转晶剂对磷石膏制备无水硫酸钙影响的研究

磷石膏(PG)产生量大、资源化利用困难,严重影响磷化工行业的发展。为提高PG应用附加值,以除杂后的PG为原料,以NaCl和乙二胺四乙酸二钠(EDTA-2Na)为转晶剂,采用常压盐溶液法制备高白度无水CaSO₄。通过SEM、XRD、FT-IR、粒度分析仪等分析方法研究转晶剂对无水CaSO₄制备的影响。结果表明：当NaCl质量分数为15%、EDTA-2Na质量分数为0.5%时,PG结晶水脱水时间由120 min缩短至40 min,脱水效果显著;同时,无水CaSO₄晶体粒度分布均匀,颗粒表面完整,D₅₀为5.26μm,白度值为92.5%,P₂O₅质量分数仅为0.045%。这主要是因为非晶格Na⁺降低了体系中水的活度,促进PG脱水转晶及杂质脱除;EDTA-2Na中羧基基团与石膏晶体表面的Ca²⁺发生配位形成的配位离子层可调控无水CaSO₄晶体生长,修饰晶面。     

添加剂抑制CaSO4高温分解的TG-FTIR研究(Ⅰ)氧化物系列

固硫产物CaSO4在高温下易分解,导致钙基固硫剂在高温下固硫率急剧下降,限制了燃烧过程中固硫技术在工业锅炉中的应用,固硫产物的稳定性是影响高温固硫率的重要因素,采用TG—FTIR联用技术,在线测定了不同种类的添加剂对CaSO4高温热分解的影响规律,结果表明：分别添加一定比例的Al2O3,MgO和ZnO等氧化物对CaSO4晶体在高温下(1000℃～1450℃)的分解有明显的抑制作用。     

添加剂抑制CaSO4高温分解的TG-FTIR研究(Ⅱ)碳酸盐系列

如何提高固硫产物 Ca SO4高温的热稳定性 ,从而提高以钙基固硫剂为主固硫剂的高温固硫率 ,成为燃中固硫的关键问题 .采用 TG- FTIR联用技术 ,在线测定了各种碳酸盐添加剂对固硫产物 Ca SO4在高温下 ( 1 0 0 0℃～ 1 45 0℃ )热稳定性的影响规律 .结果表明 ,添加一定比例的Na2 CO3 ,Ba CO3 ,Sr CO3 和 Mg CO3 对固硫产物 Ca SO4晶体在高温下的分解有明显的抑制作用 .     

酸性废水体系中硫酸钙反应结晶过程研究(英文)

The present work focused on the recycle of the sulfate and the metal ions from acidic wastewater dis charged by nonferrous metallurgical industry. The effects of the temperature, the reactant concentration, the stirring speed and the metal ions on the reactive crystallization process of calcium sulfate between sulfuric acid and lime were systematically investigated. The morphology of the precipitated crystals evolved from plateletlike and nee dlelike shape to rodlike shape when the temperature was increased from 25 to 70 ℃. An increase in the agglom.     

添加剂抑制CaSO4高温分解的 TG-FTIR研究 (Ⅲ)固硫效果定性和定量分析

在氧化物系列高温固硫剂和碳酸盐系列高温固硫剂研究的基础上,利用TG-FTIR联用技术和ZCL自动定硫仪,把一定量的分析煤样与氧化物系列高温固硫剂和碳酸盐系列高温固硫剂分别以3∶1的Ca/S比充分混和,对燃煤的实际固硫效果进行了定性和定量检测.结果表明,两种系列固硫剂均使CaSO4高温分解推迟到1200℃以后,SrCO3在高温时的固硫率高达96.7%,而BaCO3也达92.2%.     

