RU2548088C2 - Oil coke upgrading method and gas refrigerator for coke cooling - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: inventions can be used in oil-processing and coke-chemical industry. Oil coke is calcinated and then cooled in two stages. At the first stage coke is cooled down to the temperature 1000°C in the gas refrigerator at direct contact of hydrocarbon gas with the cooling coke. At the second stage coke is cooled in a water refrigerator down to the temperature 100°C. The gas refrigerator for coke cooling contains a rotating cylindrical drum of the type "pipe in pipe" with the internal pipe (13) perforated with longitudinal cracks (16) and with tubular annulus divided into sections by longitudinal partitions (14) inside which cooling hydrocarbon gas contacting directly with cooled coke through longitudinal cracks (16) is supplied.

EFFECT: inventions allow to decrease the content of sulphur and ashes in target coke, decrease thermal internal stresses of the refrigerator wall material, to provide reliability of operation of the second cooling stage refrigerator, to increase output of target coke fraction due to decrease of its fracturing.

2 cl, 2 dwg, 1 ex

Description

The method of refining petroleum coke and a gas refrigerator for cooling coke.

The invention relates to a method for refining petroleum coke and a gas refrigerator for its implementation and can be used in the oil refining and coke and chemical industries.

A known method of calcination of petroleum coke (RU 120419 U1, C10B 1/00, 2012). The method is carried out on a petroleum coke calcination unit, which contains a sequentially arranged conveyor belt, screen, storage hopper, feeder, metering scales, raw coke screw, indirect heating coke pre-dryer, control valves, stage I-II cyclone, large and small hoppers coke oven, calcination furnace, afterburner, oiling unit, packing unit, exhaust fan, refrigerator, waste heat boiler. The specified method leads to the refinement of petroleum coke. In this case, when implementing this method, a water refrigerator is used.

The disadvantages of this method include a decrease in the yield of the target fraction due to cracking of coke due to the rapid wear of the metal wall of the water cooler due to high temperature stresses in the initial cooling zone.

Closer to the proposed method is a method of refinement of lumpy petroleum coke (Akhmetov M.M., Telyashev G.G., Karpinskaya N.N. Calcination of petroleum coke, increasing the economic efficiency of coke production at oil refineries // World of Petroleum Products, 2006, No. 4, p. 14-16).

The method is carried out by calcination (heating to 1300 ° C) and its subsequent cooling and contains two main technological processes:

- heating (calcining) coke in a rotary drum furnace from ordinary (atmospheric) temperatures up to 1200-1400 ° C (technologically preferable up to 1300 ° C) by burning liquid fuel or gas supplied from the outside. In this case, volatile substances released from the initial coke are burned, containing mainly volatile hydrocarbons, and coke breeze. In the furnace, lump coke moves by gravity due to the corresponding slope (1-4 °) of the walls and axis of the drum furnace, as well as its rotation around the longitudinal axis;

- cooling heated to 1300 ° C calcined coke in a rotating drum water cooler through the metal wall of the refrigerator, which is a tube-in-tube apparatus, into the annular space of which water is supplied with a temperature of practically no higher than 50-70 ° C, in connection with that coke should be cooled to a temperature not lower than 100 ° C. Coke in the refrigerator also moves by gravity due to the corresponding slope of the axis of the drum refrigerator and its rotation. (Akhmetov M.M., Telyashev G.G., Karpinskaya N.N. Calcination of petroleum coke, increasing the economic efficiency of coke production at oil refineries // World of Petroleum Products. - 2006, No. 4, p. 14-16).

The disadvantage of this method is the increased content of sulfur and ash in the target coke, insufficient output of the target fraction of coke, which is due to the cooling process in one stage.

