Security protection assembly and air separation device

Abstract

The utility model provides a kind of safety protection component and air separation equipment.Safety protection component includes detecting element, alarm and control module.Detecting element detects the parameter indicating the flow of cryogenic liquid pumped by inert cryogenic pump, and outputs parameter indicating signal indicating parameter.Alarm is set to send alarm signal.Control module is set to receive parameter indicating signal from detecting element, accordingly sends alarm indicating signal indicating alarm signal sent by alarm to alarm, and sends closing signal to delivery regulating valve and backflow regulating valve, and sends off signal to inert cryogenic pump.The above-mentioned safety protection component can realize effective safety protection to inert cryogenic pump.

Description

Technical Field

[0001] This utility model belongs to the field of air separation and relates to an air separation device. In particular, it relates to a safety protection component for protecting an inertial cryogenic pump that pumps cryogenic liquids. Background Technology

[0002] For air separation units, the main gaseous product is typically obtained by vaporizing a liquid pressurized by a cryogenic pump. The gas is then transported through pipelines for consumption by downstream facilities. The pressure stability of these pipelines is crucial for the downstream facilities. Excessive or insufficient pressure can cause the entire downstream facility to shut down. If the main pump fails, the standby pump must be activated to replace it; otherwise, the pipeline pressure cannot be maintained.

[0003] To maintain stable pipeline pressure, the switchover time between the main pump and the standby pump needs to be shortened. Currently, there are two main solutions. The first is that the main pump operates normally while the standby pump is in a cold standby state, i.e., static. If the main pump fails, the standby pump will automatically start and increase its speed to normal. The second is that the standby pump is in a coasting state while the main pump is operating normally; if the main pump fails, the standby pump will automatically increase its speed to normal. In the second solution, the standby pump can take over from the failed main pump more quickly, resulting in a higher success rate.

[0004] For conventional cryogenic pumps, safety protection components typically use detectors to trip the pump when the current or discharge pressure is low. However, for coasting cryogenic pumps used as backup pumps, the current and discharge pressure are quite low due to their low-speed operation, often far below the trip values ​​for normal speed. Therefore, conventional safety protection components cannot be used to achieve cavitation protection.

[0005] Therefore, a safety protection component needs to be designed to provide effective safety protection for this type of inertial cryogenic pump. Utility Model Content

[0006] The purpose of this invention is to provide a safety protection component that can effectively protect the aforementioned inertial cryogenic pump.

[0007] This invention provides a safety protection component for protecting a coasting cryogenic pump that pumps cryogenic liquids. The coasting cryogenic pump is installed in a piping system. The piping system includes a delivery pipeline that delivers the cryogenic liquid downstream via the coasting cryogenic pump and a return pipeline that extends from the delivery pipeline to a return point downstream of the coasting cryogenic pump. A delivery regulating valve is installed downstream of the return point on the delivery pipeline, and a return regulating valve is installed on the return pipeline. The safety protection component includes: a detection element configured to detect a parameter characterizing the flow rate of the cryogenic liquid pumped by the coasting cryogenic pump and output a parameter indication signal indicating the parameter; an alarm configured to send an alarm signal; and a control module configured to receive the parameter indication signal from the detection element, send an alarm indication signal to the alarm, send a closing signal to the delivery regulating valve and the return regulating valve, and send a shutdown signal to the coasting cryogenic pump.

[0008] In one embodiment, the detection element is a flow detector disposed on the delivery line. Further, the flow detector is disposed downstream of the coasting cryogenic pump on the delivery line. Further, the flow detector is disposed at a position between the coasting cryogenic pump and the reflux position on the delivery line.

[0009] In one embodiment, the sensing element is a differential pressure transmitter installed on the delivery pipeline. The control module obtains the flow rate of the cryogenic liquid pumped by the inertial cryogenic pump based on the differential pressure indication signal output by the differential pressure transmitter. Furthermore, the two ends of the differential pressure transmitter are respectively connected to the upstream and downstream positions of the delivery pipeline, immediately adjacent to the inlet and outlet of the inertial cryogenic pump.

