Compressed air and nitrogen integrated control system and control method

Abstract

The invention relates to nitrogen and compressed air switching, in particular to a compressed air and nitrogen integrated control system and method. Remote switching and confirmation between nitrogen and compressed air can be achieved, the possibility that the nitrogen and the compressed air are communicated with each other is thoroughly avoided, and the safety and efficiency of steel production are remarkably improved. Comprising a nitrogen branch used for connection between a nitrogen source and a user. The nitrogen bypass pipeline is connected with the nitrogen branch in parallel, and the nitrogen bypass manual valve is installed on the nitrogen bypass pipeline. The nitrogen emergency cut-off pipeline is connected with the nitrogen branch in parallel, and the nitrogen emergency electric valve and the nitrogen emergency check valve are installed on the nitrogen emergency cut-off pipeline in series. And a compressed air branch for connection between the compressed air source and the user. The compressed air bypass pipeline is connected with the compressed air branch in parallel, and the compressed air bypass manual valve is installed on the compressed air branch.

Description

Technical Field

[0001] The invention relates to nitrogen and compressed air switching, and in particular to a compressed air and nitrogen integrated control system and a control method. Background Art

[0002] In steel mills, switching between nitrogen and compressed air is a common process operation. In order to meet the needs of the production process, the supply of energy media must be fast, stable and safe. Depending on the different process conditions, nitrogen is sometimes required, and compressed air is sometimes required. Traditionally, this process usually requires operators to manually adjust the on-site valves or remotely control the electric valves through the central control room, and then go to the site to verify the status of the valves. This operation method not only has lags, affecting work efficiency, but also hinders the continuity and stability of the production process.

[0003] In addition, the traditional switching method cannot effectively isolate different media and there is a risk of gas cross-contamination, which may interfere with or even cause losses to related processes in steel manufacturing. The two methods currently used, manual on-site operation and on-site confirmation after remote control, cannot ensure that nitrogen and compressed air will not mix, thereby increasing uncertainty and risk in operation. Summary of the invention

[0004] The present invention aims to provide a compressed air and nitrogen integrated control system and control method to address the defects of the prior art. It provides a solution that can achieve remote switching and confirmation between nitrogen and compressed air, and completely avoids the possibility of the two gases communicating with each other, significantly improving the safety and efficiency of steel production. This solution is specially adapted to the specific needs of steel mills to better serve the special environment and technical requirements of the industry.

[0005] To achieve the above object, the present invention adopts the following technical solution, a compressed air and nitrogen integrated control system, comprising:

[0006] The nitrogen branch (P1) is used to connect the nitrogen source and the user. The branch is sequentially installed with a nitrogen manual valve a, a nitrogen check valve, a nitrogen electric valve a, a nitrogen pressure relief valve, a nitrogen electric valve b and a nitrogen manual valve b.

[0007] A nitrogen bypass pipeline (P2) is connected in parallel with the nitrogen branch line (P1). A nitrogen bypass manual valve is installed on the nitrogen bypass pipeline (P2) to provide a path for directly conveying gas.

[0008] A nitrogen emergency shut-off pipeline (P3) is connected in parallel with the nitrogen branch line (P1), and a nitrogen emergency electric valve and a nitrogen emergency check valve are installed in series on the nitrogen emergency shut-off pipeline (P3) for rapid shut-off in an emergency; and the nitrogen emergency electric valve is controlled by a remote control system.

[0009] The compressed air branch (P4) is used to connect the compressed air source and the user. The compressed air manual valve a, the compressed air check valve, the compressed air electric valve a, the compressed air pressure relief valve, the compressed air electric valve b, and the compressed air manual valve b are installed in sequence on the branch.

[0010] A compressed air bypass pipeline (P5) is connected in parallel with the compressed air branch line (P4). A compressed air bypass manual valve is installed on the compressed air branch line (P4) to provide a path for directly conveying compressed air.

[0011] Furthermore, the integrated compressed air and nitrogen control system also includes:

[0012] The nitrogen branch pressure measuring point is set on the nitrogen branch (P1) and is used to monitor the pressure of the nitrogen branch (P1).

[0013] The compressed air branch pressure measuring point is set on the compressed air branch (P4) and is used to monitor the pressure of the compressed air branch.

[0014] The user-end pipeline (P6) is used to connect the nitrogen branch (P1) or the compressed air branch (P4) to transport the gas to the user end.

[0015] The user pressure measuring point is set on the user-side pipeline (P6) to monitor the pressure at the user-side.

[0016] The user flow measurement point is set on the user-side pipeline (P6) to monitor the gas flow to the user.

