A circulating fluidized bed hot water boiler and control system

Abstract

The present application relates to circulating fluidized bed boiler control technical field, especially to a kind of circulating fluidized bed hot water boiler and control system, including equipment device and control device, equipment device contains coal feeder, cold air fan, fluidized bed hearth, temperature measuring component and flue gas hot air backflow bypass valve.Variable load regulation, control device first issues coal instruction, and opens bypass valve in the delay period when coal is not concentrated heat release, high-temperature flue gas is introduced into air inlet channel to act as fluidization power.When reaching the threshold of combustion delay time, close bypass valve and increase cold air fan volume, so that cold air takes away heat and coal concentrated heat release form physical hedge.The present application solves the bed temperature fluctuation problem caused by large delay of coal feeding and air supply, and ensures stable operation of boiler.

Description

Technical Field

[0001] This invention relates to the field of circulating fluidized bed boiler control technology, and in particular to a circulating fluidized bed hot water boiler and its control system. Background Technology

[0002] Circulating fluidized bed hot water boilers are clean coal combustion devices. In scenarios involving dynamic adjustment of heat load in centralized heating networks, the boiler system needs to adjust its heat output power in real time according to changes in external heat demand. This adjustment process heavily relies on the control system synchronously changing the coal feed rate and air supply rate. The coal feed rate determines the total amount of basic combustion materials input, while the air supply rate provides the oxygen required for coal combustion. The fluidized bed contains a large number of solid particles in a suspended fluidized state. When coal particles are added to the fluidized bed, they undergo a vigorous combustion reaction in this suspended state, releasing heat outwards. When the external centralized heating demand increases, the control system synchronously issues control commands to adjust the coal feeding mechanism and the blower, thereby achieving the operational objective of simultaneously increasing the supply of coal and air.

[0003] Existing technologies have inherent physical control limitations when performing dynamic load regulation operations. The coal feeding and air supply actions within the boiler system exhibit strong coupling and significant delays. Adjusting the blower speed can immediately change the aerodynamic field inside the fluidized bed; however, after coal is fed into the fluidized bed, it must undergo physical processes such as crushing and drying before reaching its combustion point. This physical transformation process consumes a significant amount of time, resulting in a severe lag in the heat release during fuel combustion. This leads to a large time difference between the control command issuance and the actual heat release. This time difference disrupts the heat balance within the fluidized bed, causing a significant technical challenge: drastic fluctuations in bed temperature during boiler load changes due to the strong coupling and large delay between coal feeding and air supply. Taking a load increase operation as an example, a sudden increase in external heating demand triggers an increase in heating power. The blower increases the air supply, causing a large amount of cold air to rapidly enter the fluidized bed. This rapid airflow carries away a large amount of heat accumulated inside the fluidized bed, leading to a rapid drop in bed temperature. As the newly added coal completes its preheating and enters the concentrated combustion stage, the concentrated heat release of a large amount of coal causes a sharp rise in bed temperature. The alternating violent temperature fluctuations disrupt the stable operation of the boiler system. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a circulating fluidized bed hot water boiler and its control system. This invention solves the technical problem of severe bed temperature fluctuations caused by strong coupling and large delay between coal feed and air supply when the boiler load changes.

[0005] To solve the above-mentioned technical problems, the specific contents of the present invention are as follows:

[0006] In a first aspect, the present invention provides a circulating fluidized bed hot water boiler, which includes an equipment device and a control device, wherein the control device is communicatively connected to the equipment device.

[0007] The equipment includes a coal feeder, a cold air blower, a fluidized bed furnace, a bed temperature measuring component, and a flue gas hot air recirculation bypass valve. The cold air blower is equipped with an air inlet duct and is connected to the fluidized bed furnace. The coal feeder is also connected to the fluidized bed furnace. The bed temperature measuring component is arranged in the fluidized bed furnace. The flue gas hot air recirculation bypass valve is connected at both ends to the tail exhaust port of the fluidized bed furnace and the air inlet duct of the cold air blower, respectively.

[0008] The control device includes a heat load command receiving module, an operating condition matching module, a delay threshold determination module, a coal feeding feedforward control module, and an air supply dynamic compensation module. The air supply dynamic compensation module has an internal timing unit built in.

[0009] The heat load command receiving module receives the dynamic load signal sent by the external pipe network and sends the dynamic load signal to the operating condition matching module;

[0010] The operating condition matching module matches the target coal feed rate and target air supply rate in the steady-state operation mapping table based on the dynamic load signal, and sends the target coal feed rate to the delay threshold determination module and the coal feed feedforward control module, and sends the target air supply rate to the air supply dynamic compensation module.