[0010] In one embodiment, the safety protection component further includes an exhaust valve disposed on an exhaust line extending from the internal chamber of the inertial cryogenic pump. Furthermore, the control module is configured to send an opening signal to the exhaust valve based on a parameter indication signal received from a detection element.

[0011] This utility model also provides an air separation system, including an air separation unit, which includes a main pump in normal operating condition and a standby pump in coasting condition for standby. The air separation system also includes a safety protection component as described in any of the foregoing embodiments, the safety protection component being used for the standby pump. Further, the main pump and the standby pump are liquid oxygen pumps.

[0012] For coasting cryogenic pumps, the aforementioned safety protection components directly or indirectly detect the flow rate of the coasting cryogenic pump by setting up detection elements such as flow detectors or differential pressure transmitters. They are also equipped with control modules and alarms, and signal connections between various units are established. When an abnormal flow rate is detected, the coasting cryogenic pump can be automatically shut down and relevant valves closed, and an alarm can be issued. This ensures that the coasting cryogenic pump operates within its normal operating range, thus overcoming the problems that conventional safety protection components have when dealing with coasting cryogenic pump failures. In other words, the aforementioned safety protection components can provide effective safety protection for the coasting cryogenic pump, improving the reliability of the coasting cryogenic pump and the overall liquid delivery system.

[0013] By incorporating the aforementioned safety protection components, the air separation equipment can ensure the safety of the standby pump in coasting standby mode, thereby improving the success rate of pump group switching and the overall reliability of gas supply. Attached Figure Description

[0014] The advantages and spirit of this utility model can be further understood through the following detailed description and accompanying drawings.

[0015] Figure 1 This is a schematic diagram of an exemplary safety protection component according to the present invention.

[0016] Figure 2 This is a schematic diagram illustrating an exemplary safety protection component applied to an air separation system.

[0017] Figure 3 It is a schematic diagram illustrating the performance curves and efficiency curves. Detailed Implementation

[0018] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. However, it should be understood that this utility model is not limited to the embodiments described below, and the technical concept of this utility model can be implemented in combination with other known technologies or functions, or with other technologies that are the same as those known technologies.

[0019] For example, if the first feature described subsequently in the specification is formed above or on the second feature, this can include embodiments where the first and second features are formed by direct connection, or embodiments where an additional feature is formed between the first and second features, so that the first and second features are not directly connected. Furthermore, when the first element is described in a manner connected or combined with the second element, the description includes embodiments where the first and second elements are directly connected or combined with each other, as well as embodiments where one or more other intervening elements are incorporated to indirectly connect or combine the first and second elements with each other.

[0020] Slow roll refers to the pump operating at a low speed rather than being completely stopped. As mentioned earlier, the current and discharge pressure of a slow roll cryogenic pump are too low to be protected against normal cavitation. Furthermore, because the current is close to the motor's no-load current, the head of the slow roll cryogenic pump is low, and the discharge pressure is greatly affected by the suction pressure, making it difficult to define different trip values ​​for slow roll. Without protection, the cryogenic pump may be damaged by cavitation. This problem is particularly dangerous for liquid oxygen pumps. This is because if the pump continues to operate at low speed without a fresh supply of liquid oxygen (i.e., the pump's suction valve is closed), gaseous oxygen will accumulate and heat up due to the pump's rotation, potentially causing a serious accident when it reaches a certain temperature.

[0021] Therefore, a safety protection component and air separation equipment according to this utility model are designed, which can solve the problem that it is difficult for a low-speed coasting cryogenic pump to prevent safety hazards caused by cavitation or liquid supply interruption through conventional low current or low pressure protection.

[0022] Pipeline systems are also known as pipe networks. It is understood that the terms "pipeline," "pipeline," and "pipe segment" used in this text refer to the routes through which the flow is supplied, without limiting the physical form of the corresponding components. Taking "pipeline" as an example, a pipeline can refer to a segment of a complete pipeline. A pipeline can also be a combination of multiple pipelines connected sequentially. These multiple pipelines can be connected via pipe fittings or other pipeline components such as valves. The space through which the flow passes in the pipe fittings or other pipeline components can also be considered part of the pipeline.

