共查询到19条相似文献,搜索用时 171 毫秒
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农业生物质秸秆低温热解预处理技术 总被引:1,自引:0,他引:1
农作物秸秆类生物质水分含量高、能量密度低、资源分散,因此储存运输成本高,而且可磨性差不易制粉用于煤粉锅炉或气化炉的混合燃烧与气化。生物质低温预处理技术是一种能够解决上述问题的温和热解方法,它能够显著改善生物质的特性。选取棉花秆和小麦秆在固定床实验台上N2氛围下分别升温至200℃、250℃、300℃热解,加热时间均为30 m in。制得的生物质半焦能量密度显著提高,对比原始的生物质其可磨性得到明显改善,并且具有了疏水性,便于储存运输或制粉用于气流床气化。最后根据实验结果进行预处理技术的可行性分析,推荐预处理条件为250℃、30 m in。 相似文献
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生物质烘焙预处理对气流床气化的影响 总被引:4,自引:0,他引:4
为考查生物质在烘焙预处理过程中的能量产率和颗粒研磨变化规律及对气流床气化总体效率的影响情况,在一套小型烘焙试验台上,对4种不同种类的生物质进行烘焙试验,并对固体产物研磨后进行粒径分析.最后通过小型生物质气流床进行气化试验.结果表明:生物质的能量密度随着烘焙温度的提高而升高,其中,中温烘焙(~250℃)能获得较好的固体和能量产率,减少能量损失;烘焙温度是烘焙过程中最重要的影响因素;烘焙可减少生物质研磨时的电耗,使其易磨;气流床气化试验中,烘焙生物质能够改善煤气成分,提高气化的总体效率.总之,在生物质气流床气化过程中,烘焙预处理能为生物质的粒径减小和随后的大规模利用提供了-个良好的解决途径. 相似文献
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烘焙预处理对高含氮木质废弃物气流床气化特性与含氮污染物分布的影响研究 总被引:1,自引:0,他引:1
在螺旋热解反应器上进行不同温度和停留时间下高含氮木废弃物的烘焙预处理,将烘焙后的固体产物进行气流床气化,考察烘焙对高含氮木质废弃物气流床气化特性与含氮污染物分布的影响,结果表明:烘焙预处理可提高气化产气的H_2/CO值与产气热值,降低碳转化率;烘焙后气流床气化产物含氮污染物浓度与直接气化有明显区别,其中NH_3与HCN的浓度均明显低于未烘焙气化,NH_3浓度由未烘焙时的708mg/m~3降至348mg/m~3,HCN浓度降低了27%。在较高的烘焙温度和较长的烘焙停留时间条件下,NH_3与HCN的浓度有所增大,但仍低于未烘焙气化。 相似文献
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不同预处理温度对棉秆焦炭理化及成型燃烧特性的影响 总被引:1,自引:0,他引:1
选取棉秆为原料,采用水热与烘焙2种预处理方法提高棉秆焦炭的燃料特性。经预处理后,得到不同处理温度下棉秆焦炭,并对其理化特性及其成型燃料燃烧特性进行研究;分析水热炭与烘焙炭成型过程及成型能耗、松弛密度、抗压强度和燃烧性能。结果表明:预处理后的生物质性能明显改善,C含量与高位热值(HHV)均有显著提升,但水热炭与烘焙炭成型能耗均高于原料;与原料相比,水热炭的松弛密度和抗压强度明显提高,而烘焙炭相反;在燃烧性能上,SR180综合燃烧特性指数S(29.41×10-7min2·℃3)高于原料(26.21×10-7min2·℃3),2种预处理方法均可提高棉秆焦炭的热稳定性,且拥有较宽的燃烧范围。 相似文献
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水热处理对生物质成型炭理化性质的影响 总被引:1,自引:0,他引:1
棉秆(CS)及木屑(WS)经高压反应釜水热预处理后压制成型,并于固定床热解炉内进行炭化实验,利用电子万能材料试验机、热重分析仪等分析手段分析水热预处理对生物质成型炭的产率、物理性能(机械强度和表观密度)、热值及燃烧性能的影响。研究表明:随着水热温度的升高,生物质成型炭的产率增加且热值稳定,但燃烧性能变差;经水热预处理制得的生物质成型炭灰分产率均小于18%,固定碳产率均大于60%,满足欧标要求;随着水热温度的升高,生物质成型炭的表观密度及抗压强度均先增加后减小;对比所有实验样品,经230℃水热预处理制得的生物质成型炭(CS/WS-HT230-CB)物理性能及燃烧性能最佳,且均优于商用烧烤炭性能。 相似文献
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基于ASPEN PLUS模拟生物质气流床气化工艺过程 总被引:4,自引:1,他引:4
基于ASPEN PLUS模拟平台,对热解后半焦气化与生物质原料直接气化分别进行了模拟计算,得出如下结论:热解方法作为生物质气流床气化工艺的前处理手段是可行的。热解终温为300℃时对气流床气化是最合适的;O/C摩尔比在0.9~1.1之间比较合适;气化温度和碳转化率随着O/C摩尔比的增加而升高;对于300℃半焦进行气化,空气温度预热到550℃比较合适,气化温度可达到1056℃,煤气热值可达到5958kJ/Nm~3,碳转化率也可达到99.59%。 相似文献
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《International Journal of Hydrogen Energy》2019,44(28):14387-14394
Gasification is currently recognized as a mature technology to convert biomass into useful and versatile product gas for further energy and fuel applications. However, there are some remaining problems relating to the process operation and process efficiency due to inherent properties of biomass feedstock such as high moisture content, low energy density and high oxygen content. Strategies to improve the efficiency of biomass gasification as well as the quality of product gas are thus required. For this purpose, a combined process of torrefaction, gasification, and carbon dioxide capture is developed and simulated in a commercial simulator to investigate the performance of a biomass gasification coupled with a pre-treatment and a post-treatment processes. The results show that the quality of product gas is enhanced when combining gasification with a torrefaction and a CO2 capture processes. The heating value of the product gas and the cold gas efficiency are both increased with additional torrefaction. The CO2 capture process using monoethanolamine offers a CO2 removal efficiency of about 83% and consequently increase the product gas heating value up to 27%. 相似文献
