摘要
为了解在不同氧气浓度下污泥的热解燃烧行为和动力学机理,利用热重差热分析仪,在不同氧气浓度下,对经过不同干燥温度干燥的污泥样品进行热重差热实验。通过分析氧气浓度和干燥温度对样品热分析曲线的影响发现,干燥温度对污泥样品热分析的影响很小,但氧气浓度对其有明显的影响;随着氧气浓度的增加,热分析曲线有规律的向左偏移。在此基础上,提出污泥在不同氧气浓度条件下3种物质独立反应的热化学反应动力学模型。在该模型中,3个阶段分别对应3种不同的物质独立反应。在各种氧气浓度条件下,这3种物质的反应过程均符合一级反应模型。随着氧气浓度的上升,3个阶段对应的活化能和频率因子呈现上升趋势。
The given paper aims to report the authors＇ study over the dynamic characteristics of thermal analysis of sludge treatraent under different oxygen concentration. For our purpose, experiments with the sludge after desiccation at the temperature of 105 ℃ and 90 ℃ were done in different oxygen concentration. Analyzing the TG, DTG and DTA curves under different oxygen concentration and desiccation temperature, it was found that the effect of desiccation temperature on the pyrolysis of sludge is negligible while the effect of oxygen concentration on it accounts. The thermal pyrolysis of the sludge samples（ dry basis） consists of three clear-cut mass loss stages in all the situations, while oxygen concentration has its regular effect on the above said stages. That is to say, at the stage from 25 ℃to 150 ℃, oxygen concentration has little effect on the loss of water and small volatile; and from 200 ℃ to 380 ℃, TG , DTG and DTA curves drift regularly to the left as the oxygen concentration increases and the pyrolysis and combustion go faster; however, from 200 ℃ to 380 ℃ , the TG, DTG and DTA curves continue to drift regularly to the left. Thus, in terms of kinetic model, it can be assumed that the three components would decompose respectively at the three different mass loss stages： the pseudo component 1 decomposes at the first stage, the pseudo component 2 at the second while the pseudo component 3 at the third. There are ten reaction models herein which can be used to simulate the two components of thermal decomposition. Thus, the resuhs of our experiments show that the first order model gives the best tits to experiment data of samples in all the conditions above stated. And the kinetic parameters activation energy of the three components may increase with the increase of oxygen concentration, which contradicts the physical meaning of the activated energy.
出处
《安全与环境学报》
CAS
CSCD
2006年第6期5-8,共4页
Journal of Safety and Environment
关键词
环境工程
污泥
热解
燃烧
动力学
氧气浓度
safety engineering
sludge
pyrolysis
combustion
kinetics
oxygen concentration
