生物质热转换制氢的研究进展

氢气是一种理想的洁净能源。从能源角度和环境角度考虑,发展生物质制氢技术都具有重要的意义。生物质制氢技术主要包括热化学法和生物法,其中热化学法主要是将生物质气化或液化,再进行重整和水蒸气变换反应,获得氢气。本文综述了生物质热化学转化(包括气化、超临界水气化、热裂解等)制氢技术的研究进展,并对典型的制氢技术作了评述和展望。     

结构参数和操作参数对生物质气化制氢技术的影响

生物质气化制氢技术不仅是一种清洁能源技术,而且有助于缓解我国能源压力,优化能源结构。介绍并对比了生物质制氢的主要方法,包括生物法和热化学法制氢技术。热化学法制氢技术的工业化发展较受关注,主要包括气化法、热解法和超临界转化法,其中气化法因产氢量高、废弃物少和工艺要求较易实现等优点,成为目前热化学法制氢的主要方法。阐述了生物质气化过程的基本原理,分别从结构参数(物料特性、气化剂、气化炉种类、催化剂)和操作参数(反应温度、当量比、水蒸气配气比)系统地分析了影响生物质气化过程的主要影响因素及其变化规律,指出应从优化结构参数和操作参数上促进生物质气化制氢技术的发展。     

生物质制氢技术研究进展

对生物质的裂解和气化制氢技术进行了归纳总结,单纯使用生物质裂解或气化制取氢气效果并不理想,使用催化剂裂解气化能够明显提高产气率和产氢率,为以后大规模生物质制氢提供了理论依据。最后简单介绍了本课题组的生物质一体化制氢技术。     

生物质气化制富氢合成气的研究进展

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。     

生物质空气-水蒸气催化气化制氢技术

生物质气化技术已在国内外得到广泛的开发和运用,但由于燃气品质较差,焦油较多,限制了生物质气化气的进一步利用。利用生物质制氢可以实现二氧化碳归零排放,从根本上解决化石能源消耗带来的温室效应问题,已引起世界各国研究者的普遍兴趣。本文介绍了生物质催化气化制氢概况,讨论了在气化过程中发生的主要化学反应以及影响可燃气中氢气含量的主要因素,进而给出了生物质催化气化制氢的典型流程。     

制氢技术的生命周期评价研究进展

氢气既是理想高效的清洁能源,又是用途广泛的化工原料。以传统能源制氢为主导的制氢产业具有高能耗高污染的弊端,在资源环保问题日益突出的当下,全方位对比研究各类制氢技术的优劣特征,为制氢产业提供健康发展的技术路线显得尤为重要。本文主要以传统制氢技术(煤气化制氢、天然气制氢等)和新型制氢技术(热化学制氢、可再生能源发电制氢、生物质气化制氢等)为对象,对其生命周期评价方面的研究进展进行综述。论文首先介绍了生命周期评价的研究过程和思路,阐述了各类制氢技术的基本原理和应用现状,重点研究了各类制氢技术的能耗和温室气体释放数据,同时结合生命周期成本分析,归纳了各制氢技术的制氢成本。论文通过分析各类制氢技术的优劣性,总结得出新型制氢技术具有优秀的节能环保性,但制氢成本较高。其中,风电制氢技术的环保性最佳,而核能热化学制氢在未来具有大规模应用的潜力。根据当前制氢格局的发展状况和各类制氢技术的特点,论文最后作出了关于制氢技术发展的前景展望。     

超临界水条件下生物质气化制氢

生物质制氢是农业废弃物资源化利用的一项很有发展前途的技术。介绍了超临界水条件下生物质的气化制氢技术,论述了温度、压力、停留时间以及反应器对气化产物组成及气化制氢效果的影响,着重阐述了催化剂的影响。分析了目前超临界水气化制氢在有机废弃物资源化应用中存在的主要问题,并展望了超临界水气化制氢的研究前景。     

