Air Permitting

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Air Permitting
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Permitting

• Trust - DNR/EPA/Facility
• PSD/NSR has been fought over in courts since
  inception- no one really understands it.
• You have to know all the answers before you
  begin.
• De-bottlenecking is always an issue
• Circumvention (Subdividing projects) can be
  issue.
• It is difficult to prove a negative.
• Delays For example - 2 1/2 years

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Environmental effects of Fuel Switch- Coke to NG

• Should reduce CO2 emissions
• ?H combustion (carbon) - 394kj Cs O2
  CO2
• ?H combustion (hydrogen) - 242kj H2 1/2
  O2 H2O
• ?Hcombustion (methane) - 891kj CH4 2O2
  CO2 2H2O
• 50 of heat comes from combustion of hydrogen.
• But must also consider Endothermic rxns
• C H2O CO H2
• CO2 C 2CO
• Should reduce SO2 NOX emissions.
• Oxygen use (stoichoimetric) reduces volume of
  combustion gases to be cleaned by APCD 79 and
  increases flame temp ( 3,550 - 5,000ºF).

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Permitting issues

• Oxyfuel injection - Not exempt under
  NR406.04(4,i). External furnace lt 25 mmBTU/hr lt
  128mmBTU/hr.
• Potential to increase melt rate as well as reduce
  coke use.
• Purpose of NSR/PSD
• Subject BACT to facilities with increasing
  emissions.
• What about cleaner processes?
• Permitting costs (70,000 staff hours)

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Dehumidification Vaporization Recovery

• Facilities desire to dehumidify cupola blast air.
  Cupola fuel, coke, is at record prices.
  Removing one pound of water vapor from the blast
  air eliminates 1.19 pounds of coke from the
  cupola. Dehumidifying blast air for one cupola
  could save 491 tons of coke per year (and the
  associated greenhouse gas emissions).
• A dehumidification unit for this facility would
  ordinarily consume 84 tons of refrigeration, to
  condense water vapor from the air stream and 6
  therms of NG to dry desiccant.
• The current oxygen consumption rate is about 77.4
  lb./min.
• The heat required to vaporize and warm oxygen
  from its liquid state, -297 degrees Fahrenheit at
  1 atm, to a gaseous state at 70 degrees
  Fahrenheit is about 850,000 BTU/hr.
• 85 of this refrigeration could be supplied by
  recovery of existing oxygen vaporization.
• If oxy-fuel burners are employed oxygen
  vaporization could supply all necessary
  refrigeration to a dehumidification system.
• In summary
• An Air dehumidification unit is estimated to cost
  about 75,000.
• Additional costs (heat exchanger, piping, fluids
  and pump)remain to be determined.
• A yearly coke saving of 121,611 has been
  estimated.
• Blast dehumidification could be cost advantageous
  especially if refrigeration energy can be
  recovered.

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Three ideas

• Fuel Switching
• Combustion Air Dehumidification
• Recover Refrigeration from LOX/LN vaporizers

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Ways to Help

• Facilitate Permitting
• RD Basis?
• Fast tracking for energy efficient, clean,
  projects?
• Engineering Help
• Small oxyfuel burners (able to fit within
  existing cupola tuyeres)
• Heat exchanger design/CGA code
• Grant Money