Nitric acid production unit and system

Abstract

The utility model discloses a nitric acid production unit and system, and relates to the technical field of nitric acid production equipment. The nitric acid production unit comprises a motor, a speed change assembly, an air compressor, a tail gas expansion machine and a nitric oxide compressor. Wherein the motor drives the variable-speed assembly to rotate, the air compressor, the tail gas expander and the nitric oxide compressor are connected with the variable-speed assembly, and the variable-speed assembly drives the air compressor and the nitric oxide compressor to do compression work. According to the nitric acid production unit, equipment such as a boiler for generating steam does not need to be added, and the composition of the whole nitric acid production unit is simplified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nitric acid production equipment, in particular to a nitric acid production unit and system. BACKGROUND

[0002] The existing nitric acid device usually adopts a steam turbine for driving, and since the steam turbine needs a certain amount of steam to drive operation, a boiler needs to be added to the entire device to generate a certain amount of steam to drive the steam turbine.

[0003] When the entire unit has not started, the oxidation furnace cannot generate heat to supply the steam boiler to produce steam, so additional steam needs to be provided to drive the steam turbine when the unit starts. This not only makes the entire device more complex, but also increases a lot of large equipment. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the present application provides a nitric acid production unit and system, aiming to solve one of the technical problems in the prior art.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, the present application provides a nitric acid production unit, comprising:

[0007] a motor;

[0008] a variable speed assembly, wherein the motor drives the variable speed assembly to rotate;

[0009] an air compressor, an exhaust gas expander and an oxidized nitrogen compressor, which are connected with the variable speed assembly, and the variable speed assembly drives the air compressor and the oxidized nitrogen compressor to do compression work.

[0010] In one of the embodiments of the first aspect, the air compressor comprises at least two stages of first impellers, the oxidized nitrogen compressor comprises at least one stage of second impellers, and the exhaust gas expander comprises at least two stages of third impellers.

[0011] In one of the embodiments of the first aspect, the variable speed assembly comprises a first gearbox, the input end of the first gearbox is connected with the output end of the motor through a shaft coupling, and the air compressor, the exhaust gas expander and the oxidized nitrogen compressor are connected with the output end of the first gearbox.

[0012] In one of the embodiments of the first aspect, the first gearbox comprises a first input shaft, a first transmission shaft and at least two first output shafts, the first input shaft and the output end of the motor are connected through a shaft coupling, the at least two first output shafts are respectively connected with the first transmission shaft, the first transmission shaft is also connected with the first input shaft, and any two of the first impeller, the second impeller and the third impeller are respectively connected with one of the first output shafts.

[0013] In one of the embodiments of the first aspect, the transmission assembly comprises a second gearbox and a third gearbox, the input end of the second gearbox and the output end of the motor are connected through a shaft coupling, the third gearbox, the air compressor and the nitrogen oxide compressor are respectively connected with the output end of the second gearbox, and the tail gas expander is connected with the output end of the third gearbox.

[0014] In one of the embodiments of the first aspect, the second gearbox comprises a second input shaft, a second transmission shaft and two second output shafts, the second input shaft and the output end of the motor are connected through a shaft coupling, the three second output shafts are respectively connected with the second transmission shaft, the second transmission shaft is also connected with the second input shaft, and any two of the first impeller and the second impeller are respectively connected with one of the second output shafts.

[0015] In one of the embodiments of the first aspect, the third gearbox comprises a third input shaft, a third transmission shaft and at least one third output shaft, the third input shaft and the second input shaft are connected through a shaft coupling, the at least one third output shaft is respectively connected with the third transmission shaft, the third transmission shaft is also connected with the third input shaft, and any two of the third impellers are respectively connected with one of the third output shafts.

[0016] In one of the embodiments of the first aspect, the rated rotating speed of the motor is not less than 3000 rpm.