热化学制氢与生物制氢的工艺技术比较

从制氢机理、工艺流程以及存在问题和发展前景等方面介绍了目前生物质制氢最为主要的两种方法——热化学制氢法和微生物转化制氢法。在对比了解了几种制氢方法后,发现生物质制氢技术最为高效环保,既能优化我国的燃料结构、改善大气污染状况,同时又能减少目前出现的不合理利用方式所带来的二次污染。     

生物质气化技术应用现状及发展前景

生物质能的开发利用可缓解能源紧缺问题、环境污染问题和"三农"问题等国家重大战略问题,而生物质气化是生物质能高品位利用发展最迅速最实用的技术之一。生物质气化技术的研究和开发得到了国内外广泛重视,并取得了较大的进展。本文在分析总结生物质气化技术国内外应用现状的基础上,从生物质气化集中供气技术、热电联产技术、合成液体燃料技术和制氢技术等方面指出了今后生物质气化技术发展面临的机遇和挑战。     

双流化床生物质气化炉研究进展

生物质是重要的清洁可再生能源,双流化床生物质气化技术是将低品位的生物质能转化成高品位氢能的重要途径。本文阐明了双流化床气化过程的基本原理,从燃气中氢气浓度、焦油含量和装置热效率等角度,介绍了双流化床生物质气化技术的早期探索和发展现状,对目前几种典型双流化床生物质气化炉的炉型设计及相关试验研究进行了分析和总结。指出内循环双流化床气化炉结构虽然简单紧凑,但是难以避免气化室和燃烧室之间的气体串混问题;而外循环流化床通过外置返料器很好地解决了气体串混问题。分析了不同气化室优化设计方案对提升燃气品质的理论依据及其优缺点。最后对双流化床生物质气化技术的发展进行了总结和展望,指出双流化床生物质气化制氢具有非常广阔的工业化应用和发展前景。     

Hydrogen from biomass-production by steam reforming of biomass pyrolysis oil

Thermo-conversion of biomass is one of the leading near-term options for renewable production of hydrogen and has the potential to provide a significant fraction of transportation fuel required in the future. We propose a two-step process that starts with fast pyrolysis of biomass, which generates high yields of a liquid product, bio-oil, followed by catalytic steam reforming of bio-oil to produce hydrogen. A major advantage of such a concept results from the fact that bio-oil is much easier and less expensive to transport than either biomass or hydrogen. Therefore, the processing of biomass and the production of hydrogen can be performed at separate locations, optimized with respect to feedstock supply and to hydrogen distribution infrastructure. This approach makes the process very well suited for both centralized and distributed hydrogen production. This work demonstrates reforming of bio-oil in a bench-scale fluidized bed system and provides hydrogen yields obtained using several commercial and custom-made catalysts.     

加快生物质废弃物吸附增强制可再生氢气

作为全球性的优质能源载体,氢的主要生产方式包括碳氢化合物（例如天然气、煤炭和生物质）的热化学过程以及使用电力来源与可再生能源（如风能或太阳能等）的水电解过程。目前的水电解技术在大规模制氢方面经济竞争力亟待提升。本文指出：为了在2060年实现碳中和,迫切需要开发绿氢制备新技术,大力发展可再生制氢和低碳制氢。具有碳捕集、利用和封存的碳氢化合物低碳制氢（蓝色）技术将占重要地位,随后逐步转向可再生制氢（绿色）,并有望全面实现零碳制氢,进而对长期低碳化社会的发展至关重要。文章提出我国生物质资源非常丰富,但生物质废弃物制氢的技术成熟度仍然较低,迫切需要开发从生物质中高效生产可再生氢气的新技术,以显著提高氢气产量并降低成本;吸附增强反应代表了一种可用于可持续生产氢的有前景的新技术;氢气的产率和纯度可以通过过程强化得到显著提高,制氢过程的强化可以在多功能反应器中实现,其中重整和/或气化、水煤气变换和CO₂移除步骤可将重整/水煤气变换反应催化剂和CO₂捕集剂混合而集成到一个反应器中。最后指出：由于该过程潜力巨大,因此应助推耦合气化和吸附增强反应过程从生物质废弃物中生产可再生氢气的工艺过程,以加快推进碳中和进程。     

