阅读说明：本技术 一种基于水煤浆循环流化床低氮燃烧控制系统 (Low-nitrogen combustion control system based on water-coal-slurry circulating fluidized bed ) 是由 王海峰 张刚 安亮 王海涛 于祥红 孙鹏 于 2020-07-21 设计创作，主要内容包括：本发明公开了一种基于水煤浆循环流化床低氮燃烧控制系统,包括流化床,流化床的底部连接二次进风管,流化床的侧壁中部连接第一分离器,第一分离器连接分解装置,分解装置连接一次进风管和供浆泵,流化床的顶部连接第二分离器,第二分离器连接送烟管,送烟管连接保温箱,保温箱套接排烟管,一次进风管和二次进风管均通过循环管连接排烟管,循环管上均安装循环风机。分解机构将水煤浆与一次进风在缺氧条件下进行热解,产生大量还原性气体,并将生成的NOx全部还原为N2,减少NOx,水煤浆进入主燃烧区与二次进风进行充分燃烧,还原气体通过第一分离器进入流化床,主燃烧区产生的NOx与还原气体进行还原反应,进一步降低NOx的排放浓度,提高低氮燃烧性能。(The invention discloses a low-nitrogen combustion control system based on a water-coal-slurry circulating fluidized bed, which comprises a fluidized bed, wherein the bottom of the fluidized bed is connected with a secondary air inlet pipe, the middle part of the side wall of the fluidized bed is connected with a first separator, the first separator is connected with a decomposition device, the decomposition device is connected with a primary air inlet pipe and a slurry supply pump, the top of the fluidized bed is connected with a second separator, the second separator is connected with a smoke feeding pipe, the smoke feeding pipe is connected with a heat preservation box, the heat preservation box is sleeved with a smoke exhaust pipe, the primary air inlet pipe and the secondary air inlet pipe are both connected with the smoke exhaust pipe through circulating. The decomposition mechanism pyrolyzes the water-coal-slurry and the primary air under the anoxic condition to generate a large amount of reducing gas, and reduces the generated NOx to N2 completely, the water-coal-slurry enters the main combustion area to be fully combusted with the secondary air, the reducing gas enters the fluidized bed through the first separator, the NOx generated in the main combustion area and the reducing gas perform a reduction reaction, the emission concentration of the NOx is further reduced, and the low-nitrogen combustion performance is improved.)

1. The utility model provides a low nitrogen combustion control system based on coal slurry circulating fluidized bed, includes fluidized bed (1), its characterized in that: the bottom of the fluidized bed (1) is fixedly connected with a secondary air inlet pipe (10), the middle part of the side wall of the fluidized bed (1) is connected with a first separator (2), the first separator (2) is connected with the outlet end of a decomposition device (3), the inlet end of the decomposition device (3) is connected with a primary air inlet pipe (9) and a slurry supply pump (4), the top of the fluidized bed (1) is fixedly connected with a second separator (5), the gas phase outlet of the second separator (5) is connected with one end of a flue gas delivery pipe (6), the other end of the flue gas delivery pipe (6) is fixedly connected with one end of a heat preservation box (7), an air preheater (8) is installed in the heat preservation box (7), the primary air inlet pipe (9) and the secondary air inlet pipe (10) are both connected with the air preheater (8), and air blowers (11) are both installed at the air inlets of the primary air inlet pipe (9) and the secondary air, the fixed cover of the other end of insulation can (7) connects fume exhaust pipe (12), install draught fan (13) on fume exhaust pipe (12), the equal fixed connection circulating pipe (14) of one end that once air-supply line (9) and secondary air-supply line (10) are close to forced draught blower (11), the other end of circulating pipe (14) is all fixed to be cup jointed and is discharged fume pipe (12), and all installs circulating fan (15) on circulating pipe (14).

2. The low-nitrogen combustion control system based on the coal-water slurry circulating fluidized bed according to claim 1, characterized in that: fluidized bed (1) includes furnace (102), furnace (102) bottom fixed mounting plenum (101), secondary air inlet pipe (10) is connected in plenum (101), furnace (102) inner chamber from the bottom up divide into main combustion area (103), reduction zone (104) and burnout zone (105) in proper order, gas phase outlet connection reduction zone (104) of first separator (2), burnout zone (105) is connected to the entry end of second separator (5), the solid-liquid phase exit linkage main combustion area (103) of first separator (2) and second separator (5).