[0017] In one of the embodiments of the first aspect, the air compressor and the nitrogen oxide compressor are both centrifugal compressors, and the tail gas expander is a centripetal or axial flow expander.

[0018] In the second aspect, the embodiments of the present application further provide a nitric acid production system, comprising:

[0019] The nitric acid production unit in any of the above embodiments;

[0020] An oxidation furnace connected with the air compressor;

[0021] A heat exchanger connected with the nitrogen oxide compressor and the oxidation furnace;

[0022] an absorption tower, which is connected to the nitric oxide compressor and the tail gas expander.

[0023] Compared with the prior art, the application has the beneficial effects that the application provides a nitric acid production unit, which comprises a motor, a variable speed assembly, an air compressor, a tail gas expander and a nitric oxide compressor. The motor drives the variable speed assembly to rotate, and the air compressor, the tail gas expander and the nitric oxide compressor are connected to the variable speed assembly, respectively. The variable speed assembly drives the air compressor and the nitric oxide compressor to do compression work. In the application, the motor replaces the steam turbine in the related art. In this way, during the start-up stage of the nitric acid production system, the nitric acid production unit drives the air compressor, the nitric oxide compressor and the expander by the motor, without the need to increase a boiler and other devices for generating steam, thereby simplifying the composition of the entire nitric acid production unit. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0025] Figure 1 Fig. 1 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the application;

[0026] Figure 2 Fig. 2 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the application;

[0027] Figure 3 Fig. 3 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the application;

[0028] Figure 4 Fig. 4 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the application;

[0029] Figure 5 Fig. 5 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the application;

[0030] Figure 6 Fig. 6 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the application;

[0031] Figure 7 Fig. 7 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the application;

[0032] Figure 8 Fig. 8 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the application;

[0033] Figure 9 Fig. 9 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the present application;

[0034] Figure 10 Fig. 10 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the present application;

[0035] Figure 11 Fig. 11 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the present application;

[0036] Figure 12 Fig. 12 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the present application;

[0037] Figure 13 Fig. 13 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the present application;

[0038] Figure 14 Fig. 14 shows a structural schematic diagram of a nitric acid production unit in some embodiments of the present application; Figure 15 Fig. 15 shows a structural schematic diagram of a nitric acid production system in some embodiments of the present application.

[0039] Main element symbol explanation: 1000 - nitric acid production system; 100 - nitric acid production unit; 110 - motor; 120 - first impeller; 130 - second impeller; 140 - third impeller; 1511 - first input shaft; 1512 - first transmission shaft; 1513 - first output shaft; 151 - first gearbox; 1521 - second input shaft; 1522 - second transmission shaft; 1523 - second output shaft; 152 - second gearbox; 1531 - third input shaft; 1532 - third transmission shaft; 1533 - third output shaft; 153 - third gearbox; 200 - oxidation furnace; 300 - heat exchanger; 400 - absorption tower. DETAILED DESCRIPTION

[0040] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for explanation of the present application, and cannot be understood as a limitation of the present application.

[0041] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0042] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0043] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be broadly understood, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0045] As Figure 1 As shown in the drawings, the embodiment of the present application provides a nitric acid production unit 100, which is mainly used for producing nitric acid. The nitric acid production unit 100 comprises a motor 110, a variable speed assembly, an air compressor, an exhaust gas expander and a nitrogen oxide compressor.

[0046] The motor 110 drives the variable speed assembly to rotate, the gear box serves as the basis for connecting various functional modules, and the output shaft of the motor 110 is connected to the variable speed assembly through a shaft coupling.

