Industrial and Process Furnaces: Principles, Design and Operation

Front Cover
INDUSTRIAL AND PROCESS FURNACES
Industrial and Process Furnaces: Principles, Design and Operation
Copyright
Dedication
Contents
Foreword to third edition
Foreword to second edition
Foreword to first edition
Preface to third edition
Preface to the second edition
Preface to first edition
Acknowledgements
List of figures
List of tables
1 - Introduction
1.1 What is a furnace?
1.1.1 Furnace outline
1.1.2 Furnace classification
1.1.3 Principal objectives of furnace designers and operators
1.2 Where are furnaces used? Brief review of current furnace applications and technology
1.2.1 Ceramics, brick making and pottery
1.2.2 Cement and lime
1.2.3 Glass making
1.2.4 Metal ore smelting
1.2.5 Metal refining
1.2.6 Flash and fluid bed furnaces
1.2.7 Metal physical processing
1.2.8 Incinerators and resource recovery furnaces
1.2.9 Furnaces with reducing atmospheres
1.2.10 Oil refining and petrochemical furnaces
1.3 Drivers for improved efficiency
1.4 Concluding remarks
References
2 - The combustion process
2.1 Simple combustion chemistry
2.1.1 The complete oxidation of carbon
2.1.2 The complete oxidation of hydrogen
2.1.3 The incomplete oxidation of carbon
2.1.4 The oxidation of carbon monoxide
2.2 Combustion calculations
2.3 Chemical reaction kinetics
2.3.1 Types of reactions
2.3.2 Reaction rate theory
2.3.3 Reaction rate behaviour
2.3.4 Burning droplets and particles
2.4 The physics of combustion
2.4.1 The role of primary air
2.4.2 The role of swirl flows
2.4.3 Turbulence in jets
2.4.4 Secondary flow aerodynamics
2.4.5 Effect of excess air on fuel consumption
2.4.6 Multiple burner installations
Nomenclature for chapter 2
References
3 - Fuels for furnaces
Determining the calorific value of a fuel
3.1 Manufactured gaseous fuels
3.1.1 Pyrolysis
3.1.2 Gasification
Gasification equipment
3.1.3 Steam reforming
3.1.4 Electrolysis
3.2 Natural gas
3.3 Properties of gaseous fuels
3.3.1 Wobbe number or index
3.3.2 Flammability limits
Minimum flammable concentration
Maximum flammable concentration
Maximum permissible oxygen concentration to prevent ignition
Calculation of the flammable limits for mixtures of gases
Influence of temperature and pressure on the limits
3.3.3 Flame radiation from gaseous fuels
3.4 Liquid fuels
3.5 Solid fuels
3.5.1 Ash
3.6 Biomass based fuels
3.7 Waste fuels
3.7.1 Waste properties and their potential effect on the combustion process, product quality, etc.
Calorific value
Contaminants
Elemental chemical analysis
Effect on furnace air requirement and flue gas volumes
Effect on flame heat release profile
Waste storage and handling
Environmental effects
Concluding remarks on waste fuels
3.8 Choice of fuel
3.8.1 Furnace performance
Heat transfer
Furnace atmosphere
Flexibility of operation
Effect of ash
Refractory life
Fuel cost and security of supply
Fuel Handling system capital and running costs
3.9 Safety
3.10 Emissions
Nomenclature for chapter 3
References
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4 - An introduction to heat transfer in furnaces
4.1 Conduction
4.1.1 Steady state conduction
4.1.2 Transient conduction
Analytical approach
Numerical approach
4.2 Convection
4.2.1 Dimensional analysis
4.2.2 Application of dimensionless numbers to convective heat transfer
4.2.3 Evaluating convective heat transfer coefficients
4.2.4 High temperature convective heat transfer
4.3 Radiation
4.3.1 Physical basics of radiative exchange
4.3.2 Emissivity and absorptivity
4.3.3 View factors
Equivalent grey surface
4.3.4 Mean beam length
4.4 Electrical heating
4.4.1 Resistance heating
Direct resistance heating
Indirect resistance heating
4.4.2 Arc heating
Electrode devices
Electrodeless devices
4.4.3 Induction heating
