共查询到19条相似文献,搜索用时 78 毫秒
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气液及气液固三相浆态鼓泡塔的气相轴向返混系数 总被引:1,自引:0,他引:1
气液及气液固三相浆态鼓泡塔的气相轴向返混系数宋同贵,赵玉龙,苏晓丽,张碧江(中国科学院山西煤炭化学研究所,煤转化国家重点实验室,太原030001)关键词:气液鼓泡塔,浆态鼓泡塔,气相轴向返混1前言在鼓泡塔反应器的设计、放大及数学模拟中,气相轴向返混系... 相似文献
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气液鼓泡塔内液体速度分布的测定 总被引:1,自引:0,他引:1
鼓泡塔作为一种常见的多相反应器,其中液体速度分布的研究一直是热点。本次实验选用用鼓泡塔高约5.5m,塔径0.5m。利用Pavlov管技术,在不同的操作条件下,我们对于塔不同截面处的液体速度分布进行了测定。实验表明,塔内液速分布呈半抛物线状。在无因次径向位置0.6-0.8左右处,液体速度方向发生改变。而影响转折点位置的主要因素是气相表观速度。 相似文献
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在φ100×5mm的鼓泡塔中,用空气-稀醇溶液和空气-稀酸溶液研究了包括分子中碳原子数和羟基、羧基在内的诸因素对气含率的影响。得到了气含率ε_G关联式,用于单元醇(或酸)、多元醇(或酸)的气含率计算。 相似文献
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运用化学反应工程理论分析影响减粘裂化过程诸因素。在塔径φ300mm塔高2700mm冷模装置中考察了横向筛板数、开孔率、孔径、空塔气速、空塔液速等因素对减粘反应塔液相反混的影响,为工业上流式减粘反应塔的设计提供理论和实验数据。 相似文献
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在直径为50 cm,总高为550 cm的鼓泡塔中,采用脉冲示踪技术考察了流场径向分割对鼓泡塔内液相返混特性的影响.实验中气液两相分别为空气和水,气相流速为3.0~8.6 cm/s,液相流速为0.30~1.00 cm/s.实验结果表明:在考察条件下,随着表观液速的增加,停留时间分布曲线的拖尾情况得到改善,鼓泡塔内液相返混... 相似文献
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M. Chidambaram 《加拿大化工杂志》1989,67(3):503-506
The reported experimental data of Pandit and Joshi (1984) on axial and radial steady-state catalyst concentration in a semibatch bubble column slurry reactor is interpreted by the dispersion model. The elliptic partial differential equation with its associated boundary conditions is solved analytically for catalyst concentration by the method of separation of variables. The proposed model adequately fits the experimental data. 相似文献
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Subrata Kumar Majumder 《Chemical engineering science》2008,63(12):3160-3170
Dispersion coefficient of bubble motion based on velocity distribution theory has been analyzed in up and downward gas-liquid two-phase contactor. The intensity of dispersion of phase depends on motion of the dispersed phase and the characteristics of velocity distribution. In this paper the effects of operating and geometric variables on the dispersion coefficient of bubble motion and the characteristic factor of velocity distribution have been analyzed within the range of column diameter 0.10-2.5 m, superficial liquid velocity, 0.04-0.21 m/s and superficial gas velocity 0.41-3.16 mm/s. From the different developed model of longitudinal dispersion coefficient of liquid, comparison of dispersion coefficient of bubble motion and characteristic feature of velocity distribution in down and upflow two-phase contactor has been reported. Also the functionalities of dispersion coefficient of bubble motion and velocity characteristic factor have been developed with operating variables. The condition for dispersion based on velocity pattern has also been discussed in the present work. The present analysis on the dispersion coefficient of bubble motion and velocity distribution factor associated with the knowledge of the liquid phase dispersion in two-phase contactor can give insight into a further understanding and modeling of multiphase reactor in industrial applications. 相似文献
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Yong Kang Bung T. Min Jong B. Nah Sang D. Kim 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,51(2):235-241
This study investigates the adoption of floating contactors to promote the rate of oxygen transfer from non-uniform air bubbles to liquid in a bubble column with continuous operation. The volumetric oxygen transfer coefficient and axial dispersion coefficient of a liquid phase have been analyzed based on the axial dispersion model. Attention was focused on the effects of the volume fraction of the floating contactors on the volumetric oxygen transfer coefficient, axial dispersion coefficient of a liquid phase, and gas phase hold-up in the bubble column. The results have shown that the volumetric oxygen transfer coefficient and gas phase hold-up can increase by up to 25% and 13%, respectively, while the axial dispersion coefficient of a liquid phase decreases by up to 30% by adding floating contactors in the column. 相似文献
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Jiashu Qian Youqing Wu Sheng Huang Shiyong Wu Haiqi Wang Jinsheng Gao 《加拿大化工杂志》2023,101(4):2317-2329
