阅读说明：本技术 一种等离子点火煤粉燃烧器运行控制系统及方法 (Operation control system and method for plasma ignition pulverized coal burner ) 是由 张良平 张宇博 刘超 沈植 杨辉 党黎军 张海龙 付龙龙 陆军 于 2021-08-06 设计创作，主要内容包括：一种等离子点火煤粉燃烧器运行控制系统及方法,包括与DCS控制系统相连的等离子点火控制系统、制粉系统的调节系统和燃烧器监测系统；其中,等离子点火控制系统包括与DCS控制系统相连的冷却水控制模块、载体风控制模块和拉弧电流控制模块；制粉系统的调节系统包括与DCS控制系统相连的磨出口温度控制模块、磨出口一次风速控制模块、给煤量控制模块以及旋转分离器转速控制模块；燃烧器监测系统包括与DCS控制系统相连的火检系统和壁温测量装置。本发明能广泛适用于燃煤发电厂等离子点火煤粉燃烧器的点火控制；各控制模块可充分利用现有的设备装置,投资成本较小,容易实现,具有很好的市场推广价值。(A plasma ignition pulverized coal burner operation control system and method, including plasma ignition control system, regulating system and burner monitoring system of the pulverizing system that link with DCS control system; the plasma ignition control system comprises a cooling water control module, a carrier air control module and an arc discharge current control module which are connected with the DCS control system; the adjusting system of the coal pulverizing system comprises a grinding outlet temperature control module, a grinding outlet primary air speed control module, a coal feeding amount control module and a rotating speed control module of a rotating separator, which are connected with the DCS control system; the combustor monitoring system comprises a fire detection system and a wall temperature measuring device which are connected with the DCS control system. The invention can be widely applied to the ignition control of the plasma ignition pulverized coal burner of the coal-fired power plant; each control module can make full use of the existing equipment, has low investment cost and good market popularization value, and is easy to realize.)

1. A plasma ignition pulverized coal burner operation control system is characterized by comprising a plasma ignition control system, a coal pulverizing system adjusting system and a burner monitoring system, wherein the plasma ignition control system is connected with a DCS control system;

the plasma ignition control system comprises a cooling water control module, a carrier air control module and an arc discharge current control module which are connected with the DCS control system;

the adjusting system of the coal pulverizing system comprises a grinding outlet temperature control module, a grinding outlet primary air speed control module, a coal feeding amount control module and a rotating speed control module of a rotating separator, which are connected with the DCS control system;

the combustor monitoring system comprises a fire detection system and a wall temperature measuring device which are connected with the DCS control system.

2. The system of claim 1, wherein the pulverizing system is a positive pressure direct-fired pulverizing system.

3. A method for controlling the operation of a plasma ignition pulverized coal burner based on the apparatus of claim 1, comprising the steps of:

s1: setting parameters of a cooling water control module, a carrier air control module, an arc discharge current control module, a mill outlet temperature control module, a mill outlet primary air speed control module, a coal feeding amount control module and a rotary separator rotating speed control module according to the quality of coal entering a furnace;

s2: starting a coal mill, and starting ignition of a plasma burner; the operation is carried out according to the parameters in the step S1 through a mill outlet temperature control module, a mill outlet primary air speed control module, a coal supply amount control module and a rotating speed control module of the rotating separator; a fire detection system of the burner monitoring system monitors a fire detection signal in real time, a wall temperature measuring system monitors the wall temperature of the burner in real time, and the monitored fire detection signal and the wall temperature data of the burner are sent to a DCS (distributed control system); the DCS sends the parameter control strategy to the plasma ignition control system and the adjusting system of the powder making system according to the intensity of the fire detection signal and the wall temperature of the combustor; and the adjusting systems of the plasma ignition control system and the pulverizing system timely adjust the parameters of the mill outlet temperature control module, the mill outlet primary air speed control module, the coal supply amount control module and the rotating speed control module of the rotary separator according to the parameter control strategy.