4.4.4 Dielectric heating
4.4.5 Infra-red heating
Nomenclature used in chapter
References
4 . Appendix 4A Table of emissivity data
5 - Flames and burners for furnaces
5.1 Types of flame
5.1.1 Premixed flames
5.1.2 Turbulent jet diffusion flames
5.1.3 Heterogenous combustion
Atomisation of liquid fuels and pulverisation of coal
The importance of drop and particle size
5.2 Function of a burner and basics of burner design
5.2.1 The essential importance of heat flux profiles
5.2.2 Flame stabilisation
5.3 Gas burners
5.3.1 Premixed burners
Effect of excess air (mixture ratio) on flame temperature
Radiant wall burners
Use of premix burners in low NOx applications
Safety issues with premix burners
Size limitations
5.3.2 Turbulent jet diffusion burners
5.3.3 Precessing jet diffusion burners
5.3.4 Gas nozzle design
Determining the fuel gas nozzle port area
Determining the drilling pattern
Determining the gas mixture nozzle port area for premix nozzles
5.4 Oil burners
5.4.1 Turndown
5.4.2 Atomisers
Pressure jet atomisers
Twin fluid atomisers
5.5 Pulverised coal burners
5.6 Burners for biomass and waste-based fuels
5.6.1 Burners for liquid wastes
5.6.2 Burners for solid wastes
Finely divided wastes with high calorific value
Fuel/air mixing
Coke particle residence time
High temperature zone close to the burner nozzle
Gas nozzle
Oil sprayer
Operational results
Burners for plastic wastes and solid biomass
Concluding remarks on waste fuel burners
5.7 Furnace aerodynamics
Burner and furnace airflow patterns
5.7.1 Single burner systems
Package burner installations
Rotary kilns and driers etc.
5.7.2 Multiple burner systems
5.7.3 Combustion air duct design
5.7.4 Common windbox and plenum design
5.8 Combustion system scaling
5.8.1 Example of combustion system scaling
5.9 Furnace noise
5.9.1 Combustion roar
5.9.2 Nozzle and turbulent jet noise
5.9.3 Fan noise
5.9.4 Pipe and valve noise
5.9.5 Furnace noise attenuation
5.9.6 Combustion driven oscillations
Nomenclature for chapter 5
References
6 . Combustion and heat transfer modelling
6.1 Physical modelling
6.1.1 Thring-Newby parameter
6.1.2 Craya-Curtet parameter
6.1.3 Becker throttle factor
6.1.4 Curtet number
6.1.5 Relationship between scaling parameters
6.1.6 Determining the required model flows
6.1.7 Applying the scaling parameter
6.1.8 Applying a post measurement correction
6.2 Mathematical modelling
6.2.1 Simple well stirred furnace models
6.2.2 Long furnace models
6.2.3 Two and three dimensional zone models
6.2.4 Computational fluid dynamics models
Computational domain (grid) of CFD models
Convergence of CFD models
6.2.5 Particle drag in combustion systems
6.2.6 Enhancement to CFD models
6.3 Application of modelling to furnace design
Nomenclature
References
7 - Fuel preparation and handling systems
7.1 Gas valve trains
7.1.1 Safety shutoff systems
Double block and bleed
Leak testing and proving
7.1.2 Gaseous fuel system safety
7.2 Fuel oil handling systems
7.2.1 Storage, pumping and heating
7.2.2 Oil valve trains
7.3 Pulverised coal handling and firing systems
7.3.1 Raw coal bunkers and feeders
7.3.2 Coal grinding and drying
Coal drying characteristics
7.3.3 Coal mills
Ball mills
Vertical spindle mills
High speed mills
7.3.4 Coal mill grinding capacity
Coal fineness
Coal dryness
7.3.5 Pulverised coal grinding and firing systems
Direct and indirect firing systems
Direct firing
Semi-direct firing
Indirect firing
Semi-indirect firing
7.3.6 Coal system drying capacity
7.3.7 Coal firing system fans
7.3.8 Fine coal storage
7.3.9 Fine coal feeding and conveying
Volumetric feeders
Mass flow feeders
7.3.10 Pulverised coal conveying
7.4 Waste fuel handling
7.4.1 Waste gas fuel handling
7.4.2 Waste liquid fuel handling
Accompanying notes relating to figure 7.21
What is a safety case?
