RU2372375C1 - Treatment method of black oil by delayed coking - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention elates to oil processing and can be used at delayed coking of black oil. Method consists of coking stage in reactor with receiving of fraction-shaped coke and stage of preparation of reactor to following coking cycling, including steaming of coke in reactor, unloading of coke from reactor in under-reactor bin, removal of water, reactor pressure testing by water steam. Stage of coking is implemented at temperature 505-530°C during 6-8 hour and under pressure not more than 0.2 MPa. Characteristics of preparation stage is unloading of coke after its steaming at temperature 390-420°C and under pressure of water steam or inert gas not less than 0.1 MPa in under-reactor bin, installed pressurised relative to reactor, herewith cooling of coke by water is implemented in under-reactor bin.

EFFECT: method provides up many times reduction of cycle duration of coking.

3 cl, 2 tbl

Description

The invention relates to the refining industry and can be used for delayed coking of oil residues.

A known method of delayed coking of oil residues (S.A. Akhmetov. Technology for the deep processing of oil and gas, Publishing House "Gilem", Ufa, 2002, pp. 385-389) by heating the raw materials in heat exchangers, convection coil of the furnace, the formation of secondary raw materials, its subsequent heating in the furnace, feeding into the reactor for coking to obtain electrode coke and subsequent preparation of the reactor for the next coking cycle.

The disadvantage of this method is that the technology used in the known method leads to a significant (48 hours) cycle time of the reactors, including the stage of filling the chambers with coke for 24 hours (actual coking) and the stage of preparation of the reactor for 24 hours, including steaming coke , cooling it with water vapor and water, removing water from the reactor, unloading coke by hydraulic cutting, heating the reactor with steam, crimping and heating the reactor with coking vapors. Then the coking cycle begins anew.

Closest to the proposed method, according to the essential features, is a method for the production and removal of shot (fuel) coke from the chamber of a delayed coking unit (International Application WO 2005/113706 A1, 01/01/2005, IPC C10 B 25/00) in which, like in the analogue, after the secondary raw materials are heated in the furnace, it is fed to the coking reactor, but various additives containing sodium and potassium cations are introduced into the raw material for the formation of shot-coke (for the formation of pellets with a diameter of 1.6-9.5 mm) iron, nickel, etc., anions sulfonic, carboxylic, salicylic, phosphoric acids, alkyl phenols, etc., the temperature of the input of raw materials into the reactor is 501 ° C, the pressure in the chamber during the working cycle is 0.1-0.5 MPa. The preparation stage includes steaming coke, cooling it with water vapor and water, discharging shot-coke in the form of a suspension of coke particles with water into an open subreactor bin, where it is further cooled and water is removed. Then the reactor is heated with water vapor, crimped and heated with coking vapors. Unloading coke together with water helps to reduce the cooling time of coke and reduce the total coking time.

The disadvantage of this method is the significant length of the coking cycle, as well as the use of expensive additives for raw materials for the formation of shot-coke,

The technical result to which the invention is directed is to reduce the length of the coking cycle in the processing of oil residues with the production of distillate and shot coke without introducing additives into the raw materials.

The specified technical result is achieved by the fact that in the method of processing oil residues by delayed coking, which includes the stage of coking in the reactor with the formation of shot coke and the stage of preparation of the reactor for the next coking cycle, comprising steaming the coke in the reactor, cooling the coke with water, discharging into the subreactor hopper, removing water from the subreactor hopper, pressure testing of the reactor with water vapor, according to the invention, the coking process is carried out at a temperature of 505-530 ° C for 6-8 hours and the pressure of water vapor or inert gas is not more than 0.2 MPa, and the shot-coke is unloaded from the reactor into the subreactor hopper at a temperature of 390-420 ° C and under the pressure of water vapor or inert gas not less than 0.1 MPa after steaming the coke in the reactor, moreover, the subreactor hopper is made with internal thermal insulation and is installed hermetically with respect to the reactor, while coke is cooled by water in the subreactor hopper.

It is advisable to steam the coke in the reactor for 2.5 hours with an increase in the consumption of water vapor from 0.5 to 10 t / h.

It is advisable to unload shot-coke into the subreactor hopper with internal thermal insulation with the upper and open lower hatches of the reactor having permanently installed remotely controlled mechanical gates.

Coking of oil residues at a temperature of 505-530 ° C for 6-8 hours and under pressure of water vapor or an inert gas of not more than 0.2 MPa allows to obtain shot-like coke without the introduction of additives, since at the specified technological mode the binder component is vaporized - gas oil (dispersion medium) from the reaction mass and the formation of grains or powder from its dispersed phase - asphaltenes, carbenes, carboids.

Unloading coke at a temperature of 390-420 ° C into a sealed subreactor bunker with thermal insulation makes it possible:

- to exclude the operation of cooling coke with water vapor, and the operation of cooling water to move to the hopper and thereby reduce the residence time of coke in the reactor;

- to maintain a high temperature in the reactor, which allows the introduction of raw materials in the next coking cycle into a hot reactor (360-370 ° C) and thereby refuse to preheat the reactor with water vapor and coking vapors before the coking stage and limit itself to pressure testing with superheated steam ( 360-380 ° C), which significantly reduces the preparation time.

The implementation of the subreactor hopper with internal thermal insulation reduces the cooling time of coke in the hopper.