Sorption enhanced steam reforming (SESR): a direct route towards efficient hydrogen production from biomass‐derived compounds

OVERVIEW: Efficient conversion of biomass to hydrogen is imperative in order to realize sustainable hydrogen production. Sorption enhanced steam reforming (SESR) is an emerging technology to produce high purity hydrogen directly from biomass‐derived oxygenates, by integrating steam reforming, water‐gas shift and CO₂ separation in one‐stage. Factors such as simplicity of the hydrogen production process, flexibility in feedstock, high hydrogen yield and low cost, make the SESR process attractive for biomass conversion to fuels. IMPACT: Recent work has demonstrated that SESR of biomass‐derived oxygenates has greater potential than conventional steam reforming for hydrogen production. The flexibility of SESR processes resides in the diversity of feedstocks, which can be gases (e.g. biogas, syngas from biomass gasification), liquids (e.g. bioethanol, glycerol, sugars or liquid wastes from biomass processing) and solids (e.g. lignocellulosic biomass). SESR can be developed to realize a simple biomass conversion process but with high energy efficiency. APPLICATIONS: Hydrogen production by SESR of biomass‐derived compounds can be integrated into existing oil refineries and bio‐refineries for hydrotreating processing, making the production of gasoline and diesel greener. Moreover, hydrogen from SESR can be directly fed to fuel cells for power generation. Copyright © 2012 Society of Chemical Industry     

The technical feasibility of biomass gasification for hydrogen production

Biomass gasification for energy or hydrogen production is a field in continuous evolution, due to the fact that biomass is a renewable and CO₂ neutral source. The ability to produce biomass-derived vehicle fuel on a large scale will help to reduce greenhouse gas and pollution, increase the security of European energy supplies, and enhance the use of renewable energy. The Värnamo Biomass Gassification Centre in Sweden is a unique plant and an important site for the development of innovative technologies for biomass transformation. At the moment, the Värnamo plant is the heart of the CHRISGAS European project, that aims to convert the produced gas for further upgrading to liquid fuels as dimethyl ether (DME), methanol or Fischer–Tropsch (F–T) derived diesel. The present work is an attempt to highlight the conditions for the reforming unit and the problems related to working with streams having high contents of sulphur and alkali metals.     

An overview of hydrogen production from biomass

Hydrogen production plays a very important role in the development of hydrogen economy. One of the promising hydrogen production approaches is conversion from biomass, which is abundant, clean and renewable. Alternative thermochemical (pyrolysis and gasification) and biological (biophotolysis, water–gas shift reaction and fermentation) processes can be practically applied to produce hydrogen. This paper gives an overview of these technologies for hydrogen production from biomass. The future development will also be addressed.     

生物质水蒸气气化制取富氢合成气及其应用的研究进展

生物质水蒸气气化是有效的热化学转化手段,可将原材料转化为富氢合成气,气体应用更加广泛,有替代化石能源制氢的潜在价值。不同的生物质资源气化和产氢能力存在差异,物料的选择对气化制取富氢合成气至关重要,而调整气化操作参数包括反应温度、水蒸气加入量、催化剂和吸收剂等可进一步优化合成气质量,提升氢气含量。本文首先综述了不同操作条件对生物质水蒸气气化制取富氢合成气的影响。其次,介绍了生物质炭气化制取富氢合成气的研究现状,炭气化可制得高品质的富氢合成气,但过程受动力学限制,需要加入催化剂以提升炭气化速率。文中还简述了以钾盐为催化剂时的催化机理,并展望了富氢合成气的应用,包括制备高纯氢应用于燃料电池和制备合成天然气。     