[0011] The delay threshold determination module obtains the initial temperature parameters collected by the bed temperature measurement component, matches the combustion delay time threshold in the hysteresis database based on the initial temperature parameters and the target coal feed rate, and sends the combustion delay time threshold to the air supply dynamic compensation module.

[0012] The coal feeding feedforward control module sends an adjustment command for the target coal feeding amount to the coal feeder, controls the new coal to enter the fluidized bed furnace, and generates a coal feeding execution signal to be sent to the air supply dynamic compensation module.

[0013] The air supply dynamic compensation module receives the coal feeding execution signal and starts the internal timing unit; when the current timing value output by the internal timing unit has not reached the combustion delay time threshold, the air supply dynamic compensation module sends an opening command to the flue gas hot air return bypass valve to introduce the high-temperature flue gas from the tail exhaust port of the fluidized bed furnace into the air inlet of the cold air blower; when the current timing value output by the internal timing unit reaches the combustion delay time threshold, the air supply dynamic compensation module sends an increase command to the target air supply volume to the cold air blower and a closing command to the flue gas hot air return bypass valve.

[0014] Furthermore, in the circulating fluidized bed hot water boiler of the present invention, the coal feeder is a variable frequency speed-regulating coal feeder, the cold air blower is an inlet guide vane regulating blower, the fluidized bed furnace is a fluidized bed dense phase zone furnace, the bed temperature measuring component is a multi-point array distributed thermocouple temperature measuring component, and the flue gas hot air return bypass valve is a servo-driven high-temperature regulating butterfly valve; the multi-point array distributed thermocouple temperature measuring component is installed on the side wall of the fluidized bed dense phase zone furnace; the servo-driven high-temperature regulating butterfly valve is installed on the connecting pipe connecting the tail flue gas outlet of the fluidized bed dense phase zone furnace and the air inlet of the inlet guide vane regulating blower; the variable frequency speed-regulating coal feeder is connected to the fluidized bed dense phase zone furnace.

[0015] Furthermore, in the circulating fluidized bed hot water boiler of the present invention, the heat load command receiving module is configured to: acquire the heating power setting status code issued by the external pipeline network; extract the load increment identifier from the heating power setting status code; extract the target heating power nominal value corresponding to the heating power setting status code according to the load increment identifier; and send the target heating power nominal value as a dynamic load signal to the operating condition matching module.

[0016] Furthermore, in the circulating fluidized bed hot water boiler of the present invention, the operating condition matching module is configured to: receive the target nominal heating power value; index and locate the target nominal heating power value in the steady-state operation mapping table, wherein the steady-state operation mapping table is pre-loaded with equipment operating status datasets corresponding to different nominal heating power values; obtain the target equipment operating status dataset; and extract the target coal feeding frequency command and the target air supply opening command from the target equipment operating status dataset.

[0017] Furthermore, in the circulating fluidized bed hot water boiler of the present invention, the operating condition matching module is also configured to: synchronously send the target coal feeding frequency command as the target coal feeding amount to the delay threshold determination module and the coal feeding feedforward control module; and send the target air supply opening command as the target air supply amount to the air supply dynamic compensation module.

[0018] Furthermore, in the circulating fluidized bed hot water boiler of the present invention, the delay threshold determination module is configured to: receive initial temperature parameters collected by the bed temperature measurement component; convert the initial temperature parameters into the current bed temperature range; receive the target coal feeding frequency command; use the current bed temperature range and the target coal feeding frequency command as bidirectional addressing indexes, and perform cross-comparison in a two-dimensional table of the hysteresis database; extract the combustion delay time threshold stored at the cross position of the two-dimensional table; and send the combustion delay time threshold to the air supply dynamic compensation module.

[0019] Furthermore, in the circulating fluidized bed hot water boiler of the present invention, the coal feeding feedforward control module is configured to: receive a target coal feeding frequency instruction; send the target coal feeding frequency instruction to the coal feeder; obtain the time node of the sending of the target coal feeding frequency instruction, generate a coal feeding action execution status code according to the sending time node; and send the coal feeding action execution status code as a coal feeding execution signal to the air supply dynamic compensation module.

