Synthesis gas compressor system and surge control method for synthetic ammonia plant

Abstract

The present application relates to the technical field of synthesis gas compressors, and discloses a synthesis gas compressor system and surge control method for a synthetic ammonia plant. A second-stage separator is connected to the air inlet of the high-pressure compressor to merge the low-pressure compressor pipeline and a group of pipelines of the high-pressure compressor, and an anti-surge valve is provided between the first-stage separator and the second cooler to form a first anti-surge circuit. The two circuits share the same air inlet, outlet, and anti-surge valve, allowing the gas flow and pressure in the two pipelines to remain within a certain range. Thus, the first anti-surge valve is controlled by comprehensively considering the first-stage inlet pressure, the first-stage outlet pressure, the first-stage inlet flow, the circulating gas inlet pressure, the second-stage outlet pressure, and the second-stage inlet flow, thereby achieving the anti-surge function of the two circuits. This saves one anti-surge pipeline, thus saving one anti-surge valve, and reducing the anti-surge cost of the compressor system.

Description

Technical Field

[0001] The present application relates to the technical field of synthesis gas compressors, and in particular to a synthesis gas compressor system and a surge control method for a synthetic ammonia plant. Background Art

[0002] The ammonia synthesis process consists primarily of gasification, shift conversion, purification, and ammonia synthesis. During the production process, materials are cooled and condensed based on the temperature requirements of the process stream through methods such as ambient temperature circulating cooling water, heat exchange between materials, and ammonia evaporative cooling and cryogenic cooling, achieving separation, purification, and lowering of the temperature.

[0003] Existing ammonia synthesis plants use centrifugal syngas compressors, typically driven by variable-frequency motors or steam turbines. Conventional two-cylinder compressors are equipped with three anti-surge control systems: one anti-surge line for the low-pressure cylinder and two for the high-pressure cylinder. However, these three anti-surge lines require at least three surge valves, which increases the processor's difficulty controlling multiple surge valves and leads to high manufacturing and operating costs. Summary of the Invention

[0004] In view of the above situation, the embodiments of the present application provide a synthesis gas compressor system and surge control method for a synthetic ammonia plant, aiming to solve the above problems or at least partially solve the above problems.

[0005] In a first aspect, an embodiment of the present application provides a synthesis gas compressor system for a synthetic ammonia plant, comprising:

[0006] A two-stage compressor unit, comprising a low-pressure compressor and a high-pressure compressor;

[0007] A first anti-surge circuit, wherein the first anti-surge circuit comprises:

[0008] a first-stage separator, wherein a first end of the first-stage separator is connected to the fresh gas pipeline, and a second end of the first-stage separator is connected to the air inlet of the low-pressure compressor;

[0009] a first cooler, wherein the first end of the first separator section is connected to the air outlet of the low-pressure compressor;

[0010] a two-stage separator, wherein a first end of the two-stage separator is connected to the second end of the first cooler, and a second end of the two-stage separator is connected to the first air inlet of the high-pressure compressor;

[0011] a second cooler, wherein a first end of the second cooler is connected to the air outlet of the high-pressure compressor and an output manifold;

[0012] a first anti-surge valve connected between the third end of the first-stage separator and the second end of the second cooler;

[0013] A second anti-surge circuit, wherein the second anti-surge circuit comprises:

[0014] a three-stage separator, wherein a first end of the three-stage separator is connected to the circulating gas pipeline, and a second end of the three-stage separator is connected to the second air inlet of the high-pressure compressor;

[0015] a second anti-surge valve connected between the third end of the three-stage separator and the second end of the second cooler;

[0016] A processor is electrically connected to the first anti-surge valve and the second anti-surge valve, and is used to control the operation of the first anti-surge valve according to the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow, the circulating gas inlet pressure, the second stage outlet pressure and the second stage inlet flow, and to control the operation of the second anti-surge valve according to the system output flow, the circulating gas inlet pressure and the system output pressure.

[0017] Furthermore, the system includes:

[0018] a sensor group electrically connected to the processor, the sensor group being configured to detect the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow rate, the circulating gas inlet pressure, the second stage outlet pressure, the second stage inlet flow rate, and the system output pressure;

[0019] The sensor group includes at least one of a temperature sensor, a flow sensor, a liquid level sensor and a pressure sensor.

[0020] Furthermore, the system includes:

[0021] a first-stage filter connected between the second end of the first-stage separator and the air inlet of the low-pressure compressor;

[0022] a second-stage filter connected between the second end of the second-stage separator and the first air inlet of the high-pressure compressor;

[0023] The three-stage filter is connected between the second end of the three-stage separator and the second air inlet of the high-pressure compressor.

[0024] Furthermore, the system includes:

[0025] a flow valve electrically connected to the processor, wherein the flow valve is configured to adjust the flow of the fluid in the first anti-surge circuit and the second anti-surge circuit;

[0026] An exhaust device is connected to the air outlet of the high-pressure compressor and the output main pipe through an exhaust pipeline. A horizontal control valve and a high-pressure control valve are provided on the exhaust pipeline. The horizontal control valve and the high-pressure control valve are electrically connected to the processor respectively.

