ACT - NOx Emissions from Iron Steel Mills ALTERNATIVE CONTROL TECHNIQUES DOCUMENT --NOx EMISSIONS FROM IRON AND STEEL MILLS Emission Standards Division U.S. ENVIRONMENTAL PROTECTION

EPA-453/R-94-065

ALTERNATIVE CONTROLTECHNIQUES DOCUMENT --

NO EMISSIONS FROM IRON AND STEEL MILLSx

Emission Standards Division

U.S. ENVIRONMENTAL PROTECTION AGENCYOffice of Air and Radiation

Office of Air Quality Planning and Standards

Research Triangle Park, North Carolina 27711September 1994

ALTERNATIVE CONTROL TECHNIQUES DOCUMENTS

This report is issued by the Emission Standards Division,

Office of Air Quality Planning and Standards, U. S. Environmental

Protection Agency, to provide information to State and local air

pollution control agencies. Mention of trade names and

commercial products is not intended to constitute endorsement or

recommendation for use. Copies of this report are available --

assupplies last-- from the Library Services Office (MD-35), U. S.

Environmental Protection Agency, Research Triangle Park, North

Carolina 27711 ([919] 541-5514) or, for a nominal fee, from the

National Technical Information Service, 5285 Port Royal Road,

Springfield, VA 22161 ([800] 553-NTIS).

i

TABLE OF CONTENTS

Chapter Page

LIST OF FIGURES . . . . . . . . . . . . . . . . . ivLIST OF TABLES . . . . . . . . . . . . . . . . . v

1 INTRODUCTION . . . . . . . . . . . . . . . . . . 1-1

2 SUMMARY . . . . . . . . . . . . . . . . . . . . . 2-12.1 SOURCES OF NO EMISSIONS . . . . . . . . . . 2-1X2.2 UNCONTROLLED NO EMISSIONS . . . . . . . . . 2-3X2.3 NO EMISSIONS REDUCTION TECHNIQUES . . . . . 2-4X2.4 COSTS AND COST EFFECTIVENESS OF NO CONTROLX

TECHNIQUES . . . . . . . . . . . . . . . . . 2-82.5 IMPACTS OF NO CONTROLS . . . . . . . . . . 2-8X

2.5.1 Air Impacts of Combustion Modification Techniques . . . . . 2-12

2.5.2 Air Impacts of SCR and SNCR . . . . . 2-132.5.3 Solid Waste Impacts . . . . . . . . . 2-132.5.4 Energy Impacts . . . . . . . . . . . 2-14

3 INDUSTRY DESCRIPTION . . . . . . . . . . . . . . 3-13.1 BACKGROUND . . . . . . . . . . . . . . . . 3-1

3.1.1 A Historical Perspective . . . . . . 3-23.1.2 An Overview of the U.S. Iron

and Steel Industry . . . . . . . . 3-2 3.1.2.1 Integrated Producers . . . 3-5 3.1.2.2 Mini-Mills . . . . . . . . 3-5 3.1.2.3 Specialty Producers . . . 3-5

3.2 INDUSTRY CHARACTERIZATION . . . . . . . . . 3-83.2.1 An Overview of Iron and Steel

Manufacturing . . . . . . . . . . . 3-8 3.2.1.1 Raw Materials and Preparatory

Processes . . . . . . . 3-8 3.2.1.2 Ironmaking . . . . . . . . 3-10 3.2.1.3 Steelmaking . . . . . . . 3-11 3.2.1.4 Finishing . . . . . . . . 3-14

3.3 PRODUCTION PROCESSES WITH NO EMISSIONS . 3-X3.3.1 Sintering . . . . . . . . . . . . . 3-153.3.2 Cokemaking . . . . . . . . . . . . . 3-173.3.3 Blast Furnaces and Blast Furnace

Stoves . . . . . . . . . . . . . . 3-183.3.4 Basic Oxygen Furnaces . . . . . . . . 3-193.3.5 Soaking-Pit and Reheat Furnaces . . 3-20

3.3.6 Annealing Furnaces . . . . . . . . .3-23

3.4 REFERENCES . . . . . . . . . . . . . . . . . 3-24

4 UNCONTROLLED NO EMISSIONS . . . . . . . . . . . 4-1X4.1 MECHANISMS OF NO FORMATION . . . . . . . . 4-1X

ii

TABLE OF CONTENTS (con.)