Closer to the proposed gas refrigerator for cooling coke is a rotating refrigerator for cooling coke, including a horizontally mounted cylindrical heat-exchange hollow body provided with loading and unloading openings. In this case, the heat-exchange hollow casing is installed inside the outer casing, rigidly fixed with the heat-exchange hollow casing, with a gap between the casing for circulation of cooling water and the possibility of rotation. In the central part of the heat-exchange hollow case of the refrigerator, a pipe for water drainage is installed, connected to the water space between the heat-exchange hollow and the outer cases of the refrigerator in the coke loading zone of the refrigerator, with its outlet in the coke discharge zone from the refrigerator. To supply water, a pipe is installed that is connected to the water space between the heat-exchange hollow and the outer cases of the refrigerator in the coke discharge zone (RU 2209825 C1, 2003).

The disadvantage of this refrigerator is the rapid wear of the material of the inner walls of the water refrigerator due to high thermal stresses due to the significant difference in the temperature of the coke and the cooling metal wall.

Currently obtained petroleum coke with a high sulfur content (3.0 wt% and above) does not find its consumer, since it is not suitable for the production of electrode products.

The objective of the described group of inventions is to increase the efficiency of the process of refining petroleum coke.

The task in terms of the method is achieved by the described method of refining petroleum coke by calcining it, then cooling it in two stages, in the first stage to a temperature of 1000 ° C in a gas refrigerator, with direct contact of the hydrocarbon gas with the cooled coke, and then in the second cooling stage - in a water refrigerator.

The stated task in terms of a gas refrigerator for cooling coke is achieved by creating a gas refrigerator, characterized in that it contains a rotating cylindrical drum of the pipe-in-pipe type with an inner pipe having perforation in the form of longitudinal slots and with an annular space divided into sections by longitudinal partitions , which serves cooling hydrocarbon gas in contact with the cooled coke through the longitudinal slots.

The technical result of the group of inventions is to reduce sulfur and ash in the target coke due to its direct contact with hydrocarbon gas during cooling, to reduce the thermal internal stresses of the material of the wall of the refrigerator, to ensure reliable operation of the refrigerator of the second cooling stage, to increase the yield of the target coke fraction due to a decrease its cracking.

The essence of the described method is illustrated by the schematic diagram of the described method, shown in FIG. 1, where:

1 - line for supplying coke to calcination;

2 - loading hopper;

3 - rotary calcination furnace;

4 - fuel supply line;

5 - air supply line;

6 - afterburner;

7 - line for supplying hot gases from the afterburner to the waste heat boiler;

8 - gas refrigerator;

9 - a line for supplying hydrocarbon gas to a gas refrigerator;

10 - filter cleaner;

11 - water refrigerator;

12 - discharge hopper.

According to the scheme, line 1 through the feed hopper 2 feeds the petroleum coke to a rotary chamber furnace 3. If necessary, if the coke is saturated with moisture, it is heated in a special section of the furnace 3 to remove moisture (not shown in the diagram). Fuel 4 (gas and / or liquid fuel) and air 5 are fed into the furnace 3 from the outside through nozzles. As a result of combustion of the fuel, as well as coke breeze and volatiles in the furnace 3, coke is heated at the outlet of the furnace 3 in countercurrent movement to the products of fuel combustion. 1200-1400 ° C (preferably up to 1300 ° C). Unburned fuel, coke breeze, as well as "volatile" burn out in the afterburner 6, where additional air is supplied (not shown in the diagram). From the afterburner 6 through line 7, hot gases are supplied to a waste heat boiler (not shown in the diagram), in which the heat of the gases is used to produce water vapor. Heated, preferably to 1300 ° C in furnace 3, the coke is fed to a gas refrigerator 8, where it is in direct contact with the hydrocarbon gas supplied via line 9. The coke is cooled to a temperature of 1000 ° C. Gas after contact with the coke from the gas refrigerator is sent to the filter cleaner 10, where it is cleaned of sulfur and ash, after which it can be fed to the furnace 3 for combustion.

