Environmentally Oriented Modernization of Power Boilers

Cover
Environmentally Oriented
Modernization of Power Boilers
Copyright
Dedication
Chapter 1 - Introduction
	References
Chapter 2 - Boiler efficiency and thermal losses
	References
Chapter 3 - Modernization to reduce the flue gas loss
	3.1 - Lowering of flue gas temperature
		3.1.1 - Modernization of pressure convective surfaces
			3.1.1.1 - Plain tube heat exchangers with in-line and staggered arrangement
			3.1.1.2 - Staggered and in-line banks of longitudinally finned tubes
			3.1.1.3 - Staggered and in-line tube banks with transverse ribs
				Flag-type surfaces of the evaporator
		3.1.2 - Modernization of air heaters increasing the heat transfer
			3.1.2.1 - Types of air heaters
			3.1.2.2 - Modernization of rotary air heaters
			3.1.2.3 - Modernization of recuperative air heaters by intensifying the heat transfer inside the tubes
			3.1.2.4 - Replacing the existing air heater with the heat pipe air heater
		3.1.3 - Application of a system (or modification of an existing one) for cleaning of heated surfaces from ash deposits
			3.1.3.1 - Jet blowers
			3.1.3.2 - Acoustic cleaners
			3.1.3.3 - Shot cleaning systems
			3.1.3.4 - Rapping devices
			3.1.3.5 - Choice of cleaning concept
		3.1.4 - The influence of fouling on the operation of rotary air heaters
		3.1.5 - Implementation of an additional heat exchanger
		3.1.6 - Lowering of feedwater temperature in the air heater
	3.2 - Selection of the minimum flue gas temperature at the boiler outlet
		3.2.1 - Dew point of the flue gas
		3.2.2 - Methods for determining the acid dew point
		3.2.3 - Dew point measurements in boilers
		3.2.4 - Influence of the tubular air heater structure on the permissible outlet temperature of the boiler
		3.2.5 - The range of reduction of flue gas outlet temperature in regenerative rotary air heaters
		3.2.6 - Heat pipe air heater
		3.2.7 - Preheating the air at the boiler inlet
	3.3 - Optimization of flue gas outlet temperature
		3.3.1 - Objective function
		3.3.2 - Change in boiler efficiency as a function of load
		3.3.3 - Block flow diagram of the flue gas outlet temperature selection
		3.3.4 - Exhaust gas temperature distribution in the section from the boiler to the chimney outlet
			3.3.4.1 - Temperature distribution in precipitators of boilers
				Electrostatic precipitator
				Fabric filter
			3.3.4.2 - Induced draft fans
			3.3.4.3 - The impact of FGD on temperature distribution – waste heat recovery systems
			3.3.4.4 - Stack
	3.4 - Lowering the air excess number in the boiler
		3.4.1 - Reducing the ingress of the false air to the combustion chamber and convection section
		3.4.2 - Reduction of leakages in air heaters
		3.4.3 - Lowering of air excess number in the furnace
	References
Chapter 4 - Reduction of nitrogen oxide emissions
	4.1 - Formation of nitrogen oxides
		4.1.1 - Oxidation of fuel nitrogen
		4.1.2 - Formation of thermal NO
		4.1.3 - Formation of prompt NO
		4.1.4 - Formation of N2O
		4.1.5 - Oxidation of NO
	4.2 - Impact of operating conditions of the furnace on emissions of nitrogen oxides
	4.3 - Methods of reduction of nitrogen oxide emissions in PF boilers
		4.3.1 - Primary and secondary methods of NOx reduction
		4.3.2 - Air staging
		4.3.3 - Staging of air and fuel
			4.3.3.1 - Reburning
			4.3.3.2 - Staging of air and fuel in systems with various concentration of fuel and air mixture
			4.3.3.3 - Low NOx burners
		4.3.4 - Powered OFA
			4.3.4.1 - ROFA system
			4.3.4.2 - SJBS – Special Jet Boiler System
		4.3.5 - Flue gas recirculation
	4.4 - Secondary methods of NOx reduction
