共查询到19条相似文献,搜索用时 140 毫秒
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生物质热解气重整试验平台设计与试验 总被引:1,自引:0,他引:1
针对热解气焦油含量高、热值低的问题,文章基于焦油催化裂解和热解气气化重整原理,提出了生物质热解气重整工艺路线,并设计、搭建了生物质热解气重整试验平台,该试验平台主要由热解、催化重整、产品收集、控制系统等组成。以玉米秸秆为原料,在该试验平台上开展了热解气重整试验,试验结果表明:在以石英砂作为惰性材料的条件(高温裂解)下,热解气产率为33.8%,焦油转化率为64.3%;在玉米秸秆炭催化裂解条件下,热解气产率为37.8%,焦油转化率72.6%;高温裂解和催化裂解条件下生成的热解气的热值均达到了17MJ/m3以上。热解气重整试验平台达到了设计目的,为热解气重整研究提供了理论支持和技术支撑。 相似文献
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生物质快速热裂解工艺及其影响因素 总被引:8,自引:1,他引:8
介绍了目前生物质快速热裂解的工艺及其影响因素,表明了生物质快速热裂解工艺及技术是目前生物质能利用各种方式中很有前途的利用方式。以小型流化床为例着重介绍了生物质快速裂解装置组成及设备工作原理,并分析了影响生物质快速热裂解过程及产物的主要因素,分析表明,温度是影响热裂解过程中最主要因素。 相似文献
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分析生物质油6种模拟物在裂解温度500℃,不同质量空速条件下的催化裂解产物。不含芳环的生物质油模拟物(乙酸、甲醇、环戊酮和糠醛)经过HZSM-5分子筛催化剂催化裂解后的产物中,均含有苯、萘、茚和多环芳烃及其衍生物,而苯酚和间甲酚经过HZSM-5分子筛催化裂解后,产物中主要是酚类化合物。根据模拟物催化裂解产物,推测不同类型化合物的催化裂解反应途径,说明生物质裂解油催化裂解精制反应过程主要发生脱氧和芳烃化反应,为生物质油催化裂解精制机理研究提供了理论依据。 相似文献
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测定生物质裂解油和催化裂解精制油沥青质的平均分子质量和元素含量,计算两种沥青质基本结构单元的平均分子式。通过1H-NMR,13C-NMR波谱计算得到一系列平均结构参数,建立生物质裂解油和催化裂解精制油沥青质的分子模型,并用傅里叶变换红外光谱进行验证。分析结果表明:精制后的催化裂解精制油的沥青质含量减少,分子量降低,含氧官能团明显少于生物质裂解油沥青质,而芳环数目增加。由此可见,经过精制反应后的催化裂解精制油沥青质的分子量变小,氧含量降低,芳香度增加,从而会影响生物质油的品质。 相似文献
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生物质热解是一种重要的热转化技术,同时也是生物质气化、燃烧与液化等热转化过程的初始阶段,因此生物质热解的研究具有很好的理论意义与应用前景。基于这样的背景,选用固定床反应器,以白松、花生壳和稻秸为生物质样品,对其慢速热解的各相产物、产率进行比较,然后对不同生物质的热解气体产物进行分析,最后深入考察碱金属催化剂(K2CO3)对于不同生物质催化裂解过程所产生的影响。结果表明,在相同慢速热解条件下,稻秸的制氢效果最为明显。在加入碱金属催化剂后,发现相较于白松和稻秸,K2CO3对于花生壳的催化制氢效果尤为显著。 相似文献
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Despite remarkable progress in catalytic fast pyrolysis, bio-oil production is far from commercialization because of multi-scale challenges, and major constraints lie with catalysts. This review aims to introduce major constraints of acid catalysts and simultaneously to find out possible solutions for the production of fuel-grade bio-oil in biomass catalytic fast pyrolysis. The catalytic activities of several materials which act as acid catalysts and the impacts of Bronsted and Lewis acid site on the formation of aromatic hydrocarbons are discussed. Considering the complexity of catalytic fast pyrolysis of biomass with acid catalysts, in-depth understandings of cracking, deoxygenation, carbon-carbon coupling, and aromatization for both in-situ and ex-situ configurations are emphasized. The limitation of diffusion along with coke formation, active site poisoning, thermal/hydrothermal deactivation, sintering, and low aromatics in bio-oil are process complexities with solid acid catalysts. The economic viability of large-scale bio-oil production demands progress in catalyst modification or/and developing new catalysts. The potential of different catalyst modification strategies for an adequate amount of acid sites and pore size confinement is discussed. By critically evaluating the challenges and potential of catalyst modification techniques, multi-functional catalysts may be an effective approach for selective conversion of biomass to bio-oil and chemicals through catalytic fast pyrolysis. This review offers a scientific reference for the research and development of catalytic fast pyrolysis of biomass. 相似文献
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Shaomin Liu Jinglin Zhu Mingqiang Chen Wenping Xin Zhonglian Yang Lihong Kong 《International Journal of Hydrogen Energy》2014
This study introduces an innovative process of generating hydrogen-rich gas from biomass through the catalytic pyrolysis of biomass in a two-stage fixed bed reactor system. Water hyacinth was used as the biomass feedstock. The effects of various factors such as pyrolysis temperature, catalytic bed temperature, residence time, catalyst, and the nickel content of the catalyst on the pyrolysis productivity were investigated and the yields of H2, CO, CH4, and CO2 were obtained. Results showed that the high productivity of hydrogen can be obtained particularly by increasing the catalytic bed temperature, residence time, and catalysts. The favorable reaction conditions are as follows: a first-stage pyrolysis temperature of 650 °C–700 °C, a second-stage catalytic bed temperature of 800 °C, a catalytic pyrolysis reaction time of 17 min, and a nickel content of 9% (wt %). 相似文献
