該論文采用實(shí)驗(yàn)與計(jì)算流體力學(xué)（CFD）模擬相結(jié)合的方法,研究在中溫條件下高固含率牛糞厭氧發(fā)酵過程。牛糞呈現(xiàn)非牛頓幕律流體特性。實(shí)驗(yàn)裝置為中試規(guī)模的攪拌發(fā)酵罐,水力停留時(shí)間（HRT）為30天。采用六槳葉渦輪攪拌槳對(duì)發(fā)酵液進(jìn)行混合,槳葉傾斜角為45°。實(shí)驗(yàn)采用非攪拌混合方式,設(shè)置了三種攪拌強(qiáng)度,速度分別為50、100和150rpm,旨在確定最優(yōu)的攪拌強(qiáng)度（以最低能耗提高厭氧發(fā)酵效率）。由甲烷產(chǎn)量和產(chǎn)氣率可知,攪拌強(qiáng)度100rpm比50rpm的產(chǎn)氣率高,且這兩個(gè)攪拌強(qiáng)度的產(chǎn)氣率均高于150rpm的。與攪拌強(qiáng)度50rpm和100rpm的產(chǎn)氣實(shí)驗(yàn)相比,150rpm時(shí)的甲烷產(chǎn)量分別降低了18%和21%。實(shí)驗(yàn)結(jié)果表明,攪拌強(qiáng)度為100rpm是最佳的經(jīng)濟(jì)轉(zhuǎn)速（以千瓦時(shí)為單位的凈發(fā)電量）,其次是50rpm與150rpm。CFD模擬預(yù)測(cè)的非牛頓幕律流體攪拌能耗與實(shí)驗(yàn)測(cè)量值一致。實(shí)驗(yàn)和CFD計(jì)算結(jié)果表明,最少的攪拌次數(shù)為每天一次,可以節(jié)省99%的甲烷輸出產(chǎn)能（僅1%的甲烷輸出產(chǎn)能用于攪拌）。通過進(jìn)一步的CFD模擬優(yōu)化,當(dāng)攪拌強(qiáng)度由50rpm增加到100rpm,增幅設(shè)定為10rpm;結(jié)果表明:以甲烷產(chǎn)量為目標(biāo)... 

【文章來源】：江蘇大學(xué)江蘇省

【文章頁數(shù)】：235 頁

【學(xué)位級(jí)別】：博士

【文章目錄】：
摘要
Abstract
Annotations
Chapter 1 Introduction
    1.1 Background
    1.2 Aims and Objectives
    1.3 Specific Objectives
    1.4 Knowledge Gaps
    1.5 Research Scope
    1.6 Anaerobic Digestion
        1.6.1 Advantages of Anaerobic Digestion
        1.6.2 Anaerobic Biochemical Processes
    1.7 Environmental Factors
        1.7.1 Temperature
        1.7.2 pH
        1.7.3 Alkalinity
        1.7.4 VFAs Concentration
        1.7.5 Nutrients and Trace Elements
        1.7.6 Hydraulic Retention Time and Solids Retention Time
        1.7.7 Organic Loading Rate
    1.8 Characterization of Manure
    1.9 Research Methods
        1.9.1 The Experimental Setup
        1.9.2 Dairy Cattle Manure
        1.9.3 Inoculum for the Startup Process
Chapter 2 Influence of Mixing on Anaerobic Digestion Efficiency in Stirred Tank Digesters
    2.1 Background
    2.2 Comparison of Mixing Intensity and Power Requirements of Impeller, SlurryRecirculation and Gas Mixing
    2.3 Effect of Mixing/Shear Intensity on Microorganisms
    2.4 Effect of Mixing Intensity on AD Efficiency
    2.5 Effects of Mixing Mode and Duration on AD Efficiency
    2.6 Effects of Mixing on Scum, Crust and Foam Formation
    2.7 Effects of Mixing on the HRT/SRT
    2.8 Effect of Mixing on VFA
    2.9 Summary and Analysis of Different Observations
    2.10 Brief Summary
Chapter 3 Influence of Minimal Mixing Intensity on High-Solids Anaerobic Digestion Energy Efficiency
    3.1 Background
    3.2. Materials and Methods
        3.2.1 Non-Mixed Experiment
        3.2.2 Effect of Mixing Intensity
        3.2.3 Effect of Change in HRT and OLR
        3.2.4 Data Comparison
    3.3 Results and Discussion
        3.3.1 Comparison of the Methane Yield and Specific Methane Production Rate
        3.3.2 Comparison of the Net Energy Production
        3.3.3 The Effect of OLR and HRT
    3.4 Brief Summary
Chapter 4 Predicting the Methane Productivity and Specific Methane Production Rate
    4.1 Background
        4.1.1 Mathematical Modeling
    4.2 Materials and Methods
        4.2.1 Modeling the Startup Process
        4.2.2 Gompertz Growth
        4.2.3 First Order Kinetics
        4.2.4 Modeling the Effects of Mixing Intensities on HSAD
    4.3 Results and Discussion
        4.3.1 Specific Biogas and Methane Production Rate of the Startup Process
        4.3.2 Gompertz Growth Model Fit
        4.3.3 First Order Kinetics
        4.3.4 Modeling the Effect of Mixing Intensities using the Stoichiometric Method
        4.3.5 Modeling the Effects of Mixing Intensities on HSAD using Karim's Model
        4.3.6 Simple Linear Model
    4.4 Brief Summary
Chapter 5 Physical and Rheological Properties of Cattle Manure
    5.1 Background
    5.2 Review of Equations and Values for Consistency Coefficient
    5.3 Review of Equations and Values for Flow Behavior Index
    5.4 summarize the ranges of reported values of n as a function of manure type, TS, temperature and shear rate (γ).
    5.5 Brief Summary
Chapter 6 CFD Simulations of Mixing for High-Solids Anaerobic Digestion of Dairy Manure in a Pilot-Scale
    6.1 Background
    6.2 Model Development
        6.2.1 Assumptions
        6.2.2 Governing Equations
        6.2.3 Numerical Approach
    6.3 Experimental Setup
    6.4 Results and Discussion
        6.4.1 Grid Independence Study
        6.4.2 Model Validation
        6.4.3 Qualifying Flow Patterns
        6.4.4 Quantifying Flow Patterns
        6.4.5 Shear Rate
        6.4.6 Turbulent Kinetic Energy
        6.4.7 Velocity Gradient
        6.4.8 Predicting the Influence of Flow Hydrodynamics on Floc Breakup and Growth.
        6.4.9 Mixing Energy Level(MEL)
        6.4.10 Mixing Time
        6.4.11 Local Mixing Time
        6.4.12 Global Mixing Time
        6.4.13 Time Evolution of Tracer Concentration
        6.4.14 Net Energy Production
        6.4.15 Optimization of the Mixing Intensity
        6.4.16 The Effects of Total Solids Concentration on the Velocity Distributions and thePower Consumption.
    6.5 Brief Summary
Chapter 7 Conclusion
References
Acknowledgements
List of Academic Papers Published during the Study



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