Introduction to heat transfer

A review on microcombustion: Fundamentals, devices and applications

Dynamics of premixed hydrogen/air flames in microchannels

The article contains sections titled:



1.	Introduction	
1.1.	Types of Catalysis	
1.2.	Catalysis as a Scientific Discipline	
1.3.	Industrial Importance of Catalysis	
1.4.	History of Catalysis	
2.	Theoretical Aspects	
2.1.	Principles and Concepts	
2.1.1.	Sabatier's Principle	
2.1.2.	The Principle of Active Sites	
2.1.3.	Surface Coordination Chemistry	
2.1.4.	Modifiers and Promoters	
2.1.5.	Active Phase – Support Interactions	
2.1.6.	Spillover Phenomena	
2.1.7.	Phase-Cooperation and Site-Isolation Concepts	
2.1.8.	Shape-Selectivity Concept	
2.1.9.	Principles of the Catalytic Cycle	
2.2.	Kinetics of Heterogeneous Catalytic Reactions	
2.2.1.	Concepts of Reaction Kinetics (Microkinetics)	
2.2.2.	Application of Microkinetic Analysis	
2.2.3.	Langmuir – Hinshelwood – Hougen – Watson Kinetics	
2.2.4.	Activity and Selectivity	
2.3.	Molecular Modeling in Heterogeneous Catalysis	
2.3.1.	Density Functional Theory	
2.3.2.	Kinetic Monte Carlo Simulation	
2.3.3.	Mean-Field Approximation	
2.3.4.	Development of Multistep Surface Reaction Mechanisms	
3.	Development of Solid Catalysts	
4.	Classification of Solid Catalysts	
4.1.	Unsupported (Bulk) Catalysts	
4.1.1.	Metal Oxides	
4.1.1.1.	Simple Binary Oxides	
4.1.1.2.	Complex Multicomponent Oxides	
4.1.2.	Metals and Metal Alloys	
4.1.3.	Carbides and Nitrides	
4.1.4.	Carbons	
4.1.5.	Ion-Exchange Resins and Ionomers	
4.1.6.	Molecularly Imprinted Catalysts	
4.1.7.	Metal – Organic Frameworks	
4.1.8.	Metal Salts	
4.2.	Supported Catalysts	
4.2.1.	Supports	
4.2.2.	Supported Metal Oxide Catalysts	
4.2.3.	Surface-Modified Oxides	
4.2.4.	Supported Metal Catalysts	
4.2.5.	Supported Sulfide Catalysts	
4.2.6.	Hybrid Catalysts	
4.2.7.	Ship-in-a-Bottle Catalysts	
4.2.8.	Polymerization Catalysts	
4.3.	Coated Catalysts	
5.	Production of Heterogeneous Catalysts	
5.1.	Unsupported Catalysts	
5.2.	Supported Catalysts	
5.2.1.	Supports	
5.2.2.	Preparation of Supported Catalysts	
5.3.	Unit Operations in Catalyst Production	
6.	Characterization of Solid Catalysts	
6.1.	Physical Properties	
6.1.1.	Surface Area and Porosity	
6.1.2.	Particle Size and Dispersion	
6.1.3.	Structure and Morphology	
6.1.4.	Local Environment of Elements	
6.2.	Chemical Properties	
6.2.1.	Surface Chemical Composition	
6.2.2.	Valence States and Redox Properties	
6.2.3.	Acidity and Basicity	
6.3.	Mechanical Properties	
6.4.	Characterization of Solid Catalysts under Working Conditions	
6.4.1.	Temporal Analysis of Products (TAP Reactor)	
6.4.2.	Use of Isotopes	
6.4.3.	Use of Substituents, Selective Feeding, and Poisoning	
6.4.4.	Spatially Resolved Analysis of the Fluid Phase over a Catalyst	
6.4.5.	Spectroscopic Techniques	
7.	Design and Technical Operation of Solid Catalysts	
7.1.	Design Criteria for Solid Catalysts	
7.2.	Catalytic Reactors	
7.2.1.	Classification of Reactors	
7.2.2.	Laboratory Reactors	
7.2.3.	Industrial Reactors	
7.2.4.	Special Reactor Types and Processes	
7.2.5.	Simulation of Catalytic Reactors	
7.3.	Catalyst Deactivation and Regeneration	
7.3.1.	Different Types of Deactivation	
7.3.2.	Catalyst Regeneration	
7.3.3.	Catalyst Reworking and Disposal	
8.	Industrial Application and Mechanisms of Selected Technically Relevant Reactions	
8.1.	Synthesis Gas and Hydrogen	
8.2.	Ammonia Synthesis	
8.3.	Methanol and Fischer – Tropsch Synthesis	
8.3.1.	Methanol Synthesis	
8.3.2.	Fischer – Tropsch Synthesis	
8.4.	Hydrocarbon Transformations	
8.4.1.	Selective Hydrocarbon Oxidation Reactions	
8.4.1.1.	Epoxidation of Ethylene and Propene	
8.4.1.2.	Ammoxidation of Hydrocarbons	
8.4.2.	Hydroprocessing Reactions	
8.5.	Environmental Catalysis	
8.5.1.	Catalytic Reduction of Nitrogen Oxides from Stationary Sources	
8.5.2.	Automotive Exhaust Catalysis