		4.4.1 - Selective catalytic reduction SCR
			4.4.1.1 - General description
			4.4.1.2 - Efficiency of the catalyst
			4.4.1.3 - Types of SCR installations
			4.4.1.4 - Design and operational considerations for introducing the high-dust SCR in existing boilers
			4.4.1.5 - RAH SCR
		4.4.2 - Selective non-catalytic reduction SNCR
			4.4.2.1 - General description
			4.4.2.2 - Industrial applications
			4.4.2.3 - Ways to improve SNCR efficiency
			4.4.2.4 - Dry SNCR
			4.4.2.5 - Rich Reagent Injection
			4.4.2.6 - Selective Auto Catalytic Reduction (SACR)
	4.5 - NOx reduction methods without the use of ammonia or urea
		4.5.1.1 - Oxidation of NO to NOy and its removal in FGD
		4.5.1.2 - SCONOX technology
		4.5.1.3 - SCR of NOx by hydrocarbons (HC-SCR)
		4.5.1.4 - NOx Tempering
	4.6 - Combined methods of NOx control
	4.7 - The future of NOx emission reduction methods
	References
Chapter 5 - Modernization of fuel grinding systems
	5.1 - Quality of pulverized coal
		5.1.1 - Coal particle size distribution
		5.1.2 - Grindability of fuels
		5.1.3 - Optimum quality of coal in pulverized-fuel boilers
	5.2 - Coal mills
	5.3 - Modernizations of coal mills arising from low-NOx combustion
		5.3.1 - Improvement of pulverized coal quality
		5.3.2 - Increasing the capacity of the milling device
		5.3.3 - Modernization to eliminate dust settling in pipelines
		5.3.4 - Modernization of mills to differentiate the concentration of pulverized fuel in burners
		5.3.5 - Modernization improving the dust distribution
	5.4 - Modernization to improve the operating conditions of pulverizers in dynamic states
		5.4.1 - Replacement of existing mills
		5.4.2 - Classifier as an active control element
		5.4.3 - Increased or decreased ventilation of the mills
		5.4.4 - Increasing the pressure of grinding elements
	5.5 - Modernization of pulverizers to reduce harmful emissions
	References
Chapter 6 - Replacing coal with other fuels
	6.1 - Introduction
	6.2 - Replacement of coal with natural gas
	6.3 - Replacement of coal with blast furnace gas and low-quality syngas
	6.4 - Replacement of coal with fuel oil
	6.5 - Replacement of hard coal with lignite
	6.6 - Modernization for the combustion of various fuels in the same boiler
	References
Chapter 7 - Adaptation of boilers for biomass burning
	7.1 - Types of biomass used in the power industry
	7.2 - Adaptation of PF boilers for biomass burning
		7.2.1 - Combustion of biomass in a separate pre-combustor
		7.2.2 - Integration of co-combustion grate for biomass into the bottom of PF boiler furnace
		7.2.3 - Grinding and pneumatic transport of biomass to the boiler
		7.2.4 - Gasification of biomass and combustion of the product gas as additional fuel
		7.2.5 - Combustion of the suspension of fine biomass particles in water or oil
		7.2.6 - Systems based on parallel connection on the steam side of the PF boiler and a biomass boiler
		7.2.7 - General remarks
	7.3 - Complete replacement of coal with biomass
		7.3.1 - Replacement of coal with biomass in PF boilers
		7.3.2 - Revamping of the PF boiler with a fluidized bed boiler
		7.3.3 - Replacement of coal with biomass in grate boilers
	7.4 - Adaptation of boilers for wastes burning
	References
Chapter 8 - Harmful phenomena in modernized boilers
	8.1 - Hot corrosion on the flue gas side
		8.1.1 - High-temperature sulfur-induced corrosion
		8.1.2 - High-temperature chlorine-induced corrosion
			8.1.2.1 - Thermodynamic stability of oxides and chlorides
			8.1.2.2 - Corrosion in the presence of gaseous chlorine compounds
			8.1.2.3 - Corrosion due to reactions in solid phase assisted by chlorine compounds
