净水用颗粒活性炭对水中余氯去除的动力学原理效能

比较不同类型活性炭对水中余氯的去除效能,为家用净水器筛选最佳除氯用活性炭,以7种活性炭(木质活性炭、果壳活性炭、椰壳活性炭、煤质活性炭、压块破碎煤质炭、酸洗煤活性炭、煤质活性炭纤维)为研究对象,系统性开展了活性炭去除水中自由氯和一氯胺的效能和动力学规律研究。试验结果表明:活性炭去除自由氯的和一氯胺的速率符合拟一级反应动力学模型,相关性系数在0.96以上。材质为煤的活性炭去除自由氯和一氯胺速率相对较快,去除速率为煤质活性炭纤维酸洗煤煤质活性炭压块破碎炭椰壳活性炭木质活性炭果壳活性炭,在温度为25℃、酸碱度为7.5的条件下,活性炭纤维去除自由氯速率达11.91 h~(-1)。比表面积是影响活性炭除氯的主要因素之一,相关性系数达到0.999 9。温度的升高和pH的降低都能提高活性炭的除氯效率。     

基于热分析法的神府粉煤低温热解影响因素研究

利用TG-DTG热分析仪对神府粉煤热解特性进行实验研究,考察升温速率、煤样粒径和载气流速对神府粉煤热解过程的影响,并通过正交实验确定最大失重速率的最佳条件.热重实验结果表明:升温速率、煤样粒径和载气流速对热解失重均有影响.升温速率和载气流速增大,热解失重量减少.粒径对热解失重率的影响呈抛物线分布,最大热解失重量存在最佳粒径,本实验所研究的粒径小于0.84mm的神府煤,热解过程中最佳粒径为0.25mm~0.42mm.正交实验结果表明:升温速率是影响煤热解过程的主要因素,其次是粒径,载气流速对热解影响最小;当神府煤的煤样粒径为0.25mm~0.42mm、升温速率为30℃/min、载气流速为120mL/min时,热解失重速率最大,为4.95%/min.     

无定型碳的微波损耗特征及其耦合热转换影响因素分析

运用多物理场耦合软件COMSOL的微波加热模块对微波加热无定型碳的动态过程进行了模拟分析。结果表明微波加热是整体性加热,由外而内碳的升温速率逐渐降低,随着热传递的进行,内外温度趋于一致。忽略磁损耗效应,电损耗功率密度与升温速率正相关。电导损耗功率密度与电场模下降趋势相同,2 s之后介电损耗占主导。介电常数实部单独增大时,电损耗减小,升温速率降低;介电常数虚部单独增大时,介电损耗先增大后减小,升温速率先升高后降低;电导率单独增大时,电导损耗增大,升温速率提高。微波输入功率减小时,电损耗减小,升温速率降低。碳与空气存在热交换时,升温速率和温度梯度都有小幅降低,升温趋势基本不变。点掺杂Al_2O_3时,掺杂点周围温度变化平缓,中心点升温速率提高,温度梯度大幅减小,升温趋势基本不变。微波加热时间为7 s时,介电损耗最大,升温速率最高,7 s之后升温速率开始降低。     

r微波辐照再生载氮氧化物活性炭的实验研究

采用微波辐照法,对制药厂载氮氧化物活性炭再生进行了研究。考察了微波功率、载气线速度、再生时间、活性炭质量、再生次数对活性炭再生率的影响。结果表明：在微波功率为600W,载气线速度为0．002m／s,活性炭质量为15g,辐照时间100s时,活性炭再生率达到94％;活性炭再生率随着再生次数的增加而降低。     

活性炭辅助微波协同活化煤矸石过程

选择颗粒活性炭作为微波场中煤矸石活化的传热介质,将70日活性炭与10.00 g 200日煤矸粉以2.0∶1的质量配比充分混合后在800W微波功率下活化20 min,铝铁浸出率可达750℃焙烧2h方法的1.714倍.在680W功率下,活性炭的微波附着速率常数kα为0.334 min-1,微波脱附速率常数k'α为0.050 min-1,煤研粉的微波附着速率常数kb为0.262 min-1.在528,680和800 W三个功率水平下,升温动力学模型的计算值与实验值吻合很好,且各动力学参数与颗粒活性炭及煤矸粉的粒径均无关.在以上三种功率下,活性炭经两次循环后活性炭极限温升△TAmax比新炭分别提高33,16和7K,表明该过程为协同活化.得铝铁相对浸出率α与煤矸粉温升△TB成正比,比例系数为1.246×10-3K-1,得到了以α为目标的动力学方程.     

