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Oxy-Fuel
for Ferrous and Non-Ferrous
Oxygen
Overview
Oxygen is a gas which is:
- Colorless
(liquid oxygen is pale blue)
- Odorless
- Necessary
to support life
- Necessary
for combustion
In Oxygen Enhanced
Combustion:
- Air is the
oxidant for most combustion processes
- Air contains
roughly four parts nitrogen and one part oxygen
- As the concentration
of oxygen increases:
- Flame temperature
increases
- Available
heat increases
- Heat transfer
rates increase
- Combustion
efficiency increases


There are three
main benefits to using Oxygen Enhanced Combustion: increased productivity, fuel
savings, and reduced emissions.
Increased
productivity
- Throughput
increase of 10% to 20% with low level enrichment.
- 25% to 40%
throughput increase with high level enrichment and 100% Oxy-fuel.
- Effective
in overcoming existing limitations: air supply / off gas handling system, equipment
/ burner capacity, sensible heat loss, and lower heat transfer rates.
Fuel
savings
- 15% to 70%
fuel savings depending on efficiency. Economics dependent on fuel cost, oxygen
cost, and efficiency gains.
- Sensible heat
is lost through the exhaust gases which contain mostly nitrogen.
- Oxygen enhanced
combustion reduces exhaust gas losses and increases heat transfer rates.
Reduced
emissions
- Oxy-fuel eliminates
the primary nitrogen source.
- Significant
reduction in exhaust gases which often lowers velocities and particulate carryover.
- Low NOx Oxy-fuel
burners using staged combustion.
- "Staged"
- Burners or systems that split one of the reactants (fuel or oxidant) into two
streams.
- The first
stream supports combustion under design conditions in the "primary zone".
- The second
stream is mixed with the products of the primary zone and the furnace gases to
complete combustion.
Oxy-Fuel
- No blower
air is used.
- Fuel is combusted
with ~100% oxygen.
- Higher flame
temperatures are ideal for melting applications.
- Good for low
efficiency processes because of available heat (Ladle Preheating).
- Good for applications
where high heat transfer rates are required (Rapidfire).
Applications
- Steel
Blast
Furnace Enrichment
In blast furnace enrichment, oxygen is injected to mix with supplemental
fuels to facilitate complete combustion and optimize heat release in the raceway.
Alternate injection methods further increase fuel efficiencies and permit higher
substitution rates. Fuel prices (natural gas, coal, coke) dictate economics and
substitution levels.
It offers several
benefits: less soot formation, improved heat release in the raceway, higher fuel
(PCI, Natural Gas) injection rates, and increased coke savings. Alternate injection
methods further improve coke savings (>$1MM/yr).
EAF
Oxy-Fuel Assisted Melting
EAF Oxy-Fuel Assisted Melting offers several benefits: increased production
(10-25%), reduced electrical power (30 to 80kWh/ton), electrode savings (10 to
15%), and lower unit production costs.
Oxy-Fuel
Ladle Preheating
Oxy-Fuel Ladle Preheating provides the following benefits: reduced molten
steel temperature loss (40% faster heat-up and hotter ladle bottoms), reduced
/ eliminated metal skulling on ladle lining, increased ladle refractory life (improved
temperature control and less spalling), 70% fuel savings, and 90% reduction of
exhaust gases.
Oxy-Fuel
Aluminum Rotary
Oxy-Fuel Aluminum Rotary provides the following benefits: increased production
(30 to 50%), reduced emissions (exhaust gases reduced 70 to 80%), lower fuel costs
(specific consumption reduced 50 to 60%), and net savings from $0.01 to $0.02/lb
(net annual savings $400,000 to $800,000).
Air-Oxy-Fuel
Aluminum Reverb
Air-Oxy-Fuel Aluminum Reverbs have several benefits: increased production
(20 to 35%), reduced emissions (exhaust gases reduced by ~60%), lower fuel costs
(30%), and net savings of $0.012/lb. of aluminum (net annual savings / benefit
$900,000).


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