[0047] The air compressor, the tail gas expander and the nitrogen oxide compressor are respectively connected to the variable speed assembly, and the variable speed assembly drives the air compressor and the nitrogen oxide compressor to perform compression work. In the present application, the motor 110 replaces the steam turbine in the related art. In this way, in the start-up stage of the nitric acid production system 1000, the nitric acid production unit 100 drives the air compressor, the nitrogen oxide compressor and the tail gas expander through the motor 110. Instead of the working mode in the related art in which steam needs to be additionally provided to drive the steam turbine, and then the steam turbine drives the air compressor, the nitrogen oxide compressor and the expander. Therefore, it is not necessary to increase the boiler and other equipment for generating steam, and the composition of the entire nitric acid production unit 100 is simplified.

[0048] In one embodiment, the tail gas expander supplies mechanical work to the air compressor and the nitrogen oxide compressor through direct output, thereby reducing the power consumption of the motor 110 and improving the operating efficiency of the entire unit.

[0049] In addition, the steam turbine is driven by steam, and a steam source must be provided. Compared with the steam turbine, the motor 110 only needs to be connected to a power source, and the application range of the motor 110 is wider.

[0050] In some embodiments, as shown in Figures 1 to 8 the air compressor includes at least two stages of first impellers 120, the nitrogen oxide compressor includes at least one stage of second impellers 130, and the tail gas expander includes at least two stages of third impellers 140.

[0051] The first impellers 120, the second impellers 130 and the third impellers 140 are not coaxial with the motor 110, so that the rotational speed of each impeller is not limited by the rotational speed of the motor 110, and a higher required working speed can be obtained according to the gear box variable speed ratio design, and the operating condition range of the unit is wider.

[0052] In some embodiments, as shown in Figures 1 to 4 the variable speed assembly includes a first gear box 151, the input end of the first gear box 151 and the output end of the motor 110 are connected through a shaft coupling, and the air compressor, the tail gas expander and the nitrogen oxide compressor are respectively connected to the output end of the first gear box 151.

[0053] The output end of the motor 110 and the first input shaft 1511 of the first gear box 151 are connected together through a shaft coupling, so that the power output by the motor 110 is transmitted to the first transmission shaft 1512 of the first gear box 151, and then the power output by the motor 110 is transmitted to each first output shaft 1513 in the first gear box 151 which cooperates with the first output shaft 1513.

[0054] In some embodiments, the first gearbox 151 comprises a first input shaft 1511, a first transmission shaft 1512, and at least two first output shafts 1513, the first input shaft 1511 is connected to the output end of the motor 110 through a shaft coupling, the at least two first output shafts 1513 are respectively connected to the first transmission shaft 1512, the first transmission shaft 1512 is further connected to the first input shaft 1511, and any two of the first impeller 120, the second impeller 130, and the third impeller 140 are respectively connected to one first output shaft 1513.

[0055] It should be noted that the number of the first output shafts 1513 is two, three, or four. Figures 1 to 3 In some embodiments, the number of the first output shafts 1513 is three, Figures 5 to 6 In some embodiments, the number of the first output shafts 1513 is two, Figure 4 In some embodiments, the number of the first output shafts 1513 is four.

[0056] For example, as shown in FIG. 1, the first input shaft 1511 is connected to the first output shaft 1513 through a shaft coupling. Figure 1 As shown in FIG. 1, the first input shaft 1511 is connected to the other three first output shafts 1513, and a gear is mounted or integrated on each of the first output shafts 1513, the first input shaft 1511 and the three first output shafts 1513 form a gear transmission pair to form the first gearbox 151.

[0057] In some embodiments, one of the first output shafts 1513 is used as the rotor of the first impeller 120, one of the first output shafts 1513 is used as the rotor of the second impeller 130, and the remaining one of the first output shafts 1513 is used as the rotor of the third impeller 140, without the need for additional shaft couplings, the entire unit is very compact and highly integrated.

[0058] It should be understood that the number of the first output shafts 1513 is related to the total number of the first impeller 120, the second impeller 130, and the third impeller 140. For example, the number of the first impeller 120 is three, the number of the second impeller 130 is three, and the number of the third impeller 140 is three, one first output shaft 1513 is connected to one or two impellers, and therefore, at least five first output shafts 1513 are required.