[0017] The nitrogen system pressure measuring point is set in the nitrogen system to monitor the pressure condition of the entire nitrogen system.

[0018] The compressed air system pressure measuring point is set in the compressed air system to monitor the pressure condition of the entire compressed air system.

[0019] Remote control system that integrates all data and manages the automation of the entire system.

[0020] On-site indicator lights are used to display the current status for reference by on-site staff.

[0021] Furthermore, a first parallel branch is arranged outside the nitrogen electric valve a, and a nitrogen charging valve is arranged in the first parallel branch; a second parallel branch is arranged outside the compressed air electric valve a, and a compressed air charging valve is arranged in the second parallel branch.

[0022] The integrated control method of compressed air and nitrogen includes: the control method is based on the control system, and the control method includes three working conditions:

[0023] Working condition 1: Compressed air is switched to nitrogen.

[0024] Working condition 2: Nitrogen is switched to compressed air.

[0025] Working condition three: switch to emergency gas source.

[0026] Further, in working condition 1, the steps are included:

[0027] S1. Compressed air is used as the first air source for dust removal or desulfurization process.

[0028] S2. When the remote control system detects that the pressure Py of the compressed air system shows a decreasing trend rate v, the estimated time t = (Py-Px) / v for the pressure to drop to the safety pressure Px is calculated.

[0029] S3. Considering the device switching action time t1, determine the actual monitored safety pressure Ps=t1*v+Px.

[0030] S4. According to the action time of nitrogen electric valve a, nitrogen electric valve b, nitrogen pressure relief valve and nitrogen pressure equalizing valve, and the volume V of the pipe section between nitrogen electric valve a and nitrogen electric valve b, calculate the pressure equalizing time tc=V / Vn, where Vn is the charging flow identified according to the nitrogen system pressure Pn.

[0031] S5. Calculate the switching time t1=tnb+tna+tnx+tc, and update the monitored safety pressure Ps accordingly; wherein tnb represents the action time of the nitrogen electric valve b, tna represents the action time of the nitrogen electric valve a, and tnx represents the action time of the nitrogen pressure relief valve.

[0032] S6. The control system monitors the nitrogen system pressure Pn and the compressed air pressure drop rate v in real time with a 1 second scanning cycle.

[0033] S7. When the real-time pressure P of the compressed air system is less than the monitoring safety pressure Ps plus the redundant pressure Pr, the control result is output to switch the compressed air to nitrogen.

[0034] S8. The remote control system sends a signal to the on-site indicator of the gas consumption point, indicating that the current gas source has been switched to nitrogen.

[0035] Furthermore, when the device is put into use, the nitrogen manual valve a, nitrogen manual valve b, compressed air manual valve a, and compressed air manual valve b are in the open state and are only used for maintenance of the nitrogen branch and compressed air branch; while the nitrogen bypass manual valve, compressed air bypass manual valve and nitrogen emergency electric valve are closed when the device is put into use and are only used for emergency purposes.

[0036] The pressure fluctuation range of the compressed air system is 0.55Mpa-0.78Mpa, and the pressure fluctuation range at the user end is 0.45Mpa-0.68Mpa.

[0037] When it is detected that the system pressure is showing a downward trend and the pressure drop per unit time exceeds 0.01Mpa, the drop rate is defined as 0.01Mpa / 5s.

[0038] The minimum safety pressure limit Px is a constant designed according to the needs of each process. For the desulfurization process, the limit shall not be lower than 0.5Mpa.

[0039] Furthermore, in working condition 2, the steps are included:

[0040] S1. The remote control system compares the real-time pressure P of the compressed air system with the monitored safety pressure Ps plus the redundant pressure Pr.

[0041] S2. When the remote control system identifies that P>Ps+Pr and detects that the pressure trend of the compressed air system is rising, it outputs a control command to close the compressed air pressure relief valve and continues to the next step after confirming that the valve is in place.

[0042] S3. Open the compressed air charging valve to inflate the pipe section between the compressed air electric valve a and the compressed air electric valve b.

[0043] S4. Monitor and identify through the remote control system whether the value of the compressed air branch pressure measuring point is consistent with the value of the compressed air system pressure measuring point.

[0044] S5. When the pressure values ​​of the above two measuring points match, close the compressed air charging valve, and then open the compressed air electric valve a and the compressed air electric valve b.

[0045] S6. Further monitor whether the pressure value of the user's pressure measuring point is consistent with the value of the compressed air system pressure measuring point through the remote control system.

[0046] S7. When the pressure value at the user's pressure measuring point matches the pressure value at the compressed air system's pressure measuring point, the remote control system prompts that the compressed air branch has been opened.