3. The low-nitrogen combustion control system based on the coal-water slurry circulating fluidized bed according to claim 2, characterized in that: the combustor (17) is fixedly installed on the inner wall of the main combustion area (103) close to the solid-liquid phase outlet of the first separator (2), and the first separator (2) and the second separator (5) are gravity separators.

4. The low-nitrogen combustion control system based on the coal-water slurry circulating fluidized bed according to claim 1, characterized in that: decomposing device (3) are including neck reducing pipe (31), an air-supply line (9) of one end fixed connection of neck reducing pipe (31), the one end of the other end fixed connection larynx neck (32) of neck reducing pipe (31), the one end of the other end fixed connection expansion pipe (33) of larynx neck (32), and expansion pipe (33) are close to the one end outer wall of larynx neck (32) and pass through the export that the inlet pipe is connected and is supplied stuff pump (4), the one end in other end fixed connection decomposition chamber (35) of expansion pipe (33), the entry of the first separator (2) of the other end fixed connection in decomposition chamber (35), decomposition chamber (35) are close to inner wall fixed mounting some firearm (34) of expansion pipe (33), decompose a plurality of thermocouples (36) of even installation of chamber (35) inner wall.

5. The coal water slurry circulating fluidized bed-based low-nitrogen combustion control system according to claim 4, characterized in that: the neck reducing pipe (31) and the expansion pipe (33) are both of a hollow circular truncated cone structure, the small diameter ends of the neck reducing pipe (31) and the expansion pipe (33) are fixedly connected with the throat part (32) respectively, and the neck reducing pipe (31), the throat part (32) and the expansion pipe (33) form a Venturi tube structure.

6. The coal water slurry circulating fluidized bed-based low-nitrogen combustion control system according to claim 4, characterized in that: the decomposition cavity (35) is of an inclined downward structure, the number of the thermocouples (36) is three, a group of thermocouples (36) is arranged on the inner walls of the front section, the middle section and the rear section of the decomposition cavity (35), and the number of each group of thermocouples (36) is two.

7. The low-nitrogen combustion control system based on the coal-water slurry circulating fluidized bed according to claim 1, characterized in that: bolt installation closing plate is passed through to one side of insulation can (7), air heater (8) are including division board (82), inner chamber top fixed mounting division board (82) of insulation can (7), evenly seted up a plurality of gas outlets (83) on division board (82), a plurality of guide plates (81) of insulation can (7) inner wall fixed mounting at division board (82) top, two heat exchange tubes (84), two of insulation can (7) inner chamber fixed mounting of division board (82) bottom air-supply line (9) and secondary air-supply line (10) are connected respectively to heat exchange tube (84), fixed mounting helical fin (85) on the outer wall of heat exchange tube (84).

8. The low-nitrogen combustion control system based on the coal-water slurry circulating fluidized bed according to claim 7, characterized in that: the top of the guide plate (81) is over against the outlet of the smoke delivery pipe (6), the bottom of the guide plate (81) is inclined towards the side walls of the two sides of the heat preservation box (7), and the heat exchange pipe (84) is of a bent snake-shaped structure formed by connecting a plurality of U-shaped pipes end to end.

9. The low-nitrogen combustion control system based on the coal-water slurry circulating fluidized bed according to claim 1, characterized in that: a dust remover (16) is arranged on a smoke exhaust pipe (12) between the heat insulation box (7) and the induced draft fan (13), and one-way valves are arranged on circulating pipes (14) at two ends of the circulating fan (15).

10. The low-nitrogen combustion control system based on the coal-water slurry circulating fluidized bed according to claim 1, characterized in that: supply thick liquid pump (4), forced draught blower (9), draught fan (13) and circulating fan (15) equal electricity to be connected with industrial computer (20), it is a plurality of DSC system (18) are connected in industrial computer (20), equal sensor (19) in fluidized bed (1), insulation can (7) and the pipe (12) of discharging fume, DSC system (18) are connected to sensor (19) electricity.

Technical Field

The invention relates to the technical field of coal water slurry combustion, in particular to a low-nitrogen combustion control system based on a coal water slurry circulating fluidized bed.

Background

Coal-based clean fuel coal water slurry for burning of a circulating fluidized bed boiler is an effective combustion mode for reducing smoke pollutants, but in the actual operation and use process of the boiler, along with the adjustment of dynamic variables of the boiler required by the outside, particularly in the low-load operation, the operation oxygen amount is higher, the control capability of nitrogen oxides is lower, the concentration of the generated nitrogen oxides is higher, the concentration is about 300mg/Nm3, and the environment is seriously polluted.

