Steam supply system for aromatics production

Abstract

The present invention relates to the technical field of petrochemical engineering, and specifically to a steam supply system for aromatics production, which includes a first steam main pipeline and a second steam main pipeline; the first steam main pipeline is connected to an extraction unit heat exchanger through an extraction unit steam supply pipeline; the second steam main pipeline is connected to a main steam supply pipeline, and the main steam supply pipeline supplies steam to an isomerization reaction unit compressor and a disproportionation reaction unit reactor through an isomerization reaction unit steam supply pipeline and a disproportionation reaction unit steam supply pipeline respectively. The main steam supply pipeline upstream of the isomerization reaction unit steam supply pipeline and the disproportionation reaction unit steam supply pipeline is connected to the extraction unit steam supply pipeline through a cross-line. By adding a cross-line and connecting the main steam supply pipeline to the extraction unit steam supply pipeline through the cross-line, the efficiency of steam supply is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical engineering, and specifically provides a steam supply system for aromatics production. Background Art

[0002] Aromatics generally refer to hydrocarbons containing benzene rings and aromatic ring structures in their molecules. They are a type of closed-chain compound with a basic benzene ring structure. Aromatics include a benzene derivative, "p-xylene", which is one of the xylene isomers, and the remaining isomers include o-xylene and m-xylene.

[0003] In the production process of aromatics, steps such as fractionation, isomerization, adsorption, extraction, and disproportionation are usually required. In almost every link of the entire process flow, steam is needed. How to efficiently supply steam to each reaction unit is a problem to be solved in aromatics production. The existing steam supply process generally uses two steam supply lines. The first line supplies steam to the compressor of the isomerization reaction unit, the heat exchanger of the adsorption and xylene fractionation unit, the reactor of the adsorption and xylene fractionation unit, and the reactor of the disproportionation fractionation unit; the other line supplies steam to the heat exchanger of the disproportionation fractionation unit and the heat exchanger of the extraction unit. The entire steam supply process has the defects of being unreasonable and inefficient. Summary of the Invention

[0004] In view of the defects of the prior art, the present invention provides a steam supply system for aromatics production, which adds a cross-line to connect the steam supply main pipe to the steam supply pipeline of the extraction unit through the cross-line, improving the efficiency of steam supply.

[0005] To achieve the above purpose, the technical solution provided by the present invention is a steam supply system for aromatics production, which includes a first steam main pipe and a second steam main pipe; the first steam main pipe is connected to the heat exchanger of the extraction unit through the steam supply pipeline of the extraction unit; the second steam main pipe is connected to the steam supply main pipe, and the steam supply main pipe supplies steam to the compressor of the isomerization reaction unit and the reactor of the disproportionation reaction unit through the steam supply pipeline of the isomerization reaction unit and the steam supply pipeline of the disproportionation reaction unit respectively. The steam supply main pipe upstream of the steam supply pipeline of the isomerization reaction unit and the steam supply pipeline of the disproportionation reaction unit is connected to the steam supply pipeline of the extraction unit through a cross-line.

[0006] Further, a first valve is provided at a position close to the inlet end of the cross-line, a second valve is provided at the outlet end of the cross-line connected to the steam supply pipeline of the extraction unit, and a first drain valve is installed close to the second valve at the upstream of the second valve.

[0007] Further, a third valve and a second drain valve are installed at the inlet end of the steam supply pipeline of the extraction unit connected to the first steam main pipe; a fourth valve and a third drain valve are installed on the steam supply pipeline of the extraction unit close to the cross-line node position.

[0008] Further, a steam desuperheater and pressure regulator is installed on the first main steam pipeline. A conventional steam desuperheater in the prior art can be used for this steam desuperheater, which injects turbine water into the steam to achieve the purpose of reducing the temperature without reducing the pressure. The steam desuperheater is arranged downstream of the steam supply pipeline of the extraction unit, and the first main steam pipeline downstream of the steam desuperheater supplies steam to the heat exchanger of the disproportionation fractionation unit through the steam supply pipeline of the disproportionation fractionation unit.

[0009] Further, the first main steam pipeline supplies steam to the heat exchanger of the adsorption and xylene fractionation unit; the second main steam pipeline supplies steam to the reactor of the adsorption and xylene fractionation unit.

[0010] Further, a main pipeline crossover is provided between the first main steam pipeline and the second main steam pipeline, and the main pipeline crossover is arranged upstream of the adsorption and xylene fractionation unit.

[0011] Further, a fifth valve and a sixth valve are provided on the main pipeline crossover.

[0012] Preferably, the first main steam pipeline is a 3.5 MPa steam pipeline with a diameter of DN350; the second main steam pipeline is a 3.5 MPa steam pipeline with a diameter of DN250.