[0059] It should be noted that the specific position of each impeller is not particularly limited.

[0060] For example, as shown in FIG. 1, the uppermost first output shaft 1513 is connected to two third impellers 140 and one second impeller 130, the middle first output shaft 1513 is connected to two first impellers 120, and the lowermost first output shaft 1513 is connected to two second impellers 130. Figure 1 For example, as shown in FIG. 1, the uppermost first output shaft 1513 is connected to two third impellers 140 and one second impeller 130, the middle first output shaft 1513 is connected to two first impellers 120, and the lowermost first output shaft 1513 is connected to two second impellers 130.

[0061] Figure 2 ​As shown, the uppermost first output shaft 1513 is connected with one first impeller 120 and one third impeller 140, the middle first output shaft 1513 is connected with one third impeller 140 and one second impeller 130, and the lowermost first output shaft 1513 is connected with one third impeller 140 and one second impeller 130.

[0062] As shown, the uppermost first output shaft 1513 is connected with one first impeller 120 and one third impeller 140, the middle first output shaft 1513 is connected with one third impeller 140 and one second impeller 130, and the lowermost first output shaft 1513 is connected with one third impeller 140 and one second impeller 130. Figure 3 As shown, the uppermost first output shaft 1513 is connected with one first impeller 120 and one third impeller 140, the middle first output shaft 1513 is connected with one third impeller 140 and one second impeller 130, and the lowermost first output shaft 1513 is connected with one third impeller 140 and one second impeller 130.

[0063] As shown, the uppermost first output shaft 1513 is connected with one first impeller 120 and one third impeller 140, the middle first output shaft 1513 is connected with one third impeller 140 and one second impeller 130, and the lowermost first output shaft 1513 is connected with one third impeller 140 and one second impeller 130. Figure 4 As shown, the uppermost first output shaft 1513 is connected with one first impeller 120 and one third impeller 140, the middle first output shaft 1513 is connected with one third impeller 140 and one second impeller 130, and the lowermost first output shaft 1513 is connected with one third impeller 140 and one second impeller 130.

[0064] In addition, since each first output shaft 1513 is not connected in series but in the form of gear pair cooperation, similar to a parallel structure, the torsional vibration problem of the rotor system is greatly reduced, and the stability and reliability of the entire rotor system are greatly guaranteed and improved.

[0065] At the same time, since the motor 110 is used as the main drive, the problem of needing external equipment to provide additional steam to drive the steam turbine during the starting stage of the existing nitric acid production unit 100 is solved, and a compact nitric acid production unit 100 is formed, and the structure is more compact and the integrity is stronger, thereby greatly improving the operation stability and reliability of the unit.

[0066] In the case where the number of first output shafts 1513 is two, as shown, Figure 5 As shown, the uppermost first output shaft 1513 is connected with one first impeller 120 and one third impeller 140, the middle first output shaft 1513 is connected with one third impeller 140 and one second impeller 130, and the lowermost first output shaft 1513 is connected with one third impeller 140 and one second impeller 130.

[0067] As shown, the uppermost first output shaft 1513 is connected with one first impeller 120 and one third impeller 140, the middle first output shaft 1513 is connected with one third impeller 140 and one second impeller 130, and the lowermost first output shaft 1513 is connected with one third impeller 140 and one second impeller 130. Figure 6 As shown, the uppermost first output shaft 1513 is connected with one first impeller 120 and one third impeller 140, the middle first output shaft 1513 is connected with one third impeller 140 and one second impeller 130, and the lowermost first output shaft 1513 is connected with one third impeller 140 and one second impeller 130.

[0068] In some embodiments, the variable speed assembly includes a second gearbox 152 and a third gearbox 153, an input end of the second gearbox 152 is connected with the output end of the motor 110 through a shaft coupling, the third gearbox 153, the air compressor and the nitrogen oxide compressor are respectively connected with an output end of the second gearbox 152, and the exhaust gas expander is connected with an output end of the third gearbox 153.