[0027] In a second aspect, an embodiment of the present application further provides a surge control method, comprising:

[0028] Obtaining the first-stage inlet pressure, first-stage outlet pressure, and first-stage inlet flow of the low-pressure compressor, the second-stage outlet pressure and second-stage inlet flow of the high-pressure compressor, the circulating gas inlet pressure of the three-stage separator, and the system output flow and system output pressure at the output manifold;

[0029] controlling the operation of the first anti-surge valve according to the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow rate, the circulating gas inlet pressure, the second stage outlet pressure, and the second stage inlet flow rate;

[0030] The operation of the second anti-surge valve is controlled according to the system output flow, the circulating gas inlet pressure and the system output pressure.

[0031] Furthermore, controlling the operation of the first anti-surge valve according to the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow, the circulating gas inlet pressure, the second stage outlet pressure, and the second stage inlet flow includes:

[0032] generating a surge curve according to the compression values ​​of the inlet pressure of the section and the outlet pressure of the section, and the inlet flow rate of the section;

[0033] generating a second-stage surge curve according to the compression value of the circulating gas inlet pressure and the second-stage outlet pressure, and the second-stage inlet flow rate;

[0034] Processing the first surge curve and the second surge curve to determine a first control curve of the first anti-surge loop;

[0035] The first anti-surge valve is controlled to operate according to the first control curve.

[0036] Furthermore, controlling the operation of the second anti-surge valve according to the system output flow, the circulating gas inlet pressure, and the system output pressure includes:

[0037] generating a second control curve of the second anti-surge loop according to the system output pressure, the circulating gas inlet pressure, and the system output pressure;

[0038] The second anti-surge valve is controlled to operate according to the second control curve.

[0039] Furthermore, the processing of the first surge curve and the second surge curve includes:

[0040] establishing a target coordinate system, wherein the target coordinate system includes the first surge curve and the second surge curve;

[0041] comparing a first ordinate of the first surge curve and a second ordinate of the second surge curve corresponding to the same abscissa in the target coordinate system;

[0042] If the first ordinate is greater than or equal to the second ordinate, generating an anti-surge curve according to the abscissa and the first ordinate;

[0043] If the first ordinate is smaller than the second ordinate, generating an anti-surge curve according to the abscissa and the second ordinate;

[0044] The first control curve is determined according to the anti-surge curve and a preset error offset.

[0045] Furthermore, the method further comprises:

[0046] Creating an operating point of the secondary compressor group in the target coordinate system according to the operating parameters of the secondary compressor group;

[0047] The controlling the operation of the first anti-surge valve according to the first control curve includes:

[0048] determining an opening of the first anti-surge valve according to a positional relationship between the operating point and the first control curve, and adjusting the first anti-surge valve according to the opening of the first anti-surge valve;

[0049] The controlling the second anti-surge valve to operate according to the second control curve includes:

[0050] The opening of the second anti-surge valve is determined according to the positional relationship between the operating point and the second control curve, and the second anti-surge valve is adjusted according to the opening of the second anti-surge valve.

[0051] Furthermore, the method further comprises:

[0052] Obtaining the first stage inlet temperature of the low-pressure compressor, the second stage inlet temperature and the third stage inlet temperature of the high-pressure compressor;

[0053] performing correction processing on the first control curve according to the first stage inlet temperature and the second stage inlet temperature;

[0054] The second control curve is corrected according to the three inlet temperatures.

[0055] Furthermore, obtaining the three-stage inlet temperature of the high-pressure compressor includes:

[0056] Obtaining the circulating gas inlet temperature of the three-stage separator;

[0057] The third-stage inlet temperature is determined according to the second-stage inlet temperature and the circulating gas inlet temperature.

[0058] In a third aspect, an embodiment of the present application further provides a computer-readable storage medium, which stores one or more programs. When the one or more programs are executed by an electronic device including multiple applications, the electronic device performs the steps of the above-mentioned second aspect.

[0059] At least one of the above technical solutions adopted in the embodiments of the present application can achieve the following beneficial effects: connecting the two-stage separator to the air inlet of the high-pressure compressor to merge the low-pressure compressor pipeline and a group of pipelines of the high-pressure compressor, and setting an anti-surge valve between the first-stage separator and the second cooler to form a first anti-surge circuit. The two circuits share the same air inlet, air outlet and anti-surge valve, so that the gas flow and pressure in the two pipelines are kept within a certain range. In this way, the first anti-surge valve is controlled by comprehensively considering the first-stage inlet pressure, the first-stage outlet pressure, the first-stage inlet flow, the circulating gas inlet pressure, the second-stage outlet pressure and the second-stage inlet flow, thereby realizing the anti-surge function of the two circuits. This saves one anti-surge pipeline, also saves one anti-surge valve, and reduces the anti-surge cost of the compressor system. At the same time, the second anti-surge valve is set between the three-stage separator and the second cooler. The high-pressure fluid is diverted through the second cooler and then passes through the second anti-surge valve, reducing the flow through the second anti-surge valve, alleviating the anti-surge difficulty of the second anti-surge valve, ensuring the anti-surge effect, and ensuring the safe, reliable and fast startup of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0061] Figure 1 The following is a schematic structural diagram of a synthesis gas compressor system for a synthetic ammonia plant according to an embodiment of the present application;

[0062] Figure 2 A schematic flow chart of a surge control method provided in an embodiment of the present application is shown;

[0063] Figure 3 A schematic diagram of a first control curve provided in an embodiment of the present application is shown.

