O2/N2和O2/CO2气氛下煤半焦-生物质的混燃特性及影响因素

为掌握煤半焦与生物质在O₂/N₂和O₂/CO₂条件下的混燃特性及其影响因素,采用全自动物理化学吸附仪获得了煤半焦-生物质混合燃料的孔隙结构,采用热重实验分析了两种燃料的混燃特性和反应动力学,通过多元线性回归法研究了燃料比、比表面积与混燃特性参数之间的关系。结果表明,O₂/N₂气氛下,掺混生物质可改善煤半焦的着火、燃尽及综合燃烧特性;O₂/CO₂气氛下,掺混生物质能改善煤半焦的着火特性,但会延迟其燃尽。混燃的活化能在低温区和高温区有显著差异,生物质掺混比增大,两个温区的活化能都降低;两种气氛下,低温区的活化能相近,但O₂/CO₂气氛下高温区的活化能显著高于O₂/N₂气氛下的。O₂/N₂气氛下孔隙结构对燃烧特性的影响更显著,而O₂/CO₂气氛下...     

凹凸棒石负载有机胺用于沼气提纯的优化制备研究

凹凸棒石原矿吸附剂对CO₂的吸附量较低,不利于其在沼气提纯中的实际应用。因此,如何有效提高凹凸棒石的CO₂捕集能力是未来的研究重点。通过对凹凸棒石原矿进行酸改性处理,考察酸浓度和酸化时间对凹凸棒石组成、结构和性能的影响,采用扫描电镜（SEM）、X射线荧光光谱（XRF）、X射线衍射（XRD）和N₂吸附/脱附等手段进行表征。结果表明,在硫酸浓度为3 mol/L、酸化时间为72 h的条件下,所得到的凹凸棒石基无定型SiO₂（α-SiO₂）具有较高的比表面积和孔容并具有丰富的表面Si‒OH基团,其负载聚乙烯亚胺的CO₂吸附量达到3.21 mmol/g。这是由于酸改性去除了凹凸棒石层间杂质以及金属阳离子氧化物,从而改善了凹凸棒石的结构和性能,使氨基活性位点得到均匀地分散,提高了对CO₂的捕集性能。     

活化过程对呼图壁煤制备活性炭性能影响研究

以新疆呼图壁煤为原料制备活性炭,研究不同活化过程对活性炭性能的影响。根据煤样热重分析结果设计炭化过程,以制备优质炭化料,然后选择在不同活化过程下制得活性炭。试验结果表明,呼图壁煤制备的活性炭吸附性能及孔隙结构均较为优良,H₂O(g)活化温度的降低有利于制得吸附性能、孔容积与比表面积均较高的活性炭,而高温H₂O(g)活化可得到微孔孔径更为细小的活性炭。相比H₂O(g)活化,CO₂活化有利于制得综合性能更为优良的活性炭。KNO₃催化活化可显著减少活化时间,但不利于制得孔隙结构发达的活性炭。     

碳酸盐中CO2气化生物质制合成气

以杉木屑为原料,CO₂为气化剂,熔融碳酸盐Li2CO3-Na2CO3-K2CO3(LNK)为热介质和催化剂进行气化制合成气(H2+CO)的研究,考察气化剂CO₂流量、CO₂通入方式、复合熔盐体系中添加的金属氧化物种类和Cr2O3含量等因素对气体产物组成分布及产率的影响。结果表明:CO₂流量显著影响气化反应的平衡;以鼓泡法通入CO₂时生物质的气化效果优于吹扫法的情况,CO₂流量为99.8 L/h时气化效果较好,合成气含量和产率分别达到61.4%和350.2 mL/g生物质;添加的金属氧化物中Cr₂O₃对生物质气化过程的促进作用优于MgO和Fe₂O₃,随着Cr₂O₃含量的增大,合成气含量先增大后略微减小,在Cr₂O₃含量为10.0%时最高,为67.9%。     

