CN106949739A - Fluidized bed furnace method for security protection and safety guard - Google Patents

Abstract

The invention provides a safety protection method and safety protection device for a fluidized fluidized furnace, wherein the method includes automatically detecting the pressure in the furnace of the combustion chamber and setting the upper limit of the pressure; if the pressure in the furnace of one of the combustion chambers exceeds the upper limit of the set pressure and continues If the alarm duration is within the second preset time period, if the pressure in the combustion chamber is lower than the upper pressure limit, the alarm will be eliminated; if the alarm duration exceeds the second preset time period In the first stage, if the pressure in the furnace of the combustion chamber still exceeds the upper limit of the pressure, the exhaust equipment is controlled to reduce the exhaust air volume until the pressure in the furnace of the combustion chamber is lower than the upper limit of the pressure. The pressure signal inside the furnace is automatically collected and monitored. When the pressure exceeds the upper limit, the operator can be alerted to take measures. When the pressure is still higher than the upper limit within the set time, the pressure in the furnace can be automatically reduced.

Description

Fluidized furnace safety protection method and safety protection device

technical field

The invention relates to a gypsum board production technology, in particular to a safety protection method and a safety protection device for a fluidized fluidized furnace.

Background technique

Fluidized fluidized furnace is the supplier of heat source in the production process of paper surface gypsum board. The main structure of fluidized fluidized furnace is brick structure. There are two furnace combustion chambers in fluidized fluidized furnace. The chamber generates negative pressure in the combustion chamber through the cooperation of the primary fan (air intake function) and the main induced draft fan (air outlet function), and draws heat from the combustion chamber to heat the heat transfer oil. During this process, if the post personnel operate improperly, the negative pressure in the combustion chamber will be too high. The long-term excessive negative pressure in the combustion chamber will cause the deformation of the brick-structured fluidized furnace wall, and in severe cases, it will collapse and cause irreversible damage. The maintenance of the fluidized fluidized furnace is complicated. Once irreversible damage is caused, it will cause shutdown accidents and huge economic losses.

Contents of the invention

The invention provides a fluidized furnace safety protection method and a safety protection device, which are used to overcome the defects in the prior art, control the pressure in the combustion chamber within an appropriate range, avoid excessive negative pressure in the combustion chamber, and reduce the resulting failure of the fluidized furnace. Deformation and downtime accidents, improve the operation rate and safety performance of fluidized fluidized furnace.

The invention provides a fluidized furnace safety protection method, comprising the following steps:

Step 1, automatically detect the pressure in the combustion chamber and set the pressure upper limit;

Step 2, if the pressure in one of the combustion chambers exceeds the set pressure upper limit and continues for the first preset time period, an alarm is issued;

Step 3, the duration of the alarm is within the second preset time period, and the pressure in the furnace of the combustion chamber is lower than the upper pressure limit, then the alarm is eliminated;

If the duration of the alarm exceeds the second preset time period and the pressure in the combustion chamber still exceeds the upper pressure limit, the exhaust equipment is controlled to reduce the exhaust air volume until the pressure in the combustion chamber is lower than the upper pressure limit.

The present invention also provides a fluidized furnace safety protection device, comprising:

The pressure detection element detects the pressure in the combustion chamber and sends a pressure signal;

controller, including:

An alarm unit collects the pressure signal, and compares the value of the pressure signal with the value of the set pressure upper limit, and sends an alarm signal if the former is greater than the latter and lasts for a first preset time period;

The control unit continues to receive the above-mentioned alarm signal for a second preset time period, and sends a control command to the exhaust equipment to reduce the exhaust air volume until the pressure in the combustion chamber is lower than the upper pressure limit;

The alarm device receives the above-mentioned alarm signal and sends out an audible and visual signal.

The fluidized furnace safety protection method and protection device provided by the present invention set the upper limit of the pressure, and detect the internal pressure of the combustion chamber furnace through the pressure detection element. After receiving or seeing the alarm, take measures to reduce the pressure in the furnace. If the operator does not operate within the set time, the controller will automatically control the main induced draft fan, which is the exhaust air volume of the exhaust equipment, to reduce the internal pressure of the furnace. It falls below the upper limit of the set pressure, thereby reducing unnecessary maintenance and shutdown of the fluidized fluidized furnace due to excessive negative pressure inside the furnace.