[0047] S8. Close the nitrogen electric valve a and the nitrogen electric valve b. After confirming that both electric valves are in place, open the nitrogen pressure relief valve to relieve the pressure of the nitrogen branch.

[0048] S9. The value of the nitrogen branch pressure measuring point is monitored through the remote control system until it is recognized that the value is zero, at which time it is prompted that the nitrogen branch has been closed.

[0049] S10. The remote control system sends a signal to the on-site indicator, indicating that the nitrogen has been successfully switched to compressed air.

[0050] Furthermore, before closing the compressed air pressure relief valve, the remote control system first confirms that the pressure trend of the compressed air system is rising.

[0051] Before the compressed air charging valve is opened, it is first confirmed that the compressed air pressure relief valve has been completely closed.

[0052] Before the compressed air electric valve a and the compressed air electric valve b are opened, it is necessary to ensure that the pressure value of the compressed air branch pressure measuring point is consistent with the pressure measuring point of the compressed air system.

[0053] Before closing, the nitrogen electric valve a and the nitrogen electric valve b need to wait for the pressure value of the user's pressure measuring point to be consistent with the pressure value of the compressed air system's pressure measuring point.

[0054] Before opening the nitrogen pressure relief valve, it is necessary to confirm that both nitrogen electric valve a and nitrogen electric valve b are completely closed.

[0055] Before sending a signal indicating that nitrogen has been successfully switched to compressed air, the remote control system needs to confirm that the pressure value at the nitrogen branch pressure measuring point is zero.

[0056] The redundant pressure Pr is an artificially set safety margin used to ensure the energy safety of the process.

[0057] Furthermore, in working condition 3, the steps are included:

[0058] S1. The remote control system monitors the value of the user's pressure measuring point and identifies that the value is less than the user's minimum safety pressure limit Px, where Px is a constant of the process's own attributes.

[0059] S2. The remote control system simultaneously monitors the value of the user flow measurement point and recognizes that the value is on a downward trend.

[0060] S3. When the above conditions are met, the remote control system outputs control instructions to keep all the electric valves of the nitrogen branch and the compressed air branch at their current positions.

[0061] S4. Open the nitrogen emergency electric valve at the same time, and the remote control system issues a fault warning.

[0062] S5. If the remote control system continues to identify that the value of the user pressure measurement point is less than the user's minimum safety pressure limit Px and the value of the user flow measurement point is still on a downward trend, the fault warning is upgraded.

[0063] S6. After the fault warning is upgraded, the remote control system identifies the values ​​of the nitrogen system pressure measuring points and the compressed air system pressure measuring points.

[0064] S7. According to the values ​​of the nitrogen system pressure measuring point and the compressed air system pressure measuring point, select the branch that is greater than Px, and give the operation prompts for opening the nitrogen bypass manual valve or the compressed air bypass manual valve, where the priority is: if the values ​​of the nitrogen system pressure measuring point and the compressed air system pressure measuring point are both greater than Px, it is preferred to open the nitrogen bypass manual valve.

[0065] Furthermore, when the value of the user pressure measuring point is less than the user's minimum safety pressure limit Px, the remote control system immediately takes measures to prevent further pressure drop.

[0066] After the fault warning is upgraded, the remote control system will provide clear operating instructions to guide the operator to open the corresponding bypass manual valve to restore the gas supply.

[0067] If only one of the values ​​of the nitrogen system pressure measuring point and the compressed air system pressure measuring point is greater than Px, the remote control system will instruct to open the bypass manual valve of the corresponding branch with higher pressure.

[0068] The user's minimum safety pressure limit Px is a constant designed according to the needs of each process to ensure the safe operation of the process.

[0069] Compared with the prior art, the present invention has beneficial effects.

[0070] The system of the present invention realizes the control switching between nitrogen and compressed air. The system can automatically issue instructions and coordinate the operation of multiple valve groups to achieve integrated switching of the two gas sources. In addition, the system also has remote feedback and early warning functions to ensure that the risk of nitrogen and compressed air mixing with each other is eliminated during the switching process.

[0071] 1. The present invention realizes automatic switching between two gas sources: nitrogen and compressed air.

[0072] 2. Pressure measuring points and pressure relief valves are set in the pipe sections between the electric valves, which can perform status self-checks after switching and feed back the results to the control system.

[0073] 3. The existence of the pressure relief valve prevents the two media - nitrogen and compressed air from mixing with each other.

[0074] 4. The system makes predictions based on the pressure trend of the compressed air system, thereby completing timely switching of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. The protection scope of the present invention is not limited to the following description.

