RU2536590C1 - Plant for thermal destruction of oil residues - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: invention relates to the plant including heating kiln for stock thermal destruction. It comprises reactor with stock feed top pipe, pipes for discharge of vapour and liquid phases of thermal destruction products. Said reactor is equipped with cooling jacket with coolant feed and discharge pipes communicated with rectifier circulation irrigation. Note here that said reactor incorporates extra bottom stock feed pipe for simultaneous feed of heat-treated stock into reactor. Stock feed pipes are furnished with cooling jackets while the plant comprises extra initial stock mixers.

EFFECT: higher efficiency, lower carburizing of feed pipe surfaces.

2 cl, 1 dwg

Description

The invention relates to oil refining, in particular to thermal decomposition plants for processing oil residues (visbreaking, thermal cracking).

A known visbreaking installation, including a furnace for heating the oil residue-tar, an external reaction chamber (socking chamber) with an upward flow of cracking products, distillation and vacuum columns for the separation of thermal decomposition products with the outlet of gas, gasoline, light and heavy gas oils and residue (Efremov A .V et al. Commissioning of a new visbreaking unit at OAO Salavatnefteorgsintez // KhTTM 2010, No. 4, p.14-18).

A disadvantage of the known installation is the coking of the inner surface of the reactor, accompanied by a decrease in the depth of decomposition of raw materials and the quality (viscosity) of the obtained product.

A known installation for thermal decomposition of oil residues (options), including a furnace for heating raw materials, a remote reactor for thermal decomposition with nozzles for introducing raw materials and output steam and gas thermal decomposition products into a distillation column for separating thermal products, heat exchangers. The reactor is equipped with a cooling jacket with nozzles for the input and output of the cooling agent — circulating column irrigation and is additionally equipped with a nozzle for supplying a “cold stream” - bottom residue of the column. According to the first embodiment, the raw material input pipe is located in the upper part of the reactor, and the pipe for supplying a “cold stream” is located in the lower part. According to the second variant, the raw material input pipe is located in the lower part of the reactor, the “cold stream” pipe in the upper part, and plates of a failure type (Pat. RF No. 2318859, March 10, 2008, Bulletin No. 7, IPC C10G 9 / 00).

As a prototype, the installation for thermal destruction according to the first embodiment was selected.

A disadvantage of the known invention is the insufficient use of heat of vapor-gas products for thermal decomposition of the liquid phase due to the release of vapors from the reactor without contact with the reaction mass, as well as coking of the surface of the inlet pipes.

The technical result, the achievement of which the present invention is directed, is to increase the efficiency of heat utilization of combined-cycle products, as well as to reduce the coking of the surface of the inlet pipes.

To achieve the technical result, an apparatus for thermal decomposition of oil residues, including a furnace for heating and thermal decomposition of raw materials, a reactor with an upper pipe for inputting raw materials and pipes for outputting steam and liquid phases of thermal decomposition products, the reactor is equipped with a cooling jacket with pipes for inputting and outputting a cooling agent, which are connected with a line for circulating irrigation of a distillation column, according to the invention, the reactor is additionally equipped with a lower raw material input pipe for simultaneous the input of heat-treated raw materials into the reactor, while the pipes for the input of raw materials are equipped with cooling jackets, and the installation additionally contains tanks - mixers for the feedstock.

Shirts for cooling the pipes are connected to the circulation line of the distillation column.

With the simultaneous introduction of heat-treated raw materials into the reactor through the upper and lower nozzles, gas-vapor products are removed from the upper part of the reactor, and the liquid phase, descending into the lower part in countercurrent to rising vapor phase bubbles from the lower stream during direct heat and mass transfer, receives latent heat of vapor condensation from them, increases its heat content (enthalpy), temperature and undergoes further thermal degradation, thereby increasing the efficiency of the process.

In addition, the simultaneous introduction of heat-treated raw materials into the reactor through the upper and lower nozzles allows the heavier of them, the most prone to coking, to be heated in the furnace coil to a lower temperature (460 ° C) with a lower conversion and introduced into the upper part of the reactor, and lighter raw materials, less prone to coking to send with a higher temperature (500 ° C) with a higher conversion to the lower part of the reactor, which allows to obtain a given total conversion of raw materials and a given quality (viscosity) of the product in the reaction D while increasing overhaul life of the furnace coils and the system.

The cooling shirts installed on the raw material inlet pipes prevent their coking.

The attached figure shows the installation diagram for thermal destruction of oil residues.

