleum as, gasoline and / or diesel oil and the like.

[0025] Furthermore, the processes provided in the present invention can also improve the product quality and reduce the environmental pollution caused by petroleum products It is proved by test that the processes can decrease olefin content of gasoline and increase the octane number of gasoline, reduce freezing point of diesel oil., improve sensibility of the diesel oil to flow improvers, increase stability of the diesel oil; meanwhile, the processes have a certain effect in reducing contents of the impurities such as sulfur, nitrogen and the like in gasoline and diesel oils.

Problems solved by technology

Although catalytic cracking process has been developed for several decades and formed a relatively complete system of techniques, refiners are still studying and searching untiringly to seek for a process not only meeting the requirements of increasingly rigorous environmental laws and regulations but also according with the change of market demands so as to create satisfactory economic benefit for enterprises.

The first category of the processes need a little modification on equipment, however, reaction conditions of light oils are basically fixed, and product distribution and product properties can hardly be improved by means of optimization of operation variables.

However, for the second category of the processes, costs in both construction of unit and reconstruction of equipment are increased significantly.

Furthermore, in practical industrial production, a complicated flowchart will greatly increase the difficulty in operation.

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