An improved structure of the secondary combustion chamber of a small domestic waste incinerator

Abstract

The invention discloses an improved structure of a secondary combustion chamber of a small-sized domestic waste incinerator, comprising a feed hopper, a grate assembly and a secondary combustion chamber; an ash collecting hopper is provided on a rear arch, a first opening communicating with a secondary combustion area and a second opening communicating with the ash collecting hopper are provided at the lower end of the secondary combustion chamber; the ash collecting hopper is connected to the rear arch through an ash discharging pipe, and an ash discharging valve is provided on the ash discharging pipe. The invention improves the structure of the secondary combustion chamber of a small-sized domestic waste incinerator, so that the flow in the secondary combustion chamber is more uniform, the 850°C high temperature area fills the entire secondary combustion chamber, the combustion efficiency is improved, the ash cleaning requirements are met, and the overall height of the equipment is reduced. The heating surface is arranged according to the calorific value of the waste, so that the arrangement of the heating surface is more reasonable, the utilization rate of the waste heat is improved, the construction and processing costs are reduced, and low-carbon and environmentally friendly waste incineration treatment is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of incinerators, and in particular to an improved structure of a secondary combustion chamber of a small-sized domestic waste incinerator. Background Art

[0002] In recent years, the market for domestic waste incineration treatment in large and medium-sized cities has gradually become saturated, but the domestic waste treatment capacity at the county level as well as in towns and rural areas is still relatively weak. The reasons for this are mainly due to the small amount of waste, low calorific value, and high construction costs.

[0003] In view of the above difficulties, the structure of small-scale domestic waste incinerators is now optimized, aiming to explore small-scale domestic waste incineration treatment technologies suitable for county and urban areas. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an improved structure of the secondary combustion chamber of a small-scale domestic waste incinerator.

[0005] The technical solution of the present invention is: an improved structure of a secondary combustion chamber of a small-scale domestic waste incinerator, comprising a feed hopper, a grate assembly and a secondary combustion chamber; the grate assembly is located below the secondary combustion chamber, and the feed end of the grate assembly is connected to a pusher, and the discharge end of the grate assembly is connected to a slag hopper and a slag discharger in sequence;

[0006] The secondary combustion chamber located at one side of the feeding end is provided with a front arch, and the secondary combustion chamber located at one side of the discharging end is provided with a rear arch; the feeding hopper is located above the pusher and connected to the front arch; the front arch, the rear arch and the grate assembly constitute a primary combustion area, the front arch, the rear arch and the secondary combustion chamber constitute a secondary combustion area, and an auxiliary burner is provided in the secondary combustion area, an ignition burner is provided at the tail of the rear arch, and secondary air ports are provided on the front arch and the rear arch at the entrance of the secondary combustion area;

[0007] An ash collecting hopper is provided on the rear arch, and a first opening communicating with the secondary combustion area and a second opening communicating with the ash collecting hopper are provided at the lower end of the secondary combustion chamber; the ash collecting hopper is connected to the rear arch through an ash discharge pipe, and an ash discharge valve is provided on the ash discharge pipe.

[0008] Furthermore, the grate assembly is composed of a drying section grate, a combustion section grate and a burnout section grate from the feed end to the discharge end, and the drying section grate and the combustion section grate are arranged obliquely, and the burnout section grate is arranged horizontally;

[0009] The lower ends of the drying section grate, combustion section grate and burnout section grate are correspondingly connected to the drying section air chamber, combustion section air chamber and burnout section air chamber, and an ash discharger for connecting to the slag hopper is provided below the drying section air chamber, combustion section air chamber and burnout section air chamber.

[0010] Description: It is not difficult to see from the current operation examples of domestic waste incineration that the mechanical grate furnace has the advantages of mature technology, easy operation, strong adaptability to garbage, reliable operation, and convenient maintenance. Therefore, the mechanical grate furnace is the only choice for small domestic waste incinerators. The grate of large and medium-sized urban domestic waste incinerators is designed in three sections, including drying section, combustion section, and burnout section. Similarly, small domestic waste incinerators are also designed as drying section, combustion section, and burnout section. The difference is that the three sections of large and medium-sized grate furnaces are all inclined, and the inclination angle is generally 15°~20°. The drying section and combustion section of the miniaturized incinerator grate adopt an inclined design, and the burnout section adopts a horizontal design. Its advantages are that, first, the horizontal arrangement reduces the natural rolling of the ash and slag in the burnout section, reduces dust, and thus reduces the share of fly ash in the flue gas; second, it prolongs the residence time of the burnout material in the furnace and reduces the thermal burning reduction rate of the slag.

[0011] Furthermore, the secondary air inlets of the front arch and the secondary air inlets of the rear arch are arranged alternately; and the wind speed of the secondary air inlets of the rear arch should be higher than the wind speed of the secondary air inlets of the front arch.

[0012] Note: When the secondary air outlets are arranged in a staggered manner, when the wind speeds of the front and rear walls are equal, the cyclone generated by the front wall is much greater than that of the rear wall, and the direction of the flue gas flow will shift toward the rear wall; when the wind speed of the rear wall is greater than that of the front wall, the mainstream of the flue gas deviates to the front wall, the vortex of the front wall is significantly reduced, and the range of the vortex of the rear wall is significantly increased. When the air outlets are arranged in a counter-arrangement, the wind speeds of the front and rear walls are equal, so that the mainstream of the flue gas is located in the center of the furnace outlet, and when the wind speed of the rear wall is higher, the flue gas deviates to the front wall.

[0013] When the secondary air outlets are arranged in a staggered manner, when the wind speed of the rear wall is greater than that of the front wall, the high temperature of the throat flame is located in the center of the flue and the temperature distribution in the flue is relatively uniform. When the secondary air outlets are arranged in a counter-arrangement, if the wind speed of the rear wall is high, it is easy to cause high-temperature corrosion of the front wall. Only when the wind speeds of the front and rear are equal, the high-temperature flue gas is well filled and the temperature is evenly distributed.

[0014] Furthermore, the lower end of the pusher is connected to a leachate collection hopper; and the feed hopper is equipped with a bridge breaking device.

[0015] Description: By setting up a leachate collection hopper, the leachate falling from the pusher can be collected and processed to avoid secondary pollution of the surrounding environment. By setting up a bridge breaking device, the agglomerated garbage can be broken up, thereby improving the processing efficiency of the equipment.

