Coal-fired power plant boiler furnace pressure protection system
By using pressure transmitters and a 'two-out-of-four' logic judgment method, the instrument status of the boiler furnace pressure protection system is monitored and processed in real time. This solves the problems of pressure switch instrument status not being able to be monitored in real time and the 'two-out-of-three' redundancy configuration in the existing technology, achieving higher safety and reliability and ensuring the stable operation of the boiler system in thermal power plants.
Patent Information
- Application Number
- CN202520204174.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-10
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2035-02-10
AI Technical Summary
In existing technologies, the status of pressure switch instruments in boiler furnace pressure protection systems cannot be monitored in real time, which leads to the failure to detect faults in a timely manner and easily causes protection malfunctions or failures to operate. Furthermore, the "two out of three" redundancy configuration is prone to protection malfunctions and non-shutdowns due to instantaneous pressure fluctuations in individual parts of the furnace.
Pressure transmitters are used instead of pressure switches as sensors. A 'two-out-of-four' logic judgment method is adopted to monitor instrument values in real time and make quality judgments. Pressure protection instruments with the same trend are set separately to avoid protection failure caused by unilateral pressure fluctuations and instrument failures.
It improves the safety and reliability of boiler furnace pressure protection, avoids false tripping or failure to trip, and ensures the safe and stable operation of boiler systems in thermal power plants.
Smart Images
Figure CN223882309U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of thermal power plant, and particularly relates to a coal-fired power plant boiler furnace pressure protection system. BACKGROUND
[0002] Boiler furnace pressure protection is one of the most important protection circuits of thermal power plants. When the unit is normally operated, the coal-fired power plant boiler furnace pressure should be kept in a slightly negative pressure state, so as to ensure efficient combustion of the furnace and normal discharge of flue gas. When the negative pressure is too large due to improper furnace pressure regulation, the furnace will be extinguished, coal powder will accumulate, and in severe cases, an implosion accident may occur; when the negative pressure is too small or even high positive pressure, high-temperature flue gas leakage will occur, and in severe cases, personnel injury and equipment damage accidents may occur. Therefore, the coal-fired boiler furnace protection system generally sets different pressure protection action circuits for pressure high two values, pressure high three values, pressure low two values and pressure low three values.
[0003] In the prior art, the sensor for furnace pressure protection generally adopts a pressure switch instrument. For each protection circuit of furnace pressure high two values, pressure high three values, pressure low two values and pressure low three values, three pressure switches are respectively arranged, and a total of twelve pressure switch instrument signals are sent to the furnace protection system DI channel. A "two out of three" logic judgment mode is adopted. When the logic judgment reaches the limit set value, an action instruction is output to the boiler trip relay cabinet through the furnace protection system DO channel to execute the boiler protection action. Since the pressure switch instrument only acts when the pressure set value is reached, the working state of the pressure switch cannot be effectively and timely monitored, instrument faults cannot be found in time, and protection misoperation or protection refusal caused by detection instruments may endanger the safety of the unit; on the other hand, the "two out of three" redundancy mode of the furnace pressure necessarily requires that one pressure sensor is arranged on one side and two pressure sensors are arranged on the other side of the left and right sides of the furnace. When the pressure of a certain part of the furnace fluctuates instantaneously, protection misoperation may occur, leading to non-stop of the unit, which is not conducive to the reliable operation of the unit. The above problems and hidden dangers have occurred in actual cases of thermal power projects. CONTENT OF THE UTILITY MODEL
[0004] The technical problem to be solved by the utility model is to provide a coal-fired power plant boiler furnace pressure protection system, to solve the problem that the state of the pressure switch instrument in the prior art cannot be monitored in real time, instrument faults cannot be found in time, and protection misoperation or refusal caused by detection instruments may occur, and the problem that the "two out of three" redundancy configuration mode may cause protection misoperation of the unit due to instantaneous pressure fluctuation of individual parts of the furnace, so that the furnace pressure protection has higher safety and reliability, and the safe and stable operation of the boiler system of the thermal power plant is ensured.
[0005] The utility model discloses a kind of coal-fired power plant boiler furnace pressure protection systems, boiler furnace is divided into furnace left side and furnace right side, first pressure transmitter, second pressure transmitter, fifth pressure transmitter and sixth pressure transmitter are connected to the left side of boiler furnace, third pressure transmitter, fourth pressure transmitter, seventh pressure transmitter and eighth pressure transmitter are connected to the right side of boiler furnace, first pressure transmitter, second pressure transmitter, fifth pressure transmitter, sixth pressure transmitter, third pressure transmitter, fourth pressure transmitter, seventh pressure transmitter and eighth pressure transmitter are connected with boiler furnace protection system, and boiler furnace protection system is connected with boiler tripping relay cabinet.
