Automatic ignition control system and method for hydrochloric acid synthesis furnace

Abstract

The invention discloses an automatic ignition control system and method for a hydrochloric acid synthesis furnace, belongs to the field of automatic ignition control, and aims to solve the problems that in the prior art, an ignition control system is single in control mode and poor in safety, seamless switching of remote PLC control, remote DCS control and on-site ignition control is achieved through a control mode switching device, and the safety of the ignition control system is improved. The three modes are unified in function and synchronous in state feedback, so that the intelligent requirement of centralized management and control of a control room is met, and the flexibility of field emergency operation is kept; and secondly, an operator does not need to make close contact with a high-temperature and high-pressure area of the synthetic furnace and a flammable and explosive gas environment in a remote control mode, personal safety risks are avoided from an operation scene, and the overall safety performance is improved.

Description

Technical Field

[0001] This invention relates to the field of automatic ignition control technology, and in particular to an automatic ignition control system and method for a hydrochloric acid synthesis furnace. Background Technology

[0002] Hydrochloric acid synthesis furnaces are core equipment in the chemical industry for hydrochloric acid production. The ignition process, as a crucial pre-reaction step, directly determines subsequent production efficiency, equipment stability, and operator safety through its operational safety, process reliability, and degree of automation. With the modern chemical industry's transformation towards intelligent, safe, and efficient processes, traditional hydrochloric acid synthesis furnace ignition devices are no longer adequate for current production demands.

[0003] Currently, most hydrochloric acid synthesis furnaces adopt traditional manual control or simple electrical control modes, which have the following problems: Most traditional devices only support on-site manual operation. Operators need to be in close contact with the high-temperature and high-pressure synthesis furnace area, facing the safety risk of leakage of flammable and explosive gases such as hydrogen and chlorine. Some devices with remote control functions have incompatible logic for switching between remote and local control modes, and the status feedback signal is broken, resulting in the information in the control room and the field being out of sync, which can easily lead to misoperation. The entire ignition process requires manual intervention in several key stages, such as manually judging the air replenishment time in the synthesis furnace, manually starting and stopping the purging process, manually controlling the gas circuit valves, and visually observing the flame ignition status. This is not only cumbersome and inefficient, but also prone to ignition failure due to human misjudgment (such as insufficient air replenishment time) or operational errors (such as incorrect valve switching sequence), and may even lead to safety accidents such as gas leaks, combustion, and explosions.

[0004] Therefore, we propose an automatic ignition control system and method for hydrochloric acid synthesis furnace. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic ignition control system and method for hydrochloric acid synthesis furnace, which solves the problems of single control mode and poor safety in the current ignition control system in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an automatic ignition control system for a hydrochloric acid synthesis furnace, comprising: The PLC control unit is used to receive commands from the DCS system and lead the entire ignition process, output status signals to the DCS system, and can achieve multi-level flame adjustment. The DCS interaction module is used for the transmission of ignition permission and stop commands between the DCS system and the PLC control unit, as well as the feedback of status signals such as ignition, ignition failure, valve status, and flame detector signals. A control mode switching device is used to switch between remote control mode and local control module; The gas control unit includes a gas control cabinet, four gas source interfaces and supporting control components. The four gas sources are hydrogen, air, nitrogen and instrument gas. The control components include a hydrogen control valve, an air control valve, a nitrogen control valve, a pressure reducing valve, a flow regulating device and a pressure detection interlock component. The ignition execution unit includes an ignition gun and a transformer, wherein the transformer provides the voltage required for ignition to the ignition gun; The flame detection unit includes a flame detector, which is used to detect the flame status and flame temperature in real time. After successful ignition, it detects the temperature of the inner wall of the synthesis furnace and transmits the detection signal to the PLC control unit. The interlock protection unit is used to automatically perform valve closing and nitrogen purging interlock actions in the event of ignition failure or abnormality. The PLC control unit is electrically connected to the DCS interaction module, control mode switching device, gas control unit, ignition execution unit, flame detection unit, and interlock protection unit to realize intelligent automatic control of the ignition process.

