CN111536507A - Low-emission type circulating fluidized bed boiler separation return regulation and control system and integration method - Google Patents

Abstract

The low-emission circulating fluidized bed boiler separation material returning regulation and control system comprises a hearth, a separator, a material returning device, a slag discharge pipe, a slag discharge regulating valve, a slag cooler, an ash discharge pipe, an ash discharge regulating valve, an ash cooling slag machine, an ash discharge pipe, an ash discharge regulating valve, an ash cooling machine and an ash removing machine; the inlet end of the ash discharge pipe extends into the air chamber and is communicated with the bottom of the material return valve, and the position of the movable cylinder is adjustable in the fixed cylinder; the integration method comprises the steps of fuel combustion, flue gas and ash separation and ash residue discharge under the condition of boiler load reduction or fuel heat value reduction. The invention controls the amount of separated and returned ash, ash and slag discharge, or the separated and returned ash amountAnd ash and clinker discharging and ash discharging methods, so that the ash separating amount, the ash returning amount and hearth bed material of the boiler can be adjusted when the boiler is under low load or the fuel suddenly changes, the temperature field in the hearth is reasonable and uniform, the boiler can safely, stably and efficiently run for a long time, and NO is used_XAnd SO₂And (4) ultralow pollutant emission.

Description

Low-emission circulating fluidized bed boiler separation and return control system and integration method

technical field

The invention relates to a boiler separation and return material control system and an integration method, in particular to a low-emission circulating fluidized bed boiler separation and return material control system and an integration method.

Background technique

The circulating fluidized bed boiler is an environmentally friendly and energy-saving combustion technology. With the application of the low-emission circulating fluidized bed boiler with high-efficiency separators and self-balancing return devices, the optimization of the combustion system and the reconfiguration of the fluid state have achieved good results. However, fuel replacement and load mutation will affect the safe and stable operation of boilers, energy-saving combustion and environmental protection emissions. Due to the improved separation efficiency of the boiler and the increase of fine ash in the circulating material, the bed quality is improved, the bed inventory is reduced, the combustion efficiency is improved, and low-nitrogen combustion is realized. However, there is a problem of too much fine ash in the circulating material under low load operation of the boiler or when the calorific value of the fuel is reduced, resulting in too low bed temperature in the lower part of the furnace, unstable combustion and flameout, incomplete combustion of fuel and reduction of desulfurization efficiency in the furnace, etc. , which is not conducive to the stable operation of the boiler, efficient combustion and ultra-low emission of pollutants.

SUMMARY OF THE INVENTION

The present invention solves the problems of excessive circulating material amount, unstable combustion and flameout, reduced desulfurization efficiency in the furnace, low boiler combustion efficiency and high pollutant discharge when the load of the existing low-emission circulating fluidized bed boiler decreases or the fuel calorific value decreases. , and further provide a low-emission circulating fluidized bed boiler separation and return material control system and integration method.

The technical scheme of the present invention is as follows: a low-emission circulating fluidized bed boiler separation and return material control system includes a furnace, a separator and a return material; the separation and return material control system further includes a slag discharge pipe, a slag discharge control valve, and a slag-cooling control valve. machine, ash discharge pipe, ash discharge control valve, cold ash machine, ash discharge pipe, ash discharge control valve, cold ash machine and ash removal machine;

The vertical material pipe of the returner is installed on the upper part of the return valve of the returner, the return leg of the returner is installed on the side of the return valve, and the air cap of the returner is installed on the back of the return valve. At the bottom, the air chamber of the returner is installed at the lower part of the return valve, the inlet end of the ash discharge pipe extends into the air chamber and communicates with the bottom of the return valve, and the outlet end of the ash discharge pipe is connected to the cold ash The ash discharge regulating valve is installed on the ash discharge pipe, the ash cooler is connected with the ash and slag removal machine, the material return leg is communicated with the rear lower part of the furnace, and the upper edge of the vertical material pipe of the return material A plurality of observation holes are arranged vertically, and a limestone desulfurization interface is arranged on the return leg;

The central cylinder of the separator includes a fixed cylinder and a movable cylinder. The fixed cylinder is installed on the top of the vertical section of the separator. The fixed cylinder is connected to the tail flue. The wall of the movable cylinder is provided with a plurality of groups of through holes along the length direction. A set of through holes is opened through, the movable cylinder is fixed in the fixed cylinder by a pin shaft passing through a set of through holes and any set of through holes to realize position adjustment, and the sides of the inlet and outlet speed regulating sections are evenly arranged There are multiple SNCR denitration interfaces, the inlet and outlet speed control sections of the separator are installed on the side of the vertical section of the separator, the cone section of the separator is installed at the lower part of the vertical section, and the inlet and outlet speed control sections are behind the upper part of the furnace. The outlet is connected, and the cone section is connected with the vertical material pipe;

The bottom of the furnace is respectively equipped with a slag discharge pipe and an ash discharge slag pipe at both ends of the length direction. The slag discharge control valve is installed on the slag discharge pipe. On the slag pipe, the ash discharge slag pipe is connected with the cold ash slag machine, and the cold slag machine and the cold ash slag machine are respectively connected with the ash removal machine.

The integrated method one of the low-emission circulating fluidized bed boiler separation and return material control system of the present invention includes the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The ash discharge regulating valve on the ash discharge pipe is closed, and the fuel enters the lower part of the furnace through the feeding device, and is heated by the fluidized high-temperature bed material and burns rapidly. The fine ash enters the inlet and outlet speed regulation section of the separator from the rear outlet of the upper part of the furnace, and then enters the vertical section of the separator to separate the flue gas and fine ash around the central tube;

Change the length of the movable cylinder of the central cylinder, adjust the separation of flue gas and fine ash, reduce or increase the amount of separated ash, so that the returned ash returned to the furnace 1 can stabilize the temperature in the furnace between 800-900 °C, and the separated separation The ash enters the returner through the cone of the separator, and the separated ash enters the return valve through the vertical material leg of the return material. Continuous fluidized circulation combustion, the separated flue gas enters the tail flue through the central tube for heat exchange and then is discharged out of the furnace;

2. Ash discharge

Close the ash discharge control valve installed on the ash discharge slag pipe at the position of the corresponding return leg, adjust the opening of the slag discharge control valve on the slag discharge pipe, and remove the large particle slag formed by the combustion of fuel in the lower part of the furnace, high temperature large particles The slag is cooled by the slag cooler and then discharged to the ash remover and transported to the slag bin.

The integrated method 2 of the low-emission circulating fluidized bed boiler separation and return material control system of the present invention comprises the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The ash discharge regulating valve on the ash discharge pipe is closed, and the fuel enters the lower part of the furnace through the feeding device, and is heated by the fluidized high-temperature bed material and burns rapidly. The fine ash enters the inlet and outlet speed regulation section of the separator from the rear outlet of the upper part of the furnace, and then enters the vertical section of the separator to separate the flue gas and fine ash around the central tube;

The separated separated ash enters the returner through the cone of the separator, the separated ash enters the return valve through the vertical material leg of the return material, and part of the returned material returns to the lower part of the furnace through the return leg, and enters the furnace through the feeding device The fuel at the bottom is continuously fluidized and cyclically burned, and the separated flue gas enters the tail flue through the central tube for heat exchange and then is discharged out of the furnace;

2. Ash discharge

Adjust the opening of the slag discharge control valve on the slag discharge pipe to remove the large particle slag formed by the combustion of fuel in the lower part of the furnace, and improve the quality of the formed bed material. To the slag bin; adjust the opening of the ash discharge and slag control valve installed on the ash discharge slag pipe at the position of the corresponding return leg to remove most of the returned ash and a small amount of slag, reduce the stock of the formed bed material, and stabilize the furnace chamber. The temperature is between 800-900 ℃, and the high temperature ash is cooled by the cold ash machine and then discharged to the ash removal machine and transported to the slag bin.

