Dry quenching mother tube type boiler system and control method thereof

Abstract

The invention relates to a dry quenching mother tube type boiler system, in particular to a dry quenching mother tube type boiler system and a control method thereof, which are used for controlling the dry quenching mother tube type boiler system. Comprising the steps of monitoring the state of a feed pump in the system to obtain monitoring information; judging the shutdown number of the feed pump according to the monitoring information; and the dry quenching main tube type boiler system is regulated and controlled according to the shutdown number of the water feeding pumps. The automatic interlocking coke discharging device can automatically interlock to stop coke discharging operation after the shutdown of a boiler feed pump is automatically detected, solves the problem of manual coke discharging operation stopping, reduces circulating air volume and improves boiler feed water quantity through automatic interlocking, balances the relation between evaporation capacity and feed water quantity at the lowest operation load, realizes low-load operation, automatically interlocks nitrogen filling and reduces air introduction quantity, and improves the coke discharging efficiency. It is guaranteed that combustible components in the dry quenching furnace are within the control range, and the operation safety risk of the boiler is effectively solved.

Description

Technical Field

[0001] The invention relates to a dry coke quenching mother tube type boiler system, in particular to a dry coke quenching mother tube type boiler system and a control method thereof. Background Art

[0002] At present, the domestic coking plants use three dry coke quenching and four boilers. The quenching mother tube boiler has automatic control of feed water pump when running at low load, the quenching mother tube boiler has automatic control when running at low load, and the pipelines are interconnected. When three feed water pumps and coke quenching mother tube boiler low load operation automatic controls are running at the same time, they can meet the normal water supply of the three boilers' coke quenching mother tube boiler low load operation automatic controls; if one or two of the feed water pumps and coke quenching mother tube boiler low load operation automatic controls suddenly fail and stop due to external reasons, if the loads of the three dry coke quenching boilers cannot be reduced in time at this time, the remaining one or two feed water pumps and coke quenching mother tube boiler low load operation automatic controls will supply water to the three boilers' coke quenching mother tube boiler low load operation automatic controls at the same time, and the water supply of the feed water pumps and coke quenching mother tube boiler low load operation automatic controls will be far from meeting the evaporation volume of the boilers' coke quenching mother tube boiler low load operation automatic controls, which will cause a process accident of water shortage of the boilers' coke quenching mother tube boiler low load operation automatic controls in a short period of time, and may even cause serious production accidents such as pipe burst of the boilers' coke quenching mother tube boiler low load operation automatic controls.

[0003] In response to the above reasons, the following measures have been taken accordingly:

[0004] 1. Manually stop the CDQ and coke discharge operations at three reactors and keep the load speed decreasing slowly.

[0005] 2. Manual operation reduces the circulating fan speed to quench the coke main tube boiler at low load and automatically controls the speed to reduce the circulating air volume.

[0006] 3. Manually operate the boiler to quench the coke. Main tube boilers operate at low loads, automatically controlling various valves to ensure a balance between evaporation and water supply, and operating at the lowest load. 4. Manually inject nitrogen and reduce air intake to ensure that the gas composition in the furnace is within a safe range. These measures can solve the problem, but they are labor-intensive, pose high operational safety risks, and require long operation times. Repeatedly implementing these measures does not fundamentally free up labor or improve efficiency, and they also pose operational safety concerns. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to manually stop the three dry coke quenching and coke discharge operations and keep the load speed slowly decreasing.

[0008] The above technical problems are solved by the following technical solutions: The present invention proposes a low-load operation automatic control method for a dry coke quenching mother tube boiler, which is used to control a dry coke quenching mother tube boiler system; comprising:

[0009] Function of monitoring the status of water supply pump in the system to obtain monitoring information;

[0010] Determine the number of water supply pump shutdowns based on monitoring information;

[0011] The CDQ mother tube boiler system is regulated according to the number of feed water pump shutdowns.

[0012] In a preferred embodiment of the automatic control method for low-load operation of the CDQ mother tube boiler of the present invention: when the number of shutdown units is one, the total water supply and circulating air volume required by the boilers in the system are calculated, and the circulating air volume and total water supply of each CDQ furnace are adjusted and reduced according to the calculated values, and the CDQ furnace coke discharge operation is simultaneously stopped by interlocking.

