Three-stage expansion and three-stage pressurization hydrogen and methane expansion compressor unit for ethylene unit
Through the design and optimization of the three-stage expansion-connected three-stage supercharged hydrogen methane expansion compressor unit, the problem of low efficiency of domestic ethylene equipment expansion unit is solved, and efficient hydrogen methane expansion and compression is achieved, with a single-stage efficiency of more than 82%, and the medium contains hydrogen The molar percentage reached 79.4%.
Patent Information
- Application Number
- CN202411349195.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-01-17
AI Technical Summary
The domestic ethylene device expansion unit has low efficiency, and no domestic manufacturer has produced efficient three-stage expansion joint three-stage supercharged hydrogen methane expansion compressor units, resulting in an imported unit dependent and efficiency less than 80%.
A three set of expansion compressor sets are designed, each set of components including the fuselage, spindle, turbine volute, booster volute, nozzle blade, expansion end impeller and compression end impeller, by optimizing the expansion end impeller The structure of the model line equation and nozzle blades realize three-stage series expansion and boosting, improving the unit efficiency.
Through reasonable matching design, the runner loss is reduced and the unit efficiency is improved. The percentage of hydrogen in the medium reaches 79.4%, the ideal enthalpy drop of each stage of expansion is about 32Kcal/kg, the impeller speed is as high as 315m/s, and the single-stage efficiency is achieved. More than 82%.
Smart Images
Figure CN119321351A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a three-stage expansion and three-stage pressurized hydrogen-methane expansion compressor unit for an ethylene device, belonging to the technical field of multi-stage expanders. Background Art
[0002] The expander of ethylene plant is a rotary machine that uses compressed gas to expand adiabatically in the expander to do work externally and consume the internal energy of the gas itself, thereby obtaining cooling capacity. Generally, it is a medium-pressure expander, which adopts multi-stage expansion and pressurization, so the stability requirements of each unit are high. So far, the expansion units of domestic ethylene plants have always relied on imports, and no one has used units produced by domestic manufacturers.
[0003] In the 1980s, due to the limitations of design optimization and processing equipment, most of the high-end expanders in China were imported from abroad, especially the low-temperature expanders used in the fields of petrochemicals, ethylene, and natural gas, which were monopolized by foreign manufacturers. In recent years, with the development of expander design and processing technology and the establishment of many large-scale processing centers in China, the gap between domestic expanders and imported expanders is gradually narrowing, and some technical levels have approached or even reached the advanced level of foreign countries. The advantages of domestic manufacturers in price, delivery time, and technical services are more prominent.
[0004] The expanders of ethylene plants are generally medium-pressure expanders, which use multi-stage expansion and pressurization, so the stability requirements of each unit are relatively high. So far, the expansion units of domestic ethylene plants have always relied on imports, and no domestic manufacturers have been used. The efficiency provided by foreign units is less than 80%. Summary of the invention
[0005] The first technical problem to be solved by the present invention is to provide a three-stage expansion and three-stage pressurized hydrogen-methane expansion compressor unit for an ethylene device with higher efficiency.