The third integrated method of the low-emission circulating fluidized bed boiler separation and return material control system of the present invention includes the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The fuel enters the lower part of the furnace through the feeding device, and is heated by the fluidized high-temperature bed material and burns rapidly. A large amount of materials generated during the combustion process are carried to the upper part of the furnace by the flue gas, and the fine ash is carried by the flue gas and enters the separator from the rear outlet of the upper part of the furnace. Import and export speed regulation section, and then enter the vertical section of the separator to separate the flue gas and fine ash around the central tube;

The separated separated ash enters the returner through the cone of the separator, the separated ash enters the return valve through the vertical material leg of the return material, and part of the returned material returns to the lower part of the furnace through the return leg, and enters the furnace through the feeding device The fuel at the bottom is continuously fluidized and cyclically burned. The separated flue gas enters the tail flue through the central tube for heat exchange and is discharged out of the furnace. The opening of the ash discharge regulating valve on the ash discharge pipe is adjusted to remove part of the returned ash. Control the amount of ash returned to the furnace, and stabilize the temperature in the furnace between 800-900 °C;

2. Ash discharge

Close the ash discharge control valve installed on the ash discharge slag pipe at the position of the corresponding return leg, adjust the opening of the slag discharge control valve on the slag discharge pipe, and remove the large particle slag formed by the combustion of fuel in the lower part of the furnace, high temperature large particles The slag is cooled by the slag cooler and then discharged to the slag remover and transported to the slag bin. The high temperature ash is cooled by the ash cooler and then discharged to the slag remover and transported to the slag bin.

The low-emission circulating fluidized bed boiler separation and returning material control system and integration method 4 of the present invention comprises the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The ash discharge regulating valve on the ash discharge pipe is closed, and the fuel enters the lower part of the furnace through the feeding device, and is heated by the fluidized high-temperature bed material and burns rapidly. The fine ash enters the inlet and outlet speed regulation section of the separator from the rear outlet of the upper part of the furnace, and then enters the vertical section of the separator to separate the flue gas and fine ash around the central tube;

Change the length of the movable cylinder of the central cylinder, adjust the separation of flue gas and fine ash, reduce or increase the amount of separated ash, so that the returned ash returned to the furnace can stabilize the temperature in the furnace between 800-900 °C, and the separated ash can be separated. The cone of the separator enters the returner, and the separated ash enters the return valve through the vertical leg of the returner. Part of the returned ash returns to the lower part of the furnace through the return leg, and the fuel that enters the bottom of the furnace through the feeding device is heated for a continuous period of time. Fluidized cyclic combustion, the separated flue gas enters the tail flue through the central tube for heat exchange and then is discharged out of the furnace;

2. Ash discharge

Adjust the opening of the slag discharge control valve on the slag discharge pipe to remove the large particle slag formed by the combustion of fuel in the lower part of the furnace, and improve the quality of the formed bed material. to the slag bin;

Adjust the opening of the ash discharge and slag control valve installed on the ash discharge and slag pipe at the position of the corresponding return leg to remove most of the returned ash and a small amount of slag, reduce the stock of the formed bed material, and stabilize the temperature in the furnace at 800- Between 900 ℃, the high temperature ash and slag are cooled by the cold ash slag machine and then discharged to the slag remover, and then transported to the slag bin.

The fifth integrated method of the low-emission circulating fluidized bed boiler separation and return material control system of the present invention includes the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The fuel enters the lower part of the furnace through the feeding device, and is heated by the fluidized high-temperature bed material and burns rapidly. A large amount of materials generated during the combustion process are carried to the upper part of the furnace by the flue gas, and the fine ash is carried by the flue gas and enters the separator from the rear outlet of the upper part of the furnace. Import and export speed regulation section, and then enter the vertical section of the separator to separate the flue gas and fine ash around the central tube;

The separated separated ash enters the returner through the cone of the separator, the separated ash enters the return valve through the vertical material leg of the return material, and part of the returned material returns to the lower part of the furnace through the return leg, and enters the furnace through the feeding device The fuel at the bottom is continuously fluidized and cyclically burned. The separated flue gas enters the tail flue through the central tube for heat exchange and is discharged out of the furnace. The opening of the ash discharge regulating valve on the ash discharge pipe is adjusted to remove part of the returned ash. Control the amount of ash returned to the furnace, and stabilize the temperature in the furnace between 800-900 °C;

2. Ash discharge

Adjust the opening of the slag discharge control valve on the slag discharge pipe to remove the large particle slag formed by the combustion of fuel in the lower part of the furnace, and improve the quality of the formed bed material. to the slag bin;

Adjust the opening of the ash discharge and slag control valve installed on the ash discharge and slag pipe at the position of the corresponding return leg to remove most of the returned ash and a small amount of slag, reduce the stock of the formed bed material, and stabilize the temperature in the furnace at 800- Between 900°C, the high-temperature ash is cooled by the ash cooler and then discharged to the ash remover and transported to the slag bin.

In the above scheme, the limestone desulfurization in the furnace is realized by feeding limestone after the limestone desulfurization interfaces 3-7 on the returner 3 are integrated; SNCR is low-cost denitrification, actively controls the formation of NO _X and the removal of NO _X and SO ₂ in the furnace, and realizes ultra-low emission of NO _X and SO ₂ pollutants.

Compared with the prior art, the present invention has the following beneficial effects:

1. The adjustable center cylinder designed by the present invention increases or decreases the total length of the center cylinder to achieve flexible adjustment of the total length of the center cylinder, so as to adjust the efficiency of the separator and control the amount of separated ash, so that when the boiler is at low load or when the fuel suddenly changes, To ensure the separation of ash, to ensure the stable operation of the boiler.

2. The ash discharge pipe and the ash discharge regulating valve are designed in the present invention. By controlling the amount of ash returned, the amount of ash returned can be controlled when the boiler is under low load or when the fuel suddenly changes, so that the temperature in the furnace can reach the design value, which can be controlled at 800- Within the temperature range of 900°C, avoid the furnace shutdown caused by unstable combustion, flameout or coking, environmental protection emissions that are not up to standard caused by low desulfurization efficiency in the furnace, and boiler efficiency caused by incomplete combustion of fuel, etc., so that the boiler can operate safely, stably and efficiently for a long time. Ultra-low emissions of NO _X and SO ₂ . It has good social and economic benefits.

3. The separation and return material control system of the present invention adopts a high-efficiency separator to realize adjustable separation efficiency, and at the same time integrates a standby SNCR denitration interface to realize the synergistic and efficient removal of NO _X after fluid state reconstruction.

4. The separation and return material control system of the present invention adopts a non-mechanical self-balancing return material device to realize the controllable amount of returned material ash, and at the same time integrates the limestone desulfurization interface to realize the synergistic and efficient removal of SO ₂ after fluid state reconstruction. .