[0007] Furthermore, the various air sources of the pneumatic control unit meet the following pressure requirements: Instrument air pressure: 0.4 MPa < P < 0.6 MPa; Hydrogen pressure: 0.04 MPa < P < 0.15 MPa; Air pressure: 0.1 MPa < P < 0.2 MPa; Nitrogen pressure: 0.1 MPa < P < 0.2 MPa; All gas source interfaces are G1 / 2.

[0008] Furthermore, the pressure detection interlocking components include nitrogen pressure interlocking valves SV400-1 and SV400-2. When the nitrogen pressure is ≥120 kPa, SV400-1 and SV400-2 automatically open; when the nitrogen pressure is <100 kPa, SV400-1 and SV400-2 automatically close.

[0009] Furthermore, the pressure reducing valve includes a hydrogen pressure reducing valve, an air pressure reducing valve, and a nitrogen pressure reducing valve, wherein the output pressure of the air pressure reducing valve and the nitrogen pressure reducing valve is 0.15 MPa, and the output pressure of the hydrogen pressure reducing valve is ≥50 kPa.

[0010] Furthermore, the remote control mode includes PLC cabinet remote control and DCS remote control. The corresponding operation panels are respectively equipped with an ignition permission indicator, a purge / ignition status indicator, a purge button, a reset button, and a stop button. The local operation panel configuration corresponding to the local control mode is consistent with the functions of the remote operation panel.

[0011] Furthermore, the nitrogen flow rate regulating device is set to a nitrogen flow rate ≥3m³ / h and a dynamic pressure ≥0.05Mpa, which is always greater than the pressure inside the synthesis furnace; when the air regulating valve is at its maximum opening, the air flow rate is ≥10Nm³ / h and the dynamic pressure is ≥0.05Mpa; during ignition, the hydrogen flow rate is ≥5m³ / h and the dynamic pressure is ≥50Kpa.

[0012] This invention also provides another technical solution: an automatic ignition control method for a hydrochloric acid synthesis furnace, comprising the following steps: S1: Control mode switching, the system is switched to remote control mode or local control mode through the control mode switching device; S2: Ignition permission condition confirmation. After the operator determines that the air replenishment time in the synthesis furnace is greater than 10 minutes, the DCS system sends an ignition permission command to the PLC control unit. After receiving the command, the PLC control unit lights up the ignition permission indicator light. S3: Pre-ignition air purging. Press the purging button to start the purging. The PLC control unit controls the nitrogen control valve to close, opens the air control valve, and opens the air regulating valve to the maximum set value to perform air purging. The purging time is 10 seconds. The purging indicator light flashes during the purging process and stays on after the purging is completed. S4: Ignition execution. After purging, the air regulating valve is adjusted to the lowest value, the PLC control unit starts the built-in timer, and when the time is up, the control transformer starts discharging, and the ignition gun performs ignition. S5: Flame detection and result processing. The flame detection unit detects the flame status in real time and feeds it back to the PLC control unit. If the flame is successfully ignited within 40 seconds, the PLC control unit controls the discharge to be turned off. After a delay, the subsequent gas control is executed, and the ignition signal is fed back to the DCS system. If no flame is detected within 40 seconds, it is determined to be an ignition failure, and the interlock protection unit will automatically start: close the hydrogen control valve, air control valve, air regulating valve and discharge, open the nitrogen control valve to purge the burner, and after reset, the ignition process can be re-executed, while feeding back the ignition failure signal to the DCS system. S6: Ignition Stop and Pressure Holding. When the ignition stop button is pressed, the PLC control unit controls the closure of the hydrogen control valve and the air control valve, opens the nitrogen control valve for purging and maintains the nitrogen flow rate, and ensures that the outlet pressure of the pressure reducing valve is always greater than the pressure inside the synthesis furnace. At the same time, the stop status signal is fed back to the DCS system.