一种基于含噪时序结构独立元分析的过程监控方法(英文)

Conventional process monitoring method based on fast independent component analysis (FastICA) cannot take the ubiquitous measurement noises into account and may exhibit degraded monitoring performance under the adverse effects of the measurement noises. In this paper, a new process monitoring approach based on noisy time structure ICA (NoisyTSICA) is proposed to solve such problem. A NoisyTSICA algorithm which can consider the measurement noises explicitly is firstly developed to estimate the mixing matrix and extract the independent components (ICs). Subsequently, a monitoring statistic is built to detect process faults on the basis of the recur-sive kurtosis estimations of the dominant ICs. Lastly, a contribution plot for the monitoring statistic is constructed to identify the fault variables based on the sensitivity analysis. Simulation studies on the continuous stirred tank reactor system demonstrate that the proposed NoisyTSICA-based monitoring method outperforms the conven-tional FastICA-based monitoring method.     

基于Aspen Plus的气流床煤气化炉三段平衡模型(英文)

A three stage equilibrium model is developed for coal gasification in the Texaco type coal gasifiers based on Aspen Plus to calculate the composition of product gas, carbon conversion, and gasification temperature. The model is divided into three stages including pyrolysis and combustion stage, char gas reaction stage, and gas phase reaction stage. Part of the water produced in the pyrolysis and combustion stage is assumed to be involved in the second stage to react with the unburned carbon. Carbon conversion is then estimated in the second stage by steam participation ratio expressed as a function of temperature. And the gas product compositions are calculated from gas phase reactions in the third stage. The simulation results are consistent with published experimental data.     

氧基电解质La_(10-x)V_x(SiO_4)_6O_(3+x)的制备及性能测试(英文)

Apatite-lanthanum silicate has attracted considerable interest in recent years due to its high oxide ion conductivity.In this paper,V-doped samples La10-xVx(SiO4) 6O3+x(0≤x≤1.5) were prepared by sol-gel method and the influences of V-dopant content on calcining temperature and conductivity were reported.The samples were characterized by thermal analysis(TG-DSC) ,X-ray diffraction(XRD) and scanning electron micrograph(SEM) . The apatite was obtained at 800°C,a relatively low temperature in comparison to 1500°C with the conventional solid-state method.The ceramic pellets sintered at 1200°C for 5 h showed a higher relative density than La9.33Si6O26 pellets sintered at 1400°C for 20 h.The conductivities of samples were measured by electrochemical impedance spectroscopy.The conductivity was improved with the increase of V-dopant content on La site.     

基于CoFe2O4载氧体的生物质化学链气化反应特性

在热重分析仪和固定床反应器上对基于CoFe₂O₄载氧体的生物质化学链气化反应特性进行了研究,考察了载氧体与生物质质量比、水蒸气、反应温度对生物质化学链气化反应特性的影响,同时也对载氧体的循环反应性能进行了研究。通过XRD及SEM对新制备的和反应后的载氧体进行了表征。热重结果表明：CoFe₂O₄能够提供晶格氧,有效促进生物质气化。当CoFe₂O₄与生物质质量比为0.8,水蒸气体积分数为50%,温度为900 ℃时,气化反应效果最好。5次循环反应后,仍能获得较高品质的合成气,载氧体能够循环再生且未出现明显烧结团聚。     

基于符号有向图与定性趋势分析的化工过程故障诊断方法(英文)

In the past 30 years, signed directed graph (SDG), one of the qualitative simulation technologies, has been widely applied for chemical fault diagnosis. However, SDG based fault diagnosis, as any other qualitative method, has poor diagnostic resolution. In this paper, a new method that combines SDG with qualitative trend analysis (QTA) is presented to improve the resolution. In the method, a bidirectional inference algorithm based on assumption and verification is used to find all the possible fault causes and their corresponding consistent paths in the SDG model. Then an improved QTA algorithm is used to extract and analyze the trends of nodes on the consistent paths found in the previous step. New consistency rules based on qualitative trends are used to find the real causes from the candidate causes. The resolution can be improved. This method combines the completeness feature of SDG with the good diagnostic resolution feature of QTA. The implementation of SDG-QTA based fault diagnosis is done using the integrated SDG modeling, inference and post-processing software platform. Its application is illustrated on an atmospheric distillation tower unit of a simulation platform. The result shows its good applicability and efficiency.     

