A closed conveying system and method for circulating fluidized bed boiler coal ash
By adopting a system that uses a shared Roots blower and ash conveying pipeline in a circulating fluidized bed boiler, and combining automation and manual control, the problems of complex and poor safety of coal ash collection systems in small and medium-sized boilers have been solved, and efficient and reliable coal ash conveying has been achieved.
Patent Information
- Application Number
- CN202211650227.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-21
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2042-12-21
AI Technical Summary
The coal ash treatment system for small and medium-sized circulating fluidized bed boilers has problems such as complex collection, low degree of automation and poor safety. In particular, in boilers with settling chambers, the collection of coal ash by burning multiple coal ash makes the system complex and occupies a large area.
A system is adopted that uses a single Roots blower and ash conveying pipeline, combined with a material level detection component and an electrically controlled valve, to achieve fully automated collection of coal ash in the settling chamber and dust collector. Manual knife gate valves are installed at key locations to ensure system reliability. Temperature and pressure transmitters are used to regulate ash temperature and air pressure, and vibrators are installed to prevent blockage.
The system is simple, highly automated, reliable and stable, reducing system complexity and footprint, and ensuring the safe transport of high-temperature ash.
Smart Images
Figure CN116025894B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of boiler ash removal, in particular to a circulating fluidized bed boiler coal ash closed conveying system and method. BACKGROUND
[0002] Circulating fluidized bed is a clean coal combustion technology that gradually emerged in China in the late 1990s. After nearly three decades of development, it has been widely used in the oil, power, chemical and other industries.
[0003] During the combustion process of the fluidized bed boiler, large-particle slag and small-particle coal ash are produced. When the coal ash is washed against the heat transfer surface by the flue gas, part of the coal ash will fall into the settling chamber under the action of gravity, and the other part of the coal ash will enter the dust collector with the flue gas. After treatment by the dust collector, the flue gas is discharged into the atmosphere, and the coal ash is collected and stored in the dust collector bottom ash bin.
[0004] In small and medium-sized circulating fluidized bed systems, the traditional coal ash treatment method mainly relies on the warehouse pump or material seal pump to convey the coal ash to the ash storage for storage, and then the tank truck is transported for processing. For boilers with settling chambers, the dust collector and the settling chamber have multiple points of coal ash collection, which causes the collection system to be complex, the degree of automation to be low, the land occupation to be large, and the safety to be poor. SUMMARY
[0005] The present application proposes a circulating fluidized bed boiler coal ash closed conveying system and method, which uses a simple and easy method to collect the dust collected in the settling chamber and dust collector of a boiler at the same time with a set of system, and the system is simple, has low degree of automation, and is reliable in operation.
[0006] The technical scheme of the present application is realized as follows:
[0007] According to one aspect of the present application, there is provided a circulating fluidized bed boiler coal ash closed conveying system, comprising a boiler convection heating surface and a flue shaft connected with the boiler convection heating surface, the bottom of the boiler convection heating surface is arranged with a settling chamber, the settling chamber is divided into a first settling chamber and a second settling chamber, the bottom of the first settling chamber is connected with a first ash discharge pipe, the bottom of the second settling chamber is connected with a second ash discharge pipe, the bottom of the first ash discharge pipe is installed with a first ash discharge gate valve, and the bottom of the second ash discharge pipe is installed with a second ash discharge gate valve; the first ash discharge pipe is connected with an ash collecting bin through a first bypass pipe, the second ash discharge pipe is connected with the ash collecting bin through a second bypass pipe, the top of the ash collecting bin is connected with the flue shaft through an exhaust pipe, the bottom of the ash collecting bin is connected with a first sealing pump through a connecting pipe, and the discharge port of the first sealing pump is connected with an ash storage through a pneumatic ash conveying pipe; the bottom of the flue shaft is connected with a dust collector through an inlet smoke pipe, the smoke outlet of the dust collector is connected with a chimney through a smoke discharge pipe, and an induced draft fan is arranged on the smoke discharge pipe; the ash outlet of the dust collector is connected with a second sealing pump through a third ash discharge pipe; the discharge port of the second sealing pump is communicated with the air inlet of the first sealing pump, and the air inlet of the second sealing pump is connected with a Roots blower.
[0008] The first settling chamber is provided with a first material level detection assembly, the second settling chamber is provided with a third material level detection assembly, the ash collecting bin is provided with a second material level detection assembly, and the dust collector is provided with a fourth material level detection assembly and a fifth material level detection assembly; the first bypass pipe is provided with a first electric control valve, the exhaust pipe is provided with a second electric control valve, the connecting pipe is provided with a third electric control valve, the second bypass pipe is provided with a fourth electric control valve, the third ash discharge pipe is provided with a fifth electric control valve, and the fourth ash discharge pipe is provided with a sixth electric control valve; the first material level detection assembly, the second material level detection assembly, the third material level detection assembly, the fourth material level detection assembly, the fifth material level detection assembly, the first electric control valve, the second electric control valve, the third electric control valve, the fourth electric control valve, the fifth electric control valve, the sixth electric control valve, the first sealing pump, the second sealing pump, the dust collector, and the Roots blower are respectively connected with a controller of the conveying system.