[0069] In one embodiment, as shown in FIG. 2, the second gearbox 152 includes a second input shaft 1521, a second transmission shaft 1522 and three second output shafts 1523, the second input shaft 1521 is connected with the output end of the motor 110 through a shaft coupling, the three second output shafts 1523 are respectively connected with the second transmission shaft 1522, the second transmission shaft 1522 is further connected with the second input shaft 1521, and any two of the first impeller 120 and the second impeller 130 are respectively connected with one second output shaft 1523. Figures 7 to 14 In one embodiment, as shown in FIG. 3, the third gearbox 153 includes a third input shaft 1531, a third transmission shaft 1532 and at least one third output shaft 1533, the third input shaft 1531 is connected with the third input shaft 1531 through a shaft coupling, the at least one third output shaft 1533 is respectively connected with the third transmission shaft 1532, the third transmission shaft 1532 is further connected with the third input shaft 1531, and any two of the third impeller 140 are respectively connected with one third output shaft 1533.

[0070] Figures 7 to 14 In one embodiment, as shown in FIG. 3, the third gearbox 153 includes a third input shaft 1531, a third transmission shaft 1532 and at least one third output shaft 1533, the third input shaft 1531 is connected with the third input shaft 1531 through a shaft coupling, the at least one third output shaft 1533 is respectively connected with the third transmission shaft 1532, the third transmission shaft 1532 is further connected with the third input shaft 1531, and any two of the third impeller 140 are respectively connected with one third output shaft 1533.

[0071] It should be noted that the gear ratio (the ratio of the number of teeth of the large gear to the small gear) of the gear pairs of the second gearbox 152 and the third gearbox 153 can be set according to the rotor speed required by the actual air compressor, nitrogen oxide compressor and exhaust gas expander connected therewith.

[0072] As shown in FIG. 2, the second transmission shaft 1522 is respectively matched with the other three second output shafts 1523 (a gear is also mounted or integrated on each of the two output shafts), the second input shaft 1521 and the three second output shafts 1523 form a gear transmission pair to form the second gearbox 152; the third transmission shaft 1532 is matched with one third output shaft 1533 (a gear is also mounted or integrated on each of the two output shafts), the third input shaft 1531 and one third output shaft 1533 form a gear transmission pair to form the third gearbox 153. Figure 7

[0073] ​​The second gearbox 152 includes a second input shaft 1521 and at least two second output shafts 1523, wherein the two second output shafts 1523 serve as the rotors of the air compressor and the nitrogen oxide compressor, respectively. The first impeller 120 and the second impeller 130 are respectively mounted on the respective second output shafts 1523; correspondingly, the third impeller 140 is mounted on the third output shaft 1533. No additional coupling is required for connection, and the entire unit is very compact and highly integrated.

[0074] The remaining second input shaft 1521 of the second gearbox 152 is connected to the third input shaft 1531 of the third gearbox 153 via a coupling. This means that the motor 110, the second input shaft 1521 of the second gearbox 152, and the third input shaft 1531 of the third gearbox 153 are connected together via two couplings.

[0075] It should be noted that there are no particular restrictions on the specific position of each impeller for the second gearbox 152.

[0076] For example, such as Figure 7 As shown, one second output shaft 1523 of the second gearbox 152 is connected to a first impeller 120 and a second impeller 130, and the other second output shaft 1523 of the second gearbox 152 is connected to a first impeller 120 and a second impeller 130.

[0077] For example, such as Figure 8 As shown, one second output shaft 1523 of the second gearbox 152 is connected to two first impellers 120, and the other second output shaft 1523 of the second gearbox 152 is connected to two second impellers 130.

