A circulating fluidized bed boiler slag cooling and conveying system

Abstract

The present invention provides a circulating fluidized bed boiler slag cooling and conveying system. It is suitable for cooling, conveying and processing slag, including: a circulating fluidized bed boiler, wherein high-temperature slag is generated inside the circulating fluidized bed boiler; a steel belt slag cooler is used to cool and convey the high-temperature slag; a circulating air duct is connected to the tail of the steel belt slag cooler, and the circulating air duct is used to control the ambient air to exchange heat with the high-temperature slag, and recycle the heat of the high-temperature slag; the boiler tail flue can also be connected to the tail of the steel belt slag cooler, and the boiler tail flue is used to discharge the cooling air that has exchanged heat with the high-temperature slag to the atmosphere through a dust collector. The beneficial effects of the present invention are: the present invention is safe and stable in operation, has extremely low wear and tear, has high reliability, and can return most of the slag heat to the boiler, achieving the purpose of fully automated, environmentally friendly, resource-based cooling and conveying fluidized bed boiler slag.

Description

Technical Field

[0001] The invention relates to the technical field of fluidized bed boilers, and in particular to a slag cooling and conveying system for a circulating fluidized bed boiler. Background Art

[0002] At present, with the rapid development of science and technology and the continuous innovation of technology, the capacity of circulating fluidized bed boiler units is getting larger and larger, and the output of boiler slag is also increasing accordingly. For a long time, the slag cooling and transportation method commonly used in circulating fluidized bed boilers around the world is the wind and water combined roller slag cooler. The slag produced by circulating fluidized bed boilers usually contains high silica or other abrasive materials, and the slag temperature is 800-1100℃. Cooling and conveying slag through a roller slag cooler has the following disadvantages:

[0003] 1. Rapid and severe wear of equipment: Due to the relative movement between the high-temperature slag (800-1100℃) and the heat exchange fins and cooling water pipes inside the drum slag cooler, this will cause rapid and severe wear of the internal components of the drum slag cooler, affecting the advancement of the slag in the drum, thereby greatly reducing the slag discharge capacity of the slag cooler and seriously reducing the operating reliability of the slag cooler system.

[0004] 2. High failure rate of slag cooler: Due to the rapid and severe wear of the drum slag cooler components, the slag cooler often needs to be stopped for maintenance or replacement of worn parts, and even causes sudden shutdown of the slag cooler, thus affecting the overall stable operation of the fluidized bed boiler.

[0005] 3. Potential major safety risks to equipment and operators: Since the wind-water combined drum slag cooler is designed to cool the slag mainly through indirect contact with water, the rapid wear and leakage of the internal heat dissipation fins and cooling water pipes of the drum slag cooler will cause direct contact between the cooling water and the slag, thereby creating the risk of water vapor explosion, posing a major safety hazard to the operation of the equipment and operators.

[0006] 4. Low heat recovery rate: The slag temperature of circulating fluidized bed boiler is usually 800-1100℃, which contains a lot of heat. The existing drum slag cooler uses water and air for cooling, so it is difficult to recover the heat of the slag, resulting in huge heat loss.

[0007] 5. High water consumption: Since the Fengshui combined drum slag cooler mainly uses water as the cooling medium, and a large amount of water evaporates during the heat exchange between the hot slag and the cooling water, the water consumption is very high and cooling water must be replenished regularly. Summary of the invention

[0008] The invention provides a circulating fluidized bed boiler slag cooling and conveying system, which is used to solve the problems of fast and severe wear of circulating fluidized bed boiler equipment, high failure rate of slag cooler, low heat recovery rate and high water consumption in the prior art.

[0009] A circulating fluidized bed boiler slag cooling and conveying system, characterized in that it is suitable for cooling, conveying and processing slag, and comprises:

[0010] A circulating fluidized bed boiler, wherein high-temperature slag is produced inside the circulating fluidized bed boiler;

[0011] A steel belt slag cooler, the steel belt slag cooler is connected to the circulating fluidized bed boiler through a slag drop pipe; the steel belt slag cooler is used to cool and transport the high-temperature slag;

[0012] A circulating air duct, the circulating air duct is connected to the tail of the steel strip slag cooler, and the outlet of the circulating air duct is connected to the circulating fluidized bed boiler; the circulating air duct is used to control the heat exchange between the ambient air and the high-temperature slag, and to reuse the heat of the high-temperature slag;

[0013] The boiler tail flue is connected with the tail of the steel strip slag cooler, and the boiler tail flue is used to discharge the cooling air after the high-temperature slag is heat-exchanged to the atmosphere through the dust collector.

[0014] As an embodiment of the present invention: the circulating air duct includes a first dust removal device, a second dust removal device, a first fan, a second fan and a boiler secondary air duct; wherein,

[0015] The inlet end of the first dust removal device is connected to a first dust removal inlet valve;

[0016] The inlet end of the second dust removal device is connected to a third dust removal inlet valve;

[0017] The inlet ends of the first dust removal device and the second dust removal device are also connected to a second dust removal inlet valve;

[0018] The outlet end of the first dust removal device is connected to a first fan inlet valve, and the first fan inlet valve is connected to the inlet end of the first fan;

[0019] The outlet end of the second dust removal device is connected to a second fan inlet valve, and the second fan inlet valve is connected to the inlet end of the second fan;

[0020] The first fan outlet is connected to a first fan outlet valve;

[0021] The second fan air outlet is connected to a second fan outlet valve;

[0022] The first fan outlet valve and the second fan outlet valve are both connected to the boiler secondary air duct, and the air outlet of the boiler secondary air duct is connected to the circulating fluidized bed boiler.

[0023] As an embodiment of the present invention: the steel strip slag cooler comprises a first sub-steel strip slag cooler, a second sub-steel strip slag cooler and a main steel strip slag cooler;

[0024] The first steel strip slag cooler is connected to the boiler tail flue through the first tail flue cooling air duct; wherein,

[0025] The first tail flue cooling air duct is provided with a first cooling air duct valve;

[0026] The second steel strip slag cooler is connected to the boiler tail flue through a second tail flue cooling air duct; wherein,

[0027] The second tail flue cooling air duct is provided with a second cooling air duct valve;

[0028] The main steel belt slag cooler is connected to the boiler tail flue through the third tail flue cooling air duct; wherein,

[0029] The third tail flue cooling air duct is provided with a third cooling air duct valve.

[0030] As an embodiment of the present invention: the slag dropping pipe comprises at least a first slag dropping pipe and a second slag dropping pipe; wherein,

[0031] A distributor is provided at the bottom of the first slag dropping pipe and the second slag dropping pipe, an expansion compensator is provided on the top of the distributor, and a lower pressure transmitter is provided on the top of the expansion compensator; an isolation valve is provided on the top of the lower pressure transmitter, a thermocouple is provided above the isolation valve, and an upper pressure transmitter is provided above the thermocouple.

