Dow Freeport PMDI
MRU Optimization
John Litzinger
Sr. Improvement Specialist
May 20, 2010
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About Dow
• Largest diversified chemical company
• Founded in Midland, Michigan in 1897
• Supplies more than 5,000 products to
customers in 160 countries
• Annual sales of $45 billion
• 52,000 employees worldwide
• One of the world’s largest industrial energy
consumers
• Committed to Sustainability
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Oil & Gas = Energy & Feedstock
Feedstock
Ethane, Propane
Butane, Naphtha
Oil & Gas
850,000 Barrels/day
Energy
Steam, Heat
Power, Water
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Corporate Commitment to Energy Reduction
Public Commitment:
• In 1995 Dow Committed:
• To Reduce Energy Intensity
• By 20% by the year 2005
• From Base Year 1994
The Dow Public Report
www.dowpublicreport.com
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Corporate Commitment & Acountability
Corporate Commitment to 2015 Goals
 We will further reduce our global energy intensity by 25% from 20052015
 We will reduce our GHG emissions intensity by 2.5 % per year thru
2015
 By 2025, we aspire to reduce absolute emissions within the company
“No one in the world is more intensely
aware of the need, ultimately, to reinvent
our dependency on oil and natural gas
than we are… We will lead the way on
energy transformation because we have to.
And we have taken important steps already.”
-- Andrew Liveris
Chairman, CEO & President
The Dow Chemical Company
Liveris Launches 2015 Sustainability Goals
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Dow Polyurethane PMDI
• PMDI (Polymeric Methylene Di-Phenyl
Di-Isocyanate) is a raw material in
Polyurethane Formulations.
– Typical end uses include insulation in
Appliances and Construction industries.
– Dow directly markets Great StuffTM
insulation foam.
• Product end use is directly related to
energy efficiency improvements in
everyday life.
• Dow Operates 3 PMDI sites within
integrated sites – Freeport, TX; Stade,
Germany; Estarreja, Portugal
TM
– Trademark of the Dow Chemical Company
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PMDI Energy Efficiency Program
In 2005, Dow started up a new PMDI facility
in Freeport, TX, with 500 MM lb/year capacity
In 2007, the business started an energy
efficiency improvement plan with the
following results:
– High Pressure Steam Optimization / Trap
Reliability
– Thermal Oxidizer Fuel Gas Optimization
– Internal Reflux and Reboiler Optimization for
several distillation columns
– Furnace Optimization including majority use
of Hydrogen when available
– Mechanical Refrigeration Unit (MRU)
Compressor Optimization
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MRU Optimization Summary
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Project Overview
Approach
Team Resources
Phase 1 Implementation and Results
Phase 2 Implementation and Results
Final Summary
Q&A
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Project Overview
• Desired outcome was to reduce electricity
usage while maintaining required process
cooling.
– The MRU Compressor is a 15,000 HP system with 3
stages and 8 impellers.
– Due to plant optimization, the requirements for
cooling are 30% less than design.
• The project was implemented in 2 phases
– Maximize improvements with no hardware changes
– Maximize improvements with minimized capital
spending, and maximize Net Present Value (NPV)
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Approach
• First Pass - Used compressor curves to
determine if unit could be turned down as is
• Worked with compressor manufacturer to
confirm using its internal modeling system
• Dow Process Engineering confirmed modeling
results using AspenTM simulation programs.
• Tested in field, confirming surge first, then full
implementation of Phase 1
• Once confirmed, moved to Phase 2 –
Hardware changes
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Team Resources
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Improvement Engineer
Process Engineer
Mechanical Design Lead
Technology Consultant
Rotating Equipment Specialist
Refrigeration Consultant
Mechanical Engineer
Reliability Engineer
Plant Operations Staff
Vendor Input
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Phase 1 – No Investment (August 2009)
• Team reduced Compressor HP by 16%
• Overall approach was to create a higher DP, with
lower flow on Stages 2 and 3 (left on the curve).
• On Stage 1, volume flow was increased (moving
right on the curve)
– Maintain proper cooling conditions
– Minimize false loading throughout the system
• Surge testing was attempted, but never confirmed
since plant was operational
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Phase 2 – Minor Capital (February 2010)
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Team reduced Compressor HP by additional 17%
– Met goal of 30% energy reduction corresponding to refrigeration load
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Evaluated different hardware options –
– Replace shaft and impeller wheels
– Trim existing impeller wheels
– Resize Gearbox Reducer
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Implemented “Resized Gearbox Reducer”
– Decreased Compressor Shaft speed by 5%
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Replaced during one-week outage in February
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Started compressor when plant was still down to test surge
Surge confirmed on Stage 3, and tested minimum flows on Stage 1 and 2.
Placed “anti-surge” set points at 10% above “tested” on Stage 1 and 2.
Placed “anti-surge” set point at 20% above for Stage 3.
Current Operations
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Zero false load on Stage 3
Minimum false load on Stage 2
Low false load on Stage 1
Proper pressure and exchanger level set points
to maintain refrigeration
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Final Summary
• Project Value
– $2,500,000 savings
– 17,330 tons CO2 reduced
– Invested hardware cost approximately $250,000 in
Phase 2
• Project approach can be adopted throughout
Dow, and may already be implemented
throughout industry.
– De-rates are especially important when electricity is
perceived as fixed cost, and energy requirements
are lower downstream.
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Q&A
Thank You
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