RU2444401C1 - Installation of oil processing and petrochemical processes on heterogeneous catalysts - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to thermocatalytic processes in oil processing and petrochemistry. It covers said processes in heterogeneous catalysts, e.g. zeoforming, Z-forming, cyclar, reforming, catalytic cracking, catalytic destruction of natural gas liquids, to be realised at installation consisting of process reactor, catalyst regenerator, stock heating and evaporation furnace, gate feeders, filters, rectification assembly and flue. Reactor and regenerator are made up of spiral conveyors furnished with jackets to allow isothermal processes. Note here that moving heterogeneous catalyst and gas flow are in countercurrent in both reactor and regenerator. Reactor and generator are installed inclined to horizontal line to allow spiral conveyors in both reactor and regenerator rising catalyst which necessary to transfer catalyst from rector into regenerator via gate feeders. Reaction produces are discharged from filter into rectification assembly for separation while flue gases are forced through filter and into atmosphere.

EFFECT: higher efficiency.

3 cl, 4 dwg

Description

Known installations for carrying out thermocatalytic processes of oil refining and petrochemicals: cyclar (JOP, USA) [1], Z-forming (Japan) [2], zeoforming (Russia [3], IC SB RAS) and catalytic cracking.

The essence of these processes is that the feedstock is straight run or gas gasoline, a wide fraction of light hydrocarbons, the pentane or hexane fractions of oil are heated, evaporated and overheated in a tube furnace, and then introduced into the reactor with a layer of a heterogeneous catalyst, in the interaction with which the desired effect: the conversion of raw materials molecules to the molecules of a given product.

Processes with a moving catalyst bed are also known, such as reforming with continuous catalyst regeneration [1], oleflix, butylene isomerization, or processes with a fluidized catalyst bed, for example, catalytic cracking of heavy oil distillates. They are taken by us as an analog.

Since the conversion reaction is, as a rule, exotemic, heat supply to the feed-catalyst system is required (as is customary, for example, in a catalytic reforming unit [2]). For this purpose, the raw materials are removed from the reactor, heated in a furnace, and then introduced into the next reactor due to the high specific heat of the reaction, this maneuver has to be carried out up to 4 times and the reactor is structurally performed in 4 separate stages, between which the furnaces are located, regardless of type process, it occurs in a stationary or in a moving catalyst bed. The installation consists of several steps. This greatly complicates, increases the cost and thereby worsens technical and economic indicators. This installation is accepted by us as a prototype.

In processes with a moving or fluidized catalyst bed, the vertical transport of the latter from the regenerator to the reactor and vice versa is difficult due to their high height.

In processes such as catalytic cracking, carried out in a fluidized bed of a catalyst, overheating of the catalyst in the regenerator is used to achieve the desired conversion depth of the feedstock and supply the necessary heat, which leads to the formation of more gas and coke, because as the process temperature rises, their yield increases significantly, i.e. the selectivity of the process is reduced.

To reduce the temperature of the catalyst increase the frequency of its circulation (up to 10 times) [5], which increases capital and operating costs.

This installation is accepted by us as an analogue.

Another distinctive property of these processes is a decrease in catalyst activity due to the gradual deposition of coke on the catalyst.

In known installations for the regeneration of the catalyst [3], coke is periodically burned with atmospheric oxygen. However, the ingress of a high concentration of oxygen into the catalyst layer leads to local overheating of the catalyst grains, a decrease in its activity and its failure, and to avoid this, the catalyst is regenerated by a gas mixture with a successively increasing oxygen concentration from 1-2% to 21%, burning coke , which requires additional complex hardware design and energy consumption.

It also significantly complicates, increases the cost and thereby worsens the technical and economic indicators of the process.

So, during the process, coking of the catalyst occurs. It is especially intense in the interaction of a freshly-prepared catalyst with fresh raw materials that have not yet come into contact [4].

However, in the adopted schemes of the plants carrying out the processes under consideration, this phenomenon could not be completely eliminated.

The proposed installation makes it possible to carry out the processes under consideration, excluding stepwise inter-reactor heating of the feed and burning of coke gas with a sequential change in time of the oxygen concentration in the regeneration gas in countercurrent flow of the catalyst and regeneration gas.

In addition, it was possible to significantly increase the efficiency of the process due to tedding of the catalyst during its movement along the reactor.