活性炭对丁酮的吸附动力学研究

研究了2种活性炭（木质活性炭和煤质活性炭）对丁酮的吸附,重点考察了活性炭的吸附时间、吸附温度和丁酮载气流量对丁酮吸附的影响,并用准一级、准二级、Elovich和Bangham 4种动力学模型对活性炭在不同温度条件下对丁酮的吸附行为进行了动力学拟合,确定其动力学吸附模型。实验表明：不同的活性炭对丁酮的吸附过程不同;活性炭对丁酮的吸附是一个吸附和解吸同时存在的过程,当吸附速率和解吸速率相等时,该过程达到吸附平衡;随着吸附温度的升高,活性炭对丁酮的饱和吸附量逐渐降低,说明活性炭对丁酮的吸附过程为放热反应;丁酮载气流量对活性炭吸附丁酮达到饱和的时间以及吸附速率有影响,对AC-1的最终饱和吸附量影响显著,对AC-2的最终饱和吸附量没有显著影响。这2种活性炭吸附丁酮最适宜的吸附温度均为303 K,最佳的载气流量为400 mL/min。在不同温度下对活性炭吸附丁酮的过程进行动力学分析,发现Bangham方程计算得到的相关系数R²大于0.99,因此,活性炭对丁酮的吸附动力学方程符合Bangham动力学方程。     

生物质微波热解影响因素的研究

针对大尺寸生物质热解的特点,采用预热工艺和热解工艺相结合的方法,对木渣进行了微波热解。在此基础上,系统研究了热解温度、微波功率、升温速率、预热时间、预热温度等工艺参数对热解产物分布及其组成的影响。实验结果表明,在预热温度160℃,预热时间15 min,裂解功率400 W,裂解温度600℃,升温功率1 000 W的条件下,得到生物油最大产率47.2%,生物炭产率为24.35%,合成气产率为28.45%。生物油成分主要为芳香族化合物和呋喃类化合物。     

微波法制备污泥活性炭及其脱色性能的研究

本研究以污水厂剩余污泥为原料采用微波-物理法制备活性炭,研究了微波加热工艺对活性炭吸附性能的影响。结果表明：对活性炭碘吸附值影响最大的是微波功率,其次是辐照时间,最后是污泥的粒径,最佳的微波处理条件为：微波功率为500W,辐照时间为2min,污泥的粒长为0．9mm;所制得的污泥活性炭用于处理染料废水,其最佳脱色率优于商品活性炭。     

微波诱导活性炭纤维催化还原NO

采用微波辐照活性炭纤维(ACFs)催化还原一氧化氮(NO)进行脱氮,研究了气体流量、微波辐照功率对脱氮效率的影响,探讨了微波诱导催化反应的机理。结果表明:ACFs在微波场中升温迅速并最终保持最高温度;微波辐照功率对NO脱除率影响较大;在ACFs质量0.25g,辐照功率100W,NO流量50mL/ min条件下,99.87%的NO可被还原为氮气。     

煤质与木质活性炭吸附处理焦化RO浓水及再生试验研究

以某钢铁厂焦化RO浓水为研究对象,采用煤质颗粒活性炭与木质颗粒活性炭进行吸附处理,考察了活性炭投加量、 pH值、吸附时间对吸附效果的影响,同时进行2种活性炭的Freundlich吸附等温线研究,研究了再生温度、再生时间、再生次数对活性炭再生后吸附性能及再生损失的影响。结果表明,在最佳吸附条件下,煤质和木质活性炭对废水中COD的去除率分别为61.1%、 56.3%。最佳再生温度为500℃,煤质和木质活性炭最佳再生时间分别为1.5 h和1.0 h。多次再生试验证明,煤质活性炭可进行大于6次的再生,使用寿命优于木质活性炭。     

Analysis of the Rapid Carbothermal Reduction Synthesis of Ultra-Fine Silicon Carbide Powders

A nondimensionalized and scaled nonisothermal model is developed for the "rapid carbothermal reduction" synthesis of sub-micron silicon carbide particles in an aerosol flow reactor to determine the minimum parametric representation of the system. Seven dimensionless groups are needed to completely describe the system, and these dimensionless groups are varied to determine the effects of the furnace wall temperature, inlet carbon particle size, carrier gas flow rate, and solids feed rate on final product quality. Analysis shows that radiation dominates the heating process, sintering dominates the primary particle growth, and conversion is controlled with precursor carbon particle size, wall temperature, and carrier gas flow rate.     