[0032] As an embodiment of the present invention: the interior of the slag dropping pipe is lined with refractory materials or ceramic anti-wear materials, and the exterior is installed with heat insulation materials, heat dissipation fins and a safety protection net.

[0033] As an embodiment of the present invention: the first steel strip slag cooler, the second steel strip slag cooler and the main steel strip slag cooler are all composed of metal conveyor belts and rollers; wherein,

[0034] An upper cover plate is provided on the upper portion of the shell;

[0035] The metal conveyor belt and the roller are arranged inside the shell, and the metal conveyor belt is arranged outside the roller; wherein,

[0036] There are at least two rollers;

[0037] The metal conveyor belts of the first steel strip slag cooler and the second steel strip slag cooler are also provided with a slag thickness regulating valve;

[0038] The slag thickness regulating valve comprises a regulating valve body, a regulating valve driving unit, a regulating valve plate and a regulating valve tensioning spring; wherein,

[0039] The regulating valve driving unit is arranged on the top of the regulating valve body, the regulating valve plate and the regulating valve tensioning spring are arranged inside the regulating valve body, and the two ends of the regulating valve tensioning spring are connected to the upper and lower ends of the regulating valve plate;

[0040] The lower part of the metal conveyor belt in the working direction is supported by a plurality of bearing round rollers along the entire width of the conveyor belt;

[0041] Both sides of the lower part of the metal conveyor belt in the return direction are supported by rotary circular rollers;

[0042] Guide rollers are designed and installed on both sides of the metal conveyor belt in the working direction and the return direction;

[0043] A conveyor belt lower spray device is arranged at the lower part of the metal conveyor belt.

[0044] As an embodiment of the present invention: the upper cover plate and both sides of the first steel strip slag cooler, the second steel strip slag cooler and the main steel strip slag cooler are equipped with metal heat dissipation fins, and the interior of the upper cover plate is equipped with cooling water pipes;

[0045] An upper cover plate spraying device is arranged in the middle of the upper cover plate; the cover plate spraying system is located directly above the metal conveyor belt, and the upper cover plate spraying device is supplied with water by a cooling water pipe.

[0046] As an embodiment of the present invention:

[0047] The first steel strip slag cooler, the second steel strip slag cooler and the main steel strip slag cooler are further provided with sealing brushes; a gap is provided between the bottom and side of the sealing brush and the metal conveyor belt; the sealing brush is made of high temperature resistant metal or non-metal;

[0048] A dustproof plate is installed between the working layer and the return layer of the metal conveyor belt;

[0049] The side of the steel belt slag cooler is also provided with a side air inlet.

[0050] As an embodiment of the present invention: the first sub-strip slag cooler, the second sub-strip slag cooler and the tail of the main steel strip slag cooler are provided with a first tensioning device and a second tensioning device; wherein,

[0051] The first tensioning device is a pneumatic tensioning device or a hydraulic tensioning device;

[0052] The second tensioning device is a mechanical tensioning device.

[0053] As an embodiment of the present invention: the system realizes cooling, conveying and processing of high-temperature slag through the following steps:

[0054] Step 1: The high-temperature slag inside the circulating fluidized bed boiler enters the slag drop pipe under the action of its own gravity;

[0055] Step 2: the expansion compensator of the slag falling pipe performs contraction or expansion compensation on the slag falling pipe according to the cold condition and hot condition of the circulating fluidized bed boiler;

[0056] Step 3: After the slag dropping pipe is compensated for shrinkage or expansion, the high-temperature slag falls into the metal conveyor belt of the steel belt slag cooler through the distributor;

[0057] Step 4: When the high-temperature slag falls onto the metal conveyor belt of the steel belt slag cooler, the slag thickness regulating valve calculates the material layer thickness at the maximum slag discharge amount according to the maximum slag discharge amount designed for the circulating fluidized bed boiler and the effective width of the metal conveyor belt, combined with the normal operating speed of the metal conveyor belt, and sets the slag material layer thickness by adjusting the distance between the regulating valve plate and the lower metal conveyor belt;

[0058] Step 5: controlling the upper cover spray device and the lower conveyor belt spray device to atomize and spray cool the metal conveyor belt according to the thickness of the slag layer;

[0059] Step 6: When the heat generated after cooling the circulating fluidized bed high-temperature slag in step 5 needs to be reused through the circulating air duct, step 7 is executed; when the heat generated after cooling the circulating fluidized bed high-temperature slag in step 5 does not need to be recovered to the boiler, but needs to be introduced into the atmosphere through the boiler tail flue, step 8 is executed;

[0060] Step 7: The first induced draft fan or the second induced draft fan introduces ambient air through the side air inlet, and the ambient air carries the heat in the steel belt slag cooler, passes through the first dust removal device or the second dust removal device for dust removal, and is then introduced into the boiler secondary air duct through the first induced draft fan or the second induced draft fan, and enters the circulating fluidized bed boiler until the high-temperature slag is cooled to a suitable safety temperature;

[0061] Step 8: The first induced draft fan or the second induced draft fan introduces ambient air through the side air inlet, and the ambient air carries the heat in the steel strip slag cooler and is discharged along the tail flue cooling air duct to the boiler tail flue, and is discharged to the atmosphere through the boiler dust collector and the chimney.

[0062] The beneficial effect of the present invention is that when the present invention processes the high-temperature slag in the fluidized bed, during the process of conveying the slag on the metal conveyor belt, since there is no relative movement between the slag and the metal conveyor belt, the wear of the metal conveyor belt can be almost ignored, and the service life of the metal conveyor belt is more than 10 years on average, which is about 5 times more than the life of the roller slag cooler. Therefore, the use of the technology of the present invention completely solves the problem of fast and serious wear of traditional technical equipment.

[0063] The boiler slag of the present invention is mainly cooled by cooling air sucked from the environment. Even if cooling water pipes are installed inside the upper cover plate of the slag cooler, these cooling water pipes will not be in direct contact with the boiler slag. They are mainly used to cool the air inside the slag cooler, thereby increasing the cooling effect of the fluidized bed high-temperature slag by cooling air at a lower temperature. Therefore, there is no risk of water vapor explosion and no safety hazard will be caused to the equipment operation and operators.

[0064] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structure particularly pointed out in the written description and the accompanying drawings.