5. With the separation and return material control system of the present invention, after realizing the reconfiguration of the flow state, the concentration of large particles in the lower part of the furnace is greatly reduced, thereby reducing the wear of the anti-wear layer in the dense phase area in the lower part of the furnace, especially the interface between the anti-wear layer and the membrane wall wear and tear, improve boiler availability, and achieve safe operation.

6. Using the separation and return material control system of the present invention, after realizing the reconfiguration of the flow state, the material concentration in the secondary air area is reduced when the low-emission circulating fluidized bed boiler is running, the secondary air penetration disturbance effect is enhanced, and the gas-solid upper part of the furnace is solidified. The mixing effect is improved, the combustion efficiency of the boiler is improved, the coal consumption is reduced, and coal-saving combustion is realized; it is easier to form a reducing atmosphere in the lower part of the furnace, suppress the formation of nitrogen oxides, reduce the generation of thermal NO _X , reduce the original emission of NO _X , and achieve low Nitrogen combustion improves the combustion efficiency of the boiler and reduces the generation of pollutants. After realizing the reconfiguration of the flow state, the power required for material fluidization is reduced, the pressure head of the primary and secondary fans of the boiler is reduced, the power consumption of the fans is greatly reduced, and power-saving operation is realized.

7. The slag discharge pipes are arranged on both sides of the bottom of the furnace, and the coarse slag formed after fuel combustion is discharged through the slag discharge regulating valve. The ash discharge and slag pipes are arranged in the middle of the bottom of the furnace, corresponding to the direction in which the return leg is connected to the furnace to control the adjustment of the ash discharge and slag. The valve can discharge the return ash and fine slag formed after fuel combustion.

8. In the integrated method of the present invention, after the fluid state reconstruction, the temperature field in the furnace is more reasonable and uniform, the reaction time of limestone and SO ₂ is longer, the integrated desulfurization in the furnace with low Ca/S is realized, and ultra-low pollutants are achieved. emission, SO ₂ removal efficiency increased to more than 99.8%.

9. In the integrated method of the present invention, after the fluid state reformation, NH ₃ generated by the pyrolysis of urea or ammonia water and NO _X in the flue dust are subjected to SNCR gas phase reaction to remove the NO _X in the flue dust, and the efficient integrated denitrification in the furnace can be achieved. Ultra-low emission of pollutants.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

Description of drawings

Fig. 1 is the overall schematic diagram of the low-emission circulating fluidized bed boiler separation and return material control system and integration method of the present invention;

Figure 2 is a schematic plan layout of the interaction relationship between the slag cooler, the ash cooler, the cooler and the ash remover;

Fig. 3 is a schematic diagram of the plane layout of the interaction relationship between the slag cooler, the ash cooler and the ash remover;

Figure 4 is a schematic diagram of the vertical layout of the interaction between the slag cooler, the ash cooler, the cooler and the ash remover;

Fig. 5 is a partial enlarged view at I of Fig. 1;

Fig. 6 is the partial enlarged view of II place of Fig. 1;

Fig. 7 is the K-K sectional view of Fig. 1;

Fig. 8 is the general assembly schematic diagram of the low-emission circulating fluidized bed boiler utilizing the separation and return material control system of the present invention;

FIG. 9 is a cross-sectional view taken along lines C-C and D-D in FIG. 8 .

Detailed ways

Referring to FIGS. 1-5 , the integrated system for separating and returning materials of a low-emission circulating fluidized bed boiler of the present embodiment includes a furnace 1, a separator 2 and a return material 3; the separation and returning material control system also includes a discharge Slag pipe 6, slag discharge control valve 7, slag cooler 8, ash discharge pipe 9, ash discharge control valve 10, cold ash machine 11, ash discharge pipe 12, ash discharge control valve 13, ash cooler 14 and Ash and slag removal machine 15;

The vertical material pipe 3-1 of the return device 3 is installed on the upper part of the return valve 3-2 of the return device 3, and the return leg 3-3 of the return device 3 is installed on the upper part of the return valve 3-2. On the side, the air cap 3-5 of the return device 3 is installed at the bottom of the return valve 3-2, the air chamber 3-6 of the return device 3 is installed at the lower part of the return valve 3-2, and the ash discharge pipe The inlet end of 12 extends into the air chamber 3-6 and communicates with the bottom of the return valve 3-2, the outlet end of the ash discharge pipe 12 is connected to the ash cooler 14, and the ash discharge regulating valve 13 is installed in the ash cooler 14. On the ash discharge pipe 12, the ash cooler 14 is connected with the ash removal machine 15, the material return leg 3-3 is communicated with the rear lower part of the furnace 1, and the upper edge of the vertical material pipe 3-1 of the material return device 3 A plurality of observation holes 3-4 are arranged vertically, and a limestone desulfurization interface 3-7 is arranged on the return leg 3-3;

The central cylinder 2-1 of the separator 2 includes a fixed cylinder 2-1-1 and a movable cylinder 2-1-2. The fixed cylinder 2-1-1 is installed on the top of the vertical section 2-3 of the separator 2, and the fixed cylinder 2 -1-1 is connected to the tail flue 4, the wall surface of the movable cylinder 2-1-2 is provided with a plurality of groups of through holes along the length direction, the wall surface of the fixed cylinder 2-1-1 is provided with a set of through holes passing through, and the movable cylinder 2-1-2 The position can be adjusted by fixing the pin shaft through a set of through holes and any set of through holes in the fixed cylinder 2-1-1, the length of the center cylinder 2-1 is variable, the inlet and outlet A plurality of SNCR denitration interfaces 2-6 are evenly arranged on the side of the speed regulating section 2-2. The speed regulating section 2-2 of the inlet and outlet of the separator 2 is installed on the side of the vertical section 2-3 of the separator 2. The cone section 2-4 of 3-1 connection;

The bottom of the furnace 1 is installed with a slag discharge pipe 6 and an ash discharge slag pipe 9 at both ends in the length direction. The slag discharge control valve 7 is installed on the slag discharge pipe 6. The slag regulating valve 10 is installed on the ash and slag discharge pipe 9, and the ash and slag discharge pipe 9 is connected with the cold ash and slag machine 11, and the slag cooler 8 and the cold ash and slag machine 11 are respectively connected with the slag remover 15. The hoods 3-5 can be selected from the prior art patent document: CN205299504U.

As shown in Figure 6, the number of observation holes 3-4 is three, the three observation holes 3-4 are vertically arranged in a line, and the distance H1 between two adjacent observation holes is 0.5m. Further, the visible range of the height H of the return ash in the vertical pipe 3-1 is 2-3m, and when the top of the return ash is located at the lower observation hole 3-4 position, H is 2m, and the top of the return ash is 2m. H is 3m at position 3-4 of the upper observation hole. In this embodiment, the amount of returned ash is controlled in a wide range to ensure that the height of the returned ash in the vertical material pipe is H ≥ 2.5m, to prevent ash fall and flue gas back-channeling and coking, and to control the temperature in the furnace within the range of 800-900 °C, This temperature is more suitable for the desulfurization of limestone in the furnace, and the wide-range controllable amount returner provides a suitable temperature range and sufficient reaction time, etc., which increases the utilization rate of limestone, improves the desulfurization efficiency in the furnace, and realizes ultra-low emission of SO ₂ pollutants. In this embodiment, the amount of returned ash is controlled in a wide range to ensure the height of returned ash in the vertical material pipe, and the temperature in the furnace is controlled within the range of 800-900 °C. This temperature can reduce the generation of thermal NO _X and achieve low nitrogen in the furnace. Combustion to achieve ultra-low emission of _NOx pollutants.