[0023] Figure 1 A safety protection component 10 according to the present invention is shown. The safety protection component 10 can protect the coasting cryogenic pump 1 that pumps cryogenic liquid q0. The coasting cryogenic pump 1 is a pump that can deliver cryogenic liquid while in a low-speed coasting state.

[0024] An inertial cryogenic pump 1 is installed in a piping system 2. The piping system 2 includes a delivery pipeline 21 that delivers cryogenic liquid q0 downstream via the inertial cryogenic pump 1, and a return pipeline 22 that extends from the delivery pipeline 21 at a return point P1 downstream of the inertial cryogenic pump 1. A delivery regulating valve 31 is installed on the delivery pipeline 21 downstream of the return point P1. A return regulating valve 32 is installed on the return pipeline 22. The cryogenic liquid q0 is, for example, liquid oxygen.

[0025] After being pressurized by the inertial cryogenic pump 1, at least a portion of the cryogenic liquid q0 is sent downstream of the delivery pipeline 21, and depending on the circumstances, it can be returned to the storage tank 20 (described later) via the return pipeline 22.

[0026] The safety protection component 10 includes a detection element 4, an alarm 5, and a control module 6.

[0027] The detection element 4 is configured to detect the parameter m0, which characterizes the flow rate f0 of the cryogenic liquid q0 pumped by the inertial cryogenic pump 1, and output a parameter indication signal s0 indicating the parameter m0.

[0028] Alarm 5 is configured to send an alarm signal s5. Alarm 5 can be, for example, an audible or visual alarm, or it can send an error message to the central control display screen.

[0029] The control module 6 is configured to receive parameter indication signal s0 from the detection element 4, and accordingly send an alarm indication signal s7 to the alarm 5, and send a shut-off signal s21 to the delivery regulating valve 31 and the return regulating valve 32, and a shutdown signal s11 to the inertial cryogenic pump 1.

[0030] The control module 6 may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof.

[0031] Because the cryogenic liquid transported by the coasting cryogenic pump 1 is prone to evaporation, it is essential to ensure sufficient liquid flow through the pump body during coasting operation to maintain lubrication, cooling, and prevent cavitation. By incorporating the aforementioned detection element 4, alarm 5, and control module 6, and by arranging their signal connections and those of each component, automatic and timely alarms can be triggered when flow abnormalities occur, prompting the timely shutdown of the coasting cryogenic pump 1 and the closure of the delivery regulating valve 31 and the return regulating valve 32. Specifically, the detection element 4 can directly or indirectly monitor the flow rate f0 of the cryogenic liquid q0 passing through the coasting cryogenic pump 1. When an abnormal flow rate is detected, the control module 6 can automatically shut down the coasting cryogenic pump 1 and close relevant valves such as the delivery regulating valve 31 and the return regulating valve 32. Simultaneously, the alarm 5 will sound an alarm to ensure the safe operation of the coasting cryogenic pump 1. This overcomes the problem of conventional low-current or low-pressure protection used for normally operating cryogenic pumps failing under low-speed conditions.

[0032] The design of the aforementioned safety protection component 10 can effectively prevent the inertial cryogenic pump 1 from being damaged by cavitation, and can also avoid the serious safety risks caused by the accumulation of gas during idling when the liquid supply is interrupted, especially in the case of liquid oxygen pumps.

[0033] It is understandable that the signal connection shown in the diagram with dashed lines can be either a wired or wireless connection.

[0034] like Figure 1 As shown, the detection element 4 can be a flow detector 41 installed on the delivery pipeline 21. That is, the parameter m0 is the flow rate f0 of the cryogenic liquid q0 pumped by the inertial cryogenic pump 1. Figure 1 As shown, the flow detector 41 can be installed downstream of the coasting cryogenic pump 1 on the delivery pipeline 21. Specifically, the flow detector 41 can be installed between the coasting cryogenic pump 1 and the return position P1 on the delivery pipeline 21. The flow detector 41 can be, for example, a Coriolis flow meter, an electromagnetic flow meter, an ultrasonic flow meter, etc. This allows for accurate detection of the flow rate f0 at the outlet of the coasting cryogenic pump 1.