[0020] Furthermore, in the circulating fluidized bed hot water boiler of the present invention, the air supply dynamic compensation module is configured to: receive a combustion delay time threshold and a coal feeding action execution status code; activate an internal timing unit after receiving the coal feeding action execution status code; and cyclically compare the current timing value output by the internal timing unit with the combustion delay time threshold.

[0021] Furthermore, in the circulating fluidized bed hot water boiler of the present invention, the air supply dynamic compensation module is configured to: in the first operating state, if the current timing value does not match the combustion delay time threshold, issue an opening execution command to the flue gas hot air return bypass valve, maintain the current opening state of the cold air blower, and introduce the high-temperature flue gas from the tail exhaust port of the fluidized bed furnace into the air inlet of the cold air blower through the flue gas hot air return bypass valve; in the second operating state, if the current timing value matches the combustion delay time threshold, simultaneously issue a closing execution command to the flue gas hot air return bypass valve, and issue a target air supply opening command to the cold air blower.

[0022] Secondly, the present invention provides a circulating fluidized bed hot water boiler control system, which is applied to a circulating fluidized bed hot water boiler as described above. The system includes a control system and equipment connected in communication. The equipment includes a coal feeder, a cold air blower, a fluidized bed furnace, a bed temperature measuring component, and a flue gas hot air recirculation bypass valve. The cold air blower is provided with an air inlet duct and is connected to the fluidized bed furnace. The coal feeder is also connected to the fluidized bed furnace. The bed temperature measuring component is arranged in the fluidized bed furnace. The flue gas hot air recirculation bypass valve is connected at both ends to the tail exhaust port of the fluidized bed furnace and the air inlet duct of the cold air blower, respectively.

[0023] The control system includes: a command receiving module, a working condition matching module, a threshold determination module, a feedforward control module, and a dynamic compensation module. The dynamic compensation module has a built-in internal timing unit.

[0024] The instruction receiving module is configured to receive dynamic load signals sent by the external pipeline network and send the dynamic load signals to the operating condition matching module;

[0025] The operating condition matching module is configured to match the target coal feed rate and the target air supply rate in the steady-state operation mapping table based on the dynamic load signal, and send the target coal feed rate to the threshold determination module and the feedforward control module, and send the target air supply rate to the dynamic compensation module.

[0026] The threshold determination module is configured to acquire the initial temperature parameters collected by the bed temperature measurement component, match the combustion delay time threshold in the hysteresis database based on the initial temperature parameters and the target coal feed rate, and send the combustion delay time threshold to the dynamic compensation module.

[0027] The feedforward control module is configured to send adjustment instructions for the target coal feed rate to the coal feeder, control the new coal to enter the fluidized bed furnace, and generate a coal feeding execution signal to be sent to the dynamic compensation module.

[0028] The dynamic compensation module is configured to receive the coal feeding execution signal and start the internal timing unit; when the current timing value output by the internal timing unit has not reached the combustion delay time threshold, it sends an opening command to the flue gas hot air return bypass valve to introduce the high-temperature flue gas from the tail exhaust port of the fluidized bed furnace into the air inlet of the cold air blower; when the current timing value output by the internal timing unit reaches the combustion delay time threshold, it sends an increase command to the target air supply volume to the cold air blower and a closing command to the flue gas hot air return bypass valve.

[0029] Beneficial effects of this invention:

[0030] This invention effectively avoids drastic fluctuations in bed temperature during dynamic load adjustments by separating the timing of coal feeding and air supply. During the waiting period before the newly added coal undergoes physical drying and has yet to release heat, the control device opens the flue gas hot air return bypass valve, introducing high-temperature flue gas from the tail end of the fluidized bed furnace into the inlet duct of the cold air blower. This high-temperature flue gas serves as a supplementary power source for the fluidization of suspended solid particles, thus avoiding a sudden drop in bed temperature caused by prematurely adding cold air. When the current timing value output by the internal timing unit reaches the combustion delay time threshold, the system determines that the newly added coal has entered the concentrated heat release stage. At this point, the bypass valve is simultaneously closed, and an increase command is sent to the cold air blower. This ensures a physical heat balance between the heat carried away by the newly added cold air and the heat generated by the concentrated heat release of the newly added coal, guaranteeing the stable operation of the circulating fluidized bed hot water boiler during load changes. Attached Figure Description

[0031] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0032] Figure 1 This is a system architecture diagram of a circulating fluidized bed hot water boiler control system according to the present invention. Detailed Implementation

[0033] To make the technical solution of the present invention clearer, the present invention will be clearly and completely described below with reference to specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In a first aspect, the present invention provides a circulating fluidized bed hot water boiler, which includes an equipment device and a control device, wherein the control device is communicatively connected to the equipment device.

