CN209819528U - Biomass boiler multistage air distribution system capable of reducing nitrogen oxides - Google Patents

Abstract

The utility model relates to a biomass boiler multi-stage air distribution system capable of reducing nitrogen oxides, which belongs to the technical field of boiler environmental protection. The primary air system is located at the lower part of the grate, the flue gas circulation system is located on one side of the primary air system, the secondary air system and the tertiary air system are respectively located at the upturned places of the front and rear arches; the primary air system includes fans, main pipes, branch Pipeline, boiler air outlet, and nine independent air chambers B, the fan is connected to the boiler air outlet through the main pipe and branch pipes, and the fan sends external air to the main pipe through the air pipe, and then sent to the nine air chambers by the main pipe. The branch pipes of each air chamber B, and the branch pipes control the air supply volume of the pipes through the air volume automatic adjustment valves of each air chamber B. The advantages are: novel conception, simple structure, safe and convenient use. Reduce nitrogen oxide emissions from biomass boilers, energy saving and environmental protection, and strong practicability.

Description

Biomass boiler multi-stage air distribution system with reduced nitrogen oxides

technical field

The utility model relates to the technical field of boiler environmental protection, in particular to a multi-stage air distribution system for a biomass boiler, in particular to a multi-stage air distribution system for a biomass boiler capable of reducing nitrogen oxides.

Background technique

At present, biomass boilers are recognized by more and more energy-using customers both in terms of environmental protection and economical aspects. As the fourth largest energy pool, biomass has its unique advantages in replacing coal burning. Biomass fuel has the characteristics of low sulfur, low nitrogen, high volatile content, easy to ignite, and zero carbon dioxide emissions. The nitrogen oxides in the flue gas are also mainly from the generation of thermal nitrogen oxides during the combustion process. Therefore, controlling the combustion temperature of the furnace can meet the environmental protection emission requirements of most places without installing sulfur removal and denitrification equipment. Economical and environmentally friendly.

To control the temperature of the furnace, reasonable air distribution is the key. At present, the air distribution of biomass boilers is mainly to provide air supply at the feed inlet, which makes the air supply uneven, and the local temperature is too high, resulting in incomplete combustion of fuel, and the generation of thermal nitrogen oxides, which makes the nitrogen oxides in the flue gas Exceeded the standard.

Contents of the invention

The purpose of the utility model is to provide a biomass boiler multi-stage air distribution system with reduced nitrogen oxides, which solves the above-mentioned problems in the prior art. The utility model combusts the biomass fuel in sections in the furnace, reduces the temperature in the furnace in the combustion area, reduces the generation of thermal nitrogen oxides, and solves the problem of high nitrogen oxide emissions from the biomass boiler.

Above-mentioned purpose of the utility model is realized through the following technical solutions:

Biomass boiler multi-stage air distribution system with nitrogen oxide reduction, including primary air system, flue gas circulation system, secondary air system and tertiary air system, the primary air system is located at the bottom of the grate, and the flue gas circulation system is located at the On one side of the air system, the secondary air system and the tertiary air system are respectively located at the upturned places of the front arch 5 and the rear arch 6;

The primary air system includes a fan 8, a main duct 11, a branch duct 12, a boiler air outlet 13, and nine mutually independent air chambers B2, and the fan 8 is connected to the boiler air outlet 13 through the main duct 11 and the branch duct 12 , the fan 8 transports the external air to the main duct 11 through the air duct 10, and then the main duct 11 transports it to the branch ducts 12 of the nine air chambers B2, and the branch ducts 12 control the pipeline supply through the air volume automatic adjustment valve 14 of each air chamber B air volume.

The flue gas circulation system includes a circulation fan 7, a flue gas pipe 9, a flue gas circulation pipe 15 and an independent air chamber A1, the flue gas pipe 9 is connected to the inlet of the circulation fan, and the outlet of the circulation fan passes through the flue gas circulation pipe 15. The air volume automatic regulating valve 14 is connected to the boiler air supply port 13 in the air chamber A1; the air chamber A1 is located beside the feeding place of the grate shell, paralleled with the nine air chambers B2 in the primary air system, and evenly distributed On both sides of the grate shell; the circulation fan 7 sends the flue gas processed by the dust collector into the flue gas circulation pipe 15 through the flue gas pipe 9, and the flue gas circulation pipe 15 transports the flue gas to the air chamber A1, and automatically passes through the air volume A regulator valve 14 controls the required air supply.

Described secondary air system comprises front arch air delivery duct 16, front arch air supply duct 17, front arch air supply duct 3, and front arch air supply duct 3 is connected to front arch air delivery duct 16 at front arch air delivery duct 17. The front arch air duct 16 is connected to the main duct 11; the front arch air supply pipe 3 is located at the upturned position of the front arch 5 of the boiler, and the air supply direction is perpendicular to the flue gas flow direction in the lower part of the furnace.

