共查询到19条相似文献,搜索用时 58 毫秒
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串行流化床生物质气化制取富氢气体模拟研究 总被引:8,自引:1,他引:7
利用串行流化床技术将生物质热解气化和燃烧过程分开,气化反应器和燃烧反应器之间通过灰渣进行热量传递,实现了自供热下生物质气化制氢.利用Aapen Plus软件模拟制氢过程,通过比较单反应器生物质气化的模拟结果和实验结果,验证了模拟研究的可行性.重点研究串行流化床中非催化气化与CaCO3作用下的气化过程,探讨了气化温度、蒸汽与生物质的质量配比(S/B)对制氢的影响,为今后开展生物质气化制氢试验提供了理论参考.结果表明:对应不同气化温度,S/B都存在一个最佳值,且随着温度升高其值减小.当气化温度低于750℃时,添加CaCO3可大幅提高氢产率,气化温度为700℃且在S/B约为0.9时氢产率最大,达43.7 mol·(kg生物质)-1(干燥无灰基),比同温度下非催化气化提高了20.3%.随着气化温度升高,CaCO3促进作用减弱. 相似文献
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生物质在流化床中的气化实验 总被引:3,自引:0,他引:3
笔者在意大利Aquila 大学同该校Rapagna 副教授和伊朗博士生Jand Nader 以中国某木材加工厂的加工剩余物木屑为原料,用小型流化床进行了空气气化实验。反应温度控制在800 ℃,气化效率可达70 % ,气化气热值在6 ~12 MJ/Nm 3 。随着空气供给量的增加,气化气热值降低而产气率增加。 相似文献
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本文针对废弃生物的能量再收进行讨论,并用实验测试数据加以论证。在对有代表性的木屑,砻糠、杂草和城市生活垃圾等生物质进行了流化床的冷态模拟和φ200炉子的热态气化试验,得到了满意的结果。主要结论为:固体生物质废料经适当粉碎干燥后即可以用该化床进行资源回收;气化物料度<200mm(单尺度),水份含量<30%时可制得约5μJ/μ~3的粗煤气;采用流化床气化处理法进行资源回收不仅具有废料处理量大(强度达1.5T/μ~2H_r)而且回收的资源能量品位高是最方便实用的气体燃料。 显然,通过本文的研究结果,可以看到目前普通存在的城市垃圾,废弃生物处理的有效手段——流化床处理法的诱人、广泛和美好的前景。 相似文献
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串行流化床生物质气化制氢试验研究 总被引:2,自引:0,他引:2
基于串行流化床生物质气化技术,以水蒸气为气化剂,在串行流化床试验装置上进行生物质气化制氢的试验研究,考察了气化反应器温度、水蒸气/生物质比率(S/B)对气化气成分、烟气成分和氢产率的影响。结果表明:在燃烧反应器内燃烧烟气不会串混至气化反应器,该气化技术能够稳定连续地从气化反应器获得不含N_2的富氢燃气,氢浓度最高可达71.5%;气化反应器温度是影响制氢过程的重要因素,随着温度的升高,气化气中H_2浓度不断降低,CO浓度显著上升,氢产率有所提高;S/B对气化气成分影响较小,随着S/B的增加,氢产率先升高而后降低,S/B的最优值为1.4。最高氢产率(60.3g H_2/kg biomass)是在气化反应器温度为920℃,S/B为1.4的条件下获得的。 相似文献
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中型流化床中的生物质气化实验研究 总被引:13,自引:0,他引:13
以空气为气化介质,在中型流化床反应器上进行了生物质(木屑)气化实验研究。考察了当量比ER(0.20~0.34)、气化温度(670~820℃)对气化结果的影响,初步探讨加入二次风对气化的影响。在实验研究的条件范围内,煤气热值在5650~6665kJ/m3范围内变化,生物质产气率在1.51~2.26m3/kg之间变化,碳转化率在74.3%~90.8%之间变化,气化效率达到61.8%~78.1%;加入适量二次风可以提高气化效率和碳转化率,减少焦油含量。实验结果表明:此流化床气化炉当气化温度在720~770℃之间,当量比ER在0.24~0.28之间时,气化效果最好,此时煤气热值可达到6400~6600kJ/m3,产气率为1.75~1.95m3/kg,碳转化率为83%~89%,气化效率高达71%以上。 相似文献
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A comprehensive model was developed to simulate gasification of pine sawdust in the presence of both air and steam. The proposed model improved upon the premise of an existing ASPEN PLUS-based biomass gasification model. These enhancements include the addition of a temperature-dependent pyrolysis model, an updated hydrodynamic model, more extensive gasification kinetics and the inclusion of tar formation and reaction kinetics. ASPEN PLUS was similarly used to simulate this process; however, a more extensive FORTRAN subroutine was applied to appropriately model the complexities of a Bubbling Fluidized Bed (“BFB”) gasifier. To confirm validity, the accuracy of the model's predictions was compared with actual experimental results. In addition, the relative accuracy of the comprehensive model was compared to the original base-model to see if any improvement had been made.Results show that the model predicts H2, CO, CO2, and CH4 composition with reasonable accuracy in varying temperature, steam-to-biomass, and equivalence ratio conditions. Mean error between predicted and experimental results is calculated to range from 6.1% to 37.6%. Highest relative accuracy was obtained in CO composition prediction while the results with the least accuracy were for CH4 and CO2 estimation at changing steam-to-biomass ratios and equivalence ratios. When compared to the original model, the comprehensive model predictions of H2 and CO molar fractions are more accurate than those of CO2 and CH4. For CO2 and CH4, the original model predicted with comparable or better accuracy when varying steam-to-biomass ratio and equivalence ratios but the comprehensive model performed better at varying temperatures. 相似文献