[0016] As a technical solution of the present invention, the side of the secondary combustion chamber close to the feed end is a front wall, and the side close to the discharge end is a rear wall. The lower end of the rear wall of the secondary combustion chamber is connected to the outer end edge of the ash collecting hopper, and the outlet of the secondary combustion chamber is arranged on the rear wall.

[0017] Note: By eliminating the bottom water-cooled wall, the horizontal flue is changed to a three-sided water-cooled wall design, and an ash hopper is arranged at the bottom before the outlet of the secondary combustion chamber to collect particulate matter in the flue gas, thereby reducing the burden on the rear exhaust gas treatment system. By adding an ash hopper, the problem of severe ash accumulation and difficulty in cleaning under actual operating conditions is improved.

[0018] As another technical solution of the present invention, the side of the secondary combustion chamber close to the feed end is a front wall, and the side close to the discharge end is a rear wall. The lower end of the rear wall of the secondary combustion chamber is located above the middle of the ash hopper, and the outlet of the secondary combustion chamber is a second opening. An extension wall is laterally provided at the upper end of the rear wall of the secondary combustion chamber.

[0019] Note: Based on the above solution, the flue gas outlet of the secondary combustion chamber is set at the bottom, and an ash hopper is arranged at the same time, which reduces the flue gas turbulence and increases the heat storage capacity of the secondary combustion chamber, making the flow in the secondary combustion chamber more uniform and meeting the ash cleaning requirements.

[0020] Furthermore, when the calorific value of the garbage is between 1320 and 1370 kcal / kg, a single-sided heating surface is arranged in the secondary combustion chamber; wherein the single-sided heating surface is any one wall;

[0021] When the calorific value of the garbage is between 1370 and 1440 kcal / kg, two or three heating surfaces are arranged in the secondary combustion chamber; wherein the two or three heating surfaces are any two or three walls;

[0022] When the calorific value of the garbage is greater than 1440 kcal / kg, all heating surfaces are arranged in the secondary combustion chamber, including the top wall, front wall, rear wall, left wall and right wall;

[0023] When the calorific value of garbage is lower than 1320kcal / kg, the heating surface can be eliminated in the secondary combustion chamber;

[0024] The heating surface of each wall can be heated partially or entirely.

[0025] Note: By arranging the heating surface according to the calorific value of the garbage, the arrangement of the heating surface can be made more reasonable while meeting the different garbage treatment scales and garbage calorific values, so that all arranged heating surfaces can meet the residence time of 850℃ and 2S, thereby improving the utilization rate of waste heat, reducing construction and processing costs, and realizing low-carbon and environmentally friendly garbage incineration treatment.

[0026] Furthermore, the secondary combustion chamber is provided with a combined water-cooled wall assembly that automatically adjusts the heating surface according to the water pressure, and when a single heating surface is arranged in the secondary combustion chamber, it is the top wall, and when two or three heating surfaces are arranged in the secondary combustion chamber, it is the top wall + any one or two walls;

[0027] The combined water-cooled wall assembly includes a top surface, and a front side surface, a rear side surface, a left side surface, and a right side surface connected to the top surface. A water-cooling pipe of an annular loop is buried inside the top surface, the front side surface, the rear side surface, the left side surface, and the right side surface, and a through hole for setting a rotating shaft is provided at the center of each surface.

[0028] A kinetic energy conduction column is provided on each side of the through hole, the kinetic energy conduction column comprises a kinetic energy conduction column body and a water wheel rotatably arranged in the kinetic energy conduction column body, a liquid inlet is provided on one side of the kinetic energy conduction column body for cooling liquid to enter to drive the water wheel to rotate, one end of the rotating shaft passes through the kinetic energy conduction column body and is fixedly connected to the water wheel, the other end of the rotating shaft is provided with a scraper for cleaning the dust, slag and scale on the water-cooled wall, the interior of the rotating shaft is hollow and communicated with the flow path arranged in the scraper;

[0029] A flow control column and a liquid supply column are sequentially arranged on the top surface of the through hole from top to bottom, a water injection port connected to a liquid pump through a pipeline is arranged on the top of the flow control column, a piston block is arranged in the flow control column, and the upper end of the piston block is connected to the flow control column through a spring, and a first water outlet for communicating with a water cooling pipe in the top surface, a second water outlet for communicating with a water cooling pipe in the right side surface, a third water outlet for communicating with a water cooling pipe in the left side surface, and a fourth water outlet for communicating with water cooling pipes in the front side surface and the rear side surface are sequentially arranged on the side wall of the flow control column from top to bottom.

[0030] The axis of the liquid feeding column is provided with a counterbore, and the side wall of the liquid feeding column is provided with a first drug outlet for communicating with the rotating shaft of the top surface in a rotatable seal, a second drug outlet for communicating with the rotating shaft of the right side surface in a rotatable seal, a third drug outlet for communicating with the rotating shaft of the left side surface in a rotatable seal, and a fourth drug outlet for communicating with the rotating shafts of the front side surface and the rear side surface in a rotatable seal, from top to bottom.

[0031] The lower end of the piston block is connected to a driving column, the inner bottom surface of the flow control column is provided with an annular plate rotatably sleeved with the driving column, at least two groups of airbag rods are provided on the annular plate, an arc-shaped guide groove for rotating the annular plate is provided on the side wall of the driving column, and a guide block slidably connected to the arc-shaped guide groove is provided on the inner ring surface of the annular plate.

[0032] The piston block is built with a liquid bag for adding ethylene glycol to the coolant. The outlet at the upper end of the liquid bag extends out of the upper end of the piston block, and the lower end of the liquid bag extends out of the lower end of the piston block, so as to cooperate with the pushing of the airbag rod to release ethylene glycol into the coolant.

[0033] The lower end of the driving column passes through the inner bottom surface of the flow control column and extends into the countersunk hole. A threaded rod is vertically arranged in the countersunk hole. One end of the threaded rod is threadedly connected to the threaded hole arranged on the bottom surface of the driving column, and the other end is fixedly connected to the rotating shaft.

[0034] A gear is provided on the inner wall of the counterbore corresponding to the first, second, third and fourth outlets, respectively, and a rope groove for arranging a transmission rope is provided in the middle of the gear, and a plug is provided in each of the first, second, third and fourth outlets, one end of the plug is connected to the inner wall of the liquid feeding column through a spring, and one end of the plug is connected to the transmission rope, and a strip-shaped tooth groove meshing with the gear for transmission is provided on the driving column;

[0035] The liquid supply column contains cleaning agent, and the air outlet of the airbag rod is connected with the liquid supply column through a hose with surplus.