Study on preparation and desulfurization characteristics of biomass activated carbon by microwave heating CO2 activation method

Taking soybean straw rich in nitrogen-containing functional groups as the raw material precursor, combined with the special advantages of microwave heating, microwave heating technology is applied to the pyrolysis and activation process of soybean straw. The pyrolysis solid product is used as the activation raw material, and CO₂ is used as the activator to study the preparation of activated carbon, in order to prepare the biomass activated carbon with high desulfurization performance. First, the optimal activation level was obtained by orthogonal experimental design and range analysis. Then, the effects of microwave power, CO₂ flow rate and activation time on the yield, pore structure and desulfurization performance of activated carbon were investigated by single factor experiment. The optimal activation conditions were selected by comparative analysis: microwave power 900 W, CO₂ flow rate 0.10 L/min, activation time 20 min. Under these conditions, the yield of activated carbon is 76.3%(mass), the SO₂ adsorbance quantity is 112.56 mg/g, specific surface area is 466.28 m²/g. Compared with pyrolytic carbon, activated carbon has larger specific surface area and more abundant pores and significantly improved desulfurization performance.     

微波辐射-KOH活化兰炭粉制备活性炭

研究了以兰炭粉为原料,KOH为活化剂,采用微波辐射法制备活性炭的可行性。探讨了微波功率、碱炭质量比和活化时间对活性炭吸附性能的影响。同时采用美国ASAP-2020吸附仪测定了所制备活性炭的N2吸附脱附等温线和孔径分布,采用红外光谱分析了样品的表面官能团。结果表明:微波功率为700 W,碱炭质量比为3,活化时间为15 min工艺条件下制得的活性炭碘吸附值为694.5 mg/g,比表面积为513.62 m2/g,总孔容为0.510 3 cm3/g,平均孔径为3.973 8 nm,该活性炭为中孔型。以兰炭粉为原料,传统加热和微波加热制备的活性炭红外光谱图其峰形基本一致,只是峰强不同。     

微波加热CO2活化法制备生物质活性炭及其脱硫性能研究

以富含含氮官能团的大豆秸秆为原料前体,结合微波加热的特殊优势,将微波加热技术应用于大豆秸秆热解和活化工艺。以热解固体产物为活化原料,以CO₂为活化剂进行活性炭制备研究,以期制备出高脱硫性能的生物质活性炭。首先通过正交实验设计及极差分析得出最优活化水平,再通过单因素实验法考察微波功率、CO₂流量和活化时间对活性炭产率、孔隙结构以及脱硫性能的影响。对比分析选出最佳活化条件为微波功率900 W,CO₂流量0.10 L/min,活化时间20 min。在此条件下活性炭产率为76.3%（质量）,SO₂饱和吸附容量为112.56 mg/g,比表面积为466.28 m²/g。相比热解炭,活性炭的比表面积更大,孔隙更加丰富,脱硫性能显著提高。     

石油焦制备活性炭工艺条件的优化及其孔结构表征

以独山子石油焦为原料,以氯化锌为活化剂,采用微波加热方式制备活性炭,通过碘吸附、苯吸附等考察所制活性炭的吸附性能,并对活性炭的制备工艺条件进行筛选和优化。结果表明：微波加热法制备活性炭时,最佳工艺条件是：氯化锌、石油焦、煤沥青的质量比为1．5：7．5：1,微波功率1300W,辐照时间6min。所得样品比表面积1095．7m^2／g,碘吸附值673．7mg／g,苯吸附值781．1mg／g,强度20．3N。通过与电炉法对比发现,微波加热和电加热制备的活性炭孔结构不同,微波法制备的活性炭在比表面积、孔径分布等方面优于电炉法制备的活性炭。     

Effects of carbonization conditions on the properties of coal-based microfiltration carbon membranes

Carbon membranes, a novel porous inorganic membrane, have considerable potential applications in many industrial fields owing to their better stability in aggressive and adverse environments. However, the high cost of precursor materials has hampered their wide applications on commercial scale. In this study, coal, a cheap material, is used to prepare the tubular microfiltration carbon membranes. The effects of carbonization conditions on the properties of coal-based carbon membrane were investigated by the variation of the weight loss, shrinkage ratio of tube size and pore structure characteristics during carbonization. The results show that carbonization conditions greatly affect the properties of coal-based carbon membranes. The carbon membranes carbonized in the inert gases have more “open” porous structure and high gas flux compared to those carbonized in vacuum which makes the carbon membrane possess smaller pores and low gas flux. The carbonization temperature plays an important role in the determination of the pore structure and densification of carbon matrix. At the temperature below 600°C, the pore structure and carbon matrix of carbon membrane are formed with more than 95% of the total weight loss and only 48% of the total size shrinkage ratio. The matrix of carbon membrane gets more compact with the temperature increasing from 600°C to 900°C, in which the size shrinkage ratio is up to 52% with only 5% of the total weight loss. The low heating rate should favor the preparation of the carbon membranes with small average pore size and narrow pore size distribution, and the high gas flow rate can produce the carbon membranes with large average pore size and high porosity.