Heterogeneous Catalysis and Solid Catalysts

This review discusses the role of laser diagnostics in combustion science and technology. In its first part, it may guide understanding of advanced diagnostic methods, and is particularly helpful for non-specialized experimentalists. Various challenges for future developments and applications of optical combustion diagnostics are highlighted. In the second part of this review, flame-wall interactions are selected for a more in-depth discussion. Flame-wall interactions are scientifically interesting and are of great importance to any enclosed practical combustion process. Following a description of current understanding, the focus is on using optical diagnostics to probe thermal, fluidic, and chemical properties of head-on and sidewall quenching. The review ends with a discussion of issues and implications for future experimental research and specific diagnostic needs.

Advanced laser diagnostics for an improved understanding of premixed flame-wall interactions

Two-dimensional modelling for catalytically stabilized combustion of a lean methane-air mixture with elementary homogeneous and heterogeneous chemical reactions

The homogeneous ignition of lean methane-air mixtures was investigated numerically and experimentally in a laminar plane channel flow configuration established by two externally heated catalytically active (Pt-coated) ceramic plates, 250 mm long by 100 mm wide, place 7 mm apart. Preheated fuel-air mixtures with equivalence ratios of 0.31 and 0.37 and uniform velocities of 1 and 2 m/s were examined, resulting in incoming Reynolds numbers ranging from 190 to 380. Planar laser-induced fluorescence (PLIF) was used to map the OH concentration field along the streamwise direction and thermocouples to monitor both catalyst plate temperatures. The numerical predictions included a two-dimensional elliptic model with detailed heterogeneous and homogeneous chemical reactions. The homogeneous ignition location strongly depends on the incoming velocity and mildly on the equivalence ratio. Following homogeneous ignition, a very stable V-shaped flame is formed in all cases. Measured and predicted flame sweep angles, OH levels, and the post-flame OH relaxation are in good agreement with each other, while the homogeneous ignition distance is predicted within 9% in all cases. The homogeneous ignition location is shown to be better identified with changes of averaged (over the channel cross section) quantities rather than with changes in local wall gradients. The overall model performance suggests that the employed surface scheme is capable of capturing the coupling between surface and gaseous chemistries leading to homogeneous ignition. Experiments and predictions were also carried out with noncatalytic plates. The resulting flame is unstable and asymmetric, clearly showing the stability advantages of catalytically assisted combustion.

/pdf/homogeneous-ignition-of-methane-air-mixtures-over-platinum-4gpmhv0073.pdf

Urs Dogwiler

Papers

Two-dimensional modelling for catalytically stabilized combustion of a lean methane-air mixture with elementary homogeneous and heterogeneous chemical reactions

Homogeneous ignition of methane-air mixtures over platinum: Comparison of measurements and detailed numerical predictions

Numerical modelling of turbulent catalytically stabilized channel flow combustion