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基于多相质点网格方法 (multi-phase particle-in-cell,MP-PIC)对工业尺度的双流化床生物质气化过程进行了三维全循环数值模拟。其中,在拉格朗日框架下求解颗粒团运动,采用大涡模拟法(large-eddy simulation, LES)求解气相湍流,同时考虑复杂的气固耦合以及生物质的热解、气化、均相/异相反应。首先,通过独立性检验确定了计算所需的最佳网格数与计算颗粒数,且模拟结果和实验结果对比良好。其次,揭示了流化床内生物质气化过程中的气固流动特性及气体组分分布规律,研究了床内温度、生物质粒径、曳力模型等因素对产物气体组分分布的影响。结果表明:温度升高,出口处的CO摩尔分数增加,而其余组分都减小;较小生物质粒径的气化效果要优于较大的生物质颗粒粒径;曳力模型对各产物气体组分的摩尔分数几乎无影响。 相似文献
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生物质气化制取富氢合成气因其原料的清洁可再生性、产物应用方式的多样性被认为是最具发展前景的制氢方式之一。催化剂对调控生物质气化产物组成及焦油的裂解具有重要作用。本文综述了化石能源制氢、水分解制氢和生物质制氢方法,分析了生物质气化制氢的优势和局限性,以及存在的问题;重点介绍了生物质气化制氢的影响因素(气化剂、反应温度和催化剂)和用于生物质气化的主要催化剂种类(镍基、白云石和碱及碱土金属催化剂)及其特点,分析国内外生物质气化制取富氢合成气和催化剂的研究现状,探讨了催化气化制取富氢合成气的发展前景,提出有待解决的问题和研究方向。 相似文献
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煤和生物质共气化协同效应的初步研究 总被引:3,自引:0,他引:3
采用等温热重法对神木煤焦、稻草焦、高梁秆焦和松木屑焦以及煤焦和生物质焦的混合物进行了CO2气化研究。结果表明,煤焦和生物质焦反应活性由大到小的顺序为松木屑焦〉高粱秆焦〉稻草焦〉神木煤焦,煤焦和稻草焦及高梁焦共气化存在明显的协同效应;煤焦和松木屑焦的共气化没有观察到协同效应;当煤焦和脱灰后的稻草焦、高梁焦进行共气化时,协同效应消失。在处理量是8kg/h的流化床实验装置上,比较了煤单独气化和煤与三种生物质共气化的气化结果,发现气化过程中,碳转化率的顺序与物料的气化反应性一致,协同效应不明显。 相似文献
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阐述了利用串行流化床制取生物质合成气的技术,该技术将生物质气化过程与燃烧过程分开,气化反应器和燃烧反应器之间通过床料进行热量传递,并通过生物质补燃实现自供热。利用ASPEN PLUS软件建立了串行流化床制取合成气的模型,通过将模拟数值与实验结果相比较,验证了模拟研究的可行性。重点研究了气化温度、水蒸汽与生物质的质量配比(S/B)对制取生物质合成气的影响。结果表明,为获取较高品质的生物质合成气并得到较高的碳转化率、气化份额和合成气产率,气化温度以650~800℃为宜,S/B应在0.2~1.0之间。 相似文献
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生物质能是一种重要的可再生能源。通过Aspen Plus软件平台,建立生物质气化反应器模型,对生物质气化过程进行模拟计算,探讨了不同反应条件,包括气化温度、压力以及水蒸气与生物质质量配比(S/B)对气化产物成分的影响。计算结果表明,采用生物质蒸汽气化技术可获得体积分数为60%以上的富氢燃料气,且增大水蒸气与生物质质量配比有利于氢气产率的提高。 相似文献
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Reaction kinetics and producer gas compositions of steam gasification of coal and biomass blend chars, part 1: Experimental investigation 总被引:1,自引:0,他引:1
Biomass and coal are important solid fuels for generation of hydrogen-rich syngas from steam gasification. In this work, experiments were performed in a bench-scale gasifier to investigate the effect of coal-to-biomass ratio and the reaction kinetics for gasification of chars of biomass, coal and coal–biomass blends. In the gasification of these chars, steam was used as the gasification agent, while nitrogen was used as a gas carrier. The gasification temperature was controlled at 850, 900 and 950 °C. Gas produced was analysed using a micro-GC from which carbon conversion rate was also determined. From the experiments, it is found that the coal and biomass chars have different gasification characteristics and the overall reaction rate decreases with an increase in the ratio of coal–to-biomass.The microstructure of the coal char and biomass char was examined using scanning electronic microscopy (SEM), and it was found that the biomass char is more amorphous, whereas the coal char has larger pore size. The former enhances the intrinsic reaction rate and the latter influences the intra particle mass transportation. The difference in mass transfer of the gasification agent into the char particles between the two fuels is dominant in the char gasification. 相似文献
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基于Fluent软件的生物质气化模拟研究 总被引:1,自引:0,他引:1
基于Fluent软件,建立流化床反应器模型,对生物质-水蒸气气化过程进行模拟,研究温度对生物质气化过程的影响,同时分析碳转化率、气体成分以及气体总产率的变化规律。结果表明:模拟结果与实验数据吻合良好,碳转化率及气体总产率随温度的升高而升高,床层高度对CO、 H2生成具有较大影响。模拟计算条件下,氢气体积分数高达55%,这说明水蒸气作为气化介质有利于气化过程中产生更多的H2。Fluent软件能够很好的对生物质气化过程进行模拟,可以作为生物质气化研究的一个重要工具。 相似文献
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介绍了生物质气化重整的研究发展现状,主要包括催化气化重整和高温介质气化技术。总结了催化气化重整过程中催化剂的研究情况,归纳了催化剂的作用,重点介绍了天然矿石催化剂、镍基催化剂和贵金属催化剂在生物质气化重整中的应用,并分析了生物质气化催化重整方法在工业应用中存在催化剂易失活的生物技术难点。此外,还介绍了当前出现的生物质高温介质气化技术,包括高温空气气化技术和高温水蒸气气化技术,阐明了其研究重点以及未来发展方向。 相似文献
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生物质气化是一种在高温氧化性介质作用下将生物质热分解为可燃性气体的热解技术。为了提高生物质气化过程中气化效率、调整可燃性气体组分的含量和去除焦油,通常需要采用不同气化介质、改变气化条件或添加不同的催化剂。本文重点综述了生物质气化所使用的介质和催化剂种类以及气化条件对气化气组分,主要是H2和CO的影响规律。最后对未来生物质气化研究进行了展望,提出了几个待研究解决的问题。 相似文献
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生物质气化是一种在高温氧化性介质作用下将生物质热分解为可燃性气体的热解技术。为了提高生物质气化过程中气化效率、调整可燃性气体组分的含量和去除焦油,通常需要采用不同气化介质、改变气化条件或添加不同的催化剂。本文重点综述了生物质气化所使用的介质和催化剂种类以及气化条件对气化气组分,主要是H2和CO的影响规律。最后对未来生物质气化研究进行了展望,提出了几个待研究解决的问题。 相似文献
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Investigation of thermochemical conversion of biomass in supercritical water using a batch reactor 总被引:1,自引:0,他引:1