[0035] The equipment includes a coal feeder, a cold air blower, a fluidized bed furnace, a bed temperature measuring component, and a flue gas hot air recirculation bypass valve. The cold air blower is equipped with an air inlet duct and is connected to the fluidized bed furnace. The coal feeder is also connected to the fluidized bed furnace. The bed temperature measuring component is arranged in the fluidized bed furnace. The flue gas hot air recirculation bypass valve is connected at both ends to the tail exhaust port of the fluidized bed furnace and the air inlet duct of the cold air blower, respectively.

[0036] The control device includes a heat load command receiving module, an operating condition matching module, a delay threshold determination module, a coal feeding feedforward control module, and an air supply dynamic compensation module. The air supply dynamic compensation module has an internal timing unit built in.

[0037] The heat load command receiving module receives the dynamic load signal sent by the external pipe network and sends the dynamic load signal to the operating condition matching module;

[0038] The operating condition matching module matches the target coal feed rate and target air supply rate in the steady-state operation mapping table based on the dynamic load signal, and sends the target coal feed rate to the delay threshold determination module and the coal feed feedforward control module, and sends the target air supply rate to the air supply dynamic compensation module.

[0039] The delay threshold determination module obtains the initial temperature parameters collected by the bed temperature measurement component, matches the combustion delay time threshold in the hysteresis database based on the initial temperature parameters and the target coal feed rate, and sends the combustion delay time threshold to the air supply dynamic compensation module.

[0040] The coal feeding feedforward control module sends an adjustment command for the target coal feeding amount to the coal feeder, controls the new coal to enter the fluidized bed furnace, and generates a coal feeding execution signal to be sent to the air supply dynamic compensation module.

[0041] The air supply dynamic compensation module receives the coal feeding execution signal and starts the internal timing unit; when the current timing value output by the internal timing unit has not reached the combustion delay time threshold, the air supply dynamic compensation module sends an opening command to the flue gas hot air return bypass valve to introduce the high-temperature flue gas from the tail exhaust port of the fluidized bed furnace into the air inlet of the cold air blower; when the current timing value output by the internal timing unit reaches the combustion delay time threshold, the air supply dynamic compensation module sends an increase command to the target air supply volume to the cold air blower and a closing command to the flue gas hot air return bypass valve.

[0042] In the overall control architecture of a circulating fluidized bed hot water boiler, the data communication path between the control unit and the equipment is established through the construction of an independent data bus channel. Within the control unit, this data bus channel sends drive messages to the coal feeder, cold air blower, and flue gas hot air return bypass valve according to a fixed sampling period. Simultaneously, the data bus channel synchronously acquires real-time millivolt voltage signals fed back by the bed temperature measurement components located in the fluidized bed furnace. After data acquisition, the data bus channel sequentially executes calculation and processing tasks through the heat load command receiving module, operating condition matching module, delay threshold determination module, coal feedforward control module, and air supply dynamic compensation module.

[0043] The specific structural configuration and lower-level connections of the equipment are manifested in the coordinated distribution of physical components. Multi-point array distributed thermocouple temperature sensing components are embedded between the metal tube rows on the side walls of the fluidized bed dense phase zone furnace according to a height gradient array rule, used for multi-dimensional acquisition of temperature gradient values ​​within the furnace space. A servo-driven high-temperature regulating butterfly valve is installed on a connecting pipe via a high-temperature resistant flange; the connecting pipe connects the tail exhaust port of the fluidized bed dense phase zone furnace to the inlet guide vanes regulating the air intake of the blower. The servo-driven high-temperature regulating butterfly valve receives control voltage signals and adjusts the cross-sectional area of ​​the connecting pipe according to these signals. A variable frequency speed-regulating coal feeder is connected to the fluidized bed dense phase zone furnace, changing its speed according to frequency commands to adjust the amount of coal fed into the furnace.

[0044] The data parsing path of the heat load command receiving module includes several consecutive acquisition and calculation steps. First, the heat load command receiving module reads the hexadecimal heating power setting status code issued by the external pipe network according to a preset communication protocol. Then, it performs a bitwise AND operation on the heating power setting status code to extract the load increment identifier in the high-order data frame. If the load increment identifier shows a positive step value, the system extracts the corresponding megawatt-level target heating power nominal value from the low-order data frame of the heating power setting status code according to a conversion formula. Finally, the extracted target heating power nominal value is packaged into a dynamic load signal and sent to the operating condition matching module.