Disclosure of Invention

The invention aims to provide a low-nitrogen combustion control system based on a water-coal-slurry circulating fluidized bed, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a low-nitrogen combustion control system based on a coal water slurry circulating fluidized bed comprises a fluidized bed, wherein a secondary air inlet pipe is fixedly connected to the bottom of the fluidized bed, a first separator is connected to the middle of the side wall of the fluidized bed, the first separator is connected with the outlet end of a decomposition device, the inlet end of the decomposition device is connected with a primary air inlet pipe and a slurry supply pump, a second separator is fixedly connected to the top of the fluidized bed, the gas phase outlet of the second separator is connected with one end of a smoke delivery pipe, the other end of the smoke delivery pipe is fixedly connected with one end of a heat preservation box, an air preheater is installed in the heat preservation box, the primary air inlet pipe and the secondary air inlet pipe are both connected with an air preheater, air feeders are both installed at air inlets of the primary air inlet pipe and the secondary air inlet pipe, a smoke discharge pipe is fixedly sleeved at the other end of the heat preservation box, an induced draft fan is installed on the, the other end of the circulating pipe is fixedly sleeved with a smoke exhaust pipe, and the circulating pipe is provided with a circulating fan.

In a preferred embodiment, the fluidized bed includes a furnace, an air chamber is fixedly installed at the bottom of the furnace, the air chamber is connected with a secondary air inlet pipe, an inner cavity of the furnace is sequentially divided into a main combustion area, a reduction area and a burnout area from bottom to top, a gas phase outlet of the first separator is connected with the reduction area, an inlet end of the second separator is connected with the burnout area, and solid-liquid phase outlets of the first separator and the second separator are connected with the main combustion area.

In a preferred embodiment, the burner is fixedly installed on the inner wall of the main combustion zone near the solid-liquid phase outlet of the first separator, and the first separator and the second separator are both gravity separators.

An embodiment of preferred, decomposition device includes the neck draw pipe, the air-supply line once of one end fixed connection of neck draw pipe, the one end of the other end fixed connection larynx neck of neck draw pipe, the one end of the other end fixed connection expansion pipe of larynx neck, and the expansion pipe is close to the export of one end outer wall of larynx neck and pass through the inlet pipe and connect the confession thick liquid pump, the one end in chamber is decomposed to the other end fixed connection of expansion pipe, the entry of the first separator of the other end fixed connection in chamber is decomposed, decompose the inner wall fixed mounting point firearm that the chamber is close to the expansion pipe, decompose a plurality of thermocouples of intracavity wall evenly installed.

In a preferred embodiment, the neck reducing pipe and the expanding pipe are both hollow truncated cone structures, the small-diameter ends of the neck reducing pipe and the expanding pipe are respectively and fixedly connected with the throat part, and the neck reducing pipe, the throat part and the expanding pipe form a venturi tube structure.

In a preferred embodiment, the decomposition chamber is in an inclined downward structure, the number of the thermocouples is three, a group of thermocouples is mounted on the inner walls of the front section, the middle section and the rear section of the decomposition chamber, and the number of the thermocouples in each group is two.

In an embodiment of the invention, a bolt is used for installing a sealing plate on one side of the insulation can, the air preheater comprises a partition plate, the partition plate is fixedly installed above the inner cavity of the insulation can, a plurality of air outlets are uniformly formed in the partition plate, a plurality of guide plates are fixedly installed on the inner wall of the insulation can at the top of the partition plate, two heat exchange tubes are fixedly installed in the inner cavity of the insulation can at the bottom of the partition plate and are respectively connected with a primary air inlet tube and a secondary air inlet tube, and spiral fins are fixedly installed on the outer wall of each heat exchange.

In an embodiment of the present invention, the top of the guide plate faces the outlet of the smoke delivery pipe, the bottom of the guide plate is inclined toward the side walls of the two sides of the heat preservation box, and the heat exchange pipe is a curved serpentine structure formed by connecting a plurality of U-shaped pipes end to end.

In a preferred embodiment, a dust remover is arranged on a smoke exhaust pipe between the heat insulation box and the induced draft fan, and one-way valves are arranged on circulating pipes at two ends of the circulating fan.

The preferred embodiment, the equal electricity of confession stuff pump, forced draught blower, draught fan and circulating fan is connected with the industrial computer, and is a plurality of the DSC system is connected to the industrial computer, equal sensor in fluidized bed, insulation can and the smoke exhaust pipe, the DSC system is connected to the sensor electricity.