联合CO2捕集的生物质化学链气化制备合成气系统分析

本文提出以Fe₂O₃为载氧体、以CaO捕集CO₂的生物质化学链气化系统,利用Aspen Plus软件对该系统进行了模拟,以合成气组成（干基）、合成气氢碳比、含碳产物的碳摩尔分布、冷气效率及收率等为系统性能评价指标,重点分析了燃料反应器温度（T_FR）、载氧体Fe₂O₃与生物质碳摩尔比（Fe₂O₃/C）、水蒸气与生物质碳摩尔比（Steam/C）、CaO与生物质碳摩尔比（CaO/C）等系统参数对固体生物质化学链气化系统的影响。结果表明,在T_FR = 825℃、Fe₂O₃/C = 0.5、Steam/C = 0.71和CaO/C = 0.26条件下,合成气制备系统性能较优,合成气中H₂和CO₂含量分别为55.2%和15.4%,氢碳比为1.93,冷气效率为78.2%,被CaCO₃捕集的生物质碳为18.2%,收率（湿气基）为1.95 Nm³/kg_biomass,其中合成气中H₂和CO收率为1.24 Nm³/kg_biomass。     

CO2/O2环境对柴油着火及燃烧特性的影响

为研究CO₂/O₂环境对柴油着火和燃烧特性的影响,以正庚烷为柴油表征燃料,利用CONVERGE计算了不同CO₂/O₂环境下正庚烷的着火和燃烧过程,并搭建了可视化定容燃烧弹试验平台进行了验证。使用高速摄影机记录了初始温度850 K,初始压力3 MPa,CO₂体积分数分别为35%、40%、50%和60%时正庚烷燃烧的自发光强度,利用CHEMKIN中定容均质反应器分析了CO₂物理和化学作用对着火的影响。研究结果表明：在CO₂体积分数35%时存在爆燃的现象,随着CO₂体积分数增长,着火延迟时间增长,着火位置远离喷嘴,稳态燃烧阶段火焰的长度和宽度也增大,CO₂体积分数在50%～60%之间时火焰自发光强度峰值明显下降;CO₂的物理作用抑制了着火,第三体作用对着火的促进作用大于直接参与反应对着火的抑制作用,造成CO₂的化学作用缩短了着火延迟时间,并且随着CO     

下吸式固定床的生物质H2O/CO2气化数值模拟研究

利用Aspen Plus 软件建立干桦木屑在下吸式固定床气化炉中的气化模型,模拟值与文献实验值吻合良好。利用Aspen Plus的灵敏度分析模块模拟分别以水蒸气（H₂O）和二氧化碳（CO₂）为气化剂时气化剂/生物质碳比（GC值）对气化结果的影响,并结合H₂O、CO₂各自的特点研究其复合气化。结果表明,H₂O气化时可获得富氢煤气,但其净CO₂排放量较高;CO₂气化时碳转化率及冷煤气效率较低,但净CO₂排放量较低;H₂O、CO₂复合气化使碳转化率及冷煤气效率略有降低,但可有效减少气化系统中的净CO₂排放量。     

炭化活化温度对活性炭-CaCl2复合吸附剂性能的影响

为研究并开发高性能的吸附剂,本文以CaCl₂和杉木木屑为原料,采用炭化活化造孔的方法制备复合吸附剂,考察了炭化活化温度对复合吸附剂性能的影响,炭化活化温度分别选择400℃、500℃、600℃和700℃。扫描电镜照片和元素分布图表明,复合吸附剂具有发达的孔隙结构而且CaCl₂分布均匀。NH₃吸附性能实验表明,吸附剂4 h的NH₃吸附量随炭化活化温度的升高而增加。而对于吸附制冷而言,500℃炭化活化温度下制备的复合吸附剂具有最好的性能,其30 min的吸附量达到0.488 g/g。     

梨木炭蒸汽气化制取富氢燃气的试验研究

生物质气化技术已得到广泛的应用,但气化过程产生的焦油会影响设备稳定运行。为了大幅减少焦油的干扰,以梨木的热解炭为原料,在管式炉中进行水蒸气气化制取富氢燃气试验研究,探究了反应温度、K₂CO₃添加量及利用次数对气化特性的影响。结果表明：900℃时H₂的产气量为2.19 L/g,合成气中H₂含量超过58%;K₂CO₃添加量为10%时产气效果最佳,此时合成气中H₂+CO含量达到了88.5%。当K₂CO₃催化剂在第三次利用时,仍有较好的催化效果。     