Optionally, as shown in FIG. 1 , the thickness of the concrete layer 2-5 in the height direction of the inlet and outlet speed regulating section 2-2 is adjustable. The thickness of the concrete layer 2-5 in the height direction of the inlet and outlet of the inlet and outlet speed regulating section 2-2 increases or decreases simultaneously. By changing the height of the inlet and outlet of the inlet and outlet speed control section, the flue gas flow speed is adjusted, the efficiency of the separator is adjusted, the amount of separated ash is controlled, the furnace bed temperature reaches the design value, the complete combustion of the fuel is achieved, and the energy-saving operation of the boiler is ensured.

Optionally, as shown in FIG. 7 , when the thickness of the concrete layer 2-5 in the width direction at the outlet of the inlet and outlet speed regulating section 2-2 changes, the variation range of the width at the outlet is B1-B2. By adjusting the thickness change of the concrete layer 2-5 in the width direction at the outlet of the inlet and outlet speed regulating section 2-2, the inner side of the outlet of the inlet and outlet speed regulating section 2-2 is aligned with the axis of the vertical section 2-3. The variation range of the included angle of the vertical horizontal line is β2-β1, and the variation range of the outlet width of the inlet and outlet speed regulating section 2-2 is B1-B2. By changing the width of the outlet of the inlet and outlet speed-regulating section to adjust the speed of the flue gas flow, adjust the separation efficiency of the separator structure, control the amount of separated ash, avoid the furnace shutdown caused by unstable combustion, flameout or coking, and ensure the safe operation of the boiler .

8 and 9 are exemplary diagrams of the present invention applied to a low-emission circulating fluidized bed boiler, the main body of the low-emission circulating fluidized bed boiler, the furnace 1 and the returner 3 can be those of the prior art patent document CN207146381U.

Through the SNCR denitration interface 2-6 installed on the side of the speed control section 2-2 of the inlet and outlet, the reducing agent urea solution or ammonia water containing NH _X group is sprayed into the speed control section, and then thermally decomposed into NH ₃ and smoke and dust into the separator , NH ₃ and NO _X in the flue dust undergo SNCR gas-phase reaction to remove NO _X in the flue dust and generate N ₂ and HO ₂ to achieve denitrification in the furnace. The soot entering the separator through the furnace 1 will continue to heat and react CaCO ₃ , the main component of limestone, to generate CaO and _{CO 2} . , CaO absorbs SO ₂ in the soot and generates CaSO ₄ to achieve desulfurization in the furnace. Limestone desulfurization in the furnace is realized by integrating the limestone desulfurization interfaces 3-7 on the return feeder 3 and then feeding limestone; by integrating the SNCR denitration interfaces 2-6 installed on the separator, the SNCR denitrification in the furnace can be realized at low cost and actively. Control the formation of NO _X and the removal of NO _X and SO ₂ in the furnace to achieve ultra-low emission of NO _X and SO ₂ pollutants.

By improving the quality of the boiler bed material, reducing the stock of the bed material, and realizing the reconstruction of the flow state, the temperature field of the furnace is more reasonable and uniform. It enables the boiler to operate in a long-term, safe, stable, energy-saving and environmentally friendly manner, achieves a wide range of boiler load adjustment, and enhances fuel adaptability, forming a separation and return material control system. By using the integrated system for separating and returning materials of the present invention, when the boiler operates at low load or when the fuel suddenly changes, the amount of separated ash, ash and slag, and ash can be controlled individually, or the amount of separated ash and ash and slag, and ash and slag can be controlled jointly. The method of ash discharge realizes that the amount of separated ash, the amount of returned ash and the furnace bed material can be adjusted when the boiler is at low load or when the fuel is suddenly changed, so that the temperature field in the furnace is reasonable and uniform, and the stable temperature is controlled within the range of 800-900 °C to avoid The furnace shutdown caused by unstable combustion, flameout or coking, poor low-nitrogen combustion environment in the furnace and low desulfurization efficiency lead to substandard environmental emissions, and boiler efficiency caused by incomplete combustion of fuel, etc., so that the boiler can operate safely, stably and efficiently for a long time. Ultra-low emissions of NO _X and SO ₂ .

The specific integration method of the control system is as follows:

The first integrated method of low-emission circulating fluidized bed boiler separation and return material control system, which includes the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The ash discharge regulating valve 13 on the ash discharge pipe 12 is closed, the fuel enters the lower part of the furnace 1 through the feeding device 5, is heated by the fluidized high-temperature bed material and burns rapidly, and a large amount of materials generated during the combustion process are carried to the furnace 1 by the flue gas In the upper part, the flue gas carries fine ash from the rear outlet of the upper part of the furnace 1 and enters the inlet and outlet speed regulation section 2-2 of the separator 2, and then enters the vertical section 2-3 of the separator 2 and surrounds the central tube 2-1 for flue gas. separation from fine ash;

Change the length of the movable cylinder 2-1-2 of the central cylinder 2-1, adjust the separation of flue gas and fine ash, reduce or increase the amount of separated ash, and make the returned ash returned to the furnace 1 to stabilize the temperature in the furnace 1 at 800- Between 900°C, the separated ash enters the returner 3 through the cone 2-4 of the separator 2, and the separated ash enters the return valve 3-2 through the vertical leg 3-1 of the returner 3, and part of it returns. The ash is returned to the lower part of the furnace 1 through the return legs 3-3, and the fuel entering the bottom of the furnace 1 through the feeding device 5 is heated, and the fluidized and circular combustion is continued. The separated flue gas enters the tail flue 4 through the central tube 2-1 for replacement After heating, it is discharged out of the furnace;

2. Ash discharge

Close the ash discharge control valve 10 installed on the ash discharge and slag pipe 9 at positions 3-3 of the corresponding return legs, adjust the opening degree of the slag discharge control valve 7 on the slag discharge pipe 6, and eliminate the formation of fuel combustion in the lower part of the furnace 1. The high-temperature large-particle slag is cooled by the slag cooler 8 and then discharged to the slag remover 15, and then transported to the slag bin.

The boiler load decreases, usually the boiler load is below 50%, in order to ensure stable combustion and continuous operation under variable working conditions. By changing the length of the central cylinder 2-1, the efficiency of the separator is adjusted, the amount of separated ash is reduced, and the returned ash returned to the furnace makes the furnace temperature field more reasonable, and stabilizes the temperature in the furnace 1 between 800-900 °C; denitrification through SNCR _The interface 2-6 sprays the reducing agent urea solution or ammonia water containing NH _X group into the speed control section, and then thermally decomposes into NH ₃ and _soot and enters the separator. _NOx and generate N ₂ and HO ₂ to achieve denitrification in the furnace. The soot entering the separator through the furnace 1 will continue to heat and react CaCO ₃ , the main component of limestone, to generate CaO and _{CO 2} . , CaO absorbs SO ₂ in the soot and generates CaSO ₄ to achieve desulfurization in the furnace. The limestone desulfurization in the furnace is realized by integrating the limestone desulfurization interfaces 3-7 on the return feeder 3 and then feeding limestone; through the integration of the SNCR denitration interfaces 2-6 installed on the separator 2, low-cost SNCR denitrification in the furnace can be realized , and actively control the formation of NO _X and the removal of NO _X and SO ₂ in the furnace to achieve ultra-low emission of NO _X and SO ₂ pollutants.