Compared with the prior art, the invention has the beneficial effects that:

1. pyrolyzing the coal water slurry and the primary inlet air through a decomposition mechanism under the anoxic condition to generate a large amount of reducing gases containing hydrogen, carbon monoxide, methane and the like, and completely reducing the generated NOx into N2, so as to primarily reduce the NOx;

2. the coal water slurry enters a main combustion area and is fully combusted in combination with secondary air blown out from an air chamber, reducing gas directly enters a reduction area through a first separator, and NOx generated in the main combustion area is subjected to reduction reaction with the reducing gas in the reduction area, so that the emission concentration of the NOx is further reduced;

3. the second separator separates the flue gas and sends the flue gas into the heat insulation box through the blast pipe, and preheats the air in the primary air inlet pipe and the secondary air inlet pipe through the air preheater, so that the coal water slurry pyrolysis and combustion energy consumption are reduced, and the energy utilization rate is improved;

4. the DSC system monitors the bed temperature and the bed pressure in the fluidized bed through the sensor, and the oxygen content and the NOx concentration in the insulation can and the smoke exhaust pipe, thereby controlling the power of a slurry supply pump, a blower, an induced draft fan and a circulating fan through an industrial personal computer, controlling the air supply quantity of the blower, extracting the smoke in the smoke exhaust pipe through the circulating fan and a circulating pipe, mixing the smoke with primary air inlet and secondary air inlet, adjusting the oxygen content in the fluidized bed, avoiding the generation of a large amount of NOx caused by the excessive oxygen content, and improving the low-nitrogen combustion performance.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of an air preheater according to the present invention;

FIG. 3 is an enlarged view of the structure at A in FIG. 1 according to the present invention.

In the figure: 1 fluidized bed, 101 air chamber, 102 hearth, 103 main combustion zone, 104 reduction zone, 105 burnout zone, 2 first separator, 3 decomposition device, 31 neck shrinkage pipe, 32 throat, 33 expansion pipe, 34 igniter, 35 decomposition cavity, 36 thermocouple, 4 slurry supply pump, 5 second separator, 6 flue gas sending pipe, 7 insulation box, 8 air preheater, 81 guide plate, 82 partition plate, 83 air outlet, 84 heat exchange pipe, 85 spiral fin, 9 primary air inlet pipe, 10 secondary air inlet pipe, 11 air inlet machine, 12 smoke outlet pipe, 13 draught fan, 14 circulation pipe, 15 circulation fan, 16 dust remover, 17 burner, 18DSC system, 19 sensor, 20 industrial personal computer.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-3, the present invention provides a technical solution: a low-nitrogen combustion control system based on a coal water slurry circulating fluidized bed comprises a fluidized bed 1, wherein the bottom of the fluidized bed 1 is fixedly connected with a secondary air inlet pipe 10, the middle part of the side wall of the fluidized bed 1 is connected with a first separator 2, the first separator 2 is connected with the outlet end of a decomposition device 3, the inlet end of the decomposition device 3 is connected with a primary air inlet pipe 9 and a slurry supply pump 4, the top of the fluidized bed 1 is fixedly connected with a second separator 5, the gas phase outlet of the second separator 5 is connected with one end of a flue gas delivery pipe 6, the other end of the flue gas delivery pipe 6 is fixedly connected with one end of a heat preservation box 7, an air preheater 8 is arranged in the heat preservation box 7, the primary air inlet pipe 9 and the secondary air inlet pipe 10 are both connected with the air preheater 8, air blowers 11 are respectively arranged at air inlets of the primary air inlet pipe 9 and the secondary air inlet pipe 10, a smoke exhaust pipe 12 is fixedly sleeved on the other end of the heat, the other end of the circulating pipe 14 is fixedly sleeved with the smoke exhaust pipe 12, and the circulating pipe 14 is provided with a circulating fan 15. The primary air inlet pipe 9 and the secondary air inlet pipe 10 respectively provide air for the decomposition device 3 and the fluidized bed 1 through the blower 11, the slurry supply pump 4 sends coal water slurry into the decomposition device 3 to be thermally decomposed with primary air under the anoxic condition to generate reductive gas containing hydrogen, carbon monoxide, methane and the like, and the generated NOx is completely reduced to N2, NOx is primarily reduced, the gas and the coal water slurry are separated through the first separator 2, the coal water slurry continuously enters the fluidized bed 1 to be mainly combusted with secondary air, the generated NOx is subjected to reduction reaction with the reductive gas separated from the first separator 2, the NOx content is further reduced, the flue gas separated by the second separator 5 preheats the primary air inlet and the secondary air inlet through the air preheater 8, the combustion energy consumption is reduced, the energy utilization rate is improved, the flue gas is extracted through the circulating fan 15 and the circulating pipe 14 to enter the primary air inlet and the secondary air inlet, the oxygen content of the air is reduced, the generation amount of NOx is further reduced, and the low-nitrogen combustion control effect is achieved.

