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多段分级转化流化床颗粒浓度的数值模拟 被引量:3
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作者 王海艳 郝振华 +1 位作者 王志雨 房倚天 《化学反应工程与工艺》 CAS CSCD 北大核心 2013年第1期42-50,共9页
多段分级转化流化床煤气化反应器是由鼓泡射流流化床和快速流化床耦合而成的新型气化炉,采用欧拉双流体模型对其气固两相流动行为进行了数值模拟。模拟结果表明,两种流型的耦合,并非两种流态形式的简单叠加,回料口下段床内轴向浓度呈&qu... 多段分级转化流化床煤气化反应器是由鼓泡射流流化床和快速流化床耦合而成的新型气化炉,采用欧拉双流体模型对其气固两相流动行为进行了数值模拟。模拟结果表明,两种流型的耦合,并非两种流态形式的简单叠加,回料口下段床内轴向浓度呈"C"型分布,上段轴向浓度呈指数分布,与实验结果较接近。同时考察了局部位置的颗粒浓度分布及其随操作条件的变化情况,表明快速床稀相段边壁区域颗粒浓度波动较中心强烈,且对操作条件的变化敏感,回料口附近的偏流现象以及过渡渐缩段的颗粒弹溅现象均与实验观察一致。研究得到的规律可指导多段分级转化流化床的设计和优化。 展开更多
关键词 多段分级转化流化床 煤气化反应器 欧拉双流体模型 气固两相流 数值模拟
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Performance characteristics of fluidized bed syngas methanation over Ni-Mg/Al_2O_3 catalyst 被引量:1
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作者 刘姣 崔佃淼 +2 位作者 余剑 苏发兵 许光文 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第1期86-92,共7页
The performance characteristics of isothermal fluidized bed syngas methanation for substitute natural gas are investigated over a self-made Ni–Mg/Al2O3 catalyst. Via atmospheric methanation in a laboratory fluidized ... The performance characteristics of isothermal fluidized bed syngas methanation for substitute natural gas are investigated over a self-made Ni–Mg/Al2O3 catalyst. Via atmospheric methanation in a laboratory fluidized bed reactor it was clarified that the CO conversion varied in 5% when changing the space velocity in 40–120 L·g-1·h-1but the conversion increased obviously by raising the superficial gas velocity from 4 to12.4 cm·s-1. The temperature at 823 K is suitable for syngas methanation while obvious deposition of uneasyoxidizing Cγoccurs on the catalyst at temperatures around 873 K. From a kinetic aspect, the lowest reaction temperature is suggested to be 750 K when the space velocity is 60 L·g-1·h-1. Raising the H2/CO ratio of the syngas increased proportionally the CO conversion and CH4 selectivity, showing that at enough high H2/CO ratios the active sites on the catalyst are sufficient for CO adsorption and in turn the reaction with H2 for forming CH4.Introducing CO2 into the syngas feed suppresses the water gas shift and Boudouard reactions and thus increased H2 consumption. The ratio of CO2/CO in syngas should be better below 0.52 because varying the ratio from 0.52 to0.92 resulted in negligible increases in the H2 conversion and CH4 selectivity but decreased the CH4 yield.Introducing steam into the feed gas affected little the CO conversion but decreased the selectivity to CH4. The tested Ni–Mg/Al2O3 catalyst manifested good stability in structure and activity even in syngas containing water vapor. 展开更多
关键词 Syngas methanation Ni catalyst Fluidized bed Substitute natural gas Performance
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Coal Gasification in Moving Bed Reactor with a Draft Tube
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作者 刘跃进 Y.Uemura +1 位作者 K.Ijichi Y.Hatate 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1999年第2期178-181,共4页
The application of a new type of moving bed reactor with draft tube for coal gasification was investigated. Successful coal gasification experiments were achieved using the coal gasifier. Product gas containing hydrog... The application of a new type of moving bed reactor with draft tube for coal gasification was investigated. Successful coal gasification experiments were achieved using the coal gasifier. Product gas containing hydrogen as high as 60% was obtained, and the calorific value of the product of 10 MJ&middotm-3 was obtained using air as oxidant. The reaction temperature of coal gasification in the moving bed was maintained at 870 °C which was comparatively low for coal gasification. Maximum coal gasification efficiency of 92% was obtained. 展开更多
关键词 coal gasification moving bed reactor draft tube
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Conversion and reaction kinetics of coke oven gas over a commercial Fe-Mo/Al_2O_3 catalyst 被引量:2
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作者 屈一新 徐贺明 +2 位作者 赵见峰 王志彦 王亚涛 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第2期293-302,共10页
Producing methanol from coke oven gas(COG) is one of the important applications of COG. Removal of sulfur from COG is a key step of this process. Conversion and reaction kinetics over a commercial Fe-Mo/Al2O3 catalyst... Producing methanol from coke oven gas(COG) is one of the important applications of COG. Removal of sulfur from COG is a key step of this process. Conversion and reaction kinetics over a commercial Fe-Mo/Al2O3 catalyst(T-202) were studied in a continuous flow fixed bed reactor under pressures of 1.6-2.8 MPa, space time of 1.32-3.55 s and temperatures of 240-360 °C. Though the COG contains about 0.6 mol/mol H2, hydrogenation of CO and CO2 is not significant on this catalyst. The conversions of unsaturated hydrocarbons depend on their molecular structures. Diolefins and alkynes can