[0065] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0067] Figure 1 A schematic diagram of the system composition of a circulating fluidized bed boiler slag cooling and conveying system in an embodiment of the present invention;

[0068] Figure 2 It is a schematic diagram of the layout of a circulating fluidized bed boiler slag cooling and conveying system in an embodiment of the present invention;

[0069] Figure 3 It is a schematic diagram of a slag dropping pipe of a circulating fluidized bed boiler slag cooling and conveying system according to an embodiment of the present invention;

[0070] Figure 4 It is a front view of a slag thickness regulating valve of a circulating fluidized bed boiler slag cooling and conveying system according to an embodiment of the present invention;

[0071] Figure 5 A cross-sectional view of a slag thickness regulating valve of a circulating fluidized bed boiler slag cooling and conveying system according to an embodiment of the present invention;

[0072] Figure 6 It is a cross-sectional view of a sub-steel belt slag cooler and a main steel belt slag cooler of a circulating fluidized bed boiler slag cooling and conveying system in an embodiment of the present invention;

[0073] Figure 7 It is a schematic diagram of a tensioning device of a circulating fluidized bed boiler slag cooling and conveying system in an embodiment of the present invention.

[0074] Reference numerals

[0075] 1 is a circulating fluidized bed boiler, 2 is a slag dropping pipe, 21 is a first slag dropping pipe, 22 is a second slag dropping pipe, 23 is a distributor, 24 is an expansion compensator, 25 is a lower pressure transmitter, 26 is an isolation valve, 27 is a thermocouple, 28 is an upper pressure transmitter, 3 is a steel belt slag cooler, 30 is a cooling air inlet valve, 31 is a first sub-steel belt slag cooler, 32 is a second sub-steel belt slag cooler, 33 is a main steel belt slag cooler; 34 is a shell, 341 is an upper cover plate, 342 is a metal heat dissipation fin, 343 is a cooling water pipe, 344 is a spray device for the upper cover plate, 345 is a cooling water pipe for the upper cover plate, 35 is a metal conveyor belt, 351 is a guide roller, 352 is a spray device for the lower part of the conveyor belt, 353 is a sealing brush, 354 is a dustproof plate, 355 is a side air inlet, 36 is a roller, 37 is a slag thickness regulating valve, 371 is a regulating valve body, 372 is a regulating valve drive unit, 373 is Regulating valve plate, 374 is the regulating valve tensioning spring, 38 is the load-bearing circular roller, 39 is the rotating circular roller, 4 is the circulating air duct, 41 is the first dust removal device, 410 is the first dust removal inlet valve, 42 is the second dust removal device, 420 is the third dust removal inlet valve, 421 is the second dust removal inlet valve, 43 is the first fan, 430 is the first fan inlet valve, 431 is the first fan outlet valve, 44 is the second fan, 440 is the second fan inlet valve, 441 is the second fan outlet valve, 45 is the boiler secondary air duct, 5 is the boiler tail flue, 51 is the first tail flue cooling air duct, 511 is the first cooling air duct valve, 52 is the second tail flue cooling air duct, 521 is the second cooling air duct valve, 53 is the third tail flue cooling air duct, 531 is the third cooling air duct valve, 6 is the first tensioning device, and 7 is the second tensioning device. DETAILED DESCRIPTION

[0076] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0077] In response to the problems and shortcomings of the above-mentioned technologies, this patent proposes a special device and system for cooling, conveying and treating closed slag with metal steel belts. The device and system are safe and stable in operation, with extremely low wear and high reliability, and can return most of the slag heat to the boiler, thereby achieving the purpose of fully automated, environmentally friendly and resource-based cooling and conveying of fluidized bed boiler slag.

[0078] In the present invention, the slag produced by the circulating fluidized bed boiler falls onto one or more metal conveyor belts of the closed steel belt slag cooler through one or more slag falling pipes under the action of gravity. The closed steel belt slag cooler 3 is driven by a motor and a reducer. During the slag conveying process on the metal conveyor belt 35, the inhaled ambient cooling air exchanges heat with the slag. The cooled slag is discharged into the downstream main steel belt slag cooler. The heat carried by the cooling air after heat exchange enters the boiler secondary air duct through the fan for recycling. The slag cooling and conveying device has the characteristics of stable operation, energy saving of more than 40%, and low wear and maintenance costs.

[0079] Embodiment 1:

[0080] As attached Figure 1 The schematic diagram of the system composition of a circulating fluidized bed boiler slag cooling and conveying system is shown, which is suitable for cooling, conveying and processing high-temperature slag, including:

[0081] A circulating fluidized bed boiler 1, wherein high-temperature slag is produced inside the circulating fluidized bed boiler 1; a steel belt slag cooler 3, wherein the steel belt slag cooler 3 is connected to the circulating fluidized bed boiler 1 via a slag dropping pipe 2; wherein the steel belt slag cooler 3 is used to cool and transport the high-temperature slag; a circulating air duct 4, wherein the circulating air duct 4 is connected to the tail of the steel belt slag cooler 3, and the outlet of the circulating air duct 4 is connected to the circulating fluidized bed boiler 1; wherein the circulating air duct 4 is used to control the heat exchange between the ambient air and the high-temperature slag, and to reuse the heat of the high-temperature slag; a boiler tail flue 5, wherein the boiler tail flue 5 is also connected to the tail of the steel belt slag cooler 3, and wherein the boiler tail flue 5 is used to introduce the heat of the high-temperature slag into the atmosphere.

[0082] The principle of the present invention is that the slag (high-temperature slag) produced by the circulating fluidized bed boiler 1 enters the first steel strip slag cooler 31 and the second steel strip slag cooler 32 through one or more slag dropping pipes 2 under the action of its own weight. In this process, since the circulating fluidized bed boiler 1 usually works under slightly positive pressure conditions, and the first steel strip slag cooler 31, the second steel strip slag cooler 32 and the main steel strip slag cooler 33 are all operated under slightly negative pressure conditions, during the discharge process of the boiler slag, the slag always fills all the slag dropping pipes 2, thereby ensuring the isolation between the circulating fluidized bed boiler 1 and the first steel strip slag cooler 31 and the second steel strip slag cooler 32 at the bottom. In the present invention: the slag dropping pipe 3 can be used as a channel for the boiler slag to fall, and the slag material column in the slag dropping pipe can be used as a barrier to isolate the circulating fluidized bed boiler 1 from the distributor 23 below, so as to always maintain a constant isolation between the two areas. The interior of the slag dropping pipe 2 is lined with refractory materials or ceramic anti-wear materials. In order to prevent potential safety hazards near the high-temperature drop pipe, the drop pipe 2 is equipped with heat insulation materials or heat dissipation fins and safety protection nets. The circulating air duct 4 of the present invention can absorb the heat of the slag through the ambient air, return the heat to the circulating fluidized bed boiler 1, and cool the slag to a safe temperature. After the ambient air in the circulating air duct 4 absorbs and cools the high-temperature slag of the boiler, if this part of the heat does not need to be recovered to the boiler, it can be discharged along the cooling air duct to the boiler tail flue 5, and discharged to the atmosphere through the boiler dust collector and chimney.