[0064] Reference numerals:

[0065] 10 low-pressure compressor, 20 high-pressure compressor, 110 first-stage separator, 120 first-stage filter, 130 first cooler, 140 first anti-surge valve, 211 second-stage separator, 212 third-stage separator, 221 second-stage filter, 222 third-stage filter, 230 second cooler, 240 second anti-surge valve, 310 sensor group, 320 exhaust device. DETAILED DESCRIPTION

[0066] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0067] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and are not to be construed as limiting the present application.

[0068] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, or there may be intermediate elements. In addition, "connected" or "connected" as used herein may include wireless connection or wireless fusion. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0069] Before introducing the embodiments of the present application in detail, relevant technologies of compressors are first introduced.

[0070] A compressor compresses low-pressure gas into high-pressure gas. The ratio of the compressor's outlet pressure to its inlet pressure is called the pressure ratio. Due to the mechanical constraints of the compressor, at any operating speed, the compressor has a maximum pressure ratio, corresponding to its minimum flow rate. When the compressor's inlet / outlet pressure ratio exceeds the maximum pressure ratio, or the compressor's flow rate falls below the minimum flow rate, the compressor surges, potentially causing serious safety incidents. Therefore, compressor startup must prevent surge.

[0071] In this embodiment, a synthesis gas compressor system for a synthetic ammonia plant is provided. The synthesis gas compressor system is mainly used to compress synthesis gas, such as synthetic ammonia, synthesis gas, etc. The compressor system includes: a two-stage compressor unit, a first anti-surge circuit, a second anti-surge circuit, and a processor.

[0072] Specifically, if Figure 1 As shown, a two-stage compressor unit includes a low-pressure compressor 10 and a high-pressure compressor 20. Compared to a three-stage compressor unit, a two-stage compressor unit has relatively lower procurement, maintenance, and operating costs. Furthermore, a two-stage compressor unit generally has higher efficiency and can provide a relatively high compression ratio. The high-pressure compressor 20 is a dual-inlet compressor. One inlet of the high-pressure compressor 20 is a low-pressure side inlet, used to introduce low-pressure fresh air into the compressor. The other inlet of the high-pressure compressor 20 is a high-pressure side inlet, used to introduce high-pressure circulation into the compressor. This improves compression efficiency and performance, and reduces energy loss and heat generation during the compression process. The pipeline connecting the low-pressure compressor 10 is referred to as the first-stage pipeline, the pipeline connecting the low-pressure side of the high-pressure compressor 20 is referred to as the second-stage pipeline, and the pipeline connecting the high-pressure side of the high-pressure compressor 20 is referred to as the third-stage pipeline. Fresh gas refers to uncompressed, untreated gas entering the compressor, such as ammonia, oxygen, nitrogen, water vapor, ethylene, etc.

[0073] The first anti-surge circuit includes a first-stage separator 110, a first cooler 130, a second-stage separator 211, a second cooler 230, and a first anti-surge valve 140. The first end of the first-stage separator 110 is connected to the fresh air pipeline, and the second end of the first-stage separator 110 is connected to the air inlet of the low-pressure compressor 10. The first end of the first-stage separator 110 is connected to the air outlet of the low-pressure compressor 10. The first end of the second-stage separator 211 is connected to the second end of the first cooler 130, and the second end of the second-stage separator 211 is connected to the first air inlet of the high-pressure compressor 20. The first end of the second cooler 230 is connected to the air outlet of the high-pressure compressor 20 and the output manifold. The first anti-surge valve 140 is connected between the third end of the first-stage separator 110 and the second end of the second cooler 230. In other words, the first anti-surge circuit includes a first-stage pipeline and a second-stage pipeline.

[0074] The second anti-surge circuit includes a three-stage separator 212 and a second anti-surge valve 240. The first end of the three-stage separator 212 is connected to the circulating gas pipeline, and the second end of the three-stage separator 212 is connected to the second air inlet of the high-pressure compressor 20. The second anti-surge valve 240 is connected between the third end of the three-stage separator 212 and the second end of the second cooler 230. In other words, the second anti-surge circuit includes three pipelines.

[0075] A processor is electrically connected to the first anti-surge valve 140 and the second anti-surge valve 240. The processor is configured to generate a first-stage surge curve and a second-stage surge curve containing surge thresholds based on the first-stage inlet pressure, the first-stage outlet pressure, the first-stage inlet flow rate, the recycle gas inlet pressure, the second-stage outlet pressure, and the second-stage inlet flow rate. The processor is configured to determine a first control curve for anti-surge based on the first-stage surge curve and the second-stage surge curve. The processor controls the operation of the first anti-surge valve 140 based on the first control curve, and controls the operation of the second anti-surge valve 240 based on the system output flow rate, the recycle gas inlet pressure, and the system output pressure. The anti-surge valves are thereby used to control the fluid flow rate in the system to prevent surge.