[0006] Further, the first AI card piece, the second AI card piece, the third AI card piece, the fourth AI card piece, the four-to-two logic function block, the first DO card piece, the second DO card piece, the third DO card piece are included in the boiler furnace protection system, the first pressure transmitter and the seventh pressure transmitter are connected with the first AI card piece, the second pressure transmitter and the eighth pressure transmitter are connected with the second AI card piece, the third pressure transmitter and the fifth pressure transmitter are connected with the third AI card piece, the fourth pressure transmitter and the sixth pressure transmitter are connected with the fourth AI card piece, the first AI card piece, the second AI card piece, the third AI card piece and the fourth AI card piece are connected with the four-to-two logic function block, the four-to-two logic function block is connected with the first DO card piece, the second DO card piece and the third DO card piece, and the first DO card piece, the second DO card piece and the third DO card piece are connected with the boiler tripping relay cabinet.
[0007] Further, it includes the first protection circuit for realizing pressure high binary and pressure low binary protection, and the second protection circuit for realizing pressure high ternary and pressure low ternary protection;The first pressure transmitter, the second pressure transmitter, the third pressure transmitter and the fourth pressure transmitter are connected in the first protection circuit;The fifth pressure transmitter, the sixth pressure transmitter, the seventh pressure transmitter and the eighth pressure transmitter are connected in the second protection circuit.
[0008] Compared with the prior art, the utility model has the beneficial technical effects as follows:
[0009] The boiler furnace pressure protection is one of the most important protection circuits in the thermal power plant. The utility model discloses a pressure transmitter (PT) is used to replace the pressure switch as the sensor instrument of furnace pressure protection, can real-time monitoring the value and change trend of instrument, the quality of input signal can be judged to the protection system, when the value of one transmitter is obviously deviated from the value of other transmitters, can be found in time and handle, thereby avoiding the protection malfunction or refusal caused by instrument failure, in addition, through the logic judgment mode of " four take two " instead of " three take two ", each protection circuit furnace left and right sides are provided with 2 transmitters, can avoid the problem that the instantaneous fluctuation of single side pressure of " three take two " mode leads to the protection malfunction of boiler, in addition, the utility model discloses that the pressure protection instrument (high two values and high three values, low two values and low three values) of same trend is set separately, i.e. a group of transmitters realize the " four take two " logic of high two values and low two values, another group of transmitters realize the " four take two " logic of high three values and low three values, avoid the consequence that the ability of furnace pressure grading protection is completely lost when the same trend instrument fails simultaneously because of common reason, make the furnace pressure protection have higher safety and reliability simultaneously, thereby guaranteeing the safe and stable operation of thermal power plant boiler system. BRIEF DESCRIPTION OF DRAWINGS
[0010] Figure 1 It is the schematic diagram of the boiler system arrangement structure provided by the utility model.
[0011] Figure 2 It is the structure block diagram of the boiler furnace pressure protection system provided by the utility model.
[0012] Explanation of reference numerals in the drawings:
[0013] 1, boiler body;2, left side of furnace;3, right side of furnace;4, first pressure transmitter;5, second pressure transmitter;6, fifth pressure transmitter;7, sixth pressure transmitter;8, third pressure transmitter;9, fourth pressure transmitter;10, seventh pressure transmitter;11, eighth pressure transmitter;12, boiler furnace protection system;13, boiler tripping relay cabinet;14, first AI card piece;15, second AI card piece;16, third AI card piece;17, fourth AI card piece;18, four take two logic function block;19, first DO card piece;20, second DO card piece;21, third DO card piece. DETAILED DESCRIPTION
[0014] The utility model provides a kind of coal-fired power plant boiler furnace pressure protection system, using pressure transmitter replaces pressure switch as the sensor instrument of furnace pressure protection, using the logic judgment mode of "four take two" replaces "three take two", solve the state of pressure switch instrument cannot be monitored in real time, cannot be found in time and cause the problem of protection malfunction or refusal due to monitoring instrument reason, and "three take two" redundant configuration mode is prone to cause protection malfunction unit non-stop problem due to the instantaneous pressure fluctuation of individual part of furnace, make furnace pressure protection simultaneously have higher safety and reliability, to ensure that thermal power plant boiler system safe and stable operation.