[0083] The beneficial effect of the present invention is that when the high-temperature slag of the circulating fluidized bed boiler 1 is processed, during the process of conveying the high-temperature slag on the metal conveyor belt 35, since there is no relative movement between the high-temperature slag and the metal conveyor belt 35, the wear of the metal conveyor belt 35 is almost negligible, and the service life of the metal conveyor belt 35 is more than 10 years on average, which is about 5 times more than the life of the drum slag cooler. Therefore, the use of the technology of the present invention completely solves the problem of fast and severe wear of traditional technical equipment.

[0084] The boiler slag of the present invention is mainly cooled by cooling air sucked from the environment. Even if cooling water pipes are installed inside the upper cover plate of the slag cooler, these cooling water pipes will not be in direct contact with the boiler slag. They are mainly used to cool the air inside the slag cooler, thereby increasing the cooling effect of the fluidized bed high-temperature slag by cooling air at a lower temperature. Therefore, there is no danger of water vapor explosion, and no safety hazard will be caused to the operation of the equipment and operators. The circulating air duct of the present invention improves the efficiency of the boiler by recycling heat. The slag heat of the present invention can be discharged to the boiler tail flue 5 along the cooling air duct when this part of the heat is not necessary to be recycled to the boiler, and discharged to the atmosphere through the boiler dust collector and chimney.

[0085] Embodiment 2:

[0086] As an embodiment of the present invention: Figure 2 As shown, the circulating air duct 4 includes a first dust removal device 41, a second dust removal device 42, a first fan 43, a second fan 44 and a boiler secondary air duct 45; wherein,

[0087] The inlet end of the first dust removal device 41 is connected to a first dust removal inlet valve 410;

[0088] The inlet end of the second dust removal device 42 is connected to a third dust removal inlet valve 420;

[0089] The inlet ends of the first dust removal device 41 and the second dust removal device 42 are also connected to a second dust removal inlet valve 421;

[0090] The outlet end of the first dust removal device 41 is connected to a first fan inlet valve 430, and the first fan inlet valve 430 is connected to the inlet end of the first fan 43;

[0091] The outlet end of the second dust removal device 42 is connected to a second fan inlet valve 440, and the second fan inlet valve 440 is connected to the inlet end of the second fan 44;

[0092] The air outlet of the first fan 43 is connected to a first fan outlet valve 431;

[0093] The air outlet of the second fan 44 is connected to a second fan outlet valve 441;

[0094] The first fan outlet valve 431 and the second fan outlet valve 441 are both connected to the boiler secondary air duct 45 , and the air outlet of the boiler secondary air duct 45 is connected to the circulating fluidized bed boiler 1 .

[0095] The principle of the present invention is that: a first fan 43 and a second fan 44 are installed in the system of the present invention, both of which are induced draft fans.

[0096] A certain controllable amount of ambient air is sucked in through the cooling air inlet valve (30) and a number of side air inlets 355, and reversely exchanges heat with the boiler slag on the metal conveyor belt 35 under the action of convection to cool the slag. At the same time, the ambient cooling air absorbs heat and is heated, and enters the dust removal device along the first dust removal inlet valve 410, the second dust removal inlet valve 421 and the third dust removal inlet valve 420.

[0097] The first dust removal device 41, the second dust removal device 42, the first fan 43, the second fan 44 and the boiler secondary air duct 45 (or the primary air duct) recover heat to the circulating fluidized bed boiler 1. The first dust removal device 31 and the second dust removal device 42 are the same dust removal devices. The boiler slag and the ambient cooling air complete heat exchange inside the slag cooler, and the temperature of the slag itself is cooled. If the boiler slag reaches a suitable temperature (such as below 120°C) after being cooled by the steel belt slag cooler, then the boiler slag is discharged to the subsequent main steel belt slag cooler 33 and is only a smooth transportation process on it. If the temperature at the outlet of the steel belt slag cooler is still relatively high, the boiler slag can be further cooled in the main steel belt slag cooler (the principle is the same as above) until it is cooled to a suitable safety temperature.

[0098] The beneficial effect of the present invention is that the ambient air sucked in from the cooling air inlet valve exchanges heat with the high-temperature slag of the boiler, and the heat absorbed from the slag is recovered to the circulating fluidized bed boiler 1 along the cooling air duct through the dust removal device, the induced draft fan and the boiler secondary air duct 45 (or the primary air duct), thereby improving the boiler efficiency.

[0099] Embodiment 3:

[0100] As an embodiment of the present invention: Figure 2 As shown, the first steel strip slag cooler 31 passes through the first tail flue cooling air duct 5;

[0101] The circulating air duct 4 includes a flue duct 5 connected to the boiler tail; wherein,

[0102] The first tail flue cooling air duct 51 is provided with a first cooling air duct valve 511;

[0103] The second steel strip slag cooler 32 is connected to the boiler tail flue 5 through the second tail flue cooling air duct 52; wherein,

[0104] The second tail flue cooling air duct 52 is provided with a first cooling air duct valve 521;

[0105] The main steel strip slag cooler 33 is connected to the boiler tail flue 5 through the third cooling air duct 53; wherein,

[0106] The third tail flue cooling air duct 53 is provided with a third cooling air duct valve 531 .

[0107] The principle of the present invention is that after the ambient air sucked in from the cooling air inlet valve passes through the high-temperature slag of the cooling boiler, if this part of the heat does not need to be recovered to the boiler, it can be discharged to the boiler tail flue 5 along the first tail flue cooling air duct 51, the second tail flue cooling air duct 52 and the third tail flue cooling air duct 53 to the cooling air duct, and the cooling air duct valve set in the tail flue cooling air duct controls the entry of cooling air; it is discharged to the atmosphere through the boiler dust collector and chimney. In another embodiment: after the ambient air sucked in from the cooling air inlet valve passes through the high-temperature slag of the cooling boiler, if this part of the heat does not need to be recovered to the boiler, it can also be directly discharged to the atmosphere after passing through the filter provided in the slag bin downstream of the main steel belt slag cooler.

[0108] The beneficial effect of the present invention is that when there is no need to recover the circulating heat through the second method, part of the slag heat is discharged through the cooling air duct of the boiler tail flue 5. In this way, the entire system has the advantages of simpler layout, low cost, and low operation and maintenance cost.

