Article

Selection Criteria for Furnace Burners

When selecting the ideal burner for your application it is necessary to take into account the design characteristics of the application.

NUTEC Bickley

11/18/2019

3 minutes

11/18/2019

3 minutes

Selecting the Ideal Burner

When selecting the ideal burner for your application it is necessary to take into account the design characteristics of the application, the performance criteria and the following considerations:

  • Do not sacrifice uniformity by optimizing just a few burners.
  • Select and define better burner position, ensuring full understanding of the application and all its requirements.
  • Precisely determine and calculate the thermal capacity that the heating process really demands.
  • A standard cubic foot of air will always release 100Btu, regardless of the fuel used.

The points we must review in order to choose the correct burner are as follows:

  • Application, or process to perform
  • Fuel(s) available
  • Possible design limitations
  • Control method
  • Furnace/oven casing considerations
  • Process considerations
  • Number of burners to be used
  • Where they will be located
  • Capacity required to do the job

In this article we will talk about the different types of burners, their characteristics, design principles and existing models.

High Velocity Burners

These burners have the following characteristics:

  • Convection heating
  • Approximate 340mph (150m/s) velocity
  • Excess air capacity >3000%
  • High operating range
  • Suitable for preheated air up to 900°F (480°C)

Design Principles

  • High velocity
  • Wide operating capabilities
  • Stoichiometric and excess fuel combustion
  • Adjustable air/fuel ratio
  • High excess air ratio, with excellent flame stability
  • Direct spark ignited; protected from heat
  • Originally designed for firing brick tunnel kilns with constant high air flow

Construction Principles

  • Heat resistant cast iron body
  • Integrated air/gas holes
  • Gasket for special burner mounting body
  • Cast iron assembly: contains air/fuel access, and flame stabilizer
  • 70% alumina precast block, with good resistance to thermal shock; plus a lightweight mullite high alumina block option

Nozzle Types

H – High Velocity
R – Round Nozzle

  • Ideal for fiber or refractory brick walls
  • Temperatures up to 2800°F (1540°C)
  • Preheated air up to 900°F (480°C)

H – High Velocity
S – Rectangular Nozzle

  • Ideal for refractory brick walls
  • Ideal replacement for older burners
  • Temperatures up to 2800°F (1540°C)
  • Preheated air up to 900°F (480°C)

H – High Velocity
C – Ceramic Nozzle

  • Compact and lightweight silicon carbide
  • Ideal for fiber wall replacements
  • Temperatures up to 2500°F (1370°C)
  • Preheated air up to 900°F (480°C)

H – High Velocity
A – Alloy Nozzle

  • Compact and lightweight silicon carbide
  • Ideal for fiber wall furnaces using ambient air
  • Temperatures up to 1900°F (1040°C)

Forward Flame Burners

These burners have the following characteristics:

  • Radiation heating
  • Approximate velocity of 60mph (27m/s)
  • Limited excess air capacity
  • Process temperatures up to 2800°F (1540°C)
  • Dual fuel (gas/oil) models
  • Suitable for preheated air up to 900°C

Design principles

  • Sealed as opposed to open style entries, for proper airflow control
  • Nozzle mix as opposed to pre-mix, to increase operating limits
  • Excess air capacity to improve furnace temperature uniformity
  • Large gas pipes offering the ability to use a variety of fuels (including low calorific fuels)
  • It’s easy to adapt oil atomizer for conversion to dual fuel version
  • Conventional type of forward pattern flame burner

Capacities

  • Available in nine sizes and capacities (0.19MMBtu/h to 4.35MMBtu/h)
  • The burner capacity is determined by the air flow capacity at 16 psig pressure
  • Each burner capacity corresponds to a specific size of the air inlet pipe

Flat Flame Burners

These burners have the following characteristics:

  • Radiation heating
  • No forward velocity
  • Flame size ratio of 1/0.1 (length/diameter)
  • Process temperatures up to 2800°F (1540°C)
  • Suitable for preheated air up to 900+°F (480+°C)

Design principles

  • The shape of the block, combined with the swirl of combustion air, results in the flat flame
  • The combustion gases are directed radially, evenly heating the adjacent furnace refractory wall
  • The radiant heat of the burner block and the adjacent refractory is transmitted evenly to the load
  • The space between the burner block and the load can be reduced for efficient heat transfer without generating hot spots, since the flame has no forward speed
  • Wide variety of blocks and assemblies available
  • Suitable for both ambient temperature and preheated combustion air

Capacities

  • High excess air capacity to improve temperature uniformity
  • Heat resistant components suitable for preheated air at temperatures of 750°F (400°C)

Radiant Cone Burners

These burners have the following characteristics:

  • Radiation heat transfer, with localized flame
  • Compact, short flame
  • Process temperatures up to 2800°F (1540°C)
  • Suitable for preheated air up to 900+°F (480+°C)

Ultra-Low Emission Burners

These burners are ideal for combustion air staging.

At NUTEC Bickley we work hand in hand with the Fives North American brand and its LNI (Low NOx Injection) technology.

Radiant Tube Burners

These burners have the following characteristics:

  • Ideal for applications requiring indirect firing
  • Radiation heat transfer
  • Long flame burner design, for uniform tube heating
  • Available with plug-type heat recuperator

Burner Dimensions

  • Maximum capacity of 40MMBtu/h
  • Fuel: Natural Gas @ 1034Btu/ft3 (9208Kcal/m3)
  • Turndown (max cap:min cap) = 8:1
  • Burner operating pressure 1–16 osi

At NUTEC Bickley we are experts in the design of safe equipment using the latest combustion technology. Get in touch with our advisors to help you operate more safely.

Want to Know More?

At NUTEC Bickley, we are committed to providing you with valuable content that helps you make informed decisions for your business. Thank you for taking the time to read this entry and we hope it provided you with insights that you can apply to your operations.

If you have any questions or would like to learn more about our products and services, please don’t hesitate to contact us.

To get in touch, simply fill out the form, and one of our experts will get back to you as soon as possible.

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