[0076] In this embodiment, a two-stage separator is connected to the high-pressure compressor's air inlet to merge the low-pressure compressor pipeline with a group of high-pressure compressor pipelines. An anti-surge valve is installed between the first-stage separator and the second cooler to form a first anti-surge circuit. The two circuits share the same air inlet, outlet, and anti-surge valve, maintaining the gas flow and pressure in both pipelines within a certain range. This allows the first anti-surge valve to be controlled by a combination of the first-stage inlet pressure, first-stage outlet pressure, first-stage inlet flow, recycle gas inlet pressure, second-stage outlet pressure, and second-stage inlet flow, achieving dual anti-surge functionality. This eliminates one anti-surge pipeline and one anti-surge valve, reducing the anti-surge cost of the compressor system. Simultaneously, a second anti-surge valve is installed between the three-stage separator and the second cooler. High-pressure fluid is diverted by the second cooler before passing through the second anti-surge valve, reducing the flow through the second anti-surge valve and easing the anti-surge difficulty of the second anti-surge valve, ensuring effective anti-surge operation and ensuring safe, reliable, and fast startup of the compressor.

[0077] In one embodiment, if Figure 1 As shown, the synthesis gas compressor system for the synthetic ammonia plant further includes a sensor group 310 .

[0078] Specifically, the sensor group 310 is electrically connected to the processor and is configured to detect the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow, the circulating gas inlet pressure, the second stage outlet pressure, the second stage inlet flow and the system output pressure.

[0079] In this embodiment, the sensor group can be used to accurately collect the flow rate and pressure of the fluid in different pipelines, so as to calculate the surge curves of different pipelines of the compressor, thereby achieving precise control of the anti-surge valve.

[0080] In a specific application scenario, the sensor group includes at least one of a temperature sensor, a flow sensor, a liquid level sensor, and a pressure sensor.

[0081] In one embodiment, if Figure 1 As shown, the synthesis gas compressor system for the synthetic ammonia plant further includes: a first-stage filter 120 , a second-stage filter 221 and a third-stage filter 222 .

[0082] Specifically, the first-stage filter 120 is connected between the second end of the first-stage separator 110 and the air inlet of the low-pressure compressor 10. The second-stage filter 221 is connected between the second end of the second-stage separator 211 and the first air inlet of the high-pressure compressor 20. The third-stage filter 222 is connected between the second end of the third-stage separator 212 and the second air inlet of the high-pressure compressor 20.

[0083] In this embodiment, a filter is provided between each separator and the compressor, through which impurities and pollutants in the fluid in the pipeline, such as dust, oil, etc., can be filtered, thereby preventing impurities and pollutants from entering the compressor, reducing wear and damage to the compressor, extending the service life of the compressor, and reducing the frequency and cost of maintenance and cleaning.

[0084] In one embodiment, the synthesis gas compressor system for a synthetic ammonia plant further includes: a flow valve.

[0085] Specifically, the flow valve is electrically connected to the processor, and the flow valve is configured to adjust the flow of the fluid in the first anti-surge circuit and the second anti-surge circuit.

[0086] In this embodiment, appropriate flow valves are set and controlled by a processor to adjust the gas flow in the first anti-surge circuit and the second anti-surge circuit of the system, thereby preventing excessive or insufficient gas from entering the system, thereby maintaining the normal operation and performance of the system, reducing energy waste, improving the energy efficiency of the system, and preventing excessively high or low gas flow from damaging system equipment, thereby extending the service life of the equipment.

[0087] In one embodiment, if Figure 1 As shown, the synthesis gas compressor system for the synthetic ammonia unit further includes an exhaust device 320.

[0088] Specifically, the exhaust device 320 is connected to the air outlet and the output main pipe of the high-pressure compressor 20 through an exhaust pipeline. A horizontal control valve and a high-pressure control valve are provided on the exhaust pipeline. The horizontal control valve and the high-pressure control valve are electrically connected to the processor respectively.

[0089] In this embodiment, the horizontal control valve can adjust the fluid flow rate in the exhaust line as needed, while the high-pressure control valve can adjust the fluid pressure in the exhaust line as needed to ensure normal system operation. Specifically, when the fluid pressure in the system is too high, the high-pressure control valve can automatically open and drain the excess fluid until the system pressure is within a safe range.