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A one-dimensional, steady state, numerical model was developed for a fluidized bed biomass gasifier. The gasifier model consists of a fuel pyrolysis model, an oxidation model, a gasification model and a freeboard model. Given the bed temperature, ambient air flow rate and humidity ratio, fuel moisture content and reactor parameters, the model predicts the fuel feed rate for steady state operation, composition of the producer gas and fuel energy conversion. The gasifier model was validated with experimental results. The effects of major mechanisms (fuel pyrolysis and the chemical and the physical rate processes) were assessed in a sensitivity study of the gasification model. A parametric study was also conducted for the gasifier model. It is concluded that the model can be used for gasifier performance analysis. 相似文献
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This paper presents the thermodynamic assessment of biomass steam gasification via interconnected fluidized beds (IFB) system. The performance examined included the composition, yield and higher heating value (HHV) of dry syngas, and exergy efficiencies of the process. Two exergy efficiencies were calculated for the cases with and without heat recovery, respectively. The effects of steam‐to‐biomass ratio (S/B), gasification temperature, and pressure on the thermodynamic performances were investigated based on a modified modeling of the IFB system. The results showed that at given gasification temperature and pressure, the exergy efficiencies and dry syngas yield reached the maximums when S/B was at the corresponding carbon boundary point (S/BCBP). The HHV of the dry syngas continuously decreased with the increase of S/B. Moreover, the exergy efficiency with heat recovery was averagely a dozen percentage points higher than that without heat recovery. Under atmospheric conditions, lower gasification temperature favored the yield and HHV of dry syngas at various S/B. In addition, it also favored the exergy efficiencies of the process when S/B is approximately larger than 0.75. Under pressurized conditions, higher gasification pressure favored both the yield and HHV of dry syngas, as well as the exergy efficiencies at different S/B. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Yingfang Li Bo Yang Wei Gao Mohammad Reza Farahani 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(5):544-548
Gasification is extensively used in the biomass utilization industries and can be applied to manage the municipal waste wastes in order to transform solid wastes into a clean syngas. In this work, we developed an artificial neural network (ANN) to simulate the influence of two important hydrodynamic factors, namely, heating rate and gasifier length on hydrogen yield and hydrogen efficiency. Results showed that with the increase of gasifier length, hydrogen yield was increased due to a considerable increase in the rate of reactions with increasing the gasifier length. It was also found that the hydrogen yield reached a constant rate probably due to a significant increase in the heat and mass transfer limitations, especially at the end of gasifier. 相似文献