Bench- and Pilot-Scale Studies of Reaction and Regeneration of Ni–Mg–K/Al2O3 for Catalytic Conditioning of Biomass-Derived Syngas

The National Renewable Energy Laboratory (NREL) is collaborating with both industrial and academic partners to develop technologies to help enable commercialization of biofuels produced from lignocellulosic biomass feedstocks. The focus of this paper is to report how various operating processes, utilized in-house and by collaborators, influence the catalytic activity during conditioning of biomass-derived syngas. Efficient cleaning and conditioning of biomass-derived syngas for use in fuel synthesis continues to be a significant technical barrier to commercialization. Multifunctional, fluidizable catalysts are being developed to reform undesired tars and light hydrocarbons, especially methane, to additional syngas, which can improve utilization of biomass carbon. This approach also eliminates both the need for downstream methane reforming and the production of an aqueous waste stream from tar scrubbing. This work was conducted with NiMgK/Al₂O₃ catalysts. These catalysts were assessed for methane reforming performance in (i) fixed-bed, bench-scale tests with model syngas simulating that produced by oak gasification, and in pilot-scale, (ii) fluidized tests with actual oak-derived syngas, and (iii) recirculating/regenerating tests using model syngas. Bench-scale tests showed that the catalyst could be completely regenerated over several reforming reaction cycles. Pilot-scale tests using raw syngas showed that the catalyst lost activity from cycle to cycle when it was regenerated, though it was shown that bench-scale regeneration by steam oxidation and H₂ reduction did not cause this deactivation. Characterization by TPR indicates that the loss of a low temperature nickel oxide reduction feature is related to the catalyst deactivation, which is ascribed to nickel being incorporated into a spinel nickel aluminate that is not reduced with the given activation protocol. Results for 100?h time-on-stream using a recirculating/regenerating reactor suggest that this type of process could be employed to keep a high level of steady-state reforming activity, without permanent deactivation of the catalyst. Additionally, the differences in catalyst performance using a simulated and real, biomass-derived syngas stream indicate that there are components present in the real stream that are not adequately modeled in the syngas stream. Heavy tars and polycyclic aromatics are known to be present in real syngas, and the use of benzene and naphthalene as surrogates may be insufficient. In addition, some inorganics found in biomass, which become concentrated in the ash following biomass gasification, may be transported to the reforming reactor where they can interact with catalysts. Therefore, in order to gain more representative results for how a catalyst would perform on an industrially-relevant scale, with real contaminants, appropriate small-scale biomass solids feeders or slip-streams of real process gas should be employed.     

生物质热化学制氢的研究进展

介绍了生物质制氢的路线,详细分析了制氢研究的热点-生物质热化学方法,包括热裂解、气化及超临界水气化三种方法的研究进展,总结了相关试验方法及装置,其中介绍了催化剂的使用、实验装置的选取及操作条件的采用,指出了研究中存在的问题,最后对生物质制氢技术进行了展望。     

生物质下吸式气化炉气化制备富氢燃气实验研究

以制取富氢燃气为目标,在自热式下吸式气化炉反应器内,进行了生物质下吸式气化炉富氧/水蒸气及空气气化的制氢特性研究。实验结果表明,与空气气化相比,富氧/水蒸气气化可显著提高氢产率和产气热值。在实验条件范围内,最大氢产率达到45.16 g/kg;最大低位热值达到11.11 MJ/m3。在富氧/水蒸气气化条件下,燃气中H2+CO体积分数达到63.27%—72.56%,高于空气气化条件下的52.19%—63.31%。富氧/水蒸气气化条件下的H2/CO体积比比值为0.70—0.90,低于空气气化条件下的1.06—1.27。实验结果证实:生物质下吸式气化炉富氧/水蒸气气化是一种有效的制取可再生氢源的工艺路线。