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In this study, different char based catalysts were evaluated in order to increase hydrogen production from the steam pyrolysis of olive pomace in two stage fixed bed reactor system. Biomass char, nickel loaded biomass char, coal char and nickel or iron loaded coal chars were used as catalyst. Acid washed biomass char was also tested to investigate the effect of inorganics in char on catalytic activity for hydrogen production. Catalysts were characterized by using Brunauer–Emmet–Teller (BET) method, X-ray diffraction (XRD) analyzer, X-ray fluorescence (XRF) and thermogravimetric analyzer (TGA). The results showed that the steam in absence of catalyst had no influence on hydrogen production. Increase in catalytic bed temperature (from 500 °C to 700 °C) enhanced hydrogen production in presence of Ni-impregnated and non-impregnated biomass char. Inherent inorganic content of char had great effect on hydrogen production. Ni based biomass char exhibited the highest catalytic activity in terms of hydrogen production. Besides, Ni and Fe based coal char had catalytic activity on H2 production. On the other hand, the results showed that biomass char was not thermally stable under steam pyrolysis conditions. Weight loss of catalyst during steam pyrolysis could be attributed to steam gasification of biomass char itself. In contrast, properties of coal char based catalysts after steam pyrolysis process remained nearly unchanged, leading to better thermal stability than biomass char. 相似文献
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《能源学会志》2020,93(1):425-435
A higher amount of oxygenates is the main constraint for higher yield and quality of aromatics in catalytic pyrolysis while a study of hydrocarbon production with a balance of reactive species lies importance in the catalytic upgrading of pyrolytic vapor. Catalytic pyrolysis of pinewood sawdust over acidic (ZSM-5) and basic (CaO) catalyst was conducted by means of Py-GC/MS to evaluate the effect of biomass to catalyst loading ratio on aromatic hydrocarbon production. Catalytic pyrolysis with four different biomass to catalyst ratios (0.25:1, 0.5:1, 1:1, and 2:1) and non-catalytic pyrolysis were conducted. It has been obtained that ZSM-5 showed better catalytic activity in terms of a high fraction of aromatic hydrocarbon. The ZSM-5 catalyst showed a potential on the aromatization as the yield of aromatic hydrocarbon was increased with a higher amount of ZSM-5 catalyst and the highest yield of aromatics (42.19 wt %) was observed for biomass to catalyst ratio of 0.25:1. On the other hand, basic CaO catalyst was not selective to aromatic hydrocarbon from pinewood sawdust but explored high deacidification reaction in pyrolytic vapor compared to ZSM-5 catalyst, whereas non-catalytic pyrolysis resulted in acidic species (13.45 wt %) and phenolics (46.5 wt %). Based on the results, ZSM-5 catalyst can only be suggested for catalytic pyrolysis of pinewood sawdust for aromatic hydrocarbon production. 相似文献
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为了将生物质能高效转化为高品位不含氧的液体燃料,以纤维素为例,研究了以催化热解方式将热解产物转化为芳香烃类液体燃料的过程.实验发现,纤维素热解产生的含氧有机小分子,可以通过催化热解的形式高效转化为不含氧的芳香烃类液体.催化剂采用HZSM-5(23)、催化剂原料质量比例为5∶1、热解温度为650℃、升温速率为10000 K/s的工况为纤维素催化热解的最佳工况,单环芳烃、多环芳烃产率分别为9.90%和12.91%,总芳香烃类产率为22.81%.热解温度提升至650℃前,更高的热解温度能获得更高的芳香烃产率.继续提高热解温度,单环芳烃、多环芳烃分子间还可能进一步发生聚合反应,最终产生积碳.同时本文也提出了一种可行的纤维素催化热解中的反应途径,与本文实验结果较为匹配. 相似文献
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The past decades have seen increasing interest in developing pyrolysis pathways to produce biofuels and bio-based chemicals from lignocellulosic biomass. Pyrolysis is a key stage in other thermochemical conversion processes, such as combustion and gasification. Understanding the reaction mechanisms of biomass pyrolysis will facilitate the process optimization and reactor design of commercial-scale biorefineries. However, the multiscale complexity of the biomass structures and reactions involved in pyrolysis make it challenging to elucidate the mechanism. This article provides a broad review of the state-of-art biomass pyrolysis research. Considering the complexity of the biomass structure, the pyrolysis characteristics of its three major individual components (cellulose, hemicellulose and lignin) are discussed in detail. Recently developed experimental technologies, such as Py-GC–MS/FID, TG-MS/TG-FTIR, in situ spectroscopy, 2D-PCIS, isotopic labeling method, in situ EPR and PIMS have been employed for biomass pyrolysis research, including online monitoring of the evolution of key intermediate products and the qualitative and quantitative measurement of the pyrolysis products. Based on experimental results, many macroscopic kinetic modeling methods with comprehensive mechanism schemes, such as the distributed activation energy model (DAEM), isoconversional method, detailed lumped kinetic model, kinetic Monte Carlo model, have been developed to simulate the mass loss behavior during biomass pyrolysis and to predict the resulting product distribution. Combined with molecular simulations of the elemental reaction routes, an in-depth understanding of the biomass pyrolysis mechanism may be obtained. Aiming to further improve the quality of pyrolysis products, the effects of various catalytic methods and feedstock pretreatment technologies on the pyrolysis behavior are also reviewed. At last, a brief conclusion for the challenge and perspectives of biomass pyrolysis is provided. 相似文献