[0090] For example, Figure 1 As shown, the syngas compressor system for an ammonia synthesis plant includes a low-pressure compressor 10 for compressing fresh gas into syngas, and a high-pressure compressor 20 for compressing recycle gas and fresh gas into syngas. The syngas produced by the high-pressure compressor 20 is fed to the ammonia synthesis system for subsequent production. Fresh gas passes through a fresh gas pipeline and is separated and purified in a first-stage separator 110. After separation and purification, it is fed through a first-stage filter 120 to the low-pressure compressor 10. The low-pressure compressor 10 performs a first-stage compression to produce primary compressed gas. This primary compressed gas is cooled by a first cooler 130 to prevent high-temperature expansion and backflow. It is then separated again by a second-stage separator 211 and fed to a second-stage filter 221 and the high-pressure compressor 20 for further compression. A portion of the high-temperature, high-pressure gas from the high-pressure zone of the high-pressure compressor 20 is cooled to a lower temperature, high-pressure gas by a second cooler 230. This gas is separated by the first-stage separator 110 and then fed back to the low-pressure compressor 10, ensuring that the pressure in the high-pressure zone of the high-pressure compressor 20 is consistent with that in the low-pressure zone of the low-pressure compressor 10. Another portion of the high-temperature, high-pressure gas from the high-pressure region of the high-pressure compressor 20 is mixed and separated with the recycle gas in the three-stage separator 212 before passing through the three-stage filter 222 and entering the high-pressure compressor 20 for compression into synthesis gas. A first anti-surge valve 140 is provided between the inlet of the low-pressure compressor 10 and the second cooler 230, and a second anti-surge valve 240 is provided between the recycle gas inlet of the high-pressure compressor 20 and the second cooler 230. During normal operation, the first and second anti-surge valves 140 and 240 are closed. If the pressure of the high-pressure compressor 20 suddenly increases, the first and / or second anti-surge valves 140 and 240 are controlled to open based on the inlet and outlet pressures. This diversion increases the flow rate in the pipelines containing the first and / or second anti-surge valves 140 and 240, thereby preventing surge.

[0091] In this embodiment, a surge control method is provided, such as Figure 2 As shown, the method is applicable to the synthesis gas compressor system in the above embodiment, and the method includes:

[0092] Step 401, obtaining the first stage inlet pressure, first stage outlet pressure, and first stage inlet flow of the low-pressure compressor, the second stage outlet pressure and second stage inlet flow of the high-pressure compressor, the circulating gas inlet pressure of the third stage separator, and the system output flow and system output pressure at the output main pipe;

[0093] Step 402, controlling the operation of the first anti-surge valve according to the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow, the circulating gas inlet pressure, the second stage outlet pressure, and the second stage inlet flow;

[0094] Step 403: Control the operation of the second anti-surge valve according to the system output flow, the circulating gas inlet pressure, and the system output pressure.

[0095] In this embodiment, sensors installed in the system collect the first-stage inlet pressure, first-stage outlet pressure, and first-stage inlet flow rate of the low-pressure compressor; the second-stage outlet pressure and second-stage inlet flow rate of the high-pressure compressor; the recycle gas inlet pressure of the third-stage separator; and the system output flow rate and system output pressure at the output manifold. The first-stage inlet pressure, first-stage outlet pressure, and first-stage inlet flow rate are used to determine the surge status of the first section of the pipeline where the low-pressure compressor resides. The recycle gas inlet pressure, second-stage outlet pressure, and second-stage inlet flow rate are used to determine the surge status of the second section of the pipeline where the high-pressure compressor resides. The surge status of both pipelines is then combined to control the opening or closing of the first anti-surge valve. This prevents surge in both sections of the pipeline using a single anti-surge valve, thereby ensuring effective anti-surge performance while saving an anti-surge pipeline and reducing the anti-surge cost of the compressor system. Furthermore, the system output flow rate, recycle gas inlet pressure, and system output pressure are used to determine the surge status of the third section of the pipeline where the high-pressure compressor resides. This information is then used to control the opening or closing of the second anti-surge valve to prevent surge in the third section of the pipeline where the high-pressure compressor resides.

[0096] In one embodiment, step 402, i.e., controlling the operation of the first anti-surge valve based on the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow rate, the recycle gas inlet pressure, the second stage outlet pressure, and the second stage inlet flow rate, specifically includes the following steps:

[0097] Step 402-1, generating a surge curve according to compression values ​​of a section of inlet pressure and a section of outlet pressure, and a section of inlet flow rate;

[0098] Step 402-2, generating a second-stage surge curve based on the compression value of the circulating gas inlet pressure and the second-stage outlet pressure, as well as the second-stage inlet flow rate;

[0099] For example, a dimensionless value corresponding to the inlet flow rate is calculated using a preset formula to facilitate comparison and normalization of data collected from different circuits, facilitating analysis and calculation. A surge curve is then generated, representing the ratio of inlet to outlet pressures versus flow rate, using the pressure ratio between inlet and outlet pressures as the ordinate and the dimensionless value corresponding to the inlet flow rate as the abscissa.

[0100] Step 402-3, processing the first surge curve and the second surge curve to determine a first control curve of the first anti-surge loop;

[0101] Step 402-4: Control the operation of the first anti-surge valve according to the first control curve.

[0102] In this embodiment, a first-stage surge curve and a second-stage surge curve are determined based on the inlet and outlet pressures and inlet flow rates of each pipeline segment. The first-stage surge curve and the second-stage surge curve are used to determine the pipeline surge conditions on the low-pressure side of the low-pressure compressor and the high-pressure compressor, respectively. The surge conditions of the two pipeline segments are combined to generate a first control curve that meets the surge requirements of both pipeline segments. The first control curve is used to control the opening or closing of the first anti-surge valve, thereby preventing and avoiding surge in the first anti-surge circuit in a timely manner, ensuring optimal system operation and improving efficiency and performance.

