Could those who are involved in the operation and control of ammonia synthesis share specific methods for designing and implementing control systems, based on their own work experience?
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It would be best to have a flowchart related to it with control points. The operation interface of the DCS system, control requirements, configuration schemes, etc. It’s just daily work. It would be better if there were preliminary designs and detailed designs. How is the nitrogen-to-hydrogen ratio adjusted? Comparison and implementation of control schemes. What are those control points? Are there chains or anything like that? It is more suitable for self-control design.
There’s too much of it; I don’t know how to start talking about it. . . However, in terms of the hydrogen-to-nitrogen ratio, we use moldless control. This post was last edited by *aoye613 on 2009-3-24 11:09]
I have seen many flowcharts for the synthetic ammonia production process used in teaching, which include control points, but there is no textual explanation. The safety technical regulations for equipment in enterprises are detailed into categories such as pressure, temperature, flow rate, and liquid level. There is a table. List all the control points, instrument types, and measurement methods, etc. Important steps have separate flowcharts with control points. Just like textbooks, it’s clear at a glance what they are about. Some friends have indeed uploaded introductions. In the technical specifications, however, the flowcharts were “neglected”. It’s only possible to take a look.
Deoxidation tank level safety interlock 1) Purpose of the interlock: This interlock is installed to ensure that the liquid level in the deoxidation tank remains within normal limits. When the level of the deoxygenation tank is too low, the feed water pump 2004J or 2004JA is automatically started. 2) Parameter table: Bit number, interlock value (%), normal state, accident state. LI23B: 15; VS-6: energized, de-energized; JM: open, closed. 3) Logic diagram. 4) Interlock description: a. Interlock input: LI23B, which indicates the level of the deoxygenation tank. b. Interlock output: VS6 – the solenoid valve controlled by V-6; JM – the contact that activates 2004JA. c. Interlock operation description: One of the following factors will trigger the solenoid valve VS6: when PB2004JT is in the “operational” state, and LI23B reaches the interlock value ； l Press the soft button PB2004JT ； The following factors will trigger contact JM: l LI23B reaches the interlock value ； Interlock for emergency air damper in Section 1 furnace auxiliary boiler 1) Purpose of the interlock: To ensure that Section 1 furnace burns under negative pressure; when the air pressure at the blower outlet is too low, the emergency air damper opens automatically. 2) Parameter Table: Bit Number, Low-Low Interlock Value, Normal State, Accident State
PI300A: 392 Pa
PI300B: 392 Pa
SI6: 500 RPM
VS300A/B: Powered, De-energized
VS301A/B: Powered, De-energized
VS302A/B: Powered, De-energized
VS304A/B: Powered, De-energized
3) Logic Diagram
4) Interlock Instructions
a. Interlock Inputs:
PI300A: Fan outlet pressure detection (original tag number: PI300)
PI300B: Fan outlet pressure detection (newly added)
SI6: Fan speed detection
HS303: Interlock activation/deactivation switch; when the switch is set to “Activated”, the interlock is active (switch in “ON” position), and when it is set to “Deactivated”, the interlock is disabled (switch in “OFF” position).
