Industrial and Process Furnaces
Principles, Design and Operation
by Peter Mullinger and Barrie Jenkins
Chapter 1 – Introduction
- What is a furnace?
- Furnace outline
- Furnace classification
- Principle objectives of furnace designers and operators
- Where are furnaces used? Brief review of current furnace applications and technology
- Ceramics, brick making and pottery
- Cement and lime
- Glass making
- Metal ore smelting
- Metal refining
- Flash and fluid bed furnaces
- Metal physical processing
- Incinerators and resource recovery furnaces
- Furnaces with reducing atmospheres
- Oil refining and petrochemical furnaces
- Drivers for improved efficiency
- Concluding remarks
Chapter 2 – The combustion process
- Simple combustion chemistry
- The complete oxidation of carbon
- The complete oxidation of hydrogen
- The incomplete oxidation of carbon
- The oxidation of carbon monoxide
- Combustion calculations
- Chemical reaction kinetics
- Types of reactions
- Reaction rate theory
- Reaction rate behaviour
- Burning droplets and particles
- The physics of combustion
- The role of primary air
- The role of swirl flows
- Turbulence in jets
- Secondary flow aerodynamics
- Effect of excess air on fuel consumption
- Multiple burner installations
Chapter 3 – Fuels for furnaces
- Gaseous fuels
- Properties of natural gas
- Manufactured gas
- Wobbe number or index
- Flammability limits
- Calculation of the flammable limits for mixtures of gases
- Influence of temperature and pressure on the limits
- Flame radiation from gaseous fuels
- Liquid fuels
- Solid fuels
- Ash
- Waste fuels
- Choice of fuel
- 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
- Safety
- Emissions
- Solid fuel bibliography
- Furnace performance
Chapter 4 – An introduction to heat transfer in furnaces
- Conduction
- Steady state conduction
- Transient conduction
- Analytical approach
- Numerical approach
- Convection
- Dimensional analysis
- Application to convective heat transfer
- Evaluating convective heat transfer coefficients
- High temperature convective heat transfer
- Radiation
- Physical basics of radiative exchange
- Emissivity and absorptivity
- View factors
- Equivalent grey surface
- Mean beam length
- Electrical heating
- Resistance heating
- Direct resistance heating
- Indirect resistance heating
- Arc heating
- Electrode devices
- Electrodeless devices
- Induction heating
- Dielectric heating
- Infrared heating
- Resistance heating
- Appendix 4A Tables of emissivity data
Chapter 5 – Flames and burners for furnaces
- Types of flame
- Premixed flames
- Turbulent jet diffusion flames
- Heterogeneous combustion
- Atomisation of liquid fuels and pulverisation of coal
- The importance of drop and particle size
- Function of a burner and basics of burner design
- The essential importance of heat flux profiles
- Flame stabilisation
- Gas burners
- 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
- Turbulent jet diffusion burners
- Precessing jet diffusion burners
- Oil burners
- Turndown
- Atomisers
- Pressure jet atomisers
- Twin fluid atomisers
- Pulverised coal burners
- Furnace aerodynamics
- Burner and furnace air flow patterns
- Single burner systems
- Package burner installations
- Rotary kilns and driers, etc.
- Multiple burner systems
- Combustion air duct design
- Common windbox and plenum design
- Combustion system scaling
- Example of combustion system scaling
- Single burner systems
- Furnace noise
- Combustion roar
- Nozzle and turbulent jet noise
- Fan noise
- Pipe and valve noise
- Furnace noise attenuation
- Combustion driven oscillations
- Premixed burners
Chapter 6 – Combustion and heat transfer modelling
- Physical modelling
- Thring-Newby parameter
- Craya-Curtet parameter
- Becker throttle factor
- Curtet number
- Relationship between scaling parameters
- Determining the required model flows
- Applying the scaling parameter
- Applying a post-measurement correction
- Mathematical modelling
- Simple well-stirred furnace models
- Long furnace models
- Two- and three-dimensional zone models
- Computational fluid dynamics models
- Gridding of CFD models
- Convergence of CFD models
- Particle drag in combustion systems
- Application of modelling to furnace design
Chapter 7 – Fuel handling systems
- Gas valve trains
- Safety shutoff systems
- Double block and bleed
- Leak testing and proving
- Fuel oil handling systems
- Storage, pumping and heating
- Oil valve trains
- Pulverised coal handling and firing systems
- Raw coal bunkers and feeders
- Coal grinding and drying
- Coal drying characteristics
- Coal mills
- Ball mills
- Vertical spindle mills
- High speed mills
- Coal mill grinding capacity
- Coal fineness
- Coal dryness
- Pulverised coal grinding and firing systems
- Direct and indirect firing systems
- Direct firing