[0045] The operating condition matching module performs a data comparison step to complete the indexing and positioning process. The module receives the nominal target heating power value and inputs it into the steady-state operation mapping table using this value as the retrieval key. The steady-state operation mapping table's storage structure pre-loads data sets of equipment operating status corresponding to different nominal heating power values ​​in a key-value pair data format. By executing a hash lookup algorithm, the operating condition matching module matches the exact corresponding target equipment operating status data set. After matching, the system extracts the corresponding Hertz-level target coal feeding frequency command and the percentage-level target air supply opening command from the target equipment operating status data set.

[0046] After the operating condition matching module completes the extraction, it performs a multi-channel data synchronization and distribution step. To achieve synchronous data flow, the operating condition matching module constructs a parallel data distribution bus. Through the parallel data distribution bus, the target coal feeding frequency command is used as the target coal feeding amount and is synchronously written into the query register of the delay threshold determination module and the execution register of the coal feeding feedforward control module within the same system clock cycle. At the same time, the target air supply opening command is used as the target air supply volume and sent to the buffer storage area of ​​the air supply dynamic compensation module for later retrieval.

[0047] The delay threshold determination module is responsible for performing the parameter addressing process. First, it receives initial temperature parameters (in degrees Celsius) collected by the bed temperature measurement component. Then, based on a preset temperature upper and lower limit division matrix, it maps the initial temperature parameters into a specific current bed temperature range. Subsequently, the delay threshold determination module retrieves the target coal feeding frequency command from the buffer. In the two-dimensional table of the hysteresis database, the current bed temperature range is used as the vertical addressing index column, and the target coal feeding frequency command is used as the horizontal addressing index row for cross-coordinate point positioning. After positioning, the specific second-level combustion delay time threshold stored at the coordinate intersection position of the two-dimensional table is extracted and sent to the air supply dynamic compensation module.

[0048] The adjustment command issuance stage of the coal feeding feedforward control module includes control signal conversion and status marking steps. The coal feeding feedforward control module reads the received target coal feeding frequency command, converts it into a standard analog control voltage signal, and sends it to the coal feeder execution end. It synchronously calls the controller's system clock function to obtain the precise issuance time node of the analog control voltage signal output action. Based on the obtained issuance time node, it toggles and sets the default flag bit in the status register, thereby generating a coal feeding action executed status code. Finally, the coal feeding feedforward control module sends the set coal feeding action executed status code as a coal feeding execution signal to the logic input port of the air supply dynamic compensation module.

[0049] The start-up timing logic of the air supply dynamic compensation module is activated by a status flag. The module continuously scans its logic input ports, and upon receiving a message containing the combustion delay time threshold and a status code indicating that the coal feeding action has been executed, it generates a high-level trigger signal. This high-level trigger signal activates the timing unit built into the module, which begins accumulating a count at fixed steps. Simultaneously, a high-frequency cyclic comparison thread is established within the module's program structure. This thread reads the current timing value output by the timing unit in real time during each scan cycle and compares the difference between the current timing value and the received combustion delay time threshold.

[0050] The dual-state compensation determination mechanism of the air supply dynamic compensation module adopts an asynchronous control command issuance mechanism. In the first operating state, if the difference comparison result shows that the current timing value does not match the combustion delay time threshold, the air supply dynamic compensation module issues a fully open execution command to the flue gas hot air recirculation bypass valve; at the same time, it blocks the output channel of the target air supply opening command, maintaining the current opening state of the cold air blower unchanged. The fully open flue gas hot air recirculation bypass valve drives the high-temperature flue gas from the exhaust port at the tail of the fluidized bed furnace to be accelerated into the air inlet of the cold air blower.

[0051] In the second operating state, if the difference comparison result shows that the current timing value accurately matches the combustion delay time threshold, the air supply dynamic compensation module performs a switching action. The air supply dynamic compensation module simultaneously sends a complete blocking shutdown execution command to the flue gas hot air return bypass valve; and immediately releases the shielding restriction of the target air supply opening command output channel, and sends the target air supply opening command in the buffer storage area to the cold air blower to drive the execution end action.