[0076] Figure 1 It is a principle block diagram of a compressed air and nitrogen integrated control system.

[0077] Figure 2 It is a schematic diagram of the comparative table of embodiments.

[0078] In the figure, 1. nitrogen manual valve a, 2. nitrogen check valve, 3. nitrogen charging valve, 4. nitrogen electric valve a, 5. nitrogen pressure relief valve, 6. nitrogen electric valve b, 7. nitrogen manual valve b, 8. nitrogen bypass manual valve, 9. compressed air manual valve a, 10. compressed air check valve, 11. compressed air charging valve, 12. compressed air electric valve a, 13. compressed air pressure relief valve, 14. compressed air electric valve b, 15. compressed air manual valve b, 16. compressed air bypass manual valve, 17. nitrogen emergency electric valve, 18. nitrogen emergency check valve, 19. nitrogen branch pressure measuring point, 20. compressed air branch pressure measuring point, 21. compressed air system pressure measuring point, 22. nitrogen system pressure measuring point, 23. user pressure measuring point, 24. user flow measuring point, 25. remote control system, 26 on-site indication. DETAILED DESCRIPTION

[0079] In order to make the purpose, technical scheme and beneficial effects of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0080] like Figure 1-2 As shown, in the integrated control system of compressed air and nitrogen, according to the process requirements, either nitrogen or compressed air source (usually compressed air) is used as the main gas source for the user, and the other gas source is used as a backup.

[0081] Working principle description: Taking compressed air as the first air source as an example, when the user uses compressed air, the remote control system monitors the compressed air system pressure in real time and calculates the compressed air pressure increase or decrease rate.

[0082] When it is detected that the pressure reduction rate and the real-time pressure meet the switching conditions, the nitrogen switching valve group starts to open: close the pressure relief valve, and after detecting that the valve is in place, open the charging valve. After detecting that the pressure measuring point of the nitrogen branch is consistent with the pressure measuring point of the nitrogen system, open the two electric valves of the nitrogen branch, and close the charging valve synchronously, and the nitrogen branch is opened.

[0083] At the same time, the pressure at the user pressure measuring point matches the pressure at the nitrogen branch pressure measuring point and the nitrogen system pressure, and the nitrogen branch opening is fed back to indicate that it has ended.

[0084] The compressed air valve group begins to close, and the two electric valves of the compressed air branch are closed synchronously. After detecting that the two electric valves are fully closed, the pressure relief valve is opened, and the pressure measuring point of the compressed air branch is monitored to be zero, and the closure of the compressed air branch is completed.

[0085] At the same time, the remote monitoring system prompts that the gas source has been switched to nitrogen. The remote switching, remote confirmation and elimination of cross-gas between nitrogen and compressed air are achieved. Each branch contains manual valves at both ends of the branch. When the branch is put into use normally, both valves are in the open state. If the components of the branch fail, the two manual valves can be closed to carry out maintenance on the branch without affecting the normal functions of the remaining branches and the normal energy consumption of the users; the check valve on the main pipeline of each branch further ensures the isolation effect of the manual valve on the process side when the branch is out of use; two electric valves are installed on the main pipeline of each branch for remote control of the commissioning and shutdown of the branch; a pressure relief valve branch is added to the main pipeline between the two electric valves of each branch to discharge the residual gas between the two electric valves when the branch stops running.

[0086] At the same time, a pressure measuring point is added to the main pipeline between the two electric valves to detect the pressure between the two electric valves and serve as a basis for judging whether the branch is effectively isolated. Taking advantage of the stability of the nitrogen system, a nitrogen gas source is introduced as an emergency gas source. If the system switching fails and the user pressure is lower than the safety limit, the emergency gas source is immediately turned on and the remote control system alarms. At the same time, the original switching valve is retained for manual opening in the event of abnormal situations such as sudden system power failure to ensure user energy use.

[0087] Specifically, the compressed air and nitrogen integrated control system includes a nitrogen branch consisting of a nitrogen manual valve a1, a nitrogen check valve 2, a nitrogen charging valve 3, a nitrogen electric valve a4, a nitrogen pressure relief valve 5, a nitrogen electric valve b6, a nitrogen manual valve b7, a nitrogen bypass manual valve 8, and a nitrogen branch pressure measuring point 19.

[0088] The compressed air branch consists of a compressed air manual valve a9, a compressed air check valve 10, a compressed air charging valve 11, a compressed air electric valve a12, a compressed air pressure relief valve 13, a compressed air electric valve b14, a compressed air manual valve b15, a compressed air bypass manual valve 16, and a compressed air branch pressure measuring point 20.