[0109] Embodiment 4:

[0110] As an embodiment of the present invention: Figure 2 and attached Figure 3 As shown, the slag dropping pipe 2 at least includes a first slag dropping pipe 21 and a second slag dropping pipe 22;

[0111] A distributor 23 is provided at the bottom of the first slag dropping pipe 21 and the second slag dropping pipe 22, an expansion compensator 24 is provided on the top of the distributor 23, a lower pressure transmitter 25 is provided on the top of the expansion compensator 24; an isolation valve 26 is provided on the top of the lower pressure transmitter 25, a thermocouple 27 is provided above the isolation valve 26, and an upper pressure transmitter 28 is provided above the thermocouple 27.

[0112] The principle of the present invention is that the slag produced by the circulating fluidized bed boiler is discharged into the lower distributor 23 through one or more slag discharge pipes (slag discharge pipes 2) under the action of its own weight, through the isolation valve 26 and the expansion compensator 24. Since the circulating fluidized bed boiler 1 usually operates under slightly positive pressure conditions, and the steel belt slag cooler operates under slightly negative pressure conditions, the boiler slag is always filled with the slag discharge pipe during the discharge process, thereby ensuring the isolation between the circulating fluidized bed boiler 1 and the lower steel belt slag cooler 3.

[0113] In actual operation, when the slag discharge speed of the steel belt slag cooler 3 is greater than the slag production speed of the fluidized bed boiler 1, and the material level in the slag drop pipe is relatively low, that is, when the differential pressure between the position of the upper pressure transmitter 28 and the position of the lower pressure transmitter 25 is lower than the set safety value, this differential pressure signal will control the running speed of the metal conveyor belt 35 of the steel belt slag cooler through the frequency converter to achieve the best material layer thickness adjustment on the conveyor belt. Therefore, the slag thickness regulating valve 37 installed on the upper part of the steel belt slag cooler can be used as the setting of the maximum slag amount (slag thickness rough adjustment), and the specific thickness of the slag can also be based on the material level meter in the slag drop pipe (a material level meter will also be installed in actual operation) and the upper and lower differential pressure signals, and the speed of the metal conveyor belt can be changed by the frequency converter equipped on the steel belt slag cooler to achieve dynamic automatic adjustment (fine adjustment) of the best material layer. In addition, the distance between the lower end of the distributor 23 and the metal conveyor belt 35 of the downstream steel belt slag cooler should ensure the passage of the maximum boiler slag. The expansion and contraction of the fluidized bed boiler 1 under cold and hot working conditions is absorbed by the expansion compensator 24 installed on the upper part of the distributor 23. When the expansion compensator 24 and downstream equipment need to be repaired and maintained, the isolation valve 26 arranged on the slag dropping pipe can be closed to ensure the safety of operation and maintenance work.

[0114] The beneficial effects of the present invention are as follows: the slag dropping pipe 2 of the present invention can be used as a channel for the boiler slag to drop, and the slag material column in the slag dropping pipe 2 can be used as a barrier to isolate the fluidized bed boiler 1 from the distributor 23 below, so as to always maintain a constant isolation between the two areas; and in the present invention, when the slag discharge speed is greater than the slag production speed of the circulating fluidized bed boiler 1 and the material level in the slag dropping pipe 2 is relatively low, that is, when the differential pressure between the position of the upper pressure transmitter 28 and the position of the lower pressure transmitter 25 is lower than the set safety value, this differential pressure signal can control the running speed of the metal conveyor belt 35 of the steel belt cooler through the frequency converter, thereby realizing the optimal material layer thickness adjustment on the conveyor belt.

[0115] Embodiment 5:

[0116] As an embodiment of the present invention: the interior of the slag dropping pipe 2 is lined with refractory materials or ceramic anti-wear materials, and the exterior is installed with heat insulation materials, heat dissipation fins and a safety protection net.

[0117] The beneficial effects of the present invention are as follows: the refractory material or ceramic anti-wear material can increase the service life of the slag falling pipe. The heat insulation material prevents high temperature from affecting the working state and efficiency of other parts. The heat dissipation fins can quickly dissipate the heat dissipated from the slag falling pipe, and the safety protection net can prevent the slag falling pipe from being damaged by external accidents and can also prevent the slag falling pipe from being accidentally touched.

[0118] Embodiment 6:

[0119] As an embodiment of the present invention: Figure 2 , Attachment Figure 3 , Attachment Figure 6 As shown, the first steel strip slag cooler 31, the second steel strip slag cooler 32 and the main steel strip slag cooler 33 are all composed of a shell 34, a metal conveyor belt 35 and a roller 36; wherein,

[0120] An upper cover plate 341 is provided on the upper portion of the housing 34;

[0121] The metal conveyor belt 35 and the roller 36 are arranged inside the shell 34, and the metal conveyor belt 35 is sleeved outside the roller 36; wherein,

[0122] There are at least two rollers 36;

[0123] The metal conveyor belt 35 of the first steel strip slag cooler 31 and the second steel strip slag cooler 32 is also provided with a slag thickness regulating valve 37;

[0124] The slag thickness regulating valve 37 includes a regulating valve body 371, a regulating valve driving unit 372, a regulating valve plate 373 and a regulating valve tensioning spring 374; wherein,

[0125] The regulating valve driving unit 372 is arranged on the top of the regulating valve body 371, the regulating valve plate 373 and the regulating valve tensioning spring 374 are arranged inside the regulating valve body 371, and the two ends of the regulating valve tensioning spring 374 are connected to the upper and lower ends of the regulating valve plate 373;

[0126] The lower part of the metal conveyor belt 35 in the working direction is supported by a plurality of round supporting rollers 38 along the entire width of the conveyor belt;

[0127] The two sides of the lower part of the metal conveyor belt 35 in the return direction are supported by rotary round rollers 39;

[0128] Guide rollers 351 are designed and installed on both sides of the metal conveyor belt 35 in the working direction and the return direction;

[0129] The lower part of the metal conveyor belt 35 is provided with a conveyor belt lower spray system 352. On the return side of the metal conveyor belt 35, the metal conveyor belt 35 can be sprayed and cooled by the metal conveyor belt lower spray device 352, thereby reducing the temperature of the metal conveyor belt 35, so that it can take away more heat during the contact and conduction process with the fluidized bed high-temperature slag. In the process of the above-mentioned lower spray device, the boiler high-temperature slag and the metal conveyor belt 35 transfer heat to the spray water mist, which evaporates quickly, and there will be no water condensation problem at the outlet of the main steel belt slag cooler.

