高温下钙基吸附剂吸附CO2的研究

CaO基吸附剂是一种理想的CO2高温吸附剂。利用热重分析仪研究了由不同前体制备的CaO高温下对CO2的吸附性能。利用吸附仪测定了各吸附剂的比表面积等参数。实验发现CaO的最佳吸附温度范围为700—750℃;由CaC2O4.H2O制得的CaC2O4-CaO具有良好的吸附性能,在实验条件下,其吸附量为理论吸附量的89.1%;在较宽的CO2体积分数范围内,CaC2O4-CaO始终保持很高的吸附性能;吸收速率的大小受吸附剂比表面积、孔体积、孔结构等参数的共同影响。高温下,CaO基吸附剂吸附CO2的微观机理有待进一步研究。     

Electrochemical CO2 Reduction: Recent Advances and Current Trends

With rising levels of CO₂ in our atmosphere, technologies capable of converting CO₂ into useful products have become more valuable. The field of electrochemical CO₂ reduction is reviewed here, with sections on mechanism, formate (formic acid) production, carbon monoxide production, reduction to higher products (methanol, methane, etc.), use of flow cells, high pressure approaches, molecular catalysts, non-aqueous electrolytes, and solid oxide electrolysis cells. These diverse approaches to electrochemical CO₂ reduction are compared and contrasted, emphasizing potential processes that would be feasible for large-scale use. Although the focus is on recent reports, highlights of older reports are also included due to their important contributions to the field, particularly for high-rate electrolysis.     

微生物电解池辅助CO2甲烷化阴极材料的研究进展

微生物电解池（microbial electrolysis cell,MEC）产甲烷技术是一种有望成为缓解能源危机与温室效应的重要新型途径。它以外界输入的较小电能为能量来源,以微生物为催化剂,在阳极通过分解有机物形成电子和质子;在阴极产生氢气和甲烷。近年来,MEC在反应器构型、阴极材料设计及电子转移途径、微生物群落结构组成等方面的研究取得了重要进展,寻找高效低价的阴极材料催化剂,实现MEC从概念到应用成为相关领域的研究热点。本文综述了MEC耦合厌氧消化系统产甲烷的工作原理和常见阴极材料的发展现状;分别对碳基阴极、金属基阴极及复合阴极的甲烷产率进行了阐述;系统介绍了不同阴极系统的电子传递方式、电化学特性、生物相容性、微生物群落结构组成等属性;讨论了各类电极的优缺点,并指出了今后的重点研究方向,以期为MEC耦合厌氧消化产甲烷技术的工程应用提供基础。     

Chemical reactivity of CO and CO2 at a Cu(110)-Cs surface

Carbon dioxide and carbon monoxide undergo reactive chemisorption with cesium modified Cu(110) and Cu(110)-O surfaces and via the anionic intermediate CO ₂ ^– (a) form a surface carbonate. The CO ₂ ^– (a) species was characterised by VEELS and XPS at low temperature (80 K) and the surface carbonate at 295 K. For cesium modified Cu(110) surfaces chemisorption of carbon monoxide gives rise to electron energy loss peaks (v _co) as low as 1450 cm^–1 at 295 K.     

碳酸钾一乙醇胺复合溶液吸收烟气中C02的实验研究

分别以不同浓度的碳酸钾溶液及不同配比的碳酸钾一乙醇胺复合溶液作为吸收剂,以吸收速率和吸收量为指标,研究了吸收剂对烟气中C02的吸收效果。结果表明,纯碳酸钾溶液吸收效果不佳,而掺入乙醇胺后的吸收效果显著改善,部分复合溶液的吸收效果甚至好于同浓度纯碳酸钾溶液与纯乙醇胺溶液的吸收效果之和,碳酸钾与乙醇胺在吸收过程中存在正交互作用。确定0．6mol·L-1碳酸钾-O．4mol·L-1乙醇胺复合溶液为最佳的吸收弃1,其饱和吸收量最大（O．185m01）、再生温度最低（105℃）、再生率最高（98．8％）。     

Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of CO2 in H2-mediated microbial electrosynthesis

Microbial electrosynthesis is a promising alternative to directly convert CO₂ into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic systems. However, problems arose that the conventional electrocatalysts for hydrogen evolution may produce extensive by-products of reactive oxygen species and cause severe metal leaching, both of which induce strong toxicity toward microorganisms. Moreover, poor stability of electrocatalysts cannot be qualified for long-term operation. These problems may result in poor biocompatibility between electrocatalysts and microorganisms. To solve the bottleneck problem, Co anchored on porphyrinic triazine-based frameworks was synthesized as the electrocatalyst for hydrogen evolution and further coupled with Cupriavidus necator H16. It showed high selectivity for a four-electron pathway of oxygen reduction reaction and low production of reactive oxygen species, owing to the synergistic effect of Co–N_x modulating the charge distribution and adsorption energy of intermediates. Additionally, low metal leaching and excellent stability were observed, which may be attributed to low content of Co and the stabilizing effect of metalloporphyrins. Hence, the electrocatalyst exhibited excellent biocompatibility. Finally, the microbial electrosynthesis system equipped with the electrocatalyst successfully converted CO₂ to poly-β-hydroxybutyrate. This work drew up a novel strategy for enhancing the biocompatibility of electrocatalysts in microbial electrosynthesis system.     