4. The operation control method of plasma ignition pulverized coal burner as claimed in claim 3, characterized in that the parameter control strategy comprises the steps of:

s311: when the fire detection signal is absent or the intensity is lower than 50%, the grinding outlet temperature control module increases the grinding outlet temperature by 1 ℃ every time;

s312: when the primary air heater reaches the maximum output and the temperature of the grinding outlet reaches the maximum value, if the fire detection signal is still absent or the intensity is lower than 50%, the primary air speed of the grinding outlet is reduced by the primary air speed control module of the grinding outlet, the coal feeding amount is increased by the coal feeding amount control module, and the concentration of pulverized coal is increased; wherein, the primary wind speed is reduced by 1m/s each time, so that the primary wind speed of the pulverized coal pipes at the outlets of the coal mills is not lower than 18 m/s; the coal feeding amount is increased by 2t/h every time, and the coal feeding amount is less than the coal feeding amount causing coal blockage of the coal mill at most;

s313: if the fire detection signal is still absent or the intensity is lower than 50%, the rotating speed control module of the rotary separator increases the rotating speed of the rotary separator by 5r/min each time until the fire detection signal is normal;

s314: if the fire detection signal is absent or the intensity is lower than 50%, the arc discharge current of the plasma generator is increased by the arc discharge current control module at the amplitude of 5A each time until the fire detection signal is normal;

s315: and stopping powder feeding if the powder feeding time exceeds 180s and no fire detection signal is detected.

5. The operation control method of plasma ignition pulverized coal burner as claimed in claim 3, characterized in that the parameter control strategy comprises the steps of:

s321: when the wall temperature of the combustor exceeds an alarm value, firstly, the primary wind speed is increased by a primary wind speed control module at the outlet, and the primary wind speed is increased by 1m/s each time;

s322: if the wall temperature of the combustor exceeds the alarm value, the grinding outlet temperature is reduced by the grinding outlet temperature control module in the range of 1 ℃ each time, and is not lower than 60 ℃ or affects the ignition of the combustor.

6. The operation control method of plasma ignition pulverized coal burner as claimed in claim 3, wherein in step S1, the specific process of setting the parameters of the cooling water control module, the carrier air control module, the arc discharge current control module, the mill outlet temperature control module, the mill outlet primary air speed control module, the coal supply amount control module and the rotating speed control module of the rotating separator according to the quality of the coal to be fired is:

setting the temperature of a mill outlet to be not lower than 60 ℃ through a mill outlet temperature control module according to the quality of coal entering the furnace;

setting primary air speed at a grinding outlet to be 18-23 m/s through a primary air speed control module at the grinding outlet according to the quality of coal entering the furnace;

setting the rotating speed of the rotary separator to be 60-120 r/min through a rotating speed control module of the rotary separator according to the coal quality entering the furnace;

setting coal feeding quantity through a coal feeding quantity control module according to the quality of coal entering a furnace;

setting plasma current to be 220-340A through an arc discharge current control module according to the coal quality in the furnace;

the parameters of the cooling water system are set through a cooling water control module according to the coal quality entering the furnace: the cooling water inlet pressure of the cooling water system is 0.4-0.8 MPa, the water temperature is less than 40 ℃, the cooling water pressure difference of an inlet and an outlet of the cooling water system is not less than 0.2MPa, and the cooling water quantity is initially set to be 4-8 t/h;

the parameters of the carrier air system are set through the carrier air control module according to the coal quality entering the furnace: the carrier air pressure is 5-7 kPa, and the flow rate is 1.5Nm³/min。

7. The operation control method of the plasma ignition pulverized coal burner as claimed in claim 3, wherein the coal feeding amount is calculated according to the pulverized coal concentration and the primary air volume, wherein the pulverized coal concentration is 0.3-0.52 kg of pulverized coal/kg of air.

8. The operation control method of plasma ignition pulverized coal burner as claimed in claim 3, wherein the alarm value is 550 ℃.

Technical Field

The invention belongs to the technical field of control of pulverized coal burners, and particularly relates to a system and a method for controlling operation of a pulverized coal burner ignited by plasma.

Background

The plasma ignition technology is widely applied to the ignition technology of coal-fired boiler pulverized coal burners in recent years. The method is characterized in that plasma airflow with higher temperature is formed by a plasma generator, and then the pulverized coal is ignited by the high-temperature plasma airflow. Because the plasma ignition process does not need fuel oil and the ignition speed is high, the consumption of factory fuel oil can be greatly reduced and the operation flexibility of the boiler can be increased. However, due to unreasonable parameter setting or improper operation of some power plant operators, failure of plasma ignition often occurs, and the boiler starting schedule is seriously affected. However, there is still no mature operation control system and method for plasma ignition pulverized coal burner in China, so there is a need to provide an operation control system and method for plasma ignition pulverized coal burner

Disclosure of Invention

The invention aims to provide a plasma ignition pulverized coal burner operation control system and method to ensure smooth ignition and normal operation of a plasma burner during startup ignition and normal operation of a boiler.

