Flame Interaction and Rollover Solutions in Ethylene Cracking - - PowerPoint PPT Presentation

Flame Interaction and Rollover Solutions in Ethylene Cracking Furnaces

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EEPC Ethylene Seminar 24-26 October 2012, Barcelona (Spain)

EEPC Ethylene Seminar 24-26 October 2012, Barcelona

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Statement of Problem

• Cracking furnace must

be retrofitted with new hearth burners to meet lower NOX requirements (150 mg/Nm3)

• Tight burner spacing
• Flame rollover is not

acceptable

EEPC Ethylene Seminar 24-26 October 2012, Barcelona

Application Description

• 2 Furnaces, 24 floor

burners each, double fired

• RFG ~10% H2 by volume
• Average firebox

temperature: 1250°C

• Firebox dimensions:

10.21 x 2.8 x 9.93 m

• Induced draft

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EEPC Ethylene Seminar 24-26 October 2012, Barcelona

Technology Employed

• Zeeco “Enhanced-

Jet” Ultra Low NOX Burner

• Secondary tips

inspirate inert flue gas into flame

• Capable of sub 100

mg/NM3 NOX emissions

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EEPC Ethylene Seminar 24-26 October 2012, Barcelona

Reducing NOx

Thermal NOX is the primary contributor to total NOX.

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2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 Normalized Thermal NOx Production Adiabatic Flame Temperature (°F)

Thermal NOx vs Adiabatic Flame Temperature

EEPC Ethylene Seminar 24-26 October 2012, Barcelona

Burner Design

• Secondary tips

fire into flue gas, inspirating flue gas into the flame

• Primary gas

tips provide “fuel staging” and allow for tuning of heat flux profile

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EEPC Ethylene Seminar 24-26 October 2012, Barcelona

No Flame Rollover

• Inherent furnace currents

tend to pull gasses towards tubes around 4 m above floor

• Fuel gas never crosses air

stream so fuel gas is always between air and wall and cannot roll over

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EEPC Ethylene Seminar 24-26 October 2012, Barcelona

Heat Flux Profile

Heat flux profile can be “tuned”

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EEPC Ethylene Seminar 24-26 October 2012, Barcelona

Enhanced Jet Data

• 39 PPMV (79

mg/NM3) NOX

• Corrected to 3%

O2

• 1275°C Firebox
• 1065°C Floor

Temp.

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EEPC Ethylene Seminar 24-26 October 2012, Barcelona

Enhanced Jet Video

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