甲烷化抑制剂在微生物电化学合成乙酸系统中的生物抑制效应

研究了利用2-溴乙烷磺酸钠(BES)选择性抑制产甲烷菌,从而提高微生物电化学系统合成乙酸产率的可行性,并对比了BES添加前后阴极室微生物菌群结构的变化。结果表明,厌氧混合菌接种物未经BES处理时甲烷是电化学系统CO₂还原的主导产物,最大生成速率达0.95 mmol·L^-1·d^-1,8 d反应时间甲烷中电子回收率达55.0%,16S rRNA测序结果显示固态阴极的主要菌群为Methanobacteriaceae。BES的添加基本抑制了产甲烷菌的活动,使得乙酸成为主导产物,其合成速率最高达2.22 mmol·L^-1·d^-1,系统总电子回收率达67.3%。Rhodocyclaceae (15.1%),Clostridiaceae(11.9%)、Comamonadaceae(11.1%)和Sphingobacteriales(11.0%)为主要菌群。研究结果表明了微生物电化学合成系统中抑制甲烷生成对调控微生态结构,从而调控电化学终产物的重要性。     

2-甲基咪唑/乙二醇体系常温脱除天然气中的二氧化碳

将2-甲基咪唑溶于乙二醇中形成混合溶液体系,利用该体系常温下实现对天然气中二氧化碳的脱除。首先分别测定单组分甲烷和二氧化碳在体系中的吸收容量,在0.1 MPa下,CO₂在2-甲基咪唑/乙二醇混合溶液中溶解度约为0.87 mol·L^-1,高于同等条件下CO₂在大部分离子液体中的溶解度,二氧化碳的吸收容量远大于甲烷的;然后对混合气CH₄/CO₂进行分离,发现该体系能较好吸收分离CH₄/CO₂。最后考察了体系的再生性和重复利用性,得出2-甲基咪唑/乙二醇溶液体系能完全再生并且能重复使用。     

煤焦在气化合成气中高温气化反应特性

在固定床管式炉反应器中进行了煤焦在H₂O、CO₂、H₂和CO混合气氛中气化特性的实验研究,考察了反应温度、原料气组成和加煤量对产物气组成以及碳转化率的影响。实验结果表明,在各实验条件下,合成气与煤焦反应后CO流量均增加最多,H₂少量增加。煤焦与CO₂的反应受到明显抑制。混合气体通过与煤焦反应可以提高有效气（CO+H₂）的含量,实验条件下反应出口气体中有效气浓度比反应结束时最多提高3.3个百分点。反应速率受气化剂之间的竞争和气化产物的抑制作用较为明显,在1100℃和1300℃时,煤焦在相同气化剂流量的合成气中的最高反应速率分别只有在纯气化剂（水蒸气或CO₂）中最高反应速率的49%和69%。受到多种气体组分之间的相互影响,气体在孔道里的扩散和吸附对反应影响更加显著,随机孔模型可以较好地拟合此类反应,而不考虑孔结构的均相模型和缩芯模型拟合度较差。     

Anaerobic CO2 fixation by the acetogenic bacterium Moorella thermoacetica

Anaerobic bacteria such as Moorella thermoacetica have the capacity of fixing carbon dioxide with carbon monoxide and hydrogen for the production of ethanol, acetic acid, and other useful chemicals. In this study, we evaluated the fixation of CO₂ for the production of acetic acid, as a product in its own right but also as precursor for lipid synthesis by oleaginous organisms. We achieved maximum cell optical density of 11.3, acetic acid titer of 31 g/L, and productivity of 0.55 g/L‐h at CO mass‐transfer rate of 83 mM/h. We also showed electron availability by CO mass transfer limited the process at CO mass transfer rates lower than 30 mM/h. Further enhancement of mass‐transfer rate removed such limitations in favor of biological kinetics as main limitation. This work underlines the potential of microbial processes for converting syngas to fuel and chemical products in processes suitable for distributed feedstock utilization. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3176–3183, 2013     

新型超临界水中煤气化制氢产物的CO2分离过程

目前CO₂的分离方式主要局限在常压条件下,在高压条件下分离CO₂的研究鲜有报道。本文为了解决这一问题,针对煤在超临界水中气化过程压力高的特点,构建了高压水吸收法分离CO₂系统,建立了高压多组分气液相平衡的能量分析模型和 分析模型;并对CO₂的分离过程进行分析,获得了高压吸收器中压力对各种气体产物摩尔分数和液相中气体吸收率的影响规律;针对高压水吸收法分离CO₂的流程,建立了CO₂分离过程中的能量分析模型和 分析模型,得到了高压吸收器中压力发生变化时,CO₂分离过程的能量效率、 效率以及CO₂分离能耗的变化规律,为超临界水中煤气化制氢新技术中分离器的设计提供了依据。     