[0089] An emergency branch consisting of a nitrogen emergency electric valve 17 and a nitrogen emergency check valve 18.

[0090] The system is composed of auxiliary units including a compressed air system pressure measuring point 21, a nitrogen system pressure measuring point 22, a user pressure measuring point 23, a user flow measuring point 24, a remote control system 25, and a field indication 26.

[0091] Example 1: Compressed air is switched to nitrogen:

[0092] In the dust removal or desulfurization process, compressed air is used as the first gas source. Due to the large pressure fluctuations in the compressed air system, generally, the gas source pressure fluctuates in the range of 0.55Mpa-0.78Mpa, and the user pressure fluctuates in the range of 0.45-0.68Mpa (most users use it in an impact manner). The remote control system 25 monitors the pressure Py fluctuations of the compressed air system 21, and the pressure drop trend rate v (the system pressure is detected to be decreasing. Within a unit time, for example, 5 seconds, the pressure drops by more than 0.01Mpa, then the pressure drop rate is 0.01Mpa / 5s), combined with the user's minimum safety pressure limit Px, the minimum safety pressure limit Px is the process's own attribute and is a constant. (For example, in the desulfurization process, the power gas use pressure must not be lower than 0.5Mpa. This value is the minimum pressure designed for each process according to its own needs, that is, the safety pressure) The estimated time to drop to the safety pressure is t = (Py-Px) / v. Since there is an action time t1 (device's own property, constant) when the device switches, the actual monitored safety pressure Ps=t1*v+Px can be calculated.

[0093] Device switching action time t1: nitrogen electric valve b 6 action time tnb, nitrogen electric valve a 4 action time tna, nitrogen pressure relief valve 5 action time tnx, nitrogen pressure equalizing valve 3 action time tnj. Among them, tnb, tna, tnj, tnx are all valve properties, which are constants.

[0094] Pressure equalization time tc: punching pipeline diameter d, nitrogen real-time monitoring pressure Pn, a flow comparison table can be established based on the pipe diameter and pressure, and the flow comparison table is implanted into the remote control system 25, and the charging flow Vn is identified according to the pressure of the nitrogen system 22, and the pipe section volume V between the nitrogen electric valve a 4 and the nitrogen electric valve b 6 (device own property, constant), then the pressure equalization time tc = V / Vn, the switching time t1 = tnb + tna + tnx + tc.

[0095] Monitor the compressed air safety pressure: Ps = (tnb + tna + tnx + V / Vn) * v + Px. Because the nitrogen pressure Pn and the compressed air pressure drop rate v change in real time, the control system needs to identify the nitrogen system 22 pressure and the compressed air pressure drop rate in real time (scanning cycle 1s), and output the result. According to the comparison between the real-time pressure of the compressed air system 21 and the monitored safety pressure, P < Ps + Pr (redundant pressure, to ensure the safety of process energy use, manually set, can be combined with emergency time) output control results: compressed air is switched to nitrogen. At the same time, the remote control system user 25 sends a signal to the on-site indication 26 of the gas consumption point, prompting the current gas source nitrogen.

[0096] When put into use, nitrogen manual valve a1, nitrogen manual valve b7, compressed air manual valve a9, and compressed air manual valve b15 are in the open state and are only used for maintenance of nitrogen branch and compressed air branch, and do not participate in switching adjustment; nitrogen bypass manual valve 8, compressed air bypass manual valve 16, and nitrogen emergency electric valve 17 are in the closed state when the device is put into use and are only used for emergency.

[0097] The specific switching actions are as follows:

[0098] The remote control system 25 compares the real-time pressure of the compressed air system 21 with the monitored safety pressure and identifies that P < P s +P r .

[0099] Remote control system 25 output controls valve action:

[0100] After closing the nitrogen pressure relief valve 5 and checking that the valve is in place, open the nitrogen charging valve 3, and inflate the pipe section between the nitrogen electric valve a4 and the nitrogen electric valve b6. After the remote control system 25 recognizes that the value of the nitrogen branch pressure measuring point 19 matches the value of the nitrogen system pressure measuring point 22, close the nitrogen charging valve 3, open the nitrogen electric valve a4 and the nitrogen electric valve b6, and after the remote control system 25 recognizes that the pressure value of the user pressure measuring point 24 matches the value of the nitrogen system pressure measuring point 22 (theoretically, the values ​​are equal, but considering the distance and sequence of the two measuring points, it is necessary to fully consider the pressure drop caused by pipeline resistance and the instrument measurement error, and give a range. For example, P 22 =P 24 ±0.005Mpa, that is, the default value is consistent), indicating that the nitrogen branch is open. Close the compressed air electric valve a 12 and the compressed air electric valve b 14. After the two electric valves are in place, open the compressed air pressure relief valve 13 to release the pressure. After the remote control system 25 recognizes that the value of the pressure measurement point of the compressed air branch 20 is zero, it indicates that the compressed air branch 20 is closed. At the same time, the remote control system 25 sends a signal to the on-site indication 26: the compressed air has been switched to nitrogen.