[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a three-stage expansion and three-stage boosting hydrogen methane expansion compressor unit for an ethylene device includes three sets of expansion compressor units arranged in series in sequence, each set of expansion compressor units includes a fuselage, a main shaft, a turbine volute, a boosting volute, nozzle blades, an expansion end impeller and a compression end impeller, the turbine volute is sealed and connected to the expansion end of the fuselage, the boosting volute is sealed and connected to the boosting end of the fuselage, the main shaft is rotatably installed in the fuselage through the front bearing and the rear bearing arranged at intervals, one end of the main shaft is fixedly connected to the expansion end impeller and the expansion end impeller is located in the turbine volute, and the main shaft is fixedly connected to the expansion end impeller. The other end is fixedly connected to the compression end impeller and the compression end impeller is located in the booster volute. The nozzle blades are installed in the turbine volute through the sliding disk and the positioning sleeve. The nozzle blades are evenly spaced and arranged in the peripheral area of the expansion end impeller. The three expansion compressor sets are respectively set as the first-stage expansion compressor set, the second-stage expansion compressor set and the third-stage expansion compressor set. The main shaft and the compression end impeller in the first-stage expansion compressor set, the second-stage expansion compressor set and the third-stage expansion compressor set all adopt the same structure. The expansion end impeller in the first-stage expansion compressor set adopts a profile equation of Yfw=0.0003406Z 3 +1.53,Ybw=0.0003468Z 3 +1.53; the expansion end impeller in the second stage expansion compressor unit adopts the profile equation of Yfw=0.0006002Z 3 +1.5,Ybw=0.0006103Z 3 +1.5; the expansion end impeller in the third stage expansion compressor unit adopts the profile equation of Yfw=0.0006593Z 3 +1.46,Ybw=0.0006694Z 3 +1.46; where the line equation of each expansion end impeller corresponds to an independent three-dimensional xyz coordinate system, with the rotation axis of the expansion end impeller and the airflow direction as the positive direction of the z axis, the direction of the radius r of the expansion end impeller as the positive direction of the x axis, the direction perpendicular to the x axis and the z axis and satisfying the right-hand rule as the positive direction of the y axis, the vertical intersection of the inlet point of the middle surface of the expansion end impeller blade and the z axis as the origin, Y is the coordinate value corresponding to the y axis of the coordinate axis, Z is the coordinate value corresponding to the z axis of the coordinate axis, fw is the positive pressure surface of the blade, and bw is the negative pressure surface of the blade.
[0007] In a preferred solution, the number of blade rows of the nozzle blades in the first-stage expansion-compression unit, the second-stage expansion-compression unit and the third-stage expansion-compression unit increases progressively.
[0008] A further preferred scheme is that the number of nozzle blades in the first-stage expansion compressor unit is 5 and the blade height is 4.5 mm; the number of nozzle blades in the second-stage expansion compressor unit is 5 and the blade height is 9.5 mm; the number of nozzle blades in the second-stage expansion compressor unit is 8 and the blade height is 10.5 mm.
[0009] The technical solution provided by the present invention has the following beneficial effects: through the reasonable matching design of the expansion end impeller, the flow channel loss is reduced and the unit efficiency is improved. It has been verified in practice that the present invention adopts multi-stage expansion and pressurization, and the unit is respectively connected through three-stage series expansion and three-stage series pressurization, the molar percentage of hydrogen in the medium is up to 79.4%, the ideal enthalpy drop of each stage of expansion is about 32Kcal / kg, the impeller speed linear speed is up to 315m / s (the maximum linear speed of the impeller can withstand 400m / s), and the single-stage efficiency reaches more than 82%. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 It is a typical assembly structure schematic diagram of a single expansion compressor unit in the present invention.
[0011] Figure 2 It is a schematic diagram of the nozzle blade structure in the first-stage expansion compressor unit and the second-stage expansion compressor unit in the present invention.
[0012] Figure 3 It is a schematic diagram of the nozzle blade structure in the third-stage expansion compressor unit of the present invention.
[0013] Figure 4 It is a comparative schematic diagram of the expansion end impellers in the first-stage expansion compressor unit, the second-stage expansion compressor unit and the third-stage expansion compressor unit in the present invention.