[0013] In a preferred embodiment of the automatic control method for low-load operation of the dry quenching mother tube boiler of the present invention: when the number of shutdown units is two, the total water supply required by the boilers in the system and the circulating air volume of each dry quenching furnace are calculated, and the circulating air volume and total water supply of the three dry quenching furnaces are adjusted according to the calculated values. At the same time, an interlock is implemented to stop the dry quenching furnace from discharging coke, and an interlock is implemented to open the inert gas charging valve to inject inert gas into the dry quenching furnace to dilute the concentration of combustible gas.

[0014] In a preferred embodiment of the low-load operation automatic control method of the CDQ mother tube boiler of the present invention: the inert gas is nitrogen, the inert gas pressure requirement is ≥0.4-0.7 MPa, and each injection time is 10 minutes.

[0015] In a preferred embodiment of the automatic control method for low-load operation of the dry coke quenching mother tube boiler of the present invention: the combustible gases are carbon monoxide CO, carbon dioxide CO2, oxygen O2 and hydrogen H2, and the control concentration range is carbon monoxide <6%, carbon dioxide <6% to 15%, oxygen <1%, hydrogen <3%, and nitrogen is controlled at 72% to 83%.

[0016] In a preferred embodiment of the automatic control method for low-load operation of a dry coke quenching mother tube boiler described in the present invention: a program block written based on a PLC control system is used to calculate the total water supply required by the boilers in the system and the circulating air volume of each dry coke quenching furnace. The calculation parameters involved include main steam flow, main steam pressure, drum liquid level, boiler feed water flow, drum pressure, boiler inlet temperature, boiler feed water pump shutdown signal, circulating air volume, circulating air duct gas composition, and dry coke quenching furnace material level.

[0017] The present invention also proposes a dry quenching mother tube boiler system, which is controlled by the above-mentioned dry quenching mother tube boiler low-load operation automatic control method; comprising:

[0018] CDQ furnace;

[0019] Boiler, connected to CDQ furnace;

[0020] Water supply module, used to supply water to the boiler;

[0021] A circulating fan is provided between the dry quenching furnace and the boiler.

[0022] In a preferred embodiment of the CDQ mother tube boiler system of the present invention, each CDQ furnace is equipped with a coke discharge module.

[0023] In a preferred embodiment of the CDQ mother tube boiler system of the present invention: the water supply module includes a water supply pump, a water supply mother pipe connected to the water supply pump, and a regulating valve provided between the water supply mother pipe and the boiler.

[0024] In a preferred embodiment of the CDQ mother tube boiler system of the present invention, an inert gas charging valve is further provided between the CDQ furnace and the boiler.

[0025] The beneficial effects of the present invention are: it can automatically detect the shutdown of the boiler feed water pump and automatically interlock to stop the coke removal operation, thereby solving the problem of manually stopping the coke removal operation; it can automatically interlock to reduce the circulating air volume and increase the boiler feed water volume, and balance the relationship between the evaporation volume and the feed water volume at the lowest operating load to achieve low-load operation; it can automatically interlock to inject nitrogen and reduce the air introduction volume to ensure that the combustible components in the dry quenching furnace are within the control range, thereby effectively solving the safety risks of boiler operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Among them:

[0027] Figure 1 The structural diagram of the CDQ mother tube boiler system is shown;

[0028] Figure 2 The present invention shows a flow chart of an automatic control method for low-load operation of a CDQ mother tube boiler. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0030] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as the meanings of the terms and the overall description of the present invention.

[0031] Reference Figure 1 This embodiment provides a method for automatically controlling a dry coke quenching mother tube boiler at low load, including a control device for controlling a dry coke quenching mother tube boiler system; and the method includes the following steps:

[0032] S1, monitoring the status of the water supply pump 301 in the system to obtain monitoring information;

[0033] There are multiple feed water pumps 301 in the CDQ mother tube boiler system. The status of the feed water pump 301 in the monitoring system is mainly to monitor whether the feed water pump 301 has a shutdown problem. It mainly introduces parameters such as the operating signals and current values ​​of important equipment such as the feed water pump 301 and the circulating fan 400, and outputs command signals through control logic judgment through filtering and multiple selection.

