A belt roaster low NOx combustion device

Abstract

A low NOx combustion device for a belt roaster belongs to the field of combustion technology. The combustion device includes a heat recovery air main pipe, a belt roaster upper cover, a downcomer, a combustion chamber, a combustion pre-chamber and a burner; the downcomer is located on both sides of the lower part of the heat recovery air main pipe and is connected to the combustion chamber; the burner is installed on the side of the combustion pre-chamber. The combustion-supporting air passes through the burner and performs a rich-fuel reducing combustion in the combustion pre-chamber together with the fuel, thereby suppressing the formation of NOx during the combustion process; the fuel that is not completely burned in the combustion chamber and the primary air in the heat recovery air main pipe introduced through the downcomer are further burned in the combustion chamber and the belt roaster upper cover, thereby achieving the purpose of reducing the amount of NOx generated. The advantage is that the combustion-supporting air and the primary air are supplied in stages by setting the combustion pre-chamber, thereby reducing the amount of NOx generated, and the investment is low.

Description

Technical Field

[0001] The invention belongs to the technical field of combustion, and in particular relates to a low NOx combustion device for a belt roaster. Background Art

[0002] At present, the belt roaster combustion adopts the method of primary air and combustion-supporting air entering the combustion chamber at the same time, resulting in high NOx emission concentration and high denitrification cost. Summary of the invention

[0003] The object of the present invention is to provide a low NOx combustion device for a belt roaster, which solves the problems of high NOx emission concentration and high denitration cost of the existing belt roaster.

[0004] A low NOx combustion device for a belt roasting machine comprises a heat recovery air main pipe 1, a belt roasting machine upper cover 2, a downcomer 3, a combustion chamber 4, a combustion front chamber 5 and a burner 6; the downcomer 3 is located at both sides of the lower part of the heat recovery air main pipe 1 and is connected to the combustion chamber 4, and the heat recovery air is led from the heat recovery air main pipe 1 to the combustion chamber 4; the combustion chamber 4 is connected to both sides of the belt roasting machine upper cover 2, and the other side of the combustion chamber 4 is connected to the combustion front chamber 5; the burner 6 is installed on the side of the combustion front chamber 5.

[0005] The combustion front chamber 5 has a length L of 300-2000 mm, is provided with 250-350 mm thick refractory material, and has an inner diameter of 800-2000 mm.

[0006] The method for using the combustion device, the specific steps and parameters are as follows:

[0007] 1. The combustion-supporting air passes through the burner 6 and together with the fuel, performs rich-fuel reducing combustion in the combustion antechamber 5. The flame combustion speed and temperature are reduced, thereby suppressing the formation of NOx during the combustion process.

[0008] 2. The unburned fuel in the combustion chamber 4 and the primary air in the heat recovery air main pipe 1 introduced through the downcomer 3 are further burned in the combustion chamber 4 and the upper cover 2 of the belt roaster. At this time, the fuel, hot air and the flue gas generated by the combustion in the combustion front chamber 5 are mixed and burned. The combustion temperature is low and the thermal NOx generation is reduced, thereby achieving the purpose of reducing the NOx generation.

[0009] The combustion-supporting air volume in step 1 is 10-80% of the air volume required for theoretical combustion.

[0010] The advantages of the present invention are:

[0011] 1. By setting up a combustion pre-chamber, the combustion air and primary air can be supplied in stages, thereby reducing the generation of NOx with low investment.

[0012] 2. Reduce the cost of denitrification by reducing the production of NOx.

[0013] 3. The purpose of reducing energy consumption is achieved by controlling the combustion-supporting air volume to be less than the air volume required for theoretical combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The schematic diagram of the low NOx combustion device of the belt roaster includes the heat recovery air main pipe 1, the upper cover of the belt roaster 2, the downcomer 3, the combustion chamber 4, the combustion front chamber 5, and the burner 6. DETAILED DESCRIPTION

[0015] A low NOx combustion device for a belt roasting machine comprises a heat recovery air main pipe 1, a belt roasting machine upper cover 2, a downcomer 3, a combustion chamber 4, a combustion front chamber 5 and a burner 6; the downcomer 3 is located at both sides of the lower part of the heat recovery air main pipe 1 and is connected to the combustion chamber 4, and the heat recovery air is led from the heat recovery air main pipe 1 to the combustion chamber 4; the combustion chamber 4 is connected to both sides of the belt roasting machine upper cover 2, and the other side of the combustion chamber 4 is connected to the combustion front chamber 5; the burner 6 is installed on the side of the combustion front chamber 5.

[0016] The length L of the combustion front chamber 5 is 800 mm, and a 300 mm thick refractory material is arranged inside, and the inner diameter of the cavity is 1300 mm.

[0017] The method for using the combustion device, the specific steps and parameters are as follows:

[0018] 1. The combustion-supporting air passes through the burner 6 and together with the fuel, performs rich-fuel reducing combustion in the combustion antechamber 5. The flame combustion speed and temperature are reduced, thereby suppressing the formation of NOx during the combustion process.

[0019] 2. The unburned fuel in the combustion chamber 4 and the primary air in the heat recovery air main pipe 1 introduced through the downcomer 3 are further burned in the combustion chamber 4 and the upper cover 2 of the belt roaster. At this time, the fuel, hot air and the flue gas generated by the combustion in the combustion front chamber 5 are mixed and burned. The combustion temperature is low and the thermal NOx generation is reduced, thereby achieving the purpose of reducing the NOx generation.

[0020] The combustion-supporting air volume in step 1 is 13% of the air volume required for theoretical combustion.

Claims

1. A belt roaster low NOx combustion device, characterized in that: The invention comprises a heat recovery air main pipe (1), an upper cover (2) of a belt roasting machine, a downcomer (3), a combustion chamber (4), a combustion front chamber (5) and a burner (6); the downcomer (3) is located at both sides of the lower part of the heat recovery air main pipe (1) and is connected to the combustion chamber (4), and guides the heat recovery air from the heat recovery air main pipe (1) to the combustion chamber (4); the combustion chamber (4) is connected to both sides of the upper cover (2) of the belt roasting machine, and the other side of the combustion chamber (4) is connected to the combustion front chamber (5); the burner (6) is installed on the side of the combustion front chamber (5); The combustion front chamber (5) has a length L of 300-2000 mm, is provided with 250-350 mm thick refractory material, and has an inner diameter of 800-2000 mm; The operating steps and parameters of the combustion device are as follows: 1) The combustion-supporting air passes through the burner (6) and together with the fuel, performs fuel-rich reducing combustion in the combustion front chamber (5), the flame combustion speed and temperature are reduced, and the formation of NOx is suppressed during the combustion process; 2) The fuel that is not completely burned in the combustion chamber (4) and the primary air in the reheated air main pipe (1) introduced through the downcomer (3) are further burned in the combustion chamber (4) and the upper cover (2) of the belt roaster. At this time, the fuel, hot air and the flue gas generated by the combustion of the combustion front chamber (5) are mixed and burned, the combustion temperature is low, and the amount of thermal NOx generated is reduced; The amount of combustion-supporting air in step 1) is 10-80% of the amount of air required for theoretical combustion.

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