Overview

SR multichannel coal and gas hybrid burner is developed and designed especially for burning coal powder and gas fuel on the rotary kiln based on four-channel burner. The burner guarantees advantages and features of four-channel burner and adds adaptability of fuel, as well as solves the problem that users cannot meet production demand by using single fuel. At present, it has been applied in chemical industry, pelletizing in metallurgical industry and lime rotary kiln at present, well appraised by users.

The burner is hybrid combustion of coal powder and gas fuel in general, which can also achieve burn coal powder or gas fuel singly.

Theory

As the following figure 1 shown, with the relatively high momentum and moment of momentum provided by adjacent swirl wind, they move forward in high speed and continue to make radial diffusion till meeting with the axial flow wind ejected in high speed. The coming of axial flow wind further enhances the mixing ofgas fule and air (including the surrounding secondary air) and the divergence degree of the flame could be adjusted. The length and thickness of flame could be adjusted according to requirement to reach the required flame shape. The function of center wind is to prompt the combustion of small amount of coal gas fuel in central part and CO, make combustion more sufficient and play flow stability function. Because of this kind of combustion mechanism and the high speed of rotational flow and axial flow wind, the combustion is very rapid and is complete.

Figure 1: Flow diagram of air flow and coal powder in multichannel coal and gas hybrid burner

Model Illustration

Characteristic

1. Flame shape is regular and complete and flame has no fluctuation and is stable. There will be no kiln liner cleaning phenomenon and the service life of kiln liner could be extended.

2. Gas fuel is well hybrid with primary air and secondary air, with full combustion, thus it can increase heat strength of the furnace, at the same time, reduce proportion of primary air, so as to increase yield of the furnace and reduce heat consumption.

3. The bowl shape effect formed by flame arrester does not have high swirl with flame at first, thus the temperature peak value is avoided and the flame temperature is made evenly and reasonably distributed, which could effectively protect the barrel and protection board of kiln eye.

4. Reduction of CO and NOX contents in exhaust gas is favorable for the safe operation of electric dust collector and environmental protection.

5. On-line regulation is convenient. The cross section of each air channel outlet could be regulated in operation so as to change the ejection speed of each air channel and reach the purpose of regulating flame shape and intensity.

6. It is applicable to long service life: the nozzle adopts special material, capable of oxidation resistance above 1200°C; there is anti-wear ceramic protection layer in coal powder inlet, which can prevent coal powder from washing the burner.

Figure 2: Flow diagram of air flow and coal powder in multichannel coal and gas hybrid burner

Construction Introduction

It is composed by pipelines, nozzle, metal corrugated compensator, butterfly valves, pressure measuring instrument and protective layer.

Pipelines: Five in total from the outside to the inside, including axial flow air channel, rotational flow air channel, coal gas channel, coal air channel, and central air channel,

Nozzle: Processed with special material. Nozzle area of each pipeline is adjustable so as to adjust the ejected wind speed. It is one of the key parts to ensure flame shape and life.

Metal corrugated compensator: It is the main part for connecting each pipeline, sealing and adjusting flame shape,

Pressure measuring instrument: Indirectly display the ejection speed of each air outlet in burner.

Protective layer: that is, refractory castable layer, the pouring shall be completed by user at site.

Inlets of axis wind flow, rotation wind flow and center wind are all installed with butterfly valves, which can adjust air volume and proportion independent. It can push in or pull out the pipe by rotating adjusting nuts, so as to jet speed through adjusting emitting area of pipes.