[0013] Furthermore, in S5, after successful ignition, when the central flame of the synthesis unit is ignited, the corresponding flame status light remains on, the chlorine gas valve start button is activated, and the ignition signal is detected in sequence. If the signal is valid, the ignition process sequence is maintained; if the signal is invalid, the interlock protection unit is activated.

[0014] Furthermore, after ignition stops, the nitrogen control valve remains open, and the nitrogen flow rate is adjusted to 3 m³ / h via the pressure reducing valve, while the nitrogen pressure reducing valve remains open at all times.

[0015] Furthermore, in S5, before re-ignition after an ignition failure, the ignition device must be reset using the reset button on the control panel to ensure that the ignition process of steps S3-S5 is executed again.

[0016] Compared with the prior art, the beneficial effects of the present invention are: The present invention proposes an automatic ignition control system and method for a hydrochloric acid synthesis furnace. In the prior art, the ignition control system has a single control mode and poor safety. However, the present invention achieves seamless switching between remote PLC control, remote DCS control and local ignition control through a control mode switching device. The three modes have unified functions and synchronized status feedback, which not only meets the intelligent requirements of centralized control in the control room, but also retains the flexibility of on-site emergency operation. Secondly, the remote control mode eliminates the need for operators to have close contact with the high-temperature and high-pressure areas of the synthesis furnace and the flammable and explosive gas environment, thus avoiding personal safety risks from the perspective of the operation scenario and improving the overall safety performance and intelligence level. In addition, relying on the PLC control unit and DCS interaction module, the entire process of ignition permission confirmation, air purging, high-pressure ignition, flame detection, gas path adjustment, and pressure holding is automated, eliminating the need for manual judgment of air replenishment time, manual control of valve opening and closing, or visual observation of flame status, thus improving operational accuracy. Attached Figure Description

[0017] Figure 1 This is a flowchart of the overall program of the automatic ignition control system and method for hydrochloric acid synthesis furnace of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To address the technical problems of existing ignition control systems, such as their single control mode and poor safety, Figure 1 As shown, the following preferred technical solutions are provided: An automatic ignition control system for a hydrochloric acid synthesis furnace includes: The PLC control unit is used to receive commands from the DCS system and lead the entire ignition process, output status signals to the DCS system, and can achieve multi-level flame adjustment. The DCS interaction module is used for the transmission of ignition permission and stop commands between the DCS system and the PLC control unit, as well as the feedback of status signals such as ignition, ignition failure, valve status, and flame detector signals. A control mode switching device is used to switch between remote control mode and local control module; The gas control unit includes a gas control cabinet, four gas source interfaces and supporting control components. The four gas sources are hydrogen, air, nitrogen and instrument gas. The control components include a hydrogen control valve, an air control valve, a nitrogen control valve, a pressure reducing valve, a flow regulating device and a pressure detection interlock component. The ignition execution unit includes an ignition gun and a transformer, wherein the transformer provides the voltage required for ignition to the ignition gun; The flame detection unit includes a flame detector, which is used to detect the flame status and flame temperature in real time. After successful ignition, it detects the temperature of the inner wall of the synthesis furnace and transmits the detection signal to the PLC control unit. The interlock protection unit is used to automatically perform valve closing and nitrogen purging interlock actions in the event of ignition failure or abnormality. The PLC control unit is electrically connected to the DCS interaction module, control mode switching device, gas control unit, ignition execution unit, flame detection unit, and interlock protection unit to realize intelligent automatic control of the ignition process.

[0020] The air sources of the pneumatic control unit meet the following pressure requirements: Instrument air pressure: 0.4 MPa < P < 0.6 MPa; Hydrogen pressure: 0.04 MPa < P < 0.15 MPa; Air pressure: 0.1 MPa < P < 0.2 MPa; Nitrogen pressure: 0.1 MPa < P < 0.2 MPa; All gas source interfaces are G1 / 2.