It was also possible to avoid the ingress of fresh raw materials to the freshly regenerated catalyst, but to supply fresh raw materials to the spent catalyst, and partially reformed raw materials to the fresh catalyst.

The essence of the invention is that:

- The process is carried out in a reactor with a moving catalyst.

- A spiral conveyor is used as a catalyst mover, which made it possible to significantly intensify mass transfer processes, to exclude complex systems for raising the catalyst during its transport from the regenerator to the reactor and vice versa, including pneumatic transport.

- The heat is supplied for the reaction in a tube-in-tube heat exchanger, the tube space of which is a spiral reactor, and the tube space encircling the reactor, through which the flue gases of the process furnace are passed, which thus serves as the convection section of the furnace, which allowed carry out the process isothermally and eliminate the interstage heating of the raw materials in the furnaces or overheating of the catalyst in the regenerator for supplying the required amount of heat to the process in exothermic reactions.

- The catalyst regenerator is also a spiral conveyor.

- Both the reactor and the regenerator are located obliquely to the horizontal and they work to raise the catalyst to the height necessary to move from one to the other through the gate feeders.

- Both in the reactor and in the regenerator countercurrent gas and catalyst.

- The catalyst is regenerated by burning coke with atmospheric oxygen without overheating of the catalyst due to the counterflow of gas and catalyst. In this case, an already regenerated catalyst is supplied to the zone of high oxygen concentration, and the coked catalyst falls into the zone of low oxygen concentration.

- In the same way, in a reactor, a freshly regenerated catalyst interacts with a low concentration of unreacted feed molecules, and a coked catalyst reacts with fresh feed. This significantly reduces the coking process.

- A large amount of coke is formed in catalytic cracking, as the process is associated with a significant relief of products, and when coke is burned, heat is generated that is sufficient to produce cracking. It is proposed to transfer heat from the regenerator to the reactor not only through the catalyst, but also through flue gases, excluding the furnace from the process scheme, or at least significantly reducing its heat production, as well as reducing the temperature and the frequency of circulation of the catalyst.

Figure 1 shows the installation diagram of the type of zeoforming.

1. Raw materials.

2. Technological fire tube furnace.

3. Fuel to the stove.

4. Evaporated and superheated raw materials.

5. The reactor.

6. Filter.

7. Rectification unit.

8. Liquid reaction products.

9. Gaseous reaction products.

10. The conveyor spiral is the mover of the catalyst.

11. The motor-reducer-drive spiral.

12. The catalyst regenerator.

13. Nitrogen.

14. Gateway feeder (shutter).

15. Air for burning coke.

16. Refrigerant (water or air) to remove heat from the combustion of coke.

17. Shirt regenerator-heat exchanger "pipe in pipe".

18. Nitrogen.

19. Gateway feeder (shutter).

20. The jacket of the reactor pipe-to-pipe heat exchanger.

21. The chimney.

22. The spiral of the regenerator.

23. Motor gearbox drive spiral.

24. Flue gas regeneration.

25. Filter.

Figure 2 shows a diagram of the installation of catalytic cracking of oil, heavy oil residues or heavy and medium distillates.

1. Raw materials.

2. Technological fire tube furnace.

3. Fuel to the stove.

4. Evaporated and superheated raw materials.

5. The reactor.

6. Filter.

7. Rectification unit.

8. Liquid reaction products.

9. Gaseous reaction products.

10. The conveyor spiral is the mover of the catalyst.

11. The motor-reducer-drive spiral.

12. The catalyst regenerator.

13. Nitrogen.

14. Gateway feeder (shutter).

15. Air for burning coke.

16. Refrigerant (water or air) to remove heat from the combustion of coke.

17. Shirt regenerator-heat exchanger "pipe in pipe".

18. Nitrogen.

19. Gateway feeder (shutter).

20. The jacket of the reactor pipe-to-pipe heat exchanger.

21. The chimney.

22. The spiral of the regenerator.

23. Motor gearbox drive spiral.

24. Flue gas regeneration.

25. Filter.

26. Raw material pump.

27. Blower.

28. Heat recovery boiler.

Fig. 3 shows an approximate layout of the main units of the installation.

29. The junction of the two parts of the regenerator.

30. The junction of the two parts of the reactor.

Fig. 4 shows a structural diagram of the junction of the two parts of the reactor.

