Recent Trends in Heat Recovery Cokemaking Processes - ABM

Recent Trends in Heat Recovery Cokemaking
Processes
Dr. John F. Quanci
SunCoke Energy
Vice-President of Technology
September 2011
September 2011 SunCoke Energy 1

Outline
• Iron Production: Coke Usage
• Heat Recovery Cokemaking Technology History
• Heat Recovery Cokemaking: Current Practice
• Future Requirements and Direction in Heat Recovery
September 2011 SunCoke Energy 2

Iron Production: Coke Usage
September 2011 SunCoke Energy
3

Iron Production: Coke Minimization
• Coke is the 2 nd highest cost consumable in Steel
production
– ~25% of the total cost
– Iron highest at ~40% of total cost
• Blast furnace competitiveness depends on lowering
coke use
• Steel Industry focused on lowering coke use for the
last 50 years by advances in practices and technology
September 2011 SunCoke Energy 4

Reduction Blast Furnace Reducing Agent Consumption
Impact of Technology over the last 50 years:
• Reducing Agents lowered by over 50%
• Coke use lowered by over 65%
September 2011
consumption of reductants kg/thm
1100
1000
900
800
700
600
500
400
300
200
100
0
Ore beneficiation
Input of overseas rich ores
Blast temperature > 1200C
O2 enrichment
Top pressure
Burden distribution
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
year
Gas flow control
Improvement of Fe burden
~30%
Improvement of coke
Source: Sponge Iron Production - Chatterjee
Small coke in Fe burden
104
33
345
coal
oil + others
coke
482
SunCoke Energy
5

Global Demand for Coke and Hot Metal
Source: US Geological Survey
• Even though Steel Companies driving down coke/thm through technology and alternate
reductants, coke demand still increasing
• Increasing demand for coking coals expected
September 2011 SunCoke Energy 6

Alternate Reductants for Coke Replacement
• Increased use of PCI and other reductants to replace coke in
Blast Furnaces
• As high as 30-40% of blast furnace coke has been replaced by
alternate reductants like PCI
• Alternate reductants could potentially make up as much as
50% of the total reductant
• As alternate reductants like PCI increase, higher quality coke
needed:
– Supports the burden (about 50% of total reductant)
– Distributes gases
• Will drive demand for larger and stronger coke!
September 2011 SunCoke Energy 7

Heat Recovery Technology History
September 2011 SunCoke Energy 8

Sun Coke
Process Flow Diagram
SunCoke Energy – Process Flow Diagram
Coal 1,930 F Flue Gas temperature
Flue Gas
Treating
for Sulfur
Removal
ID Fans
Coal - Blended
VM 24.50
FC 68.25
Ash 7.25
Moisture 7.00
Heat Recovery Coke Ovens
Steam
Extracted
for Process
Use
Turbine
Electricity to Grid
Emergency
Stack
Run-of-Oven
Coke
Furnace coke
Breeze
Heat Recovery
Steam Generators
Co-generation Plant
Condenser
Feed Water
Heaters, Pumps,
Deaerators
September 2011 SunCoke Energy 9
Main Stack

SunCoke Energy – Horizontal Heat Recovery Oven
September 2011 SunCoke Energy 10

Horizontal Non-Heat Recovery – Developmental History
• 1960s
– First SunCoke Horizontal Mitchell Ovens in Jewell
• 1970s
– Jewell Thompson ovens built
– Precursor to modern HHR design
• 1980s
– Continued R&D
– Highest quality coke in US
Jewell Plant – late 1980s
Jewell Plant – Vansant, VA
(Mid-1970s)
September 2011 SunCoke Energy 11

1990s – First Generation Heat Recovery Plant
• SunCoke builds first heat
recovery plant in world
• Located in East Chicago, Indiana
• Started up in March 1998
• Coke capacity: 1.3M tpa (268
ovens)
• Heat Recovery of 1.0 Mlbs/hr of
superheated steam
• Rated for 100 MW of power
generation
Indiana Harbor Coke Plant – March 1998
September 2011 SunCoke Energy 12

SunCoke Energy History since 2000 – New HR Plants
Domestic Operations
Granite City (2009)
120 Ovens
Capacity: 650kt
Steam: 450klbs/hr
Indiana Harbor
268 Ovens
Capacity: 1,220kt
Steam: 1,000klbs/hr Haverhill (2005, 2008)
200 Ovens
Capacity: 1,100kt
Steam: 450klb/hr
Power: net 46 MW
Jewell Coke
142 Ovens
Capacity: 720kt
Middletown (1)
100 Ovens
Capacity: 550kt
Power: net 46 MW
Existing coke facilities
Coke facility under construction
(1) Expected start-up in Q4 2011.
(2) SunCoke holds a preferred interest of $41 million in Vitória and is the operator.
International Operations
Brazil
Vitória (2) (2007)
320 Ovens
Capacity: 1,700kt
Power: 150 MW
September 2011 SunCoke Energy 13