Fluidized bed 1 includes furnace 102, furnace 102 bottom fixed mounting plenum 101, secondary air-supply line 10 is connected to plenum 101, furnace 102 inner chamber from the bottom up divide into main combustion area 103 in proper order, reduction zone 104 and burnout district 105, the gaseous phase exit linkage reduction zone 104 of first separator 2, burnout district 105 is connected to the entry end of second separator 5, the solid-liquid phase exit linkage main combustion area 103 of first separator 2 and second separator 5, then the coal slurry mixes the secondary air in main combustion area 103 and carries out main burning, the reduction gas directly gets into reduction zone 104 through first separator 2, the NOx that main combustion area 103 produced carries out the reduction reaction at reduction zone 104 with the reduction gas, reduce NOx concentration, and the reduction gas further fully burns, finally burn totally and discharge into second separator 5 at burnout district 105.

The combustor 17 is fixedly arranged on the inner wall of the main combustion area 103 close to the solid-liquid phase outlet of the first separator 2, so that the coal water slurry and the secondary air can be combusted fully, and the first separator 2 and the second separator 5 are both gravity separators.

The decomposing device 3 comprises a necking pipe 31, one end of the necking pipe 31 is fixedly connected with a primary air inlet pipe 9, the other end of the necking pipe 31 is fixedly connected with one end of a throat part 32, the other end of the throat part 32 is fixedly connected with one end of an expansion pipe 33, the outer wall of one end of the expansion pipe 33 close to the throat part 32 is connected with an outlet of a slurry supply pump 4 through a feed pipe, the other end of the expansion pipe 33 is fixedly connected with one end of a decomposing cavity 35, the other end of the decomposing cavity 35 is fixedly connected with an inlet of a first separator 2, the decomposing cavity 35 is close to an inner wall fixed installation igniter 34 of the expansion pipe 33, a plurality of thermocouples 36 are uniformly installed on the inner wall of the decomposing cavity 35, the necking pipe 31 and the expansion pipe 33 are both in a hollow circular truncated cone structure, the small-diameter ends of the necking pipe 31 and the expansion pipe 33 are respectively and fixedly connected with the throat part 32, the necking pipe 31, the necking pipe 32, the flow rate is increased, the coal water slurry enters from the expansion pipe 33 close to the throat 32, and is atomized by the impact part of the high-speed airflow, so that primary air and the coal water slurry are fully mixed and ignited by the igniter 34, and because the primary air intake is small, the coal water slurry and the primary air are thermally decomposed in the decomposition cavity 35 in an anoxic environment to generate a large amount of reducing gas, and NOx generated during combustion is completely reduced to N2.

The decomposition cavity 35 is of an inclined downward structure, so that the coal water slurry can conveniently flow into the first separator 2, the number of the thermocouples 36 is three, a group of thermocouples 36 are respectively arranged on the inner walls of the front section, the middle section and the rear section of the decomposition cavity 35, and the number of each group of thermocouples 36 is two, so that the temperature in the decomposition cavity 35 can be conveniently and fully detected, and the ignition operation of the igniter 34 can be conveniently controlled.

