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961.
本文研究了生物质还原焙烧赤铁矿的工艺条件以及该过程中赤铁矿对生物质热解产物的影响。确定了还原焙烧的适宜条件为焙烧温度750℃,生物质用量15%,磨矿细度-0.074mm占85%,磁选后可得到品位为61.7%、回收率为87.14%的铁精矿,相比煤基还原低约300℃。赤铁矿对CO2、CO、H2的产出分别在530℃、840℃和500℃后有促进作用,对CH4的产出抑制作用较小,对残碳和焦油的产率也有抑制作用。生物质还原焙烧赤铁矿具有可行性,并且赤铁矿对生物质热解产物有一定影响。 相似文献
962.
In this study, to prepare a series of activated carbon-supported metals for the catalytic reduction of NOx to N2 in excess O2, activated carbons derived from lignocellulosic and herbaceous biomasses were selected as the reducing agents, and alkali and transition metals were used as the catalytic active phases. The effects of the type of biomass, carbonization temperature and catalyst composition on NOx reduction efficiency were analyzed in a fixed-bed flow reactor. The results showed that two temperature regimes are present for the NOx-carbon reaction:at temperatures below 250℃, the NOx adsorption process on the carbon surface was predominant, whereas true NOx reduction by carbon occurred at temperatures above 250℃, producing N2, CO2 and CO. The influence of the carbonization temperature on carbon reactivity depended on the effect of the carbonization temperature on the carbon surface area and the reduction of the metal species on carbon. All studied metals catalyzed both NOx and O2 reduction by carbon, and potassium could strongly enhance the C-NOx reaction without substantial carbon consumption by O2. Moreover, the potassium supported by sawdust-derived activated carbon exhibited higher selectivity and capacity towards NOx reduction than did its previously reported coal-derived counterparts. These properties were ascribed to the high dispersion of the active potassium species on the carbon surface, as observed through the comparison of X-ray photoelectron spectroscopy and powder X-ray diffraction results for the carbons made from biomass and coal-based precursors. 相似文献
963.
The development of a benign environmental catalyst for the generation of biodiesel is an area of importance to reduce the overall usage of fossil fuels. In the current work, biochar was produced by slow pyrolysis of Irul wood sawdust. The optimization for biochar generation was carried out for different reaction temperatures and heating durations. The biochar was used to prepare solid acid catalysts by sulfonation process. The characterization of biochar and the sulfonated catalyst were carried out using Elemental analysis, Fourier Transform Infrared spectroscopy (FTIR), Powder X-ray Diffraction (XRD), Thermo Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Surface area analyzer (BET). The characterization results showed that sulfonation of biochar resulted in biochar based solid acid catalyst containing various functional acidic groups like weak acidic OH groups, strong acidic COOH and SO3H groups. The total acid density and sulfonic acid group density of catalyst were estimated and showed excellent acidic sites concentration which gives a good catalytic activity for biodiesel production through simultaneous esterification and transesterification. The enhanced catalytic activity is due to the high acid density of SO3H groups and the reactant accessibility towards acidic sites as well as the strong affinity between the hydrophilic reactants and the neutral OH groups which are bonded with the polycyclic aromatic carbon rings. The performance of biochar catalyst for the production of biodiesel was evaluated by comparing the yield obtained. The FTIR and Gas Chromatography–Mass Spectroscopy (GC–MS) were also carried out for the analysis of biodiesel produced. 相似文献
964.
965.
作为重要的可再生能源,枝桠类林业废弃物的高效直燃发电是简便可行的生物质资源再利用方式,然而,目前尚未有适合林区工作的移动式枝桠切碎机。针对这一问题,论文提出了一种适用于林间枝桠实地切削的新型移动式枝桠切碎机。进行了切碎机的整体结构设计,基于TRIZ理论进行了自抬式抓送料装置的创新设计,进行了\"渐开线\"螺旋式刀辊机构设计,并对平衡臂连杆等关键部件进行了有限元分析。在此基础上,制作样机并进行了性能测试。新型枝桠切碎机外形尺寸1.5×1.2×1.0 m3,重量仅350 kg,处理能力2.7m3/h,适合南方山区就地处理枝桠,可节省运输费用。 相似文献
966.