[0036] Description: Through the setting of the combined water-cooled wall components, the garbage incineration equipment can have an adjustable heating surface coverage on the basis of a fixed scale. Although the height of the garbage incineration equipment becomes higher, the four modes of single heating surface, 2 or 3 heating surfaces, all heating surfaces or cancellation of heating surfaces can be switched by regulating the hydraulic pressure of the liquid pump, so that dynamic adjustments can be made according to different usage scenarios, so as to call the heating surface in combination with the calorific value of the garbage;

[0037] The structural setting of the combined water-cooled wall component can fully utilize the kinetic energy of the liquid being pumped in, and ethylene glycol can be automatically added to the coolant regularly, so that the coolant is in a long-lasting and efficient use state. At the same time, the cleaning agent can be automatically transported to the corresponding heating surface according to the corresponding mode, so as to cooperate with the scraper to clean the heating surface, so that the combined water-cooled wall component is in a long-lasting and efficient use state.

[0038] Furthermore, the scraper is composed of a main plate and a sub-plate slidingly and sealingly connected to the main plate, one end of the sub-plate is connected to the inner wall of the main plate through a spring, and both the main plate and the sub-plate are provided with spray holes connected to the flow path set in the scraper.

[0039] Note: The above-mentioned scraper structure can be used to scrape and clean the inner wall of a larger range, thereby improving the use effect of each surface.

[0040] The beneficial effects of the present invention are:

[0041] (1) The present invention improves the structure of the secondary combustion chamber of a small-scale domestic waste incinerator, thereby making the flow in the secondary combustion chamber more uniform, and the high-temperature area of ​​850°C fills the entire secondary combustion chamber, thereby improving the combustion efficiency and meeting the ash cleaning requirements.

[0042] (2) The present invention arranges the heating surfaces according to the calorific value of the garbage, so that the arrangement of the heating surfaces can be more reasonable while meeting different garbage treatment scales and garbage calorific values, so that all arranged heating surfaces can meet the residence time of 850°C and 2S, thereby improving the utilization rate of waste heat, reducing construction and treatment costs, and realizing low-carbon and environmentally friendly garbage incineration treatment.

[0043] (3) The present invention can provide the waste incineration equipment with adjustable heating surface coverage on the basis of a fixed scale through the arrangement of combined water-cooled wall components. By utilizing the regulation of the hydraulic pressure of the liquid pump, the four modes of switching between single-sided heating surface, two or three-sided heating surfaces, all heating surfaces or elimination of the heating surface can be switched. Thus, dynamic adjustment can be made according to different usage scenarios, thereby calling the heating surface in combination with the calorific value of the waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator according to Embodiment 1 of the present invention;

[0045] Figure 2 This is a schematic diagram of the improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator according to Embodiment 2 of the present invention;

[0046] Figure 3 It is a schematic diagram of the improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator according to Embodiment 3 of the present invention;

[0047] Figure 4 This is a top view of the combined water-cooled wall assembly of Example 3 of the present invention;

[0048] Figure 5 This is a bottom view of the combined water-cooled wall assembly of Example 3 of the present invention;

[0049] Figure 6 The structure of the flow control column and the liquid supply column of Example 3 of the present invention is shown in FIG. Figure 1 ;

[0050] Figure 7 The structure of the flow control column and the liquid supply column of Example 3 of the present invention is shown in FIG. Figure 2 ;

[0051] Figure 8 Schematic diagram of the internal structure of the flow control column of Example 3 of the present invention;

[0052] Fig. 9 is a schematic diagram of the bottom structure of the piston block of Example 3 of the present invention;

[0053] Fig.10 is a schematic diagram of the structure of a driving column according to Embodiment 3 of the present invention;

[0054] Fig.11is a schematic diagram of the annular plate structure of Example 3 of the present invention;

[0055] Fig.12 Schematic diagram of the structure of the liquid feeding column of Example 3 of the present invention;

[0056] Fig.13 is a schematic diagram of the gear and plug connection structure of Example 3 of the present invention;

[0057] Fig.14 Schematic diagram of the internal structure of the kinetic energy conducting column according to Embodiment 3 of the present invention;

[0058] Fig.15 Schematic diagram of the scraper structure of embodiment 4 of the present invention;

[0059] Fig.16 It is a schematic diagram of the improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator of the comparative example of the present invention;

[0060] Fig.17 It is a model establishment diagram of a comparative example of the present invention;

[0061] Fig.18 2 is a flow field distribution diagram of a comparative example of the present invention;

[0062] Fig.19 It is the temperature field distribution diagram of the comparative example of the present invention;

[0063] Fig. 20 is a model establishment diagram of Example 1 of the present invention;

[0064] Fig.21 is a flow field distribution diagram of Example 1 of the present invention;

[0065] Fig. 22 is a temperature field distribution diagram of Example 1 of the present invention;

[0066] Fig.23 is a model establishment diagram of Example 2 of the present invention;

[0067] Fig.24 is a flow field distribution diagram of Example 2 of the present invention;

[0068] Fig.25 This is a temperature field distribution diagram of Example 2 of the present invention;

[0069] Fig.26 2 is a flow field distribution diagram of air distribution 1 and air distribution 2 of the experimental example of the present invention;

[0070] Fig. 27 1 is a temperature field distribution diagram of air distribution 1 and air distribution 2 of the experimental example of the present invention;

[0071] Fig.28 1 is a flow field distribution diagram of staggered 1, staggered 2 and aligned in an experimental example of the present invention;

[0072] Fig.29 1 is a temperature field distribution diagram of interlaced 1, interlaced 2 and aligned rows of the experimental example of the present invention;

[0073] Fig.30 It is a staggered arrangement diagram of the front arch and rear arch secondary air outlets of the present invention;

[0074] Fig.31 It is a staggered arrangement diagram of the front arch and rear arch secondary air outlets of the present invention;

[0075] Fig.32 It is a parallel arrangement diagram of the front arch and rear arch secondary air outlets of the present invention;