[0034] S2. Determine the number of water supply pumps 301 that have been shut down based on the monitoring information;

[0035] Specifically, the number of shutdowns of the water supply pump 301 is determined by using a command signal obtained through an operation signal and a current value.

[0036] S3. Regulating the CDQ mother tube boiler system according to the number of shutdowns of the feed water pump 301.

[0037] When the number of shutdown units is 1, the total water supply and circulating air volume required by the boiler 200 in the system are calculated, and the circulating air volume and total water supply of each CDQ furnace 100 are adjusted and reduced according to the calculated values. At the same time, the coke discharge operation of the CDQ furnace 100 is stopped by interlock. Through adjustment, the normal production of CDQ can be ensured without being affected, and the low-load operation of the boiler 200 can be maintained for a short period of time.

[0038] When the number of shutdown units is two, the total water supply required by the boilers 200 in the system and the circulating air volume of each CDQ furnace 100 are calculated, and the circulating air volume and total water supply of the three CDQ furnaces are adjusted according to the calculated values. At the same time, the CDQ furnaces 100 are interlocked to stop coke discharge and the inert gas charging valve 600 is interlocked to open to inject inert gas into the CDQ furnaces 100 to dilute the combustible gas concentration and ensure safe operation in the CDQ furnaces 100. This can maintain low-load operation of the three boilers 200 for a short period of time.

[0039] The inert gas is nitrogen, the inert gas pressure requirement is ≥0.4~0.7MPa, and the injection time is 10 minutes each time.

[0040] The combustible gases are carbon monoxide CO, carbon dioxide CO2, oxygen O2 and hydrogen H2. The control concentration range is carbon monoxide <6%, carbon dioxide <6%~15%, oxygen <1%, hydrogen <3%, and nitrogen is controlled at 72%~83%.

[0041] The total water supply required by the boiler 200 and the circulating air volume of each CDQ furnace 100 in the system are calculated using program blocks written based on the PLC control system. The calculation parameters involved include main steam flow, main steam pressure, drum liquid level, boiler 200 feed water flow, drum pressure, boiler 200 inlet temperature, boiler 200 feed water pump 301 shutdown signal, circulating air volume, circulating air duct gas composition, and CDQ furnace 100 material level.

[0042] Specifically, in this embodiment, the CDQ mother-tube boiler system includes three CDQ furnaces 100, each connected to a boiler 200 via a circulating gas duct. Circulating gas enters the bottom of the CDQ furnaces 100, exits from the top of the CDQ furnaces 100, enters the boiler 200, and then exits from the bottom of the boiler 200 before reentering the bottom of the CDQ furnaces 100. Because the three CDQ furnaces have independent control systems, the third CDQ control system is selected as the master system.

[0043] Data is transmitted to each other through industrial Ethernet TPC communication and hard-wired connection collection methods. All relevant data and parameters are uniformly entered into the main system. Data collection and processing program modules, shutdown detection program modules, trigger intelligent calculation program modules and control command program modules are developed and established in the main control system. The data collection and processing program module collects the operating data and parameters required for the three CDQ units into the main control system for unified processing. The shutdown detection program module imports operating signals, current values, and other parameters from important equipment such as the boiler 200 feedwater pump 301 and the circulating fan 400, performs control logic judgment through filtering and multiple-choice, and outputs command signals to the triggering intelligent calculation program module. The triggering intelligent automatic calculation program module uses the command signal transmitted by the shutdown automatic detection program module to trigger the logic control and formula calculation designed within the program module, quickly calculate the required total water supply and circulating air volume for each CDQ unit 100, and generate command signals for transmission to the control command program module. The control command program module issues control command signals, including the command signal to open the inert gas charging valve 600, the command signal to stop the coke discharge module 500, and the command signal for the boiler 200 feedwater regulating valve 303. The command signals are transmitted to the program command interfaces of each control system. Each system controls the corresponding equipment to perform the action commands according to the issued commands.