Description of drawings

Fig. 1 is a structural schematic diagram of a fluidized furnace safety protection device provided by an embodiment of the present invention.

detailed description

Fig. 1 is a schematic structural view of a fluidized furnace safety protection device provided by an embodiment of the present invention; as shown in Fig. The detection element 1 is used to detect the internal pressure of the combustion chamber furnace 10, and send the pressure signal to the controller; the pressure detection unit here can be a pressure transmitter, and the pressure signal here is an analog signal, specifically a 4-20mA current signal Of course, it can also be an analog signal such as a voltage signal; in this embodiment, the fluidized fluidized furnace 100 has two combustion chamber furnaces 10, each of which is provided with a pressure detection element 1;

The controller 2 includes an alarm unit 21 and a control unit 22. After the alarm unit 21 collects the pressure signal from the pressure detection element 1, the pressure signal in the form of an analog signal is converted into a digital signal by an internal analog-to-digital converter to form a measured pressure, and the The measured pressure is compared with the set pressure upper limit (can be set in the alarm unit according to the anti-deformation ability of the fluidized fluidized furnace itself, and the temperature upper limit is -200pa in the present embodiment), if the pressure in the furnace is higher than the upper pressure limit (that is, the temperature in the furnace The measured pressure cannot be higher than -200pa. For example, if the measured pressure is -201pa, it is considered to exceed the upper temperature limit), and lasts for the first preset time period (set according to the specific situation, here is 1 minute), then it will be sent to the alarm 3. Alarm signal; the alarm device 3 receives the above-mentioned alarm signal, and sends an audible and visual signal, prompting the operator to take measures to reduce the internal pressure of the furnace; if the alarm continues to reach the second preset time period (set according to the specific situation, here is 2 minutes) And no one takes measures, then enter the automatic control program, the control unit 22 automatically sends a control command to make the exhaust equipment 20 reduce the exhaust air volume, until the measured pressure in the combustion chamber furnace is lower than the upper pressure limit.

The control unit 22 has a first control unit 22a for controlling the rotational speed of the exhaust setting motor and a second control unit 22b for controlling the opening and closing of the valve arranged at the air inlet or exhaust port of the exhaust fan device 20 (it can also be one of the Any one, in this embodiment, in order to quickly reduce the pressure in the furnace, the first control unit and the second control unit are used to work together). This valve can be an electric valve. The controller in the above embodiments may be a programmable controller (hereinafter referred to as PLC).

The first control unit 22a reduces the exhaust air volume by controlling the speed of the exhaust equipment motor 30; Exhaust air volume; the exhaust air equipment is the main induced draft fan, the rotating speed of the motor of the main induced draft fan is adjusted by the frequency converter, and the frequency converter is connected with the first control unit 22a. The controller sends control instructions, such as reducing the frequency of the frequency converter by 1 Hz, and reducing the speed of the main induced draft fan motor. During this period, the alarm unit 21 still regularly collects pressure signals. The inverter sends a control command, and the frequency of the inverter is reduced by 1Hz again. If the detected pressure is lower than the upper limit of the pressure, the automatic control program will exit. The 1Hz here is the preset amplitude of the adjustment frequency, which can be set to 2Hz or 0.5Hz according to the specific situation.

When the air outlet or air inlet is reduced by the second control unit 22b, the second control unit 22b sends a pulse signal to the electric valve 40 as a control instruction, for example, the valve plate of the electric valve turns 5 degrees in the direction of reducing the valve opening, which During this period, the alarm unit 21 still regularly collects pressure signals. If the detected pressure is still greater than the pressure upper limit, the second control unit 22b sends a control command to the electric valve again, and the valve plate of the electric valve rotates 5 degrees in the same direction again. If the detected pressure is less than Pressure upper limit, exit the automatic control program. The 5 degrees here is the preset amplitude of the adjustment, which can be set to 10 degrees or 2 degrees according to the specific situation. Combined with reducing the speed of the main induced draft fan, the purpose of rapidly reducing the exhaust air volume can be achieved and the pressure in the furnace can be reduced.

The controller 2 also includes a troubleshooting unit 23, and the fluidized furnace safety protection device also includes a display unit 4. After the troubleshooting unit 23 collects and receives the pressure signal sent by the pressure detection unit 1, it can convert the pressure signal in the form of an analog signal through an internal analog-to-digital converter. After the pressure signal is converted into a digital signal, the measured pressure value is formed, and the measured pressure value is compared with the set fault pressure value far greater than the upper pressure limit (in this embodiment, the fault pressure value is -500pa, that is, the measured pressure inside the furnace cannot be higher than -500pa, for example -501pa, it is determined to exceed the fault pressure value) for comparison, if the former is greater than or equal to the latter, then send a troubleshooting signal; the display unit receives the troubleshooting signal and displays the troubleshooting components. Misoperation due to failure of the pressure detection unit itself is prevented.

The above-mentioned pressure detection element 1 adopts a pressure transmitter. In order to reduce signal interference, it can also be installed between the pressure transmitter and the alarm unit 21, between the first control unit 22a and the frequency converter, and between the second control unit 22b and the electric valve 40. An isolator 5 is added between them.