[0130] The principle of the present invention is that during the transportation of the high-temperature slag of the fluidized bed on the metal conveyor belt 35, the lower part of the metal conveyor belt 35 in the working direction is supported by a plurality of load-bearing circular rollers 38 along the entire width of the conveyor belt. The metal conveyor belt 35 rolls on the load-bearing circular rollers 38, and the friction between the two is very small, which ensures that the metal conveyor belt 35 has a very long service life. The two sides of the lower part of the metal conveyor belt 35 in the return direction are supported by rotating circular rollers 39, and guide rollers 351 are designed and installed on both sides of the working direction and the return direction of the metal conveyor belt 35 to monitor and prevent the metal conveyor belt 35 from running off.

[0131] The upper cover plate 341 of the slag cooler is internally installed with cooling water pipes to increase the cooling effect of the high-temperature slag in the fluidized bed. The slag thickness regulating valve 37 is installed downstream of the distributor 23. In the present invention, the material layer thickness at the maximum slag discharge is calculated based on the maximum slag discharge designed for the circulating fluidized bed boiler and the effective width of the metal conveyor belt 35, combined with the normal operating speed of the metal conveyor belt 35. The slag material layer thickness can be preliminarily set by adjusting the distance between the regulating valve plate 373 and the lower metal conveyor belt 35.

[0132] The beneficial effect of the present invention is that the slag discharged by the distributor 23 can be evenly spread over the width direction of the entire metal conveyor belt 35 after passing through the regulating valve plate 373, thereby increasing the heat exchange area of ​​the slag material layer with the upper and lower parts, heat radiation and heat conduction, and greatly improving the heat exchange effect. The slag thickness regulating valve 37 can not only adjust the thickness of the slag material layer, but also has the function of spreading the slag material layer. When large-sized slag cannot pass through the space between the regulating valve and the metal conveyor belt, under the driving force of the running metal conveyor belt, the large-sized slag will overcome the tensioning force of the regulating valve tensioning spring 374 to push the regulating valve plate 373 to rotate in the running direction of the metal conveyor belt 35, thereby ensuring the passage of the large-sized slag, and then under the force of the tensioning spring 374, the regulating valve plate 373 returns to its original position. The slag thickness regulating valve drive unit 372 can be designed as manual, pneumatic, electric or other driving methods as needed.

[0133] Embodiment 7:

[0134] As an embodiment of the present invention: Figure 3 , Attachment Figure 6 The upper cover plate 341 and both sides of the first steel strip slag cooler 31, the second steel strip slag cooler 32 and the main steel strip slag cooler 33 are provided with metal heat dissipation fins 342, and the interior of the upper cover plate 341 is provided with cooling water pipes 343;

[0135] An upper cover spray device 344 is provided in the middle of the upper cover 341 ; the upper cover spray device 344 is located directly above the metal conveyor belt 35 , and the upper cover spray device 344 is supplied with water by a cooling water pipe 343 .

[0136] The principle and beneficial effect of the present invention are: in order to increase the cooling effect of boiler slag in the steel belt slag cooler and the main steel belt slag cooler, metal heat dissipation fins 342 are installed on the upper cover plate 341 and both sides of the slag cooler, and an upper cover plate spray device 344 is installed directly above the metal conveyor belt 35. When the amount of boiler slag is large and the slag layer is thick, the slag at the bottom of the metal conveyor belt is difficult to be cooled. At this time, starting the above-mentioned upper cover plate spray device 344 can effectively reduce the slag temperature. The boiler slag of the present invention is mainly cooled by cooling air sucked from the environment, and there is basically no water consumption. Even if the water spray device is started in the case of large-capacity slag, since the water is atomized, it is all evaporated by hot air and there is no water condensation, so the water consumption is very small and almost negligible.

[0137] Embodiment 8:

[0138] As an embodiment of the present invention: Figure 6 The first steel strip slag cooler 31, the second steel strip slag cooler 32 and the main steel strip slag cooler 33 are further provided with sealing brushes 353; a gap is provided between the bottom and side of the sealing brush 353 and the metal conveyor belt 435; the sealing brush 353 is made of high temperature resistant metal or non-metal;

[0139] A dustproof plate 354 is installed between the working layer and the return layer of the metal conveyor belt 35.

[0140] The side of the steel strip slag cooler 3 is also provided with a side air inlet 355 .

[0141] The principle and beneficial effect of the present invention are as follows: a sealing brush 353 (the sealing brush material can be high temperature resistant metal or non-metal) is installed at the lower part of the internal guide plate of the sub-strip slag cooler and the main steel belt slag cooler 33, and the bottom and side of the sealing brush 353 maintain a certain appropriate gap with the metal conveyor belt 35 to prevent finer slag particles from falling to the bottom of the slag cooler. A dustproof plate 354 is installed between the working layer and the return of the metal conveyor belt 35 to prevent the ultra-fine slag particles diffused inside the slag cooler from falling into the return metal conveyor belt. At the same time, a fine material cleaning device can also be designed and installed at the bottom of the sub-strip slag cooler and the main steel belt slag cooler. This cleaning device can be a chain scraper structure or a self-cleaning scraper connected to the metal conveyor belt itself.

[0142] Embodiment 9:

[0143] As an embodiment of the present invention: Figure 7The first steel strip slag cooler 31, the second steel strip slag cooler 32 and the main steel strip slag cooler 33 are provided with a first tensioning device 6 and a second tensioning device 7 at their tails;

[0144] The first tensioning device 6 is a pneumatic tensioning device or a hydraulic tensioning device;

[0145] The second tensioning device 7 is a mechanical tensioning device.

[0146] The principle of the present invention is that during the process of conveying boiler slag on the upper part of the metal conveyor belt 35, it absorbs the heat in the slag under the action of heat conduction, and its own temperature rises and expands, causing the length of the entire metal conveyor belt 35 to become longer. The pneumatic or hydraulic tensioning device or mechanical tensioning device installed at the tail of the steel belt slag cooler pushes the tail roller in the roller 36 to continue to tension the entire metal conveyor belt 35, thereby absorbing these thermal expansions. Similarly, when the temperature of the metal conveyor belt decreases, the above-mentioned tensioning device pushes the tail roller in the opposite direction to absorb the contraction of the metal conveyor belt. In this way, the entire metal conveyor belt 35 always maintains a constant set tension.

