160 h of chemical-looping combustion in a 10 kW reactor system with a NiO-based oxygen carrier

Chemical-looping combustion, CLC, is a technology with inherent separation of the greenhouse gas CO₂. The technique uses an oxygen carrier made up of particulate metal oxide to transfer oxygen from combustion air to fuel. In this work, an oxygen carrier consisting of 60% NiO and 40% NiAl₂O₄ was used in a 10 kW CLC reactor system for 160 h of operation with fuel. The first 3 h of fuel operation excepted, the test series was accomplished with the same batch of oxygen carrier particles. The fuel used in the experiments was natural gas, and a fuel conversion to CO₂ of approximately 99% was accomplished. Combustion conditions were very stable during the test period, except for the operation at sub-stoichiometric conditions. It was shown that the methane fraction in the fuel reactor exit gas was dependent upon the rate of solids circulation, with higher circulation leading to more unconverted methane. The carbon monoxide fraction was found to follow the thermodynamical equilibrium for all investigated fuel reactor temperatures, 660–950 °C. Thermal analysis of the fuel reactor at stable conditions enabled calculation of the particle circulation which was found to be approximately 4 kg/s, MW. The loss of fines, i.e. the amount of elutriated oxygen carrier particles with diameter <45 μm, decreased during the entire test period. After 160 h of operation the fractional loss of fines was 0.00022 h⁻¹, corresponding to a particle life time of 4500 h.     

Removal of Zn and Ni by adsorption in a fixed bed of wheat straw

Zn⁺² and Ni⁺² in a solution were removed by biosorption in a fixed bed of wheat straw Triticum aestivum. The removal rate and the mass transfer coefficient for Zn⁺² and Ni⁺² were found to be proportional to the liquid superficial velocity to the power of 0.31 for the range of the particle Reynolds number from 18 to 445 (equivalent liquid rates of 0.00070–0.0175 m³ m⁻² s⁻¹). This agrees well with reported literature for mass transfer in a packed bed of solid particles under a laminar flow regime. Effect of the solution pH, temperature and the particle size (0.5, 1.0, 1.5 and 2.0 in.) on biosorption of Zn⁺² and Ni⁺² was also investigated. Biosorption of both Zn⁺² and Ni⁺² increased significantly with the solution pH from 4.0 to 7.0. On the other hand, Zn⁺² and Ni⁺² removal appeared to be insensitive to liquid temperature from 25 to 30 °C. Nevertheless, a 25% increase in the percentage removal of metal ions was observed with further increase of liquid temperature from 30 to 35 °C. However, the biosorbent particle size did not seem to have a systematic effect on the biosorption of Zn⁺² and Ni⁺². In addition, biosorption of Zn⁺² was not affected considerably by co-adsorption of the bimetal solution while biosorption of Ni⁺² decreased about 14%.     

用折流式旋转填料床处理含氨废水

采用折流式旋转填料床处理含氮废水,考察了各因素对吹脱率、传质系数及气相压降的影响、实验结果表明：在pH为10左右、温度为20℃、废水中氨质量浓度为10366mg／L、气体流星为160m^3／h、液体流晕为60L／h、转述为800r／min的条件下,吹脱率为92％,传质系数为3．46kmol／（m^3·s）;折流式旋转填料床的气相压降显著低于其他旋转填料床,且湿床压降低于干床压降;获得了折流式旋转填料床的传质系数和气相压降的回归方程,可分别计算折流式旋转填料床的传质系数和气相压降,考察传质性能和流体力学性能。     

煤燃烧固氟剂及固氟效果研究

通过热力学分析煤燃烧过程中钙基固氟剂固氟反应机理和高温高效钙基固氟剂开发原则;通过流化床和链条炉燃烧试验考察石灰石和钙基固氟剂燃烧固氟效果.试验表明:流化床燃烧时石灰石燃烧固氟效果明显,在Ca/F=60～70时,脱氟率可达到66.7%～70.0%;链条炉燃烧试验表明:利用工业废料开发的钙基固氟剂固氟效果显著,在Ca/F=65～80时,脱氟率为57.32%～75.19%.在燃煤过程添加石灰石和钙基固氟剂具有固氟固硫的双重作用.     

南方某水厂生产废水处理工艺运行中存在的问题及应对措施

通过对南方某水厂生产废水处理工艺的现场考察 ,指出了工艺中存在的主要问题 ,并作了分析讨论。利用新型造粒流化床高效污泥浓缩技术 ,对该厂的生产废水进行了现场中试实验 ,研究结果表明 ,该技术能够显著提高污泥脱水性能和排泥浓度 ,缩短了污泥水力停留时间 ,是解决南方地区自来水厂生产废水处理的一项高效实用技术     

生物流化床中生物膜特性与反应器效率的关系

综述了生物流化床处理有机废水时生物膜的特性及其对反应器效率的影响。包括反应器中生物膜的形成及影响生物膜形成的因素;生物膜的活性及膜厚、基质浓度和不同种群微生物在生物膜中的分布对其活性的影响;生物膜的传质特性;生物膜厚度与反应器效率的关系;生物膜的脱膜及其数学模型;提出了生物流化床今后的研究重点     

MD三相流化床降解含酚废水的研究

以人工配制的含酚废水作为研究对象,观察新研制的ＭＤ三相流化床好氧化物处理含酚废水的效果。试验结果表明,在进水酚浓度为４１００ｍｇ／Ｌ时,ＭＤ三相流化同水酚浓度为２０ｍｇ／Ｏ－２５ｍｇ／Ｌ,其     

边流效应对固定床吸附容量的影响

以甲苯气体为例,低浓度有机污染物在活性炭固定床吸附器内受边流效应影响的吸附过程。结果表明,由于边流效应影响,吸附床层死层增加,吸附容量减少,对直径０．３６ｍ,高径比为２．５的固定床,固定床甲苯吸附量损失可达１．７８ｋｇ,吸附层高度损失０．１２ｍ。     

生态浮床技术应用研究

随着工农业的发展,我国的水污染问题日益严重,其中湖泊、水库的富营养化问题尤为突出,如何有效控制水体富营养化是人们关注的热点问题。生态浮床技术以其独特的优点,越来越受到人们的重视,逐渐被应用于富营养化水体的治理中。分析了该技术的工作原理,介绍了国内外的一些应用实例,最后结合应用中存在的问题,对其发展前景进行了展望。     

生物流化床厌氧氨氧化脱氮处理垃圾渗滤液的研究

采用厌氧流化床反应器 (AFB)作为厌氧氨氧化反应器 ,对垃圾渗滤液脱氮进行了研究。以模拟废水完成了反应器的启动 ,然后加入一定比例的垃圾渗滤液 ,对垃圾渗滤液厌氧氨氧化脱氮的影响因素进行了研究 ,取得了较好的脱氮效果。实验表明 ,厌氧氨氧化脱氮对高氨氮浓度的垃圾渗滤液的处理具有较大的潜力。