[0076] Among them, 1-feed hopper, 11-pusher, 12-slag hopper, 13-slag discharger, 14-primary combustion area, 15-secondary combustion area, 16-auxiliary burner, 17-ignition burner, 18-ash discharger, 19-leachate collection hopper, 10-bridge breaking device, 2-grate assembly, 21-drying section grate, 22-combustion section grate, 23-burnout section grate, 24-drying section air chamber, 25-combustion section air chamber, 26-burnout section air chamber, 3-secondary combustion chamber, 31-extension wall, 4-front arch, 41-secondary air inlet, 5-rear arch, 6-ash hopper, 61-ash discharge pipe, 7-combined water-cooled wall assembly, 71-top surface, 72-front side surface, 73-rear side surface, 74-left side surface, 7 5-right side, 76-through hole, 77-kinetic energy-conducting column, 78-water wheel, 79-liquid inlet, 70-scraper, 701-main board, 702-sub-board, 8-flow control column, 81-water injection port, 82-piston block, 821-liquid capsule, 83-first water outlet, 84-second water outlet, 85-third water outlet, 86-fourth water outlet, 87-driving column, 871-arc guide groove, 872-strip tooth groove, 88-annular plate, 881-guide block, 89-airbag rod, 9-liquid feeding column, 91-sinking hole, 92-first outlet, 93-second outlet, 94-third outlet, 95-fourth outlet, 96-threaded rod, 97-gear, 971-rope groove, 98-blockage. DETAILED DESCRIPTION

[0077] The present invention is further described in detail below in conjunction with specific implementation methods to better reflect the advantages of the present invention.

[0078] Embodiment 1:

[0079] like Figure 1 As shown, an improved structure of a secondary combustion chamber of a small-scale domestic waste incinerator comprises a feed hopper 1, a grate assembly 2 and a secondary combustion chamber 3; the grate assembly 2 is located below the secondary combustion chamber 3, and a pusher 11 is connected to the feed end of the grate assembly 2, and a slag hopper 12 and a slag discharger 13 are connected to the discharge end of the grate assembly 2 in sequence;

[0080] The grate assembly 2 is composed of a drying section grate 21, a combustion section grate 22 and a burnout section grate 23 from the feeding end to the discharging end, and the drying section grate 21 and the combustion section grate 22 are arranged obliquely, and the burnout section grate 23 is arranged horizontally;

[0081] The lower ends of the drying section grate 21, the combustion section grate 22 and the burnout section grate 23 are connected to the drying section air chamber 24, the combustion section air chamber 25 and the burnout section air chamber 26 respectively, and the ash discharger 18 connected to the slag hopper 12 is provided below the drying section air chamber 24, the combustion section air chamber 25 and the burnout section air chamber 26; the lower end of the pusher 11 is connected to the leachate collecting hopper 19; the feed hopper 1 is provided with a bridge breaking device 10;

[0082] The secondary combustion chamber 3 located at the side of the feeding end is provided with a front arch 4, and the secondary combustion chamber 3 located at the side of the discharging end is provided with a rear arch 5; the feeding hopper 1 is located above the pusher 11 and is connected to the front arch 4; the front arch 4, the rear arch 5 and the grate assembly 2 constitute a primary combustion area 14, the front arch 4, the rear arch 5 and the secondary combustion chamber 3 constitute a secondary combustion area 15, and an auxiliary burner 16 is provided in the secondary combustion area 15, and an ignition burner 17 is provided at the tail of the rear arch 5, and secondary air ports 41 are provided on the front arch 4 and the rear arch 5 at the entrance of the secondary combustion area 15; the secondary air ports of the front arch 4 and the rear arch 5 are arranged alternately, for example: the secondary air ports are provided with 24 and as shown Fig.30 As shown; and the wind speed of the secondary air outlet of the rear arch 5 should be higher than the wind speed of the secondary air outlet of the front arch 4;

[0083] An ash hopper 6 is provided on the rear arch 5, the side of the secondary combustion chamber 3 close to the feed end is a front wall, and the side close to the discharge end is a rear wall, the lower end of the rear wall of the secondary combustion chamber 3 is connected to the outer end edge of the ash hopper 6, and the outlet of the secondary combustion chamber 3 is arranged on the rear wall; the lower end of the secondary combustion chamber 3 is provided with a first opening connected to the secondary combustion area 15, and a second opening connected to the ash hopper 6; the ash hopper 6 is connected to the rear arch 5 through an ash discharge pipe 61, and an ash discharge valve is provided on the ash discharge pipe 61;

[0084] When the calorific value of the garbage is between 1320 and 1370 kcal / kg, a single-sided heating surface is arranged in the secondary combustion chamber 3; the single-sided heating surface is any one wall;

[0085] When the calorific value of the garbage is between 1370 and 1440 kcal / kg, two or three heating surfaces are arranged in the secondary combustion chamber 3; wherein the two or three heating surfaces are any two or three walls, for example, the top wall + the left wall are arranged;

[0086] It is understandable that a wall that is convenient for arranging the heating surface can be selected as the heating surface according to the actual construction situation, and is not limited to the above arrangement;

[0087] When the calorific value of the garbage is greater than 1440 kcal / kg, all heating surfaces are arranged in the secondary combustion chamber 3, including the top wall, front wall, rear wall, left wall and right wall;

[0088] When the calorific value of the garbage is lower than 1320 kcal / kg, the heating surface can be omitted in the secondary combustion chamber 3;

[0089] The heating surface of each wall can be heated partially or entirely;

[0090] It can be understood that the above-mentioned garbage calorific value is an estimated calorific value based on actual garbage treatment expectations, and local heating or whole-surface heating is based on the actual arrangement of water-cooling pipes to make the heating surface circulate locally or throughout the surface, which will not be elaborated here.

[0091] Embodiment 2:

[0092] This embodiment is different from Embodiment 1 in that Figure 2 As shown, the side of the secondary combustion chamber 3 close to the feed end is a front wall, and the side close to the discharge end is a rear wall. The lower end of the rear wall of the secondary combustion chamber 3 is located above the middle of the ash collecting hopper 6, and the outlet of the secondary combustion chamber 3 is a second opening. An extension wall 31 is laterally provided at the upper end of the rear wall of the secondary combustion chamber 3.