煤/钙基载氧体化学链燃烧操作参数分析

化学链燃烧作为一种新颖的燃烧技术,在化石燃料燃烧释放能量的同时能够有效分离CO2.今以CO2为气化剂气化煤炭,基于Aspen Plus流程模拟软件,研究了煤/钙基载氧体化学链燃烧过程.结果表明,以CO2为煤气化剂,各反应器含水分少,可减少热损失.CaSO4载氧体具有载氧能力大以及反应活性良好等优点.气化炉中CO+H2含量随二氧化碳煤比增大逐渐增加后下降;随温度升高其含量先增加,后趋于平稳.燃料反应器中CO2+H2O含量随载氧体煤比增大,呈现先增大后减小的趋势;随温度升高其含量逐渐下降.空气反应器中CaSO4含量随空载比增大先增加后趋于平稳,随温度升高其含量趋于平稳后下降.气化炉中硫化物和氮化物含量随温度升高而下降,而燃料反应器和空气反应器中硫化物含量随温度升高增加趋势明显,氮化物含量变化不明显.最后确定了关键反应器操作参数:气化炉的二氧化碳煤比为1.8;燃料反应器的载氧体煤比为4.5;空气反应器的空载比为10.5和三反应器的操作温度分别为950、1000和1100℃.     

Effect of Gasifying Medium on the Coal Chemical Looping Gasification with CaSO4 as Oxygen Carrier☆

The chemical looping gasification uses an oxygen carrier for solid fuel gasification by supplying insufficient lattice oxygen. The effect of gasifying medium on the coal chemical looping gasification w...     

废弃活性炭化学链气化制富氢合成气

以废弃活性炭为原料,以Fe4ATP6复合载氧体为载氧体,在间歇高温流化床中考察了废弃活性炭化学链气化制富氢合成气反应的较优条件及复合载氧体的循环反应特性。结果表明,Fe4ATP6复合载氧体具有提供晶格氧及催化气化的双重作用,显著提高了碳转化率,促进了废弃活性炭气化过程,反应活性良好。废弃活性炭化学链气化制富氢合成气的优化反应条件：900℃、水蒸气流量为0.25 g·min^-1、OC/C比为1。在上述条件下,碳转化率达92.15%,合成气产量达1.20 L·g^-1,其中H₂产量为1.09 L·g^-1,平均浓度为55.30%。10次循环实验表明Fe4ATP6复合载氧体的反应活性略有降低,通过SEM、XRD分析载氧体的表面形貌、物质组成发现,载氧体反应后结构变化较大,粒径减小,生成了无反应活性的硅酸铁。     

废弃咖啡渣化学链气化反应特性

利用溶胶-凝胶法制备了以Fe₂O₃为活性组分,天然凹凸棒土(ATP)为惰性载体,KNO₃修饰的Fe4ATP6K1铁基复合载氧体。在高温流化床中考察了反应温度、水蒸气流量和O/C摩尔比对咖啡渣化学链气化过程的影响。结果表明,与以石英砂为床料的咖啡渣气化相比,以Fe4ATP6K1载氧体为床料的咖啡渣化学链气化对应的碳转化率由71.38%提高到86.25%。咖啡渣化学链气化的较优操作条件为:反应温度900℃、水蒸气量0.23 g·min^-1、O/C摩尔比1;在此操作条件下,合成气产量达到1.30 m³·kg^-1,氢气产量达到83.79 g·kg^-1,氢气的平均浓度达到52.75%。通过X射线衍射(XRD)、扫描电镜-能谱(SEM-EDS)对900℃反应前后的Fe4ATP6K1进行表征,发现Fe相、K相、Si相可以发生相互作用,K以KFeSi₃O₈的形式存在于载氧体中,并且K在反应过程中有少量流失。20次氧化/还原过程中,铁基复合载氧体Fe4ATP6K1表现出较好的循环性能,碳转化率和冷煤气效率均保持在75%以上,各气体的平均浓度较稳定。     