This study focused on gasification of biomass and a biomass model compound. Data are presented that show the presence of supercritical water enhances gasification efficiency, as it participates as both a solvent and a reactant. It is established that biomass gasification efficiencies are in the same range for all types of biomass. The thermodynamic changes of state are functions of elemental composition, not biomass species. The oxidation state of carbon atom of biomass is a key variable in determining the changes in enthalpy during both conventional combustion and supercritical water gasification. The oxidation state of the feed (together with the reaction conditions that influence the degree to which water participates as a reactant) also determines the vapor product composition.Decomposition reactions to vapor products are rapid and complete at high temperature (?550 °C), catalytic mediation is not required. Temperature and residence time are important operating parameters for SCW gasification. Less important are the pressure of gasification (in the range of 40-67 MPa) and the presence of catalyst. The vapor yield, gas composition, the carbon and hydrogen balance of SCW gasification are functions of gasification temperature, residence time and biomass load (concentration). 相似文献
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Air gasification of different biomass fuels, including forestry (pinus pinaster pruning) and agricultural (grapevine and olive tree pruning) wastes as well as industry wastes (sawdust and marc of grape), has been carried out in a circulating flow gasifier in order to evaluate the potential of using these types of biomass in the same equipment, thus providing higher operation flexibility and minimizing the effect of seasonal fuel supply variations. The potential of using biomass as an additional supporting fuel in coal fuelled power plants has also been evaluated through tests involving mixtures of biomass and coal–coke, the coke being a typical waste of oil companies. The effect of the main gasifier operating conditions, such as the relative biomass/air ratio and the reaction temperature, has been analysed to establish the conditions allowing higher gasification efficiency, carbon conversion and/or fuel constituents (CO, H2 and CH4) concentration and production. Results of the work encourage the combined use of the different biomass fuels without significant modifications in the installation, although agricultural wastes (grapevine and olive pruning) could to lead to more efficient gasification processes. These latter wastes appear as interesting fuels to generate a producer gas to be used in internal combustion engines or gas turbines (high gasification efficiency and gas yield), while sawdust could be a very adequate fuel to produce a H2-rich gas (with interest for fuel cells) due to its highest reactivity. The influence of the reaction temperature on the gasification characteristics was not as significant as that of the biomass/air ratio, although the H2 concentration increased with increasing temperature. 相似文献
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Prediction of the behaviors of H2S and HCl during gasification of selected residual biomass fuels by equilibrium calculation 总被引:2,自引:0,他引:2
H2S and HCl released during biomass gasification can decrease the performance of high-temperature fuel cells in an Integrated Biomass Gasification Fuel Cell power-generating system. In this study, the behaviors of such poisonous gases during the gasification of different biomass fuels at various temperatures ranging from 673 to 1473 K were predicted using an equilibrium calculation approach. The predictions showed not only a difference in emission behaviors of HCl and H2S among the biomass fuels, but also a low HCl emission (below 10 ppmv) for a few of the fuels at any temperature. In addition, the influence of biomass metal composition and gasification temperature on emission behavior was investigated by analyzing the distribution of chlorine and sulfur compounds and the phase diagram of selected elements such as silicon and aluminum. Finally, we suggest that the addition of a potassium-rich biomass to a potassium-poor biomass has the potential to reduce the HCl emission during gasification and then to maintain the HCl concentration in gas phase below the tolerance concentration of the fuel cells. 相似文献