One side of the insulation can 7 is provided with a sealing plate by a bolt, the air preheater 8 comprises a partition plate 82, the partition plate 82 is fixedly arranged above the inner cavity of the insulation can 7, a plurality of air outlets 83 are uniformly arranged on the partition plate 82, a plurality of guide plates 81 are fixedly arranged on the inner wall of the insulation can 7 at the top of the partition plate 82, two heat exchange tubes 84 are fixedly arranged in the inner cavity of the insulation can 7 at the bottom of the partition plate 82, the two heat exchange tubes 84 are respectively connected with a primary air inlet tube 9 and a secondary air inlet tube 10, spiral fins 85 are fixedly arranged on the outer wall of the heat exchange tubes 84, the tops of the guide plates 81 are all right opposite to the outlets of the smoke delivery tube 6, the bottoms of the guide plates 81 are all inclined towards the side walls at two sides of the insulation can 7, the heat exchange tubes 84 are of a bent snake-shaped structure, finally evenly blow to heat exchange tube 84 through air outlet 83 for heat exchange tube 84 and high temperature flue gas fully contact, the snakelike structure and the helical fin 85 increase of heat exchange tube 84 and flue gas area of contact, the abundant preheating of being convenient for reduces coal slurry pyrolysis and burning power consumption, improves energy utilization, and the heat exchange tube 84 that is close to send tobacco pipe 6 is connected to an air-supply line 9, thereby once the inlet air temperature is higher, the coal slurry thermolysis of being convenient for.

A dust remover 16 is arranged on the smoke exhaust pipe 12 between the heat insulation box 7 and the draught fan 13, so that dust in smoke can be conveniently removed, the draught fan 13 is prevented from being blocked, one-way valves are arranged on the circulating pipes 14 at two ends of the circulating fan 15, and primary air inlet and secondary air inlet are prevented from flowing back to the smoke exhaust pipe 12.

The slurry supply pump 4, the blower 9, the induced draft fan 13 and the circulating fan 15 are all electrically connected with an industrial personal computer 20, a plurality of industrial personal computers 20 are connected with a DSC system 18, the fluidized bed 1, the heat preservation box 7 and the exhaust pipe 12 are internally provided with sensors 19, the sensors 19 are electrically connected with the DSC system 18, the DSC system 18 monitors the bed temperature and the bed pressure in the fluidized bed 1 through the sensors 19, and the oxygen content and the NOx concentration in the heat preservation box 7 and the exhaust pipe 12, so that the power of the slurry supply pump 4, the blower 9, the induced draft fan 13 and the circulating fan 15 is controlled through the industrial personal computer 20, the primary air intake, the secondary air intake and the circulating content of the flue gas are adjusted, the oxygen content in the fluidized bed 1 is accurately.

The working principle is as follows: when the invention is used, the primary air inlet pipe 9 and the secondary air inlet pipe 10 respectively provide air for the decomposition device 3 and the fluidized bed 1 through the blower 11, the primary air inlet provided by the primary air inlet pipe 9 enters the neck shrinkage pipe 31 and is compressed, the flow rate is increased, the coal water slurry enters from the expansion pipe 33 close to the throat neck 32, so that the coal water slurry is impacted by high-speed airflow and is partially atomized, the primary air inlet and the coal water slurry are fully mixed, ignition is carried out through the igniter 34, because the primary air inlet quantity is small, the coal water slurry and the primary air inlet are thermally decomposed in the decomposition cavity 35 under the anoxic environment to generate a large amount of reducing gas containing hydrogen, carbon monoxide, methane and the like, the generated NOx is fully reduced to N2, NOx is primarily reduced, the gas and the coal water slurry are separated through the first separator 2, the gas and the coal water enter the main combustion area 103 to be fully combusted in combination with the secondary air inlet blown out, NOx generated by the main combustion area 103 is subjected to reduction reaction with reducing gas in the reduction area 104 to reduce the concentration of the NOx, the reducing gas is further fully combusted, finally the NOx is completely combusted in the burnout area 105 and the smoke is discharged into the second separator 5, the second separator 5 separates the smoke and sends the smoke into the heat preservation box 7 through the blast pipe 6, air in the primary air inlet pipe 9 and the secondary air inlet pipe 10 is preheated through the air preheater 8 to reduce the energy consumption of coal water slurry pyrolysis and combustion, the energy utilization rate is improved, the smoke is finally discharged through the induced draft fan 13 and the smoke exhaust pipe 12, the DSC system 18 monitors the bed temperature and the bed pressure in the fluidized bed 1 and the oxygen amount and NOx concentration in the heat preservation box 7 and the smoke exhaust pipe 12 through the sensor 19, so that the power of the slurry supply pump 4, the blower 9, the induced draft fan 13 and the circulating fan 15 is controlled through the industrial personal computer 20, the blast volume of the blower 11 is controlled, and the smoke in the smoke exhaust pipe, the flue gas is mixed with the primary air intake and the secondary air intake, so that the oxygen content in the fluidized bed 1 is adjusted, the generation of a large amount of NOx caused by overlarge oxygen content is avoided, and the low-nitrogen combustion performance is improved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.