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煤炭与生物质共热解是实现煤炭高效清洁利用的重要途径之一。共热解可改善煤炭单独热解产生的污染问题和生物质单独利用时能源密度低、季节性供应不平衡的问题,不仅能提高煤炭转化效率,还能获得更高品质油品。本文从煤与生物质共热解的影响因素、研究方法和共热解过程中组分间相互作用等方面出发,对近期国内外煤与生物质共热解的研究进行综述。总结了生物质种类、热解工艺参数和热解反应器的类型对煤与生物质共热解过程的影响规律以及煤与生物质在共热解过程中的相互作用过程,即半焦与挥发分间的相互作用、挥发分间的相互作用、生物质中碱金属对共热解的催化作用,并针对如何进一步认识煤与生物质相互作用机理、提高共热解效率等问题和发展方向作了展望。 相似文献
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挥发分-半焦交互作用是生物质热化学利用过程普遍存在的现象。为了解析交互反应对生物质热解半焦特性的影响,利用一阶固定床/流化床反应器及快速热裂解仪进行实验。针对挥发分-半焦交互反应,对碱金属和碱土金属(AAEM)元素的析出特性展开了研究,同时分析了交互反应对生物质热解半焦反应活性的影响。结果表明在700~900℃范围内,交互反应的存在使得热解成焦率较无交互反应下有所提高。热解过程中交互反应导致了单价K元素析出量增加,对二价Ca/Mg元素的析出影响较小。挥发分-半焦交互反应的存在使得半焦反应活性对温度的敏感度降低,随温度的升高其反应速率的下降幅度变缓。 相似文献
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生物质能源作为可再生能源的重要组成部分,其综合高效利用在能源替代与补充、保护生态环境等方面具有重要的战略意义。生物油是生物质通过热裂解技术获得的液体产物,具有能量密度较高、环境友好、可再生及可直接输送等优点,可替代传统化石燃料推广使用,解决日益严重的能源紧缺与环境污染等问题。生物质热解制油技术的开发与利用,已成为新世纪可持续能源研究领域的重要课题之一。总结了近年来生物质热解制油技术的主要研究进展,重点关注热解反应器、催化热解技术与生物油的提质利用方面的研究,介绍了碱金属、氧化物和分子筛3种生物质热解催化剂,以及乳化、催化加氢、催化裂解、催化酯化和重整制氢5种生物质提质方法,最后对生物质热解技术的现状及发展趋势进行了总结和概括。 相似文献
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为了解高含K玉米秸秆在不同热解温度下碱金属的析出规律,建立了一维水平管式炉,利用FTIR、SEM-EDX、XRD等测试手段及化学分馏法对碱金属的释放规律及热解半焦中赋存形式进行深入实验研究。结果表明:K是玉米秸秆的主要碱金属元素,且91%的K以无机K的形式存在;300~600℃主要为有机K的分解、释放阶段,大于600℃主要为KCl、K2SO4等无机K分解、释放。K元素由颗粒内部向表面迁移,并在700℃出现表面K盐富集,继续升温富集程度降低;Na和K析出规律相似,Ca和Mg热稳定性强,热解过程多以稳定的化合物形式存在于热解半焦中,不易析出到气相。 相似文献
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Heating value of biomass and biomass pyrolysis products 总被引:3,自引:0,他引:3
Studies conducted on the heating value of various types of biomass components and their pyrolysis products such as char, liquids and gases are presented. Heating values of chars are comparable with those of lignite and coke; heating values of liquids are comparable with those of oxygenated fuels such as methanol and ethanol, which are much lower than those of petroleum fuels. Heating values of gases are comparable with those of producer gas or coal gas and are much lower than that of natural gas. It is also found that the heating values of products are functions of the initial composition of biomass; correlations are developed to express these. Also, correlations are developed which explain the influence of ash elements on heating values of the pyrolysis products and on percentage distribution of energy in the products. 相似文献
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生物质炭吸附及其与O3耦合处理生物质废水 总被引:1,自引:0,他引:1
针对我国生物质废水污染问题,建立生物质炭吸附、生物质炭/O3耦合处理生物质废水的工艺,并与O3氧化工艺比较。生物质炭吸附处理生物质废水的工艺中,研究了生物质炭吸附生物质废水中的有机物的吸附平衡曲线,考察了吸附时间、生物质炭投加量、不同炭种对COD脱除率的影响。生物质炭吸附生物质废水中的有机物的吸附平衡曲线符合Langmuir方程,吸附平衡常数为8.833×10-5 L/mg,饱和吸附容量为1.136×106 mg/g;20℃下,生物质炭的投加量为20g/100mL废水,吸附15min,废水相COD值可从12496mg/L降至761mg/L,有机物脱除率可达93.9%。单独O3降解及先O3降解后生物质炭吸附的两步法工艺不适合生物质废水的处理,生物质炭/O3协同的一锅法处理废水效果最佳,在生物质用量仅为1g/100mL废水,臭氧流速为150mL/min,处理时间20min时,COD脱除率高于90%。 相似文献
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《The Journal of Supercritical Fluids》2009,48(3):391-399
Different hydrothermal biomass gasification processes are under development. In contrast to biomass gasification processes without water, biomass with the natural water content (“green biomass”) can be converted completely and energetically efficiently to gases. Depending on the reaction conditions, methane or hydrogen is the burnable gas produced. Some processes use catalysts. In recent years, significant progress was achieved in the development of various hydrothermal biomass gasification processes. However, some challenges still exist and technical solutions are needed before large-scale production facilities can be built. 相似文献
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The kinetics of the pyrolysis of lignocellulosic materials was studied with a view of providing simple kinetic models for engineering purposes. Experimental data obtained by means of thermal analysis techniques suggest that the pyrolysis of fine particles (below 1 mm) can be considered to be controlled by pyrolysis kinetics. The rate of pyrolysis of one biomass type can be represented by the sum of the corresponding rates of the main biomass components (cellulose, lignin, hemicellulose). The kinetics of each of these components was simulated by a kinetic scheme capable of predicting the pyrolysis rate and the final weight-loss for a wide range of pyrolysis parameters including various heating conditions. 相似文献
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Biomass has in recent years been considered as a raw material for the production of fuels and chemicals. This work discusses
the reasons for the increased interest in mainly lignocellulosic biomass. Gasification, pyrolysis, and depolymerization by
hydrolysis are analyzed as key biomass technology. We also discuss which of the sugars obtained via depolymerization by hydrolysis
can be processed into fuel or key intermediates of the chemical industry. Lignocellulosic biomass contains such extractants
as fatty acids and terpenes, and we therefore describe the catalytic reactions of these substances for the synthesis of fuels
and chemicals. Some typical reactions of biomass processing (oxidation, hydrogenation, cracking, etc.) are conceptually close
to the process widely known in the refining and chemical industries. There are, however, other considerations due to, e.g.,
the large number of functional (hydroxyl and other) groups, and the processing of biomass components therefore requires dehydration,
aldol condensation, ketonization, decarboxylation, etc. We cover the fundamentals of the approaches to selecting catalysts
for these reactions. 相似文献
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