[0078] It should be understood that the number of second output shafts 1523 is related to the total number of first impellers 120 and second impellers 130. For example, if there are two first impellers 120 and one second impeller 130, and one second output shaft 1523 connects one or two impellers, then at least two second output shafts 1523 are required.

[0079] In the third gearbox 153, the third output shaft 1533 and the third input shaft 1531 cooperate with each other (a gear is also installed or integrated on the third input shaft 1531). The third output shaft 1533 and the third input shaft 1531 form a gear transmission pair and form the third gearbox 153.

[0080] For example, such as Figures 7 to 14As shown, the third gearbox 153 includes one third output shaft 1533 and one third input shaft 1531, wherein the third transmission shaft 1532 serves as the rotor of the third impeller 140, the third impeller 140 is installed on the third output shaft 1533 without the need of additional coupling for connection, and the whole unit is very compact and highly integrated.

[0081] It should be understood that the number of third output shafts 1533 is related to the total number of third impellers 140. For example, as shown in the figure, the number of third impellers 140 is 3, and one third output shaft 1533 is connected with one or two impellers, therefore, at least two third output shafts 1533 are needed. Figure 7

[0082] In some embodiments, the rated speed of the motor 110 is not less than 3000 rpm.

[0083] It should be noted that the design speed of the first impeller 120, the second impeller 130 and the third impeller 140 is not less than 3000 rpm, and the motor 110 of the present application is a common three-phase asynchronous motor 110 or a permanent magnet variable frequency synchronous motor 110.

[0084] When the permanent magnet synchronous variable frequency motor 110 is used, the rated frequency of the permanent magnet synchronous variable frequency motor 110 can not be limited to 50 Hz (i.e. the rated frequency of the high-speed motor 110 can be higher than 50 Hz, the synchronous speed can also be higher than 3000 rpm, and the high-speed motor 110 is generally a synchronous motor 110, and the rated speed thereof is the synchronous speed, for example, a permanent magnet synchronous variable frequency high-speed motor 110 with a rated frequency of 800 Hz has a rated speed of 48000 rpm, and the frequency of the motor 110 can be changed within the rated speed range through a frequency converter to achieve stepless speed regulation).

[0085] In some embodiments, the air compressor and the nitrogen oxide compressor are both centrifugal compressors; the tail gas expander is a centripetal or axial flow expander. According to the structure, they all belong to rotary turbines, which produce centrifugal force or centripetal force through the rotation of the impeller to realize work.

[0086] As shown in the figure, the present application also provides a nitric acid production system 1000, which includes the nitric acid production unit 100, the oxidation furnace 200, the heat exchanger 300 and the absorption tower 400 in any of the above embodiments. Figure 15 Among them, the oxidation furnace 200 is connected with the air compressor; the heat exchanger 300 is connected with the nitrogen oxide compressor and the oxidation furnace 200, and the absorption tower 400 is connected with the nitrogen oxide compressor and the tail gas expander.

[0087]

[0088] ​​The motor 110 replaces the steam turbine in the related art. In the start-up stage of the nitric acid production system 1000, the nitric acid production unit 100 drives the air compressor, the nitric oxide compressor and the tail gas expander through the motor 110. The working mode of the related art is replaced, i.e., the steam turbine is driven by the additional steam, and then the steam turbine drives the air compressor, the nitric oxide compressor and the expander. Therefore, the boiler and other devices for generating steam are not needed, and the composition of the entire nitric acid production system 1000 is simplified.

[0089] In addition, when the oxidation furnace 200 can generate heat to supply the boiler to generate steam, the steam enters the tail gas expander to do work and is discharged into the atmosphere. The motor 110 is mainly used to drive the air compressor and the nitric oxide compressor to compress the gas. The work done by the tail gas expander is used to supplement the power required by the air compressor and the nitric oxide compressor to compress the gas, so as to reduce the power consumption of the motor 110 and improve the operation efficiency of the entire unit. The motor 110 and the tail gas expander are equivalent to power sources that do work and are delivered to the air compressor and the nitric oxide compressor to provide energy for compressing the gas.