[0044] When the feed water pump 301 of a boiler 200 fails and stops, the intelligent automatic calculation module is triggered to quickly calculate the total water supply required by the three boilers 200 and the circulating air volume of each CDQ furnace 100. The total water supply of the feed water pumps 301 of the two boilers 200 is 130t / h. According to the calculated values, the results are automatically output and the rotation speed of the three CDQ circulating fans 400 is automatically interlocked to be reduced from 1000-1500r / min to 500r / min, and the circulating air volume is reduced from 130000-200000m3 / h to 70000m3 / h. At the same time, the coke discharge operation of the vibrating feeders of the three CDQ furnaces 100 is interlocked to be stopped and the nitrogen valve of the circulating fan 400 is interlocked to open to inject nitrogen into the CDQ furnace 100 to dilute the oxygen and hydrogen concentrations in the CDQ furnace 100. The evaporation capacity of the three 200-ton boilers is about 140t / h, and the total water supply is slightly less than the total evaporation capacity, which is 138t / h. Through adjustment, the drum liquid level of the three boilers 200 can be maintained at low load operation within 25 minutes, which can ensure that the three dry quenching coke can be normally loaded with red coke production without being affected. The three boilers 200 can buy enough time to quickly resume production.

[0045] The operator behind the machine can manually and quickly start the standby boiler 200 water supply pump 301. After the water supply flow is normal, the operator can manually and remotely adjust the circulating air volume and close the nitrogen valve in the central control room. After that, the chip removal device can be manually started remotely and adjusted to relevant parameters suitable for the current working conditions. After 20 minutes of operation, the normal operation of production can be completed.

[0046] Taking three domestically produced 1.5 million tons / year CDQ coke plants as an example, the following table shows the comparison results between the examples and the comparative examples.

[0047]

[0048] As can be seen, when feedwater pump 301 stops, the time it takes for the boiler 200 drum to dry out is reduced, allowing time to implement emergency measures. Within 15 minutes of the feedwater pump 301 stopping, the on-site manual valve can be quickly adjusted and switched, and production can be restored as quickly as possible. Each pump outage reduces downtime by 30 minutes. Boiler 200 does not experience a dry-out process accident, effectively protecting the water-cooled walls and evaporator tubes within the boiler 200 from deformation and cracking caused by short-term hot and cold cycles and thermal expansion and contraction. The implementation of automatic frequency reduction for circulating fan 400 significantly improves operator efficiency and emergency response capabilities, effectively preventing accidents such as dry-out and explosions in the boiler 200. Optimizing industrial control systems through programming or software based on actual usage to enhance the automation and intelligence of equipment is a current industrial trend and holds considerable potential for widespread adoption.

[0049] The present invention also proposes a CDQ mother tube boiler system, which is controlled by the above-mentioned CDQ mother tube boiler low-load operation automatic control method; comprising a CDQ furnace 100; in this embodiment, the number of the CDQ furnaces 100 is three.

[0050] The CDQ mother tube boiler system includes a boiler 200 connected to the CDQ furnace 100. In this embodiment, there are three boilers 200, and the three boilers 200 are connected to the three CDQ furnaces 100 one by one.

[0051] The CDQ mother tube boiler system includes a water supply module 300 for supplying water to the boiler 200. The water supply module 300 includes a water supply pump 301, a water supply mother pipe 302 connected to the water supply pump 301, and a regulating valve 303 arranged between the water supply mother pipe 302 and the boiler 200. Specifically, the water supply mother pipe is the outlet of four water supply pumps 301, which is connected to the water supply mother pipe through four branch water supply pipes to centrally supply water to three boilers 200. Three water supply branch pipes are drawn out from the water supply mother pipe and connected to the three boilers 200 respectively. The water supply branch pipe is installed with a boiler 200 steam drum regulating valve 303 for adjusting the steam drum liquid level.