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M.J.C. van der Stelt H. Gerhauser J.H.A. Kiel K.J. Ptasinski 《Biomass & bioenergy》2011,35(9):3748-3762
An overview of the research on biomass upgrading by torrefaction for the production of biofuels is presented. Torrefaction is a thermal conversion method of biomass in the low temperature range of 200–300 °C. Biomass is pre-treated to produce a high quality solid biofuel that can be used for combustion and gasification. In this review the characteristics of torrefaction are described and a short history of torrefaction is given. Torrefaction is based on the removal of oxygen from biomass which aims to produce a fuel with increased energy density by decomposing the reactive hemicellulose fraction. Different reaction conditions (temperature, inert gas, reaction time) and biomass resources lead to various solid, liquid and gaseous products. A short overview of the different mass and energy balances is presented. Finally, the technology options and the most promising torrefaction applications and their economic potential are described. 相似文献
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This paper examines thermochemical biomass conversion plants that produce synthesis gas that can be converted into synthetic fuels. Biomass requires forced drying before torrefaction or gasification to increase the heating value of the feed, an energy consuming step that weighs heavy in the energy balance of the plant. This paper shows that decreasing the humidity of the admitted drying air greatly improves the efficiency of the biomass drying. It is possible to reduce the humidity of the air by passing the air on a water adsorbent solid such as activated alumina. The alumina loaded with water can then be regenerated with waste heat, but more efficiently by using synthesis gas and convert the adsorbed water to hydrogen in the water gas shift section. The energy saved in the improved drying step amounts to 2–8% of the total fuel consumption of the plant, depending on the ambient conditions. 相似文献
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《International Journal of Hydrogen Energy》2022,47(100):42040-42050
Torrefaction is a pretreatment method that converts biomass to a fuel-like substance that can replace coal for sustainable power generation. In this work, a thermodynamic-based process simulation model was developed to simulate the gasification of empty fruit bunch (EFB), with torrefaction as pretreatment, to determine the optimum conditions; equivalence ratio, reactor temperature, torrefaction medium concentration, steam-to-biomass (S/B) ratio and system configuration were studied to determine their influence on hydrogen concentration, higher heating value (HHV), syngas ratio and cold gas efficiency (CGE). The highest hydrogen yield was obtained at an S/B ratio of 1.3 at 800 °C, with a syngas ratio of 2.5 and a CGE of 84%. Concentration of torrefaction medium showed no effect on hydrogen concentration due to the simplicity of the model used, but work is in progress in this direction. Therefore, steam gasification is more suitable than air gasification in hydrogen production. 相似文献
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随着我国社会经济的发展,城市垃圾的产量快速上升。采用等离子体气化熔融技术来处理城市垃圾,能避免传统处理方式带来的二次污染问题,但由于我国城市垃圾含水量高、热值低等原因会造成等离子体炬电耗高的问题。本文结合气化熔融技术、回转式预热器、蓄热式燃烧以及余热回收等多项先进技术,理论上设计了一套日处理垃圾能力在10 ~ 30 t的等离子体气化熔融/垃圾处理系统。系统的减容率在95%以上,在充分利用垃圾中的能源的同时,将二噁英的排放控制在国家标准0.1 ng-TEQ/Nm3以内,减少重金属等二次污染物的排放,具有良好的经济性和环保性。 相似文献