Dewi Selvia Fardhyanti Bayu Triwibowo Heri Istanto Muhammad Khusni Anajib Amalia Larasati Windy Oktaviani 《中国化学工程学报》2019,27(2):391-399
Utilization of biomass as a new and renewable energy source is being actively conducted by various parties. One of the technologies for utilizing or converting biomass as an energy source is pyrolysis, to convert biomass into a more valuable product which is bio-oil. Bio-oil is a condensed liquid from the vapor phase of biomass pyrolysis such as coconut shells and coffee shells. Biomass composition consisting of hemicellulose, cellulose, and lignin will oxidize to phenol which is the main content in bio-oil. The total phenolic compounds contained in bio-oil are 47.03% (coconut shell) and 45% (coffee shell). The content of phenol compounds in corrosive bio-oils still quite high, the use of this bio-oil directly will cause various difficulties in the combustion system due to high viscosity, low calorific value, corrosivity, and instability. Phenol compounds have some benefits as one of the compounds for floor cleaners and disinfectants which are contained in bio-oil.The correlation between experimental data and calculations shows that the UNIQUAC Functional-group Activity Coefficients (UNIFAC) equilibrium model can be used to predict the liquid–liquid equilibrium in the phenol extraction process of the coconut shell pyrolysis bio-oil. While the Non-Random Two Liquid (NRTL) equilibrium model can be used to predict liquid–liquid equilibrium in the extraction process of phenol from bio-oil pyrolysis of coffee shells. 相似文献
967.
用微波可高效对生物质烘焙预处理,考察了不同微波烘焙过程对玉米秸秆主要组分的降解作用及酸、碱、甘油催化剂对纤维素转化效率的影响,并对预处理的玉米秸秆进行酶解实验。结果表明,单纯的微波预处理对玉米秸秆中主要组分纤维素、半纤维素和木质素均有强烈的转化作用。无催化剂微波烘焙后,样品中纤维素含量降低了30%。在微波烘焙中添加酸、碱、甘油催化剂,可选择性降解玉米秸秆中的半纤维素或木质素,有效提高预处理后玉米秸秆中的纤维素含量,添加NaOH后纤维素含量增加最明显,由33%增至42%,纤维素最高转化率达65%。 相似文献
968.
《中国化学工程学报》2024,78(2)
Molten salt gasification is a promising technology for biomass conversion due to its advantages of superior heat transfer and the ability of utilizing solar energy to reduce carbon emission. In this study, the characteristics of corncob CO2-gasification in molten salt environments is thoroughly investigated, and the approach of introducing Fe2O3 as catalyst to enhance the syngas yield is proposed. The results showed that the molten salts significantly promoted the conversion of corncob into gaseous products with very low tar and char yield. Compared to O2 and H2O atmospheres, utilizing CO2 as gasifying agent enhanced the yield of gaseous products during the corncob gasification, especially the yields of CO and H2. The introduction of Fe2O3 as a catalyst could further increase the yield of gaseous products and the cold gas efficiency (CGE), and the yield of syngas was increased into 2258.3 ml·g-1 with a high CGE of 105.8% in 900 ℃. The findings evidenced that CO2 gasification in the molten salt environment with Fe2O3 addition can promote the cracking of tar, increasing the syngas yield significantly. Moreover, the energy required to drive the gasification process was calculated, and the total energy consumption was calculated as 16.83 GJ·t-1. The study opened up a new solution for the biomass gasification, exhibiting a great potential in distributed energy or chemical systems. 相似文献
969.
Chemical looping gasification (CLG) is a promising technology for high-quality syngas production.One key issue to successful CLG is the selection of high-performance oxygen carrier.In this study,several Ca-and Mg-rich steelmaking wastes from steel industry,such as blast furnace slag (BF slag),blast furnace dust (BF dust) and Linz-Donawitz converter slag (LD slag),were used as oxygen carriers in chemical loop-ing gasification of biomass.The results showed that the reducibility of Ca-and Mg-rich waste,especially LD slag and BF dust,was superior to that of hematite.Considering long-term operation,the cyclic stability of steelmaking waste was tested.BF dust showed a poor stability,while the other carrier (hematite,BF slag or LD slag) presented an excellent stability during multiple redox cycles in spite of partial sintering and agglomeration.Moreover,the effects of supply oxygen coefficient (O/B ratio) and reaction tempera-ture on CLG of biomass were investigated.The results revealed that Ca-and Mg-rich waste exhibited a higher syngas production compared to hematite.The higher performance could be attributed to the improved reduction rate of Fe2O3 and gasification rate of biomass by Ca or Mg in steelmaking waste.In addition,LD slag exhibited the higher gas value at the O/B ratio of 1 at 900 ℃.As a consequence,LD slag was an appropriate oxygen carrier for CLG of biomass in terms of perfect reducibility,superior cyclic stability and high reactivity. 相似文献
970.