7.4.3 Solid waste and solid biomass fuel handling
Common types of solid waste used as fuel
Preparation of waste derived fuels
Sorting
Solid waste storage
Size reduction
Prepared fuel storage
Solid waste fuel feeding
Concluding remarks on waste derived fuels
References
7 . Applicable codes and standards
7 . Appendix 7A Safety case
Main features of a Safety Case
Contents of the Safety Case
Description of the Facility, including
Safety Information including
Safety Assessment
Emergency Plans
Emergency Incident Scenario Plans
Occupied Buildings Risk Assessment
8 - Furnace control and safety
8.1 Process control
8.1.1 Basic furnace control strategies
Control of product temperature
Fuzzy logic and rule based systems
8.2 Furnace instrumentation
8.2.1 Temperature measurement
8.2.2 Heat input measurement
Flow measurement of liquid and gaseous fuels
Calorific value measurement
Solid fuels
8.2.3 Determination of excess air
8.3 Flue gas analysis
8.3.1 Extractive gas sampling systems and analysers
Sample probe installation
Cold gas extractive systems
Hot wet gas extractive systems
Dilution extractive systems
8.3.2 In-situ systems
Dust monitors
Oxygen analysers
Cross duct analysers
Early CO/CO2 analysers
Folded beam analysers
Emissions monitoring using optical spectrometers
8.4 Combustion control
8.5 Ensuring furnace safety
8.5.1 Risk factors in furnace operation
8.5.2 Furnace start-up
Critical time for ignition during furnace start-up
8.5.3 Operation with insufficient combustion air
Corrective action for unintentional sub-stoichiometric operation
8.5.4 Flame quenching
8.5.5 Eliminating ignition sources
8.6 Burner management systems
8.6.1 Safety requirements for burner management systems
8.6.2 False trips
8.6.3 Achieving acceptable safety standards with programmable logic controller burner management systems
8.6.4 Choosing an appropriate safety integrity level
8.6.5 Determining the safety integrity level of the BMS system
8.6.6 Flame detectors
Nomenclature for Chapter 8
References
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9 - Furnace efficiency
9.1 Furnace performance charts
9.2 Mass and energy balances
9.2.1 On-site measurement
Flue gas sampling and analysis
Calibration and errors in plant instrumentation
9.2.2 Constructing mass and energy balances
Mass and energy balance for the furnace
9.3 Energy conversion
9.3.1 Low and high grade heat
9.3.2 Exergy and pinch point analysis
9.4 Heat recovery equipment
9.4.1 Recuperative heat exchangers
9.4.2 Regenerative heat exchangers
9.4.3 General heat exchanger design procedure
9.5 Identifying efficiency improvements
Nomenclature used in chapter
References
10 - Emissions and environmental impact
10.1 Formation of carbon monoxide
10.2 Formation of nitrogen oxides
10.2.1 Thermal NOx formation
10.2.2 Fuel NOx formation
10.2.3 Prompt NOx formation
10.2.4 NOx modelling
10.3 Formation of sulphur oxides
10.4 Formation of intermediate combustion products
10.4.1 Volatile organic compounds (VOCs)
10.4.2 Polycyclic aromatic hydrocarbons (PAH)
10.4.3 PCBs, dioxins and furans
10.5 Particulate emissions
10.5.1 Formation of soot
10.5.2 Formation and composition of fuel ash
10.5.3 Non-combustible volatile cycles
10.6 Environmental control of emissions
1.6.1 Prevention and abatement of emissions
Pre-flame control
In-flame control
End-of-pipe control
10.6.2 Dispersion modelling
Nomenclature used in chapter
References
11 - Furnace construction and materials
11.1 Basic performance requirements of the furnace structure
11.2 Basic construction methods
11.2.1 Brick lining
11.2.2 Monolithic linings
Castable refractory
Traditional installation of castable refractory
Installation of castable refractory by gunning
Drying and curing of cast and gunned refractory
Mouldable and rammable refractories
11.2.3 Furnace steelwork
11.2.4 Furnace roof construction
11.2.5 Furnace cooling systems
11.3 Practical engineering considerations in the use of refractories
11.4 Ceramic refractory materials
11.4.1 Testing of refractories
11.4.2 Properties and uses of refractories
Silica and siliceous refractories
Alumina and aluminous refractories
Chromite/magnesite/alumina refractories
Dolomite refractories
Zircon and zirconia refractories
Carbon refractories
Insulating refractories
11.5 Heat resisting and refractory metals
11.5.1 Effect of elevated temperature on metal properties
11.5.2 High temperature alloys
Service temperature
Intergranular corrosion
Proprietary high nickel alloys
11.6 Practical engineering considerations in the use of high temperature metals
11.7 Concluding remarks
References
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bksec2_11
11 . Appendix 11A Refractory materials
12 - Furnace design methods
12.1 Introduction
12.1.1 Design constraints