[0015] Please refer to Figure 1 The utility model discloses a kind of coal-fired power plant boiler furnace pressure protection system, boiler furnace 1 is divided into furnace left side 2 and furnace right side 3, first pressure transmitter 4, second pressure transmitter 5, fifth pressure transmitter 6 and sixth pressure transmitter 7 are connected in furnace left side 2 (for example, left front wall, left rear wall on in boiler furnace) of boiler furnace, third pressure transmitter 8, fourth pressure transmitter 9, seventh pressure transmitter 10 and eighth pressure transmitter 11 are connected in furnace right side 3 (for example, left front wall, left rear wall on in boiler furnace), first pressure transmitter 4, second pressure transmitter 5, fifth pressure transmitter 6, sixth pressure transmitter 7, third pressure transmitter 8, fourth pressure transmitter 9, seventh pressure transmitter 10 and eighth pressure transmitter 11 are connected with boiler furnace protection system (FSS) 12, boiler furnace protection system 12 is connected with boiler trip relay cabinet (MFT) 13.
[0016] Further, the coal-fired power plant boiler furnace pressure protection system of the utility model includes first protection circuit for realizing pressure high binary and pressure low binary protection, and second protection circuit for realizing pressure high ternary and pressure low ternary protection. The definition of pressure high binary, pressure low binary, pressure high ternary, pressure low ternary and the implementation mode of corresponding protection circuit function are all prior art or easy to realize based on prior art, and are not repeated here, the improvement of the present scheme is that the corresponding protection actions of the four pressure values are divided into two groups, and are realized by two protection circuits.
[0017] Each protection circuit has four pressure transmitters, and the four pressure transmitters are connected with the boiler furnace protection system 12.
[0018] Preferably, the first pressure transmitter 4, the second pressure transmitter 5, the third pressure transmitter 8 and the fourth pressure transmitter 9 correspond to each other, for example, correspond to each other in position and close to each other, and are located in the first region as a first group of pressure transmitters; the fifth pressure transmitter 6, the sixth pressure transmitter 7, the seventh pressure transmitter 10 and the eighth pressure transmitter 11 correspond to each other, for example, correspond to each other in position and close to each other, and are located in the second region as a second group of pressure transmitters.
[0019] It can be understood that the four pressure transmitters respectively located on the left and right sides of the boiler furnace in the utility model can also be selected to be set for other pressure values, and the utility model is not limited to the preferred embodiments described in detail.
[0020] More specifically, please refer to Figure 2 The first AI card 14, the second AI card 15, the third AI card 16, the fourth AI card 17, the two-out-of-four logic function block 18, the first DO card 19, the second DO card 20 and the third DO card 21 are included in the boiler furnace protection system 12, the first pressure transmitter 4 and the seventh pressure transmitter 10 are connected with the first AI card 14, the second pressure transmitter 5 and the eighth pressure transmitter 11 are connected with the second AI card 15, the third pressure transmitter 8 and the fifth pressure transmitter 6 are connected with the third AI card 16, the fourth pressure transmitter 9 and the sixth pressure transmitter 7 are connected with the fourth AI card 17, the first AI card 14, the second AI card 15, the third AI card 16 and the fourth AI card 17 are connected with the two-out-of-four logic function block 18, the two-out-of-four logic function block 18 is connected with the first DO card 19, the second DO card 20 and the third DO card 21, and the first DO card 19, the second DO card 20 and the third DO card 21 are connected with the boiler tripping relay cabinet 13.
[0021] The specific logic mode of the invention concept and the realization of the furnace pressure protection of the typical embodiment of the utility model is that the first pressure transmitter 4, the second pressure transmitter 5, the third pressure transmitter 8 and the fourth pressure transmitter 9 are divided into a group, are used for realizing the function of high two-value and low two-value pressure protection, are respectively connected to the input channels of the first AI card, the second AI card, the third AI card and the fourth AI card, are connected to the four-to-two logic function block as the input signals of a group of four-to-two logic, and logical judgment is carried out; when the analog signal of any two of the transmitters reaches the set value of high two-value or low two-value pressure, three protection action signals are output to the boiler tripping relay cabinet MFT through the four-to-two logic function block and the DO card to realize the protection action; similarly, the fifth pressure transmitter 6, the sixth pressure transmitter 7, the seventh pressure transmitter 10 and the eighth pressure transmitter 11 are divided into a group, are used for realizing the function of high three-value and low three-value pressure protection, are respectively connected to the input channels of the first AI card, the second AI card, the third AI card and the fourth AI card, are connected to the four-to-two logic function block as the input signals of a group of four-to-two logic, and logical judgment is carried out; when the value of any two of the transmitters reaches the set value of high three-value or low three-value pressure, three protection action signals are output to the boiler tripping relay cabinet MFT through the four-to-two logic function block and the DO card to realize the protection action; the above-mentioned mode divides the pressure protection instruments (high two-value and high three-value, low two-value and low three-value) of the same trend and sets them separately, that is, one group of transmitters realizes the four-to-two logic of high two-value and low two-value, and the other group of transmitters realizes the four-to-two logic of high three-value and low three-value, so that the consequence that the whole furnace pressure grading protection ability is completely lost when the instruments of the same trend are simultaneously disabled due to the common reason is avoided.