[0021] The pressure detection interlock components include nitrogen pressure interlock valves SV400-1 and SV400-2. When the nitrogen pressure is ≥120 kPa, SV400-1 and SV400-2 will automatically open; when the nitrogen pressure is <100 kPa, SV400-1 and SV400-2 will automatically close.

[0022] The pressure reducing valves include hydrogen pressure reducing valve (PCV100), air pressure reducing valve (PCV200), and nitrogen pressure reducing valve (PCV300), wherein the output pressure of the air pressure reducing valve and the nitrogen pressure reducing valve is 0.15 MPa, and the output pressure of the hydrogen pressure reducing valve is ≥50 kPa.

[0023] The remote control mode includes PLC cabinet remote control and DCS remote control. The corresponding operation panels are respectively equipped with ignition permission indicator, purge / ignition status indicator, purge button, reset button and stop button. The local control mode has the same configuration and function as the remote operation panel.

[0024] The nitrogen flow rate regulating device is set to a nitrogen flow rate ≥3m³ / h and a dynamic pressure ≥0.05Mpa, which is always greater than the pressure inside the synthesis furnace; when the air regulating valve (PV200) is at its maximum opening, the air flow rate is ≥10Nm³ / h and the dynamic pressure is ≥0.05Mpa; during ignition, the hydrogen flow rate is ≥5m³ / h and the dynamic pressure is ≥50Kpa.

[0025] This invention also discloses another technical solution, an automatic ignition control method for a hydrochloric acid synthesis furnace, comprising the following steps: S1: Control mode switching, the system is switched to remote control mode or local control mode through the control mode switching device; S2: Ignition permission condition confirmation. After the operator determines that the air replenishment time in the synthesis furnace is greater than 10 minutes, the DCS system sends an ignition permission command to the PLC control unit. After receiving the command, the PLC control unit lights up the ignition permission indicator light. S3: Pre-ignition air purging. Press the purging button to start the purging process. The PLC control unit will close the nitrogen control valve (EVD300), open the air control valve (EVD200), and open the air regulating valve (PV200) to the maximum set value to perform air purging. The purging time is 10 seconds. The purging indicator light will flash during the purging process and will remain on after the purging is completed. S4: Ignition execution. After purging, the air regulating valve (PV200) is adjusted to a smaller value, the PLC control unit starts the built-in timer, and when the time is up, the control transformer (BA500) starts discharging, and the ignition gun performs ignition. S5: Flame detection and result processing. The flame detection unit detects the flame status in real time and feeds it back to the PLC control unit. If the flame is successfully ignited within 40 seconds (ignition status light is always on), the PLC control unit controls the discharge to be turned off (BA500). After a delay, the subsequent gas control is executed, and the ignition signal is fed back to the DCS system. If no flame is detected within 40 seconds (ignition status light is not constantly on), it is determined to be an ignition failure, and the interlock protection unit will automatically start: close the hydrogen control valve (EVD100), air control valve (EVD200), air regulating valve (PV200) and discharge (BA500), open the nitrogen control valve (EVD300) to purge the burner, and after reset, the ignition process can be re-executed, while the ignition failure signal is fed back to the DCS system; S6: Ignition Stop and Pressure Holding. When the ignition stop button is pressed, the PLC control unit controls the closure of the hydrogen control valve (EVD100) and the air control valve (EVD200), and opens the nitrogen control valve (EVD300) to purge and maintain the nitrogen flow. The outlet pressure of the pressure reducing valve is always greater than the pressure inside the synthesis furnace, and at the same time, the stop status signal is fed back to the DCS system.

[0026] In S5, after successful ignition, when the central flame of the synthesis unit is ignited, the corresponding flame status light remains on. The chlorine gas valve start button is activated, and the ignition signal is detected in sequence. If the signal is valid, the ignition process sequence is maintained; if the signal is invalid, the interlock protection unit is activated.