The tertiary air system comprises a rear arch air delivery duct 18, a rear arch air supply duct 19, and a rear arch air delivery duct 4, and the rear arch air delivery duct 4 is connected to the rear arch air delivery duct 18 at the rear arch air delivery duct 19 , the rear arch air duct 18 is connected to the main duct 11; the rear arch air supply pipe 4 is turned out on the rear arch 6 of the boiler, and the air supply direction is perpendicular to the flue gas flow direction on the upper part of the furnace.

The beneficial effects of the utility model are: novel conception, simple structure, energy saving and environmental protection, and safe and convenient use. The primary air system and flue gas circulation system mainly burn carbon in the grate, and the secondary and tertiary air systems mainly burn volatile matter. The high volatile biomass fuel is burned in stages to reduce the furnace temperature in the combustion area. Reduces the formation of thermal nitrogen oxides. The flue gas recirculation system reduces the oxygen content in the flue gas, and on the other hand reduces the conversion value of nitrogen oxides. Thus reducing the emission of nitrogen oxides as a whole. Strong practicality.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the utility model and constitute a part of the application. The schematic examples and descriptions of the utility model are used to explain the utility model and do not constitute improper limitations to the utility model.

Fig. 1 is the front view of the boiler with air distribution structure of the present utility model;

Fig. 2 is the primary air system diagram of the utility model;

Fig. 3 is the flue gas circulation system figure of the utility model;

Fig. 4 is the secondary air system diagram of the utility model;

Fig. 5 is the tertiary air system diagram of the utility model.

In the figure: 1. Air chamber A; 2. Air chamber B; 3. Front arch air supply pipe; 4. Back arch air supply pipe; 5. Front arch; 6. Back arch; 7. Circulation fan; 8. Fan; 9. Flue gas circulation pipe; 10. Air pipe; 11. Main pipe; 12. Branch pipe; 13. Boiler air outlet; 14. Automatic air volume control valve; 15. Flue gas circulation pipe; 16. Front arch air supply pipe; 17. Front arch air supply port; 18, rear arch air supply duct; 19, rear arch air supply port.

Detailed ways

Further illustrate the detailed content of the utility model and its specific implementation below in conjunction with accompanying drawing.

Referring to Fig. 1 to Fig. 5, the biomass boiler multi-stage air distribution system with nitrogen oxide reduction of the utility model includes a primary air system, a flue gas circulation system, a secondary air system and a tertiary air system. The air system is located at the lower part of the grate, the flue gas circulation system is located on one side of the primary air system, the secondary air system and the tertiary air system are respectively located at the upturned places of the front arch 5 and the rear arch 6;

Referring to Fig. 1 and shown in Fig. 2, described primary air system comprises fan 8, main duct 11, branch duct 12, boiler air outlet 13, and nine mutually independent air chambers B2, and described fan 8 passes through main duct 11, The branch pipe 12 is connected with the boiler air outlet 13, the main pipe is provided with a pressure valve and a check valve, and the branch pipe connected with each air chamber is provided with a flow regulating valve. The air supply port of the boiler is located at the lower part of the grate and consists of nine air chambers B, which are evenly distributed on both sides of the grate shell. The air chamber B sends the outdoor air into the air outlet by the fan. With the operation of the grate, the combustion state of the fuel is different, and the air volume required by each air chamber is adjusted by the frequency conversion fan. The fan 8 continuously transports the external air to the main duct 11 through the air duct 10, and then transports it to the branch ducts 12 of the nine air chambers B2 by the main duct 11. Supply air volume and send reasonable air volume to nine air chambers B2. The fuel entering the grate at the same time, with the operation of the grate, the degree of combustion of the fuel is different in the combustion area corresponding to each air chamber, and the air volume is controlled by partition to make the fuel fully burn and improve the thermal efficiency of the boiler.

1 and 3, the flue gas circulation system includes a circulation fan 7, a flue gas duct 9, a flue gas circulation duct 15 and an independent air chamber A1, and the flue gas duct 9 is connected to the inlet of the circulation fan , the outlet of the circulating fan is connected to the boiler air supply port 13 in the air chamber A1 through the flue gas circulation pipe 15 and the automatic air volume control valve 14; The nine air chambers B2 are arranged side by side, and are evenly distributed on both sides of the grate shell. The main pipe is equipped with a pressure valve and a check valve, and the branch pipe connected to the air chamber is equipped with a flow regulating valve. The wind source comes from the flue gas produced by the internal combustion of the boiler after being treated by the dust collector. It can provide a relatively stable oxygen supply environment for the biomass fuel in the initial combustion stage, and at the same time reduce the oxygen content in the flue gas. The circulation fan 7 sends the flue gas processed by the dust collector into the flue gas circulation pipe 15 through the flue gas pipe 9, and the flue gas circulation pipe 15 transports the flue gas to the air chamber A1, and controls the required air supply through the air volume automatic adjustment valve 14 amount; while providing air for fuel combustion in the boiler, it reduces the oxygen content in the flue gas and controls the production of thermal nitrogen oxides.

The fixed carbon in biomass is mainly burned on the grate under the joint action of the primary air system and the flue gas circulation system. Depending on the direction of the grate, the degree of combustion of the fuel is different, and the amount of oxygen required is different. Through the automatic adjustment of the air volume of the independent air chamber, the air volume supply is reasonably controlled.