All of the above features together can drastically reduce the length of the coking cycle

The method is as follows. The raw materials are preheated in heat exchangers, the convection part of the furnace and mixed with recirculate in a predetermined ratio in a separate container, then the secondary raw materials are heated in the radiation part of the furnace to a temperature of 505-530 ° C and sent to the reactor, where the coking process continues due to the accumulated heat (stage coking) with the formation of gas, gasoline, light and heavy gas oil and coke. Coke cake in the form of fractions (grains, powder) remains in the reactor, and the remaining products leave the reactor and through the helmeted pipeline enter the distillation column for separation into components. The aggregate composition of the coke cake in the form of a fraction (grains, powder) is due to the evaporation of the binder mass - gas oil from the reaction mass due to the high temperature (505-530 ° C) in it and low pressure (not more than 0.2 MPa) in the reactor.

After steaming (preparation stage) of the coke cake for 2.5 hours with superheated (360-380 ° С) water vapor into the distillation column, hot (390-420 ° С) shot-like coke by supplying water vapor or nitrogen to the reactor to maintain excess pressure in it (0.2 MPa) and when opening the remotely controlled lower gate, it is unloaded (poured) into the subreactor hopper, where overpressure (0.1 MPa) is also maintained using water vapor or an inert gas (nitrogen).

After closing the lower hatch of the reactor and pressure testing with superheated water vapor (360-380 ° C), heated raw material is supplied from the furnace to the reactor having a temperature of at least 360 ° C by switching valves accordingly for the next coking cycle. The entire cycle of operation of the reactors is repeated. Coke in a subreactor hopper is cooled with water, cooling products are sent to a petroleum recovery unit, then coke is removed, transported and stored. There are 12-16 hours for these operations, which are not included in the coking cycle, therefore it is possible to use one subreactor bin for two reactors.

The following are specific examples of the implementation of the proposed method in laboratory conditions. Tar was used as a raw material with a density of 1020 kg / m ³ , coking ability of 17%, heavy gas oil with a density of 900 kg / m ³ , coking ability of 0.3% was recirculated, it was taken to form secondary raw materials with a recycling coefficient (Cr) of 1.2 . The laboratory setup includes raw and starting tanks, a furnace loading pump, a water pump, a raw material heating furnace, a coking reactor, a heat recovery hopper with internal thermal insulation installed tightly in relation to the reactor, a coking distillate condenser-cooler, a distillate separator-receiver, a gas clock , electrical equipment and measuring instruments. The beginning and end of the coking stage was determined by the dynamics of the coking products (distillate, gas, water condensate) entering the separator receiver, gas clock.

The experiments were carried out at a pressure in the reactor of 0.15 MPa, a turbulizer-water supply of 2.5% to the furnace charge, the pressure in the reactor and subreactor hopper during unloading was 0.15 MPa.

At the end of the experiment, a material balance was drawn up, samples of coking products were taken for analysis. Analyzes of raw materials and coking products were carried out according to well-known methods adopted in oil refining. The research results are given in table.1.2.

Table 1 shows the technological mode of operation of the reactor and the products obtained by the proposed method and analogue (example 4). Table 2 shows the duration of the stages of coking and preparation of the reactor for the next coking cycle (operations) in comparison with the analogue. It is not possible to compare similar indicators with the prototype, since there are no such indicators in the description of the prototype, however, it should be borne in mind that these indicators are typical and approximately the same for such schemes and installations.

From table 2 it is seen that the operation of cooling coke with water and removing water (No. 4 and 5) in the proposed method are absent, as well as the operation of heating with water vapor and coking vapors (No. 9 and 11). All other operations, except the third, have a shorter duration in time. As for the comparison with the prototype, which is also aimed at reducing the duration of the coking cycle, it should be noted that the prototype does not have a water removal operation, since coke is unloaded with water into the subreactor bunker, coke unloading also takes less time, all other operations durations of time correspond to the analogue.

table 2
Duration of stages and operations of the coking cycle №№st. And opera. Stages, operations Duration, hour Analogue The proposed method one 2 3 four one I Stage coking 24 6-8 2 II Stage of preparation of the reactor, including: 3 - steaming coke cake 2.5 2.5 four - cooling of coke with steam and water in the reactor 2 - 5 - removal of water from the reactor 2 - 6 - opening hatches 1,5 0.25 7 - unloading coke 5 one 8 - closing hatches 2 0.25 9 - warming up the reactor with steam 0.5 - 10 - crimping one one eleven - reactor warming with coking vapors 7 - 12 - switching the feed stream from one reactor to another 0.5 0.25 13 Duration of all preparatory operations 24.0 5.25 fourteen Coking cycle 48 11.25-13.25

Thus, the proposed method allows the processing of oil residues by delayed coking to produce distillates and shot coke without introducing expensive additives into the raw materials and at the same time shorten the coking cycle by several times.

Claims (3)

1. A method of processing oil residues by delayed coking, including the stage of coking in the reactor with the formation of shot coke and the stage of preparing the reactor for the next coking cycle, comprising steaming the coke in the reactor, cooling the coke with water, unloading it into the subreactor hopper, removing water from the subreactor hopper, pressure testing the reactor water vapor, characterized in that the coking process is carried out at a temperature of 505-530 ° C for 6-8 hours and under a pressure of not more than 0.2 MPa, and the shot coke is unloaded from the reactor they are put into the subreactor hopper at a temperature of 390-420 ° С under water vapor or inert gas pressure of at least 0.1 MPa after coke steaming in the reactor, the subreactor hopper is made with internal thermal insulation and installed hermetically with respect to the reactor, while coke is cooled by water carried out in a subreactor hopper. 2. The method according to claim 1, characterized in that the coke is steamed in the reactor for 2.5 hours with a gradual increase in the flow of water vapor from 0.5 to 10 t / h 3. The method according to claim 1, characterized in that the discharge of shot-coke into a subreactor hopper with internal thermal insulation is carried out with the upper and open lower hatches of the reactor having permanently installed remotely controlled mechanical gates.