[0009] The present application conveys the coal ash in the settling chamber and the dust collector by sharing one Roots blower and one ash conveying pipeline, reduces the complexity of the conveying system, reduces the occupied space of the conveying system, and is convenient to operate and maintain; the material level detection assemblies are arranged in the settling chamber, the ash collecting bin and the dust collector, and the electric control valves are arranged on the first bypass pipe, the second bypass pipe, the third ash discharge pipe, the fourth ash discharge pipe, the exhaust pipe and the connecting pipe, so that the corresponding electric control valves are automatically opened for ash discharge according to the accumulation amount of the coal ash in the settling chamber, the ash collecting bin and the dust collector, and the full-automatic operation of the conveying system is realized, and the system has high reliability and stability.
[0010] As a preferred scheme of the present application, the first material level detection component, the second material level detection component, the third material level detection component, the fourth material level detection component and the fifth material level detection component all comprise a high material level tuning fork switch and a low material level tuning fork switch; the first electric control valve, the second electric control valve, the third electric control valve, the fourth electric control valve, the fifth electric control valve and the sixth electric control valve are all pneumatic knife gate valves.
[0011] As a preferred scheme of the present application, a temperature transmitter is arranged on the pneumatic ash conveying pipe, and a pressure transmitter is arranged on the air outlet pipe of the Roots blower; by arranging the temperature transmitter on the pneumatic ash conveying pipe, the opening of the corresponding electric control valve can be adjusted according to the temperature data of the coal ash in each pipeline, so as to ensure that the temperature of the conveyed coal ash meets the temperature resistance requirement of the steel ash silo, and the safety risk of high-temperature coal ash entering the ash silo is solved; by arranging the pressure transmitter, the air pressure in the pipeline can be monitored, and the power of the Roots blower can be adjusted according to the air pressure, so as to ensure that the air pressure in the pipeline is controlled within a safe pressure range.
[0012] As a preferred scheme of the present application, a first manual knife gate valve is further arranged on the first bypass pipe, a second manual knife gate valve is arranged on the connecting pipe, a third manual knife gate valve is arranged on the second bypass pipe, a fourth manual knife gate valve is arranged on the third ash conveying pipe, and a fifth manual knife gate valve is arranged on the fourth ash conveying pipe; by arranging multiple manual knife gate valves, the manual control of the ash conveying process in the settling chamber and the dust collector can be realized, and when the automatic control fails, the ash conveying can be carried out by manual control, so as to ensure the reliability and stability of the conveying system.
[0013] As a preferred scheme of the present application, a vibrator is arranged on the outer wall of the bottom of the ash collecting bin, and the vibrator is connected with the controller; by arranging the vibrator on the bottom of the ash collecting bin, the problem that the material level detection component cannot accurately detect the data due to the adhesion of coal ash on the inner wall of the ash collecting bin can be avoided, and the problem of blockage of the ash collecting bin during ash discharge can also be avoided.
[0014] As a preferred scheme of the present application, the air inlet of the second sealing pump is further connected with a standby Roots blower through a pipeline, a seventh electric control valve is arranged on the communication pipeline between the standby Roots blower and the second sealing pump, and the seventh electric control valve is connected with the controller; the Roots blower and the standby Roots blower can be used alternately, so as to avoid fatigue or failure of one blower due to long-time operation.
[0015] As a preferred scheme of the present application, the boiler convection heating surface comprises a superheater, a convection tube and a lower steam drum; and the inlet of the flue shaft is provided with an economizer and an air preheater.