[0052] Secondly, please refer to Figure 1 This invention provides a circulating fluidized bed hot water boiler control system, applied to a circulating fluidized bed hot water boiler as described above. The system includes a control system and equipment connected in communication. The equipment includes a coal feeder, a cold air blower, a fluidized bed furnace, a bed temperature measuring component, and a flue gas hot air recirculation bypass valve. The cold air blower is provided with an air inlet duct and is connected to the fluidized bed furnace. The coal feeder is also connected to the fluidized bed furnace. The bed temperature measuring component is arranged in the fluidized bed furnace. The flue gas hot air recirculation bypass valve is connected at both ends to the tail exhaust port of the fluidized bed furnace and the air inlet duct of the cold air blower, respectively.

[0053] The control system includes: a command receiving module, a working condition matching module, a threshold determination module, a feedforward control module, and a dynamic compensation module. The dynamic compensation module has a built-in internal timing unit.

[0054] The instruction receiving module is configured to receive dynamic load signals sent by the external pipeline network and send the dynamic load signals to the operating condition matching module;

[0055] The operating condition matching module is configured to match the target coal feed rate and the target air supply rate in the steady-state operation mapping table based on the dynamic load signal, and send the target coal feed rate to the threshold determination module and the feedforward control module, and send the target air supply rate to the dynamic compensation module.

[0056] The threshold determination module is configured to acquire the initial temperature parameters collected by the bed temperature measurement component, match the combustion delay time threshold in the hysteresis database based on the initial temperature parameters and the target coal feed rate, and send the combustion delay time threshold to the dynamic compensation module.

[0057] The feedforward control module is configured to send adjustment instructions for the target coal feed rate to the coal feeder, control the new coal to enter the fluidized bed furnace, and generate a coal feeding execution signal to be sent to the dynamic compensation module.

[0058] The dynamic compensation module is configured to receive the coal feeding execution signal and start the internal timing unit; when the current timing value output by the internal timing unit has not reached the combustion delay time threshold, it sends an opening command to the flue gas hot air return bypass valve to introduce the high-temperature flue gas from the tail exhaust port of the fluidized bed furnace into the air inlet of the cold air blower; when the current timing value output by the internal timing unit reaches the combustion delay time threshold, it sends an increase command to the target air supply volume to the cold air blower and a closing command to the flue gas hot air return bypass valve.

[0059] In this embodiment of the invention, under a dynamic adjustment scenario where a sudden cold wave causes a surge in the heat load of a centralized heating network, the external network dispatch center issues a heating power setting status code. The heating power setting status code includes a load increment identifier and a target nominal heating power value. The heat load command receiving module parses the heating power setting status code and extracts the dynamic load signal. Subsequently, the operating condition matching module inputs the target nominal heating power value as a retrieval key into the steady-state operation mapping table. The steady-state operation mapping table contains a pre-loaded dataset of equipment operating statuses. Through data retrieval and calculation, the operating condition matching module matches the target coal feeding frequency command for the variable frequency speed control coal feeder and the target air supply opening command for the inlet guide vane adjustment fan.

[0060] After coal is fed into the furnace, it undergoes physical drying and crushing endothermic processes. Adding cold air alone can cause a drop in bed temperature. To address the bed temperature fluctuation caused by the coupling delay between coal feed rate and air supply rate, a delay threshold determination module collects multi-dimensional millivolt voltage signals from a multi-point array of distributed thermocouple temperature measurement components in real time. These multi-dimensional millivolt voltage signals serve as initial temperature parameters and are mapped by the system to the current bed temperature range. In a two-dimensional table of the hysteresis database, the delay threshold determination module cross-references the current bed temperature range with the target coal feed frequency command as a bidirectional addressing index. After data addressing, the delay threshold determination module retrieves the combustion delay time threshold matching the current operating conditions.

[0061] The coal feeding feedforward control module sends the target coal feeding frequency command to the variable frequency speed-regulating coal feeder, controlling the feeder to add more coal into the fluidized bed dense phase zone furnace. Simultaneously, the coal feeding feedforward control module sends a coal action execution status code to the air supply dynamic compensation module. Upon receiving the status code, the air supply dynamic compensation module activates its built-in timing unit. During the waiting period before the newly added coal undergoes physical drying and has released heat, the current timing value output by the built-in timing unit does not reach the combustion delay time threshold. Before reaching the time threshold, the air supply dynamic compensation module sends a fully open command to the servo-driven high-temperature regulating butterfly valve. The fully open servo-driven high-temperature regulating butterfly valve introduces the high-temperature flue gas from the exhaust port at the tail of the fluidized bed furnace into the inlet duct of the cold air blower. The high-temperature flue gas acts as a supplementary power source for the fluidization of suspended solid particles inside the fluidized bed dense phase zone furnace, preventing a sudden drop in bed temperature due to premature addition of cold air.

