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期刊论文 49

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Experimental study on the stratum applicability and mechanisms of bubbleslurry for earth pressure balance

《结构与土木工程前沿(英文)》   页码 1387-1399 doi: 10.1007/s11709-023-0005-y

摘要: Soil conditioning is essential for addressing the stratum applicability problem of earth pressure balance (EPB) shields. Under high water pressures, EPB shields spew water and soil when excavating coarse-grained strata. Typically, foam combined with polymers and slurry is used to solve spewing. However, in current techniques, slurry, foam, and the other agents are mixed with soil separately, their synergistic effect is seldom realized. In this study, an anionic surfactant was used to foam in bentonite slurry to form bubble–slurry to maximize the synergy between bubbles and slurry. The slump, volume stability, and permeability test of bubble–slurry-conditioned sand was conducted to examine the conditioning effect, and the stratum applicability of bubble–slurry was determined from the perspective of permeability. It was found that the conditioning effect of bubble–slurry in coarse gravel soil was excellent and could expand the applicability of EPB shields. The main stabilization mechanism of bubble–slurry is that bentonite particles provide a space barrier for bubbles. And three seepage modes of bubble–slurry-conditioned sand were innovatively defined, and the occurrence conditions of the three seepage modes were analyzed according to the permeability coefficient of sand, initial dynamic shear force of bubble–slurry, and hydraulic gradient.

关键词: EPB shield     bubble–slurry     soil conditioning     stability     permeability    

Study on direct alcohol/ether fuel synthesis process in bubble column slurry reactor

Zhen CHEN, Haitao ZHANG, Weiyong YING, Dingye FANG

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 461-471 doi: 10.1007/s11705-010-0517-6

摘要: The recent studies of direct alcohol/ether synthesis process in slurry reactors were reviewed, and the research work in our laboratory was carried out in this paper. a global kinetics model for direct dimethyl ether (DME) synthesis from syngas over a novel Cu-Zn-Al-Zr slurry catalyst was established according to the total of 25 experimental data, and a steady-state one-dimensional mathematical model was further developed in bubble column slurry reactor (BCSR), which was assumed that the bubble phase was plug flow, and the liquid phase was fully mixed flow. The numerical simulations of reactor design of 100000 t/a dimethyl ether pilot plant indicate that higher pressure and lower temperature were favorable to the increase of CO conversion, selectivity of dimethyl ether, product yield and height of slurry bed. The optimal operating conditions for DME synthesis process were obtained: reaction temperature at 240°C, reactor pressure at 5 MPa and reactor diameter of 2.5 m.

关键词: syngas     alcohol/ether fuel     slurry catalyst     bubble column slurry reactor     global kinetics     mathematical model    

Experimental study on bubble behavior and CFD simulation of large-scale slurry bubble column reactor

Haoyi SUN, Tao LI, Weiyong YING, Dingye FANG

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 515-522 doi: 10.1007/s11705-010-0516-7

摘要: Slurry bubble column reactors (SBCR) is a three-phase fluidized reactor with outstanding advantages compared with other reactors and is difficult to scale-up due to lack of information on hydrodynamics and mass transfer over a wide range of operating conditions of commercial interest. In this paper, an experiment was conducted to investigate the bubble behavior in SBCR with a height of 5600 mm and an interior diameter of 480 mm. Bubble rise velocity, bubble diameter, and gas holdup in different radial and axial positions are measured in SBCR using four-channel conductivity probe. Tap water, air, and glass beads (mean diameter 75–150 μm) are used as liquid, gas, and solid phases, respectively. It shows that hydrodynamic parameters have good regularity in SBCR. Moreover, a commercial computational fluid dynamics (CFD) package, Fluent, was used to simulate the process in SBCR. The simulations were carried out using axi-symmetric 2-D grids. Data obtained from experiment and CFD simulation are compared, and results show that the tendency of simulation is almost uniform with the experiment, which can help to obtain further understanding about multiphase flow process and establish a model about the synthesis of alcohol ether fuel in SBCR.