The second integrated method of the low-emission circulating fluidized bed boiler separation and return material control system, which includes the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The ash discharge regulating valve 13 on the ash discharge pipe 12 is closed, the fuel enters the lower part of the furnace 1 through the feeding device 5, is heated by the fluidized high-temperature bed material and burns rapidly, and a large amount of materials generated during the combustion process are carried to the furnace 1 by the flue gas In the upper part, the flue gas carries fine ash from the rear outlet of the upper part of the furnace 1 and enters the inlet and outlet speed regulation section 2-2 of the separator 2, and then enters the vertical section 2-3 of the separator 2 and surrounds the central tube 2-1 for flue gas. separation from fine ash;

The separated separation ash enters the returner 3 through the cone 2-4 of the separator 2, and the separated ash enters the return valve 3-2 through the vertical leg 3-1 of the returner 3, and part of the returned ash passes through the return material. The legs 3-3 return to the lower part of the furnace chamber 1 to heat the fuel that enters the bottom of the furnace chamber 1 through the feeding device 5, and continue to be fluidized and circulated for combustion. The separated flue gas enters the tail smoke through the fixed tube 2-1-1 of the central tube 2-1 Channel 4 is discharged out of the furnace after heat exchange;

2. Ash discharge

Adjust the opening degree of the slag discharge control valve 7 on the slag discharge pipe 6 to remove the large particle slag formed by the combustion of the fuel in the lower part of the furnace 1, and improve the quality of the bed material. The slag machine 15 is transported to the slag bin; the opening degree of the ash discharge and slag control valve 10 installed on the ash discharge and slag pipe 9 at the position of the corresponding return leg 3-3 is adjusted to remove most of the returned ash and a small amount of slag, Reduce the stock of the formed bed material, stabilize the temperature in the furnace 1 between 800-900 ℃, the high temperature ash is cooled by the cold ash machine 11 and then discharged to the ash remover 15 and transported to the slag bin.

The boiler load decreases, usually the boiler load is below 50%, in order to ensure stable combustion and continuous operation under variable working conditions. The amount of returned ash can be reduced to increase the temperature in the furnace. By adjusting the opening of the ash discharge and slag regulating valve 10, most of the returned ash and a small amount of slag returned to the furnace are discharged, reducing the amount of bed material and making the furnace temperature field more stable. Reasonable, the temperature in the stable furnace 1 is between 850-900 °C; through the SNCR denitration interface 2-6, the reducing agent urea solution or ammonia water containing NH _X groups is sprayed into the speed control section, and then thermally decomposed into NH ₃ and smoke and dust enter and separate In the furnace, NH ₃ and NO _X in the flue dust undergo SNCR gas phase reaction to remove NO _X in the flue dust and generate N ₂ and HO ₂ to achieve denitrification in the furnace. The soot entering the separator through furnace 1 will continue to heat and react CaCO ₃ , the main component of limestone, to generate CaO and CO ₂ . SO ₂ generated by fuel combustion diffuses to the surface and inner pores of CaO. , CaO absorbs SO ₂ in the smoke and generates CaSO ₄ to achieve desulfurization in the furnace. The limestone desulfurization in the furnace is realized by integrating the limestone desulfurization interfaces 3-7 on the return feeder 3 and then feeding limestone; through the integration of the SNCR denitration interfaces 2-6 installed on the separator 2, the low-cost SNCR denitrification in the furnace can be realized , actively control the formation of NO _X and NO _X and SO ₂ in the furnace, and realize the ultra-low emission of NO _X and SO ₂ pollutants.

The third integrated method of low-emission circulating fluidized bed boiler separation and return material control system, which includes the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The fuel enters the lower part of the furnace 1 through the feeding device 5, and is heated by the fluidized high-temperature bed material and burns rapidly. A large amount of materials generated during the combustion process are carried to the upper part of the furnace 1 by the flue gas, and the flue gas carries fine ash from the upper part of the furnace 1. Exit Enter the inlet and outlet speed regulation section 2-2 of the separator 2, and then enter the vertical section 2-3 of the separator 2 to separate the flue gas and fine ash around the central tube 2-1;

The separated separation ash enters the returner 3 through the cone 2-4 of the separator 2, and the separated ash enters the return valve 3-2 through the vertical leg 3-1 of the returner 3, and part of the returned ash passes through the return material. The legs 3-3 return to the lower part of the furnace 1, and the fuel entering the bottom of the furnace 1 through the feeding device 5 is heated, and the fuel is continuously fluidized and circulated. , adjust the opening of the ash discharge regulating valve 13 on the ash discharge pipe 12, remove part of the returned ash, control the amount of returned ash returned to the furnace 1, and stabilize the temperature in the furnace 1 between 800-900 ° C;

2. Ash discharge

Close the ash discharge control valve 10 installed on the ash discharge and slag pipe 9 at positions 3-3 of the corresponding return legs, adjust the opening degree of the slag discharge control valve 7 on the slag discharge pipe 6, and eliminate the formation of fuel combustion in the lower part of the furnace 1. The high-temperature large-particle slag is cooled by the slag cooler 8 and then discharged to the ash removal slag machine 15, and transported to the slag bin, and the high-temperature ash is cooled by the ash cooler 14 and then discharged to the ash removal slag machine 15, and transport it to the slag bin.

The boiler load decreases, usually the boiler load is below 50%. In order to ensure stable combustion and continuous operation under variable working conditions, and reduce the amount of returned ash to increase the temperature in the furnace, adjust the opening of the ash discharge regulating valve 13 to remove the returned material. The ash returned in the valve 3-2 is discharged, reducing the stock of the formed bed material, making the furnace temperature field more reasonable, and stabilizing the temperature in the furnace between 800-900 °C; through the SNCR denitration interface 2-6, the NH _X group is reduced _The urea solution or ammonia water is sprayed into the speed control section and then _thermally decomposed into _{NH 3} and _soot , which enter the _separator . Realize denitrification in the furnace. The soot entering the separator through the furnace 1 will continue to heat and react CaCO ₃ , the main component of limestone, to generate CaO and _{CO 2} . , CaO absorbs SO ₂ in the soot and generates CaSO ₄ to achieve desulfurization in the furnace. The limestone desulfurization in the furnace is realized by integrating the limestone desulfurization interfaces 3-7 on the return feeder 3 and then feeding limestone; through the integration of the SNCR denitration interfaces 2-6 installed on the separator 2, low-cost SNCR denitrification in the furnace can be realized , and actively control the formation of NO _X and the removal of NO _X and SO ₂ in the furnace to achieve ultra-low emission of NO _X and SO ₂ pollutants.