[0062] When the current timing value output by the timing unit built into the air supply dynamic compensation module reaches the combustion delay time threshold, the air supply dynamic compensation module determines that the newly added coal has completed drying and entered the centralized heat release stage. Simultaneously, the air supply dynamic compensation module sends a closing command to the servo-driven high-temperature regulating butterfly valve and a target air supply opening command to the inlet guide vane regulating blower. The inlet guide vane regulating blower increases the cold air supply according to the target air supply opening command. The heat carried away by the newly added cold air and the heat generated by the centralized heat release of the newly added coal form a physical heat offset balance. This physical heat offset balance maintains the stable operation of the circulating fluidized bed hot water boiler during load regulation.

Claims

1. A circulating fluidized bed hot water boiler, characterized in that, It includes equipment and control devices, with the control devices communicating with the equipment. The equipment includes a coal feeder, a cold air blower, a fluidized bed furnace, a bed temperature measuring assembly, and a flue gas hot air recirculation bypass valve. The control device includes a heat load command receiving module, an operating condition matching module, a delay threshold determination module, a coal feeding feedforward control module, and an air supply dynamic compensation module. The air supply dynamic compensation module has an internal timing unit built in. The heat load command receiving module receives the dynamic load signal sent by the external pipe network and sends the dynamic load signal to the operating condition matching module; The operating condition matching module matches the target coal feed rate and target air supply rate in the steady-state operation mapping table based on the dynamic load signal, and sends the target coal feed rate to the delay threshold determination module and the coal feed feedforward control module, and sends the target air supply rate to the air supply dynamic compensation module. The delay threshold determination module obtains the initial temperature parameters collected by the bed temperature measurement component, matches the combustion delay time threshold in the hysteresis database based on the initial temperature parameters and the target coal feed rate, and sends the combustion delay time threshold to the air supply dynamic compensation module. The coal feeding feedforward control module sends an adjustment command for the target coal feeding amount to the coal feeder, controls the new coal to enter the fluidized bed furnace, and generates a coal feeding execution signal to be sent to the air supply dynamic compensation module. The air supply dynamic compensation module receives the coal feeding execution signal and starts the internal timing unit; when the current timing value output by the internal timing unit has not reached the combustion delay time threshold, the air supply dynamic compensation module sends an opening command to the flue gas hot air return bypass valve to introduce the high-temperature flue gas from the tail exhaust port of the fluidized bed furnace into the air inlet of the cold air blower; when the current timing value output by the internal timing unit reaches the combustion delay time threshold, the air supply dynamic compensation module sends an increase command to the target air supply volume to the cold air blower and a closing command to the flue gas hot air return bypass valve.

2. The circulating fluidized bed hot water boiler according to claim 1, characterized in that, The equipment includes a variable frequency speed-regulating coal feeder, an inlet guide vane regulating blower for cold air supply, a fluidized bed furnace for the dense phase zone of the fluidized bed, a multi-point array distributed thermocouple temperature measuring component for bed temperature measurement, and a servo-driven high-temperature regulating butterfly valve for flue gas hot air return bypass. The multi-point array distributed thermocouple temperature measuring component is installed on the side wall of the dense phase zone furnace of the fluidized bed. The servo-driven high-temperature regulating butterfly valve is installed on the connecting pipe between the tail flue gas outlet of the dense phase zone furnace of the fluidized bed and the air inlet of the inlet guide vane regulating blower. The variable frequency speed-regulating coal feeder is connected to the dense phase zone furnace of the fluidized bed.

3. The circulating fluidized bed hot water boiler according to claim 1, characterized in that, The heat load command receiving module is configured to: acquire the heating power setting status code issued by the external pipeline network; extract the load increment identifier from the heating power setting status code; extract the target heating power nominal value corresponding to the heating power setting status code based on the load increment identifier; and send the target heating power nominal value as a dynamic load signal to the operating condition matching module.

4. The circulating fluidized bed hot water boiler according to claim 3, characterized in that, The operating condition matching module is configured to: receive the target heating power nominal value; index and locate the target heating power nominal value in the steady-state operation mapping table, which is pre-loaded with equipment operating status datasets corresponding to different heating power nominal values; obtain the target equipment operating status dataset; and extract the target coal feeding frequency command and the target air supply opening command from the target equipment operating status dataset.

