RU2408653C1 - Procedure for processing oil residues - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention refers to procedure for processing oil residues. The procedure consists in heating raw material in a coil of a furnace to temperature 455-500°C, in supply of heat treated raw material into a reactor under pressure, and in withdrawal of gas-steam and liquid phase correspondingly from the top and bottom of the reactor into a rectifying column for separation. Also, heat treated raw material is supplied into the reactor tangentially above the level of liquid phase in the reactor where liquid phase occupies 50-75% of reactor height. Height of the above said level is set by control over withdrawal of liquid phase, while pressure is set by control over withdrawal of gas-steam phase.

EFFECT: production of target products of specified quality from oil residues.

2 cl, 8 ex, 1 tbl, 1 dwg

Description

The invention relates to oil refining, in particular to a method for processing oil residues.

A known method of processing oil residues by visbreaking, including heating the feed to 450-490 ° C in a furnace coil, feeding heated feed to a remote reaction chamber, outputting the visbreaking products via a slurry pipeline to a distillation column with the distillate, gas oil fractions and residue separated. A feature of the method is the creation of a pressure differential between the reaction chamber and the subsequent equipment using a pressure reducing valve or valve installed on the helmet pipeline. The method allows you to adjust the quality indicator-color of gas oil fractions. (Pat. RF No. 2339675, C10G 9/00, op. 27.11.2008).

The disadvantage of this method is that the reducing valve on the helmet pipe is installed on a two-phase flow (gas-vapor mixture and liquid phase), which creates a pulsating, unstable mode of processes occurring both in the reactor and in the column, accompanied by emissions of the reaction mass from the reactor into the column and deterioration in the quality of gas oil fractions (color) and bottoms (mechanical impurities).

There is a method of processing oil residues in a thermal cracking unit, according to which heavy oil residues are heated in a preheater to a temperature of 100-200 ° C, then activated with compressed air, air is separated in a gas separator, and again heated in a tube furnace to a temperature of 380-410 ° C and fed to a remote thermal cracking reactor, from where gas-steam cracking products are removed from the top of the reactor, and liquid from the bottom, and sent to a distillation column for separation into fractions. (Pat. RF No. 2232789, C10G 9/00, op. 20.07.2003).

The disadvantage of this method is that the quality control of the final products: fuel oil or bitumen has an increased complexity and instability due to the three-stage technological scheme of the installation, restrictions on achieving a predetermined heating temperature of activated raw materials due to coke formation in the volume of the liquid phase. In addition, the use of direct contact of air and oil within the flash point of raw materials when using a gas separator reduces the safety of the process.

The technical result to which the invention is directed is to improve the control of the reactor operating mode to obtain products of a given quality and to increase the level of process safety.

To achieve the specified technical result in a method for processing oil residues, including heating the feed in the furnace coil to a temperature of 455-500 ° C, supplying the heat-treated feed to the reactor under pressure, withdrawing the gas-vapor and liquid phases, respectively, from the top and bottom of the reactor to the distillation column for separation, according to the invention, the supply of heat-treated raw materials to the reactor is carried out tangentially above the level of the liquid phase in the reactor, comprising 50-75% of the height of the reactor, and the height of the aforementioned level is set pu the regulation of the output of the liquid phase, and pressure - by regulating the output of the gas-vapor phase.

It is advisable to control the output of the gas-vapor and liquid phases by means of control valves.

When the flow from the furnace into the reactor is tangentially introduced above the level of the liquid phase (50-75% of the height of the reactor) due to centrifugal and gravitational forces, a more accelerated and clear separation of the reaction mass into gas-vapor and liquid phases occurs in the free separating space (50-25% of height) of the reactor. Separate withdrawal of single-phase flows through the helmets to the column through the control valves allows you to safely maintain the specified pressure and level of the liquid phase in the reactor and the rectification process in the column, thereby ensuring the desired quality of the remainder of the processing process: viscosity and content of solids (insoluble in alcohol-toluene mixture - GOST 10585-75). The coincidence of the direction of movement of the liquid phase (from top to bottom) with the action of gravitational forces eliminates stagnant zones in the reactor and, therefore, reduces the process of coke formation in the volume of the liquid phase and slows down the growth rate of solids (insoluble substances in the alcohol-toluene mixture when obtaining a residue with a reduced viscosity).

The attached drawing shows a diagram of a plant for processing oil residues by visbreaking.

The visbreaking unit includes a feed line 1, a furnace for heating the feed to a predetermined temperature 2, a line for tangentially introducing heat-treated feed 3 into the reactor, reactor 4, a separation space 5 of the reactor, a liquid phase 6, a transfer pipeline for a gas-vapor mixture 7, a pressure-pressure valve for a gas-vapor phase 8 a distillation column 9, a transfer pipeline of a liquid phase 10, a control valve 11 of the liquid phase level, a cold stream input line 12, an output line for thermal decomposition products of the raw materials from the column: 13 - gas, gasoline, water; 14 - light gas oil, 15 - heavy gas oil; 16 - VAT residue; acute irrigation (gasoline) supply line 17, chilled circulation irrigation supply line 18, water vapor supply line 19, stripping column 20, visbreaking residue line 21 (+ 180 ° C.), gas oil line 22, cold stream refrigerator 23, refrigerator 24 residue (+ 180 ° С) visbreaking, line 25 of the cooling agent (oil products, water).