[0022] In order to further embody the technical effect of the utility model, the following provides an optimized redundant fault-tolerant judgment mechanism:
[0023] 1. Four-redundant lower (when four pressure transmitters in a group of pressure transmitters are normal) four-to-two logic scheme, first, the two transmitters of each group measuring the pressure of the same side of the furnace are judged by logical "or", that is, when the value of any one of the two transmitters reaches the set value, it is considered that the pressure of the same side is out of limit, and then the judgment results of the two sides are judged by logical "and", that is, when the pressure of the two sides is out of limit at the same time, it is judged that the pressure of the furnace is out of limit, and the protection action output is triggered;
[0024] 2. When the input signal quality is judged, if the value of one of the four transmitters of a group is obviously deviated from the values of the other three transmitters, the value of the transmitter is shielded and instrument fault alarm is carried out at the same time, and the three-redundant mode is entered to carry out three-to-two logic judgment, when the values of any two of the normal three transmitters reach the set value, it is judged that the pressure of the furnace is out of limit, and the protection action output is triggered.
[0025] In summary, the boiler furnace pressure protection is one of the most important protection circuits of the thermal power plant, which needs to avoid the protection misoperation caused by the instrument or circuit failure to affect the normal production, and also needs to avoid the protection refusal to cause more serious accident consequences when the pressure is over limit. The boiler furnace pressure protection configuration scheme provided by the utility model adopts a pressure transmitter to replace a general pressure switch as a sensor instrument used for pressure protection, can judge the quality of the instrument signal through real-time reading, timely discovers the instrument failure to process, adopts a "four-to-two" to replace a "three-to-two" logical judgment mode, can avoid the problem that the instantaneous fluctuation of the single-side pressure leads to the boiler protection misoperation, separates the pressure protection instruments with the same trend (high two values and high three values, low two values and low three values) to be arranged, avoids the consequence that the classification protection ability of the furnace pressure is completely lost when the detection instruments with the same trend are simultaneously invalid due to the common reason, makes the furnace pressure protection have higher safety and reliability, and thus guarantees the safe and stable operation of the boiler system of the thermal power plant.
Claims
1. A coal-fired power plant boiler furnace pressure protection system, characterized by, The boiler furnace (1) is divided into furnace left side (2) and furnace right side (3), the first pressure transmitter (4), the second pressure transmitter (5), the fifth pressure transmitter (6) and the sixth pressure transmitter (7) are connected to the boiler furnace left side (2), the third pressure transmitter (8), the fourth pressure transmitter (9), the seventh pressure transmitter (10) and the eighth pressure transmitter (11) are connected to the boiler furnace right side (3), the first pressure transmitter (4), the second pressure transmitter (5), the fifth pressure transmitter (6), the sixth pressure transmitter (7), the third pressure transmitter (8), the fourth pressure transmitter (9), the seventh pressure transmitter (10) and the eighth pressure transmitter (11) are connected with the boiler furnace protection system (12), the boiler furnace protection system (12) is connected with the boiler trip relay cabinet (13).
2. The coal-fired power plant boiler furnace pressure protection system of claim 1, wherein, The first AI card (14), the second AI card (15), the third AI card (16), the fourth AI card (17), the four-to-two logic function block (18), the first DO card (19), the second DO card (20), the third DO card (21) are included in the boiler furnace protection system (12), the first pressure transmitter (4), the seventh pressure transmitter (10) are connected with the first AI card (14), the second pressure transmitter (5), the eighth pressure transmitter (11) are connected with the second AI card (15), the third pressure transmitter (8), the fifth pressure transmitter (6) are connected with the third AI card (16), the fourth pressure transmitter (9), the sixth pressure transmitter (7) are connected with the fourth AI card (17), the first AI card (14), the second AI card (15), the third AI card (16), the fourth AI card (17) are connected with the four-to-two logic function block (18), the four-to-two logic function block (18) is connected with the first DO card (19), the second DO card (20), the third DO card (21), the first DO card (19), the second DO card (20), the third DO card (21) are connected with the boiler trip relay cabinet (13).
3. A coal-fired power plant boiler furnace pressure protection system according to claim 1 or 2, characterised in that, It includes a first protection circuit for realizing pressure high binary and pressure low binary protection, and a second protection circuit for realizing pressure high ternary and pressure low ternary protection; the first pressure transmitter (4), the second pressure transmitter (5), the third pressure transmitter (8), the fourth pressure transmitter (9) are connected in the first protection circuit; the fifth pressure transmitter (6), the sixth pressure transmitter (7), the seventh pressure transmitter (10), the eighth pressure transmitter (11) are connected in the second protection circuit.