[0027] After ignition stops, the nitrogen control valve (EVD300) remains open, and the nitrogen flow rate is adjusted to 3m³ / h via the pressure reducing valve, while the nitrogen pressure reducing valve (PCV300) remains open.

[0028] In S5, before re-ignition after an ignition failure, the ignition device must be reset using the reset button on the control panel to ensure that the ignition process of steps S3-S5 is re-executed.

[0029] In remote control mode, the buttons corresponding to the PLC cabinet remote control include S-21 ignition and purge button, S-22 chlorine valve start button, S-23 ignition gun stop button, and S-24 ignition reset / main stop button. The indicator lights include L-21 ignition enable light, L-22 purge / ignition status light, and L-23 flame status light. The buttons corresponding to the DCS remote control include S-31 ignition and purge button, S-32 chlorine valve start button, S-33 ignition gun stop button, and S-34 ignition reset / main stop button. The indicator lights include L-31 ignition enable light, L-32 purge / ignition status light, and L-33 flame status light.

[0030] In local control mode, the buttons on the control panel include S-11 gun ignition and purging button, S-12 chlorine valve start button, S-13 ignition gun stop button, and S-14 ignition reset / main stop button. The indicator lights include L-11 ignition enable light, L-12 purging / ignition status light, and L-13 flame status light.

[0031] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A hydrochloric acid synthesis furnace automatic ignition control system, characterized by, Comprise: PLC control unit for receiving the instruction of DCS system and leading the whole ignition process, outputting state signal to DCS system, and realizing multi-stage flame regulation; DCS interaction module for transmitting ignition permission and stop instruction between DCS system and PLC control unit, and feeding back state signal of ignition, ignition failure, valve state and flame detector signal; Control mode switching device for switching remote control mode and local control mode; Pneumatic control unit comprising pneumatic control cabinet, four-way gas source interface and matching control components, the four-way gas source is hydrogen, air, nitrogen and instrument air, the control components comprise hydrogen control valve, air control valve, nitrogen control valve, pressure reducing valve, flow regulating device and pressure detection interlocking component; Ignition execution unit comprising ignition gun and transformer, the transformer provides voltage required by ignition gun; Flame detection unit comprising flame detector for detecting flame state and flame temperature in real time, detecting temperature of inner wall of synthesis furnace after successful ignition, and transmitting detection signal to PLC control unit; Interlocking protection unit for automatically executing interlocking action of valve closing and nitrogen purging when ignition fails or is abnormal; The PLC control unit is electrically connected with DCS interaction module, control mode switching device, pneumatic control unit, ignition execution unit, flame detection unit and interlocking protection unit, realizing intelligent automatic control of ignition process.

2. A hydrochloric acid synthesis furnace automatic ignition control system as claimed in claim 1, characterized in that: Each gas source of pneumatic control unit meets the following pressure requirements: Instrument air pressure: 0.4Mpa Hydrogen pressure: 0.04Mpa Air pressure: 0.1Mpa Nitrogen pressure: 0.1Mpa The specification of each gas source interface is G1 / 2.

3. A hydrochloric acid synthesis furnace automatic ignition control system as claimed in claim 2, characterized in that: The pressure detection interlocking component comprises nitrogen pressure interlocking valve SV400-1 and SV400-2, when nitrogen pressure is greater than or equal to 120Kpa, SV400-1 and SV400-2 are automatically opened, when nitrogen pressure is less than 100Kpa, SV400-1 and SV400-2 are automatically closed.

4. The automatic ignition control system for a hydrochloric acid synthesis furnace according to claim 3, characterized by: The pressure reducing valve comprises hydrogen pressure reducing valve, air pressure reducing valve and nitrogen pressure reducing valve, the output pressure of air pressure reducing valve and nitrogen pressure reducing valve is 0.15Mpa, the output pressure of hydrogen pressure reducing valve is greater than or equal to 50Kpa.