12.1.2 Cost of design changes
12.2 Conceptual design
12.2.1 Process functions
Straight through furnace system
Separation furnace system
Combining furnace with downstream separation
Combining and separation furnace system
12.2.2 Defining the physical and chemical changes
12.2.3 Preliminary mass and energy balances
12.2.4 Reliability of available process knowledge
Existing processes
New processes and pilot plants
12.2.5 Effect of upstream and downstream processes
12.2.6 Fuel choice
Fuel chemical compatibility with process
Heat transfer compatibility with the process
12.2.7 Potential for heat recovery and choice of equipment
Estimating the potential for heat recovery from hot product
Estimating the potential for heat recovery from hot flue gas
Estimating the potential for heat recovery from shell losses or cooling water
Economic considerations
12.3 Furnace sizing
aaa
Slab heating furnace design
Oil heating furnace design
Aggregate processing furnace
12.4 Burner Selection
12.5 Detailed analysis and validation of the furnace design
12.6 Furnace instrumentation and controls
Nomenclature for chapter 12
References
13 - Economic evaluation
13.1 Cost accounting
13.2 Distinction between capital and revenue
13.2.1 Fixed and variable costs
13.2.2 Capital costs
13.3 Profit and profitability
13.4 Financial ratios
13.5 Project costing
13.5.1 Order of magnitude costing
13.5.2 Study costing
13.6 Investment evaluation
13.7 Determining financial benefits
13.7.1 Base case costing
13.7.2 Case 1 costing – re-brick with no insulation
13.7.3 Case 2 costing – conversion to natural gas
13.7.4 Case 3 costing – conversion to natural gas with new calcium silicate lining
13.7.5 Case 4 costing – reinstate stack recuperators
13.7.6 Case 5 costing – conversion to blast furnace gas with stack recuperators
13.7.7 Case 6 costing – installation of self-recuperative burners
13.7.8 Case 7 costing – oxygen enrichment
13.7.9 Cost-benefit analysis
13.8 Post project analysis
References
14 - Selected examples of real furnace applications
14.1 Design of a new burner for a lime sludge kiln
14.1.1 The lime regeneration process
14.1.2 Design objectives for the multi-fuel burner
Fuel/air mixing
Coke particle residence time
High temperature zone close to the burner nozzle
14.1.3 Design methodology
Modelling
Mechanical design
Gas Nozzle
Coke transport and injection system
Primary air nozzle
14.1.4 Commissioning
14.2 Optimising flash furnace design
14.2.1 Site investigation
Methodology adopted
Sampling procedure
14.2.2 Physical modelling
14.2.3 Mathematical modelling
14.3 Contribution to the design of a new reforming process for fuel cell applications
14.3.1 Reformers for fuel cells
14.3.2 Burner design
14.3.3 Physical and mathematical modelling
Preliminary mathematical modelling
Physical modelling
Heat Flux modelling
14.3.4 Full size testing
14.3.5 Concluding remarks
14.4 Resolving tube internal coking and premature tube failure in a refinery heater
14.4.1 Diagnostic modelling
Mathematical modelling
Physical modelling
14.4.2 Correcting the poor air distribution
14.4.3 Burner modifications
14.5 Unsuccessful attempts to resolve severe problems with a preheater cement kiln
14.5.1 Cement manufacture by the dry process
Important considerations in kiln operation
14.5.2 Diagnosis of the problem
Determining secondary airflow
Physical modelling
Mathematical modelling
Summary of the problem
14.5.3 Attempted resolution of the problem
14.5.4 Concluding remarks
14.6 Investigation and elimination of coal firing system problems
14.6.1 A flawed and dangerous coal firing system
14.6.2 Reducing fuel consumption and increasing output by an upgrade of a poorly performing coal firing system
Implementation
Benefits achieved
14.7 Concluding remarks on implementation
References
15 - Future trends and concluding remarks
15.1 Trends in new materials
15.2 Trends in furnace emissions and fuels for furnaces
15.2.1 Opportunities and constraints for hydrogen
Opportunities for use as a fuel
Opportunities for use as a reductant
Constraints to widespread hydrogen utilisation
Cost
Water demand
Hydrogen transport
Safety
Concluding remarks on hydrogen
15.2.2 Opportunities and constraints for biomass based fuels
Concluding remarks on biomass based fuels
15.2.3 Opportunities and constraints for waste based fuels
Concluding remarks on waste based fuels
15.2.4 Prospects for alternative electrical energy as a power source
Concluding remarks on alternative electrical energy as a power source
15.3 Trends in carbon capture from furnaces
15.4 Trends in furnace controls
15.5 New applications for furnaces
15.6 Concluding remarks
References
Index
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
R
S
T
U
V
W
Y
Z
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