[0016] According to another aspect of the present application, a closed conveying method of coal ash of a circulating fluidized bed boiler is provided, comprising the following steps:
[0017] When any one or more of the first material level detection component (17), the third material level detection component (46), the fourth material level detection component (19), and the fifth material level detection component (26) generates a high material level detection signal, the Roots blower (16) is started after a delay T1;
[0018] The following takes the first material level detection component and the fifth material level detection component as examples for illustration:
[0019] If the first material level detection component generates a high material level detection signal, the second electric control valve is opened after a delay T2, and the first electric control valve is opened after a delay T3 after the second electric control valve is opened; after the first electric control valve is opened, the vibrator installed on the outer sidewall of the ash collecting bin is periodically operated;
[0020] When the second material level detection component generates a high material level detection signal, the first electric control valve and the vibrator are closed after a delay T4; the second electric control valve is closed after a delay T5 after the first electric control valve is closed; the third electric control valve is opened, and the vibrator is periodically operated after the second material level detection component generates a high material level detection signal for T6;
[0021] When the second material level detection component generates a low material level detection signal, the third electric control valve and the vibrator are closed;
[0022] At this time, when the first material level detection component generates a low material level detection signal, the first electric control valve is closed after a delay T7; the second electric control valve is closed after a delay T8 after the first electric control valve is closed; if the third material level detection component, the fourth material level detection component, and the fifth material level detection component all do not generate a high material level detection signal, the Roots blower is closed after a delay T9;
[0023] If the fifth material level detection component generates a high material level detection signal, the sixth electric control valve is opened; when the fifth material level detection component generates a low material level detection signal, the sixth electric control valve is closed after a delay T10; at this time, if the first material level detection component, the third material level detection component, and the fourth material level detection component all do not generate a high material level detection signal, the Roots blower is closed after a delay T9.
[0024] As a preferred scheme of the present application, the opening degree of the third electric control valve, the opening degree of the fifth electric control valve, and the opening degree of the sixth electric control valve are controlled according to a temperature transmitter on the pneumatic ash conveying pipe; the higher the temperature, the smaller the opening degree of the electric control valve.
[0025] Advantages
[0026] Compared with the prior art, the present application has the following advantages:
[0027] (1) The present application realizes the conveying of the coal ash in the conveying sink chamber and the dust collector through sharing one Roots blower and one ash conveying pipe, reduces the complexity of the conveying system, reduces the occupied space of the conveying system, and facilitates the system operation and maintenance;
[0028] (2) The present application realizes the automatic operation of the conveying system by setting the material level detection assembly in the settling chamber, the ash collecting bin and the dust collector, and setting the electric control valve on the first bypass pipe, the connecting pipe, the second bypass pipe, the third ash discharging pipe and the fourth ash discharging pipe, and automatically opening the corresponding electric control valve to discharge ash according to the accumulation amount of the coal ash in the settling chamber, the ash collecting bin and the dust collector, so that the system operation reliability and stability are high;
[0029] (3) The present application realizes the regulation of the amount of coal ash entering the ash conveying pipeline 9 during the ash conveying process by installing the temperature transmitter 28 on the ash conveying pipeline 9, so that the conveying coal ash temperature meets the temperature resistance requirement of the steel ash storage, and the safety risk of high-temperature coal ash entering the ash storage is solved;
[0030] (4) The present application realizes the manual control of the ash discharging process in the settling chamber and the dust collector by setting the multiple manual knife gate valves, so that the ash can be discharged by manual control when the automatic control fails, and the reliability and stability of the conveying system operation are ensured. BRIEF DESCRIPTION OF DRAWINGS
[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.
[0032] Figure 1 It is a structural schematic diagram of the present application, a closed conveying system for coal ash of circulating fluidized bed boiler;
[0033] In the figure: 1, flue shaft; 2, first settling chamber; 3, second settling chamber; 4, first ash discharge pipe; 5, ash collecting bin; 6, exhaust pipe; 7, connecting pipe; 8, first sealing pump; 9, pneumatic ash conveying pipe; 10, ash storage; 11, dust collector; 12, chimney; 13, induced draft fan; 14, third ash discharge pipe; 15, second sealing pump; 16, Roots blower; 17, first material level detection assembly; 18, second material level detection assembly; 19, fourth material level detection assembly; 20, first electric control valve; 21, second electric control valve; 22, third electric control valve; 23, sixth electric control valve; 24, first ash discharge gate valve; 25, first bypass pipe; 26, fifth material level detection assembly; 27, fifth manual gate valve; 28, temperature transmitter; 29, pressure transmitter; 30, third manual gate valve; 31, second manual gate valve; 32, fourth manual gate valve; 33, vibrator; 34, standby Roots blower; 35, seventh electric control valve; 36, superheater; 37, convection pipe; 38, lower steam drum; 39, economizer; 40, air preheater; 41, dust removal assembly; 42, first manual gate valve; 43, second ash discharge gate valve; 44, second bypass pipe; 45, fourth electric control valve; 46, third material level detection assembly; 47, fifth electric control valve; 48, fourth ash discharge pipe; 49, second ash discharge pipe. DETAILED DESCRIPTION
[0034] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.