4.1.1 Thermal NO Formation . . . . . . . . 4-1 x4.1.2 Fuel NO Formation . . . . . . . . . . . 4-4x4.1.3 Prompt NO Formation . . . . . . . . . . 4-6x4.2 EMISSIONS OF NO FROM IRON AND STEEL MILLS . 4-7X

4.2.1 Emission Factors . . . . . . . . . . 4-74.2.2 Coke-oven Underfiring . . . . . . . . 4-74.2.3 Sintering . . . . . . . . . . . . . . 4-94.2.4 Blast Furnaces and Blast

Furnace Stoves . . . . . . . . . . . 4-104.2.5 Basic Oxygen Furnace . . . . . . . . 4-104.2.6 Electric-arc Furnace . . . . . . . . 4-114.2.7 Soaking Pits . . . . . . . . . . . . 4-124.2.8 Reheat Furnaces . . . . . . . . . . . 4-134.2.9 Annealing Furnaces . . . . . . . . . 4-144.2.10 Galvanizing Furnaces . . . . . . . . 4-154.2.11 Summary . . . . . . . . . . . . . . 4-15

4.3 REFERENCES . . . . . . . . . . . . . . . . . 4-18

5 NITROGEN OXIDES CONTROL TECHNIQUES . . . . . . . 5-15.1 BACKGROUND . . . . . . . . . . . . . . . . . 5-15.2 CONTROL TECHNIQUES APPLICABLE TO IRON AND STEEL

FACILITIES . . . . . . . . . . . . . . . . . 5-15.2.1 Control Techniques Applied . . . . . 5-1

5.2.1.1 Low Excess Air . . . . . . . 5-3 5.2.1.2 Low NO Burners . . . . . . 5-3x 5.2.1.3 Low NO Burner Plus Flue Gasx

Recirculation . . . . . . . 5-8 5.2.1.4 Selective Catalytic

Reduction . . . . . . . . . 5-85.2.2 Other Control Techniques . . . . . . 5-11

5.2.2.1 Off-Stoichiometric or Staged Combustion . . . . . . . . . 5-11

5.2.2.2 Fuel Switching . . . . . . . 5-16 5.2.2.3 Selective Noncatalytic

Reduction . . . . . . . . . 5-165.3 NITROGEN OXIDES CONTROLS FOR SPECIFIC

FACILITIES . . . . . . . . . . . . . . . . . 5-185.3.1 Coke Ovens . . . . . . . . . . . . . 5-185.3.2 Sinter Plants . . . . . . . . . . . . 5-195.3.3 Blast Furnaces and Blast

Furnace Stoves . . . . . . . . . . . 5-215.3.4 Basic Oxygen Furnace . . . . . . . . 5-225.3.5 Electric Arc Furnaces . . . . . . . . 5-23

5.3.6 Reheat Furnaces . . . . . . . . . . . 5-235.3.7 Soaking Pits . . . . . . . . . . . . 5-255.3.8 Annealing and Galvanizing . . . . . . 5-25

iii

TABLE OF CONTENTS (con.)

5.3.8.1 Annealing Furnaces . . . . . 5-25 5.3.8.2 Galvanizing Furnaces . . . . 5-27

5.4 SUMMARY OF CONTROLLED NO EMISSIONS . . . . 5-27X5.5 REFERENCES . . . . . . . . . . . . . . . . . 5-29

6 COSTS OF NO CONTROLS . . . . . . . . . . . . . . 6-1X6.1 STEEL REHEAT FURNACES . . . . . . . . . . . 6-2

6.1.1 Model Furnaces . . . . . . . . . . . 6-26.1.2 Costs and Cost Effectiveness of LEA Control

for Reheat Furnaces . . . . . 6-36.1.3 Costs and Cost Effectiveness of

LNB Control for Reheat Furnaces . . . 6-36.1.4 Costs and Cost Effectiveness of

LNB Plus FGR Control . . . . . . 6-56.2 ANNEALING FURNACES . . . . . . . . . . . . . 6-8

6.2.1 Model Furnaces . . . . . . . . . . . 6-86.2.2 Costs and Cost Effectiveness of LNB

Control . . . . . . 6-116.2.3 Costs and Cost Effectiveness of LNB

plus FGR Control . . . . . . . . . . 6-96.2.4 Costs and Cost Effectiveness of SNCR Control . . . . . . . . . . . . 6-96.2.5 Costs and Cost Effectiveness of SCR Control of Annealing Furnaces . . . . 6-146.2.6 Costs and Cost Effectiveness of LNB plus