[0035] Figure 1 The differential pressure transmitter 42 is also shown. The sensing element 4 can also be as follows: Figure 1 The differential pressure transmitter 42, shown by the dashed line, is installed on the delivery pipeline 21. The control module 6 obtains the flow rate f0 of the cryogenic liquid q0 pumped by the coaster-driven cryogenic pump 1 based on the differential pressure indication signal s20 output by the differential pressure transmitter 42. Specifically, the two ends of the differential pressure transmitter 42 (i.e., the low-pressure end and the high-pressure end) can be connected to the delivery pipeline 21 at the upstream and downstream positions immediately adjacent to the inlet and outlet of the coaster-driven cryogenic pump 1, respectively. This allows for the detection of the actual operating differential pressure of the coaster-driven cryogenic pump 1. It can be understood that "immediately adjacent" here means that no other components are installed between the corresponding end of the differential pressure transmitter 42 and the inlet or outlet of the coaster-driven cryogenic pump 1.

[0036] It is important to understand that the differential pressure indication signal s20 output by the differential pressure transmitter 42 directly represents the differential pressure dP reached by the coasting cryogenic pump 1. The differential pressure dP, i.e., the head, corresponds to the flow rate f0; therefore, the flow rate f0 can be indirectly reflected by detecting the differential pressure. Specifically, this can be achieved through the performance curve C1 of the coasting cryogenic pump 1. Figure 3 As shown in the diagram, the flow rate corresponding to the head or pressure indicated by the pressure difference dP can be found through the calculation unit in control module 6. That is, the pressure difference dP is also a parameter m0 that can characterize the flow rate f0.

[0037] like Figure 1 As shown, the safety protection component 10 may further include an exhaust valve 33. The exhaust valve 33 may be installed in the exhaust pipe 23 leading from the internal chamber of the inertial cryogenic pump 1. Furthermore, the control module 6 may be configured to send an opening signal s32 to the exhaust valve 33 based on the parameter indication signal s0 received from the detection element 4. Exhausting and alarming can occur simultaneously. Thus, for example, when the control module 6 determines that a dangerous operating condition exists based on the parameter indication signal s0, such as when the flow rate f0 is outside the safe operating range and may lead to gas accumulation, in addition to performing the aforementioned shutdown and valve closing actions, it may immediately open the exhaust valve 33 to exhaust gas to the outside through the exhaust pipe 23, so as to safely discharge the gas that may have accumulated in the internal chamber of the inertial cryogenic pump 1 and prevent accidents caused by excessive gas pressure.

[0038] When using the aforementioned safety protection component 10, the flow rate f0 or differential pressure dP can be set to be between the upper and lower limits; otherwise, the inertial cryogenic pump 1 will trip. Specifically, the upper and lower limits of the flow rate f0 can be determined according to, for example... Figure 3 The efficiency curve C2 of the inertial pump 1 is shown. The setpoint can be obtained by adding a certain margin to the left and right endpoints of the efficiency curve C2. The upper and lower limits of the corresponding differential pressure dP can be calculated from the performance curve C1 using the upper and lower limits of the flow rate f0. By limiting the flow rate or differential pressure, the inertial pump 1 can be ensured to operate within its normal operating range. In the event of cavitation or liquid supply interruption, the inertial pump 1 will automatically shut down and trigger an alarm to prompt the operator to investigate. Figure 3 In the diagram, the horizontal axis of both performance curve C1 and efficiency curve C2 represents flow rate, for example, in L / min. The vertical axis of performance curve C1 represents head, for example, in meters (m). The vertical axis of efficiency curve C2 represents efficiency, for example, in percentage (%). Both performance curve C1 and efficiency curve C2 are characteristic curves of the pump, often referred to as the HQ curve and η-Q curve, respectively.