[0013] After the transformation of the present invention, the first main steam pipeline is led to the steam supply main pipe of the compressor K2501 in the isomerization reaction unit and connected to the steam supply pipeline of the extraction unit. After the transformation, the entire steam supply system includes: one is the first main steam pipeline, which supplies steam to the heat exchanger of the adsorption and xylene fractionation unit and the heat exchanger of the disproportionation fractionation unit after passing through the steam desuperheater and pressure regulator. Valves and drains are added at the front end of the DN350 to DN250 line before the desuperheater and pressure regulator to isolate the state.

[0014] The second is the second main steam pipeline: it supplies steam to the compressor in the isomerization reaction unit. It should be noted that at this time, the valve for the second main steam pipeline to supply steam to the heat exchanger of the adsorption and xylene fractionation unit is closed, and the steam supply for the heat exchanger of the adsorption and xylene fractionation unit follows the desuperheater and pressure regulator process of the first main steam pipeline. The second main steam pipeline also supplies steam to the heat exchanger of the extraction unit through the crossover, supplies steam to the reactor of the adsorption and xylene fractionation unit at the same time, and supplies steam to the reactor of the disproportionation reaction unit.

[0015] The beneficial effect of the present invention: By adding a crossover, the steam supply main pipe is connected to the steam supply pipeline of the extraction unit through the crossover, which improves the efficiency of steam supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the process flow diagram of the present invention;

[0017] In the figure: 1. First main steam pipeline, 1.1. Steam desuperheating and pressure-maintaining valve, 2. Second main steam pipeline, 3. Steam supply pipeline for extraction unit, 3.1. Third valve, 3.2. Second drain valve, 3.3. Fourth valve, 3.4. Third drain valve, 4. Heat exchanger for extraction unit, 5. Main steam supply header, 6. Steam supply pipeline for isomerization reaction unit, 7. Steam supply pipeline for disproportionation reaction unit, 8. Compressor for isomerization reaction unit, 9. Reactor for disproportionation reaction unit, 10. Cross line, 10.1. First valve, 10.2. Second valve, 10.3. First drain valve, 11. Steam supply pipeline for disproportionation fractionation unit, 12. Heat exchanger for disproportionation fractionation unit, 13. Heat exchanger for adsorption and xylene fractionation unit, 14. Reactor for adsorption and xylene fractionation unit, 15. Main pipeline cross line, 15.1. Fifth valve, 15.2. Sixth valve. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] A steam supply system for aromatics production, which includes a first main steam pipeline 1 and a second main steam pipeline 2; the first main steam pipeline 1 is connected to a heat exchanger 4 for the extraction unit through a steam supply pipeline 3 for the extraction unit; the second main steam pipeline 2 is connected to a main steam supply header 5, and the main steam supply header 5 supplies steam to a compressor 8 for the isomerization reaction unit and a reactor 9 for the disproportionation reaction unit through a steam supply pipeline 6 for the isomerization reaction unit and a steam supply pipeline 7 for the disproportionation reaction unit respectively. The main steam supply header 5 upstream of the steam supply pipeline 6 for the isomerization reaction unit and the steam supply pipeline 7 for the disproportionation reaction unit is connected to the heat exchanger 4 for the extraction unit through a cross line 10.

[0020] Furthermore, a first valve 10.1 is provided at a position close to the inlet end of the cross line 10, a second valve 10.2 is connected to the outlet end of the steam supply pipeline 3 for the extraction unit, and a first drain valve 10.3 is installed at a position close to the second valve 10.2 upstream of the second valve 10.2.

[0021] Furthermore, a third valve 3.1 and a second drain valve 3.2 are installed at the inlet end where the steam supply pipeline 3 for the extraction unit is connected to the first main steam pipeline 1; a fourth valve 3.3 and a third drain valve 3.4 are installed on the steam supply pipeline 3 for the extraction unit at a position close to the cross line node.

[0022] Further, a steam desuperheating and pressure maintaining device 1.1 is installed on the first main steam pipeline 1. The steam desuperheating and pressure maintaining device 1.1 is arranged downstream of the steam supply pipeline 3 of the extraction unit. The first main steam pipeline 1 downstream of the steam desuperheating and pressure maintaining device 1.1 supplies steam to the heat exchanger 12 of the disproportionation fractionation unit through the steam supply pipeline 11 of the disproportionation fractionation unit.

[0023] Further, the first main steam pipeline 1 supplies steam to the heat exchanger 13 of the adsorption and xylene fractionation unit; the second main steam pipeline 2 supplies steam to the reactor 14 of the adsorption and xylene fractionation unit.

[0024] Further, a main pipeline crossover 15 is arranged between the first main steam pipeline 1 and the second main steam pipeline 2. The main pipeline crossover 15 is arranged upstream of the adsorption and xylene fractionation unit.

[0025] Further, a fifth valve 15.1 and a sixth valve 15.2 are arranged on the main pipeline crossover 15.