[0147] Embodiment 10:

[0148] As an embodiment of the present invention: the system realizes cooling, conveying and processing of high-temperature slag through the following steps:

[0149] Step 1: The high-temperature slag inside the circulating fluidized bed boiler 1 enters the slag falling pipe 2 under the action of its own gravity;

[0150] Step 2: the expansion compensator 24 of the slag falling pipe 2 performs contraction or expansion compensation on the slag falling pipe 2 according to the cold condition and hot condition of the circulating fluidized bed boiler 1;

[0151] Step 3: After the slag dropping pipe 2 is compensated for shrinkage or expansion, the high-temperature slag falls into the metal conveyor belt 35 of the steel belt slag cooler through the distributor 23;

[0152] Step 4: When the high-temperature slag falls onto the metal conveyor belt 35, the slag thickness regulating valve 37 calculates the material layer thickness at the maximum slag discharge amount according to the designed maximum slag discharge amount of the circulating fluidized bed boiler 1 and the effective width of the metal conveyor belt 35, combined with the normal operating speed of the metal conveyor belt 35, and sets the slag material layer thickness by adjusting the distance between the regulating valve plate 373 and the lower metal conveyor belt 35;

[0153] Step 5: Control the upper cover spray device 344 and the lower conveyor belt spray device 352 to spray and cool the metal conveyor belt 35 according to the thickness of the slag layer;

[0154] Step 6: When the heat generated after cooling the high-temperature slag and the metal conveyor belt 35 in step 5 needs to be reused through the circulating air duct 4, step 7 is executed; when the heat generated after cooling the high-temperature slag and the metal conveyor belt 35 in step 5 does not need to be recovered and needs to be introduced into the atmosphere through the boiler tail flue 5, step 8 is executed;

[0155] Step 7: The first induced draft fan 43 or the first induced draft fan 44 introduces ambient air through the side air inlet 355. The ambient air carries the heat in the steel strip slag cooler and passes through the first dust removal device 41 or the second dust removal device 42 for dust removal. The ambient air is then introduced into the boiler secondary air duct 45 through the first induced draft fan 43 or the second induced draft fan 44 and enters the circulating fluidized bed boiler 1 until the high-temperature slag is cooled to a suitable safety temperature.

[0156] Step 8: The first induced draft fan 43 or the first induced draft fan 44 introduces ambient air through the side air inlet 355, and the ambient air carries the heat in the steel strip slag cooler and is discharged to the boiler tail flue 5 along the cooling air duct to the tail flue, and is discharged to the atmosphere through the boiler dust collector and the chimney.

[0157] The principle and beneficial effect of the present invention are as follows: during the transportation of the high-temperature slag of the fluidized bed on the metal conveyor belt 35, since there is no relative movement between the slag and the metal conveyor belt, the wear of the metal conveyor belt can be almost ignored, and the service life of the metal conveyor belt is more than 10 years on average, which is about 5 times more than the service life of the roller slag cooler. Therefore, the use of the technology of the present invention completely solves the problem of fast wear and serious wear of the traditional technical equipment. The boiler slag is mainly cooled by the cooling air sucked from the environment. Even if the cooling water pipe is installed inside the upper cover plate of the slag cooler, these cooling water pipes will not directly contact the boiler slag. They are mainly used to cool the air inside the slag cooler, thereby increasing the cooling effect of the high-temperature slag of the fluidized bed by cooling air at a lower temperature. Therefore, there is no danger of water vapor explosion, and no safety hazard will be caused to the operation of the equipment and the operating personnel; the ambient air sucked by the cooling air exchanges heat with the high-temperature slag of the boiler, and a large amount of heat energy absorbed from the slag is recovered to the circulating fluidized bed boiler along the cooling air duct through the dust removal device, the induced draft fan and the boiler secondary air duct (or primary air duct), thereby improving the boiler efficiency. Boiler slag is mainly cooled by cooling air sucked from the environment, with basically no water consumption. Even when the water spray device is started in the case of large-capacity slag, since the water is atomized, it is all evaporated by the hot air without water condensation, so the water consumption is very small and almost negligible.

[0158] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A circulating fluidized bed boiler slag cooling and conveying system, characterized in that: Suitable for cooling, conveying and handling of high-temperature slag, including: A circulating fluidized bed boiler (1), wherein high-temperature slag is generated inside the circulating fluidized bed boiler (1); A steel belt slag cooler (3), the steel belt slag cooler (3) being connected to the circulating fluidized bed boiler (1) via a slag dropping pipe (2); the steel belt slag cooler (3) is used to cool and transport the high-temperature slag; A circulating air duct (4), the circulating air duct (4) being connected to the rear of the steel strip slag cooler (3), and the outlet of the circulating air duct (4) being connected to the circulating fluidized bed boiler (1); the circulating air duct (4) is used to control the heat exchange between the ambient air and the high-temperature slag, so as to recycle the heat of the high-temperature slag; A boiler tail flue (5), the boiler tail flue (5) being connected to the tail of the steel strip slag cooler (3), and the boiler tail flue (5) being used to discharge cooling air after heat exchange with the high-temperature slag to the atmosphere through a dust collector; The steel strip slag cooler (3) comprises a sub-steel strip slag cooler and a main steel strip slag cooler (33); The steel strip slag cooler comprises at least a first steel strip slag cooler (31) and a second steel strip slag cooler (32); The first steel strip slag cooler (31) is connected to the boiler tail flue (5) via a first tail flue cooling air duct (51); wherein: The first tail flue cooling air duct (51) is provided with a first cooling air duct valve (511); The second steel strip slag cooler (32) is connected to the boiler tail flue (5) via a second tail flue cooling air duct (52); wherein: The second tail flue cooling air duct (52) is provided with a second cooling air duct valve (521); The main steel belt slag cooler (33) is connected to the boiler tail flue (5) via a third tail flue cooling air duct (53); wherein, The third tail flue cooling air duct (53) is provided with a third cooling air duct valve (531).

2. A circulating fluidized bed boiler slag cooling and conveying system according to claim 1, characterized in that: The circulating air duct (4) comprises a first dust removal device (41), a second dust removal device (42), a first fan (43), a second fan (44) and a boiler secondary air duct (45); wherein: The inlet end of the first dust removal device (41) is connected to a first dust removal inlet valve (410); The inlet end of the second dust removal device (42) is connected to a third dust removal inlet valve (420); The inlet ends of the first dust removal device (41) and the second dust removal device (42) are also connected to a second dust removal inlet valve (421); The outlet end of the first dust removal device (41) is connected to a first fan inlet valve (430), and the first fan inlet valve (430) is connected to the inlet end of the first fan (43); The outlet end of the second dust removal device (42) is connected to a second fan inlet valve (440), and the second fan inlet valve (440) is connected to the inlet end of the second fan (44); The air outlet of the first fan (43) is connected to a first fan outlet valve (431); The air outlet of the second fan (44) is connected to a second fan outlet valve (441); The first fan outlet valve (431) and the second fan outlet valve (441) are both connected to the boiler secondary air duct (45), and the air outlet of the boiler secondary air duct (45) is connected to the circulating fluidized bed boiler (1).

