RU2345121C1 - Liquid-phase thermal cracking reactor - Google Patents

Abstract

FIELD: toil and gas industry.

SUBSTANCE: invention can be used for thermal fuel oil cracking and following production of gasoline fraction and diesel oil cut. Stock heated in pipe-still heater is supplied through one horizontal fitting pipe 4 to cups 2 and 3. These devices through fitting pipes 5 receives activating agent that is thermal cracking steam or gases. Owing to cross-slide injection of stock and steam, vertical helical stream is generated in cups 2 and 3. Centrifugal effort discharge arranged helical stream from the rector. Produced liquid light products of thermal cracking fitting pipe 6, and gaseous products through fitting pipe 7. Heavier fraction is removed from lower part of reactor through fitting pipe 9. Thus in reactor, counter-current cross-flow of liquid can be observed in reactor.

EFFECT: higher efficiency of thermal cracking due to lower reactor carburising degree.

2 cl, 2 dwg

Description

The claimed invention relates to the refining industry, in particular to devices for the implementation of thermal cracking and visbreaking processes, and can be used in the thermal cracking of fuel oil with subsequent production of gasoline and diesel fractions and cracking residue.

Various reactor designs are known for liquid phase thermal cracking of petroleum feeds. See, for example, UK patent No. 2094336, 1981, US patent No. 4551233, 1984, Russian patents No. 2021995, 1994, 2137804, 1996 and others. The main disadvantage of the known solutions is the insufficient efficiency of the cracking processes carried out at the reactors, and as a result of the inability to discretely control the time of the thermal cracking process while maintaining the reactor productivity.

The closest known to the claimed is a reactor for liquid-phase thermal cracking (see Russian patent No. 2137804, publ. 25.11.96). This reactor consists of an external vessel — a vessel with an integral vessel in the form of a tube integrated motionlessly and coaxially inside it, under which there is a jet-forming device made in the form of curved blades radially diverging from the center. At least one steam mother liquor is installed above the jet forming device, placed in the cavity between the body and the inner pipe and made in the form of a torus, equipped with a nozzle for supplying water vapor and output nozzles with an angle of inclination to the radius of the torus of 30-60 °, preferably 45 °.

The disadvantage of the above reactor is not a sufficiently high process efficiency, due to the fact that:

firstly, during the operation of the reactor, coking of the inner pipe and the jet forming device occurs soon enough, which necessitates its frequent shutdown for cleaning. This is due to the low turbulence of the feed stream in the reactor volume, which contributes to the formation of stagnant zones;

secondly, there is no possibility of discrete regulation of the time spent by the reaction mass in the reaction zone without reducing the productivity of the process;

thirdly, the structural complexity of the jet-forming device creates difficulties in the manufacture of the reactor as a whole.

The technical task of the proposed solution is to simplify the design of the reactor, increase its reliability and at the same time provide an increase in the efficiency of the thermal cracking process by reducing the degree of coking of the reactor by creating conditions for organizing effective rotational movement of the feed stream and mixing it with steam or thermal cracking gases during their tangential feed .

The problem is solved due to the fact that in the reactor for liquid-phase thermal cracking, consisting of a cylindrical body, in which there are devices for introducing raw materials and an activating agent - superheated steam or thermal cracking gas, and an upstream flow forming device, and in the lower part the reactor is equipped with a device for steam supply, input device of raw material and activating agent and flow forming device are combined in one supply unit, made in the form of several single axially aligned with the housing n cup above the other, in each of which a tangentially mounted nozzles for supplying raw material and for supplying an activating agent. In this case, all glasses, except the lower one, are located downwards and upstream disks are attached to their bottoms, and the lower one is located upside down. In addition, in the upper part of the housing an additional pipe is installed for the removal of thermal cracking gases. The diameter of the disks attached to the bottoms of the glasses is not more than 0.6 of the diameter of the reactor.

The technical result is achieved due to the fact that in the glasses, due to the joint tangential introduction of the raw material and the activating agent along the same guideline, the flow is turbulized, which prevents coke from settling both on the walls of the glasses and on the reactor itself (its body). Moreover, the location of the lower glass upward directs the flow to the lower part of the reactor, thereby achieving the organization of turbulent flow throughout the reactor volume and a significant reduction in the number of stagnant zones. The ability to remove thermal cracking gases by means of a pipe installed in the upper part of the vessel allows obtaining a better liquid product for further processing at the outlet of the reactor, as well as using thermal cracking gas as an activating agent.

In figure 1. shows a reactor for liquid-phase thermal cracking in the context, figure 2 is a view aa of figure 1.

The reactor for liquid-phase thermal cracking consists of a housing 1. Coaxially with it, a feeding unit is integrated in the housing, including glasses 2 and a lower glass turned upside down 3. In glasses 2 and 3, nozzles for tangential supply of 4 and for supply of activating agent 5 are installed tangentially. 6 - nozzles for the exit of liquid light reaction products, and 7 - nozzle for the exit of thermal cracking gases. In the lower part of the reactor there is a hatch 8 for removing coke-like products during the cleaning of the reactor with pipe 9 for removing heavy cracked residue. 10 - a device for supplying steam to the reactor during its operation or purification. At the bottom of the koprus there is a pipe 11 used for drainage. Disks 12 are attached to the bottoms of the glasses 2.

The reactor operates as follows. The raw material after heating in a tube furnace is fed through one of the horizontally arranged nozzles 4 into the glasses 2 and 3. The activating agent — steam or thermal cracking gases — is supplied to the same devices through the nozzles 5. Due to the tangential introduction of raw materials and steam in the glasses 2 and 3, a rotational spiral flow is formed. Under the action of centrifugal force, an organized spiral flow is removed from the rector. Because input of raw materials is carried out at one of the four points of the reactor located at different heights, this makes it possible to discretely control the passage of raw materials through the reactor and, therefore, affect the cracking depth. The resulting liquid, light thermal cracking products are discharged through nozzle 6, and gaseous ones are discharged through nozzle 7. The heavier fraction is discharged from the bottom of the reactor through nozzle 9. Thus, a cross-counterflow liquid flows in the reactor. This leads to an increase in heat transfer between the liquid layers and a decrease in coke formation.

Thus, the proposed technical solution allows you to enhance the effect of twisting the reaction mass of raw materials in the reactor, preventing coking, which improves operating conditions and increases the life of the reactor. And the possibility of discrete regulation of the thermal cracking reaction time contributes to a significant increase in the value of the cracking depth and the stability index of the obtained product, i.e. improving its quality.

Claims (2)

1. The reactor for liquid-phase thermal cracking, consisting of a cylindrical body, which contains input devices of raw materials and an activating agent and a device for forming an upward flow, and is also equipped with a device for supplying steam to the reactor, characterized in that the reactor is equipped with a feed unit combining the functions of the input devices of raw materials activating agent and the formation of the flow, made in the form of several glasses arranged coaxially with the body one above the other, in each of which nozzles for tangentially mounted Aci raw material and activating agent, all tumblers, except the lowest, disposed down to their bottoms and the bottoms of wheels attached-way valves upstream and the lower bottom is up, in addition, the upper housing portion is mounted an outlet for removing thermal cracking gases. 2. The reactor according to claim 1, characterized in that the diameter of the disks attached to the bottoms of the glasses is not more than 0.6 of the diameter of the reactor.

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