The embodiment of the present invention also provides a fluidized furnace safety protection method, comprising the following steps:

Step 1. Automatically detect the pressure in the combustion chamber through the pressure transmitter, regularly collect the pressure signal from the pressure transmitter through the alarm unit, and set the pressure upper limit in the alarm unit;

Step 2, if the measured pressure in any one of the combustion chamber furnace exceeds the set pressure upper limit and continues for the first preset time period, the alarm unit sends an alarm signal to the alarm to alarm; if the measured pressure in the combustion chamber furnace If the pressure exceeds the upper limit far and reaches the fault pressure value preset in the troubleshooting unit, the above pressure detection signal will be ignored, it will be judged as a pressure detection fault, and the display unit will prompt the operator to check the pressure detection element;

Step 3, if the alarm duration of the alarm is within the second preset time period, and the pressure in the furnace of the combustion chamber is lower than the upper pressure limit, the alarm is eliminated;

If the duration of the alarm exceeds the second preset time period and the pressure in the combustion chamber still exceeds the upper pressure limit, the exhaust equipment is controlled to reduce the exhaust air volume until the pressure in the combustion chamber is lower than the upper pressure limit.

In this embodiment, the fluidized furnace has two combustion chambers. If any one of the measured pressures in the two furnaces exceeds the range of -200pa and lasts for 1 minute, the computer-controlled host computer of the fluidized fluidized furnace will give an alarm, and an alarm screen will pop up, and the main unit will be lowered after 2 minutes. The frequency of the induced draft fan motor is 1Hz. During this period, if the post manually takes measures to control the pressure in the furnace within -200pa, the program will not take measures. If the manual does not participate in the adjustment, the program will automatically reduce the frequency of the main induced draft fan motor by 1Hz after 2 minutes of alarm. If the control range cannot be reached after lowering, repeat the above operations until the required control range is reached. In order to prevent operational risks caused by program misoperation under special circumstances, special circumstances have been added to the program control to ensure normal production.

Special case 1. Pressure furnace: At this time, the program automatically detects that when one of the two combustion chambers of the fluidized fluidized furnace has a coal discharge system that is not in operation, the default is that the post workers have adopted the pressure furnace operation. At this time, as long as the negative pressure of one furnace meets the requirements, the program will no action will be taken;

Special case 2. Pressure transmitter failure: According to production experience, if the furnace negative pressure exceeds -500pa or more, the program will regard it as a failure of the pressure transmitter of the instrument for detecting negative pressure, and the negative pressure data will be regarded as an invalid signal. The boiling furnace computer controls the upper computer to alarm, and the alarm screen pops up, but no control measures are taken.

Claims (8)

1. A fluidized furnace safety protection method, is characterized in that, comprises the following steps: Step 1, automatically detect the pressure in the combustion chamber and set the pressure upper limit; Step 2, if the pressure in one of the combustion chambers exceeds the set pressure upper limit and continues for the first preset time period, an alarm is issued; Step 3, the duration of the alarm is within the second preset time period, and the pressure in the furnace of the combustion chamber is lower than the upper pressure limit, then the alarm is eliminated; If the duration of the alarm exceeds the second preset time period and the pressure in the combustion chamber still exceeds the upper pressure limit, the exhaust equipment is controlled to reduce the exhaust air volume until the pressure in the combustion chamber is lower than the upper pressure limit. 2. The safety protection method for fluidized fluidized furnace according to claim 1, characterized in that, in said step 3, the exhaust air volume is reduced by controlling the rotation speed of the exhaust equipment to decrease. 3. The safety protection method for fluidized fluidized furnace according to claim 1, characterized in that, in said step 3, the exhaust air volume is reduced by controlling the air exhaust port of the exhaust equipment to become smaller. 4. The boiling furnace safety protection method according to claim 1, characterized in that, between step 2 and step 3, the following steps are also included: Step S, if the pressure in the combustion chamber in step 2 far exceeds the upper pressure limit and reaches the fault pressure value, ignore the above pressure detection signal, judge it as a pressure detection fault, and prompt the operator to perform pressure detection Components are checked. 5. A fluidized furnace safety protection device, characterized in that it comprises: The pressure detection element detects the pressure in the combustion chamber and outputs the pressure signal; a controller, further comprising: An alarm unit collects the pressure signal, and compares the value of the pressure signal with the set pressure upper limit, and if the former is greater than the latter and lasts for a first preset time period, then an alarm signal is sent; The control unit continues to receive the above-mentioned alarm signal for a second preset time period, and sends a control command to the exhaust equipment to reduce the exhaust air volume until the pressure in the combustion chamber is lower than the upper pressure limit; The alarm device receives the above-mentioned alarm signal and sends out an audible and visual signal. 6. The safety protection device for fluidized fluidized furnace according to claim 5, characterized in that, the control unit has a first control unit for controlling the rotation speed of the exhaust air setting motor. 7. The safety protection device for fluidized fluidized furnace according to claim 5, wherein the control unit has a second control unit for controlling the opening and closing degree of the valve arranged at the exhaust port of the exhaust fan equipment. 8. The boiling furnace safety protection device according to claim 5, wherein the controller further comprises: The troubleshooting unit collects the pressure signal, and compares the value of the pressure signal with a set fault pressure value far greater than the upper pressure limit, and if the former is greater than or equal to the latter, then sends a troubleshooting signal; The fluidized furnace safety protection device also includes: The display unit receives the troubleshooting signal and displays the troubleshooting components.