基于铁基载氧体的煤化学链气化还原过程中氮元素迁移行为

采用热重-质谱-红外联用技术（TG-MS-FTIR）,Ar气氛下对煤进行化学链气化实验,实时分析还原过程热解阶段和水蒸气气化反应阶段的过程中固体质量变化和生成气体成分。使用X射线光电子能谱对固相产物进行表面元素分析,探究化学链气化还原过程不同阶段固相产物中氮赋存形态的变化。研究结果表明：载氧体对化学链气化还原过程不同阶段含氮气体释放均有影响。热解阶段载氧体促进自由基的生成,加速了一次热解阶段含氮气体的释放,高温下,载氧体促使NH₃转化为HCN;气化阶段载氧体的加入使半焦的石墨化程度降低,含氮气体释放速率增加。对固相产物中氮的赋存形态而言,载氧体会抑制热解阶段吡咯型氮的分解与转化,高温下,半焦的石墨化和有序化程度降低的同时,镶嵌在煤大分子里面的质子化吡啶裸露出来,质子化吡啶含量降低,吡啶型氮和吡咯型氮的含量大大提升。     

生物质化学链气化氧载体的研究进展

生物质化学链气化(chemical looping gasification, CLG)为生物质能源的利用开辟了新途径,氧载体在CLG过程中具有重要作用,其性能是影响CLG反应过程的关键因素。本文重点阐述了CLG技术中氧载体的性能评价指标、类型、制备方法及其对CLG过程中产生焦油的影响。通过对比分析目前研究成果,指出Fe基氧载体在生物质CLG过程中应用最广泛,而Ni基氧载体具有较高的活性和较大的载氧能力,且对于CLG副产物焦油具有较高的催化转化效率。未来该领域研究的重点方向是开发高活性且环境友好的氧载体,推进CLG工艺的工业应用。本文为今后生物质CLG氧载体的开发与优化提供了借鉴。     

钙基复合载氧体的制备及反应性能

采用湿式混合成粒法得到了一种复合型钙基载氧体,并分别在综合热分析仪和流化床上考察了其反应活性和循环反应性能。结果如下:浸渍Ni离子能够明显降低载氧体与煤反应的起始温度,加快反应速率,缩短反应时间。增加Ni离子浸渍量对反应速率的影响不明显,但反应时间略有缩短。选择CaAlNi10载氧体进行了10次还原-氧化循环实验,固体产物和气体产物分析表明NiO在循环过程中对S的释放有一定控制作用;CaAlNi载氧体具有较高的再生率和良好的持续循环反应能力。结果表明,制备的CaAlNi载氧体适用于工业生产。     

化学链燃烧中载氧体的研究进展

介绍了化学链燃烧的工艺原理和特点,总结载氧体的选材要求及性能,通过分析镍系、铁系、锰系、铜系和新型载氧体的性能,对以后载氧体的发展方向进行了展望。     

化学链燃烧中煤灰原位改性对钙基载氧体炭沉积的影响

在流化床中利用准东煤灰负载在钙基载氧体上,对钙基载氧体进行原位改性,从而制备改性的CaSO₄-Ash复合载氧体。借助TG-MS实验中的CO₂离子流量强度曲线,考察准东煤灰负载量对载氧体还原反应过程中炭沉积特性的影响规律,并通过固固反应与气固反应定量耦合实验,探究炭沉积的来源。结果表明：炭沉积量随原位改性制备过程中煤灰比例升高先减少后增加,添加质量分数为10%的准东煤灰制备的CaSO₄-10Ash复合载氧体能够最大程度降低炭沉积问题,减少了79.5%的炭沉积。固固反应中随煤灰负载比例升高,煤焦炭残留量减少,气固反应中煤灰负载比例大于5%时,复合载氧体性能开始呈下降趋势,积炭量开始增多;当煤灰负载比例大于10%时,随负载比例继续升高而增多的炭沉积的量主要来自于CO分解产生的积炭。