[0035] REFERENCE Figure 1As shown, the embodiment provides a closed conveying system for coal ash of circulating fluidized bed boiler, which comprises a boiler convection heating surface and a flue shaft 1 connected with the boiler convection heating surface, the boiler convection heating surface comprises a superheater 36, a convection tube 37 and a lower steam drum 38; the inlet of the flue shaft 1 is provided with an economizer 39 and an air preheater 40; the bottom of the boiler convection heating surface is provided with a first settling chamber 2 and a second settling chamber 3, the bottom of the first settling chamber 2 is connected with a first ash discharge pipe 4, the bottom of the second settling chamber 3 is connected with a second ash discharge pipe 49, the bottom of the first ash discharge pipe 4 is provided with a first ash discharge gate valve 24 (normally closed state), the bottom of the second ash discharge pipe 49 is provided with a second ash discharge gate valve 43; the first ash discharge pipe 4 is connected with an ash collecting bin 5 through a first bypass pipe 25; the second ash discharge pipe 49 is connected with the ash collecting bin 5 through a second bypass pipe 44; the top of the ash collecting bin 5 is connected with the flue shaft 1 through an exhaust pipe 6, the bottom of the ash collecting bin 5 is connected with a first sealing pump 8 through a connecting pipe 7, the discharge outlet of the first sealing pump 8 is connected with an ash storage 10 (the top of the ash storage 10 is also provided with a dust removal assembly 41) through a pneumatic ash conveying pipe 9; the bottom of the flue shaft 1 is connected with a dust remover 11 through a smoke inlet pipe, the smoke outlet of the dust remover 11 is connected with a chimney 12 through a smoke discharge pipe, the smoke discharge pipe is provided with an induced draft fan 13; the ash outlet of the dust remover 11 is connected with a second sealing pump 15 through a third ash discharge pipe 14 and a fourth ash discharge pipe 48; the discharge outlet of the second sealing pump 15 is communicated with the gas inlet of the first sealing pump 8, the gas inlet of the second sealing pump 15 is connected with a Roots blower 16.
[0036] The first settling chamber 2 is provided with a first material level detection assembly 17, the second settling chamber 3 is provided with a third material level detection assembly 46, the ash collecting bin 5 is provided with a second material level detection assembly 18, the dust remover 11 is provided with a fourth material level detection assembly 19 and a fifth material level detection assembly 26; the first bypass pipe 25 is provided with a first electric control valve 20, the exhaust pipe 6 is provided with a second electric control valve 21, the connecting pipe 7 is provided with a third electric control valve 22, the second bypass pipe 44 is provided with a fourth electric control valve, the third ash discharge pipe 14 is provided with a fifth electric control valve 47, the fourth ash discharge pipe 48 is provided with a sixth electric control valve 23, the first material level detection assembly 17, the second material level detection assembly 18, the third material level detection assembly 46, the fourth material level detection assembly 19, the fifth material level detection assembly 26, the first electric control valve 20, the second electric control valve 21, the third electric control valve 22, the fourth electric control valve 45, the fifth electric control valve 47, the sixth electric control valve 23, the seventh electric control valve 35, the first sealing pump 8, the second sealing pump 15, the dust remover 11, the Roots blower 16, the standby Roots blower 34, the temperature transmitter 28 and the pressure transmitter 29 are respectively connected with a controller (in this embodiment, the controller is a DCS control system) of the conveying system.
[0037] The embodiment transports the coal ash in the first sedimentation chamber 2, the second sedimentation chamber 3 and the dust collector 11 by sharing one Roots blower 16 and one pneumatic ash conveying pipe 9, reduces the complexity of the conveying system, reduces the occupied space of the conveying system, and facilitates the system operation and maintenance; the material level detection components are arranged in the first sedimentation chamber 2, the second sedimentation chamber 3, the ash collecting bin 5 and the dust collector 11, and the electric control valves are arranged on the first bypass pipe 25, the exhaust pipe 6, the connecting pipe 7, the second bypass pipe 44, the third ash discharge pipe 14 and the fourth ash discharge pipe 48, so that the corresponding electric control valves are automatically opened to discharge ash according to the accumulation of the coal ash in the first sedimentation chamber 2, the second sedimentation chamber 3, the ash collecting bin 5 and the dust collector 11, the fully automatic operation of the conveying system is realized, and the system operation has high reliability and stability.
[0038] As a preferred scheme of the embodiment, the first material level detection component 17, the second material level detection component 18, the third material level detection component 46, the fourth material level detection component 19 and the fifth material level detection component 26 all include a high material level tuning fork switch and a low material level tuning fork switch; and the first electric control valve 20, the second electric control valve 21, the third electric control valve 22, the fourth electric control valve 45, the fifth electric control valve 47, the sixth electric control valve 23 and the seventh electric control valve 35 are all pneumatic knife gate valves.
