热辐射通量对谷物粉尘燃烧特性的影响
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摘要
为研究热辐射通量对谷物粉尘燃烧特性的影响,以可食用玉米淀粉为研究对象,采用锥形量热仪(CONE)研究不同热辐射通量对热释放速率、质量损失速率、烟气温度、引燃时间等的影响。原料分别过120、140、160、180、200目标准筛进行筛分,于22、24、26、28、30 kW/m~2热辐射通量下进行点火燃烧实验。结果表明:相同测试条件下,玉米淀粉热释放速率峰值随热辐射通量的增大而增加,30 kW/m~2时峰值强度增大至最大80.293 6kW/m~2。热辐射通量变化对平均热释放速率、平均有效燃烧热、放热总量的影响较小。质量损失速率变化曲线随热辐射通量的增加向左移动,辐射通量22 kW/m~2质量损失速率曲线呈现一个较大的峰,其他辐射通量时均呈现双峰特征。烟气温度变化曲线随热辐射通量的增加整体向上移动。引燃时间随热辐射通量的增加而减小,呈线性减小关系且影响较大:热辐射通量为22 kW/m~2时,引燃时间为104 s;30 kW/m~2时,引燃时间减小至58 s。故相关涉粉企业在生产过程中应加强厂房内通风换气,严格控制设备、通风除尘管道等的温度避免内部热辐射温度过高。
In order to study the effect of thermal radiation flux on combustion characteristics of grain dust, taking edible corn starch as the research object, CONE calorimeter was used to systematically study the effects of different thermal radiation flux on heat release rate, mass loss rate, flue gas temperature and ignition time.Raw materials were screened through 120, 140, 160, 180 and 200 target quasi-sieves, and ignition combustion experiments were car-ried out under the condition of 22, 24, 26, 28 and 30 kW/m~2 heat radiation flux.The results showed that: Under the same test conditions, the peak value of the thermal release rate of corn starch increased with the increase of thermal radiation flux, and the peak strength increased to 80.293 6 kW/m~2 at 30 kW/m~2; The change of heat radiation flux had little effect on the average heat release rate,the average effective heat of combustion and the total amount of heat release; The change curve of mass loss rate moved to the left with the increase of thermal radiation flux, and the mass loss rate curve of 22 kW/m~2 of radiant flux presented a larger peak, while that of the other radiation fluxes showed bimodal characteristics;The flue gas temperature curve moved upward as the heat flux increased; The ignition time decreased with the increase of thermal radiation flux, showing a linear decreasing relation and a great in-fluence: when the thermal radiation flux was 22 kW/m~2, the ignition time was 104 s; At 30 kW/m~2, the ignition time decreased to58 s. Therefore, the related powder enterprises should strengthen ventilation in the workshop during production, and strictly control the temperature of equipment and ventilation dust removal pipeline to avoid excessive internal thermal radiation temperature.
In order to study the effect of thermal radiation flux on combustion characteristics of grain dust, taking edible corn starch as the research object, CONE calorimeter was used to systematically study the effects of different thermal radiation flux on heat release rate, mass loss rate, flue gas temperature and ignition time.Raw materials were screened through 120, 140, 160, 180 and 200 target quasi-sieves, and ignition combustion experiments were car-ried out under the condition of 22, 24, 26, 28 and 30 kW/m~2 heat radiation flux.The results showed that: Under the same test conditions, the peak value of the thermal release rate of corn starch increased with the increase of thermal radiation flux, and the peak strength increased to 80.293 6 kW/m~2 at 30 kW/m~2; The change of heat radiation flux had little effect on the average heat release rate,the average effective heat of combustion and the total amount of heat release; The change curve of mass loss rate moved to the left with the increase of thermal radiation flux, and the mass loss rate curve of 22 kW/m~2 of radiant flux presented a larger peak, while that of the other radiation fluxes showed bimodal characteristics;The flue gas temperature curve moved upward as the heat flux increased; The ignition time decreased with the increase of thermal radiation flux, showing a linear decreasing relation and a great in-fluence: when the thermal radiation flux was 22 kW/m~2, the ignition time was 104 s; At 30 kW/m~2, the ignition time decreased to58 s. Therefore, the related powder enterprises should strengthen ventilation in the workshop during production, and strictly control the temperature of equipment and ventilation dust removal pipeline to avoid excessive internal thermal radiation temperature.
引文
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[2]ALVARO R,JAVIER G T,PEDRO J.Aguado.Determination of parameters used to prevent ignition of stored materials and to protect against explosions in food industries[J].Journal of Hazardous materials,2009,(1):163-167.
[3]陈春燕,龙思华,肖国清,等.基于响应面方法的甘薯粉尘爆炸研究[J].中国安全科学学报,2017,27(1):42-47.
[4]曹卫国,郑俊杰,彭于怀,等.玉米淀粉粉尘爆炸特性及火焰传播过程的试验研究[J].爆破器材,2016,45(1):1-6.
[5]张洪铭.玉米淀粉粉尘火焰传播及热分析动力学特性实验研究[D].武汉:武汉理工大学,2015.
[6]王正洲,袁宏永,范维澄,苏国锋.烟叶的燃烧和着火特性的研究[J].火灾科学,2000,(1):44-48.
[7]余明高,孟牒,路长,等.不同热辐射强度下秸秆燃烧特性实验研究[J].火灾科学,2010,19(4):212-216.
[8]斯·阿丹特,法兰克·赫尔特,李刚,等.港口散粮设备粉尘爆炸危险性分析及其防护[J].中国粉体技术,1999,(2):31-34.