The installation includes a line 1 for supplying the initial heavy raw materials: tar (with a density of more than 1000 kg / cubic meter, asphalt), line 2 for supplying lighter raw materials (semi-tar, fuel oil, gas oil), mixing tanks 3, 4 for preparing raw material compositions, a line 5 (gas oil) recirculating diluent of heavy oil residues, feed composition feed lines 6, 7, reaction-heating coils 8, 9 of the tube furnace 10 for heat treatment (cracking) of feed compositions, transfer lines 11, 12, upper pipe 13 for introducing heat-treated raw materials to the top of the rea torus 14, lines 15 and 16 for input and output of the cooling product (gas oil) into the cooling jacket 17 of the nozzle 13, the reactor cooling jacket 18, the cold stream supply line 19, 20 of the cooled bottoms, the nozzle 21 and the vapor-gas products outlet line 22 thermal decomposition of residues from the top of reactor 14, valve 23 — pressure regulator in reactor 14, distillation column 24 for separating thermal decomposition products into components: gas, gasoline, water condensate, light and heavy gas oils, bottoms, recycle (gas oil), pipe 25 for input thermo processed raw materials to the lower part of the reactor 14, lines 26 and 27 for introducing and outputting the cooling product (gas oil) into the cooling jacket 28 of the pipe 25, pipe 29 and the output line 30 of liquid thermal decomposition products of residues from the bottom of the reactor 14, valve 31 is a phase separation level regulator in reactor 14, cascade trays 32 of distillation column 24, cold stream lines 33, 34, solid dynamic film 35 inside reactor 14, cooling product line 36 for jacket 18, refrigerator (heat exchanger) 37, circulation irrigation (gas oil) 38 columns 24, lines the output of thermal decomposition products from the column 24: 39 - gas, gasoline, water; 40 - fractions of light gas oil, 41 - heavy gas oil, 42 - bottoms, stripping columns 43 and 44 of light and heavy gas oil, respectively, acute irrigation 45 with gasoline, water vapor 46, refrigerator (heat exchanger) 47 bottoms, line 48 "cold stream" , line 49 of boiler fuel, lens compensator 50 of cooling jacket 18, breathing lines 51 of mixing tanks 3, 4.

The proposed installation works as follows.

Raw components - tar (asphalt) 1, semi-tar (fuel oil) 2 preheated in heat exchangers (not shown), are fed into mixing tanks 3, 4, respectively, where, after mixing with recycle 5 (gas oil diluent) in a predetermined ratio, the raw materials compositions along lines 6, 7 enter the coils 8, 9 of the tube furnace 10, where they are heated by burning fuel to a temperature of 460-500 ° C. The heat-treated (cracked) feedstock along lines 11, 12 is respectively introduced simultaneously through nozzles 13 (heavy), 25 (light) into the upper and lower parts of the reactor 14 with a cooling jacket 18 to continue the thermal degradation of oil residues due to the heat accumulated in the furnace 10. Regulation the temperature of the flows 11, 12 at the inlet to the reactor 14 is produced by supplying a "cold stream" along lines 19, 20, respectively. Combined gas and thermal decomposition products of the residues along the pipe 21 are removed from the upper part of the reactor 14 via line 22 through the pressure control valve 23 to the distillation column 24 for separation.

The liquid phase of the thermal product, descending into the lower part of the reactor 14 in countercurrent to the rising vapor phase bubbles from the lower stream 25 during direct heat and mass transfer, receives from them the latent heat of vapor condensation, increases its heat content (enthalpy), temperature and undergoes further thermal decomposition. A mixture of liquid products of thermal decomposition of raw materials is discharged through pipe 29 along line 30, a valve-regulator of the phase separation level 31 to the lower part of the column 24 above the cascade plates 32 for separation. To reduce the temperature of the stream 30 at the inlet of the column 24 to 380-420 ° C, it is chilled with a "cold stream" coming through lines 33, 34.

The coking of the inner surface of the reactor 14 is prevented by cooling it to a temperature below the temperature limit of the cracking of the feed (about 250 ° C). The components of the reaction mass having a pour point above 250 ° C, adhere to the "cold" wall of the reactor and form a solid dynamically stable film 35, which protects it from coking. To cool the walls of the reactor 14, it is equipped with a cooling jacket 18, into which a cooling product is introduced via lines 36 — circulation irrigation (gas oil) 38 columns 24 cooled in the refrigerator (heat exchanger) 37. The inlet pipes 13, 25, which are also introduced, are protected in a similar way cooled stream 36. The cooling product is removed from the protective shirts (17, 18, 28) through lines 38. In the rectification column 24, the products are obtained in the rectification process: gas, gasoline, water condensate 39, light 40 and heavy 41 gas oils, bottoms 42 ( boiler component fuel, “cold stream”) and recycle (gas oil) 5. Light and heavy gas oils are discharged through stripping columns 43, 44, respectively. To ensure the rectification process and obtain products of a given quality, acute irrigation (gasoline) 45, circulating irrigation (gas oil) 38 and water vapor 46 are supplied to column 24, the latter is also fed to stripping columns 43, 44. The temperature of the bottom residue 42 is reduced in the refrigerator (heat exchanger ) 47 by transferring heat from the bottom residue 42 with raw materials 1, 2, followed by using part of the bottom residue as a “cold stream” (streams 19, 20, 33, 34), including to reduce the temperature of the bottom of the column 24 by stream 48. To obtain boiler fuel 49 to the bottom residue 42 add diluents: light 40 and heavy 41 gas oils in the required amount. The cooling jacket 18 is provided with lens compensators 50. The breathing tubes 51 of the mixing tanks 3, 4 are led into the column 24.

The present invention allows to increase the efficiency of the process of thermal decomposition of oil residues, to obtain the desired quality of the product and at the same time increase the turnaround time of the installation.

Claims (2)

1. Installation for thermal decomposition of oil residues, including a furnace for heating and thermal decomposition of raw materials, a reactor with an upper pipe for input of raw materials and pipes for the output of steam and liquid phases of thermal decomposition products, and the reactor is equipped with a cooling jacket with pipes for input and output of a cooling agent, which are connected to the circulation line distillation column irrigation, characterized in that the reactor is additionally equipped with a lower pipe for the input of raw materials for simultaneous input of heat-treated raw materials into the reactor, while the pipe The raw material input kits are equipped with cooling jackets, and the installation additionally contains mixing tanks for feedstock. 2. Installation according to claim 1, characterized in that the shirts for cooling the pipes are connected to the circulation line of the distillation column.

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