be completely hydrogenated even at relatively low temperature and pressure. Olefins, in contrast, can only be progressively hydrogenated with increasing temperature and pressure. The hydrodesulfurization(HDS) of CS2 on this catalyst is easy. Complete conversion of CS2 was observed in the whole range of the conditions used in this work. The original COS in the COG can also be easily converted to a low level. However, its complete HDS is difficult due to the relatively high concentration of CO in the COG and due to the limitation of thermodynamics. H2 S can react with unsaturated hydrocarbons to form ethyl mercaptan and thiophene, which are then progressively hydrodesulfurized with increasing temperature and pressure. Based on the experimental observations, reaction kinetic models for the conversion of ethylene and sulfur-containing compounds were proposed; the values of the parameters in the models were obtained by regression of the experimental data. 展开更多
关键词 coke oven gas CONVERSION Fe-Mo/Al2O3 catalyst sulfur-containing compound KINETICS
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基于非均匀曳力模型的CFB循环特性研究
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作者 刘洋 霍鹏举 +1 位作者 李晓宏 祁海鹰 《工程热物理学报》 EI CAS CSCD 北大核心 2020年第6期1440-1444,共5页
为了给工业级循环流化床(CFB)煤气化反应器的运行调试提供有效的参考依据,在操作参数之一--颗粒质量循环流率Gs未知的情况下,本文采用具有宽工况普适能力的QC-EMMS非均匀曳力模型和欧拉-欧拉数值方法,模拟了提升管内的气固两相流动,准... 为了给工业级循环流化床(CFB)煤气化反应器的运行调试提供有效的参考依据,在操作参数之一--颗粒质量循环流率Gs未知的情况下,本文采用具有宽工况普适能力的QC-EMMS非均匀曳力模型和欧拉-欧拉数值方法,模拟了提升管内的气固两相流动,准确给出了该装置的循环特性,即不同流化风速下颗粒质量循环流率Gs与床存量的关系曲线,揭示了实际过程中可能存在的A类噎塞现象,以及发生噎塞前后,床内颗粒浓度分布的变化规律。研究表明,欧拉方法和QC-EMMS模型可在各类大型CFB系统运行的改进、放大和优化中发挥应有的重要作用。 展开更多
关键词 循环流化床煤气化反应器 循环特性 QC-EMMS非均匀曳力模型 A类噎塞
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Conceptual Design for a Kerosene Fuel-rich Gas-generator of a Turbopump-fed Liquid Rocket Engine 被引量:3
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作者 Min Son Jaye Koo +1 位作者 Won Kook Cho Eun Seok Lee 《Journal of Thermal Science》 SCIE EI CAS CSCD 2012年第5期428-434,共7页
A design method for a kerosene fuel-rich gas-generator of a liquid rocket engine using turbopumps to supply propellant was performed at a conceptual level. The gas-generator creates hot gases, enabling the turbine to ... A design method for a kerosene fuel-rich gas-generator of a liquid rocket engine using turbopumps to supply propellant was performed at a conceptual level. The gas-generator creates hot gases, enabling the turbine to operate the turbopumps. A chemical non-equilibrium analysis and a droplet vaporization model were used for the estimation of the burnt gas properties and characteristic chamber length. A premixed counter-flow flame analysis was performed for the prediction of the burnt gas properties, namely the temperature, the specific heat ratio and heat capacity, and the chemical reaction time. To predict the vaporization time, the Spalding model, using a single droplet in convective condition, was used. The minimum residence time in the chamber and the characteristic length were calculated by adding the reaction time and the vaporization time. Using the characteristic length, the design methods for the fuel-rich gas-generator were established. Finally, a parametric study was achieved for the effects of the O/F ratio, mass flow rate, chamber pressure, initial droplet temperature, initial droplet diameter and initial droplet velocity. 展开更多
关键词 Liquid rocket engine Conceptual design Fuel-rich gas-generator Sensitivity analysis
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Investigation of drying characteristics of low rank coal of bubbling fluidization through experiment using lab scale 被引量:2
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作者 DoMan JEON TaeJin KANG +2 位作者 HyungTaek KIM SiHyun LEE SangDo KIM 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第7期1680-1683,共4页
Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utiliz... Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utilize it in power plant. In the present work, experiments on lignite has been done using a lab scale fluidized-bed reactor. Drying lignite through fluidized-bed reactor has a higher drying rate because there is good contact between particles and gas in the fluidized-bed reactor. Fluidized-bed drying can use air of 1.5 times of the minimum fluidizing velocity performance at bubbling fluidized-bed. Experiments have been performed on coal particle sizes of 0.3-1 mm, 1-1.18 mm and 1.18-2.8 mm, with operating temperatures being 100℃, 125℃ and 150℃, respectively. It is found that fluidization has a higher drying rate due to the heat transfer rate through air velocity. Hence, moisture content in lignite can be dried to a desired value with a time interval of 10 rain. The experiment through fluidized-bed reactor is expected to be useful for saving money and time. 展开更多
关键词 low rank coal moisture content minimum fluidizing velocity bubbling fluidized-bed
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