[0039] As a preferred scheme of the embodiment, the first bypass pipe 25 is further provided with a first manual knife gate valve 42, the connecting pipe 7 is provided with a second manual knife gate valve 31, the second bypass pipe 44 is provided with a third manual knife gate valve 30, the third ash discharge pipe 14 is provided with a fourth manual knife gate valve 32, and the fourth ash discharge pipe 48 is provided with a fifth manual knife gate valve 27; the above manual knife gate valves are all in an open state during operation; by arranging multiple manual knife gate valves, the manual control of the conveying system to discharge ash in the sedimentation chamber and the dust collector 11 can be realized, and when the automatic control fails, manual control can be used to discharge ash, thereby ensuring the reliability and stability of the conveying system operation.
[0040] As a preferred scheme of the embodiment, the bottom outer wall of the ash collecting bin 5 is provided with a vibrator 33, and the vibrator 33 is connected with the controller; by arranging the vibrator 33 at the bottom of the ash collecting bin 5, the problem that the coal ash adheres to the inner wall of the ash collecting bin 5 to cause inaccurate detection data of the material level detection component can be avoided, and the problem of material blockage during ash discharge of the ash collecting bin 5 can also be avoided.
[0041] As a preferred scheme of the embodiment, the air inlet of the second sealing pump 15 is further connected with a standby Roots blower 34 through a pipeline, the seventh electric control valve 35 is arranged on the communication pipeline of the second sealing pump 15 and the standby Roots blower 34, and the seventh electric control valve 35 is connected with the controller; the Roots blower 16 and the standby Roots blower 34 can be used alternately, so that fatigue or failure of one blower during long-time operation is avoided.
[0042] Corresponding to the above conveying system, the embodiment also provides a closed conveying method of coal-fired ash of a circulating fluidized bed boiler, including two modes of manual control and automatic control.
[0043] I. Manual control mode:
[0044] Click the "coal-fired ash manual ash removal" function key on the DCS control page of the boiler to start the Roots blower 16 or open the seventh electric control valve 35 to start the standby Roots blower 34, and the dust removal assembly 41 at the top of the ash bin 10 is operated, and the running time in the idle state is not less than 5 min, and the pipeline is purged.
[0045] In the system, the first manual knife gate valve 42, the second manual knife gate valve 31, the third manual knife gate valve 30, the fourth manual knife gate valve 32, and the fifth manual knife gate valve 27 are in the normally open state, and the first ash removal knife gate valve 24 and the second ash removal knife gate valve 43 are in the normally closed state.
[0046] A. Manual ash removal in the settling chamber
[0047] Taking the first settling chamber 2 manual ash removal operation as an example: start the Roots blower 16, run idle for 5 min, manually remove the ash in the settling chamber, open the second electric control valve 21 to exhaust the ash collection bin 5, and when the second electric control valve 21 shows that it is opened to the position, manually click to open the first electric control valve 20 on the DCS control page (to prevent smoke short circuit, the first electric control valve 20 on the first bypass pipe 25 and the fourth electric control valve 45 on the second bypass pipe 44 cannot be opened at the same time), so that the coal-fired ash in the first settling chamber 2 falls into the ash collection bin 5; when the high material level tuning fork switch in the ash collection bin 5 triggers the high material level signal, manually close the first electric control valve 20 and the second electric control valve 21 on the DCS control page.
[0048] Then open the third electric control valve 22 and adjust the ash removal opening degree to ensure that the display values of the temperature transmitter 28 and the pressure transmitter 29 on the pneumatic ash conveying pipe 9 are within the safe control range, and the coal-fired ash removal work in the settling chamber starts.
[0049] During the coal-fired ash removal process, the operator can manually click to control the opening of the vibrator 33 on the DCS control page to improve the ash removal efficiency, and when the low material level signal of the low material level tuning fork switch in the ash collection bin 5 is triggered and the high material level alarm of the first material level detection assembly 17 disappears, manually click to close the third electric control valve 22 on the DCS control page, the Roots blower 16 continues to run for 5 min to purge the conveying pipeline, and then the Roots blower 16 is stopped, and the dust removal assembly 41 at the top of the ash bin 10 is also stopped.
[0050] A. Manual ash removal in the dust collector
[0051] Take the third ash pipe manual ash as an example: start the roots blower 16, no load operation 5 min, manual dust cleaner 11 ash, when the fourth material level detection component 19 trigger high material level signal in the dust cleaner 11, manually click on the DCS control page to control the fifth electric control valve 47 to open, and adjust the ash opening degree, ensure that the display value of temperature transmitter 28 and pressure transmitter 29 is in the safe control range, the coal ash removal work in the dust cleaner 11 starts (the fifth electric control valve 47 and the sixth electric control valve 23 in the dust cleaner 11 cannot be opened at the same time).