[0103] In one embodiment, step 402-3, i.e., processing the first-stage surge curve and the second-stage surge curve to determine the first control curve of the first anti-surge loop, specifically includes: establishing a target coordinate system including the first-stage surge curve and the second-stage surge curve; comparing the first ordinate of the first-stage surge curve and the second ordinate of the second-stage surge curve corresponding to the same abscissa in the target coordinate system; if the first ordinate is greater than or equal to the second ordinate, generating the anti-surge curve based on the abscissa and the first ordinate; if the first ordinate is less than the second ordinate, generating the anti-surge curve based on the abscissa and the second ordinate; and determining the first control curve based on the anti-surge curve and a preset error offset.

[0104] It should be noted that the points corresponding to the vertical coordinates used to generate the anti-surge curve can be located on the same surge curve or on different surge curves. For example, the vertical coordinates of two sampling points A1 and B1 on a first-segment surge curve are compared with the vertical coordinates of two sampling points A2 and B2 on a second-segment surge curve. Among them, the vertical coordinate value of A1 is greater than that of A2, and the vertical coordinate value of B2 is greater than that of B1. Then, A1 and B2 are used as references to generate the anti-surge curve.

[0105] In this embodiment, a target coordinate system is constructed that can include a single surge curve and a second surge curve. The vertical coordinate values ​​of the two surge curves corresponding to the same horizontal coordinate are compared. The larger vertical coordinate is used as the target vertical coordinate, and then offset by the safety surge margin to form an anti-surge curve. This control is based on the surge conditions of the pipeline with the larger flow rate under the same pressure ratio, ensuring that the operating points of the compressors in the two pipelines in the first anti-surge circuit are always within the anti-surge safety surge margin. This improves system efficiency and reliability, and extends the service life of the equipment.

[0106] Furthermore, considering the operational instability and overall energy efficiency of the compressor, a limited degree of surge or operational instability is tolerated during system operation. To this end, a preset error offset is determined based on the user's desired surge control accuracy. The anti-surge curve is then offset by this offset to form the final first control curve. When the system operating point reaches the first control curve, the first anti-surge valve is controlled to open. This effectively prevents and controls surge, enabling the system to better adapt to varying operating conditions and ensuring compressor efficiency and performance.

[0107] Among them, the safety surge margin refers to the degree to which the system operating point is above the surge curve in the compressor system. It represents the distance between the current operating state of the system and the surge boundary. The surge curve refers to the critical point where the system just surges under specific operating conditions (such as pressure, flow, etc.). When the system operating point exceeds the surge boundary line, the system will surge. The safety surge margin can be used to measure whether the system is safe enough at the current operating point and the stability of the system. The larger the safety surge margin, the more stable the system operation, the farther away from the surge boundary, and the higher the safety of the system. On the contrary, if the safety surge margin is small, the system operating point is very close to the surge boundary, and the system may be more likely to surge. The safety surge margin and the preset error offset can be reasonably set according to needs, and the embodiments of this application do not make specific limitations.

[0108] For example, Figure 3As shown, the surge line for the first stage of the compressor is plotted based on the first stage performance line. The ordinate of the first stage surge line is the ratio of the first stage outlet pressure to the first stage inlet pressure, Pd / Ps, and the abscissa of the first stage surge line is a dimensionless value related to the first stage flow rate, h / Ps. The surge line for the second stage of the compressor is plotted based on the second stage performance line. The ordinate of the second stage surge line is the ratio of the second stage outlet pressure to the second stage inlet pressure, Pd / Ps, and the abscissa of the second stage surge line is a dimensionless value related to the second stage flow rate. In the target coordinate system established by Pd / Ps to h / Ps, the multi-condition surge line appears as a broken line. By comparing the ordinates of the first and second stage surge lines, it is found that the ordinate value of the second stage surge line is larger at the same abscissa. Therefore, an anti-surge line is plotted based on each point on the second stage surge line, offset to the right by a certain safety margin. The anti-surge line is then offset to the left by a preset error offset to form a quick-opening line (first control line). When the actual working point of the compressor reaches the quick-opening line during operation, the first anti-surge valve is quickly opened to prevent the compressor from surging and damaging the compressor.

[0109] In one embodiment, step 403, i.e., controlling the operation of the second anti-surge valve according to the system output flow, the circulating gas inlet pressure, and the system output pressure, specifically includes the following steps:

[0110] Step 403-1, generating a second control curve of a second anti-surge loop according to the system output flow, the circulating gas inlet pressure, and the system output pressure;

[0111] Step 403-2: Control the second anti-surge valve to operate according to the second control curve.