[0101] Example 2: Nitrogen is switched to compressed air.

[0102] The remote control system 25 compares the real-time pressure of the compressed air system 21 with the monitored safety pressure and identifies that P>P s +P r , and it is recognized that the pressure trend of the pressure measuring point 21 of the compressed air system is displayed as pressure rising, the remote control system 25 outputs the control valve action: after closing the compressed air pressure relief valve 13 and detecting that the valve is in place, the compressed air charging valve 11 is opened to inflate the pipe section between the compressed air electric valve a 12 and the compressed air electric valve b 14. After the remote control system 25 recognizes that the value of the compressed air branch pressure measuring point 20 is consistent with the value of the compressed air system pressure measuring point 21, the compressed air charging valve 11 is closed, and the compressed air electric valve a 12 and the compressed air electric valve b 14 are opened. After the remote control system 25 recognizes that the pressure value of the user pressure measuring point 24 is consistent with the value of the compressed air system pressure measuring point 21, it indicates that the compressed air branch is opened; close the nitrogen electric valve a 4 and the nitrogen electric valve b 6. After the two electric valves are in place, open the nitrogen pressure relief valve 5 for pressure relief. After the remote control system 25 recognizes that the value of the nitrogen branch pressure measuring point 19 is zero, it indicates that the compressed air branch is closed. At the same time, the remote control system 25 sends a signal to the on-site indication 26: the nitrogen gas has been switched to nitrogen gas.

[0103] Embodiment 3: Switch to emergency gas source.

[0104] The remote control system 25 recognizes that the value of the user pressure measurement point 24 is less than the user's minimum safety pressure limit Px (process attribute, constant), and the value of the user flow measurement point 23 is on a downward trend. The remote control system 25 outputs the control valve action:

[0105] All electric valves of the nitrogen branch and the compressed air branch are put into position and maintained, while the nitrogen emergency electric valve 17 is opened, and the remote control system 25 issues a fault warning.

[0106] If the remote control system 25 can still identify that the value of the user pressure measurement point 24 is less than the user's minimum safety pressure limit Px, and the value of the user flow measurement point 23 is on a downward trend, the remote control system 25 will upgrade the warning, identify the values ​​of the nitrogen system pressure measurement point 22 and the compressed air system pressure measurement point 21, select the branch with a value greater than Px, and give an operation prompt to open the nitrogen bypass manual valve 8 or the compressed air bypass manual valve 16. Priority: If the values ​​of the nitrogen system pressure measurement point 22 and the compressed air system pressure measurement point 21 are both greater than Px, the nitrogen bypass manual valve 8 is selected.

[0107] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. Therefore, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A compressed air and nitrogen integrated control system, characterized in that: include: A nitrogen branch (P1), which is used to connect the nitrogen source and the user, and is equipped with a nitrogen manual valve a (1), a nitrogen check valve (2), a nitrogen electric valve a (4), a nitrogen pressure relief valve (5), a nitrogen electric valve b (6) and a nitrogen manual valve b (7) in sequence; A nitrogen bypass pipeline (P2), which is connected in parallel with the nitrogen branch line (P1), and a nitrogen bypass manual valve (8) is installed on the nitrogen bypass pipeline (P2) to provide a path for directly conveying gas; A nitrogen emergency shut-off pipeline (P3) is connected in parallel with the nitrogen branch (P1), and a nitrogen emergency electric valve (17) and a nitrogen emergency check valve (18) are installed in series on the nitrogen emergency shut-off pipeline (P3) for rapid shut-off in an emergency; and the nitrogen emergency electric valve (17) is controlled by a remote control system; A compressed air branch (P4), which is used for connecting the compressed air source and the user, and is provided with a compressed air manual valve a (9), a compressed air check valve (10), a compressed air electric valve a (12), a compressed air pressure relief valve (13), a compressed air electric valve b (14), and a compressed air manual valve b (15) in sequence; A compressed air bypass pipeline (P5) is connected in parallel with the compressed air branch line (P4). A compressed air bypass manual valve (16) is installed on the compressed air branch line (P4) to provide a path for directly conveying compressed air.