[0093] Embodiment 3:

[0094] This embodiment is different from Embodiment 1 in that Figure 3 As shown, the secondary combustion chamber 3 is provided with a combined water-cooled wall assembly 7 that automatically adjusts the heating surface according to the water pressure, and when a single heating surface is arranged in the secondary combustion chamber 3, it is the top wall, and when two or three heating surfaces are arranged in the secondary combustion chamber 3, it is the top wall + any one or two walls. For details, see the method for using the combined water-cooled wall assembly 7 of this embodiment;

[0095] like Figure 4-5 As shown, the combined water-cooled wall assembly 7 includes a top surface 71, and a front side surface 72, a rear side surface 73, a left side surface 74, and a right side surface 75 connected to the top surface 71. The top surface 71, the front side surface 72, the rear side surface 73, the left side surface 74, and the right side surface 75 are all embedded with a ring-shaped loop of water-cooling pipes (not shown in the figure), and the center of each surface is provided with a through hole 76 for setting a rotating shaft.

[0096] like Figure 5As shown, a kinetic energy conduction column is provided on each side of the through hole 76, and the kinetic energy conduction column includes a kinetic energy conduction column 77 and a water wheel 78 rotatably arranged in the kinetic energy conduction column 77. A liquid inlet 79 is provided on one side of the kinetic energy conduction column 77 for the coolant to enter to drive the water wheel 78 to rotate. One end of the rotating shaft passes through the kinetic energy conduction column 77 and is fixedly connected to the water wheel 78. The other end of the rotating shaft is provided with a scraper 70 for cleaning the dust, slag and scale on the water-cooled wall. The interior of the rotating shaft is hollow and communicates with the flow path arranged in the scraper 70.

[0097] like Figure 4 , 6 -11, a flow control column 8 and a liquid supply column 9 are sequentially arranged on the top surface of the through hole 76 from top to bottom, a water injection port 81 connected to a liquid pump through a pipeline is arranged on the top of the flow control column 8, a piston block 82 is arranged in the flow control column 8, and the upper end of the piston block 82 is connected to the flow control column 8 through a spring, and a first water outlet 83 for communicating with a water cooling pipe in the top surface, a second water outlet 84 for communicating with a water cooling pipe in the right side surface, a third water outlet 85 for communicating with a water cooling pipe in the left side surface, and a fourth water outlet 86 for communicating with water cooling pipes in the front side surface and the rear side surface are sequentially arranged on the side wall of the flow control column 8 from top to bottom,

[0098] like Figure 12-14 As shown, a counterbore 91 is provided at the axis of the liquid feeding column 9, and the side wall of the liquid feeding column 9 is provided with a first drug outlet 92 for communicating with the rotating shaft of the top surface in a sealing manner, a second drug outlet 93 for communicating with the rotating shaft of the right side surface in a sealing manner, a third drug outlet 94 for communicating with the rotating shaft of the left side surface in a sealing manner, and a fourth drug outlet 95 for communicating with the rotating shaft of the front side surface and the rear side surface in a sealing manner.

[0099] like Fig.10 As shown, the lower end of the piston block 82 is connected to a driving column 87, the inner bottom surface of the flow control column 8 is provided with an annular plate 88 rotatably sleeved with the driving column 87, at least two groups of airbag rods 89 are provided on the annular plate 88, and an arc guide groove 871 for rotating the annular plate 88 is provided on the side wall of the driving column 87, and a guide block 881 slidably connected to the arc guide groove 871 is provided on the inner ring surface of the annular plate 88.

[0100] like Fig. 9 As shown, the piston block 82 has a built-in liquid capsule 821 for adding ethylene glycol to the coolant. The outlet at the upper end of the liquid capsule 821 extends out of the upper end of the piston block 82, and the lower end of the liquid capsule 821 extends out of the lower end of the piston block 82, so as to cooperate with the pushing of the airbag rod 89 to release ethylene glycol into the coolant.

[0101] It is understandable that the coolant is a commercially available product and the additives are not limited to ethylene glycol as a supplementary ingredient;

[0102] like Fig.12 As shown, the lower end of the driving column 87 passes through the inner bottom surface of the flow control column 8 and extends into the counterbore 91. A threaded rod 96 is vertically arranged in the counterbore 91. One end of the threaded rod 96 is threadedly connected to the threaded hole arranged on the bottom surface of the driving column 87, and the other end is fixedly connected to the rotating shaft. A gear 97 is respectively arranged on the inner wall of the counterbore 91 corresponding to the positions of the first, second, third and fourth outlets 92, 93, 94 and 95. A rope groove 971 for arranging a transmission rope is arranged in the middle of the gear 97. A plug 98 is arranged in the first, second, third and fourth outlets 92, 93, 94 and 95. One end of the plug 98 is connected to the inner wall of the liquid feeding column 9 through a spring, and one end of the plug 98 is connected to the transmission rope. The driving column 87 is provided with a strip tooth groove 872 meshing with the gear 97 for transmission.

[0103] It can be understood that, since the bar-shaped tooth groove 872 continuously moves downward, the gears 97 of the first dosage outlet 92 will continuously rotate, and therefore the transmission rope should have a certain elasticity so that the movement margin can be compensated when the gear 97 rotates excessively, so as to prevent the transmission rope from being torn or the gear 97 from being unable to rotate;

[0104] The liquid supply column 9 contains cleaning agent, and the air outlet of the airbag rod 89 is connected to the liquid supply column 9 through a hose with a surplus;

[0105] It can be understood that the hose with a surplus is one that can meet the rotational travel of the annular plate 88 during reciprocating rotation to prevent the hose from being torn off, and a commercially available one-way valve is provided at the connection between the hose and the liquid supply column 9.

[0106] The method of using the combined water-cooled wall assembly 7 is as follows:

[0107] Connect the outlet of the liquid pump to the water injection port 81 through a pipeline, connect the drainage ports on each surface to the inlet of the liquid pump through pipelines, and then calculate the calorific value of the garbage. According to the calorific value of the garbage being less than 1320 kcal / kg, the calorific value of the garbage being between 1320 and 1370 kcal / kg, the calorific value of the garbage being between 1370 and 1440 kcal / kg, and the calorific value of the garbage being greater than 1440 kcal / kg, the four-speed pump hydraulic pressure of the liquid pump is preset, and the spring strength of the spring connecting the piston block 82 and the flow control column 8 is set at the same time;

[0108] The first-stage pump hydraulic pressure of the starting liquid pump makes the piston block 82 in a position state where the first water outlet 83 is exposed; the second-stage pump hydraulic pressure of the starting liquid pump makes the piston block 82 in a position state where the second water outlet 84 is exposed; the third-stage pump hydraulic pressure of the starting liquid pump makes the piston block 82 in a position state where the third water outlet 85 is exposed; the fourth-stage pump hydraulic pressure of the starting liquid pump makes the piston block 82 in a position state where the fourth water outlet 86 is exposed;

[0109] At the same time, the piston block 82 drives the driving column 87 to move downward during its movement. Under the action of the arc-shaped guide groove 871 and the guide block 881, the annular plate 88 rotates. During the rotation of the annular plate 88, the airbag rod 89 pushes the liquid capsule 821 so that the ethylene glycol in the liquid capsule 821 is squeezed out into the coolant through the outlet. At the same time, the piston block 82 presses the airbag rod 89 downward so that the airbag rod 89 inflates the airbag in the liquid supply column 9, thereby keeping the liquid supply column 9 in a pressurized state for a long time.