3. The circulating fluidized bed boiler slag cooling and conveying system according to claim 1, characterized in that: The slag dropping pipe (2) comprises at least a first slag dropping pipe (21) and a second slag dropping pipe (22); A distributor (23) is provided at the bottom of the first slag dropping pipe (21) and the second slag dropping pipe (22); an expansion compensator (24) is provided on the top of the distributor (23); a lower pressure transmitter (25) is provided on the top of the expansion compensator (24); an isolation valve (26) is provided on the top of the lower pressure transmitter (25); a thermocouple (27) is provided above the isolation valve (26); and an upper pressure transmitter (28) is provided above the thermocouple (27).

4. The circulating fluidized bed boiler slag cooling and conveying system according to claim 1, characterized in that: The interior of the slag dropping pipe (2) is lined with refractory material or ceramic anti-wear material, and the exterior is installed with heat insulation material, heat dissipation fins and a safety protection net.

5. The circulating fluidized bed boiler slag cooling and conveying system according to claim 1, characterized in that: The first steel strip slag cooler (31), the second steel strip slag cooler (32) and the main steel strip slag cooler (33) are all composed of a shell (34), a metal conveyor belt (35) and a roller (36); wherein: An upper cover plate (341) is provided on the upper portion of the housing (34); The metal conveyor belt (35) and the roller (36) are arranged inside the shell (34), and the metal conveyor belt (35) is sleeved outside the roller (36); wherein, There are at least two rollers (36); The metal conveyor belts (35) of the first steel strip slag cooler (31) and the second steel strip slag cooler (32) are also provided with slag thickness regulating valves (37); The slag thickness regulating valve (37) comprises a regulating valve body (371), a regulating valve driving unit (372), a regulating valve plate (373) and a regulating valve tensioning spring (374); wherein, The regulating valve driving unit (372) is arranged on the top of the regulating valve body (371), the regulating valve plate (373) and the regulating valve tensioning spring (374) are arranged inside the regulating valve body (371), and the two ends of the regulating valve tensioning spring (374) are connected to the upper and lower ends of the regulating valve plate (373); The lower part of the metal conveyor belt (35) in the working direction is supported by a plurality of round supporting rollers (38) along the entire width of the conveyor belt; Both sides of the lower part of the metal conveyor belt (35) in the return direction are supported by rotary round rollers (39); Guide rollers (351) are designed and installed on both sides of the metal conveyor belt (35) in the working direction and the return direction; A conveyor belt lower spraying device (352) is provided at the lower part of the metal conveyor belt (35).

6. The circulating fluidized bed boiler slag cooling and conveying system according to claim 1, characterized in that: The upper cover plate (341) and both sides of the first steel strip slag cooler (31), the second steel strip slag cooler (32) and the main steel strip slag cooler (33) are installed with metal heat dissipation fins (342), and the upper cover plate (341) is installed with an upper cover plate cooling water pipe (345) inside; An upper cover spray device (344) is provided in the middle of the upper cover (341); the upper cover spray device (344) is located directly above the metal conveyor belt (35), and the upper cover spray device (344) is supplied with water by a cooling water pipe (343).

7. The circulating fluidized bed boiler slag cooling and conveying system according to claim 1, characterized in that: The first steel strip slag cooler (31), the second steel strip slag cooler (32) and the main steel strip slag cooler (33) are also provided with sealing brushes (353); gaps are provided between the bottom and side of the sealing brushes (353) and the metal conveyor belt (35); the sealing brushes (353) are made of high temperature resistant metal or non-metal; A dustproof plate (354) is installed between the working layer and the return layer of the metal conveyor belt (35); The side of the steel strip slag cooler (3) is also provided with a side air inlet (355).

8. The circulating fluidized bed boiler slag cooling and conveying system according to claim 1, characterized in that: The tails of the first steel strip slag cooler (31), the second steel strip slag cooler (32) and the main steel strip slag cooler (33) are provided with a first tensioning device (6) and a second tensioning device (7); wherein: The first tensioning device (6) is a starting tensioning device or a hydraulic tensioning device; The second tensioning device (7) is a mechanical tensioning device.

9. A circulating fluidized bed boiler slag cooling and conveying system according to any one of claims 1 to 8, characterized in that: The system realizes the cooling, transportation and treatment of high-temperature slag through the following steps: Step 1: The high-temperature slag inside the circulating fluidized bed boiler (1) enters the slag drop pipe (2) under the action of its own gravity; Step 2: the expansion compensator (24) of the slag dropping pipe (2) performs contraction or expansion compensation on the slag dropping pipe (2) according to the cold condition and hot condition of the circulating fluidized bed boiler (1); Step 3: After the slag dropping pipe (2) is compensated for shrinkage or expansion, the high-temperature slag falls into the metal conveyor belt (35) of the steel belt slag cooler through the distributor (23); Step 4: When the high-temperature slag falls onto the metal conveyor belt (35), the slag thickness regulating valve (37) calculates the material layer thickness at the maximum slag discharge amount according to the designed maximum slag discharge amount of the circulating fluidized bed boiler (1) and the effective width of the metal conveyor belt (35), combined with the normal operating speed of the metal conveyor belt (35), and sets the slag material layer thickness by adjusting the distance between the regulating valve plate (373) and the lower metal conveyor belt (35); Step 5: controlling the upper cover spraying device (344) and the lower conveyor belt spraying device (352) to atomize and spray cool the metal conveyor belt (35) according to the thickness of the slag layer; Step 6: When the heat generated after cooling the high-temperature slag and the metal conveyor belt (35) in step 5 needs to be reused through the circulating air duct (4), step 7 is executed; when the heat generated after cooling the high-temperature slag and the metal conveyor belt (35) in step 5 does not need to be recovered and needs to be introduced into the atmosphere through the boiler tail flue (5), step 8 is executed; Step 7: The first induced draft fan (43) or the second induced draft fan (44) introduces ambient air through the side air inlet (355), and the ambient air carries the heat in the steel strip slag cooler, passes through the first dust removal device (41) and the second dust removal device (42) for dust removal, and is then introduced into the boiler secondary air duct (45) through the first induced draft fan (43) or the first induced draft fan (44), and enters the circulating fluidized bed boiler (1) until the high-temperature slag is cooled to a suitable safety temperature; Step 8: The first induced draft fan (43) or the second induced draft fan (44) introduces ambient air through the side air inlet (355), and the ambient air carries the heat in the steel strip slag cooler and is discharged along the tail flue cooling air duct to the boiler tail flue (5), and is discharged to the atmosphere through the boiler dust collector and chimney.

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