Referring to Figures 1 and 4, the secondary air system includes a front arch air duct 16, a front arch air supply port 17, and a front arch air supply pipe 3, and the front arch air supply pipe 3 is located at the front arch air supply port. 17 points are connected to the front arch air delivery pipe 16, and the front arch air delivery pipe 16 is connected to the main duct 11; the front arch air supply pipe 3 is located at the upward turning point of the front arch 5 of the boiler, and the air supply direction is perpendicular to the flue gas flow direction in the lower part of the furnace ; The secondary air system is mainly to mix the volatile matter precipitated from the biomass fuel, and under the synergy with the primary air, it forms flue gas disturbance and intensifies combustion.

Referring to Fig. 1 and shown in Fig. 5, the described tertiary air system comprises a rear arch air supply duct 18, a rear arch air supply port 19, and a rear arch air supply pipe 4, and the rear arch air supply pipe 4 is located at the rear arch air supply port 19 The place is connected with the rear arch air duct 18, and the rear arch air duct 18 is connected with the main duct 11; the rear arch air supply pipe 4 is turned out on the rear arch 6 of the boiler, and the air supply direction is perpendicular to the flue gas flow direction on the upper part of the furnace. The tertiary air system is mainly to strengthen the mixing of the volatile matter precipitated from the biomass again to achieve the purpose of full combustion.

The primary air of the utility model mainly burns carbon in the fire grate, and the secondary air and the tertiary air mainly burn volatile matter. The high volatile biomass fuel is burned in stages to reduce the furnace temperature in the combustion area. Reduces the formation of thermal nitrogen oxides. The flue gas recirculation system reduces the oxygen content in the flue gas to make the oxygen content ≤ 9%, which reduces the conversion value of nitrogen oxides on the other hand. Thus reducing the emission of nitrogen oxides as a whole.

The above descriptions are only preferred examples of the utility model, and are not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made to the utility model shall be included in the protection scope of the utility model.

Claims (4)

1. A biomass boiler multi-stage air distribution system with reduced nitrogen oxides, characterized in that it includes a primary air system, a flue gas circulation system, a secondary air system and a tertiary air system, and the primary air system is located at the fire grate In the lower part, the flue gas circulation system is located on one side of the primary air system, and the secondary air system and tertiary air system are respectively located at the upturned places of the front arch (5) and the rear arch (6); The primary air system includes a fan (8), a main duct (11), a branch duct (12), a boiler air outlet (13), and nine mutually independent air chambers B (2). The fan (8) passes through The main pipe (11) and branch pipes (12) are connected to the boiler air outlet (13), and the fan (8) sends the external air to the main pipe (11) through the air pipe (10), and then sent to the main pipe (11) The branch pipes (12) of the nine air chambers B (2), the branch pipes (12) control the amount of air supplied to the pipes through the air volume automatic regulating valves (14) of each air chamber B. 2. The biomass boiler multi-stage air distribution system with nitrogen oxide reduction according to claim 1, characterized in that: the flue gas circulation system includes a circulating fan (7), a flue gas pipe (9), a flue gas Air circulation pipe (15) and an independent air chamber A (1), the flue gas pipe (9) is connected to the inlet of the circulation fan, and the outlet of the circulation fan passes through the flue gas circulation pipe (15), the automatic air volume adjustment valve (14 ) is connected with the boiler air outlet (13) in the air chamber A (1); ) side by side and evenly distributed on both sides of the grate shell; the circulation fan (7) sends the flue gas treated by the dust collector into the flue gas circulation pipe (15) through the flue gas pipe (9), and the flue gas circulation pipe (15) The flue gas is sent to the air chamber A (1), and the required air supply volume is controlled by the air volume automatic adjustment valve (14). 3. The multi-stage air distribution system for biomass boilers with reduced nitrogen oxides according to claim 1, characterized in that: the secondary air system includes a front arch air duct (16), a front arch air supply port ( 17), the front arch air supply pipe (3), the front arch air supply pipe (3) is connected with the front arch air delivery pipe (16) at the front arch air supply outlet (17), the front arch air delivery pipe (16) It is connected with the main pipeline (11); the front arch air supply pipe (3) is located at the upturned part of the front arch (5) of the boiler, and the air supply direction is perpendicular to the flue gas flow direction at the lower part of the furnace. 4. The multi-stage air distribution system for biomass boilers with reduced nitrogen oxides according to claim 1, characterized in that: the tertiary air system includes a rear arch air duct (18), a rear arch air supply port (19 ), the rear arch air supply pipe (4), the rear arch air supply pipe (4) is connected with the rear arch air delivery pipe (18) at the rear arch air supply outlet (19), and the rear arch air delivery pipe (18) is connected with the rear arch air delivery pipe (18) The main pipeline (11) is connected; the rear arch air supply pipe (4) is turned out on the rear arch (6) of the boiler, and the air supply direction is perpendicular to the flue gas flow direction on the upper part of the furnace.