b. Interlock Outputs:
VS300A/B: 101-BU accident air damper solenoid valve
VS301A/B: 101-B accident air damper solenoid valve
VS302A/B: 101-B accident air damper solenoid valve
VS304A/B: Overheating burner ignition solenoid valve
c. Interlock Operation Instructions:
HS300: Control button for the 101-BU accident air damper; “CLOSE” indicates closing the 101-BU accident air damper, while “OPEN” indicates opening it. HS301: Control button for the accident air damper of 101-B. “CLOSE” indicates closing the accident air damper of 101-B, while “OPEN” indicates opening it. HS302: Control button for the accident air damper of 101-B. “CLOSE” indicates closing the accident air damper of 101-B, while “OPEN” indicates opening it. HS303: Overall interlock shutdown and activation. One of the following factors will trigger solenoid valves VS300A/B to lose power, causing the accident air damper 101-BU to open: When the HS303 interlock activation/shutdown switch is set to the “active” position, PI300A, PI300B, and SI6 all reach their interlock values ； When the HS303 interlock activation/deactivation switch is set to the “activated” position, it is still possible to press HS300 even if PI300A, PI300B, and SI6 do not meet the interlock conditions ； l When the HS303 interlock activation/deactivation switch is set to the \"deactivated\" position, HS300 can also be forced to be activated ； One of the following factors will trigger solenoid valves VS301A/B to lose power, causing the accident air damper 101-B to open: When the HS303 interlock activation/deactivation switch is set to the “active” position, PI300A, PI300B, and SI6 all reach their interlock values ； When the HS303 interlock activation/deactivation switch is set to the \"active\" position, it is still possible to press HS301 even if PI300A, PI300B, and SI6 do not meet the interlock conditions ； l When the HS303 interlock enable/disable switch is set to the “disabled” position, HS301 can also be forced to be pressed ； One of the following factors will trigger solenoid valves VS302A/B to lose power, causing the accident air damper 101-B to open: when the HS303 interlock activation/deactivation switch is set to the “activated” position, PI300A, PI300B, and SI6 all reach their interlock values ； When the HS303 interlock activation/deactivation switch is set to the \"activated\" position, HS302 can also be pressed even if PI300A, PI300B, and SI6 do not meet the interlock conditions ； l When the HS303 interlock enable/disable switch is set to the \"Disable\" position, HS302 can also be forced to be pressed ； Interlock for Process Condensate Stripping Tower 150-E 1) Purpose of the interlock: To ensure the recovery of qualified process condensate; when the conductivity of the process condensate at the outlet of 150E is high, the interlock activates to discharge the condensate. 2) Parameter table: Bit number, interlock value, normal state, accident state. AI10: 200μs/cm; XY10A: energized, de-energized; XY10B: de-energized, energized. 3) Logic diagram. 4) Interlock description: a. Interlock input: AI10 – conductivity of the process condensate at the bottom of Tower 150-E. b. Interlock outputs: XY10A to the solenoid valve connected to AV10A; XY10B to the solenoid valve connected to AV10B. c. Interlock operation description: One of the following factors will trigger the solenoid valves XY10A and XY10B – when XY10A is de-energized, AV10A opens and the condensate is discharged; when XY10B is energized, AV10B closes. This occurs when PBAV10 is in the “operational” state and AI10 reaches the interlock value ； l Press the soft button PBAV10 ； Interlock for fuel gas at the top burner of Section 1 furnace: 1) Purpose of the interlock – To ensure safe ignition of the top burner in Section 1 furnace, and to guarantee that no fuel gas leaks into the furnace chamber before ignition. During normal operation, it prevents flameout caused by excessive fuel gas pressure, as well as shutdown caused by insufficient fuel gas pressure. 2) Parameter table: Bit number – Low/low interlock value (kPa), High/high interlock value (kPa); Normal state, Accident state. PI121A: 20, 330; PI121B: 20, 330; PI95: 20; VS30: De-energized/ Energized. 3) Logic diagram. 