To more effectively remove sulfur and ash from coke, the gas supplied to the refrigerator 8 via line 9 is heated to a temperature of preferably not higher than 1000 ° C in a special heating furnace (not shown in the diagram).

Coke after the gas cooler 8 is sent to the water cooler 11, where it is cooled to a temperature of 100 ° C, from which it is sent to the discharge hopper 12, from where the calcined and cooled coke is fed to the warehouse.

The cooling of coke heated in a furnace in a gas refrigerator takes place in a stream of hydrocarbon gas. The gas cooler is a rotating pipe-in-pipe construction, the annulus of which is divided by longitudinal partitions into sections (at least six) for the passage of gas supplied to the annulus and exiting from it through special longitudinal slots (gaps) of at least 3 (three ) in each section for contact (purge) of gas with a layer of coke. The annular sections and longitudinal slots (slots) have a slope relative to the axis of the apparatus in accordance with the slope of the moving coke, each slot (slit) has a profile that allows this slit to be cleaned of clogging with coke breeze when the slit (slot) is at the top of the circle.

It is possible to manufacture an internal “pipe” from longitudinal rods of circular cross section with the necessary distance between the rods for gas to pass from each section to the coke, to the section above which the coke is at that moment.

In FIG. 2 shows the design of a gas refrigerator, where:

13 - inner pipe with corresponding longitudinal slots or slots;

14 - longitudinal partitions dividing the annular space into separate sections (at least 6);

15 - an outer pipe of the usual form;

16 - a slot (slot) through which coke is blown with gas;

17 - pipe outlet hydrocarbon gas from the refrigerator.

Gas refrigerator operates as follows. Pre-heated to preferably 1300 ° C, the coke enters the inner perforated pipe 13 of the refrigerator. Due to the slope and rotation of the refrigerator, coke moves inside the apparatus in the tilt direction. Towards the moving coke from the opposite side of the refrigerator, in one of the sections into which the space between the outer 15 and the inner 13 pipes is divided by longitudinal partitions 14, a cooling hydrocarbon gas is introduced. Hydrocarbon gas, passing through the longitudinal slots (slots) 16 of the corresponding section, is in contact with a layer of coke. As a result of heat and mass transfer, coke is cooled to a temperature of 1000 ° C, its partial desulfurization and ash removal. Contacted heated gas is discharged from the refrigerator through the outlet pipe 17.

Due to cooling in a gas refrigerator, coke enters a water cooler (second cooling stage) with a lower temperature, which leads to lower internal thermal stresses of the metal of its wall and a reduction in cracking of pieces of coke.

The described group of inventions is illustrated by the following example, not limiting its use.

Example.

The method is carried out according to the above scheme.

In this case, the heating temperature of petroleum coke at the outlet of the furnace 3 is 1300 °. The coke obtained in this case is cooled in the first stage to 1000 ° C in a gas refrigerator of the described construction in a stream of hydrocarbon gases (preferably not heavier than C5), in the second - in a water refrigerator to 100 ° C. As a result of the refinement process, the sulfur content in the calcined and cooled coke is reduced from 3.87% of the mass. to 0.72% wt., the ash content is reduced by 52% wt., the increase in the yield of the target fraction of coke is 10%.

Thus, the described group of inventions allows to reduce the content of sulfur and ash in calcined and chilled coke, to increase the yield of the target fraction of coke.

Claims (2)

1. The method of refining petroleum coke by calcining it and then cooling it in two stages, the first stage to a temperature of 1000 ° C in a gas refrigerator with direct contact of the hydrocarbon gas with the coke to be cooled, and then the second cooling stage in a water refrigerator to a temperature 100 ° C. 2. Gas refrigerator for cooling coke, characterized in that it contains a rotating cylindrical drum of the pipe-in-pipe type with an inner pipe having perforation in the form of longitudinal slots, and with an annular space divided into sections by longitudinal partitions into which a cooling hydrocarbon is supplied gas in direct contact with cooled coke through longitudinal gaps.

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