石膏在高温下的分解脱硫研究

高效经济脱硫是脱硫石膏以氧化钙化学循环和烟气制酸途径实现资源化利用的关键。通过热重-质谱（TG-MS）联用、管式炉焙烧实验，并借助XRD、XRF等检测分析手段，系统研究了碳含量、氧化铁含量及温度对石膏分解和脱硫率的影响。结果表明，在氩气气氛下，石膏中加入碳和氧化铁均能有效降低石膏的分解温度，提高石膏的分解速率。碳含量、氧化铁含量、焙烧温度对石膏分解具有不同作用区间。高温低配碳时，石膏的分解率和脱硫率最高，当温度超过1 200 ℃时，升温对提高脱硫率的作用逐渐消失。配碳量增加后，脱硫率和分解率明显下降，分解温度降低，完全反应时间减少；添加氧化铁后，石膏的分解温度下降，分解率和脱硫率上升。实验条件下，为提高脱硫率，获得更多的氧化钙，控制温度在1 100 ℃，碳与硫酸钙物质的量比为0.8，氧化铁添加量为10%。     

高浓度CO2碳解强化碳碱法制取硼砂

本文针对目前我国碳碱法制取硼砂存在的碳解时间长、设备生产效率低、硼矿的分解率低,造成硼收率低的问题,提出了用高浓度ＣＯ２进行碳解强化碳碱法工艺的技术途径,进行了新老工艺技术经济对比,并介绍了凤城矿翁泉沟硼铁矿配套浓ＣＯ２碳解新工艺碳解反应釜的设计以及高浓度ＣＯ２来源和富集提浓方法。     

改性活性炭吸附脱除二氧化碳中微量乙烷

我国对食品级二氧化碳要求较高,在其生产过程中乙烷的脱除是难点。文章首先考察了市售的不同吸附剂,包括Y型、X型、A型等分子筛类,椰壳和煤基活性炭以及吸附树脂等吸附剂对CO2中微量C2H6的吸附效果,之后考察了不同浓度盐酸酸改性与氢氧化钠碱改性、双氧水氧化改性、氨水还原改性等改性条件对吸附剂吸附性能的影响。研究表明,具有高比表面积、丰富微孔和适量中孔结构的活性炭更有益于二氧化碳中微量乙烷的吸附;浓度为1%的盐酸溶液浸渍活性炭3 h后,能增强其对CO2中微量C2H6的吸附能力;浓度3%、浸渍时间6 h为氢氧化钠碱溶液改性活性炭的最佳条件;弱氧化剂双氧水改性能略微提高活性炭对二氧化碳中乙烷的吸附能力,弱还原剂氨水改性对吸附效果无明显影响。     

二氧化碳法制备六亚甲基二异氰酸酯的研究

研究了二氧化碳与己二胺甲氧羰基化反应合成六亚甲基二异氰酸酯，考察了有机碱用量、反应温度、反应时间和压力等操作条件对反应的影响。结果表明最佳工艺条件：n（三乙胺）：n（己二胺）=3：1，反应温度-5℃、反应时间60min、压力为0．55MPa。并用红外谱图和折光率对合成产物进行表征。     

高压法三聚氰胺装置与二氧化碳汽提法尿素装置联产利弊浅析

中国石油乌鲁木齐石化分公司化工厂高压法三胺装置由于配套小尿素装置甲铵预热器爆管损坏无法开车,且装置原设计运行不平稳、检修频率高、能耗高。鉴于这些原因,三胺装置和化肥尿素装置同时改造,两套装置原料互供,实现了高压法三胺装置和二氧化碳汽提法大尿素联产,大大降低运行能耗和原料损耗。     

Extrusion with Carbon Dioxide (CO2) and Characterization of ABS/Mg (OH)2/Nanoclay Composites

In this paper, carbon dioxide (CO₂) is used to form a high-density microcellular thermoplastic foam structure in order to reduce polymer consumption and facilitate dispersion of Mg (OH)₂ and nanoclay fillers. A twin-screw extruder system was used to predistribute inorganic fillers into the ABS polymer, resulting in composite ABS/filler pellets. This is followed by the use of a single-screw extruder wherein supercritical carbon dioxide is introduced into the formulation. Finally, the resulting foam ABS/filler/CO₂ pellets are injection- molded into test samples. The structure and properties of the composites are characterized using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Furthermore, ABS/Mg(OH)₂/nanoclay polymer composite samples are tested to obtain their yield and tensile strengths, elastic moduli, yield and tensile elongations, izod impact strengths, hardness values, heat deflection temperatures (HDT), Vicat softening points, and melt flow indices (MFI). These tests reveal that for the overall reduction in the amount of polymer in the samples, material properties did not generally deteriorate and even showed improvements in some areas. Moreover, resulting injection-molded samples have been shown to possess dimensional integrity due to the continued expansion of CO₂ during the molding operation.