- Semi-direct firing
- Indirect firing
- Semi-indirect firing
- Coal system drying capacity
- Coal firing system fans
- Fine coal storage
- Fine coal feeding and conveying
- Volumetric feeders
- Mass flow feeders
- Pulverised coal conveying
- Waste fuel handling
- Waste gas fuel handling
- Waste liquid fuel handling
- Solids waste fuel handling
- Size distribution
- Environmental benefits and health hazards of waste fuel utilisation
- Applicable codes and standards
- Safety shutoff systems
Chapter – 8 Furnace control and safety
- Process control
- Basic furnace control strategies
- Control of product temperature
- Fuzzy logic and rule-based systems
- Furnace instrumentation
- Temperature measurement
- Heat input measurement
- Flow measurement of liquid and gaseous fuels
- Calorific value measurement
- Solid fuels
- Determination of excess air
- Flue gas analysis
- Extractive gas sampling systems and analysers
- Sample probe installation
- Cold gas extractive systems
- Hot wet gas extractive systems
- Dilution extractive systems
- In-situ systems
- Dust monitors
- Oxygen analysers
- Cross-duct analysers
- Combustion control
- Ensuring furnace safety
- Risk factors in furnace operation
- Furnace start-up
- Critical time for ignition during furnace start-up
- Operation with insufficient combustion air
- Corrective action for unintentional sub-stoichiometric operation
- Flame quenching
- Eliminating ignition sources
- Burner management systems
- Safety requirements for burner management systems
- False trips
- Achieving acceptable safety standards with programmable logic controller burner management systems
- Choosing an appropriate safety integrity level
- Determining the safety integrity level of the BMS system
- Flame detectors
- Extractive gas sampling systems and analysers
- Basic furnace control strategies
Chapter 9 – Furnace efficiency
- Furnace performance charts
- Mass and energy balances
- On-site measurement
- Flue gas sampling and analysis
- Calibration and errors in plant instrumentation
- Constructing mass and energy balances
- On-site measurement
- Energy conversion
- Low and high grade heat
- Exergy and pinch point analysis
- Heat recovery equipment
- Recuperative heat exchangers
- Regenerative heat exchangers
- General heat exchanger design procedure
- Identifying efficiency improvements
Chapter 10 – Emissions and environmental impact
- Formation of carbon monoxide
- Formation of nitrogen oxides
- Thermal NOx formation
- Fuel NOx formation
- Prompt NOx formation
- NOx modelling
- Formation of sulphur oxides
- Formation of intermediate combustion products
- Volatile organic compounds (VOCs)
- Polycyclic aromatic hydrocarbons (PAH)
- PCBs, dioxins and furans
- Particulate emissions
- Formation of soot
- Formation and composition of fuel ash
- Non-combustible volatile cycles
- Environmental control of emissions
- Prevention and abatement of emissions
- Pre-flame control
- In-flame control
- End-of-pipe control
- Dispersion modelling
- Prevention and abatement of emissions
Chapter 11 – Furnace construction and materials
- Basic performance requirements of the furnace structure
- Basic construction methods
- Brick lining
- 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
- Furnace steelwork
- Furnace roof construction
- Furnace cooling systems
- Practical engineering considerations in the use of refractories
- Ceramic refractory materials
- Testing of refractories
- 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
- Heat resisting and refractory metals
- Effect of elevated temperature on metal properties
- High temperature alloys
- Service temperature
- Intergranular corrosion
- Proprietary high nickel alloys
- Practical engineering considerations in the use of high temperature metals
- Concluding remarks
- Selection of relevant standards
- Appendix 11A General properties of selected refractory materials
Chapter 12 – Furnace design methods
- Introduction
- Design constraints
- Cost of design changes
- Conceptual design
- Process functions
- Straight-through furnace system
- Separation furnace system
- Combining furnace with downstream separation
- Combining and separation furnace system
- Defining the physical and chemical changes
- Preliminary mass and energy balances
- Reliability of available process knowledge
- Existing processes
- New processes and pilot plants
- Effect of upstream and downstream processes
- Fuel choice
- Fuel chemical compatibility with the process
- Heat transfer compatibility with the process
- 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
- Furnace sizing
- Slab heating furnace design
- Oil heating furnace design
- Aggregate processing furnace
- Burner selection
- Detailed analysis and validation of the furnace design
- Furnace instrumentation and controls
- Process functions