餐饮业烟道油垢燃烧特性及动力学模型

利用热重分析仪研究了餐饮业油烟道油垢在不同升温速率下的燃烧特性.所采用的升温速率分别为5℃/min、15℃/min和25℃/min.吹扫气体为干空气,流量为20 mL/min.结果表明,试样从常温至800℃的升温燃烧经历了第1步水分析出、第2～5步燃烧失重过程.采用Doyle和Coats-Redfern方法建立了"4阶段1级反应动力学模型",计算燃烧反应的动力学参数.并用试验热重曲线验证了模型的可靠性.研究表明,油垢燃烧失重的4个主要过程均可用简单反应动力学模型进行简化,反应级数为1;燃烧总趋势是随升温速率提高,活化能增大.

Combustion characteristics of cooking oil tar in the smog-discharging pipes and its kinetics model

This paper intends to introduce the author's field experimental analysis on the combustion characteristics of cooking oil tar in the smog-discharging pipes. As is known, it is very important to prevent fire flame in the smog-discharging pipe in a cooking system, which is likely to bring about not only huge economic loss, but also human casualty and some other adverse social impacts. The chief combustible material in a smog discharge pipe is, as a matter of fact, the cooking oil tar. In order to solve the problem of fire-appearance in smog discharging pipe, it is necessary to study the combustion characteristics of cooking oil tar and devise a feasible automatic fire-alarming system as well as a fire-extinguishing system. It is just for solving the above problem that we have devised a test for measuring the combustion features of cooking oil tar in the pipe by using a thermo-gravimetric and thermo-graphical analyzer known as TG209C with three heating rates of 5℃/min, 15℃/min and 25℃/min respectively. In the test, the sweeping gas was the dry air with a turning rate of 20 mL/min. The experimental results show that the weight loss of the oil tar can be divided into five stages, that is, the process of water separation and the following four stages, that is, the combustion process at various speeds, which can be expressed by the first order reaction kinetic model of Doyle and Coats-Redfem methods. Then, the model was tested and proved to be feasible for the purpose as well as dependable on the experimental TG cures. Moreover, the combustion reaction can be described by the four first-order equations. The experiments also show the activating energy increases proportionally with the rise of the heating temperature.