The fourth integrated method of low-emission circulating fluidized bed boiler separation and return material control system, which includes the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The ash discharge regulating valve 13 on the ash discharge pipe 12 is closed, the fuel enters the lower part of the furnace 1 through the feeding device 5, is heated by the fluidized high-temperature bed material and burns rapidly, and a large amount of materials generated during the combustion process are carried to the furnace 1 by the flue gas In the upper part, the flue gas carries fine ash from the rear outlet of the upper part of the furnace 1 and enters the inlet and outlet speed regulation section 2-2 of the separator 2, and then enters the vertical section 2-3 of the separator 2 and surrounds the central tube 2-1 for flue gas. separation from fine ash;

Change the length of the movable cylinder 2-1-2 of the central cylinder 2-1, adjust the separation of flue gas and fine ash, reduce or increase the amount of separated ash, and make the returned ash returned to the furnace 1 to stabilize the temperature in the furnace 1 at 800- Between 900°C, the separated ash enters the returner 3 through the cone 2-4 of the separator 2, and the separated ash enters the return valve 3-2 through the vertical leg 3-1 of the returner 3, and part of it returns. The ash is returned to the lower part of the furnace 1 through the return legs 3-3, and the fuel entering the bottom of the furnace 1 through the feeding device 5 is heated, and the fluidized and circular combustion is continued. The separated flue gas enters the tail flue 4 through the central tube 2-1 for replacement After heating, it is discharged out of the furnace;

2. Ash discharge

Adjust the opening degree of the slag discharge control valve 7 on the slag discharge pipe 6 to remove the large particle slag formed by the combustion of the fuel in the lower part of the furnace 1 and improve the quality of the formed bed material. The high temperature large particle slag is cooled by the slag cooler 8 and then discharged to ash removal The slag machine 15 is transported to the slag bin;

Adjust the opening of the ash discharge and slag control valve 10 installed on the ash discharge and slag pipe 9 at positions 3-3 of the corresponding return legs, to remove most of the return ash and a small amount of slag, reduce the stock of the formed bed material, and stabilize the furnace. 1. The internal temperature is between 800-900°C, and the high-temperature ash and slag are cooled by the cold ash-slag machine 11 and then discharged to the ash-removal machine 15 and transported to the slag bin.

The boiler load decreases, usually the boiler load is below 50%. In order to ensure stable combustion and continuous operation under variable working conditions, the efficiency of the separator is adjusted by changing the length of the central tube 2-1, reducing or increasing the amount of separated ash, so that the return The returned ash in the furnace makes the temperature field of the furnace more reasonable. At the same time, the amount of returned ash is reduced to increase the temperature in the furnace. By adjusting the opening of the ash discharge and slag regulating valve 10, most of the returned ash and a small amount of slag are discharged back to the furnace. , reduce the stock of the formed bed material, and make the furnace temperature field more reasonable. Through the integrated measures of controlling the length of the central tube 2-1 and the amount of ash and slag, the temperature in the furnace can be stabilized between 850-900 °C; through the SNCR denitration interface 2- 6. The reducing agent urea solution or ammonia water containing NH _X group is sprayed into the speed control section, and then thermally decomposed into NH ₃ and soot and enter the separator, NH ₃ and NO _X in the soot undergo SNCR gas-phase reaction, and the NO _X in the soot is removed. And generate N ₂ and HO ₂ to achieve denitrification in the furnace. The soot entering the separator through the furnace 1 will continue to heat and react CaCO ₃ , the main component of limestone, to generate CaO and _{CO 2} . , CaO absorbs SO ₂ in the smoke and generates CaSO ₄ to achieve desulfurization in the furnace. The limestone desulfurization in the furnace is realized by integrating the limestone desulfurization interfaces 3-7 on the return feeder 3 and then feeding limestone; through the integration of the SNCR denitration interfaces 2-6 installed on the separator 2, low-cost SNCR denitrification in the furnace can be realized , actively control the formation of NO _X and NO _X and SO ₂ in the furnace, and realize the ultra-low emission of NO _X and SO ₂ pollutants.

The fifth low-emission circulating fluidized bed boiler separation control system and integration method, which includes the following steps:

1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value

The fuel enters the lower part of the furnace 1 through the feeding device 5, and is heated by the fluidized high-temperature bed material and burns rapidly. A large amount of materials generated during the combustion process are carried to the upper part of the furnace 1 by the flue gas, and the flue gas carries fine ash from the upper part of the furnace 1. Exit Enter the inlet and outlet speed regulation section 2-2 of the separator 2, and then enter the vertical section 2-3 of the separator 2 to separate the flue gas and fine ash around the central tube 2-1; the separated separation ash is separated The cone 2-4 of the device 2 enters the return device 3, the separated ash enters the return valve 3-2 through the vertical leg 3-1 of the return device 3, and part of the returned ash returns to the furnace 1 through the return leg 3-3 In the lower part, the fuel entering the bottom of the furnace 1 through the feeding device 5 is heated, and the fluidized and circulating combustion is continued. The separated flue gas enters the tail flue 4 through the central tube 2-1 for heat exchange and is discharged out of the furnace. The opening of the ash discharge regulating valve 13 is adjusted to remove part of the returned ash, control the amount of returned ash returned to the furnace 1, and stabilize the temperature in the furnace 1 between 800-900 °C;

2. Ash discharge

Adjust the opening degree of the slag discharge control valve 7 on the slag discharge pipe 6 to remove the large particle slag formed by the combustion of the fuel in the lower part of the furnace 1 and improve the quality of the formed bed material. The high temperature large particle slag is cooled by the slag cooler 8 and then discharged to ash removal The slag machine 15 is transported to the slag bin;

Adjust the opening of the ash discharge and slag control valve 10 installed on the ash discharge and slag pipe 9 at positions 3-3 of the corresponding return legs, to remove most of the return ash and a small amount of slag, reduce the stock of the formed bed material, and stabilize the furnace. 1. The internal temperature is between 800-900°C. The high-temperature ash is cooled by the ash cooler 11 and then discharged to the ash remover 15 and transported to the slag bin. The high-temperature ash is cooled by the ash cooler 14 and then discharged to the ash remover. 15. Transport to the slag bin.

The boiler load decreases, usually the boiler load is below 50%. In order to ensure stable combustion and continuous operation under variable working conditions, the amount of returned ash can be reduced to increase the temperature in the furnace. By adjusting the opening of the ash discharge and slag regulating valve 10, most of the returned ash and a small amount of slag returned to the furnace are discharged, so as to reduce the stock of the formed bed material and make the furnace temperature field more reasonable. At the same time, the amount of returned ash is reduced to improve the furnace chamber. Internal temperature, by adjusting the opening of the ash discharge regulating valve 13, the ash returned in the return valve 3-2 is discharged, reducing the stock of the formed bed material and making the furnace temperature field more reasonable. The integrated measures of ash amount stabilize the temperature in the furnace between 800-900 °C; through the SNCR denitration interface 2-6, the reducing agent urea solution or ammonia water containing NH _X group is sprayed into the speed control section, and then thermally decomposed into NH ₃ and dust entering Separator, NH ₃ and NO _X in flue dust carry out SNCR gas phase reaction to remove NO _X in flue dust and generate N ₂ and HO ₂ to realize denitrification in furnace. The soot entering the separator through the furnace 1 will continue to heat and react CaCO ₃ , the main component of limestone, to generate CaO and _{CO 2} . , CaO absorbs SO ₂ in the smoke and generates CaSO ₄ to achieve desulfurization in the furnace. The limestone desulfurization in the furnace is realized by integrating the limestone desulfurization interfaces 3-7 on the return feeder 3 and then feeding limestone; through the integration of the SNCR denitration interfaces 2-6 installed on the separator 2, low-cost SNCR denitrification in the furnace can be realized , actively control the formation of NO _X and NO _X and SO ₂ in the furnace, and realize the ultra-low emission of NO _X and SO ₂ pollutants.