5. A hydrochloric acid synthesis furnace automatic ignition control system as claimed in claim 4, characterized in that: The remote control mode comprises PLC cabinet remote control and DCS remote control, the corresponding operation panel is provided with ignition permission indicator, purging / ignition state indicator, purging button, reset button and stop button, the local control mode corresponds to local operation panel with the same function as remote operation panel.

6. A hydrochloric acid synthesis furnace automatic ignition control system as claimed in claim 5, characterized in that: The nitrogen flow regulating device sets nitrogen flow to be greater than or equal to 3m³ / h, dynamic pressure to be greater than or equal to 0.05Mpa and always greater than the pressure in synthesis furnace, the maximum opening degree of air regulating valve is greater than or equal to 10Nm³ / h, dynamic pressure is greater than or equal to 0.05Mpa, hydrogen flow is greater than or equal to 5m³ / h during ignition, dynamic pressure is greater than or equal to 50Kpa.

7. A method of automatic ignition control of a hydrochloric acid synthesis furnace based on the automatic ignition control system of a hydrochloric acid synthesis furnace according to any one of claims 1 to 6, characterized by Comprise the following steps: S1: control mode switching, switching the system to remote control mode or local control mode through control mode switching device; S2: Ignition permission condition confirmation, after the operator judges that the air replenishment time in the synthesis furnace is greater than 10 minutes, the DCS system sends an ignition permission instruction to the PLC control unit, and the PLC control unit lights up the ignition permission indicator after receiving the instruction; S3: Air purging before ignition, start the purging button, the PLC control unit controls to close the nitrogen control valve, open the air control valve and adjust the air valve to the maximum set value, and perform air purging, the purging time is 10S, the purging indicator flashes during purging, and the purging indicator is always on after purging is completed; S4: Ignition execution, after purging is completed, the air regulating valve is adjusted to a smaller value, the PLC control unit starts the built-in timer, and when the time is up, the transformer is started to discharge, and the ignition gun executes ignition; S5: Flame detection and result processing, the flame detection unit detects the flame state in real time and feeds back to the PLC control unit: if the flame is successfully ignited within 40S, the PLC control unit controls to close the discharge, and after a delay, the subsequent gas control is executed, and the ignition signal is fed back to the DCS system; If the flame is not detected within 40S, it is determined that the ignition fails, and the interlock protection unit automatically starts: closes the hydrogen control valve, air control valve, air regulating valve and discharge, and opens the nitrogen control valve to purge the burner, and after reset, the ignition process can be executed again, and the ignition failure signal is fed back to the DCS system; S6: Ignition stop and pressure maintenance, start the ignition stop button, the PLC control unit controls to close the hydrogen control valve and air control valve, and opens the nitrogen control valve for purging and maintains the nitrogen flow, the outlet pressure of the pressure reducing valve is always greater than the pressure in the synthesis furnace, and the stop state signal is fed back to the DCS system.

8. The method of claim 7, wherein the method further comprises: determining a temperature of the hydrochloric acid synthesis reactor; and determining a temperature of the hydrochloric acid synthesis reactor. In S5, after successful ignition, when the center flame of the synthesis device is ignited, the corresponding flame state lamp is always on, the chlorine small valve start button is started, the ignition signal is detected in time, and the ignition process sequence is maintained when the signal is valid, and the interlock protection unit is started when the signal is invalid.

9. The method of claim 8, wherein the method further comprises: determining a temperature of the hydrochloric acid synthesis reactor; and determining a temperature of the hydrochloric acid synthesis reactor. After ignition is stopped, the nitrogen control valve is always kept open, the nitrogen flow is adjusted to 3m³ / h through the pressure reducing valve, and the nitrogen pressure reducing valve is always kept open.

10. The automatic ignition control method for a hydrochloric acid synthesis furnace as described in claim 9, characterized in that: In S5, before re-ignition after ignition failure, the ignition device needs to be reset through the reset button on the operation panel to ensure that the ignition process of steps S3-S5 is executed again.

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