A novel resistance internal is proposed to optimize the flow field and improve the gas–liquid contact in a co-hydrogenation reactor of coal and vacuum residuum. Local gas holdup, local liquid velocity, and characteristics of the bubble were investigated in a scaled-down laboratory model. The quantitative results showed that the resistance internals could reduce the thickness of the liquid reflux layer by a percentage up to 32% and reduce the difference in the local gas holdup at cross-sections of up to 44%. The Sauter mean diameter of the bubble decreased from 20.30 to 16.00 mm, which aroused the increase in bubble surface area by a percentage of up to 71.9%. The resistance internal promoted the breakup of the bubble with multiple mechanisms and provided diversion to fluid. In this work, improvement at multiple scales was realized, and the technical support for industrial application was provided. 相似文献
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Paul Verlaan Jan-Chris Vos Klaas Van T Riet 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1989,45(3):181-190
Axial dispersion and oxygen transfer were investigated in a bubble column (BC) with a circulation loop. A butterfly valve, situated at the bottom of the loop enabled the above-mentioned physical characteristics in the transition regime between typical airlift-loop-reactor (ALR) flow and BC flow to be studied. The Bodenstein number was found to decrease when the liquid velocity was reduced, implicating a less established plug-flow character. The number of circulations required to achieve complete mixing in the reactor was diminished if the liquid circulation was hampered and appeared to be proportional to the Bodenstein number. The volumetric oxygen-transfer coefficient was estimated by an ideally stirred-tank-reactor (STR) model and a plug-flow model. The STR model yielded reliable results for the whole range of operation while the plug-flow model only appeared to be appropriate for the ALR operation mode. The kLa values obtained were included in a generalized correlation for the transition flow regime and were found to increase gradually when the circulation velocity was reduced. 相似文献
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Vishal H. Bhusare Dinesh V. Kalaga Mukesh K. Dhiman Jyestharaj B. Joshi Shantanu Roy 《加拿大化工杂志》2018,96(9):1957-1971
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在带列管内构件的鼓泡塔内测量了4种不同布气方式下的气含率和液速径向分布,并与无列管内构件的空塔中的分布进行了比较。结果表明:中心布气条件下气含率与液速的径向分布比空塔更为陡峭;环隙及近壁布气时呈现出环隙高、两边低的马鞍形分布;均匀布气时径向分布较空塔更为平坦。空塔内气体分布器的影响是局部性的,充分发展段在塔内占主要部分;而在列管塔中气体分布器的影响是全局性的,气含率与液速的初始分布决定着其全塔分布。在带列管的大型鼓泡塔中难以观察到充分发展段的存在,因此,气体分布器的设计具有比空塔更为重要的意义 相似文献
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Shirish S. Thakre Docca V. Phanikumar Ashok S. Khare Jyeshtharaj B. Joshi 《加拿大化工杂志》1999,77(5):826-837
The flow pattern in a bubble column depends upon the column diameter, height, sparger design, superficial gas velocity and the nature of gas–liquid system. In this paper, the effect of some of these parameters have been simulated using Computational Fluid Dynamics (CFD). The relationship of these parameters with the interphase force terms has been discussed. A complete energy balance has been established. Using this methodology, the flow patterns reported by Hills (1974), Menzel et al. (1990), Yao et al. (1991) and Yu and Kim (1991) have been simulated. Excellent agreement has been shown between the CFD predictions and the experimental observations. The above model has been extended to homogenization of an inert tracer. In order to confirm this model, mixing experiments were carried out in a 200 mm i.d. bubble column. A radioactive tracer technique was used for the measurement of mixing time. Tc-99m (99m Tc), in the form of sodium pertechnate salt, was used as the liquid phase tracer. Good agreement has been shown between the predicted and the experimental values of mixing time. The model was further extended for the estimation of axial dispersion coefficient (DL). Excellent agreement between the simulated and the experimental values of the axial dispersion coefficient confirms the predictive capability of the CFD simulations for the mixing process. 相似文献