2. The integrated compressed air and nitrogen control system according to claim 1, characterized in that: Also includes: A nitrogen branch pressure measuring point (19), arranged on the nitrogen branch (P1), for monitoring the pressure of the nitrogen branch (P1); A compressed air branch pressure measuring point (20), arranged on the compressed air branch (P4), for monitoring the pressure of the compressed air branch; The user-end pipeline (P6) is used to connect the nitrogen branch (P1) or the compressed air branch (P4) to transport the gas to the user end; A user pressure measuring point (23), which is arranged on the user-side pipeline (P6) and is used to monitor the pressure at the user-side; A user flow measurement point (24), which is arranged on the user-side pipeline (P6) and is used to monitor the gas flow to the user; A nitrogen system pressure measuring point (22), arranged in the nitrogen system, for monitoring the pressure condition of the entire nitrogen system; A compressed air system pressure measuring point (21), arranged in the compressed air system, for monitoring the pressure condition of the entire compressed air system; A remote control system (25) for integrating all data and managing the automated operation of the entire system; The on-site indicator light (26) is used to display the current status for reference by on-site staff.

3. The integrated compressed air and nitrogen control system according to claim 1, characterized in that: A first parallel branch is arranged outside the nitrogen electric valve a (4), and a nitrogen charging valve (3) is arranged in the first parallel branch; a second parallel branch is arranged outside the compressed air electric valve a (12), and a compressed air charging valve (11) is arranged in the second parallel branch.

4. The integrated control method of compressed air and nitrogen is characterized in that: include: The control method is based on a control system, and the control system is the control system described in any one of claims 1 to 3; the control method includes three working conditions: Working condition 1: Compressed air is switched to nitrogen; Working condition 2: nitrogen is switched to compressed air; Working condition three: switch to emergency gas source.

5. The method for integrated control of compressed air and nitrogen according to claim 4, characterized in that: Working condition 1 includes the following steps: S1, compressed air is used as the first air source for dust removal or desulfurization process; S2. When the remote control system (25) detects that the pressure Py of the compressed air system (21) shows a decreasing trend rate v, the estimated time t to drop to the safe pressure Px is calculated = (Py-Px) / v; S3, considering the device switching action time t1, determine the actual monitoring safety pressure Ps = t1*v + Px; S4, according to the action time of the nitrogen electric valve a (4), the nitrogen electric valve b (6), the nitrogen pressure relief valve and the nitrogen pressure equalizing valve, and the volume V of the pipe section between the nitrogen electric valve a (4) and the nitrogen electric valve b (6), calculate the pressure equalizing time tc = V / Vn, where Vn is the charging flow rate identified according to the nitrogen system pressure Pn; S5, calculate the switching time t1 = tnb + tna + tnx + tc, and update the monitoring safety pressure Ps accordingly; wherein tnb represents the action time of the nitrogen electric valve b (6), tna represents the action time of the nitrogen electric valve a (4), and tnx represents the action time of the nitrogen pressure relief valve (5); S6, the control system monitors the nitrogen system pressure Pn and the compressed air pressure drop rate v in real time with a 1 second scanning cycle; S7. When the real-time pressure P of the compressed air system is less than the monitoring safety pressure Ps plus the redundant pressure Pr, the control result is output to switch the compressed air to nitrogen; S8. The remote control system sends a signal to the on-site indicator of the gas consumption point, indicating that the current gas source has been switched to nitrogen.

6. The method according to claim 5, characterized in that: When the device is put into use, the nitrogen manual valve a, nitrogen manual valve b, compressed air manual valve a, and compressed air manual valve b are in the open state and are only used for nitrogen branch and compressed air branch maintenance; while the nitrogen bypass manual valve, compressed air bypass manual valve and nitrogen emergency electric valve are closed when the device is put into use and are only used for emergency; The pressure fluctuation range of the compressed air system is 0.55Mpa-0.78Mpa, and the pressure fluctuation range of the user end is 0.45Mpa-0.68Mpa; When it is detected that the system pressure is showing a downward trend and the pressure drop per unit time exceeds 0.01Mpa, the drop rate is defined as 0.01Mpa / 5s. The minimum safety pressure limit Px is a constant designed according to the needs of each process. For the desulfurization process, the limit shall not be lower than 0.5Mpa.