SNCR for Annealing Furnaces . . . 6-146.2.7 Costs and Cost Effectiveness of LNB plus SCR Controls for Annealing

Furnaces . . . . . . . . . . . . . . 6-176.3 GALVANIZING FURNACES . . . . . . . . . . . . 6-17

6.3.1 Model Furnaces . . . . . . . . . . . 6-176.3.2 Costs and Cost Effectiveness of LNB

plus FGR Controls for Galvanizing Furnaces . . . . . . . . . . . . . 6-17

6.3.3 Costs and Cost Effectiveness of LNB for Galvanizing Furnaces . . . . . . 6-19

6.5 REFERENCES . . . . . . . . . . . . . . . . . . . 6-22

7 ENVIRONMENTAL AND ENERGY IMPACTS OF NO CONTROLS . . 7-1X7.1 INTRODUCTION . . . . . . . . . . . . . . . . . 7-17.2 AIR IMPACTS . . . . . . . . . . . . . . . . . . 7-1

7.2.1 NO Emission Reductions . . . . . . . . 7-1x7.2.2 Air Impacts of Combustion Modifications . 7-37.2.3 Air Impacts of SCR and SNCR . . . . . . 7-4

7.3 SOLID WASTE IMPACTS . . . . . . . . . . . . . . 7-67.4 ENERGY IMPACTS . . . . . . . . . . . . . . . . . 7-67.5 REFERENCES . . . . . . . . . . . . . . . . . . . 7-8

APPENDIX A TABULATION OF UNCONTROLLED NO EMISSIONS DATA. . . X

iv

LIST OF FIGURES

Number Page

2-1 Simplified steelmaking flow chart . . . . . . . 2-2

3-1 Simplified steelmaking flow chart . . . . . . . 3-9into major steel product forms . . . . . . . . 3-9

3-2 Schematic representation of progress ofrefining in a top-blown basic-lined BOF . . . . 3-21

5-1 Staged-air low NO burner . . . . . . . . . . 5-5x 5-2 Staged-fuel low NO burners . . . . . . . . . . 5-6x 5-3 Illustration of flue gas recirculation . . . . 5-9 5-4 Illustration of the SCR Principle . . . . . . 5-10 5-5 Biased burner firing . . . . . . . . . . . . . 5-13 5-6 Burners out of service (BOOS) . . . . . . . . . 5-14 5-7 Overfire air . . . . . . . . . . . . . . . . . 5-15

v

LIST OF TABLESNumber Page

2-1 SUMMARY OF UNCONTROLLED NO EMISSIONS . . . . . 2-5X 2-2 NO CONTROLLED EMISSIONS AND X

PERCENT REDUCTIONS . . . . . . . . . . . . . . 2-7 2-3 COSTS AND COST EFFECTIVENESS - EXISTING REHEAT FURNACES (300 MMBtu/hr) . . . . . . . . . . . . . . . . . 2-8 2-4 COSTS AND COST EFFECTIVENESS - EXISTING ANNEALING

FURNACES (200 MMBtu/hr) . . . . . . . . . . . . . 2-9 2-5 COSTS AND COST EFFECTIVENESS - EXISTING GALVANIZING

FURNACES (100 MMBtu/hr) . . . . . . . . . . . 2-11 3-1 SUMMARY OF CURRENT STEEL INDUSTRY FACTS . . . . 3-4 3-2 SUMMARY INFORMATION RELEVANT TO INTEGRATED

STEEL PRODUCERS . . . . . . . . . . . . . . . . 3-6 4-1 CALCULATED EQUILIBRIUM CONCENTRATIONS (in ppm)

OF NO AND NO IN AIR AND FLUE GAS . . . . . . . 4-32 4-2 FACTORS CONTROLLING THE FORMATION OF THERMAL NO 4-5X 4-3 NITROGEN OXIDE EMISSION FACTORS FROM AP-42

AND NAPAP . . . . . . . . . . . . . . . . . . 4-8 4-4 SUMMARY OF UNCONTROLLED NO EMISSIONS . . . . . 4-12X 5-1 OVERVIEW OF NO CONTROL TECHNIQUES . . . . . . 5-2X 5-2 NO CONTROLLED EMISSIONS AND PERCENT REDUCTION . 5-28X

6-1 COSTS AND COST EFFECTIVENESS OF LEA FORREHEAT FURNACES. . . . . . . .. . . . . . . . . . 6-4

6-2 COSTS AND COST EFFE