5. The circulating fluidized bed hot water boiler according to claim 4, characterized in that, The operating condition matching module is also configured to: synchronously send the target coal feeding frequency command as the target coal feeding amount to the delay threshold determination module and the coal feeding feedforward control module; and send the target air supply opening command as the target air supply amount to the air supply dynamic compensation module.

6. The circulating fluidized bed hot water boiler according to claim 5, characterized in that, The delay threshold determination module is configured to: receive the initial temperature parameters collected by the bed temperature measurement component; convert the initial temperature parameters into the current bed temperature range; receive the target coal feeding frequency command; use the current bed temperature range and the target coal feeding frequency command as bidirectional addressing indexes and perform cross-comparison in the two-dimensional table of the hysteresis database; extract the combustion delay time threshold stored at the cross position of the two-dimensional table; and send the combustion delay time threshold to the air supply dynamic compensation module.

7. The circulating fluidized bed hot water boiler according to claim 6, characterized in that, The coal feeding feedforward control module is configured to: receive the target coal feeding frequency instruction; send the target coal feeding frequency instruction to the coal feeder; obtain the time node of the sending of the target coal feeding frequency instruction, generate a coal feeding action execution status code based on the sending time node; and send the coal feeding action execution status code as a coal feeding execution signal to the air supply dynamic compensation module.

8. The circulating fluidized bed hot water boiler according to claim 7, characterized in that, The air supply dynamic compensation module is configured to: receive the combustion delay time threshold and the coal feeding action execution status code; start the internal timing unit after receiving the coal feeding action execution status code; and cyclically compare the current timing value output by the internal timing unit with the combustion delay time threshold.

9. The circulating fluidized bed hot water boiler according to claim 8, characterized in that, The air supply dynamic compensation module is also configured to: in the first operating state, if the current timing value does not match the combustion delay time threshold, issue an opening execution command to the flue gas hot air return bypass valve to maintain the current opening state of the cold air supply fan, and introduce the high-temperature flue gas from the tail exhaust port of the fluidized bed furnace into the air inlet of the cold air supply fan through the flue gas hot air return bypass valve; in the second operating state, if the current timing value matches the combustion delay time threshold, simultaneously issue a closing execution command to the flue gas hot air return bypass valve, and issue a target air supply opening command to the cold air supply fan.

10. A circulating fluidized bed hot water boiler control system, applied to a circulating fluidized bed hot water boiler as described in any one of claims 1 to 9, characterized in that, The system includes communication connections between the control system and the equipment. The equipment includes a coal feeder, a cold air blower, a fluidized bed furnace, a bed temperature measuring component, and a flue gas hot air recirculation bypass valve. The cold air blower is equipped with an air inlet and is connected to the fluidized bed furnace. The coal feeder is also connected to the fluidized bed furnace. The bed temperature measuring component is located in the fluidized bed furnace. The flue gas hot air recirculation bypass valve is connected at both ends to the tail exhaust port of the fluidized bed furnace and the air inlet of the cold air blower, respectively. The control system includes: a command receiving module, a working condition matching module, a threshold determination module, a feedforward control module, and a dynamic compensation module. The dynamic compensation module has a built-in internal timing unit. The instruction receiving module is configured to receive dynamic load signals sent by the external pipeline network and send the dynamic load signals to the operating condition matching module; The operating condition matching module is configured to match the target coal feed rate and the target air supply rate in the steady-state operation mapping table based on the dynamic load signal, and send the target coal feed rate to the threshold determination module and the feedforward control module, and send the target air supply rate to the dynamic compensation module. The threshold determination module is configured to acquire the initial temperature parameters collected by the bed temperature measurement component, match the combustion delay time threshold in the hysteresis database based on the initial temperature parameters and the target coal feed rate, and send the combustion delay time threshold to the dynamic compensation module. The feedforward control module is configured to send adjustment instructions for the target coal feed rate to the coal feeder, control the new coal to enter the fluidized bed furnace, and generate a coal feeding execution signal to be sent to the dynamic compensation module. The dynamic compensation module is configured to receive the coal feeding execution signal and start the internal timing unit; when the current timing value output by the internal timing unit has not reached the combustion delay time threshold, it sends an opening command to the flue gas hot air return bypass valve to introduce the high-temperature flue gas from the tail exhaust port of the fluidized bed furnace into the air inlet of the cold air blower; when the current timing value output by the internal timing unit reaches the combustion delay time threshold, it sends an increase command to the target air supply volume to the cold air blower and a closing command to the flue gas hot air return bypass valve.

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