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1.
建立生物质鼓泡流化床气化过程的动力学三维数理模型,气相采用k-ε湍流模型,固相采用基于颗粒动理学理论封闭模型,并自编化学反应子模型。研究了气化炉内固相体积分数、各相的速度以及气化产物的组分的分布,并预测了水蒸气与生物质质量比(S/B)对气化的影响。在鼓泡床的下段固相和气相的速度均呈现振荡变化,特别是在床高H=0.18 m处,由于物料的加入,两相速度在此附近有较大的振荡。在接近鼓泡床床层表面,固相的速度达到了最大。随S/B的增加CO、H_2的摩尔分数增加,CO_2、CH4的摩尔分数减少,在S/B=3.4时,各气体的摩尔分数趋于稳定。  相似文献   

2.
本文提出一种基于太阳能驱动生物质气化的新型发电系统,利用塔式定日镜场聚光产生1000~1500 K高温太阳热能驱动生物质进行气化反应,并集成先进燃气-蒸汽联合循环发电系统高效利用气化合成气。对该系统进行了热力学性能分析,结果表明:与常规生物质气化方式相比,通过驱动生物质发生气化反应,不仅将间歇性的太阳能转化为稳定的合成气化学能,并增加了气化合成气的化学能,同时合成气中的H_2和CO的摩尔含量之比在气化温度为1000~1500 K时达到1.65~2.44,有利于直接合成甲醇等清洁液体燃料。在设计工况下,系统的太阳能热功转化效率将达到23.68%,随着气化反应温度的升高,系统的太阳能份额和输出的电功率增大,系统的总热效率和总效率均下降。研究成果将为高效利用我国西部丰富的太阳能与生物质能提供一条有效途径。  相似文献   

3.
本文根据生物质能源具有的自身特点,提出一个适合生物质能源利用的新型多联产系统.在原有天然气基甲醇生产系统中增加生物质气化子系统,充分利用天然气-水蒸气重整与生物质气化制取合成气中碳氢有效成分互补的特点,通过合理配气满足最佳的甲醇合成要求,因此屏蔽掉了变换,补碳,脱碳等分产必需的工艺过程,同时借助动力系统实现未反应气的合理利用,在满足较高的甲醇产率前提下降低了化工产品能耗,动力系统借助化工过程克服燃料燃烧过程品位损失过大的难题,是组分对口分级转化能量梯级利用的本质体现.针对不同天然气生物质输入比情况下合成气一次性通过,以及最佳输入比情况下未反应气适度循环两种方案,本文分别进行了深入分析,具有8%~14%的节能潜力.为生物质能的高效应用以及缓解能源危机提供了一条有效的途径.  相似文献   

4.
煤粉加压气流床气化特性实验研究   总被引:4,自引:0,他引:4  
煤气化技术由于具有高煤炭利用率和低污染排放,近年米得到快速发展.我国煤种灰熔点普遍偏高,约占保有储量的57%,无法满足现有液态排渣气流床气化技术的需要.为扩大该技术对我国高灰熔点煤种的适应性,本文在25kg/h规模的加压气流床气化装置上,对我国高灰熔点煤种进行了气化特性实验研究.研究结果表明:高温有利干气化反应向吸热方向进行,碳转化率升高,但过多氧气存在,使得气化炉内燃烧份额增加,导致合成气中 CO2和H2O的含量升高,CO、H2含量降低,冷煤气效率下降,因此,存在最佳气化温度.本实验条件下,最伟气化温度为1300~1350℃;1350℃连续运行1小时30分,此时气化炉底部和旋风分离器内的灰渣,整体上仍以固态形式存在,只有灰中部分低熔融成分发生熔融,其熔融部分在数μm左右.  相似文献   

5.
本文利用Barracuda软件对水平内循环流化床气化(HiFBG)特性进行了数值模拟研究。HiFBG技术在保证产气量的同时,降低了系统的高度,延长了固体颗粒在气化系统内的停留时间,提高气化效率和气化气的热值。从模拟结果可以发现,采取HiFBG技术后,合成气管道中CO、H_2的含量较烟气管道出口处高,而N_2的含量比烟气管道中低,因此,本技术可以有效减少合成气中N_2含量,从而提高气化气热值。  相似文献   

6.
对用流化床生物质气化器合成富氢气体,建立了基于非预混燃烧的模型对气化器中的生物质在空气-水蒸汽环境中的气化反应过程的模型,并采用流体力学软件 FLUENT 6.0对过程进行了模拟.通过模拟结果与实验结果的对比分析发现,水蒸汽与生物质的比、空氧比和生物质颗粒的粒径大小是决定产气中氢气含量的重要参数.同时,对气化器中氢气的分布进行了研究.  相似文献   

7.
等离子体催化耦合重整生物质燃气研究   总被引:1,自引:0,他引:1  
采用分步浸溃法制备了Ni-Mg整体式催化剂,加入萘作为焦油模型化合物考察了低温等离子体耦合催化重整生物质粗燃气的性能,研究了放电条件及反应温度对催化重整制备合成气的调变作用.结果表明:高压高频放电产生等离子体耦合催化重整,对重整净化生物质粗燃气有明显效果.在重整温度为750℃,放电频率为22 kHz时CH4的转化率可由催化重整时的86%提高到94%左右,放电条件下可以将合成气的H2/CO比由1.06提高至1.15.温度对耦合重整影响较为显著,CH4、CO2的转化率均随温度的升高而升高,最高可分别达到94%和89%.加入脉冲电晕后生物质粗燃气中的焦油等复杂有机化合物的转化率达到99%以上.  相似文献   

8.
针对传统煤制天然气过程存在的能量利用不合理、碳捕集能耗过高等技术瓶颈,本文探索了一种能实现CO_2零排放的基于化学链燃烧的生物质煤互补天然气动力联产系统。生物质与煤互补从气化源头调节了合成气中H_2/CO比例,有利于甲烷化反应过程,化学链燃烧实现了零能耗的CO_2捕集。研究结果表明:系统总能效率(η_(en))为57.03,效率(η_(ex))为54.65,系统能源节约率高达18.6,实现了系统CO_2零排放。分析了关键参数如氧气碳比(O/C)、蒸气碳比(S/C)、生物质煤互补比例和未反应气循环倍率对系统热力学性能的影响。  相似文献   

9.
本文提出一个基于生物质气化的甲醇-动力多联产系统.该系统突出特色在于取消了变换过程,取消重整过程,并且适度循环未反应合成气,通过耦合化工与动力过程实现化学能的组分对口、分级转化以及物理能梯级利用原则.通过对系统分析(火用)结果表明,该系统与分产系统(独立甲醇生产系统,生物质气化联合循环)相比,节能高达10个百分点,该系统为生物质未来应用提供一个新的途径.  相似文献   

10.
一种组合了合成气在线调整和甲醇合成的双段床反应器,成功应用于由生物油重整得到的富CO2合成气的高效合成甲醇.在前段催化床反应器内,富含CO2的原始生物质合成气在CuZnAlZr催化剂的催化作用下可以有效地转化为含CO的合成气.经过450 oC的合成气在线调整之后,CO2/CO的比率由6.3大幅降至1.2.经过调整后的生物质基合成气在后段催化床反应器内由工业CuZnAl催化剂催化合成甲醇,当反应条件为260 oC 和5.5 MPa时得到每小时每kg催化剂的最大甲醇  相似文献   

11.
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.  相似文献   

12.
A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.  相似文献   

13.
A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.  相似文献   

14.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

15.
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.  相似文献   

16.
17.
A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.  相似文献   

18.
Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.  相似文献   

19.
20.
Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.  相似文献   

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