关键词: SBCR     four-channel conductivity probe     hydrodynamics     CFD    

气升式浆态床反应器的过程强化 Review

耿淑君, 毛在砂, 黄青山, 杨超

《工程(英文)》 2021年 第7卷 第3期   页码 304-325 doi: 10.1016/j.eng.2021.03.002

摘要:

气升式浆态床反应器是一种重要的气-液-固多相反应器,包括鼓泡塔反应器和环流反应器。这些反应器具有剪切应力低、混合程度好、传质/传热能力强、成本低等优点,已被广泛应用于许多工业过程,尤其是生物发酵和能源化工领域。为了进一步提高浆态床反应器的性能(即混合和传质/传热性能)和满足工业应用要求(如温度控制、减少返混和产品分离等),浆态床反应器的过程强化至关重要。首先,本文回顾了这两种反应器在强化混合和传质/传热方面的最新研究进展。然后,总结了浆态床反应器在连续生产时混合与分离的过程强化方法,其中,由于具有高效率和低成本的优点,推荐采用将环流反应器内的定向流动与水力旋流器的简单固-液分离相结合的过程强化技术。接着,系统地讨论了浆态床反应器所面临的问题和挑战,包括流型判别、气体分布器设计、固体颗粒影响及其他问题。本文还介绍了应用计算流体力学对浆态床反应器进行数值模拟的研究进展,讨论了建模的难点。最后,对工业浆态床反应器的设计进行总结和展望。

关键词: 浆态床反应器     气升式搅拌     鼓泡塔     环流反应器     过程强化     固体颗粒    

Experimental study on slurry-induced fracturing during shield tunneling

Teng WANG, Dajun YUAN, Dalong JIN, Xinggao LI

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 333-345 doi: 10.1007/s11709-021-0718-8

摘要: Facial support in slurry shield tunneling is provided by slurry pressure to balance the external earth and water pressure. Hydraulic fracturing may occur and cause a significant decrease in the support pressure if the slurry pressure exceeds the threshold of the soil or rock material, resulting in a serious face collapse accident. Preventing the occurrence of hydraulic fracturing in a slurry shield requires investigating the effects of related influencing factors on the hydraulic fracturing pressure and fracture pattern. In this study, a hydraulic fracturing apparatus was developed to test the slurry-induced fracturing of cohesive soil. The effects of different sample parameters and loading conditions, including types of holes, unconfined compressive strength, slurry viscosity, and axial and circumferential loads, on the fracturing pressure and fracture dip were examined. The results indicate that the fracture dip is mainly affected by the deviator stress. The fracturing pressure increases linearly with the increase in the circumferential pressure, but it is almost independent of the axial pressure. The unconfined compressive strength of soil can reflect its ability to resist fracturing failure. The fracturing pressure increases with an increase in the unconfined compressive strength as well as the slurry viscosity. Based on the test results, an empirical approach was proposed to estimate the fracturing pressure of the soil.

关键词: slurry shield tunneling     hydraulic fracturing test     fracturing pressure     fracture dip     unconfined compressive strength     slurry viscosity    

Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

《化学科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 162-172 doi: 10.1007/s11705-009-0267-5

摘要: Bubble columns are widely used in chemical and biochemical processes due to their excellent mass and heat transfer characteristics and simple construction. However, their fundamental hydrodynamic behaviors, which are essential for reactor scale-up and design, are still not fully understood. To develop design tools for engineering purposes, much research has been carried out in the area of computational fluid dynamics (CFD) modeling and simulation of gas-liquid flows. Due to the importance of the bubble behavior, the bubble size distribution must be considered in the CFD models. The population balance model (PBM) is an effective approach to predict the bubble size distribution, and great efforts have been made in recent years to couple the PBM into CFD simulations. This article gives a selective review of the modeling and simulation of bubble column reactors using CFD coupled with PBM. Bubble breakup and coalescence models due to different mechanisms are discussed. It is shown that the CFD-PBM coupled model with proper bubble breakup and coalescence models and interphase force formulations has the ability of predicting the complex hydrodynamics in different flow regimes and, thus, provides a unified description of both the homogeneous and heterogeneous regimes. Further study is needed to improve the models of bubble coalescence and breakup, turbulence modification in high gas holdup, and interphase forces of bubble swarms.