In order to achieve the purpose, the invention adopts the following technical scheme:

a plasma ignition pulverized coal burner operation control system comprises a plasma ignition control system, a pulverized coal system adjusting system and a burner monitoring system, wherein the plasma ignition control system, the pulverized coal system adjusting system and the burner monitoring system are connected with a DCS (distributed control system);

the plasma ignition control system comprises a cooling water control module, a carrier air control module and an arc discharge current control module which are connected with the DCS control system;

the adjusting system of the coal pulverizing system comprises a grinding outlet temperature control module, a grinding outlet primary air speed control module, a coal feeding amount control module and a rotating speed control module of a rotating separator, which are connected with the DCS control system;

the combustor monitoring system comprises a fire detection system and a wall temperature measuring device which are connected with the DCS control system.

The invention is further improved in that the pulverizing system is a positive pressure direct-fired pulverizing system.

An operation control method of a plasma ignition pulverized coal burner based on the device comprises the following steps:

s1: setting parameters of a cooling water control module, a carrier air control module, an arc discharge current control module, a mill outlet temperature control module, a mill outlet primary air speed control module, a coal feeding amount control module and a rotary separator rotating speed control module according to the quality of coal entering a furnace;

s2: starting a coal mill, and starting ignition of a plasma burner; the operation is carried out according to the parameters in the step S1 through a mill outlet temperature control module, a mill outlet primary air speed control module, a coal supply amount control module and a rotating speed control module of the rotating separator; a fire detection system of the burner monitoring system monitors a fire detection signal in real time, a wall temperature measuring device monitors the wall temperature of the burner in real time, and the monitored fire detection signal and the wall temperature data of the burner are sent to a DCS (distributed control system); the DCS sends the parameter control strategy to the plasma ignition control system and the adjusting system of the powder making system according to the intensity of the fire detection signal and the wall temperature of the combustor; and the adjusting systems of the plasma ignition control system and the pulverizing system timely adjust the parameters of the mill outlet temperature control module, the mill outlet primary air speed control module, the coal supply amount control module and the rotating speed control module of the rotary separator according to the parameter control strategy.

A further development of the invention is that the parameter control strategy comprises the following steps:

s311: when the fire detection signal is absent or the intensity is lower than 50%, the grinding outlet temperature control module increases the grinding outlet temperature by 1 ℃ every time;

s312: when the primary air heater reaches the maximum output and the temperature of the grinding outlet reaches the maximum value, if the fire detection signal is still absent or the intensity is lower than 50%, the primary air speed of the grinding outlet is reduced by the primary air speed control module of the grinding outlet, the coal feeding amount is increased by the coal feeding amount control module, and the concentration of pulverized coal is increased; wherein, the primary wind speed is reduced by 1m/s each time, so that the primary wind speed of the pulverized coal pipes at the outlets of the coal mills is not lower than 18 m/s; the coal feeding amount is increased by 2t/h every time, and the coal feeding amount is less than the coal feeding amount causing coal blockage of the coal mill at most;

s313: if the fire detection signal is still absent or the intensity is lower than 50%, the rotating speed control module of the rotary separator increases the rotating speed of the rotary separator by 5r/min each time until the fire detection signal is normal;

s314: if the fire detection signal is absent or the intensity is lower than 50%, the arc discharge current of the plasma generator is increased by the arc discharge current control module at the amplitude of 5A each time until the fire detection signal is normal;

s315: and stopping powder feeding if the powder feeding time exceeds 180s and no fire detection signal is detected.

A further development of the invention is that the parameter control strategy comprises the following steps:

s321: when the wall temperature of the combustor exceeds an alarm value, firstly, the primary wind speed is increased by a primary wind speed control module at the outlet, and the primary wind speed is increased by 1m/s each time;

s322: if the wall temperature of the combustor exceeds the alarm value, the grinding outlet temperature is reduced by the grinding outlet temperature control module in the range of 1 ℃ each time, and is not lower than 60 ℃ or affects the ignition of the combustor.