[0014] Parts markings in the figure: turbine volute 1, diffusion chamber 2, positioning sleeve 3, sliding plate 4, nozzle blade 5, positioning plate 6, expansion end wheel back seal 7, front sealing plate 8, fuselage 9, booster volute 10, rear sealing plate 11, compression end wheel back ring 12, diffusion side plate 14, first O-ring 15, compression end impeller 16, compression end wheel cover seal 17, rear sealing sleeve 18, second O-ring 19, rear bearing 20, third O-ring 21, main shaft 22, front bearing 23, fourth O-ring 24, front sealing sleeve 25, fifth O-ring 26, sixth O-ring 27, expansion end impeller 28, seventh O-ring 29. DETAILED DESCRIPTION
[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0016] like Figures 1 to 4As shown, the three-stage expansion and three-stage boosting hydrogen-methane expansion compressor unit for the ethylene device of the present invention comprises three sets of expansion compressor units arranged in series, each set of expansion compressor units comprises a fuselage 9, a main shaft 22, a turbine volute 1, a boosting volute 10, a nozzle blade 5, an expansion end impeller 28 and a compression end impeller 16, the turbine volute 1 is sealed to the expansion end of the fuselage 9, the boosting volute 10 is sealed to the boosting end of the fuselage 9, and the main shaft 22 is rotatably mounted through a front bearing 23 and a rear bearing 20 arranged at intervals. In the fuselage 9, one end of the main shaft 22 is fixedly connected to the expansion end impeller 28 so that the expansion end impeller 28 is located in the turbine volute 1, and the other end of the main shaft 22 is fixedly connected to the compression end impeller 16 so that the compression end impeller 16 is located in the booster volute 10. The nozzle blades 5 are installed in the turbine volute 1 through the sliding disk 4 and the positioning sleeve 3. The nozzle blades 5 are evenly spaced in the outer area of the expansion end impeller 28. The sliding disk 4 is mainly used to adjust the gas flow and injection angle at the nozzle blades 5. It can be implemented with reference to the prior art. The three sets of expansion compressor units are respectively set as the first-stage expansion compressor unit, the second-stage expansion compressor unit and the third-stage expansion compressor unit. The single set of expansion compressor units of the present invention has the same main structure as the prior art (see Figure 1 ), the key technical point is how to achieve three-stage series expansion and three-stage series boosting, the specific scheme is: the main shaft 22 and the compression end impeller 16 in the first-stage expansion compressor unit, the second-stage expansion compressor unit and the third-stage expansion compressor unit all adopt the same structure, and the expansion end impeller 28 in the first-stage expansion compressor unit adopts the profile equation of Yfw=0.0003406Z 3 +1.53,Ybw=0.0003468Z 3 +1.53; the expansion end impeller 28 in the second stage expansion compressor unit adopts the profile equation of Yfw=0.0006002Z 3 +1.5,Ybw=0.0006103Z 3 +1.5; the expansion end impeller 28 in the third stage expansion compressor unit adopts the profile equation of Yfw=0.0006593Z 3 +1.46,Ybw=0.0006694Z 3 +1.46; wherein, the line equation of each expansion end impeller 28 corresponds to an independent three-dimensional xyz coordinate system, with the rotation axis of the expansion end impeller 28 and the airflow direction as the positive direction of the z axis, the radius r direction of the expansion end impeller 28 as the positive direction of the x axis, the direction perpendicular to the x axis and the z axis and satisfying the right-hand rule as the positive direction of the y axis, the vertical intersection of the inlet point of the middle surface of the blade of the expansion end impeller 28 and the z axis as the origin, Y is the coordinate value corresponding to the y axis of the coordinate axis, Z is the coordinate value corresponding to the z axis of the coordinate axis, fw is the positive pressure surface of the blade, and bw is the negative pressure surface of the blade.
[0017] In a preferred solution, the number of blades of the nozzle blades 5 in the first-stage expansion compressor unit, the second-stage expansion compressor unit, and the third-stage expansion compressor unit is increasing. "The number of blades is increasing" means that the nozzle blades 5 change from a low number of blades to a high number of blades, which can be achieved by changing the number of blades, blade height and other parameters of the nozzle blades 5. A preferred solution of the present invention is that the number of blades of the nozzle blades 5 in the first-stage expansion compressor unit is 5 and the blade height is 4.5 mm; the number of blades of the nozzle blades 5 in the second-stage expansion compressor unit is 5 and the blade height is 9.5 mm; the number of blades of the nozzle blades 5 in the second-stage expansion compressor unit is 8 and the blade height is 10.5 mm.
[0018] Specific implementation cases:
[0019] The medium of this unit is mainly composed of a mixture of hydrogen and methane, with a designed mass flow rate of 3200kg / h and a maximum mass flow rate of 3520kg / h. The inlet pressure at the expansion end is 3.3167MPa(A), the outlet pressure is 0.3417MPa(A), the inlet pressure at the boosting end is 0.3067MPa(A), the outlet pressure is 0.4577MPa(A), and the isentropic enthalpy drop at the expansion end reaches 96Kcal / kg. It is designed as the three-stage series expansion and three-stage series boosting of the above scheme. After matching each stage, the final parameters are shown in the table below.
[0020] The process sections "1", "2" and "3" in the table correspond to the first-stage unit, the second-stage unit and the third-stage unit respectively.