关键词: bubble column     computational fluid dynamics     bubble breakup and coalescence     population balance model     bubble size distribution    

The role of single deformed bubble on porous foam tray with submerged orifices on the mass transfer enhancement

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2127-2143 doi: 10.1007/s11705-023-2363-3

摘要: Foam trays with porous submerged orifices endow bubbles uniformly distributed, which are considered attractive column internals to enhance the gas-liquid mass transfer process. However, its irregular orifice and complex gas-liquid flow make it lack pore-scale investigations concerning the transfer mechanism of dynamic bubbling. In this work, the actual porous structure of the foam tray is obtained based on micro computed tomography technology. The shape, dynamic, and mass transfer of rising bubbles at porous orifices are investigated using the volume of fluid and continue surface force model. The results demonstrate that the liquid encroaching on the gas channels causes the increasing orifices velocity, which makes the trailing bubble easily detach from the midst of the leading bubble and causes pairing coalescence. Additionally, we found that the central breakup regimes significantly improve the gas-liquid interface area and mass transfer efficiency. This discovery exemplifies the mechanism of mass transfer intensification for foam trays and serves to promote its further development.

关键词: bubble formation     porous submerged orifices     process intensification     foam tray    

Copper fractal growth during recycling from waste printed circuit boards by slurry electrolysis

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1405-7

摘要:

• Copper fractal growth was observed during WPCBs recycling by slurry electrolysis.

关键词: Dendritic copper     Fractal growth     WPCBs     Slurry electrolysis    

Synchronous observation of rising soluble bubble through quiescent solution

Yifu ZHANG , Shuai TIAN , Weizhong LI , Yongchen SONG ,

《能源前沿(英文)》 2009年 第3卷 第3期   页码 307-312 doi: 10.1007/s11708-009-0028-7

摘要: An experimental method using computer image processing technology (CIPT) was proposed to observe and investigate the velocity, deformation, heat and mass transfer, etc. of a rising soluble gas (CO) bubble through a quiescent hot water. A model was set up to describe the behavior of the bubble in a visual experimental system in which a high-speed camera rose instantaneously with the movement of the bubble. A series of trajectory videos about the bubble were recorded by a computer linked to the camera. The trajectory, volume changes and rate of mass transfer of the bubble were obtained by the CIPT. It is found that the single bubble follows a rolling trajectory at the initial stage when there is mass transfer. With the volume decreasing, the disturbed behavior of the bubble becomes tempered. When the rising velocity of the bubble reaches the maximum, the velocity is nearly at a constant. The experimental and analysis results show that this method is useful for the research on the mass transfer and the movement of rising bubbles in liquid.

关键词: soluble bubble     mass transfer     synchronous observation     computer image processing    

Kinetic study of hydrodesulfurization of coker gas oil in a slurry reactor

Haiding XIANG, Tiefeng WANG

《化学科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 139-144 doi: 10.1007/s11705-013-1323-8

摘要: Coker gas oil (CGO) is a poor-quality feedstock for fluidized bed catalytic cracking (FCC) or hydrocracking. The pretreatment of CGO, especially hydrotreating, can significantly improve the product quality and protect the catalyst. In this work, we studied the hydrodesulfurization (HDS) of CGO in a slurry reactor. All the experiments were carried out in an autoclave using a NiMo/Al O catalyst at reaction temperature 340°C–400°C, pressure 6–10 MPa, and stirring speed 800 r·min , with hydrogen-to-oil ratio in the range of 500–1500. The effects of the operating parameters on the desulfurization ratio were investigated and discussed. A macro reaction kinetic model was established for the HDS of CGO in the slurry reactor.