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建立下吸式生物质气化炉热力学平衡模型,该模型包括焦炭、焦油和气体,并用已公布的实验数据对模型进行验证,均方根(RMS)在1.304~3.814之间,结果表明该模型的预测值与实验数据吻合较好,可认为模型可靠。然后模拟棉秆在下吸式生物质气化炉中以空气和富氧气体2种气化氛围下,不同操作参数(当量比、预热温度和气化炉反应温度)下对棉秆气化的气体组分、热值和产率的影响。模拟结果表明:富氧气体为气化剂时,当量比从0.20增至0.35时,气体中N2含量比空气显著下降,达10%以上,同时发现能提高气体中H2和CO的含量和热值,热值比空气提高约20%。预热温度对气化成分变化影响有限,随预热温度从30 ℃变化到130 ℃,气体的平均热值从空气的5.2 MJ/m3提高到富氧气体的7.0 MJ/m3。随气化炉内反应温度从750 ℃升至1250 ℃,空气和富氧气体2种气化剂下的H2和CO分别从20.94%、26.84%和21.77%、28.67%下降到4.06%、9.12%和10.49%、21.60%,导致气体的热值降低。 相似文献
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An evaluation on improvement of pulverized biomass property for solid fuel through torrefaction 总被引:1,自引:0,他引:1
The improvement on physical and chemical properties of pulverized biomass from torrefaction is investigated to evaluate the potential of biomass as solid fuel used in boilers and blast furnaces. Three biomasses of bamboo, banyan and willow are considered. The results indicate that when the torrefaction temperature is relatively low such as 230 and 260 °C, the weight loss of biomass depends significantly on the temperature, as a result of consumptions of hemicellulose and cellulose. However, once the torrefaction temperature is as high as 290 °C, the weight losses of various biomass materials tend to become uniform. The decreased O/C ratio in biomass from torrefaction can be explained by intensified lignin content in that the O/C ratio in lignin is low compared to that in hemicellulose and cellulose. Furthermore, the enriched element C in torrefied biomass results in an increase in the calorific value of the torrefied materials. However, the enlarged higher heating value (HHV) of biomass from torrefaction cannot keep up with the weight loss; this leads to the decrease in total energy of biomass as the torrefaction temperature rises. The conducted correlation in predicting the HHV of raw biomass can also be utilized for torrefied biomass. The raw pulverized biomasses are characterized by agglomeration in the regime of smaller particle size. Once the biomasses undergo torrefaction, the dispersion of powder is improved, thereby facilitating the injection of biomass powder. This enhances the applications of pulverized biomass in boilers and blast furnaces. 相似文献
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Jun Zhao Dan Xie Shuzhong Wang Rui Zhang Zhiqiang Wu Haiyu Meng Lin Chen Tao Wang Yang Guo 《International Journal of Hydrogen Energy》2021,46(34):18051-18063
The gasification characteristics of solid waste and wheat straw were investigated in an oxygen-rich atmosphere by using a laboratory-scale continuous fluidized bed reactor in the range of oxidation equivalent (ER) of 0.2~0.5 and reaction temperature of 600 °C~900 °C. Gasification of biomass and waste is an economical method for hydrogen production. When air is used as a carrier gas to gasify municipal solid waste, increasing the oxygen concentration can effectively increase the hydrogen concentration of the syngas. The product distribution of gasification reaction under different mixing ratios and reaction parameters was obtained. As is shown in the results, first, when the ER is between 0.2 and 0.5, if ER decreases by 0.1, the hydrogen concentration of gas production will increase by about 30%; second, if the oxygen concentration increases by 5%, the hydrogen concentration of gas production will increase by about 14%, and the calorific value of gas production will increase by about 14–18%; third, after adding wheat straw in a ratio of 1:1, due to the reduction of plastics, the overall yield of syngas decreased, but the yield of hydrogen increased, and the concentration of hydrogen in syngas increased by 6.4%. 相似文献