Abstract Coke deposition rate in the reactor of a fluid cat cracker is controlled by varying the severity and conversion level in the reactor, while maintaining maximum air rate to the regenerator. The temperature at the outlet of the regenerator, which is an indication of afterburning and amount of coke buildup, is used to control reactor temperature and catalyst-to-oil ratio in the reactor (by resetting the reactor temperature recorder control, which in turn controls the flow of hot regenerated catalyst from the regenerator to the reactor), thus controlling coke deposition to make it commensurate with air supply by controlling the severity and conversion level in the reactor. The temperature in the regenerator catalyst bed is held constant by varying the recycle feed rate to the reactor in response to variations in such temperature.
The process of claim 1 in which the temperature and the catalyst-to-feedstock ratio in the reactor are varied by varying the flow of hot regenerated catalyst from the regenerator to the reactor.
Claim 2
Dependent Claim
230 words
In a catalytic cracking unit consisting essentially of: a. A reactor having a first conduit attached to the upper portion thereof, a stripper attached to lower portion thereof, and a temperature recorder controller alarm attached to said reactor; b. a regenerator having attached to the upper portion thereof a second conduit and means to control the pressure in the regenerator, and having attached to the lower portion thereof a third conduit, equipped with a valve, said third conduit extending up into the lower portion of the regenerator, and a fourth conduit connected to the lower portion of the regenerator, said fourth conduit having an air compressor connected thereto; c. means for controlling the operation of said valve in response to temperature variations in the reactor; d. a fifth conduit connecting the lower portion of the reactor with the bottom end of said third conduit and extending beyond said connection to connect with a sixth conduit for fresh feed and a seventh conduit for recycle feed; e. flow rate control means in each of said sixth and seventh conduits; f. temperature-sensing means connected to the upper portion of the regenerAtor, said temperature-sensing means being operatively connected to said means (c); The improvement which comprises: g. Temperature-sensing means connected to the lower portion of the regenerator, said temperature-sensing means being operatively connected to said flow rate control means in said seventh conduit.
Claim 3
Dependent Claim
38 words
The combination of claim 3 wherein said temperature sensing means (g) comprises temperature control means for changing the control setting of said flow rate control means in response to temperature variations in the lower portion of the regenerator.