[0112] In this embodiment, pipeline surge conditions on the high-pressure side of the high-pressure compressor are determined based on the recirculating gas inlet pressure of the three-section pipeline, the system output pressure of the compressor system, and the system output flow rate. Based on this information, a second control curve is generated that meets the surge requirements of the second anti-surge circuit. By controlling the opening or closing of the second anti-surge valve using this second control curve, surge in the second anti-surge circuit can be prevented or avoided in a timely manner, ensuring optimal system operation and improving efficiency and performance.

[0113] Based on the same principle as the first control curve, the surge curve of the second anti-surge loop is generated according to the system output flow, the circulating gas inlet pressure and the system output pressure. The vertical coordinate of the surge curve is offset by the safety surge margin to form the anti-surge curve, and the anti-surge curve is offset according to the preset error offset to form the final second control curve.

[0114] In one embodiment, the opening of the first anti-surge valve may be determined based on the positional relationship between the operating point of the two-stage compressor unit and a first control curve, and the first anti-surge valve may be adjusted based on the opening of the first anti-surge valve. The opening of the second anti-surge valve may be determined based on the positional relationship between the operating point of the two-stage compressor unit and a second control curve, and the second anti-surge valve may be adjusted based on the opening of the second anti-surge valve.

[0115] The operating point of the two-stage compressor unit can be created in the target coordinate system based on the operating parameters of the two-stage compressor unit. The operating parameters include inlet and outlet pressures, flow rates, compression ratios, power consumption, etc.

[0116] In this embodiment, as the pipe network resistance slowly increases, the compressor exhaust pressure will also slowly increase and the flow rate will decrease. At this time, the working point slowly approaches the control curve. When the working point reaches or exceeds the control curve, it is necessary to control the anti-surge valve to open and increase the flow rate in the pipeline so that the working point returns to the safe operating area to prevent surge. Specifically, the positional relationship between the working point and the control curve is used to determine the distance between the working point and the control curve, and then determine whether the compressor operating condition is far away from the control curve. The closer the working point is to the control curve, the larger the opening of the anti-surge valve is controlled, so that the opening of the anti-surge regulating valve can be minimized according to the system requirements and working conditions while ensuring the safe operation of the compressor. In this way, the anti-surge valve is controlled in a way that gradually adjusts the fluid flow in the loop, which not only reduces the vibration and impact load of the equipment, but also reduces the compression power and leakage loss of the system, so that the system operates at the optimal working point and improves the response speed and energy efficiency of the system.

[0117] In one embodiment, before step 402 or step 403, the surge control method further includes: obtaining the first stage inlet temperature of the low-pressure compressor, the second stage inlet temperature and the third stage inlet temperature of the high-pressure compressor; correcting the first control curve according to the first stage inlet temperature and the second stage inlet temperature; and correcting the second control curve according to the third stage inlet temperature.

[0118] In this embodiment, the corresponding control curves are corrected using the inlet temperature, thereby fully considering the differences in fluid pressure under different temperature conditions, so that the control curves can better fit the actual system operating conditions, thereby achieving more accurate anti-surge valve control and improving the system anti-surge effect.

[0119] In one embodiment, due to the presence of mixed gases within the high-pressure compressor, it is difficult to accurately collect the temperature at the compressor's third stage inlet. Therefore, the compressor's third stage inlet temperature can be calculated based on the compressor's second stage inlet temperature and the recycle gas inlet temperature, allowing the second control curve to be corrected using the third stage inlet temperature.

[0120] It should be noted that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0121] In one embodiment of the present application, a surge control device is provided. The surge control device corresponds one-to-one to the surge control method in the above embodiment, and will not be described in detail here.

[0122] An embodiment of the present application also proposes a computer-readable storage medium, which stores one or more programs, and the one or more programs include instructions. When the instructions are executed by an electronic device including multiple application programs, the electronic device can execute the surge control method provided by multiple embodiments of the present application.

[0123] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0124] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0125] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0126] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0127] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0128] Memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

[0129] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0130] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0131] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0132] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A synthesis gas compressor system for a synthetic ammonia plant, characterized in that: include: A two-stage compressor unit, comprising a low-pressure compressor and a high-pressure compressor; A first anti-surge circuit, wherein the first anti-surge circuit comprises: a first-stage separator, wherein a first end of the first-stage separator is connected to the fresh gas pipeline, and a second end of the first-stage separator is connected to the air inlet of the low-pressure compressor; a first cooler, wherein the first end of the first separator section is connected to the air outlet of the low-pressure compressor; a two-stage separator, wherein a first end of the two-stage separator is connected to the second end of the first cooler, and a second end of the two-stage separator is connected to the first air inlet of the high-pressure compressor; a second cooler, wherein a first end of the second cooler is connected to the air outlet of the high-pressure compressor and an output manifold; a first anti-surge valve connected between the third end of the first-stage separator and the second end of the second cooler; A second anti-surge circuit, wherein the second anti-surge circuit comprises: a three-stage separator, wherein a first end of the three-stage separator is connected to the circulating gas pipeline, and a second end of the three-stage separator is connected to the second air inlet of the high-pressure compressor; a second anti-surge valve connected between the third end of the three-stage separator and the second end of the second cooler; A processor is electrically connected to the first anti-surge valve and the second anti-surge valve, and is used to control the operation of the first anti-surge valve according to the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow, the circulating gas inlet pressure, the second stage outlet pressure and the second stage inlet flow, and to control the operation of the second anti-surge valve according to the system output flow, the circulating gas inlet pressure and the system output pressure.