SunCoke Heat Recovery Plants
Vitoria, ES – Brazil (320 Ovens)
Haverhill, OH – Phase II (100 Ovens)
September 2011 SunCoke Energy 14

Most recent project – Middletown, OH
September 2011 SunCoke Energy 15

SunCoke Energy Capacity through 2011
• Steady increase in SunCoke Energy heat recovery coking capacity over the last 5 – 10 years
• All new coke plants in United States since 2000 have been Horizontal Heat Recovery
September 2011 SunCoke Energy 16
Heat Recovery Capacity

Last 5-Year Technology Advancements
• Improved Oven Design
• Improved HRSG design
• Pusher charger machine upgrades
• Flat push hot car & quench car
• Further enhanced charging
emission control system
• Advanced FGD Control
– EPA Approved Technology
• Improved Quench Tower Design
September 2011 SunCoke Energy
17

Heat Recovery Cokemaking:
Current Practice
September 2011 SunCoke Energy 18

Typical SunCoke Energy Battery
• Coal specifications
– Typical volatile matter is 21% to 28%, campaign 19% to 32%
– Average reflectance range of 1.00 to 1.65
• Can generate steam or power
– Approximately 9 MW / 100 kmt annual Run of Oven coke production
– Annual power production of 788 kW-h / mt coke
• No wastewater treatment plant required
• Can be constructed on a new site or existing site (brownfield)
• 48 hour cycle / 43.2 metric tons (48 short tons) coal
• 1540C max temperature
• Plant designed for 30 year run life
• Approximately 2 – 4% Yield Loss
• 2 – 5 CSR increase over By-product plant using same coals
– Improved Strength attributed to slower heating rate, higher temperatures and longer soak
time resulting in consistent crystal growth
September 2011 SunCoke Energy 19

• Not limited by coal expansion
– Can use high wall-pressure coals
– Can use low and high rank coals
HHR Coal Flexibility
• SunCoke demonstrated use of PCI coal (25%), Petroleum Coke (10%), noncoking
coal (10%), soft or semi-coking coal (25%) and breeze with minimal
impact to CSR
• No oven damage risk associated with blend changes
– Minimal need to run pilot/moveable wall oven studies
• Less risk of exposure to coal supply shortages / issues
– SunCoke Energy facilities can change coal blends weekly
– Up to 80+ different coal blends used per year
September 2011 SunCoke Energy 20

Heat Recovery Oven Flexibility
Hypothetical
blend of 3 coals
HR &
By-Product
• Heat recovery plants can blend in more high pressure coals
HR only
• Elimination of wall pressure constraints increases blend flexibility
HHR Not constrained
to this maximum
September 2011 SunCoke Energy 21

Environmental Impact Benefits
• Low VOC emissions
– Ovens operate under negative pressure conditions during coking cycle
– Complete combustion of VM
• SunCoke Energy sets the technology standard in United States
– SDA / baghouse is typical
– Successfully integrated advanced FGD with coking process
• No net waste-water discharge
– All process water consumed by quenching
September 2011 SunCoke Energy 22

Factors Favoring Heat Recovery Plants
• Minimal need for COG in the steel plant
• High cost of electricity or no electricity supply available
• Steam required for process needs
– HHR is a Cogen plant and can replace existing boilers
• Coal blend flexibility (no wall pressure limits)
– Can utilize wide range of coals (lower cost blends)
– Plant location at risk for coal supply disruptions
• Strict environmental regulations
• No or limited waste water treatment plant
• Higher quality coke is required
– Large blast furnaces and/or high PCI rates
September 2011 SunCoke Energy
23

Future Trends in Heat Recovery
Cokemaking

SCE Horizontal HR Coke Plant Improvement Summary
Critical Areas for Customers Next Plant Future Plants
Footprint Potential 30% Smaller >30% Smaller
Capital Cost Value Engineered -
Lower Capital
Further Capital Decrease Driven by
Footprint
Coke Yield Lower Yield Loss Increased Yield Gain
Lower Coal Cost Flexibility for Stamp Charging
Predictive coal blend modeling
improvements
New Designs
Turndown Greater than 25% >50% and Turn Off
Environmental Regs Meet or exceed New EPA Regs Exceed EPA Regs
Continue to set the standard
Oven Operation/Life New Monitoring Tools Structure
Improvements
New Materials of Construction and
CFD/FEA
Increased Power New HRSG Design Further Improvements based on
CFD
September 2011 SunCoke Energy 25