[0039] Figure 2 An air separation unit 100 to which the aforementioned safety protection component 10 can be applied is shown. The air separation unit 100 includes a main pump 72 in normal operating condition and a standby pump 71 in coasting condition for standby. The air separation unit 100 may also include the aforementioned safety protection component 10. The safety protection component 10 is used for the standby pump 71. That is, the standby pump 71 of the air separation unit 100 is the coasting cryogenic pump 1 that pumps the cryogenic liquid q0, for which the safety protection component 10 is applied.

[0040] Specifically, the main pump 72 and the standby pump 71 are liquid oxygen pumps, meaning that the cryogenic liquid q0 they pump is liquid oxygen. Considering that liquid oxygen is prone to explosion-like safety accidents when it evaporates into gaseous oxygen, the aforementioned safety protection component 10 is particularly suitable for liquid oxygen pumps.

[0041] The aforementioned safety protection component 10 provides effective safety protection for the standby pump 71 in a coasting state, ensuring its safe operation at low speeds. When the main pump 72 fails, the standby pump 71 can quickly start and take over. The switching speed is fast, the success rate is high, and the reliability is also high. This effectively improves the reliability of the gas supply.

[0042] Unless otherwise clearly indicated, each aspect or embodiment defined herein may be combined with any other aspect or embodiment. In particular, any feature indicated as preferred or advantageous may be combined with any other feature indicated as preferred or advantageous.

[0043] The embodiments described in this specification are merely preferred embodiments of the present invention. These embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of the present invention. All technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation should be within the scope of the present invention.

Claims

1. A safety protection component for protecting an inertial cryogenic pump that pumps cryogenic liquid, the inertial cryogenic pump being installed in a piping system, the piping system including a delivery pipeline that delivers the cryogenic liquid downstream via the inertial cryogenic pump and a return pipeline extending from the delivery pipeline at a return point downstream of the inertial cryogenic pump, a delivery regulating valve being installed on the delivery pipeline downstream of the return point, and a return regulating valve being installed on the return pipeline; characterized in that, The security protection components include: The detection element is configured to detect a parameter characterizing the flow rate of the cryogenic liquid pumped by the inertial cryogenic pump, and to output a parameter indication signal indicating the parameter. The alarm is configured to send an alarm signal; and The control module is configured to receive the parameter indication signal from the detection element, and accordingly send an alarm indication signal to the alarm to instruct the alarm to send an alarm signal, and send a shut-off signal to the delivery regulating valve and the return regulating valve, and a shutdown signal to the inertial cryogenic pump.

2. The safety protection component as described in claim 1, characterized in that, The detection element is a flow detector installed on the delivery pipeline.

3. The safety protection component as described in claim 2, characterized in that, The flow detector is located downstream of the coasting cryogenic pump on the delivery pipeline.

4. The safety protection component as described in claim 3, characterized in that, The flow detector is positioned on the delivery pipeline between the coasting cryogenic pump and the reflux position.

5. The safety protection component as described in claim 1, characterized in that, The detection element is a differential pressure transmitter installed on the delivery pipeline. The control module obtains the flow rate of the cryogenic liquid pumped by the inertial cryogenic pump based on the differential pressure indication signal output by the differential pressure transmitter.

6. The safety protection component as described in claim 5, characterized in that, The two ends of the differential pressure transmitter are respectively connected to the delivery pipeline at the upstream and downstream positions of the inlet and outlet of the inertial cryogenic pump.

7. The safety protection component as described in claim 1, characterized in that, The safety protection component also includes an exhaust valve, which is located on an exhaust pipe extending from the internal chamber of the inertial cryogenic pump.

8. The safety protection component as described in claim 7, characterized in that, The control module is configured to send an opening signal to the exhaust valve based on the parameter indication signal received from the detection element.

9. An air separation unit, comprising a main pump in normal operating condition and a standby pump in coasting condition for standby, characterized in that, It also includes a safety protection component as described in any one of claims 1 to 8, the safety protection component being used for the backup pump.

10. The air separation equipment as described in claim 9, characterized in that, The main pump and the standby pump are liquid oxygen pumps.

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