[0110] For the top surface: after the driving column 87 extends into the counterbore 91, the strip-shaped tooth groove 872 is meshed with the gear 97, so that the transmission rope is tightened to pull the plug 98 of the first agent outlet 92 toward the side of the gear 97, so that the first agent outlet 92 is exposed, and the cleaning agent enters the scraper through the rotating shaft and the flow path and is sprayed onto the surface. At the same time, under the threaded cooperation between the threaded rod 96 and the driving column 87, the threaded rod 96 rotates and drives the rotating shaft to rotate, and the scraper uses the cleaning agent to efficiently scrape and clean the opposite side;

[0111] For each side surface, the principle is basically the same as that of the top surface, except that when the coolant flows into each kinetic energy conducting column 77, the coolant drives the water wheel 78 to rotate, and the scraper uses the cleaning agent to efficiently scrape and clean the opposite surface.

[0112] Embodiment 4:

[0113] This embodiment is different from Embodiment 3 in that Fig.15 As shown, the scraper 70 is composed of a main plate 701 and a sub-plate 702 which is slidingly and sealingly connected to the main plate 701. One end of the sub-plate 702 is connected to the inner wall of the main plate 701 through a spring, and both the main plate 701 and the sub-plate 702 are provided with spray holes which are connected to the flow path set in the scraper 70.

[0114] The method of using the scraper 70 is as follows:

[0115] When the scraper 70 moves to the vertical section of the combined water-cooled wall assembly, the auxiliary plate 702 partially shrinks into the main plate 701. When the scraper 70 moves to the horizontal section of the combined water-cooled wall assembly, the auxiliary plate 702 recovers under the action of the spring, thereby extending the scraping area.

[0116] Experimental example:

[0117] The design of the secondary combustion chamber structure needs to fully consider the requirements of complete combustion, heat energy utilization, environmental protection, etc., and must follow the basic principles of 3T+E and meet the requirements of the "Standard for Pollution Control of Municipal Waste Incineration" (GB 18485-2014). Taking an incinerator with a daily processing capacity of 200t / d as an example, the incinerator structure is designed and calculated.

[0118] The composition of domestic waste in a county in southwest my country was selected as the basis for calculation.

[0119] Table 1 Analysis of domestic waste industry

[0120]

[0121] Table 2 Element analysis of domestic waste

[0122]

[0123] Table 3 Furnace structure characteristics calculation table

[0124]

[0125] In order to verify the effect of the improved structural design of the secondary combustion chamber, the following simulation test is carried out by taking Example 1 and Example 2 as examples, and a control example is set at the same time: the flue of the secondary combustion chamber is arranged horizontally, the flue gas is discharged directly, and the horizontal flue is arranged with commercially available water-cooled walls, such as Fig.16 shown.

[0126] Comparison example: Create a grid model in the software according to the scheme diagram, such as Fig.17 The simulation results are shown in Table 4, and the flow field and temperature field distribution are shown in Fig.18 , Fig.19 shown.

[0127] Table 4 Comparative example simulation data

[0128]

[0129]

[0130] from Fig.18 It can be seen that the flow field of the model at the bend is more complicated, and there is a vortex at the upper left corner and the lower right corner of the flue bend. From the perspective of heat transfer, these two vortices can isolate the high-temperature flue gas from direct contact with the wall and prevent high temperature from corroding the wall. After the airflow enters the transverse flue, the temperature is close to 850 degrees. The vortex at the bottom of the transverse flue forms a layer of thermal resistance between the high-temperature flue gas and the wall. The flue gas close to the wall cannot absorb the heat from the mainstream, so the temperature is lower than 850℃, which runs counter to the dioxin control requirement - "the temperature stays above 850 for more than 2s".

[0131] Example 1: Based on the design of the control example, the bottom water-cooled wall is removed, the horizontal flue is changed to a three-sided water-cooled wall design, and an ash hopper is arranged at the bottom before the outlet of the secondary combustion chamber to collect particulate matter in the flue gas, thereby reducing the burden on the rear exhaust gas treatment system. Figure 1 shown.

[0132] According to the scheme diagram, a grid model is established in the software, such as Fig. 20The simulation results are shown in Table 5, and the flow field and temperature field distribution are shown in Fig.21 , Fig. 22 shown.

[0133] Table 5 Simulation data of Example 1

[0134]

[0135] from Fig.21 It can be seen from the figure that after adding the bottom ash hopper in Scheme 2, the flow field changes significantly. A larger and more complete cyclone is generated at the ash hopper. The ash hopper and the lower wall of the flue are set as adiabatic walls. The existence of the vortex causes part of the high-temperature flue gas to flow back and mix with the low-temperature flue gas on the lower wall. Fig. 22 It can be seen from the figure that the temperature in the front section of the lower wall is still below 850 degrees, while in the second half the temperature is slightly higher due to the mixing of high-temperature flue gas.

[0136] Example 2: Based on the design of Example 1, the flue gas outlet of the secondary combustion chamber is set at the bottom, and an ash hopper is arranged at the same time to reduce flue gas turbulence and increase the heat storage capacity of the secondary combustion chamber. Figure 2 shown.

[0137] According to the scheme diagram, a grid model is established in the software, such as Fig.23 The simulation results are shown in Table 6, and the flow field and temperature field distribution are shown in Fig.24 , Fig.25 shown.

[0138] Table 6 Simulation data of Example 2

[0139]

[0140] like Fig.24 As shown, in Example 2, the airflow direction is changed so that the flue gas turns downward when it hits the ash hopper, which reduces the vortex size of the lower wall to a certain extent, and the heat transfer path between the high-temperature mainstream flue gas and the lower wall is shorter, so that the low-temperature flue gas on the lower wall absorbs heat faster, thereby Fig.25 It can be seen from the figure that within the entire first flue, flue gas with a temperature above 850 degrees fills the entire cavity, which is the most ideal temperature.