7. The method according to claim 4, characterized in that: Working condition 2 includes the following steps: S1, the remote control system (25) compares the real-time pressure P of the compressed air system (21) with the monitored safety pressure Ps plus the redundant pressure Pr; S2. When the remote control system (25) identifies that P>Ps+Pr and detects that the pressure trend of the compressed air system (21) is rising, it outputs a control instruction to close the compressed air pressure relief valve (13), and continues the next step after confirming that the valve is in place; S3, opening the compressed air charging valve (11) to inflate the pipe section between the compressed air electric valve a (12) and the compressed air electric valve b (14); S4, monitoring and identifying, through the remote control system (25), whether the value of the compressed air branch pressure measuring point (20) is consistent with the value of the compressed air system pressure measuring point (21); S5. When the pressure values ​​of the two measuring points match, close the compressed air charging valve (11), and then open the compressed air electric valve a (12) and the compressed air electric valve b (14); S6. Further monitoring, through the remote control system (25), whether the pressure value of the user pressure measuring point (24) is consistent with the value of the compressed air system pressure measuring point (21); S7. When the pressure value at the user pressure measuring point (24) matches the pressure value at the compressed air system pressure measuring point (21), the remote control system (25) prompts that the compressed air branch has been opened; S8, close the nitrogen electric valve a (4) and the nitrogen electric valve b (6), and after confirming that both electric valves are in place, open the nitrogen pressure relief valve (5) to relieve the pressure of the nitrogen branch; S9, monitoring the value of the nitrogen branch pressure measuring point (19) through the remote control system (25) until the value is identified as zero, and then prompting that the nitrogen branch has been closed; S10. The remote control system (25) sends a signal to the on-site indicator (26), indicating that the nitrogen has been successfully switched to compressed air.

8. The method according to claim 7, characterized in that: The remote control system (25) first confirms that the pressure trend of the compressed air system (21) is rising before closing the compressed air pressure relief valve (13); Before the compressed air charging valve (11) is opened, it is first confirmed that the compressed air pressure relief valve (13) has been completely closed; Before the compressed air electric valve a (12) and the compressed air electric valve b (14) are opened, it is necessary to ensure that the pressure values ​​of the compressed air branch pressure measuring point (20) and the compressed air system pressure measuring point (21) are consistent; Before closing, the nitrogen electric valve a (4) and the nitrogen electric valve b (6) need to wait for the pressure value of the user pressure measuring point (24) to be consistent with the pressure value of the compressed air system pressure measuring point (21); Before the nitrogen pressure relief valve (5) is opened, it is necessary to confirm that the nitrogen electric valve a (4) and the nitrogen electric valve b (6) are completely closed; Before sending a signal indicating that nitrogen has been successfully switched to compressed air, the remote control system (25) needs to confirm that the pressure value of the nitrogen branch pressure measuring point (19) is zero; The redundant pressure Pr is an artificially set safety margin used to ensure the energy safety of the process.

9. The method according to claim 4, characterized in that: Working condition 3 includes the following steps: S1, the remote control system (25) monitors the value of the user pressure measuring point (24), and recognizes that the value is less than the user's minimum safety pressure limit Px, where Px is a constant of the process's own attributes; S2, the remote control system (25) simultaneously monitors the value of the user flow measurement point (23) and recognizes that the value is on a downward trend; S3. When the above conditions are met, the remote control system (25) outputs a control instruction to keep all the electric valves of the nitrogen branch and the compressed air branch in their current positions unchanged; S4. At the same time, the nitrogen emergency electric valve (17) is opened, and a fault warning is issued by the remote control system (25); S5. If the remote control system (25) continues to identify that the value of the user pressure measurement point (24) is less than the user's minimum safety pressure limit Px and the value of the user flow measurement point (23) is still on a downward trend, the fault warning is upgraded; S6. After the fault warning is upgraded, the remote control system (25) identifies the values ​​of the nitrogen system pressure measuring point (22) and the compressed air system pressure measuring point (21); S7. According to the values ​​of the nitrogen system pressure measuring point (22) and the compressed air system pressure measuring point (21), a branch greater than Px is selected, and an operation prompt for opening the nitrogen bypass manual valve (8) or the compressed air bypass manual valve (16) is given, wherein the priority is: if the values ​​of the nitrogen system pressure measuring point (22) and the compressed air system pressure measuring point (21) are both greater than Px, opening the nitrogen bypass manual valve (8) is preferred.

10. The method according to claim 9, characterized in that: When the value of the user pressure measuring point (24) is less than the user's minimum safety pressure limit Px, the remote control system (25) immediately takes measures to prevent further pressure drop; After the fault warning is upgraded, the remote control system (25) will provide clear operating instructions to guide the operator to open the corresponding bypass manual valve to restore the gas supply; If only one of the values ​​of the nitrogen system pressure measuring point (22) and the compressed air system pressure measuring point (21) is greater than Px, the remote control system (25) will instruct to open the bypass manual valve of the corresponding branch with higher pressure; The user's minimum safety pressure limit Px is a constant designed according to the needs of each process to ensure the safe operation of the process.

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