Value Engineering Coke Plant: Conceptual Designs
• Value engineering can reduce capital investment
– Maintain coke rate with less supporting capital equipment
– Reviewed existing design and reduced number of machines
– Also looking to use low-cost country sourcing
• Design Enhancements
– Plot space saving
– Simplified power production design
– Meets or exceeds new Environmental requirements
• Modular expansion provides more flexibility for “brownfield”
sites
September 2011 SunCoke Energy 26

Coke Yield Improvements
• Currently studying parameters that effect the Run of Oven
coke yield
• Goal is to minimize burn loss through fundamental design
changes of the coke oven
• Ties in very well with future modeling work (CFD and
combustion kinetics)
September 2011 SunCoke Energy 27

Low Cost Coal Utilization
• Horizontal Heat Recovery ovens have blend advantage since no
wall pressure limit
– Larger selection of low quality and low cost coals
• Coal Compaction/Stamp charging has high potential to lower
overall coke cost
– Significantly reduce coal costs and maintain high coke quality
– Required in India/China where large quantities of low quality coal
– International coke producers claim 40 to 60% low quality coal usage in coal
blends
• Coal/Coke Blend Modeling is crucial to take advantage of Coal
Flexibility and Stamp Charging
September 2011 SunCoke Energy 28

Coal/Coke Chemistry and Blend Modeling
• Advance fundamental knowledge of the coking process
• Coal blend/coke prediction model for world-wide applications
• Optimization of coal/coke blends through first principle
modeling
– Go beyond current empirical correlations
– Function of Operating Conditions, Coal Properties and Reaction Kinetics
– CSR, Stability, Yield, Power, etc
• Coal/Coke Non-Linear Program Optimization Tool
• Pilot plant and large-scale testing for coal blend testing, model
development and next generation coke oven design
September 2011 SunCoke Energy 29

Model Development: Coal Blends
log(fluidity)
Coal 1
Planned test Space
optimal
coking range
Coal 2
Coal 3
reflectance
• Develop coal blends/models with non-linear multidimensional optimization and design of
experiment
• Pilot Plant studies allow for non-production viable blends to be tested for the purpose of
statistical leverage on model building and testing
September 2011 SunCoke Energy 30

Computational Fluid Dynamics (CFD) Oven
Temperature
(°F)
Model
• Advance coke making science, technology and principles through the use and application of Advanced
Computational Tools (CFD/FEA/Rxn Kinetics)
• Link CFD, coke/coal blend/kinetic models and oven structural FEA models to allow fully integrated design and
optimization
• Using CFD to optimize oven design and operation; lower yield loss, faster rates, new designs etc
September 2011 SunCoke Energy 31

Coke Oven Turndown Optimization
• Allow flexibility for industry turndowns and coal shortages
• Safe , efficient, and quick turndown of SCE oven without
damage to the oven structure or life while maintaining coke
yield and quality
• Improve Max turndown on existing plant
– Ovens have been turned down greater than 25%
– Further tests may show greater turndown possible
• Improvements to allow more turndown and potentially turn
off existing ovens
September 2011 SunCoke Energy 32

Next Generation Environmental Control
• Next North American Plant to meet or exceed EPA regulations
– Lower SOx
– No planned venting
– Still lowest in HAP’s/VOC’s since negative pressure
• Improved Quench Tower Design
– Lower Emissions
– Better Reliability
– Faster and more efficient quenching
• Environmental Controls can be optimized to meet local
requirements and needs
September 2011 SunCoke Energy 33

Next Generation Coking Process
• Future Goals
– Lower Capital Cost and Lower Cost of Conversion
– High Turndown (turn off)
– Improved HRSG/FGD reliability and integration
– Low yield loss (9 MW/100k mtpa Coke)
– Smaller Footprint Coke Plant
– Improved Coke Quality
– Maximize low quality coal
– Increased throughput over current designs
– Meet or exceed Environmental requirements
September 2011 SunCoke Energy 34

Summary
• SunCoke Energy has advanced horizontal heat recovery
technology over the last 50 years
– Oven design perfected from 1960s to 2010s
– Currently looking to optimize heat recovery and push the limits of
technology
• Will continue to improve the Heat Recovery process
– Better coal blend predictions
– Lowest possible turndown capabilities
– Advanced process modeling for optimal operation
– Smaller footprint with lower CapEx and OpEx costs
– Improved Environmental Controls
• Aspiring to bring science to the art of cokemaking
September 2011 SunCoke Energy 35