[0141] Conclusion: The simulation experiment shows that although the flow field and temperature field of the control example are uniform, the ash accumulation is serious under the actual operating conditions, the cleaning of this structure is more difficult, and the flue gas filling degree inside the flue is not good. The flue gas temperature on the lower wall of the transverse flue cannot reach 850 degrees, which cannot meet the national standard for controlling dioxin temperature requirements; Example 1 adds an ash hopper on the basis of the control example, and changes the lower wall to an insulated wall, but there is a huge vortex above the ash hopper, occupying half of the flue cross-section. The vortex promotes the reflux of high-temperature flue gas, which alleviates the phenomenon of too low flue gas on the lower wall to a certain extent, but there is still an area on the lower wall where the airflow temperature is lower than 850 degrees; Example 2 is further optimized on the basis of Example 1, and the airflow direction is changed. It can be seen from the simulation effect that the 850℃ high temperature area fills the entire secondary combustion chamber, and the flow in the secondary combustion chamber is relatively uniform, and the cleaning requirements can be met at the same time.

[0142] At the same time, in order to test the effect of the secondary air inlet setting on the improved structural design of the secondary combustion chamber, the test is as follows:

[0143] Table 7 Exhaust ratio of grate assembly

[0144]

[0145] Table 8 Wind speed of secondary air duct of front arch and rear arch

[0146]

[0147] Table 9 Exhaust ratio of secondary air duct layout of front arch and rear arch

[0148]

[0149] Table 10 Comparison of secondary air duct layout between front arch and rear arch

[0150]

[0151] like Fig.30 As shown, it is the layout diagram of the front arch and rear arch secondary air outlets of the above-mentioned staggered 1; Fig.31 As shown, it is the layout diagram of the front arch and rear arch secondary air outlets of the above-mentioned staggered 2; Fig.32 The figure shows the arrangement diagram of the secondary air outlets of the front arch and the rear arch in the above row;

[0152] From the above Tables 7 to 10 and Figure 26-Figure 29 When the secondary air tuyere is staggered, when the wind speed of the front and rear walls is equal, the cyclone generated by the front wall is much greater than that of the rear wall, and the flue gas flow direction will shift to the rear wall; when the wind speed of the rear wall is greater than that of the front wall, the flue gas mainstream deviates to the front wall, the vortex of the front wall is significantly reduced, and the vortex range of the rear wall is significantly increased. When the tuyere is arranged in a counter-arrangement, the wind speed of the front and rear walls is equal, so that the flue gas mainstream is located in the center of the furnace outlet, and when the wind speed of the rear wall is higher, the flue gas deviates to the front wall.

[0153] When the secondary air outlets are staggered, the wind speed of the rear wall is greater than that of the front wall, the high temperature of the throat flame is located in the center of the flue, and the temperature distribution in the flue is relatively uniform. When the secondary air outlets are arranged in a staggered manner, if the wind speed of the rear wall is high, it is easy to cause high-temperature corrosion of the front wall. Only when the wind speeds of the front and rear walls are equal, the high-temperature flue gas is well filled and the temperature is evenly distributed. By comparing the temperature range greater than 850℃, the staggered arrangement and the wind speed of the rear wall greater than the wind speed of the front wall are the best secondary air outlet arrangement methods.