关键词: coker gas oil     hydrodesulfurization     slurry reactor     reaction kinetic model    

Investigation of bubble diameter and flow regime between water and dilute aqueous ethanol solutions in

Baharak SAJJADI, Mostafa Keshavarz MORAVEJI, Reza DAVARNEJAD

《化学科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 194-202 doi: 10.1007/s11705-010-1019-2

摘要: In this study, the effect of ethanol addition into pure water and its concentration on bubble diameter, gas hold-up and flow regimes were investigated in an airlift reactor. Air and water with ethanol (concentration ranging from 0%–1%, v/v) were as dispersed and continuous phases, respectively. Superficial gas velocity was considered as an effective parameter. Bubble size distribution was measured by photography and picture analysis at various concentrations of ethanol and various velocities of gas. Alcohol concentration enhancement caused bubble diameter to decrease. Furthermore, the bubbles diameter in pure water was nearly 4 times higher than that of ethanol with concentration of 1% (v/v) and also was 3.4 times higher than that of ethanol with concentration of 0.25% (v/v) at the highest aeration gas velocity inlet. For ethanol solutions in lower superficial gas velocity, a homogenous flow regime was observed. This trend continued to inlet gas velocity of about 0.4 cm/s. The transition flow regime occurred after this datum although in pure water, a homogenous flow regime was observed up to a superficial gas velocity of 0.7 cm/s. The gas hold-up in dilute ethanol solutions were more than (around 2 times) that of pure water and increased with increasing concentration of ethanol in those solutions.

关键词: airlift rector     bubble diameter     gas hold-up     flow regime     ethanol    

Numerical simulation on flow of ice slurry in horizontal straight tube

Shengchun LIU,Ming SONG,Ling HAO,Pengxiao WANG

《能源前沿(英文)》 2021年 第15卷 第1期   页码 201-207 doi: 10.1007/s11708-017-0451-0

摘要: Numerical simulation on flow of ice slurry in horizontal straight tubes was conducted in this paper to improve its transportation characteristics and application. This paper determined the influence of the diameter and length of tubes, the ice packing factors (IPF) and the flow velocity of ice slurry on pressure loss by using numerical simulation, based on two-phase flow and the granular dynamic theory. Furthermore, it was found that the deviation between the simulation results and experimental data could be reduced from 20% to 5% by adjusting the viscosity which was reflected by velocity. This confirmed the reliability of the simulation model. Thus, two mathematical correlations between viscosity and flow velocity were developed eventually. It could also be concluded that future rheological model of ice slurry should be considered in three sections clarified by the flow velocity, which determined the fundamental difference from single-phase fluid.

关键词: ice slurry     horizontal tubes     numerical simulation     pressure drop     viscosity model    

Development and demonstration plant operation of an opposed multi-burner coal-water slurry gasification

WANG Fuchen, ZHOU Zhijie, DAI Zhenhua, GONG Xin, YU Guangsuo, LIU Haifeng, WANG Yifei, YU Zunhong

《能源前沿(英文)》 2007年 第1卷 第3期   页码 251-258 doi: 10.1007/s11708-007-0035-5

摘要: The features of the opposed multi-burner (OMB) gasification technology, the method and process of the research, and the operation results of a pilot plant and demonstration plants have been introduced. The operation results of the demonstration plants show that when Beisu coal was used as feedstock, the OMB CWS gasification process at Yankuang Cathy Coal Co. Ltd had a higher carbon conversion of 3%, a lower specific oxygen consumption of about 8%, and a lower specific carbon consumption of 2%–3% than that of Texaco CWS gasification at the Lunan Fertilizer Plant. When Shenfu coal was used as feedstock, the OMB CWS gasification process at Hua-lu Heng-sheng Chemical Co. Ltd had a higher carbon conversion of more than 3%, a lower specific oxygen consumption of about 2%, and a lower specific coal consumption of about 8% than that of the Texaco CWS gasification process at Shanghai Coking & Chemical Corporation. The OMB CWS gasification technology is proven by industrial experience to have a high product yield, low oxygen and coal consumption and robust and safe operation.

