CN111472984A

CN111472984A - Centrifugal compressor for high-pressure hydrocracking unit

Info

Publication number: CN111472984A
Application number: CN202010434644.7A
Authority: CN
Inventors: 孙忠良
Original assignee: Shenyang Site Machinery Manufacturing Co ltd
Current assignee: Shenyang Site Machinery Manufacturing Co ltd
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2020-07-31

Abstract

A centrifugal compressor for a high-pressure hydrocracking unit is characterized in that: the device comprises a rotor set, a stator set, a support bearing, a thrust bearing and a dry gas seal, wherein (1) impellers of the rotor set are in a sequential structure, the number of the impellers is 8, and a high-efficiency ternary backward-bending closed structure is adopted; (2) the shell of the stator group is connected with the left end cover and the right end cover by adopting a snap ring structure; (3) the support bearing adopts a tilting pad bearing; (4) the thrust bearing adopts a Kingsburley structure. The compressor of the invention is particularly suitable for the technical requirements of high-pressure hydrocracking process of petrochemical enterprises. All technical parameters of the product are related according to the technological parameters of users, and the product is popular with the users.

Description

Centrifugal compressor for high-pressure hydrocracking unit

Technical Field

The invention relates to the technical field of high-pressure hydrocracking devices in petrochemical industry, in particular to a centrifugal compressor for a hydrocracking process device, which can produce high-quality reforming raw materials with high potential content of aromatic hydrocarbon to the maximum extent so as to further prepare BTX light aromatic hydrocarbon or high-octane component.

Background

Hydrocracking is one of the main processes for deep processing of heavy distillate oil, which is not only an important means for producing light oil products in the oil refining industry, but also becomes a key technology of petrochemical enterprises, and plays an irreplaceable role in other processes. Hydrocracking is an important means for mass production of high-quality middle distillate (jet fuel, diesel oil and the like) and adjustment of oil product structure. Moreover, it is the only important means for directly preparing low-sulfur and low-aromatic clean fuel while lightening. Hydrocracking does not need raw material pretreatment, and VGO with high sulfur content can be directly processed. The hydrocracking tail oil can be used as a high-quality feed for preparing ethylene and can also be used as a low-sulfur catalytic cracking raw material. When different catalysts are matched and combined, the method is a key technology for producing high-grade lubricant base stock meeting the API. The clean diesel oil product can be prepared by hydrogenation modification technologies such as aromatic hydrocarbon ring opening and deep desulfurization and dearomatization for secondary conversion oil products such as catalytic cracking diesel oil and coking diesel oil.

Hydrocracking is an improvement of catalytic cracking technology. The catalytic cracking is carried out under the hydrogen condition, so that the dehydrogenation condensation reaction generated during the catalytic cracking can be inhibited, and the generation of coke is avoided. The operating conditions are 6.5-13.5 MPa of pressure and 340-420 ℃, high-grade products without olefin can be obtained, and the liquid yield can reach more than 100% (because hydrogen is added into oil molecules). It is a process in petrochemical industry, i.e. at higher pressure and temperature in the petroleum refining process, the hydrogen gas makes the heavy oil produce hydrogenation, cracking and isomerization reactions under the action of catalyst, and then the heavy oil is converted into light oil (gasoline, kerosene, diesel oil or raw material for preparing olefin by catalytic cracking and cracking). It is different from catalytic cracking in that the catalytic cracking reaction is accompanied by a hydrogenation reaction of hydrocarbons. Hydrocracking is essentially the organic combination of hydrogenation and catalytic cracking processes, and can enable heavy oil products to generate light oil products such as gasoline, kerosene and diesel oil through catalytic cracking reaction.

The hydrocracking device is a main means for processing heavy oil, under the action of catalyst and hydrogen gas the large molecule is cracked into small molecule, the atmospheric residuum can be mostly converted into gasoline, diesel oil fraction and liquefied gas, at the same time the impurities of sulfur and nitrogen can be removed, and it is characterized by that the quality of gasoline and diesel oil product is higher than that of catalytic cracking, and it contains no olefin and the property of the produced oil product is stable.

Disclosure of Invention

The invention aims to provide a centrifugal compressor suitable for a high-pressure hydrocracking device, which can provide a gas power source with stable pressure and temperature for a production process according to the parameter requirements of a high-pressure hydrocracking process.

The centrifugal compressor for the hydrocracking unit is characterized in that: including rotor group, stator group, support bearing, thrust bearing, dry gas seal, wherein:

(1) the impellers of the rotor set are in a sequential structure, the number of the impellers is 8, and a high-efficiency ternary backward bending type closed structure is adopted;

(2) the shell of the stator group is connected with the left end cover and the right end cover by adopting a snap ring structure;

(3) the support bearing adopts a tilting pad bearing;

(4) the thrust bearing adopts a Kingsburley structure.