4) Interlock instructions: a. Interlock inputs: PI121A – Fuel pressure indicator after V30 valve; PI121B – Fuel pressure indicator after V30 valve; PI95 – Pressure indicator of the check gas; SW_121 – Switch for enabling/disabling the interlocks of PI121A and B; it is OFF when the interlocks are disabled, and ON when they are enabled. SW_95 – Switch for enabling/disabling the interlock of PI95; it is OFF when the interlock is disabled, and ON when it is enabled. b. Interlock outputs: VS30 – Solenoid valve connected to V30; another output is connected to the interlock PB306, which shuts off the fuel gas supply to the top burner of 101B. c. Interlock operation instructions: When the bypass switch “BYPASS” for PB30 is OFF, the following conditions will cause VS30 to become energized and the V30 valve to close: When both the indicators PI121A and PI121B exceed 330 kPa, and SW_121 is in the ON position, the interlock activates and the V30 valve closes ； When the readings for PI121A and PI121B are both below 20 kPa, and SW_121 is in the ON position, an interlock action occurs and valve V30 closes ； When the bypass switch “BYPASS” of PB30 is set to OFF, VS30 can be reset only when the following conditions are met: after the reset button is pressed, the solenoid valve VS30 loses power; then the technician goes to the site and moves the handle of the solenoid valve, causing V30 to open. The conditions that caused V30 to close must return to normal, the pressure of the test gas PI95 must be greater than 20 kPa, and if the raw material gas supply is interrupted, V30 will close immediately. Additionally, if the 102J shutdown interlock is triggered, V30 will also close immediately. Note: After each interlock action, it is necessary to close the on-site valve to ensure that the pressure of the test gas is normal before the interlock can be used again. Furthermore, during operation, since the fuel pressure may reach the interlock activation level, the process should disable this interlock as appropriate before starting up; once operation is normal, the interlock can be reactivated. Interlock for furnace superheater burner 1) Purpose of the interlock: To ensure safe ignition of the superheater burner, and to guarantee that no fuel gas leaks into the furnace before ignition. During normal operation, it prevents flameout caused by excessive fuel gas pressure, as well as shutdown caused by insufficient fuel gas pressure. 2) Parameter table: Bit number, Low-Low interlock value (kPa), High-High interlock value (kPa), Normal state, Accident state. PI305A: 20, 250; PI305B: 20, 250; PI313: 20; VS30: Power-on, Power-off. 3) Logic diagram. 4) Interlock instructions: a. Interlock inputs: PI305A – fuel pressure indicator for the large burner in the superheating section of 101B; PI305B – fuel pressure indicator for the large burner in the superheating section of 101B; PI313 – pressure indicator for the check valve of the large burner in the superheating section of 101B; SW_305 – switch to activate/deactivate the interlock for PI305A and B; it is OFF when the interlock is disabled, and ON when it is active. SW_313 – switch to activate/deactivate the interlock for PI313; it is OFF when the interlock is disabled, and ON when it is active. b. Interlock outputs: VS306 – solenoid valve controlled by V306. c. Interlock operation instructions: When the bypass switch “BYPASS” for PB306 is set to OFF, the following conditions will cause VS306 to lose power, resulting in V306 and V308 being closed while V307 is opened: When both the indicators for PI305A and PI305B exceed 250 kPa, and SW_305 is in the ON position, the interlock activates, causing V306 and V308 to be closed and V307 to be opened ； When the readings of PI305A and PI305B are both below 20 kPa, and SW_305 is in the ON position, an interlock action is triggered: V306 and V308 are turned off, while V307 is turned on ； l V30 valve shutdown interlock action: When the bypass switch “BYPASS” for PB306 is set to OFF, VS306 can be reset only when the following conditions are met. After the reset button is pressed, the solenoid valve VS306 becomes energized; the process operator then goes to the site to operate the valve handle, resulting in V306 and V308 opening while V307 closes. The conditions that trigger this interlocked valve shutdown must return to normal, and the pressure of the control gas PI313 must be greater than 20 kPa. Note: After each interlock action, the on-site valve must be closed to ensure that the control gas pressure is within normal limits before the interlock can be used again. Furthermore, during operation of the machine, since the fuel pressure will be at the interlock activation level, the process should disable this interlock before starting up; once operation is normal, the interlock can be reactivated.
PI300A: 392 Pa
PI300B: 392 Pa
SI6: 500 RPM
VS300A/B: Powered, De-energized
VS301A/B: Powered, De-energized
VS302A/B: Powered, De-energized
VS304A/B: Powered, De-energized
3) Logic Diagram
4) Interlock Instructions
a. Interlock Inputs:
PI300A: Fan outlet pressure detection (original tag number: PI300)
PI300B: Fan outlet pressure detection (newly added)
SI6: Fan speed detection
HS303: Interlock activation/deactivation switch; when the switch is set to “Activated”, the interlock is active (switch in “ON” position), and when it is set to “Deactivated”, the interlock is disabled (switch in “OFF” position).