Application of gamma-ray attenuation technology in density measurement of a slurry reactor

Jian XU, Weisheng WEI, Kai ZHANG

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 486-490 doi: 10.1007/s11705-010-0509-6

摘要: Axial density profile of the gas-liquid-solid mixture in a slurry bubble column was measured by gamma-ray attenuation technology. Several measures for improving measurement precision were presented based on the discussion on attenuation law. It was found that the response frequency and the ray intensity should be as high as possible to improve the measurement precision. The mass absorption coefficient depended on not the object’s thickness but the location where the object was placed between the ray source and the detector. The results showed that the density in the column decreases with the increase of column height, which indicates that the measurement by gamma-ray attenuation is reasonable.

关键词: slurry reactor     axial density distribution     gamma-ray attenuation technology    

砂卵石条件下泥水分离技术研究与应用

王广余,孙善辉,苏清贵

《中国工程科学》 2010年 第12卷 第12期   页码 41-45

摘要:

通过北京铁路北京站至北京西站地下直径线工程泥水处理系统的研究与应用实践经验,总结了城市繁华地段砂卵石条件下大直径盾构泥水分离应用技术,希望对类似工程有借鉴作用。

关键词: 泥水盾构     泥水分离     压滤    

标题 作者 时间 类型 操作

Experimental study on the stratum applicability and mechanisms of bubbleslurry for earth pressure balance

期刊论文

Study on direct alcohol/ether fuel synthesis process in bubble column slurry reactor

Zhen CHEN, Haitao ZHANG, Weiyong YING, Dingye FANG

期刊论文

Experimental study on bubble behavior and CFD simulation of large-scale slurry bubble column reactor

Haoyi SUN, Tao LI, Weiyong YING, Dingye FANG

期刊论文

气升式浆态床反应器的过程强化

耿淑君, 毛在砂, 黄青山, 杨超

期刊论文

Experimental study on slurry-induced fracturing during shield tunneling

Teng WANG, Dajun YUAN, Dalong JIN, Xinggao LI

期刊论文

Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

期刊论文

The role of single deformed bubble on porous foam tray with submerged orifices on the mass transfer enhancement

期刊论文

Copper fractal growth during recycling from waste printed circuit boards by slurry electrolysis

期刊论文

Synchronous observation of rising soluble bubble through quiescent solution

Yifu ZHANG , Shuai TIAN , Weizhong LI , Yongchen SONG ,

期刊论文

Kinetic study of hydrodesulfurization of coker gas oil in a slurry reactor

Haiding XIANG, Tiefeng WANG

期刊论文

Investigation of bubble diameter and flow regime between water and dilute aqueous ethanol solutions in

Baharak SAJJADI, Mostafa Keshavarz MORAVEJI, Reza DAVARNEJAD

期刊论文

Numerical simulation on flow of ice slurry in horizontal straight tube

Shengchun LIU,Ming SONG,Ling HAO,Pengxiao WANG

期刊论文

Development and demonstration plant operation of an opposed multi-burner coal-water slurry gasification

WANG Fuchen, ZHOU Zhijie, DAI Zhenhua, GONG Xin, YU Guangsuo, LIU Haifeng, WANG Yifei, YU Zunhong

期刊论文

Application of gamma-ray attenuation technology in density measurement of a slurry reactor

Jian XU, Weisheng WEI, Kai ZHANG

期刊论文

砂卵石条件下泥水分离技术研究与应用

王广余,孙善辉,苏清贵

期刊论文