RU2841364C1 - Laboratory reactor for simulating coke formation processes on its walls - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a laboratory reactor for simulating processes of coke formation on its walls during thermal catalytic cracking and for testing methods of reducing coking capacity. Reactor has a temperature-controlled housing in form of a tube with sealing elements on its ends, wherein the reactor housing is detachable on the entire length of its inner volume and consists of coaxially mounted on each other with a minimum clearance of three connected flat discs. On surfaces of the upper and lower disks facing the central disk there are cavities in the form of “Archimedes spirals” that are interconnected through a hole in the central disk and are the internal volume of the reactor. In the body of the upper and lower disk there are pockets for control thermocouples passing along all turns of the spiral cavities in close proximity to them.

EFFECT: possibility of studying neoformation processes on the inner surface of a reactor by measuring the thickness and structure of coke deposited on the walls of the reactor on its entire length.

1 cl, 1 dwg

Description

Field of technology to which the invention relates

The invention relates to the field of oil refining, namely to the process of new formation on the walls of a reactor during thermal catalytic cracking.

Reactors are known (Chemical reactors in examples and problems. Leningrad branch of the publishing house "Chemistry" 1968. Smirnov N.N. and Volzhinsky A.I.) for thermocatalytic cracking in a fluidized bed, as well as in a fixed catalyst bed, which are a vertical thermostatted pipe with catalyst zones located in it, in which cracking is carried out, during which coke formation is observed on the catalyst and reactor walls, reducing the effective surface area of the catalyst and the rate of heat exchange between the reactor walls and the feedstock, which leads to a decrease in catalyst activity and disruption of the thermal conditions of the process. It is possible to assess the actual degree of coking of an industrial reactor only during major repairs, and it is generally impossible to assess the dynamics of the coke deposition process.

Laboratory reactors are also known, which are copies of industrial reactors reduced by tens of times, in which similar processes occur, but to study the dynamics of coke deposition, access is required to the internal surfaces of the reactors, which have an internal diameter of 10 to 40 mm and a length of 500 to 1000 mm, which requires the destruction of the reactors.

Disclosure of invention

The aim of the invention is to provide the possibility of studying the processes of new formation on the inner surface of a reactor by measuring the thickness and structure of coke deposited on the walls of the reactor along its entire length during the process of thermocatalytic cracking and developing methods for reducing coking.

The said objective is achieved by the fact that in a reactor containing a thermostatted housing in the form of a tube with sealing elements at its ends, the reactor housing is made detachable along the entire length of its internal volume and consists of three flat disks connected to each other coaxially mounted on each other with a minimum gap, while on the surfaces of the upper and lower disks facing the central disk, there are depressions in the form of "Archimedes spirals" connected to each other through an opening in the central disk, which are the internal volume of the reactor, the outlet and inlet of which are located on the upper and lower disks, respectively.

In the upper and lower disks, channels are made for control thermocouples, passing in close proximity to the turns of the spiral recesses, which are shifted in the disks relative to each other by the value of the pitch of the “Archimedes spirals”.

Description of drawings

Fig. 1 shows the proposed reactor.

Implementation of the invention

The reactor is made in the form of an easily disassemblable package of three flat disks coaxially fastened together. On the surfaces of the upper disk 1 and the lower disk 2 facing the central disk 3, depressions 4 are made in the form of "Archimedes spirals", which are the internal volume of the reactor. In the center of the middle disk 3, an opening 5 is made, connecting the beginning and the end of the volumes formed by the depressions 4 on one and the other side of the flat middle disk, which does not have depressions, which together form the internal volume of the reactor, the length of which is several meters, and the cross-section depends on the width and depth of the depression 4. To the outer surface of the disks 1 and 2, nozzles 6 and 7 are welded, connected to the beginning and the end of the channel formed by the spiral depressions 4, which are the inlet and outlet of the reactor. In the body of the upper and lower disk, pockets 8 for control thermocouples are made, passing along all the turns of the spiral depressions 4 in close proximity to them.

The device works as follows.

The reactor is heated to the operating temperature (350÷600°C), and heated raw material (bitumen, fuel oil, vacuum gas oil) is fed to its input 7 by a metering pump, which moves along the channel formed by the recess 4 in the lower disk 2 and the surface of the central disk 3, and then through the opening 5 in the middle disk 3 it enters the channel formed by the surface of the middle disk 3 and the recess 4 in the upper disk 1, which makes it possible to double the length of the reactor without increasing the dimensions of the reactor and to ensure a more uniform distribution of the thermal field along the length of the reactor. The time of movement of the raw material along the recesses 4 in disks 1 and 2, the length of which is more than five meters, can be from several hours to tens of hours. The channel formed by the recesses 4 can be partially or completely filled with a catalyst. In the process of movement along the heated channel, the raw material is transformed into light fractions, and some of it is deposited on its walls in the form of coke. Movable thermocouples 9, located in pockets 8, monitor the temperature along the entire length of the reactor with a step equal to the length of the turn of the spiral recess 4, which allows us to judge the nature of the processes in the reactor and their correlation with coke formation. The detachability of the reactor along its entire length and the presence of the middle removable disk 3, on both sides of which coke is deposited equally with the rest of the internal surface of the reactor at all stages of the process from the input of raw materials into the reactor to the output of cracking products, allows us to measure the thickness and structure of the coke layer deposited on the surfaces of recesses 4 and on both planes of disk 3 along the entire length of the reactor, which allows us to draw conclusions and make decisions on the conditions of the experiment and the composition of the raw materials in order to reduce coke formation, i.e. the set goal is achieved.

Due to the fact that the thermal conductivity of the raw material is less than the thermal conductivity of the metal, the turns of the spiral recesses 4 are shifted relative to each other by the value of the spiral pitch, which ensures more uniform heating across the internal cross-section of the reactor.

Claims (1)

A laboratory reactor for modeling coke formation processes on its walls, containing a thermostatted housing in the form of a tube with sealing elements at its ends, characterized in that the reactor housing is made detachable along the entire length of its internal volume and consists of three flat disks connected to each other coaxially mounted on each other with a minimum gap, wherein on the surfaces of the upper and lower disks facing the central disk, there are depressions in the form of "Archimedes spirals" connected to each other through an opening in the central disk, which are the internal volume of the reactor, fittings are welded to the outer surface of the upper and lower disks, connected to the beginning and end of the channel formed by the spiral depressions, which are the inlet and outlet of the reactor, wherein pockets for control thermocouples are made in the body of the upper and lower disk, passing along all the turns of the spiral depressions in close proximity to them.