A further improvement of the present invention is that, in step S1,

the concrete process of setting the parameters of the cooling water control module, the carrier air control module, the arc discharge current control module, the mill outlet temperature control module, the mill outlet primary air speed control module, the coal feeding amount control module and the rotating speed control module of the rotating separator according to the coal quality entering the furnace is as follows:

setting the temperature of a mill outlet to be not lower than 60 ℃ through a mill outlet temperature control module according to the quality of coal entering the furnace;

setting primary air speed at a grinding outlet to be 18-23 m/s through a primary air speed control module at the grinding outlet according to the quality of coal entering the furnace;

setting the rotating speed of the rotary separator to be 60-120 r/min through a rotating speed control module of the rotary separator according to the coal quality entering the furnace;

setting coal feeding quantity through a coal feeding quantity control module according to the quality of coal entering a furnace;

setting plasma current to be 220-340A through an arc discharge current control module according to the coal quality in the furnace;

the parameters of the cooling water system are set through a cooling water control module according to the coal quality entering the furnace: the cooling water inlet pressure of the cooling water system is 0.4-0.8 MPa, the water temperature is less than 40 ℃, the cooling water pressure difference of an inlet and an outlet of the cooling water system is not less than 0.2MPa, and the cooling water quantity is initially set to be 4-8 t/h;

the parameters of the carrier air system are set through the carrier air control module according to the coal quality entering the furnace: the carrier air pressure is 5-7 kPa, and the flow rate is 1.5Nm³/min。

The invention has the further improvement that the coal feeding amount is calculated according to the coal powder concentration and the primary air volume, wherein the coal powder concentration is 0.3-0.52 kg of coal powder/kg of air.

A further development of the invention is that the alarm value is 550 ℃.

When the fire detection signal is absent or the intensity is lower than 50%, the temperature of the grinding outlet is increased by a small margin, the primary wind speed of the grinding outlet is reduced, the coal feeding amount is increased, the rotating speed of the rotary separator is increased, and the current of the plasma generator is increased within the allowable range of S2 in sequence until the fire detection signal is normal; stopping powder feeding when the powder feeding time (the starting operation time of each module, namely the powder feeding starting time) exceeds 180s and no fire detection signal is detected;

when the wall temperature of the combustor exceeds the alarm value, the primary air speed of the grinding outlet is properly increased within the allowable range of S2 in sequence, and the temperature of the grinding outlet is properly reduced.

Compared with the prior art, the invention has the following beneficial effects:

when the operation control system and the operation control method of the plasma ignition pulverized coal burner are operated specifically, a fire detection system and a wall temperature measuring device of a burner monitoring system can monitor a fire detection signal and the wall temperature of the burner in real time, and the result is fed back to a plasma ignition control system and an adjusting system of a pulverizing system through a DCS (distributed control system); the plasma ignition control system and the adjusting system of the powder making system can adjust parameters of each control module in time according to the intensity of the fire detection signal and the wall temperature of the burner in real time, and ensure stable ignition and operation of the plasma ignition pulverized coal burner; the invention can be widely applied to the ignition control of the plasma ignition pulverized coal burner of the coal-fired power plant; each control module can make full use of the existing equipment, has low investment cost and good market popularization value, and is easy to realize.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention.

In the figure, 1 is a fire detection system, 2 is a wall temperature measuring device, 3 is a grinding outlet temperature control module, 4 is a grinding outlet primary air speed control module, 5 is a coal supply control module, 6 is a rotating speed control module of a rotary separator, 7 is a cooling water control module, 8 is a carrier air control module, and 9 is an arc discharge current control module.

Detailed Description

The following embodiments of the present invention are provided, and it should be noted that the present invention is not limited to the following embodiments, and all equivalent changes based on the technical solutions of the present invention are within the protection scope of the present invention.

Following the above technical solution, as shown in fig. 1, the present embodiment provides a system and a method for controlling operation of a plasma ignition pulverized coal burner to ensure smooth ignition and normal operation of the plasma burner during startup ignition and normal operation of a boiler.

