Experimental study on CO2 capture conditions of a fluidized bed limestone decomposition reactor

In this study, the decomposition conditions of limestone particles (0.25-0.50 mm) for CO₂ capture in a steam dilution atmosphere (20-100% steam in CO₂) were investigated by using a continuously operating fluidized bed reactor. The results show that the decomposition conversion of limestone increased with the steam dilution percentage in the CO₂ supply gas. At a bed temperature of 920 °C, the conversions were 72% without steam dilution and 98% with 60% steam dilution. The conversion was 99% with 100% steam dilution at 850 °C of the bed temperature. Steam dilution can decrease not only the decomposition temperature of limestone, but also the residence time required for nearly complete decomposition of CaCO₃. The hydration and carbonation reactivities of the CaO produced were also tested and the results show that both the reactivities increased with the steam dilution percentage for decomposing limestone.     

钙基CO_2吸收剂循环活性衰减原因初探

对钙基CO2吸收剂的循环活性衰减进行了实验研究,考察了随着循环次数的增加,吸收剂的表面形态、吸收剂分子孔径及比表面积等微观结构的变化,分析了钙基CO2吸收剂循环活性衰减的原因。结果表明,随着循环次数的增加,吸收剂晶粒中的片状结构已经完全消失,取而代之的是正方体状的大晶粒,晶粒生长严重,大量空隙被封闭。而由此引起的吸收剂的比表面积的不断减小和孔容积的降低以及孔分布的改变,导致了吸收剂循环活性的衰减,吸收剂的循环转化率降低。     

粉煤灰与炉底渣的蒸压反应活性研究

粉煤灰和炉底渣均为燃煤发电过程中产生的固体废弃物,但两者的反应活性有所区别。研究结果表明,炉底渣的玻璃相含量以及活性SiO2、Al2O3含量均高于粉煤灰,在蒸压条件下炉底渣的反应活性优于粉煤灰,有利于生成更多的水化产物。利用炉底渣部分或全部取代粉煤灰制备蒸压硅酸盐制品,有利于提高制品的强度。     

Wetting and interfacial reactions in liquid Au-Ti alloys / ZrO2 system

This study investigates wetting of zirconia by Au-Ti alloys containing 0.6–4 wt% Ti in view of brazing zirconia to titanium with pure gold for biomedical applications. Experiments were carried out using sessile and dispensed drop methods under high vacuum at 1040–1250 °C. Bulk drops and Au-Ti / ZrO₂ interfaces were characterized by SEM and FEG-SEM with EDXS analysis. While Au does not wet zirconia, the contact angle θ being ∼ 120°, the addition of Ti in Au leads to a significant improvement of wetting due to the formation of a wettable oxide layer at Au-Ti / ZrO₂ interface. The nature of this oxide was determined by X-ray diffraction of the reaction layer after the detachment of the droplet from the substrate or after the dissolution of the droplet. The mechanism of formation and growth of the oxide layer and its growth kinetics were determined based on fine analysis of the Au-Ti / oxide layer / ZrO₂ interfacial system.     

Enhancement reactivity of Bombyx mori silk fibroins via genipin-mediated grafting of a tyrosine-rich polypeptide

Bombyx mori silk fibroin has potential applications in the biomedical field owing to its satisfactory biocompatibility. In the present work, a tyrosine-rich polypeptide (P) with the sequence of GKGYGGYGK was grafted onto fibroin molecules using a natural cross-linking agent of genipin (GP), aiming at improving the reactivity of the fibroin-based materials. Incubation of the polypeptide-grafted fibroin membrane was subsequently carried out, with a mushroom tyrosinase (MT) and a model functional macromolecule of ε-poly-l-lysine (ε-PL). The changes in the structure and composition of the silk fibroin before and after polypeptide grafting were examined by means of size exclusion chromatography and amino acid analysis. The results indicated that the polypeptide was covalently bonded to fibroin chains and evidently promoted the succeeding enzymatic coupling of ε-PL with fibroins, resulting in a higher content of ε-PL compared to the control. The obtained antibacterial activities against S. aureus and E. coli for the fibroin membrane treated with GP/P and MT/ε-PL was more satisfactory than others. Cytotoxicity testing reveals that polypeptide grafting did less impact on the biocompatibility of silk fibroins. The present work provides a novel method to improve the reactivity of silk fibroins and it can be utilized for bio-functionalization of silk fibroin.     

非晶颗粒态马铃薯淀粉改性研究

将非晶颗粒态淀粉和原淀粉在阴离子、阳离子、醋酸酯及羟丙基醚化剂条件下进行淀粉改性反应,取代度随醚化剂量的改变而改变,但由于整个颗粒处于非晶状态,导致非晶淀粉取代度和原淀粉相比有不同程度的提高,对羧甲基化,取代度平均提高9.15%,最高达10.72%,对阳离子化来说,取代度平均提高9.65%,最高达13.18%,对醋酸酯化,取代度平均提高47.49%,最高达64.82%,对羟丙基化,取代度平均提高22.78%,最高达27.48%.     

EGR对生物柴油颗粒物氧化活性及微观结构的影响

为研究废气再循环(EGR)及燃用调合生物柴油(B0,B20)对柴油机排放颗粒物(PM)氧化活性与微观结构的影响,通过一台4缸共轨柴油机进行试验,并采集燃烧颗粒物,使用热重分析仪(TGA)、高倍透射电镜(HRTEM)和拉曼光谱(RS)对颗粒物进行研究.结果表明:燃用同种燃料时,随着EGR率增加,颗粒中干碳烟含量增加,起始氧化温度T_i上升,表观氧化活化能E逐渐增强,氧化活性降低;相比B0颗粒,B20颗粒中干碳烟含量略有减少,起始氧化温度T_i略有下降,E减弱,氧化活性增加.随着EGR率增加,颗粒物核-壳结构更为明显,当EGR率从0增至25%时,B0和B20颗粒初级碳粒子的平均微晶尺寸分别增加20%和25%,平均微晶曲率分别降低10%和7%,平均碳层间距分别降低5.8%和6.0%.同时,B0和B20颗粒的I_G/I_D增加,石墨化程度提高.     

硫杂质对焦反应性的影响及其机理(英文)

采用以低杂质沥青焦模拟石油焦和外掺杂的方式,研究硫杂质元素对焦反应性的影响,并通过XRD、SEM和EDS等检测手段探讨其作用机理。结果表明:在无其他杂质元素干扰的情况下,硫实际上是一种对焦的空气和CO2反应性都具有明显催化性的杂质元素。其催化作用可能是通过在焦的空气和CO2反应过程中分别引发有机硫→H2S→SO2→COS和单质硫(S x)→SO2和有机硫→H2S→COS→S x→C2S→COS两组可部分循环并具有增加碳耗和增大焦比表面积作用的反应体系来实现的。     

煤超分子结构及研究方法进展

为了进一步理解煤的超分子结构研究对于煤清洁和高效利用具有的理论价值和实际意义,对煤超分子结构及研究方法进行了综述。首先对煤超分子的概念及超分子结构之间的相互作用进行了介绍;然后阐述了煤超分子结构模型的研究方法及研究进展;最后对煤超分子结构和反应性能之间的关系进行了探讨,旨在为煤超分子结构的构建与反应性之间关系的研究提供参考,为进一步研究工作起到指导作用。