The present invention has been disclosed above with preferred implementation examples, but it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make the above implementation examples according to the technical essence of the present invention. Any simple modifications, equivalent changes and modifications still fall within the scope of the technical solution of the present invention.

Claims (10)

1. The low-emission type circulating fluidized bed boiler separation and return material control system, it comprises furnace (1), separator (2) and return material device (3); it is characterized in that: described separation return material control integrated system also includes Slag discharge pipe (6), slag discharge control valve (7), slag cooler (8), ash discharge pipe (9), ash discharge control valve (10), cold ash machine (11), ash discharge pipe (12), ash discharge regulating valve (13), ash cooler (14) and ash removal machine (15); The vertical material pipe (3-1) of the reverter (3) is installed on the upper part of the revert valve (3-2) of the reverter (3), and the reverter leg (3-3) of the reverter (3) ) is installed on the side of the return valve (3-2), the air cap (3-5) of the return device (3) is installed at the bottom of the return valve (3-2), and the return device (3) The air chamber (3-6) is installed at the lower part of the return valve (3-2), and the inlet end of the ash discharge pipe (12) extends into the air chamber (3-6) and the return valve ( 3-2) The bottom is connected, the outlet end of the ash discharge pipe (12) is connected with the ash cooler (14), the ash discharge regulating valve (13) is installed on the ash discharge pipe (12), the The ash cooler (14) is connected with the ash remover (15), the material returning leg (3-3) is communicated with the rear lower part of the furnace (1), and the vertical material pipe (3-1) of the material returning device (3) A plurality of observation holes (3-4) are arranged vertically along the upper edge, and a limestone desulfurization interface (3-7) is arranged on the return leg (3-3); The central cylinder (2-1) of the separator (2) includes a fixed cylinder (2-1-1) and a movable cylinder (2-1-2), and the fixed cylinder (2-1-1) is installed on the separator (2) At the top of the vertical section (2-3) of the duct, the fixed cylinder (2-1-1) is connected to the tail flue (4), and the wall of the movable cylinder (2-1-2) is provided with a plurality of groups of through holes along the length direction, A set of through holes are formed on the wall of the fixed cylinder (2-1-1), and the movable cylinder (2-1-2) is fixed on the fixed cylinder ( 2-1-1), the position can be adjusted, the length of the center cylinder (2-1) can be changed, and the inlet and outlet speed control sections (2-2) of the separator (2) are installed in the vertical section of the separator (2). (2-3) On the side, a plurality of SNCR denitration interfaces (2-6) are evenly arranged on the side of the inlet and outlet speed regulating section (2-2), and the cone section (2-4) of the separator (2) Installed at the lower part of the vertical section (2-3), the inlet and outlet speed regulation section (2-2) is connected to the upper rear outlet of the furnace (1), and the cone section (2-4) is connected to the vertical material Pipe (3-1) connection; A slag discharge pipe (6) and an ash discharge pipe (9) are respectively installed on the bottom of the furnace (1) at both ends in the length direction, and a slag discharge control valve (7) is installed on the slag discharge pipe (6). (6) Connected to the slag cooler (8), the ash discharge control valve (10) is installed on the ash discharge pipe (9), and the ash discharge pipe (9) is connected with the cold ash machine (11), and the slag cold The machine (8) and the cold ash machine (11) are respectively connected with the ash removal machine (15). 2. The low-emission circulating fluidized bed boiler separation and return material control system according to claim 1 is characterized in that: the number of observation holes (3-4) is three, and the three observation holes (3-4) are vertical Arranged in a line, the distance H1 between two adjacent observation holes is 0.5m. 3. The low-emission circulating fluidized bed boiler separation and return material control system according to claim 2, is characterized in that: the return material ash height H in the vertical material pipe (3-1) can be seen in a range of 2-3m, and When the top of the returned ash is located at the lower observation hole (3-4), H is 2m, and when the top of the returned ash is located at the upper observation hole (3-4), H is 3m. 4. The low-emission circulating fluidized bed boiler separation and return material control system according to claim 1, 2 or 3, characterized in that: a concrete layer (2) in the height direction of the inlet and outlet speed regulation sections (2-2) -5) The thickness is adjustable. 5. The low-emission circulating fluidized bed boiler separation and return material control system according to claim 4, characterized in that: the outlet of the inlet and outlet speed regulation sections (2-2) is located on the concrete layer (2-2) in the width direction. When the thickness of 5) changes, the variation range of the width at the outlet is B1-B2. 6. the integrated method of the low-emission circulating fluidized bed boiler separation and return material control system as claimed in claim 1, is characterized in that: it comprises the steps: 1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value The ash discharge regulating valve (13) on the ash discharge pipe (12) is closed, and the fuel enters the lower part of the furnace (1) through the feeding device (5), and is heated by the fluidized high temperature bed material and burns rapidly. The material is carried to the upper part of the furnace (1) by the flue gas, and the fine ash is carried by the flue gas from the upper rear outlet of the furnace (1) into the inlet and outlet speed regulation section (2-2) of the separator (2), and then enters the separator (2). ) in the vertical section (2-3) around the central cylinder (2-1) to separate the flue gas and fine ash; Change the length of the movable cylinder (2-1-2) of the central cylinder (2-1), adjust the separation of flue gas and fine ash, reduce or increase the amount of separated ash, so that the returned ash returned to the furnace (1) can stabilize the furnace. (1) The internal temperature is between 800-900°C, the separated separated ash enters the reverter (3) through the cone (2-4) of the separator (2), and the separated ash passes through the reverter (3). The vertical feed leg (3-1) enters the return valve (3-2), and part of the returned ash returns to the lower part of the furnace (1) through the return leg (3-3), and the heating enters the furnace (1) through the feeding device (5). ) The fuel at the bottom is continuously fluidized and cyclically burned, and the separated flue gas enters the tail flue (4) through the central tube (2-1) and is discharged out of the furnace after heat exchange; 2. Ash discharge Close the ash discharge control valve (10) installed on the ash discharge pipe (9) at the position of the corresponding return leg (3-3), and adjust the slag discharge control valve (7) on the slag discharge pipe (6) to open. The high-temperature large-particle slag is cooled by the slag cooler (8) and then discharged to the ash remover (15) and transported to the slag bin. 7. The integrated method of the low-emission circulating fluidized bed boiler separation and return material control system as claimed in claim 1, it is characterized in that: it comprises the following steps: 1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value The ash discharge regulating valve (13) on the ash discharge pipe (12) is closed, and the fuel enters the lower part of the furnace (1) through the feeding device (5), and is heated by the fluidized high temperature bed material and burns rapidly. The material is carried to the upper part of the furnace (1) by the flue gas, and the fine ash is carried by the flue gas from the upper rear outlet of the furnace (1) into the inlet and outlet speed regulation section (2-2) of the separator (2), and then enters the separator (2). ) in the vertical section (2-3) around the central cylinder (2-1) to separate the flue gas and fine ash; The separated separation ash enters the returner (3) through the cone (2-4) of the separator (2), and the separated ash enters the return valve (3-1) through the vertical material leg (3-1) of the returner (3). 