循环流动固定床光催化反应器动力学数学模拟

以甲基橙为模型反应物,研究了连续循环固定床光催化反应器的动力学过程.根据光催化氧化过程特点,分析并建立了准一级反应动力学方程,对该反应系统的动力学过程进行动态数学模拟,用四阶Runge-Kutta法进行数值计算,结果表明数学模拟与实验数据相吻合.在该光催化反应体系中,处理量增加时实际反应速率常数k基本不变,而表观反应速率常数kapp变小,二者之间关系与反应器体积对处理量体积比（γ）密切相关;反应速率常数受起始浓度影响很大,在15～150 μmol•L－1浓度范围内,lnk=－0.48ln[c0]＋1.42;反应速率常数与光强的关系为k∝I0.5;反应速率常数受溶液pH值的影响也很大.     

城市垃圾与煤在CFBC试验台上的混烧试验

城市垃圾的焚烧处理一直是人们关注的研究领域。本文详细报告了一种城市垃圾与劣质煤在0.15兆瓦CFBC试验台上的混烧试验。试验结果表明,城市垃圾与劣质煤在循环流化床中的混烧可以很好地满足稳定和高温燃烧的要求,通过添加石灰石等含钙物料可以有效地在燃烧过程巾控制SO2、HCl和二(?)英类污染物的生成。     

生物质洁净能源研究中的流化床动力学模型

分别对最小流化床、鼓泡流化床和腾涌流化床及相应的全混模型、鼓泡模型、气泡汇集模型等加以综述 ,分析其优缺点 ,并在此基础上提出动力学模拟研究的新思路 .根据流化床内在的本质———流化态的不同 ,将流化床分为最小流化床、鼓泡流化床和腾涌流化床三种 .总结了前人针对各种流化床提出的全混模型、鼓泡模型、气泡汇集模型等思想 ,建议今后可以在以下几个方面进行深入研究 :⑴使得模型更有普适性 .⑵由于气泡有效直径尚不能在理论上求得 ,可以在理想气泡直径变化公式的基础上 ,加入非线性化学的计算 .⑶确定不同情况下的参数 ,使得工作更有延续性 ,也使得模型更加具有生命力 .⑷从高压的角度去进行模型的计算 ,并得到相应的试验数据支持 .     

旋涡流化床颗粒夹带和扬析的数学模型

本文结合气体湍流运动模型，颗粒运动的轨道模型和密相床层动力学的经验关联式，建立了旋涡流化床颗粒夹带和扬析的数学模型，发展了相应的求解程序。用本文提出的数学模型对普通鼓泡流化床中颗粒夹带的计算结果与前人的经验公式相符；对旋涡流化床和普通的鼓泡流化床颗粒扬析的计算结果与实验数据吻合较好。     

基于红外光谱研究沥青燃烧机理和有害气体成分分析

利用Rosemount气体分析仪和定碳炉搭建起固定床燃烧反应试验平台,通过红外光谱分析技术定量分析沥青及其胶浆在高升温速率条件下燃烧反应的有毒气态产物成分、及其释放规律。研究表明,在高升温速率、近等温条件下,沥青及胶浆的燃烧过程可近似分为活泼挥发组分析出燃烧、二次挥发析出结合残炭燃烧两个阶段,其主要气态产物为CO₂,CO,NO,NO₂及SO₂。沥青材料中活泼挥发组分含量是影响燃烧气态产物释放规律的关键因素之一,减少沥青材料中活泼挥发组分的含量可有效降低燃烧气态产物的生成、尤其是CO的产生。     

作物生长的土壤中氧气浓度场的稳态数值模拟

建立了一个描述土壤中热、湿、气耦合迁移的数学模型,对有冬小麦生长的圆柱形土壤床中的氧气浓度场进行 了数值模拟。结果表明,土壤床中的氧气浓度场与冬小麦的生长发育阶段、上壤的孔隙率以及土壤床的高度等因素密切相 关。     

New sorption and solvation measuring methods: Forced flow through liquids and solid state fluidised bed sorbents in high pressure gravimetry

A novel measuring method is presented here that allows sorption and solvation measurements near to different process conditions. Especially for the sorption kinetics it is important that the measuring conditions are similar to later applications. Particularly for high pressure sorption measurements this claim could not be fulfilled for most technical applications.The advantage of the measuring methods presented here is that solid bed samples in high pressure gravimetry can be measured under flow-through conditions in both directions and, for the first time in high pressure gravimetry, liquid samples can be measured under flow-through conditions. Especially for ionic liquids, of which a large variety of new substances with unknown sorption potentials have been synthesised in the last few years, this results in much shorter measuring times.The first measurements presented here show that the new system allows for measuring times around 26 times shorter for an ionic liquid.     

Fluidization of Nano-size Particles

Fluidization and collapsing bed experiments were performed with 'Tullanox', 10nm diameter fumed silica. The minimum fluidization velocity was determined to be 0.0115m/s at the unusually low volume fraction of solids of 0.0077. The solids volume fraction was measured using a -ray densitometer. Fluidization was without large bubbles, with a high bed expansion ratio. The highest granular temperature was of the order of that of Geldart B particles, as measured by Cody et al. (1996). The sedimentation process was simulated using a two-fluid hydrodynamic model. The input into the model was a measured solids stress modulus and an agglomerate size determined from the settling curves. With these two rheological parameters, there was good agreement between the sedimentation theory and the experiment. This study shows that the standard collapse bed experiment used in industry is a good test of rheological properties of particles.     

Removal of dust from flue gas in magnetically stabilized fluidized bed

A magnetically stabilized fluidized bed (MSFB, φ 500mm x 2100mm) was designed to study dust removal from flue gas. Based on the mechanism of dust removal in a fixed bed, the effects on collection efficiency of magnetic field intensity, ratio of flue gas velocity to minimum fluidization velocity, bed height, and particle average diameter, were investigated. Then feasible methods for MSFB to better remove dust were proposed. Over 95% of dust removal with MSFB can be achieved, when stable fluidization is maintained and when magnetic particles are frequently renewed.