The proposed method works as follows.

Raw materials - oil residue 1, preheated in heat exchangers 23, 24, enters the furnace 2, where it is heated by burning fuel to a temperature of 455-500 ° C. The heat-treated raw material 3 is introduced tangentially into the reactor 4 above the level of the liquid phase in the free separation space 5, where the reaction mass is separated into gas-vapor and liquid phases, the latter settles down, maintaining a given level of the liquid phase 6. The gas-vapor phase from the top of the reactor 4 through the transfer pipeline 7 enters through the control valve 8 into the distillation column 9 for separation by components. The control valve 8 maintains a pressure in the reactor in the range of 0.6-1.0 MPa. The liquid phase, descending into the lower part of the reactor, undergoes further thermal degradation and is fed through the transfer pipe 10 through a control valve 11, which maintains an optimal level of 50-75% of the height of the reactor, into column 9 for separation. To stop the process of cracking the feedstock and coking the pipeline and the column, a “cold stream” 12 is introduced into the stream at the inlet of the column 12. In the column 9 during the rectification process the products are obtained: gas, gasoline, water 13, light 14 and heavy 15 gas oils, bottoms 16. To ensure the rectification process, acute irrigation (gasoline) 17, circulating irrigation (gas oil) 18 and water vapor 19 are fed to column 9. To control the flash point of boiler fuel, light gas oil 14 is withdrawn through a stripping column 20, to the bottom of which water vapor 19 is supplied When using light and heavy gas oils as raw materials for secondary processes (hydrotreating, catalytic cracking, hydrocracking), these products are removed from the unit separately, and the quality is controlled by selecting the fractional composition, changing the column operating mode by known methods.

Upon receipt of the residue (+ 180 ° C) of visbreaking 21 with a minimum viscosity, the light and heavy gas oil streams are combined into a total visbreaking gas oil stream 22, which is mixed with bottoms residue 16 and removed from the unit as boiler fuel through the terminal cooler 24.

The table shows the results of the pilot visbreaking installation, according to the diagram shown in the figure according to the proposed method (examples 1-6) and the prototype (examples 7, 8), on the remainder of West Siberian oil.

Visbreaking residue analyzes were carried out according to GOST 10585-75 for boiler fuel, in particular, conditional viscosity at 80 ° C - according to GOST 6258-52, the content of solids or insoluble substances in the alcohol-toluene mixture according to GOST 40585-75. The color of gas oil was determined on a CNT calorimeter according to GOST 20284-74, the rest of the analyzes were carried out according to the methods adopted in oil refining.

The data (examples 1-6) show that the proposed method allows to reduce the viscosity of the residue (+ 180 ° C) visbreaking by increasing the pressure (temperature) and maintaining the optimal level of the liquid phase in the reactor. At the same time, the residues obtained (+ 180 ° C) in terms of quality: viscosity (WU _{80 ° C} ) and mechanical impurities meet the requirements of the standard for boiler fuel M 100, where WU _{80 ° C} no more than 16; solids not more than 1.5%.

In the prototype (examples 7, 8), the control of the reactor operation mode has significant limitations on the heating temperature of activated raw materials due to the onset of coke formation in the volume of the liquid phase, determined by the growth of solids, therefore, the viscosity of the residue (+ 180 ° C) does not meet the permissible limits (19-25 > 16), despite the maximum filling level of the reactor.

Table Performance indicators of the pilot visbreaking unit No. p.p. Technological mode in the reactor Conventional viscosity of the residue (+ 180 ° С), VU _{80 ° C} The content of solids in the residue (+ 180 ° C) visbreaking,% ** Temperature ° C Pressure, MPa The height of the liquid phase,% one 430 0.6 75 fifteen 0.12 2 430 0.6 fifty 16 0.1 3 445 0.8 75 fourteen 0.3 four 445 0.8 fifty 14.5 0.25 5 460 one 75 13 0.4 6 460 one fifty 13.5 0.35 7 * 380 0.6 75 25 0.4 8* 400 one 75 19 0.8 * - Prototype. ** - The content of substances insoluble in the alcohol-toluene mixture according to GOST 10585-75 is not more than 1.5% (the method for determining the content is according to GOST 6370-83).

Thus, the proposed method, due to improved control over the operation of the reactor, makes it possible to obtain a marketable product, boiler fuel, from oil residues that meets the requirements of the standard and, in addition, increase the level of safety during operation of the installation.

Claims (2)

1. A method of processing oil residues, including heating the feed in the furnace coil to a temperature of 455-500 ° C, supplying the heat-treated feed to the reactor under pressure, withdrawing the gas-vapor and liquid phases from the top and bottom of the reactor, respectively, to a distillation column, characterized in that the heat-treated raw materials are fed into the reactor tangentially above the level of the liquid phase in the reactor, comprising 50-75% of the height of the reactor, the height of the aforementioned level being established by controlling the output of the liquid phase, and the pressure by put We regulate the output of the gas-vapor phase. 2. The method according to claim 1, characterized in that the output of the gas-vapor and liquid phases from the reactor is carried out using control valves.

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