31. A spiral cut into two parts.

32. The shirt of the device.

33 and 34. Additional spiral drives.

35. The housing (pipe) of the reactor or regenerator.

Processing of raw materials 1 - straight-run or gas gasoline, BFLH (a wide fraction of light hydrocarbons) or some other hydrocarbon product begins with its heating, evaporation and overheating to the required temperature in the radiation section of the technological furnace 2 by burning fuel 3 (see. one).

Hot raw materials 4 in a gaseous state are sent to the reactor 5, where interacting in countercurrent with a heterogeneous catalyst, a predetermined reaction of its transformation occurs. The reaction products are removed from the reactor through a filter 6 and sent to the distillation unit separation 7, from where it is sent to consumers in liquid 8 or gaseous 9 form.

The catalyst mover is a spiral 10.

To exclude the ingress of raw materials 1 into the regenerator 12, nitrogen 13 is supplied to the upper part.

The coked catalyst through the gate feeder (gate) 14 [5] falls into the regenerator 12, where coke deposited during the reaction is burned out of the catalyst in a countercurrent to the regenerating gas - air 15.

Heat removal from the combustion of coke is carried out with a refrigerant 16 (for example, water or air) through the jacket 17.

To prevent oxygen from entering the reactor 5, nitrogen 18 is supplied to the upper part of the regenerator 12.

The regenerated catalyst is dumped from the regenerator into the reactor through the gateway feeder 19.

Heat for producing a reaction is supplied through the wall of the reactor 5 from the jacket 20 from the flue gases of the furnace 2. Flue gases are discharged from the jacket 20 into the chimney 21.

The spirals 10 and 22 of the reactor and regenerator are driven into rotation by a gear motor 11 and 23.

The flue gases of the regeneration 24 are discharged into the chimney 21 through the filter 25.

The catalyst dust captured by the filters 6 and 25 falls off the filter surface back into the movement zone of the spirals 10 and 22.

Filter regeneration is carried out by short-cycle reverse purge [6], [7], [8].

The implementation of the countercurrent of the catalyst and gas both in the reactor and in the regenerator makes it possible:

- Interactions of the fresh regenerated catalyst with the reacted feed, excluding such contact with the fresh feed, and thereby reduce coking of the catalyst.

- The gradual introduction of air 15 and flue gas exhaust from the combustion of coke of the regenerated catalyst allows coke to be burned in a gradually decreasing oxygen concentration, which automatically prevents overheating of the catalyst grains.

It is advisable to make the filtering surface of filters 6 and 25 from stainless steel mesh and perform the filter itself with short-cycle reverse blowing [6], [7], [8].

A small hydraulic resistance to the gas flow of the reactor and regenerator allows the use of industrially produced gateway feeders (gate locks), for example, rotary, for catalyst flow.

The apparatuses of the installation fit well with each other and, as a whole, are a clearly interacting and easily adjustable ensemble.

In catalytic cracking units for a reactor, the principle of fluidization in a dense catalyst bed is used, and for a regenerator with a fluidized discharged catalyst bed. Moreover, the heat of combustion of coke fully compensates for the costs of cracking.

The use of reactors in the form of a spiral conveyor removes the problem of a high rate of catalyst circulation since both cracking and coke burning processes can be carried out in isothermal conditions, and heat can be transferred from the flue gases to regeneration.

Of course, the temperature in the reactor should be slightly lower than the temperature in the regenerator. But this temperature difference can be significantly reduced several times by breaking the jacket of the reactor into several parallel sections.

The operation of the catalytic cracking unit with the proposed reactors can be traced according to the scheme of Fig. 2.

Raw material 1 is pumped to the regenerator jacket, where it is heated to the process temperature and partially or completely evaporated 4, and then sent to the reactor 5, where the catalyst moves the spiral 2 of the conveyor. The reaction products are removed from the reactor through a filter 6 and sent for distillation to a rectification unit 7, from which liquid and gaseous products 8 and 9 are removed.

The spent catalyst is dumped through the lock feeder (gate) 14 [5] into the coil 22 of the regenerator 12. The catalyst is regenerated by air 1 from the blower 27.

Hot flue gases regeneration 24 through the filter 25 is sent to the jacket 20 of the reactor 5. The cracking reaction is carried out due to the cooled flue gases regeneration, the latter are released into the atmosphere through the chimney 21.