[0090] The entire device process is relatively simple and efficient. The heat exchanger 300 can use the boiler to replace and generate steam to drive the tail gas expander. In particular, in the start-up stage of the entire device, the steam is not needed to be additionally obtained through other methods to be provided to the steam turbine for driving.

[0091] In some embodiments, the nitric acid production process of the nitric acid production system 1000 of the present application is as follows:

[0092] The normal-pressure air is input into the air compressor, the motor 110 drives the air compressor to do compression work, and the air compressor outputs compressed air;

[0093] The compressed air is mixed with ammonia gas, and enters the oxidation furnace 200 to react to obtain nitric oxide gas;

[0094] The nitric oxide gas after the heat exchanger is input into the heat exchanger 300 for cooling treatment;

[0095] The cooled nitric oxide gas enters the nitric oxide compressor, the motor 110 drives the nitric oxide compressor to do compression work, and the nitric oxide gas is compressed;

[0096] The compressed nitric oxide gas enters the absorption tower 400 to generate nitric acid.

[0097] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0098] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A nitric acid production train, characterized in that, include: Electric motor; A transmission assembly, wherein the motor drives the transmission assembly to rotate, the transmission assembly includes a first gearbox, and the input end of the first gearbox and the output end of the motor are connected by a coupling; An air compressor, an exhaust gas expander, and a nitrogen oxide compressor are respectively connected to the output end of the first gearbox. The transmission assembly drives the air compressor and the nitrogen oxide compressor to perform compression work. The air compressor includes at least two stages of first impellers, the nitrogen oxide compressor includes at least one stage of second impellers, and the exhaust gas expander includes at least two stages of third impellers.

2. The nitric acid production train of claim 1, wherein The first gearbox includes: a first input shaft, a first drive shaft, and at least two first output shafts. The first input shaft is connected to the output end of the motor via a coupling. The at least two first output shafts are respectively connected to the first drive shaft. The first drive shaft is also connected to the first input shaft. Any two of the first impeller, the second impeller, and the third impeller are respectively connected to one of the first output shafts.

3. The nitric acid production train of claim 1, wherein, The transmission assembly includes a second gearbox and a third gearbox. The input end of the second gearbox and the output end of the motor are connected by a coupling. The third gearbox, the air compressor, and the nitrogen oxide compressor are respectively connected to the output end of the second gearbox. The exhaust gas expander is connected to the output end of the third gearbox.

4. The nitric acid production train of claim 3, wherein The second gearbox includes: a second input shaft, a second drive shaft, and two second output shafts. The second input shaft is connected to the output end of the motor via a coupling. The three second output shafts are respectively connected to the second drive shaft. The second drive shaft is also connected to the second input shaft. Any two of the first impeller and the second impeller are respectively connected to one of the second output shafts.

5. The nitric acid production train of claim 4, wherein, The third gearbox includes: a third input shaft, a third drive shaft, and at least one third output shaft. The third input shaft and the second input shaft are connected by a coupling. The at least one third output shaft is connected to the third drive shaft. The third drive shaft is also connected to the third input shaft. Any two of the third impellers are connected to one of the third output shafts.

6. The nitric acid production train according to any one of claims 1 to 5, characterized in that, The rated speed of the motor is not less than 3000 rpm.

7. The nitric acid production train according to any one of claims 1 to 5, characterized in that Both the air compressor and the nitrogen oxide compressor are centrifugal compressors; the exhaust gas expander is a centripetal or axial flow expander.

8. A nitric acid production system characterized by comprising: include: The nitric acid production unit according to any one of claims 1 to 7; An oxidation furnace is connected to the air compressor; A heat exchanger connects the nitrogen oxide compressor and the oxidation furnace; An absorption tower, which is connected to the nitrogen oxide compressor and the exhaust gas expander.

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