新型人工光合作用系统的能量和质量平衡研究

该文提出一种新型人工光合作用（AP）系统,通过PV/T装置将太阳能光热综合利用,转化为热能和电能,分别供给吸附式碳捕获和碳还原的反应过程。建立并耦合PV/T模型、吸附碳捕获与碳还原反应模型,随后基于CO₂还原反应所需的CO₂质量进行能量-质量匹配性分析。结果表明,金属有机骨架74（MOF-74）的CO₂捕获量比活性炭大了6倍,具有较大的CO₂捕获潜力,但当MOF-74吸附剂的质量高于50 kg时,CO₂捕获的热效率降低到20%以下。采用聚光度为10的1 m²的PV/T时,15 kg的MOF-74可在一天内捕获0.45 kg的纯CO₂,并制备0.152 kg甲烷。     

活化剂种类对生物质活性炭理化特性的影响

采用KOH、K2CO3和ZnCl2为活化剂,椰壳、竹子、杨木和棉秆为原材料制备活性炭,研究不同活化剂对生物质热解活化产物及活性炭理化特性的影响.结果表明,KOH活化时,生物质的固液气三相比例均衡,CO体积产量最高,活性炭的表面官能团稳定性最好,骨架破碎,微孔结构发达,微孔面积可达749.90 m2/g.K2CO3活化时...     

Hydrogen production by biomass gasification in supercritical or subcritical water with Raney-Ni and other catalysts

Gasification of peanut shell, sawdust and straw in supercritical or subcritical water has been studied in a batch reactor with the presence of a series of Raney-Ni and its mixture with ZnCl₂ or Ca(OH)₂. The main gas products were hydrogen, methane, carbon dioxide, and a small amount of carbon monoxide. Different types of Raney-Ni, containing different metal components such as Fe, Mo or Cr, have different influences on the gasification yield and hydrogen selectivity. The catalysis effect can be improved obviously by adding ZnCl₂ or Ca(OH)₂. Increasing the reaction temperature or adding ZnCl₂ and Ca(OH)₂ could improve the mass of H₂ in gas products and reduce the mass of CH₄ and CO₂ at the same time. The possible mechanism is that ZnCl₂ can decompose the biomass particle by accelerating cellulose hydrolyzation in high-temperature water, increasing more specific surface to admit catalysts, while Ca(OH)₂ can absorb CO₂ to produce CaCO₃ deposit, which can drop out from the reactant system, and which will drive the reaction to get more hydrogen. With respect to the biomass conversion to gas product and selectivity of H₂ at low temperature, the series of Raney-Ni has shown many advantages over other catalysts; thus, this kind of catalyst has great potential to be utilized in the hydrogen industry for the gasification of biomass.     

Preparation of activated carbon from rockrose char. influence of activation temperature

The influence of the activation temperature on textural characteristics of activated carbon prepared by partial gasification of a carbonized product (C-600) from rockrose wood (Cistus ladaniferus L.) was studied. Activations were effected in air, CO₂, and steam. The temperature ranged between 450° and 750°C in air and between 750° and 950°C in CO₂ or steam. Burnoff was 40%. Techniques used in the characterization study of the samples were gas adsorption (N₂, 77K; CO₂, 298K), mercury porosimetry, and density measurements. As temperature was increased, the microporosity increased for activations of C-600 in air, whereas the macroporosity decreased in CO₂ and in steam. The development of mesoporosity was greater when activating in steam at the lowest temperature. The product of steam activation at 750°C had the best textural characteristics.     

Hierarchically porous carbon from biomass tar as sustainable electrode material for high-performance supercapacitors

The byproduct tar from biomass gasification process had seriously impeded development and applications of this technology, thus novel path for biomass tar valorization is had been continuously pursued. Given its high carbon content, this work attempted to convert biomass tar into hierarchically porous carbon by thermal activation with acetate potassium. The optimal product produced with mass ratio of biomass tar to acetate potassium of 1:3 and activation temperature at 800 °C was revealed as excellent electrode material for high-performance supercapacitor, which demonstrated electrochemical capacitance up to 310.4 F/g at 0.2 A/g, whilst preserved 91% of initial capacitance after 5000 charge-discharge circles at current density of 5 A/g. These excellent properties had arisen from the open and hierarchical porosity and large surface area. This work disclosed the great potential of biomass tar as sustainable and competent candidate for fabricating high-performance electrode material for electrochemical energy devices, and may bring up new opportunities to development of biomass gasification technologies.     