3-2), part of the returning ash is returned to the lower part of the furnace (1) through the returning legs (3-3), and the fuel entering the bottom of the furnace (1) through the feeding device (5) is heated, and the fluidized and circulating combustion is continued. The flue gas passed through the central tube (2-1) enters the tail flue (4) after heat exchange and is discharged out of the furnace; 2. Ash discharge Adjust the opening of the slag discharge regulating valve (7) on the slag discharge pipe (6) to remove the large particle slag formed by the combustion of the fuel in the lower part of the furnace (1). The ash and slag machine (15) is transported to the slag bin; the opening of the ash-discharge and slag control valve (10) installed on the ash-discharge and slag pipe (9) at the position of the corresponding return leg (3-3) is adjusted to increase the Part of the returned ash and a small amount of slag are removed to reduce the stock of the formed bed material and stabilize the temperature in the furnace (1) between 800-900 °C. (15), transported to the slag bin. 8. The integrated method of the low-emission circulating fluidized bed boiler separation and return material control system according to claim 1, characterized in that: it comprises the following steps: 1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value The fuel enters the lower part of the furnace (1) through the feeding device (5), and is heated by the fluidized high-temperature bed material and burns rapidly. A large amount of materials generated during the combustion process are carried to the upper part of the furnace (1) by the flue gas, and the fine ash is carried by the flue gas. From the upper rear outlet of the furnace (1), it enters the inlet and outlet speed regulating section (2-2) of the separator (2), and then enters the vertical section (2-3) of the separator (2) to surround the central cylinder (2-2). 1) Separation of flue gas and fine ash; The separated separation ash enters the returner (3) through the cone (2-4) of the separator (2), and the separated ash enters the return valve (3-1) through the vertical material leg (3-1) of the returner (3). 3-2), part of the returning ash is returned to the lower part of the furnace (1) through the returning legs (3-3), and the fuel entering the bottom of the furnace (1) through the feeding device (5) is heated, and the fluidized and circulating combustion is continued. The flue gas from the central tube (2-1) enters the tail flue (4) after heat exchange and is discharged out of the furnace. The opening of the ash discharge regulating valve (13) on the ash discharge pipe (12) is adjusted, and part of the returned ash is discharged. Eliminate and control the amount of ash returned to the furnace (1), and stabilize the temperature in the furnace (1) between 800-900 °C; 2. Ash discharge Close the ash discharge control valve (10) installed on the ash discharge pipe (9) at the position of the corresponding return leg (3-3), and adjust the slag discharge control valve (7) on the slag discharge pipe (6) to open. The high-temperature large-particle slag is cooled by the slag cooler (8) and then discharged to the ash remover (15), and then transported to the slag bin, where the high-temperature ash is cooled by the slag cooler (8). The machine (14) is cooled and then discharged to the ash removal machine (15) and transported to the slag bin. 9. The integrated method of the low-emission circulating fluidized bed boiler separation and return material control system as claimed in claim 1, characterized in that: it comprises the steps: 1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value The ash discharge regulating valve (13) on the ash discharge pipe (12) is closed, and the fuel enters the lower part of the furnace (1) through the feeding device (5), and is heated by the fluidized high temperature bed material and burns rapidly. The material is carried to the upper part of the furnace (1) by the flue gas, and the fine ash is carried by the flue gas from the upper rear outlet of the furnace (1) into the inlet and outlet speed regulation section (2-2) of the separator (2), and then enters the separator (2). ) in the vertical section (2-3) around the central cylinder (2-1) to separate the flue gas and fine ash; Change the length of the movable cylinder (2-1-2) of the central cylinder (2-1), adjust the separation of flue gas and fine ash, reduce or increase the amount of separated ash, and make the returned ash returned to the furnace (1) to stabilize the furnace. (1) The internal temperature is between 800-900°C, the separated separated ash enters the reverter (3) through the cone (2-4) of the separator (2), and the separated ash passes through the reverter (3). The vertical feed leg (3-1) enters the return valve (3-2), and part of the returned ash returns to the lower part of the furnace (1) through the return leg (3-3), and the heating enters the furnace (1) through the feeding device (5). ) The fuel at the bottom is continuously fluidized and cyclically burned, and the separated flue gas enters the tail flue (4) through the central tube (2-1) and is discharged out of the furnace after heat exchange; 2. Ash discharge Adjust the opening of the slag discharge control valve (7) on the slag discharge pipe (6) to remove the large particle slag formed by the combustion of the fuel in the lower part of the furnace (1). The ash machine (15) is transported to the slag bin; Adjust the opening of the ash discharge and slag control valve (10) installed on the ash discharge and slag pipe (9) at the position of the corresponding return leg (3-3) to remove most of the return ash and a small amount of slag, and reduce the formation of bed In order to stabilize the temperature in the furnace (1) between 800-900 °C, the high temperature ash is cooled by the cold ash machine (11) and then discharged to the ash remover (15) and transported to the slag bin. 10. The integrated method of the low-emission circulating fluidized bed boiler separation and return material control system according to claim 1, characterized in that: it comprises the following steps: 1. Fuel combustion, flue gas and ash separation under reduced boiler load or reduced fuel calorific value The fuel enters the lower part of the furnace (1) through the feeding device (5), is heated by the fluidized high-temperature bed material and burns rapidly, and a large amount of materials generated during the combustion process are carried to the upper part of the furnace (1) by the flue gas, and the fine ash is carried by the flue gas. From the upper rear outlet of the furnace (1), it enters the inlet and outlet speed regulating section (2-2) of the separator (2), and then enters the vertical section (2-3) of the separator (2) to surround the central cylinder (2-2). 1) Separation of flue gas and fine ash; The separated separation ash enters the returner (3) through the cone (2-4) of the separator (2), and the separated ash enters the return valve (3-1) through the vertical material leg (3-1) of the returner (3). 3-2), part of the returning ash is returned to the lower part of the furnace (1) through the returning legs (3-3), and the fuel entering the bottom of the furnace (1) through the feeding device (5) is heated, and the fluidized and circulating combustion is continued. The flue gas from the central tube (2-1) enters the tail flue (4) after heat exchange and is discharged out of the furnace. The opening of the ash discharge regulating valve (13) on the ash discharge pipe (12) is adjusted, and part of the returned ash is discharged. Eliminate and control the amount of ash returned to the furnace (1), and stabilize the temperature in the furnace (1) between 800-900 °C; 2. Ash discharge Adjust the opening of the slag discharge control valve (7) on the slag discharge pipe (6) to remove the large particle slag formed by the combustion of the fuel in the lower part of the furnace (1). The ash machine (15) is transported to the slag bin; Adjust the opening of the ash discharge and slag control valve (10) installed on the ash discharge and slag pipe (9) at the position of the corresponding return leg (3-3) to remove most of the return ash and a small amount of slag, and reduce the formation of bed The temperature in the stable furnace (1) is between 800-900 °C, the high temperature ash is cooled by the cold ash machine (11) and then discharged to the ash remover (15), and then transported to the slag bin. The ash cooler (14) is cooled and then discharged to the ash remover (15) and transported to the slag bin.

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