Example 1

Referring to fig. 1, an operation control system of a plasma ignition pulverized coal burner includes a plasma ignition control system connected to a DCS control system, a regulation system of a pulverizing system, and a burner monitoring system.

The plasma ignition control system comprises a cooling water control module 7, a carrier air control module 8 and an arc discharge current control module 9 which are connected with the DCS control system.

The powder-making system is a positive pressure direct-fired powder-making system (a rotary separator is arranged at the outlet of a coal mill), the powder-making system comprises an adjusting system, and the powder-making system is well known in the field. The adjusting system of the pulverizing system comprises a grinding outlet temperature control module 3, a grinding outlet primary air speed control module 4, a coal feeding amount control module 5 and a rotating speed control module 6 which are connected with a DCS control system.

The combustor monitoring system comprises a fire detection system 1 and a wall temperature measuring device 2, and the fire detection system 1 and the wall temperature measuring device 2 are both connected with a DCS control system.

An operation control method of a plasma ignition pulverized coal burner based on the system comprises the following steps:

s1: a plasma ignition preparation phase. Before plasma ignition, procedures such as air feeding, induced draft fan, furnace chamber purging and the like are completed according to operation rules, and the parameters of each subsystem of the plasma ignition system are comprehensively checked to be normal.

S2: and determining initial values of the system parameters. The data of the coal quality of the coal as fired is input into a plasma ignition control system and an adjusting system of a pulverizing system, and the coal quality of the coal as fired used in the embodiment 1 comprises the following main components: the basic ash A is collected_ar20% of water, M_ar10% dry ash-free base volatile component V_daf40%. And setting initial values of modules of the plasma ignition control system, the adjusting system of the coal pulverizing system and the burner monitoring system according to the quality of coal entering the furnace.

The parameters of each control module during the ignition and operation of the combustor are as follows:

grind export temperature through grinding export temperature control module 3 setting: controlling according to the coal quality volatile component, wherein the temperature is not lower than 60 ℃, and the lower the coal quality volatile component content is, the higher the temperature control of the initial mill outlet is;

according to the main components of the coal quality of the furnace coal, the initial value of the mill outlet temperature is set to 63 ℃ during ignition in the embodiment. After normal operation, the temperature of the outlet of the mill is not lower than 60 ℃.

Setting the primary air speed of the mill outlet to be 18-23 m/s through the primary air speed control module 4 of the mill outlet, wherein the primary air speed control of the mill outlet is lower as the content of volatile components in coal is lower;

in the embodiment, the initial value of the primary wind speed of the outlet is set to be 21m/s during ignition, and the primary wind speed of the outlet is 18-23 m/s after normal operation.

The rotating speed of the rotary separator is set to be 60-120 r/min through the rotating speed control module 6 of the rotary separator, the rotating speed of the initial grinding rotary separator is set to be higher as the content of volatile components in coal is lower, but the maximum rotating speed cannot cause the abnormal phenomenon of grinding blockage of the coal mill.

In the implementation, the initial value of the rotating speed of the rotating separator is set to be 90r/min during ignition, and after normal operation, the rotating speed of the rotating separator is 60-120 r/min.

The coal feeding amount is set through the coal feeding amount control module 5: the coal feeding amount is calculated according to the primary air volume, the lower the content of coal volatile components is, the higher the control of the coal powder concentration at the initial grinding outlet is, and the larger the coal feeding amount is; the maximum value should not cause the coal mill to generate abnormal phenomena of blocking or pebble coal, and the minimum value should not cause the coal mill to generate abnormal vibration.

In the embodiment, the coal powder concentration is ensured to be 0.4kg of coal powder/kg of air during ignition, and the coal feeding amount during ignition is 36t/h (the coal feeding amount for coal paving is increased by 5t/h each time and gradually increased to the value, and the coal feeding amount is increased temporarily if the coal blockage phenomenon occurs in the increasing process) calculated according to the primary air volume.

The plasma current is set to be 220-340A through the arc discharge current control module 9, and the lower the content of the volatile components in the coal is, the higher the initial plasma current is set.

In the embodiment, the initial value of the plasma current is set to 300A during ignition, and the plasma current is 220-340A after normal operation.