The rotor set of the compressor comprises a main shaft, an impeller, a spacer bush, a balance disc, a lock nut and a thrust disc. The impeller adopts the structure of arranging in proper order, and the balance disk is installed at the rearmost part of impeller, and impeller and balance disk are installed and are fixed through two lock nuts on the main shaft, constitute the rotor of this compressor jointly with some other little parts. The number of the impellers of the compressor rotor is 8, the impellers adopt efficient ternary backward-bending type closed impellers, the front four impellers on the rotor are identical in structure, and the rear four impellers are identical in structure. The diameter of the impeller is 400-600 mm.

The multistage impellers with the same diameter are adopted, so that the design and production cost of the compressor is reduced and the production period of equipment is shortened on the premise of realizing the pressure required by the circulating power required by the high-pressure hydrocracking process. The method organically combines theoretical research, practical production and user requirements, and explores a new direction for industrial popularization of research and development results.

The stator of the compressor includes a casing, end caps, partitions, seals and related components.

The shell of the compressor is connected with the left end cover and the right end cover by adopting a snap ring structure, and the structure can meet the strength requirement of the 600 model high-pressure hydrocracking compressor, which is different from the traditional vertically split compressor.

The partition plate in the stator group of the compressor is an important part forming a gas passage of the compressor, the diffuser of the compressor adopts a vane diffuser, and the vane diffuser can enable gas to smoothly pass through the diffuser, so that the phenomenon that the gas generates turbulence in the diffuser and the efficiency of the compressor is influenced is prevented.

The front four impellers of the compressor rotor have the same form, the rear four impellers have the same form, the air outlet angles of the blades of the vane diffuser in the stator group are different according to the different angles of the impellers, and the different air outlet angles of the vane diffuser can effectively improve the pneumatic efficiency of the compressor.

The shaft end of the compressor is sealed by dry gas at the inlet, so that zero leakage of process gas is ensured when the compressor operates, and safe and stable operation of the compressor is ensured.

Drawings

Fig. 1 is a main sectional view of a compressor in a centrifugal compressor according to the present invention, in which: stator group 1, rotor group 2, support bearing 3, thrust bearing 4, drive end dry gas seal 5, non-drive end dry gas seal 6.

Fig. 2 is a view of the rotor of the compressor in the centrifugal compressor according to the invention, in which: the main shaft 21, the impeller 22, the impeller 23, the spacer 24, the balance disc 25, the lock nut 26, the thrust disc 27 and the thrust disc lock nut 28.

FIG. 3 is a view of a diaphragm assembly of the compressor of the centrifugal compressor of the present invention, in which: a diaphragm 11 and diffuser vanes 12.

Fig. 4 is a schematic view of a snap ring structure of a compressor in a centrifugal compressor according to the present invention, wherein: barrel 13, end cover 14, snap ring 15, locking ring 16.

Detailed Description

The centrifugal compressor will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1, the centrifugal compressor includes a stator assembly 1, a rotor assembly 2, a support bearing 3, a thrust bearing 4, a drive-end dry gas seal 5, and a non-drive-end dry gas seal 6. The above components are orderly arranged together according to the relative position of the main sectional view shown in fig. 1 to form the body of the centrifugal compressor.

Fig. 2 is a rotor diagram of the compressor. The thrust disc comprises a main shaft 21, an impeller 22, an impeller 23, a spacer bush 24, a balance disc 25, a lock nut 26, a thrust disc 27 and a thrust disc lock nut 28. The four impellers 22 and the four impellers 23 are sequentially arranged on the main shaft, the balance disc 25 is arranged behind the last impeller, the impellers and the balance disc are fixed in position through the lock nuts 26, and the thrust disc 27 and the thrust disc lock nuts 28 are arranged in the position shown in figure 2, so that a rotor set of the compressor is formed.

Fig. 3 is a view of a diaphragm assembly of a compressor in a centrifugal compressor, which mainly includes a diaphragm 11 and diffuser blades 12. The diffuser vanes 12 are not identical in the angle of deflection of the vanes depending on the impeller. The pneumatic efficiency is guaranteed to be increased.

Fig. 4 is a schematic view of a snap ring structure of the compressor. The schematic diagram includes a cylinder 13, an end cap 14, a snap ring 15 and a locking ring 16. The compressor head 14 is secured to the shell 13 using a snap ring 15 and a locking ring 16. The structure can meet the strength requirements of the end cover and the cylinder body of the high-pressure hydrogenation compressor, and compared with the conventional bolt handle, the safety of the bolt handle is greatly improved.

Claims

1. A centrifugal compressor for a high-pressure hydrocracking unit is characterized in that: comprises a rotor set, a stator set, a supporting bearing, a thrust bearing and a dry gas seal, wherein,

(3) the support bearing adopts a tilting pad bearing;

(4) the thrust bearing adopts a Kingsburley structure.

2. The centrifugal compressor for a high pressure hydrocracking apparatus as set forth in claim 1, wherein the front four impellers of said rotor are identical in structure and the rear four impellers are identical in structure. The diameters of the impellers are all 600 mm.