b. Interlock Outputs:
VS300A/B: 101-BU accident air damper solenoid valve
VS301A/B: 101-B accident air damper solenoid valve
VS302A/B: 101-B accident air damper solenoid valve
VS304A/B: Overheating burner ignition solenoid valve
c. Interlock Operation Instructions:
HS300: Control button for the 101-BU accident air damper; “CLOSE” indicates closing the 101-BU accident air damper, while “OPEN” indicates opening it. HS301: Control button for the accident air damper of 101-B. “CLOSE” indicates closing the accident air damper of 101-B, while “OPEN” indicates opening it. HS302: Control button for the accident air damper of 101-B. “CLOSE” indicates closing the accident air damper of 101-B, while “OPEN” indicates opening it. HS303: Overall interlock shutdown and activation. One of the following factors will trigger solenoid valves VS300A/B to lose power, causing the accident air damper 101-BU to open: When the HS303 interlock activation/shutdown switch is set to the “active” position, PI300A, PI300B, and SI6 all reach their interlock values ； When the HS303 interlock activation/deactivation switch is set to the “activated” position, it is still possible to press HS300 even if PI300A, PI300B, and SI6 do not meet the interlock conditions ； l When the HS303 interlock activation/deactivation switch is set to the \"deactivated\" position, HS300 can also be forced to be activated ； One of the following factors will trigger solenoid valves VS301A/B to lose power, causing the accident air damper 101-B to open: When the HS303 interlock activation/deactivation switch is set to the “active” position, PI300A, PI300B, and SI6 all reach their interlock values ； When the HS303 interlock activation/deactivation switch is set to the \"active\" position, it is still possible to press HS301 even if PI300A, PI300B, and SI6 do not meet the interlock conditions ； l When the HS303 interlock enable/disable switch is set to the “disabled” position, HS301 can also be forced to be pressed ； One of the following factors will trigger solenoid valves VS302A/B to lose power, causing the accident air damper 101-B to open: when the HS303 interlock activation/deactivation switch is set to the “activated” position, PI300A, PI300B, and SI6 all reach their interlock values ； When the HS303 interlock activation/deactivation switch is set to the \"activated\" position, HS302 can also be pressed even if PI300A, PI300B, and SI6 do not meet the interlock conditions ； l When the HS303 interlock enable/disable switch is set to the \"Disable\" position, HS302 can also be forced to be pressed ； Interlock for Process Condensate Stripping Tower 150-E 1) Purpose of the interlock: To ensure the recovery of qualified process condensate; when the conductivity of the process condensate at the outlet of 150E is high, the interlock activates to discharge the condensate. 2) Parameter table: Bit number, interlock value, normal state, accident state. AI10: 200μs/cm; XY10A: energized, de-energized; XY10B: de-energized, energized. 3) Logic diagram. 4) Interlock description: a. Interlock input: AI10 – conductivity of the process condensate at the bottom of Tower 150-E. b. Interlock outputs: XY10A to the solenoid valve connected to AV10A; XY10B to the solenoid valve connected to AV10B. c. Interlock operation description: One of the following factors will trigger the solenoid valves XY10A and XY10B – when XY10A is de-energized, AV10A opens and the condensate is discharged; when XY10B is energized, AV10B closes. This occurs when PBAV10 is in the “operational” state and AI10 reaches the interlock value ； l Press the soft button PBAV10 ； Interlock for fuel gas at the top burner of Section 1 furnace: 1) Purpose of the interlock – To ensure safe ignition of the top burner in Section 1 furnace, and to guarantee that no fuel gas leaks into the furnace chamber before ignition. During normal operation, it prevents flameout caused by excessive fuel gas pressure, as well as shutdown caused by insufficient fuel gas pressure. 2) Parameter table: Bit number – Low/low interlock value (kPa), High/high interlock value (kPa); Normal state, Accident state. PI121A: 20, 330; PI121B: 20, 330; PI95: 20; VS30: De-energized/ Energized. 3) Logic diagram. 4) Interlock instructions: a. Interlock inputs: PI121A – Fuel pressure indicator after V30 valve; PI121B – Fuel pressure indicator after V30 valve; PI95 – Pressure indicator of the check gas; SW_121 – Switch for enabling/disabling the interlocks of PI121A and B; it is OFF when the interlocks are disabled, and ON when they are enabled. SW_95 – Switch for enabling/disabling the interlock of PI95; it is OFF when the interlock is disabled, and ON when it is enabled. b. Interlock outputs: VS30 – Solenoid valve connected to V30; another output is connected to the interlock PB306, which shuts off the fuel gas supply to the top burner of 101B. c. Interlock operation instructions: When the bypass switch “BYPASS” for PB30 is OFF, the following conditions will cause VS30 to