A cooling water system is set through the cooling water control module 7: when the plasma igniter is operated, the cooling water inlet pressure of the plasma igniter is 0.4-0.8 MPa (in the embodiment, during ignition, the initial value of the cooling water inlet pressure of the plasma igniter is set to be 0.6MPa), the water temperature is less than 40 ℃, the pressure difference of inlet and outlet cooling water is not less than 0.2MPa, and the initial value of the cooling water amount is set to be 4-8 t/h, preferably 6 t/h.

Control module by carrier wind8, setting carrier air system parameters: the carrier air pressure is 5-7 kPa, and the flow rate is 1.5Nm³/min。

S3: after warm grinding and coal paving are completed, starting a coal mill, and starting ignition of a plasma burner; at the moment, the coal mill runs according to the initial set value in the step S2 through all modules (namely a mill outlet temperature control module 3, a mill outlet primary air speed control module 4, a coal feeding amount control module 5 and a rotary separator rotating speed control module 6) of an adjusting system of the coal pulverizing system; a fire detection system 1 of the burner monitoring system monitors fire detection signals in real time, a wall temperature measuring device 2 monitors wall temperature of the burner in real time, and the monitored fire detection signals and wall temperature data of the burner are sent to a DCS (distributed control system); the DCS sends a new parameter control strategy to the plasma ignition control system and the adjusting system of the powder making system according to the intensity of the fire detection signal and the wall temperature of the combustor; and adjusting the parameters of each control module in time by the adjusting systems of the plasma ignition control system and the powder making system according to a new parameter control strategy.

The new parameter control strategy is specifically as follows:

s311: when the fire detection signal is absent or the intensity is lower than 50%, the grinding outlet temperature control module 3 increases the grinding outlet temperature by 1 ℃ every time;

s312: when the primary air heater reaches the maximum output, the output cannot be further improved, and the temperature of the grinding outlet is improved to the maximum value, if the fire detection signal is still absent or the intensity is lower than 50%, the primary air speed of the grinding outlet is reduced through the primary air speed control module 4 of the grinding outlet in sequence, and then the coal feeding amount is improved through the coal feeding amount control module 5, so that the concentration of the pulverized coal is improved; wherein, the primary wind speed is reduced by 1m/s each time (generally, the primary wind quantity at the inlet of the coal mill is reduced), but the primary wind speed of a powder pipe at the outlet of each coal mill is not lower than 18 m/s; the coal feeding amount is increased by 2t/h every time, but the abnormal phenomena of coal blockage or pebble coal of a coal mill cannot be caused at the highest;

s313: after primary wind speed and coal feeding amount are adjusted, if the fire detection signal is still absent or the intensity is lower than 50%, the rotating speed of the rotary separator is gradually increased by the rotating speed control module 6 at the amplitude of 5r/min each time until the fire detection signal is normal; if the coal blockage phenomenon occurs after the rotating speed is increased, the rotating speed is restored to the level before the rotating speed is increased;

s314: after the rotating speed of the rotary separator is adjusted, if the fire detection signal is still absent or the intensity is lower than 50%, the arc discharge current of the plasma generator is increased by the amplitude of 5A at each time through the arc discharge current control module 9 until the fire detection signal is normal; the current of the plasma generator cannot exceed a rated value, and the current is properly reduced after the ignition is successful and the boiler stably operates, so that the service lives of a cathode head and an anode head of the plasma generator are prolonged;

s315: after the measures are adopted, if the powder feeding time exceeds 180s and no fire detection signal is detected, stopping powder feeding, comprehensively checking the conditions of each device of the plasma ignition system and the powder preparation system, and processing corresponding defects.

Or the new parameter control strategy specifically comprises:

s321: when the wall temperature of the combustor exceeds an alarm value (such as 550 ℃), firstly, properly increasing the primary air speed through an outlet grinding primary air speed control module 4, wherein the primary air speed is increased by 1m/s each time (generally, the primary air quantity of an inlet of a coal grinding mill is increased) until the wall temperature of the combustor is lower than the alarm value, but the ignition of the combustor is not influenced after the primary air speed is increased, otherwise, the wall temperature is restored to the level before the increase;

s322: after the primary air speed is adjusted, if the wall temperature of the combustor still exceeds the alarm value, the grinding outlet temperature is reduced by 1 ℃ every time through the grinding outlet temperature control module 3, but the grinding outlet temperature is not lower than 60 ℃ or the combustion of the combustor is influenced.