[0052] When the fourth material level detection component 19 low material level tuning fork switch triggers low material level signal, manually click on the DCS control page to close the fifth electric control valve 47, the roots blower 16 continues to run for 5 min to blow the pneumatic ash pipe 9, and then stop the roots blower 16, and the dust removal component 41 on the top of the ash bin 10 stops running.
[0053] II. Automatic control mode
[0054] A. Take the first material level detection component 17 (trigger signal) automatic control as an example
[0055] Click the "automatic ash removal of coal ash" function key on the DCS control page, when any one of the first material level detection component 17, the third material level detection component 46, the fourth material level detection component 19 and the fifth material level detection component 26 appears high material level detection signal, the roots blower 16 starts after 120s delay, and the dust removal component 41 on the top of the ash bin 10 is started in turn, wherein the automatic ash removal of coal ash follows the principle of stack, adheres to the working mode of "first alarm first operation", that is, if the material level detection component of the first settling chamber 2 or the second settling chamber 3 appears high material level alarm signal first, the ash removal work of the settling chamber is carried out first, and if the material level detection component in the dust cleaner 11 appears high material level alarm signal first, the ash removal work of the dust cleaner 11 is carried out first.
[0056] When the first material level detection component 17 in the first settling chamber 2 triggers high material level signal, the second electric control valve 21 opens after 10s delay, and the first electric control valve 20 opens after 10s delay after the second electric control valve 21 opens. At this time, the coal ash in the settling chamber will fall into the ash collection bin 5 under the action of gravity; after the first electric control valve 20 is opened, the vibrator 33 installed on the outer side wall of the ash collection bin 5 vibrates for 5s every 60s.
[0057] When the second material level detection component 18 in the ash collection bin 5 triggers a high material level signal, the first electric control valve 20 is closed after a delay of 10 seconds; the second electric control valve 21 is closed after a delay of 10 seconds after the first electric control valve 20 is closed; the third electric control valve 22 is opened after 300 seconds when the second material level detection component 18 triggers a high material level signal; the vibrator 33 vibrates for 5 seconds every 60 seconds, and the ash in the ash collection bin 5 is discharged, and the coal ash in the ash collection bin 5 falls into the first sealing pump 8 and is pumped into the ash storage 10 through the pneumatic ash conveying pipe 9; during the process, the opening degree of the third electric control valve 22 is adjusted according to the detection value of the temperature transmitter 28 installed on the pneumatic ash conveying pipe 9, and the set value of the temperature transmitter 28 is 65-85°C; when the ash discharge temperature is lower than 65°C, the opening degree of the third electric control valve 22 is automatically increased; when the ash discharge temperature is higher than 85°C, the opening degree of the third electric control valve 22 is automatically decreased; when the second material level detection component 18 in the ash collection bin 5 triggers a low material level signal, the third electric control valve 22 and the vibrator 33 are closed. If the first material level detection component 17 in the first settling chamber 2 does not trigger a low material level signal after the ash collection bin 5 completes a coal ash discharge operation, the operation is repeated once again.
[0058] If the first material level detection component 17 in the first settling chamber 2 triggers a low material level signal during the process of discharging ash from the first settling chamber 2 to the ash collection bin 5, the first electric control valve 20 and the vibrator 33 are closed after a delay of 10 seconds; the second electric control valve 21 is closed after a delay of 10 seconds after the first electric control valve 20 is closed; if the high material level signal is not triggered by the high material level tuning fork switch in the ash collection bin 5 at this time, the ash discharge operation of the first settling chamber 2 is completed; if the high material level signal is not triggered by any material level detection component in the second settling chamber 3 and the dust collector 11 at this time, the Roots blower 16 is stopped after a delay of 120 seconds, and the dust removal component 41 at the top of the ash storage 10 is also stopped; if the high material level signal is triggered by any material level detection component in the second settling chamber 3, the ash collection bin 5, and the dust collector 11, the ash discharge operation of the next trigger point is performed after a delay of 60 seconds.
[0059] B. Taking the automatic control of the fifth material level detection component 26 (trigger signal) as an example
[0060] When the fifth material level detection component 26 in the dust collector 11 triggers a high material level signal, the Roots blower 16 is started after a delay of 120 seconds, and the dust removal component 41 at the top of the ash storage 10 is automatically started, and the sixth electric control valve 23 is automatically opened; the opening degree of the sixth electric control valve 23 is adjusted according to the detection value of the temperature transmitter 28 installed on the pneumatic ash conveying pipe 9, and the set value of the temperature transmitter 28 is 65-85°C; when the ash discharge temperature is lower than 65°C, the opening degree of the sixth electric control valve 23 is increased; when the ash discharge temperature is higher than 85°C, the opening degree of the sixth electric control valve 23 is decreased.