[0026] Preferably, the first main steam pipeline 1 is a 3.5 MPa steam pipeline with a DN350 diameter; the second main steam pipeline 2 is a 3.5 MPa steam pipeline with a DN250 diameter.

[0027] After the transformation of the present invention, the first main steam pipeline 1 is led to the steam supply main pipe of the compressor 8 (users of K2701 / K2501) of the isomerization reaction unit and connected to the steam supply pipeline 3 of the extraction unit. After the transformation, the entire steam supply system includes:

[0028] The first stream is the first main steam pipeline 1, which supplies steam to the heat exchanger 13 (E2803 and E2814) of the adsorption and xylene fractionation unit and the heat exchanger 12 (E2502) of the disproportionation fractionation unit after passing through the steam desuperheating and pressure maintaining device 1.1. Valves and drains are added at the front end and the end of the first main steam pipeline 1 upstream of the steam desuperheating and pressure maintaining device 1.1 to isolate the state.

[0029] The second stream is the second main steam pipeline 2, which supplies steam to the compressor 8 (K2701, K2501) of the isomerization reaction unit. It should be noted that at this time, the valves (the fifth valve 15.1 and the sixth valve 15.2) of the second main steam pipeline 2 to the heat exchanger 13 (E2803, E2814) of the adsorption and xylene fractionation unit are closed, and the steam supply of the heat exchanger 13 (E2803, E2814) of the adsorption and xylene fractionation unit follows the desuperheating and non-pressure reducing process of the first main steam pipeline 1. The second main steam pipeline 2 also supplies steam to the heat exchanger 4 (E-2403, E-2406, E-2410) of the extraction unit through the crossover line 10, supplies steam to the reactor 14 (R2801A / B (intermittent), R2601 (intermittent)) of the adsorption and xylene fractionation unit at the same time, and supplies steam to the reactor 9 (R2801A / B (intermittent), R2702A / B (intermittent)) of the disproportionation reaction unit.

[0030] After the transformation, a 3.5 MPa steam user at the inlet of the compressor 8 (for users of K2701 / K2501) in the isomerization reaction unit is added, and the temperature of the 3.5 MPa steam at the compressor inlet is increased. The steam supply system for aromatics production provided by the present invention:

[0031] The change in the total steam flow rate at the inlet of the compressor in the isomerization reaction unit = the original flow rate of 23.5 t / h + the steam flow rate of the extractive unit heat exchanger of 19.8 t / h - the steam flow rate of the heat exchanger from the second main steam pipeline to the adsorption and xylene fractionation units (1.1 t / h + 6 t / h) = 36.2 t / h, which is an increase of 12.7 t / h compared to the original flow rate.

[0032] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the said element.

[0033] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made therein without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Aromatics production steam supply system, characterized by: It includes a first steam main pipeline and a second steam main pipeline; the first steam main pipeline is connected to the extraction unit heat exchanger through the extraction unit steam supply pipeline; the second steam main pipeline is connected to the steam supply main pipeline, and the steam supply main pipeline is respectively supplied to the isomerization reaction unit compressor and the disproportionation reaction unit reactor through the isomerization reaction unit steam supply pipeline and the disproportionation reaction unit steam supply pipeline. The steam supply main pipeline upstream of the isomerization reaction unit steam supply pipeline and the disproportionation reaction unit steam supply pipeline is connected to the extraction unit steam supply pipeline through a jumper line; A first valve is provided near the inlet end of the cross-line, which is connected to a second valve provided at the outlet end of the steam supply line of the extraction unit, and a first shower valve is installed upstream of the second valve near the second valve position; A third valve and a second drain valve are installed at the inlet end of the extraction unit steam supply line connected to the first steam main pipeline; a fourth valve and a third drain valve are installed on the extraction unit steam supply line near the cross-line node; A steam desuperheater without pressure reducer is installed on the first steam main pipeline, and the steam desuperheater without pressure reducer is arranged downstream of the steam supply line of the extraction unit. The first steam main pipeline downstream of the steam desuperheater without pressure reducer supplies steam to the heat exchanger of the disproportionation fractionation unit through the steam supply line of the disproportionation fractionation unit; The first steam main pipeline supplies steam to the adsorption and xylene fractionation unit heat exchanger; the second steam main pipeline supplies steam to the adsorption and xylene fractionation unit reactor; A main pipeline crossover line is provided between the first steam main pipeline and the second steam main pipeline, and the main pipeline crossover line is provided upstream of the adsorption and xylene fractionation unit; The main pipeline is provided with a fifth valve and a sixth valve across the line; The first steam main pipeline is a 3.5MPa steam pipeline; the second steam main pipeline is a 3.5MPa steam pipeline.

2. The steam supply system for aromatic hydrocarbon production according to claim 1, characterized in that: The first steam main pipeline is a DN350 3.5MPa steam pipeline; the second steam main pipeline is a DN250 3.5MPa steam pipeline.

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