Emission characteristics of swirl premixed combustion stabilized using a displacing bluff body

doi:10.16085/j.issn.1000-6613.2021-2366

Abstract

Abstract:

The emission control of the combustion process in petrochemical and heating furnaces is of a great significance. Swirl combustion has the potential of low NO _x emission, attracting wide attention from both academia and industry. Combining the advantages of bluff body combustion and swirl combustion, a swirl premixed burner integrated with a displacing bluff body is proposed in this study. The structure of the displacing bluff body was first optimized based on the investigation into the emission under different bluff body structures. Subsequently, the studies on emission, flame morphology, and temperature distribution were conducted. The results showed that the smaller inverted cone-shaped bluff body with the half-cone angle of 30° provided relatively lower NO _x and CO emissions. The NO _x emission first decreased and then increased as the swirl number increased from 0 to 0.83, with the NO _x emission being the lowest when the swirl number was 0.25. At the same thermal power of the combustion, the flame height decreased as the swirl number increased. At the same swirl number, the flame width increased as the thermal power increased. The trend of NO _x emission variation was consistent with that of temperature. The lower NO _x emission was, the lower temperature of the corresponding flame would be. Thereby, it is expected that the temperature change caused by the swirl number variation is one of the main reason for the NO _x emission variation. The conclusion of present study provides a theoretical basis for the design of swirl premixed burner.

Key words: lean premixed combustion, bluff body, swirl combustion, nitrogen oxides, temperature field

摘要：

石化炉、加热炉等设备中燃烧过程的污染物控制具有重要意义。旋流预混燃烧过程具有低NO _x 排放的潜力，引发了学术界和工业界的广泛关注。结合钝体燃烧和旋流燃烧各自的优势，本文设计了带有位移钝体的旋流预混燃烧器。首先研究了不同钝体结构下的污染物的生成情况，确定了最优的钝体结构，在此基础上进一步研究了在不同旋流数下污染物生成、火焰形态和温度场分布情况。研究发现，钝体角度为30°、体积较小的倒锥形钝体具有较低的NO _x 和CO生成量。NO _x 生成量随着旋流数从0增加到0.83呈先减小后增加的趋势，并且当旋流数为0.25时，NO _x 生成量最低。在同一热功率下，火焰高度随着旋流数的增加而减小。在同一旋流数下，火焰宽度随热功率增大呈增大趋势。NO _x 生成量变化规律与其火焰温度分布规律一致，即NO _x 生成量最低的工况下火焰温度也比较低。由此推测旋流引发的温度变化是NO _x 生成量变化的主要影响因素之一。本文的研究结论对旋流预混燃烧器的设计提供了理论基础。

关键词: 贫燃预混燃烧, 钝体, 旋流燃烧, 氮氧化物, 温度场

CLC Number:

TK16

HAN Delin, LI Dan, WANG Tiantian, ZHANG Hai, ZHANG Yang, WANG Suilin. Emission characteristics of swirl premixed combustion stabilized using a displacing bluff body[J]. Chemical Industry and Engineering Progress, 2022, 41(6): 2915-2923.

韩徳琳, 李丹, 王天天, 张海, 张扬, 王随林. 位移钝体稳燃的旋流预混燃烧污染物生成特性[J]. 化工进展, 2022, 41(6): 2915-2923.

Figures/Tables 11

角度α	旋流数S
0°	0
10°	0.12
20°	0.25
30°	0.4
40°	0.59
50°	0.83

物理量	仪器名称	量程	误差
$Q C H 4$	音速喷嘴+压力表	0~2MPa	±0.25%量程
Q_air	质量流量计	0~200L/min	±1%量程
T	B型热电偶	800~1700^oC	±0.5%
O₂质量分数		0~21％	0.1％
NO浓度	ECOM-J2KN	0~4000μL/L	±2%测量值
NO₂浓度	烟气分析仪	0~500μL/L	±2%测量值
CO浓度		0~4000μL/L	±2%测量值

物理量	仪器名称	量程	误差
$Q C H 4$	音速喷嘴+压力表	0~2MPa	±0.25%量程
Q_air	质量流量计	0~200L/min	±1%量程
T	B型热电偶	800~1700^oC	±0.5%
O₂质量分数		0~21％	0.1％
NO浓度	ECOM-J2KN	0~4000μL/L	±2%测量值
NO₂浓度	烟气分析仪	0~500μL/L	±2%测量值
CO浓度		0~4000μL/L	±2%测量值

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