[0061] When the fifth material level detection assembly 26 in the dust remover 11 triggers a low material level signal, the sixth electric control valve 23 is closed after a delay of 10s; at this time, if the first material level detection assembly 17, the third material level detection assembly 46 and the fourth material level detection assembly do not trigger a high material level signal, the Roots blower 16 is stopped after a delay of 120s, and the dust removal assembly 41 at the top of the ash storage 10 is stopped at the same time; if one of the first material level detection assembly 17, the third material level detection assembly 46 and the fourth material level detection assembly triggers a high material level signal, the next triggering point is arranged for ash removal after a delay of 60s.
[0062] In the process of coal ash removal, if the Roots blower 16 is abnormally stopped, an alarm is sent on the DCS control interface, and the seventh electric control valve 35 is opened after a delay of 5s to start the standby Roots blower 34 to restore the coal ash removal operation.
[0063] The pressure transmitter 29 installed on the pneumatic ash conveying pipe 9 sets the pressure alarm range to 30kPa-50kPa; when the system pressure is lower than 30kPa or higher than 50kPa, an alarm is sent during the operation of the DCS control system, and lasts for 5min, and the Roots blower 16 or the standby Roots blower 34 is automatically stopped; the alarm setting value of the temperature transmitter 28 is 80℃; when the temperature of the conveyed coal ash is higher than 80℃, an alarm signal is sent by the system, and lasts for 5min, and the Roots blower 16 or the standby Roots blower 34 is automatically stopped.
[0064] The dust removal assembly 41 at the top of the ash storage 10 is interlocked with the Roots blower 16 and the standby Roots blower 34 to start and stop at the same time; when either the Roots blower 16 or the standby Roots blower 34 starts, the dust removal assembly 41 starts at the same time; when either the Roots blower 16 or the standby Roots blower 34 stops, the dust removal assembly 41 stops at the same time.
[0065] The above only describes the preferred embodiments of the present application and is not used to limit the present application; any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A closed ash conveying system of a circulating fluidized bed boiler, comprising a boiler convection heating surface and a flue shaft (1) connected to the boiler convection heating surface, the bottom of the boiler convection heating surface being provided with a first settling chamber (2) and a second settling chamber (3), characterized in that The bottom of the first settling chamber (2) and the second settling chamber (3) is respectively connected with the first ash discharge pipe (4) and the second ash discharge pipe (49), the bottom of the first ash discharge pipe (4) is provided with the first ash discharge gate valve (24), the bottom of the second ash discharge pipe (49) is provided with the second ash discharge gate valve (43), the first ash discharge pipe (4) is connected with the ash collecting bin (5) through the first bypass pipe (25), the second ash discharge pipe (49) is connected with the ash collecting bin (5) through the second bypass pipe (44), the top of the ash collecting bin (5) is connected with the flue shaft (1) through the exhaust pipe (6), the bottom of the ash collecting bin (5) is connected with the first sealing pump (8) through the connecting pipe (7), the discharge port of the first sealing pump (8) is connected with the ash storage (10) through the pneumatic ash conveying pipe (9); the bottom of the flue shaft (1) is connected with the dust collector (11) through the flue, the exhaust outlet of the dust collector (11) is connected with the chimney (12) through the flue, and the flue is provided with the induced draft fan (13); the ash discharge outlet of the dust collector (11) is connected with the second sealing pump (15) through the third ash discharge pipe (14) and the fourth ash discharge pipe (48); the discharge port of the second sealing pump (15) is communicated with the gas inlet of the first sealing pump (8), and the gas inlet of the second sealing pump (15) is connected with the Roots blower (16); The first settling chamber (2) is provided with the first material level detection assembly (17), the second settling chamber (3) is provided with the third material level detection assembly (46), the ash collecting bin (5) is provided with the second material level detection assembly (18), and the dust collector (11) is provided with the fourth material level detection assembly (19) and the fifth material level detection assembly (26); the first bypass pipe (25) is provided with the first electric control valve (20), the exhaust pipe (6) is provided with the second electric control valve (21), the connecting pipe (7) is provided with the third electric control valve (22), the second bypass pipe (44) is provided with the fourth electric control valve (45), the third ash discharge pipe (14) is provided with the fifth electric control valve (47), and the fourth ash discharge pipe (48) is provided with the sixth electric control valve (23); the first material level detection assembly (17), the second material level detection assembly (18), the third material level detection assembly (46), the fourth material level detection assembly (19), the fifth material level detection assembly (26), the first electric control valve (20), the second electric control valve (21), the third electric control valve (22), the fourth electric control valve (45), the fifth electric control valve (47), the sixth electric control valve (23), the first sealing pump (8), the second sealing pump (15), the dust collector (11) and the Roots blower (16) are connected with the controller of the conveying system respectively; The pneumatic ash conveying pipe (9) is provided with the temperature transmitter (28), and the exhaust pipe of the Roots blower (16) is provided with the pressure transmitter (29); the temperature transmitter (28) and the pressure transmitter (29) are connected with the controller respectively; The bottom outer wall of the ash collecting bin (5) is provided with