[0052] The CDQ mother tube boiler system includes a circulating fan 400, which is arranged between the CDQ furnace 100 and the boiler 200. The CDQ furnace 100 is provided with a circulating gas air duct, in which the circulating fan 400 is installed. The inlet and outlet of the circulating fan 400 are respectively provided with inert gas charging valves 600. A coke discharge module 500 is installed at the bottom of the CDQ furnace 100, and a circulating gas composition analyzer is installed at the inlet of the circulating fan 400. The circulating fan 400 uses a high-voltage inverter to adjust the air volume in the circulating air duct. Each circulating fan 400 is equipped with one active and one standby high-voltage inverter.

[0053] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. A method for automatically controlling low-load operation of a dry coke quenching mother tube boiler, characterized by: Used to control the CDQ mother tube boiler system; include, Monitoring the status of a water supply pump (301) in the system to obtain monitoring information; Determining the number of water supply pump (301) shutdowns based on monitoring information; The dry coke quenching mother tube boiler system is regulated according to the number of shutdowns of the feed water pump (301).

2. The automatic control method for low-load operation of a CDQ mother tube boiler according to claim 1, characterized in that: When the number of shutdown units is one, the total water supply and circulating air volume required by the boiler (200) in the system are calculated, and the circulating air volume and total water supply of the dry quenching furnace (100) are adjusted and reduced according to the calculated values, and the coke discharge operation of the dry quenching furnace (100) is stopped by interlock.

3. The automatic control method for low-load operation of a CDQ mother tube boiler according to claim 1, characterized in that: When the number of shutdown units is two, the total water supply required by the boilers (200) in the system and the circulating air volume of each dry quenching furnace (100) are calculated, and the circulating air volume and the total water supply of the dry quenching furnace (100) are adjusted according to the calculated values. At the same time, the dry quenching furnace (100) is interlocked to stop coke discharge and the inert gas charging valve (600) is interlocked to open to inject inert gas into the dry quenching furnace (100) to dilute the concentration of combustible gas.

4. The automatic control method for low-load operation of a CDQ mother tube boiler according to claim 3, characterized in that: The inert gas is nitrogen, the inert gas pressure requirement is ≥0.4-0.7 MPa, and the injection time is 10 minutes each time.

5. The automatic control method for low-load operation of a CDQ mother tube boiler according to claim 4, characterized in that: The combustible gases are carbon monoxide CO, carbon dioxide CO2, oxygen O2 and hydrogen H2. The concentration range of carbon monoxide is controlled to be less than 6%, carbon dioxide is less than 6% to 15%, oxygen is less than 1%, hydrogen is less than 3%, and nitrogen is controlled at 72% to 83%.

6. The automatic control method for low-load operation of a CDQ mother tube boiler according to claim 2 or 3, characterized in that: When calculating the total water supply required by the boiler (200) and the circulating air volume of each dry quenching furnace (100) in the system, a program block written based on a PLC control system is used, and the calculation parameters involved include main steam flow, main steam pressure, drum liquid level, boiler (200) feed water flow, drum pressure, boiler (200) inlet temperature, boiler (200) feed water pump (301) shutdown signal, circulating air volume, circulating air duct gas composition, and dry quenching furnace (100) material level.

7. A dry quenching mother tube boiler system, characterized by: The automatic control method for low-load operation of a dry coke quenching mother tube boiler according to any one of claims 1 to 6 is used for control; include, CDQ furnace (100); A boiler (200) is connected to the dry quenching furnace (100); A water supply module (300) for supplying water to the boiler (200); A circulating fan (400) is provided between the dry quenching furnace (100) and the boiler (200).

8. The CDQ mother tube boiler system according to claim 7, characterized in that: Each of the dry quenching furnaces (100) is equipped with a coke removal module (500).

9. The CDQ mother tube boiler system according to claim 7, characterized in that: The water supply module (300) includes a water supply pump (301), a water supply main pipe (302) connected to the water supply pump (301), and a regulating valve (303) provided between the water supply main pipe (302) and the boiler (200).

10. The CDQ mother tube boiler system according to claim 7, characterized in that: An inert gas charging valve (600) is also provided between the dry quenching furnace (100) and the boiler (200).

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