广东能源消费碳排放趋势与前景展望

能源消费是人类活动排放CO₂等温室气体的主要来源,碳减排已成为我国能源发展的一个重要约束因素。2012年全世界能源消费排放3.173 4×1010 t CO₂,中国能源消费排放的CO₂已占世界总排放量的26.0%。2012年全世界人均CO₂排放量4 510 kg,而中国人均CO₂排放量达到了6 093 kg。同年广东省人均CO₂排放量为5 224 kg,高于世界平均水平,低于全国平均水平。随着节能减排和应对气候变化工作的推进,广东的单位产值能耗水平逐年降低,能源结构不断改善,使得全省化石能源消费带来的CO₂排放量的增长势头得到抑制,2012年的排放量比2011年略有减少。按目前的发展趋势预测,到2020年,广东CO₂排放总量将达到1.606 2×108 t碳当量,比2012年增加9.69×106 t碳当量,人均CO₂排放量将达到5 287 kg,略高于2012年的5 224 kg。如果在“十三五”期间加快第三产业发展,则到2020年广东省化石能源消费总量将比2012年下降2.7%,CO₂排放总量将比2012年下降3.5%,人均CO₂排放量将由2012年的5 224 kg下降到2020年的4 795 kg,接近世界平均水平。     

High quality H2-rich syngas production from pyrolysis-gasification of biomass and plastic wastes by Ni–Fe@Nanofibers/Porous carbon catalyst

To produce the high quality H₂-rich syngas from biomass and plastic wastes, a two-stage pyrolysis-gasification system involving pyrolysis and catalytic gasification is considered as a suitable route. Generally, synthesis of highly active, low cost and coke-resistant catalyst for tar cracking is the key factor. A series of monometallic catalysts of Ni@CNF/PCs and Fe@CNF/PCs and the bimetallic Ni–Fe@CNF/PCs catalyst were prepared by a simple one-step pyrolysis approach for high quality syngas production from pyrolysis-gasification of biomass and plastic wastes. The results indicated that the bimetallic Ni–Fe@CNF/PCs catalyst appeared as the optimal catalyst in affording the best compromise between catalytic activity and stability with the existence of the excellent dispersibility of the Fe0.64Ni0.36 alloy nanoparticles and the carbon nanofibers/porous carbon composite structure. In addition, the optimal operation conditions of biomass/plastic ratio of 1/2 and gasification temperature of 700 °C were observed for the bimetallic Ni–Fe@CNF/PCs catalyst to play best roles in the H₂-rich syngas quality, with up to 33.66 mmol H₂/g biomass, and tar yields as low as 5.66 mg/g.     

One-pot synthesis of high N-doped porous carbons derived from a N-rich oil palm biomass residue in low temperature for CO2 capture

Porous carbon materials have been widely used for CO₂ adsorption, but their preparation was subject to conditions such as raw material cost, activator corrosion, and temperature. In this study, nitrogen-doped porous carbonaceous adsorbents were prepared in a low temperature region (400-550°C) by one-step composite nitrogen doping method, using low-cost oil residue as raw materials and less corrosive NaNH₂ as activator. The CO₂ adsorption performances of the prepared N-doped porous adsorbents were systematically explored. The results showed that optimal oil residue-derived carbonaceous adsorbent owned excellent amount of CO₂ adsorption up to 3.51 and 5.63 mmol/g at 298 and 273 K under 1 bar, respectively. It was discovered that the congenerous influences of porous structure, nitrogen content and V_n of the adsorbent affected their CO₂ adsorption performances under 1 bar. Importantly, these oil residue porous carbonaceous adsorbent also was verified owning fine selectivity of the CO₂ over N₂ (15.7), which attributed to its high V_n and nitrogen content. Furthermore, optimal sample OAC-500-2.5 owned medium Q_st (21-26 kJ/mol), which was beneficial practical application. This work may inspire new sparks on novel nitrogen-doped adsorbent with inexpensive precursor, low activation temperature and simple preparative tactic, indicating that the nitrogen-doped sample is promising in the practical situation of CO₂ adsorption.