It is possible to utilize the heat of flue gases by a waste heat boiler 28 or for heating air 15 or raw materials 1.

Due to the specific residence time of the feedstock and the catalyst (in most processes, 15-20 minutes) and the speed of gases in them, both the reactor and the regenerator of the type of spiral conveyor should be limited, on the one hand, by the mass transfer efficiency, and, on the other, by the ablation of the catalyst, a large length (usually 20-50 m), which sometimes complicates the layout of the installation and also requires compensation for the elongation of the apparatus due to thermal expansion.

And since very heavy and stationary devices are rigidly attached at both ends of these devices, the location of both the reactor and the regenerator in one line is difficult.

In this case, it is proposed to use the adaptation of the joint of two sequential spiral conveyors worked out on industrial systems for transporting bulk solids [5].

In terms of the location of the apparatus, the installation looks as shown in Fig. 3. All heavy stationary devices are integrated in one line (shown by a dot-dash line) and reactor 5 and regenerator 12 are each divided into two parts articulated by devices 29 and 30, a structural diagram (vertical section) is shown in Fig. 4. These joints are quite compact and relatively light, so they can move freely on a flat surface as the devices elongate thermally. It is seen that the catalyst can freely fall from the upper end of the dissection of the spiral into the lower.

This maneuver makes it possible to reduce the area occupied by the reactor unit, to concentrate all heavy stationary devices in one place, which allows to halve the length of the used spirals, to use additional spiral drives 33 and 34; provide a vertical transfer of the catalyst in flows from the reactor to the regenerator and vice versa and ensure the smooth operation of the gateway (rotor) feeders [5].

Information sources

1. Symposium on conversion of LPG to aromatics and olefins, UOP / BP cyclar process UOP oleflix process VNIPINEFT, Moscow, Feb. 1992.

2. "Z-forming process: conversion of LPG and light naphtha to aromatics", 1992, NPRA ANNUAL MEETING, march 22-24, 1992, Marriot / Sheraton, New Orleans, Louisiana, Chiyoda Corporation.

3. The process of zeoforming. Institute of Catalysis SB RAS.

4. A method of processing a wide fraction of light hydrocarbons and associated petroleum gases. RF patent №2114895 from June 10, 1998

5. I.I. Shargorodsky. “Reconstruction, modernization and technical re-equipment of bulk and packaged flour storage warehouses, preparation of flour for production, in-plant transportation, dosing, metering of flour and liquid ingredients at bakeries and other food enterprises.” M. "AGRO-3", 2008.

6. V.Yu. Orlov, A.M. Komarov, L.A. Lyapina. Production and use of carbon black for rubber. Yaroslavl, publishing house Alexander Rutman, 2002.

7. Handbook on dust and ash collection. Under the total. Ed. A.A. Rusanova, "Energy", 1975.

8. Application for a patent of the Russian Federation 2010120320 dated 05/21/2010.

Claims (3)

1. Installation for carrying out oil refining and petrochemical processes on heterogeneous catalysts such as zeoforming, Z-formation, cyclar, reforming, catalytic destruction of NGL, catalytic cracking, consisting of a process reactor, catalyst regenerator, furnace for evaporation and heating of raw materials, gateway feeders (gates) filters, distillation unit and chimney, characterized in that as the reactor and regenerator use spiral conveyors equipped with jackets that allow the isotope process ically; in this case, a countercurrent of a moving heterogeneous catalyst and gas was carried out both in the reactor and in the regenerator; the reactor and regenerator are installed obliquely to the horizontal so that the spiral conveyors of both the reactor and the regenerator work to lift the catalyst, which is necessary to move the catalyst from the reactor to the regenerator and from the regenerator to the reactor through gateway feeders (gates), the reaction products from the reactor are removed through a filter in the rectification unit for separation, flue gases are discharged through the filter into the chimney. 2. Installation according to claim 1, characterized in that as filters used bag filters made of stainless mesh with a short pulsed backflush. 3. Installation according to claim 1, characterized in that the reactor and the regenerator in case of their large length can be divided into two parts, while the dissected ends are placed one above the other so that the catalyst can freely pour from one part of the spiral conveyor to another, and the beginning and end of the reactor and the regenerator would be in line with the rest of the heavy apparatus of the installation: the chimney, furnace and filters.

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