[0021] The unit code "E-GX" series corresponds to the expansion end, and the unit code "E-GB" series corresponds to the expansion end.
[0022]
[0023] It has been verified in practice that the present invention adopts multi-stage expansion and pressurization. The units are respectively connected through three-stage series expansion and three-stage series pressurization. The molar percentage of hydrogen in the medium is as high as 79.4%. The ideal enthalpy drop of each stage of expansion is about 32 Kcal / kg. The linear speed of the impeller is as high as 315 m / s (the maximum linear speed of the impeller can withstand 400 m / s), and the single-stage efficiency reaches more than 82%.
Claims
1. A three-stage expansion and three-stage boosting hydrogen-methane expansion compressor unit for an ethylene plant, comprising three sets of expansion compressor units arranged in series, each set of expansion compressor units comprising a machine body (9), a main shaft (22), a turbine volute (1), a boosting volute (10), nozzle blades (5), an expansion end impeller (28) and a compression end impeller (16), the turbine volute (1) being sealed to the expansion end of the machine body (9), the boosting volute (10) being sealed to the boosting end of the machine body (9), the main shaft (22) being rotatably mounted in the machine body (9) through a front bearing (23) and a rear bearing (20) arranged at intervals, and the main shaft (22) being rotatably mounted in the machine body (9) through a front bearing (23) and a rear bearing (20) arranged at intervals. One end of the main shaft (22) is fixedly connected to the expansion end impeller (28) so that the expansion end impeller (28) is located in the turbine volute (1), the other end of the main shaft (22) is fixedly connected to the compression end impeller (16) so that the compression end impeller (16) is located in the booster volute (10), the nozzle blades (5) are installed in the turbine volute (1) through the sliding plate (4) and the positioning sleeve (3), the nozzle blades (5) are evenly spaced and arranged in the peripheral area of the expansion end impeller (28), and the three sets of expansion compressor sets are respectively set as the first stage expansion compressor set, the second stage expansion compressor set and the third stage expansion compressor set, characterized in that: The main shaft (22) and the compression end impeller (16) in the first stage expansion compressor unit, the second stage expansion compressor unit and the third stage expansion compressor unit all adopt the same structure. The expansion end impeller (28) in the first stage expansion compressor unit adopts a profile equation of Yfw=0.0003406Z 3 +1.53,Ybw=0.0003468Z 3 +1.53; the expansion end impeller (28) in the second stage expansion compressor unit adopts the profile equation Yfw=0.0006002Z 3 +1.5,Ybw=0.0006103Z 3 +1.5; the expansion end impeller (28) in the third stage expansion compressor unit adopts the profile equation Yfw=0.0006593Z 3 +1.46,Ybw=0.0006694Z 3 +1.46; wherein the line equation of each expansion end impeller (28) corresponds to an independent three-dimensional xyz coordinate system, the rotation axis of the expansion end impeller (28) and the direction of the airflow is the positive direction of the z axis, the radius r direction of the expansion end impeller (28) is the positive direction of the x axis, the direction perpendicular to the x axis and the z axis and satisfying the right-hand rule is the positive direction of the y axis, the vertical intersection of the inlet point of the middle surface of the blade of the expansion end impeller (28) and the z axis is the origin, Y is the coordinate value corresponding to the coordinate axis y axis, Z is the coordinate value corresponding to the coordinate axis z axis, fw is the positive pressure surface of the blade, and bw is the negative pressure surface of the blade.
2. The three-stage expansion and three-stage pressurized hydrogen-methane expansion compressor unit for an ethylene plant as claimed in claim 1, characterized in that: The number of blade grids of the nozzle blades (5) in the first-stage expansion compressor unit, the second-stage expansion compressor unit and the third-stage expansion compressor unit increases progressively.
3. The three-stage expansion and three-stage pressurized hydrogen-methane expansion compressor unit for an ethylene plant as claimed in claim 2, characterized in that: The number of the nozzle blades (5) in the first-stage expansion compressor unit is 5 and the blade height is 4.5 mm; the number of the nozzle blades (5) in the second-stage expansion compressor unit is 5 and the blade height is 9.5 mm; the number of the nozzle blades (5) in the second-stage expansion compressor unit is 8 and the blade height is 10.5 mm.