2. The system according to claim 1, wherein: The system comprises: a sensor group electrically connected to the processor, the sensor group being configured to detect the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow rate, the circulating gas inlet pressure, the second stage outlet pressure, the second stage inlet flow rate, and the system output pressure; The sensor group includes at least one of a temperature sensor, a flow sensor, a liquid level sensor and a pressure sensor.

3. The system according to claim 1, wherein: The system comprises: a first-stage filter connected between the second end of the first-stage separator and the air inlet of the low-pressure compressor; a second-stage filter connected between the second end of the second-stage separator and the first air inlet of the high-pressure compressor; The three-stage filter is connected between the second end of the three-stage separator and the second air inlet of the high-pressure compressor.

4. The system according to claim 1, wherein: The system comprises: a flow valve electrically connected to the processor, wherein the flow valve is configured to adjust the flow of the fluid in the first anti-surge circuit and the second anti-surge circuit; An exhaust device is connected to the air outlet of the high-pressure compressor and the output main pipe through an exhaust pipeline. A horizontal control valve and a high-pressure control valve are provided on the exhaust pipeline. The horizontal control valve and the high-pressure control valve are electrically connected to the processor respectively.

5. A method for controlling surge of a synthesis gas compressor system for a synthetic ammonia plant according to any one of claims 1 to 4, characterized in that: The method comprises: Obtaining the first-stage inlet pressure, first-stage outlet pressure, and first-stage inlet flow of the low-pressure compressor, the second-stage outlet pressure and second-stage inlet flow of the high-pressure compressor, the circulating gas inlet pressure of the three-stage separator, and the system output flow and system output pressure at the output manifold of the compressor system; controlling the operation of the first anti-surge valve according to the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow rate, the circulating gas inlet pressure, the second stage outlet pressure, and the second stage inlet flow rate; The operation of the second anti-surge valve is controlled according to the system output flow, the circulating gas inlet pressure and the system output pressure.

6. The method according to claim 5, characterized in that The controlling the operation of the first anti-surge valve according to the first stage inlet pressure, the first stage outlet pressure, the first stage inlet flow, the circulating gas inlet pressure, the second stage outlet pressure, and the second stage inlet flow comprises: generating a surge curve according to the compression values ​​of the inlet pressure of the section and the outlet pressure of the section, and the inlet flow rate of the section; generating a second-stage surge curve according to the compression value of the circulating gas inlet pressure and the second-stage outlet pressure, and the second-stage inlet flow rate; Processing the first surge curve and the second surge curve to determine a first control curve of the first anti-surge loop; controlling the operation of the first anti-surge valve according to the first control curve; The controlling the operation of the second anti-surge valve according to the system output flow, the circulating gas inlet pressure, and the system output pressure includes: generating a second control curve of the second anti-surge loop according to the system output flow, the circulating gas inlet pressure, and the system output pressure; The second anti-surge valve is controlled to operate according to the second control curve.

7. The method according to claim 6, characterized in that The processing of the first surge curve and the second surge curve includes: establishing a target coordinate system, wherein the target coordinate system includes the first surge curve and the second surge curve; comparing a first ordinate of the first surge curve and a second ordinate of the second surge curve corresponding to the same abscissa in the target coordinate system; If the first ordinate is greater than or equal to the second ordinate, generating an anti-surge curve according to the abscissa and the first ordinate; If the first ordinate is smaller than the second ordinate, generating an anti-surge curve according to the abscissa and the second ordinate; The first control curve is determined according to the anti-surge curve and a preset error offset.

8. The method according to claim 7, characterized in that The method further comprises: Creating an operating point of the secondary compressor group in the target coordinate system according to the operating parameters of the secondary compressor group; The controlling the operation of the first anti-surge valve according to the first control curve includes: determining an opening of the first anti-surge valve according to a positional relationship between the operating point and the first control curve, and adjusting the first anti-surge valve according to the opening of the first anti-surge valve; The controlling the second anti-surge valve to operate according to the second control curve includes: The opening of the second anti-surge valve is determined according to the positional relationship between the operating point and the second control curve, and the second anti-surge valve is adjusted according to the opening of the second anti-surge valve.

9. The method according to claim 6, characterized in that The method further comprises: Obtaining the first stage inlet temperature of the low-pressure compressor, the second stage inlet temperature and the third stage inlet temperature of the high-pressure compressor; performing correction processing on the first control curve according to the first stage inlet temperature and the second stage inlet temperature; The second control curve is corrected according to the three inlet temperatures.

10. The method according to claim 9, characterized in that The obtaining of the three-stage inlet temperature of the high-pressure compressor includes: Obtaining the circulating gas inlet temperature of the three-stage separator; The third-stage inlet temperature is determined according to the second-stage inlet temperature and the circulating gas inlet temperature.

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