the vibrator (33), and the vibrator (33) is connected with the controller; The conveying method of the conveying system comprises the following steps: When any one or more of the first material level detection component (17), the third material level detection component (46), the fourth material level detection component (19), and the fifth material level detection component (26) generates a high material level detection signal, the Roots blower (16) is started after a delay of T1; If the first material level detection component (17) generates a high material level detection signal, the second electric control valve (21) is opened after a delay of T2, and the first electric control valve (20) is opened after a delay of T3 after the second electric control valve (21) is opened; after the first electric control valve (20) is opened, the vibrator (33) installed on the outer wall of the ash collecting bin (5) is periodically operated; When the second material level detection component (18) generates a high material level detection signal, the first electric control valve (20) and the vibrator (33) are closed after a delay of T4; the second electric control valve (21) is closed after a delay of T5 after the first electric control valve (20) is closed; after the second material level detection component (18) generates a high material level detection signal for T6, the third electric control valve (22) is opened, and the vibrator (33) is periodically operated; When the second material level detection component (18) generates a low material level detection signal, the third electric control valve (22) and the vibrator (33) are closed; When the first material level detection component (17) generates a low material level detection signal, the first electric control valve (20) and the vibrator (33) are closed after a delay of T7; the second electric control valve (21) is closed after a delay of T8 after the first electric control valve (20) is closed; at this time, if the first material level detection component (17), the third material level detection component (46), the fourth material level detection component (19), and the fifth material level detection component (26) all do not generate a high material level detection signal, the Roots blower (16) is stopped after a delay of T9; If the fourth material level detection component (19) generates a high material level detection signal, the fifth electric control valve (47) is opened; when the fourth material level detection component (19) generates a low material level detection signal, the fifth electric control valve (47) is closed after a delay of T10; at this time, if the first material level detection component (17), the second material level detection component (18), and the fourth material level detection component (19) all do not generate a high material level detection signal, the Roots blower (16) is closed after a delay of T9; The third material level detection component (46) generates a high material level detection signal or a low material level detection signal, and the first material level detection component (17) generates a high material level detection signal or a low material level detection signal; the fifth material level detection component (26) generates a high material level detection signal or a low material level detection signal, and the fourth material level detection component (19) generates a high material level detection signal or a low material level detection signal.
2. A closed ash handling system for a circulating fluidized bed boiler as claimed in claim 1, characterized in that The first material level detection component (17), the second material level detection component (18), the third material level detection component (46), the fourth material level detection component (19), and the fifth material level detection component (26) all include a high material level detection fork switch and a low material level detection fork switch; the first electric control valve (20), the second electric control valve (21), the third electric control valve (22), the fourth electric control valve (45), the fifth electric control valve (47), and the sixth electric control valve (23) are all pneumatic knife gate valves.
3. A closed ash handling system for a circulating fluidized bed boiler as recited in claim 1, wherein, The first bypass pipe (25) is provided with a first manual knife gate valve (42), the connecting pipe (7) is provided with a second manual knife gate valve (31), the second bypass pipe (44) is provided with a third manual knife gate valve (30), the third ash discharge pipe (14) is provided with a fourth manual knife gate valve (32), and the fourth ash discharge pipe is provided with a fifth manual knife gate valve (27).
4. A closed ash handling system for a circulating fluidized bed boiler as recited in claim 1, wherein, The air inlet of the second material sealing pump (15) is connected with a standby Roots blower (34) through a pipeline, and the communication pipeline of the standby Roots blower (34) and the second material sealing pump (15) is provided with a seventh electric control valve (35), and the seventh electric control valve (35) is connected with the controller.
5. A closed ash handling system for a circulating fluidized bed boiler as recited in claim 1, wherein, The boiler convection heating surface comprises a superheater (36), a convection pipe (37) and a lower steam drum (38); the inlet of the flue shaft (1) is provided with an economizer (39) and an air preheater (40).
6. A closed ash handling system for a circulating fluidized bed boiler as recited in claim 1, wherein, The opening degree of the third electric control valve (22), the opening degree of the fifth electric control valve (47) and the opening degree of the sixth electric control valve (23) are determined according to the temperature transmitter (28) on the pneumatic ash conveying pipe (9), and the higher the temperature is, the smaller the opening degree of the electric control valve is.
Citation Information
Patent Citations
Equipment for pneumatic transportation of fly ash of refuse incinerator
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Circulating fluidized bed combustor
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