Claims

1. An improved structure of a secondary combustion chamber of a small-scale domestic waste incinerator, comprising a feed hopper (1), a grate assembly (2) and a secondary combustion chamber (3); the grate assembly (2) is located below the secondary combustion chamber (3), and the feed end of the grate assembly (2) is connected to a pusher (11), and the discharge end of the grate assembly (2) is connected to a slag hopper (12) and a slag discharger (13) in sequence; The secondary combustion chamber (3) located at the side of the feeding end is provided with a front arch (4), and the secondary combustion chamber (3) located at the side of the discharging end is provided with a rear arch (5); the feeding hopper (1) is located above the pusher (11) and is connected to the front arch (4); the front arch (4), the rear arch (5) and the grate assembly (2) constitute a primary combustion area (14), the front arch (4), the rear arch (5) and the secondary combustion chamber (3) constitute a secondary combustion area (15), and an auxiliary burner (16) is provided in the secondary combustion area (15), and an ignition burner (17) is provided at the tail of the rear arch (5), and secondary air ports (41) are provided on the front arch (4) and the rear arch (5) at the entrance of the secondary combustion area (15); It is characterized in that The rear arch (5) is provided with an ash collecting hopper (6); the lower end of the secondary combustion chamber (3) is provided with a first opening communicating with the secondary combustion area (15), and a second opening communicating with the ash collecting hopper (6); the ash collecting hopper (6) is connected to the rear arch (5) via an ash discharging pipe (61), and an ash discharging valve is provided on the ash discharging pipe (61); When the calorific value of the garbage is between 1320 and 1370 kcal / kg, a single-sided heating surface is arranged in the secondary combustion chamber (3); wherein the single-sided heating surface is any one wall; When the calorific value of the garbage is between 1370 and 1440 kcal / kg, two or three heating surfaces are arranged in the secondary combustion chamber (3); wherein the two or three heating surfaces are any two or three walls; When the calorific value of the garbage is greater than 1440 kcal / kg, all heating surfaces are arranged in the secondary combustion chamber (3), including the top wall, the front wall, the rear wall, the left wall and the right wall; When the calorific value of the garbage is lower than 1320 kcal / kg, the heating surface in the secondary combustion chamber (3) can be omitted; The heating surface of each wall can be heated partially or entirely; The secondary combustion chamber (3) is provided with a combined water-cooled wall assembly (7) for automatically adjusting the heating surface according to the water pressure, and when a single heating surface is arranged in the secondary combustion chamber (3), it is a top wall, and when two or three heating surfaces are arranged in the secondary combustion chamber (3), it is a top wall + any one or two walls; The combined water-cooled wall assembly (7) comprises a top surface (71), and a front side surface (72), a rear side surface (73), a left side surface (74), and a right side surface (75) connected to the top surface (71) on all sides; a water-cooling pipe of an annular loop is embedded in the top surface (71), the front side surface (72), the rear side surface (73), the left side surface (74), and the right side surface (75); and a through hole (76) for setting a rotating shaft is provided at the center of each surface. A kinetic energy deflection column is provided on each side of the through hole (76), the kinetic energy deflection column comprising a kinetic energy deflection column body (77) and a water wheel (78) rotatably arranged in the kinetic energy deflection column body (77), a liquid inlet (79) for coolant to enter to drive the water wheel (78) to rotate is provided on one side of the kinetic energy deflection column body (77), one end of the rotating shaft passes through the kinetic energy deflection column body (77) and is fixedly connected to the water wheel (78), the other end of the rotating shaft is provided with a scraper (70) for cleaning dust, slag and scale deposited on the water-cooled wall, the interior of the rotating shaft is hollow and communicates with a flow path arranged in the scraper (70); A flow control column (8) and a liquid supply column (9) are sequentially arranged on the top surface of the through hole (76) from top to bottom, a water injection port (81) connected to a liquid pump through a pipeline is arranged on the top of the flow control column (8), a piston block (82) is arranged inside the flow control column (8), and the upper end of the piston block (82) is connected to the flow control column (8) through a spring, and a first water outlet (83) for communicating with a water cooling pipe in the top surface, a second water outlet (84) for communicating with a water cooling pipe in the right side surface, a third water outlet (85) for communicating with a water cooling pipe in the left side surface, and a fourth water outlet (86) for communicating with water cooling pipes in the front side surface and the rear side surface are sequentially arranged on the side wall of the flow control column (8) from top to bottom, The axis of the liquid feeding column (9) is provided with a counterbore (91), and the side wall of the liquid feeding column (9) is provided with a first drug outlet (92) for communicating with the rotating shaft of the top surface in a rotatable seal, a second drug outlet (93) for communicating with the rotating shaft of the right side surface in a rotatable seal, a third drug outlet (94) for communicating with the rotating shaft of the left side surface in a rotatable seal, and a fourth drug outlet (95) for communicating with the rotating shafts of the front side surface and the rear side surface in a rotatable seal, from top to bottom. The lower end of the piston block (82) is connected to a driving column (87); the inner bottom surface of the flow control column (8) is provided with an annular plate (88) rotatably sleeved with the driving column (87); at least two groups of airbag rods (89) are provided on the annular plate (88); an arc-shaped guide groove (871) for rotating the annular plate (88) is provided on the side wall of the driving column (87); a guide block (881) slidably connected to the arc-shaped guide groove (871) is provided on the inner annular surface of the annular plate (88); The piston block (82) is internally provided with a liquid capsule (821) for adding ethylene glycol to the coolant. The outlet at the upper end of the liquid capsule (821) extends out of the upper end of the piston block (82), and the lower end of the liquid capsule (821) extends out of the lower end of the piston block (82), so as to cooperate with the pushing of the airbag rod (89) to release ethylene glycol into the coolant. The lower end of the driving column (87) passes through the inner bottom surface of the flow control column (8) and extends into the countersunk hole (91). A threaded rod (96) is vertically arranged in the countersunk hole (91). One end of the threaded rod (96) is threadedly connected to a threaded hole arranged on the bottom surface of the driving column (87), and the other end is fixedly connected to the rotating shaft. A gear (97) is provided on the inner wall of the counterbore (91) corresponding to the first drug outlet (92), the second drug outlet (93), the third drug outlet (94) and the fourth drug outlet (95), respectively; a rope groove (971) for arranging a transmission rope is provided in the middle of the gear (97); and a plug (98) is provided in each of the first drug outlet (92), the second drug outlet (93), the third drug outlet (94) and the fourth drug outlet (95), one end of the plug (98) is connected to the inner wall of the liquid feeding column (9) through a spring, and one end of the plug (98) is connected to the transmission rope; and a strip-shaped tooth groove (872) meshing with the gear (97) for transmission is provided on the driving column (87); The liquid supply column (9) contains cleaning agent, and the air outlet of the airbag rod (89) is connected to the liquid supply column (9) through a hose with a surplus.

2. The improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator as claimed in claim 1 is characterized in that: The grate assembly (2) is composed of a drying section grate (21), a combustion section grate (22) and a burnout section grate (23) in sequence from the feeding end to the discharging end, and the drying section grate (21) and the combustion section grate (22) are arranged obliquely, and the burnout section grate (23) is arranged horizontally; The lower ends of the drying section grate (21), the combustion section grate (22) and the burnout section grate (23) are connected to the drying section air chamber (24), the combustion section air chamber (25) and the burnout section air chamber (26) respectively, and an ash discharger (18) for connecting to the slag hopper (12) is provided below the drying section air chamber (24), the combustion section air chamber (25) and the burnout section air chamber (26).

3. The improved structure of the secondary combustion chamber of a small-scale domestic waste incinerator as claimed in claim 1 is characterized in that: Secondary air ports (41) are provided on the front arch (4) and the rear arch (5) located at the entrance of the secondary combustion area (15), and the secondary air ports of the front arch (4) and the secondary air ports of the rear arch (5) are arranged alternately; and the wind speed of the secondary air ports of the rear arch (5) should be higher than the wind speed of the secondary air ports of the front arch (4).

4. The improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator as claimed in claim 1, characterized in that: The lower end of the pusher (11) is connected to a leachate collecting hopper (19); and the feed hopper (1) is internally provided with a bridge breaking device (10).

5. The improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator as claimed in claim 1, characterized in that: The side of the secondary combustion chamber (3) close to the feeding end is a front wall, and the side close to the discharging end is a rear wall. The lower end of the rear wall of the secondary combustion chamber (3) is connected to the outer end edge of the ash collecting hopper (6), and the outlet of the secondary combustion chamber (3) is arranged on the rear wall.

6. The improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator as claimed in claim 5, characterized in that: The lower end of the rear wall of the secondary combustion chamber (3) is located above the middle of the ash collecting hopper (6), and the outlet of the secondary combustion chamber (3) is a second opening. An extension wall (31) is laterally arranged at the upper end of the rear wall of the secondary combustion chamber (3).

7. The improved structure of the secondary combustion chamber of a small-sized domestic waste incinerator as claimed in claim 1, characterized in that: The scraper (70) is composed of a main plate (701) and a sub-plate (702) connected to the main plate (701) in a sliding and sealing manner. One end of the sub-plate (702) is connected to the inner wall of the main plate (701) via a spring, and both the main plate (701) and the sub-plate (702) are provided with spray holes that are connected to a flow path provided in the scraper (70).

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