羧酸钠对五彩湾煤热解及煤焦热反应性的影响

针对准东煤中高含量有机钠对煤热解燃烧会产生不利影响的问题,通过向酸洗脱除碱金属后的五彩湾煤定向加载羧酸钠的方法,对比分析加钠煤和再次脱钠二次酸洗煤的热重曲线、气体产物及不同温度热解焦在低温下的热反应性,研究羧酸钠对五彩湾煤热解和焦反应活性的影响。结果表明:羧酸钠会显著促进五彩湾煤热解挥发分的释放及煤羧基官能团的热分解,在600℃以下抑制CO的生成,600℃以上时则相反,同时高温下会抑制脂肪侧链的分解及煤的缩聚反应;羧酸钠对煤焦的热反应性具有催化作用,主要由两条路径实现:在煤焦表面形成"C-O-Na"基团或钠团簇进行催化。     

煤焦异相还原NO的实验研究

在U形石英管固定床反应器中实验研究了乌达煤焦对NO的异相还原作用。乌达煤焦在程序升温和快速升温条件下还原NO的实验结果表明,反应温度超过700℃时,NO的还原率开始迅速上升,在实验范围内,温度维持在800～1 000℃,NO的还原率较高。反应区的初始氧气体积分数越高,NO的还原率越低,表明煤焦与氧气的反应和煤焦还原NO的反应之间存在着较强的竞争作用。煤焦粒径越粗、制焦温度越高,NO的还原率越低,表明制焦条件对煤焦还原NO的反应性亦有较大影响。     

湿法烟气脱硫石灰石的活性

为确定湿法烟气脱硫石灰石的活性,根据膜理论,建立了石灰石溶解模型．并通过定pH值滴定法考察了pH值、温度、粒径分布、石膏、飞灰、Al^3＋、F^-等因素对石灰石溶解过程的影响,试验数据同模型计算结果吻合较好．较低的pH值、较高的反应温度和较小的石灰石粒径有利于石灰石的溶解;石膏、飞灰、Al^3＋和F^-对石灰石的溶解有轻微的抑制作用;Al^3＋与F^-形成的络合物则会严重抑制石灰石的溶解．     

PHB/PET/VA三元共缩聚反应机理探讨

首次使用400MHz 高分辨氢核磁共振方法,依据 PHB/PET/VA 三元共聚酯的序列分布,较详细研究了 PHB/PET/VA(A/B/C)三元共缩聚反应机理,获得了一系列重要的单体竞聚率。竞聚率值表明,单体 VA(香草酸)易于均聚,而单体 PHB(对乙酰氧基苯甲酸)和单体 PET(聚对苯二甲酸乙二酯链节)都易于与单体 VA 共缩聚。     

城市污泥/褐煤共水热碳化产物的热化学转化特性及规律研究

污泥和褐煤通过共水热碳化预处理以制备高品质固体燃料,为污泥和低阶煤的有效处理提供了一种可行方案。本研究主要考察了城市污泥(SS)和褐煤(LC)在不同温度下(120,180,240和300℃)进行共水热碳化制得的固相产物(水热炭)的热化学转化特性和规律,包括燃烧、热解和半焦CO₂气化过程,并分析了这些过程中的协同作用。结果表明,共水热碳化预处理对城市污泥和褐煤的热利用行为有显著影响。一方面,共水热碳化处理后的水热炭相对其计算值具有更高的产率、煤化程度、热值等,同时具有更低的灰分含量。另一方面,混合物水热炭在燃烧、热解和半焦CO₂气化过程均表现出一定的协同作用(促进燃烧和热解行为,降低气化活性),且水热温度在240℃附近时,这种作用最为明显。鉴于热解和气化过程的协同效果均低于燃烧过程,共水热碳化产物被认为更适合用于燃烧。这些发现表明,将共水热碳化改性提质处理与后续热化学工艺相结合,对于能源的产生和有机废弃物的利用都有一定的积极意义。     

Dynamic simulation of a space gas-cooled reactor power system with a closed Brayton cycle

Space nuclear reactor power (SNRP) using a gas-cooled reactor (GCR) and a closed Brayton cycle (CBC) is the ideal choice for future high-power space missions. To investigate the safety characteristics and develop the control strategies for gas-cooled SNRP, transient models for GCR, energy conversion unit, pipes, heat exchangers, pump and heat pipe radiator are established and a system analysis code is developed in this paper. Then, analyses of several operation conditions are performed using this code. In full-power steady-state operation, the core hot spot of 1293 K occurs near the upper part of the core. If 0.4 $ reactivity is introduced into the core, the maximum temperature that the fuel can reach is 2059 K, which is 914 K lower than the fuel melting point. The system finally has the ability to achieve a new steady-state with a higher reactor power. When the GCR is shut down in an emergency, the residual heat of the reactor can be removed through the conduction of the core and radiation heat transfer. The results indicate that the designed GCR is inherently safe owing to its negative reactivity feedback and passive decay heat removal. This paper may provide valuable references for safety design and analysis of the gas-cooled SNRP coupled with CBC.     

Virtual Vibrational Analytics of Reduced Graphene Oxide

The digital twin concept lays the foundation of the virtual vibrational analytics suggested in the current paper. The latter presents extended virtual experiments aimed at determining the specific features of the optical spectra of the studied molecules that provide reliable express analysis of the body spatial structure and chemical content. Reduced graphene oxide was selected as the virtual experiment goal. A set of nanosize necklaced graphene molecules, based on the same graphene domain but differing by the necklace contents, were selected as the relevant DTs. As shown, the Raman spectra signatures contained information concerning the spatial structure of the graphene domains, while the molecule necklaces were responsible for the IR spectra. Suggested sets of general frequency kits facilitate the detailed chemical analysis. Express analysis of a shungite carbon, composed of rGO basic structural units, revealed the high ability of the approach.     

相渗透率改善剂P（MPEGMA-DMAEMA）的合成及溶液性质

以甲氧基聚乙二醇甲基丙烯酸酯（MPEGMA）和甲基丙烯酸二甲氨基乙酯（DMAEMA）为单体,以AIBA/NaHSO-3NH4S2O8为复合引发剂,采用反相微乳液法合成了一种疏水缔合型共聚物。利用红外光谱分析证实了共聚物的结构,并用F-R法求得DMAEMA和MPEGMA的竞聚率分别为r1=0.32,r2=1.52。此外,...     

酚单体反应活性与苯环碳原子化学位移的关系

从各种酚单体,尤其是无其他取代基酚单体和甲基酚单体苯环碳原子化学位移出发,探讨酚单体取代基共轭效应参数Rc和酚单体在合成酚醛树脂时反应活性之间的关系。一般而言,Rc越大,活性点的化学位移越小,酚单体的反应活性越高。同一类酚单体中,酚羟基互位于间位时,或其他取代基位于酚羟基间位时,Rc最大,反应活性最高。在电荷控制机制的反应中,化学位移是预测和判断酚单体反应活性的主要依据,合成酚醛树脂时酚单体的反应活性又受取代基空间位阻、催化剂、溶剂和反应温度等因素的影响。