become energized and the V30 valve to close: When both the indicators PI121A and PI121B exceed 330 kPa, and SW_121 is in the ON position, the interlock activates and the V30 valve closes ； When the readings for PI121A and PI121B are both below 20 kPa, and SW_121 is in the ON position, an interlock action occurs and valve V30 closes ； When the bypass switch “BYPASS” of PB30 is set to OFF, VS30 can be reset only when the following conditions are met: after the reset button is pressed, the solenoid valve VS30 loses power; then the technician goes to the site and moves the handle of the solenoid valve, causing V30 to open. The conditions that caused V30 to close must return to normal, the pressure of the test gas PI95 must be greater than 20 kPa, and if the raw material gas supply is interrupted, V30 will close immediately. Additionally, if the 102J shutdown interlock is triggered, V30 will also close immediately. Note: After each interlock action, it is necessary to close the on-site valve to ensure that the pressure of the test gas is normal before the interlock can be used again. Furthermore, during operation, since the fuel pressure may reach the interlock activation level, the process should disable this interlock as appropriate before starting up; once operation is normal, the interlock can be reactivated. Interlock for furnace superheater burner 1) Purpose of the interlock: To ensure safe ignition of the superheater burner, and to guarantee that no fuel gas leaks into the furnace before ignition. During normal operation, it prevents flameout caused by excessive fuel gas pressure, as well as shutdown caused by insufficient fuel gas pressure. 2) Parameter table: Bit number, Low-Low interlock value (kPa), High-High interlock value (kPa), Normal state, Accident state. PI305A: 20, 250; PI305B: 20, 250; PI313: 20; VS30: Power-on, Power-off. 3) Logic diagram. 4) Interlock instructions: a. Interlock inputs: PI305A – fuel pressure indicator for the large burner in the superheating section of 101B; PI305B – fuel pressure indicator for the large burner in the superheating section of 101B; PI313 – pressure indicator for the check valve of the large burner in the superheating section of 101B; SW_305 – switch to activate/deactivate the interlock for PI305A and B; it is OFF when the interlock is disabled, and ON when it is active. SW_313 – switch to activate/deactivate the interlock for PI313; it is OFF when the interlock is disabled, and ON when it is active. b. Interlock outputs: VS306 – solenoid valve controlled by V306. c. Interlock operation instructions: When the bypass switch “BYPASS” for PB306 is set to OFF, the following conditions will cause VS306 to lose power, resulting in V306 and V308 being closed while V307 is opened: When both the indicators for PI305A and PI305B exceed 250 kPa, and SW_305 is in the ON position, the interlock activates, causing V306 and V308 to be closed and V307 to be opened ； When the readings of PI305A and PI305B are both below 20 kPa, and SW_305 is in the ON position, an interlock action is triggered: V306 and V308 are turned off, while V307 is turned on ； l V30 valve shutdown interlock action: When the bypass switch “BYPASS” for PB306 is set to OFF, VS306 can be reset only when the following conditions are met. After the reset button is pressed, the solenoid valve VS306 becomes energized; the process operator then goes to the site to operate the valve handle, resulting in V306 and V308 opening while V307 closes. The conditions that trigger this interlocked valve shutdown must return to normal, and the pressure of the control gas PI313 must be greater than 20 kPa. Note: After each interlock action, the on-site valve must be closed to ensure that the control gas pressure is within normal limits before the interlock can be used again. Furthermore, during operation of the machine, since the fuel pressure will be at the interlock activation level, the process should disable this interlock before starting up; once operation is normal, the interlock can be reactivated.
Our optimization control systems mainly include the following: 1. Hydrogen-to-nitrogen ratio; 2. Water-to-carbon ratio; 3. Temperature at the outlet of the first-stage furnace; 4. The three-injection method for feeding water into the boiler. As those of us who specialize in instrument automation are not entirely familiar with the details of how these systems are designed, we feel that they are not very effective, and there are many problems. The main issue is that some domestically produced control valves suffer from severe internal leakage, resulting in low reliability when in use. Cangzhou Dahuahua has done an excellent job in this area; we also adopted its model, but not many systems have been put into use so far. The few people who were initially working on this project were recruited by Ordos United Chemicals. Hehe! It is recommended that you check the Instrument Automation section – you will surely find a satisfactory answer there!