Table of Contents
Introduction to Industrial Burners
What is an industrial burner?
- Basic of combustion is discussed in the previous post what are essential parts of gas burners.
- An industrial burner is a piece of mechanical equipment connected to a furnace or combustion chamber to assist the combustion process by correctly mixing air and fuel with designed velocity and using an ignition source
- Major parts of the burner
- air and fuel metering system
- ignition source
- Burner tiles
- air register: damper opening mechanism
- Fuel tips and pipe



- Wall-fired premix burner mounted on the fired heater wall is shown below
- High-pressure fuel is injected in the Centre of the venturi cone to entrain more air for combustion
- The mixture of air and fuel is ignited to form a flame. The following figure shows an example of venturi burner.
- The mounting of the gas-fired burner on the fired heater is shown below
Coal Fired Burner
- In power generation, most of the power is generated by coal-fired thermal power plant
- Coals are easily available at low cost in many countries
- The combustion process of a coal-fired boiler is more complex compared to gas-fired boiler due to turbulence, multiphase flow, ash handling, and pollution
- To understand such complex combustion and waste heat absorption, CFD modeling can be used to design and select the best configurations of burner and boiler furnace
- The pulverized coal-fired boiler is shown below. Burners can be wall-fired or corner-fired.
Schematic of Coal-fired Burner
- In a coal burner, coal particles are spread in the Centre of of burner surrounded by air
- Air staging carried out for low NOx
- The air-jet type low NOx burner of Babcock Wilcox is shown below. Air staging is carreid out to control combustion.
Cement Kiln Burner
- Cement kilns are used for the pyro-processing stage of the manufacture of Portland and other types of hydraulic cement, in which calcium carbonate reacts with silica-bearing minerals to form a mixture of calcium
- A burner is used to heat the cement mixture. Different types of burners have been used in cement industries
- Due to the high-temperature gradient across the cement kiln, thermal stress results in the failure of the shell of the cement kiln
- Major issues is the selection of low NOx burners and overheating of cement kiln
- CFD modeling will help to design a low NO burner and configuration of air cooling
- A typical Cement kiln Burner is shown below. It can be gas-fired or coal fired.
Oil burner
- Oil burners are also used in some cases when fuel gas is not available
- Oil burners need the mechanics of fuel automation for spreading liquid droplets, evaporation and mixing with air
- CFD modeling of the oil burner is presented in the previous post
Scope of CFD Simulation
- Objective: CFD simulation is carried out for industrial burners to understand the following results:
- Velocity contours
- Mixing Flow Pattern of fuel and air
- Flame Pattern
- NOx
- The following three industrial burners are considered for CFD modeling
- Premix (Inspiration Mix) burner
- Type pf fuel: Natural Gas
- Firing rate: 0.3 MM Btu/hr
- A simple heater model considered to check burner design
- Coal-Fired Burners in Boiler
- Type pf fuel: Coal
- Firing rate: 800 MW
- waste recovery units like super heater, economizers,s and air pre-heater
- Cement Kiln burners :
- Type pf fuel: Natural Gas
- Firing rate: 3.7 MM Btu/hr
- Air jets used for cooling of heated cement kiln
- Premix (Inspiration Mix) burner
- Pre-mix burners have been mounted vertically in the fired heater
- The maximum capacity of the Venturi burner is up to 2 MM Btu/hr
- We have to select the best suitable burner configuration based on CFD results
CFD Modelings of Premix Venturi Burner
Computational Domain
- The computational domain is created in ANSYS space claim
- Hight of the furnace is sufficiently taken high
Geometry of Burner
- The computational domain for the Venturi- type burner is shown below
- The opening of the air inlet is fixed for the present simulation
- The 3D model was created in ANSYS space claim
- The details of combustion modeling is discussed in the previous post
- Details of the Burner are shown below
- To retain the stability of the flame, a large number of mixture holes are created at the outlet of the mixing tube. The size of the hole is 0.2 inches. These holes plays the role of flame arrester.
- The mass flux across each hole should not exceed 6 lb/ft2-s for stable flame
Boundary Conditions for Premix Burner
- Fuel Firing Rate: 0.25 MM Btu/hr
- Type of Fuel : Natural Gas
- Burner Air Inlet
- The mass flow rate of air: 230 lbm/hr
- Inlet temperature: 90 °F
- Burner Fuel Air inlet
- A mass flow rate of air: 11.7 lbm/hr
- Inlet temperature: 80 °F
- Ambient Condition
- Air inlet temperature: 80° F
CFD Results
Velocity Contours
- High-velocity fuel induct the surrounding air via the venturi effect. It does need external means to supply air.
- Inducted air and fuel are mixed in the mixing chamber. After that its velocity decreases.
Temperature contours
CFD Modelings of Coal-Fired Burners in Boiler
Computational Domain
CFD Results for Coal-Fired Boiler
CFD Modeling of Cement kiln with Burner