		8.1.3 - Corrosion of waterwalls in boiler furnaces
		8.1.4 - Methods to prevent the low-NOx corrosion
			8.1.4.1 - Modification of the atmosphere in the furnace
			8.1.4.2 - Modification of combustion conditions
			8.1.4.3 - Boiler furnace atmosphere monitoring
			8.1.4.4 - Anticorrosion coatings
				Hybrid coatings
				Plasma coatings
				Supersonic gas-flame spraying (High Velocity Oxygen Fuel HVOF)
				Weld cladding
				Electrolytically applied coatings
			8.1.4.5 - Evaluation of methods to prevent the low-NOx corrosion
		8.1.5 - Corrosion of superheaters
		8.1.6 - Methods to prevent the corrosion of superheaters
			8.1.6.1 - Additives
				Aluminosilicates
				Sulfur and its compounds
				Protective coatings
				Selection of tube material
				Design of the superheater
	8.2 - LT corrosion on the flue gas side
	8.3 - Threats to boiler reliability resulting from harmful phenomena on the water side
	8.4 - Fly-ash erosion
		8.4.1 - General description
		8.4.2 - Operational modifications to reduce the erosion of convection surfaces of the boiler
		8.4.3 - Modernizations increasing resistance to erosion
		8.4.4 - Erosion of SCR catalysts
	8.5 - Fouling
		8.5.1 - Types and properties of ash deposits
		8.5.2 - Formation of high temperature (HT) ash deposits
		8.5.3 - Formation of medium temperature (MT) ash deposits
		8.5.4 - Indices that determine the tendency of fuels to form deposits on convection surfaces
	8.6 - Slagging
		8.6.1 - The mechanism of the process
		8.6.2 - The influence of fuel properties
		8.6.3 - The influence of physical parameters of the process
		8.6.4 - Slagging indices
	8.7 - Deposition of ammonium salts
	References
Chapter 9 - Conversion of an existing boiler to a condensing boiler
	9.1 - Condensing technology
	9.2 - Industrial applications
	References
Chapter 10 - Increasing flexibility of boiler operation
	10.1 - Adaptation of the boiler to work with a load higher than nominal
		10.1.1 - Evaporators in natural circulation boilers
		10.1.2 - Superheaters
		10.1.3 - Mills and furnaces
		10.1.4 - Convection surfaces
	10.2 - Lowering the minimum boiler load
		10.2.1 - Combustion stability
		10.2.2 - Steam temperatures
		10.2.3 - Preventing dew condensation
	10.3 - Frequent start-ups and large and rapid load changes
	10.4 - Increasing flexibility of boiler pressure parts
		10.4.1 - Damage mechanisms due to cyclical operation in high temperature
		10.4.2 - The influence of the design and course of operation on the expected lifetime of boiler components
	10.5 - Production flexibility
	References
Chapter 11 - Interactions between emission reduction systems
	11.1 - Introduction
	11.2 - Interactions between NOx reduction systems and particulate control devices
		11.2.1 - Interactions with ESPs
			11.2.1.1 - Influence of primary NOx reduction methods on ESP efficiency
			11.2.1.2 - Influence of secondary NOx reduction methods on ESP efficiency
		11.2.2 - Interactions with fabric filters
			11.2.2.1 - Influence of primary NOx reduction methods on FF efficiency
			11.2.2.2 - Influence of secondary NOx reduction methods on FF efficiency
	11.3 - Interactions between SOx reduction systems and particulate control devices
		11.3.1 - Influence of flue gas desulfurization on ESP efficiency
		11.3.2 - Influence of flue gas desulfurization on FF efficiency
	11.4 - Influence of particulate control devices and NOx reduction systems on wet FGD
		11.4.1 - The impact of particulate control on wet FGD
		11.4.2 - Influence of primary NOx reduction methods on wet FGD
		11.4.3 - Influence of SCR and SNCR on wet FGD
	References
12 Symbols
Index
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