Fuel Flexibility with Biomass for Coal Boilers at University of Iowa Ben Anderson – University of Iowa Andy Ungerman – Stanley Consultants

Agenda Introductions Overview & Biomass Initiatives Permitting Strategy Project Design & Biomass Considerations Project Construction Startup & Lessons Learned Future Plans Conclusions & Questions

Introductions Ben Anderson – University of Iowa – Power Plant Maintenance & Engineering Manager – BSME from Iowa State University – Petro-chemical background Andy Ungerman - Stanley Consultants – Mechanical Engineer – Energy Business Group – BS & MSME from Iowa State University – Power Plant Consulting Background

Overview University of Iowa – Main Power Plant – 4 Boilers: 600+ klb/hr, 3 Turbine Generators MW – 6 offsite natural gas and 1 biomass boilers 135,00 lbs/hr 140,00 lbs/hr

Biomass Initiative University of Iowa - Biomass Initiative – Achieve the goal of 40% renewable energy consumption on the campus by 2020 – More info at

Permitting Strategy BLR 10 Biomass – IDNR to issue permit on 12/2011, failed PM 10 test, permit closed – New permit submitted several months ago Wood chips, yard trimmings, paper sludge – Cedar Rapids Landfill & other local sources Update with Fuel grasses – miscanthus Expect approval in next month – Increased reporting Track fuels usage Frequent fuel sampling (ensure below PSD for NOx, SO2, and PM2.5) BLR 11 Biomass – Current permit for oat hulls – Approved variance to burn wood chips Collaboration with state park to dispose of 2500 tons of pine Plan to have permanent change submitted in early February Plant wide Applicability Permit (PAL) submitted to IDNR

Project Design - Overview

~16° incline, tubular gallery 75 ton bunker (8 hr supply) Extensive reinforcement and modification to existing structures Gravimetric feeder w/ conical distributor Equipment located for future biomass equipment Compact, cartridge dust collectors Project Design - Overview Completely insulated enclosures and galleries

Project Design: Co-firing with Biomass UT Distributors for Biomass Woodchip/Biomass issues – non uniform sizing 1 Volumetrically limited – Max 15% Biomass (soft number) – assuming sizing is similar 1 -15% vol blend = 6% by weight = 3% by BTU (assuming woodchip density of 20 lb/ft 3, and a heating value of 4,500 Btu/ft 3 ) Closer the properties to coal, higher the percent 1 – 100%? -Pelletized or torrified wood etc. Non-Segregated Distributor Woodchip/biomass issues – non uniform sizing Different sizing may lead to segregation Lack of data on biomass Closer properties are to coal, the better 1 Per information received from Detroit Stoker Corp, used with permission.

Project Design: Co-firing with Biomass with Stoker Boiler Best Arrangements for Co-Firing Wood 1 Separate fuel trains Different fuel sizing = separate trains Goal is to get good ash bed on grate and uniform distribution Symmetry is important! UTs 1 and 5 or 2 and 4 Combo Feeders lbs/in of feeder (Qty 2 feeders = 54 kpph) Recommended fuel drop height = 10 ft Distributes fuel lower in furnace (preferred) Requires header to be moved Air swept spouts 1 50% of grate to be covered with spouts (20’ grate requires four 30” air spouts) Location = higher in furnace Tube bending vs. moving header Must get around non-seg distributor 1 Per information received from Detroit Stoker Corp, used with permission. Combo Feeders Air swept spouts

Unique design – grav. feeder w/ non-seg dist. 75 ton (coal) bunker can be offset further compared to batch-type feeder. Allows emergency unloading Future biomass robbing screws and hoppers can be fed by a “surge bin” fed from a separate material handling system using a new silo Detroit Stoker UT Distributor hoppers modified to allow for future Combo feeders. Bunker could be modified to bottom reclaim (remove bottom cone) Future Biomass Flexibility at UOI 75 Ton Bunker Drag chain Surge hoppers & robbing screws UT hoppers allow for future Combo feeders. Feeder/Non Seg Offset Future

Comparison of Fuels and Mat’l Handling for Boiler 10 Stoker Coal Wood Chips 85% Coal 15% Wood (Volume) Boiler 10 MCR Steam Flow, lb/hr170,000135,000*170,000 Boiler 10 Fuel Flow, MMBtu/hr Approx. Heating Value, Btu/lb11, *11,131 Boiler 10 Fuel Flow, ft 3 /hr3682, Conveyor Capacity, tph Conveyor Belt Speed, fpm Belt Loading, % Conveyor Capacity, ft 3 /hr Time to Empty Bunker w/ Boiler 10 at MCR, hr * Heat input and Heating value taken from Biomass Conversion Study Report (2010) for UOI by Riley Power. Used with Permission.

Project Construction Logistics Equipment Fabrication Crane - Gallery & Conveyor install Boiler Shutdown and Dense Phase Demo Start-up & Lessons Learned

Project Construction – Logistics Iowa River Campus Location Space Constraints – Equipment laydown – Contractors

Project Construction – Equipment Fabrication Schedules Manufacturing visits Delivery

Project Construction - Crane Logistics – 20+ semi tucks Ground survey – Voids – Flat surface Crane location & continued plant ops

Project Construction - Installation

Project Construction - Boiler Shutdown & Dense Phase Demo Major 3+ month outage – Boiler maintenance – Boiler lay-up Planned start-up on 11/30/12 Back-up boiler installed

Start-up & Lessons Learned Permitting & Construction Timing Commissioning & Training CHS operational - several nuisance trips – Alignment switches; belt tracking – CO monitors – VFD Fault on gravimetric feeder – Plugged conveyor Alarm Rationalization (CO, Alignment switches) Cleanliness

Future Plans Full inspection and baseline on boiler (complete) Burn wood chips in near future (ASAP) Begin developing test runs for other fuels (Ongoing) Installing natural gas burner Spring 2013 Internal inspection at regular intervals (Ongoing) Modifications to fuel handling system for increased Biomass combustion

Conclusions Develop solid Biomass plan Design projects to be flexible for future conversions Work on permitting strategy early and plan for good discussions Complete equipment scenario/what-if analysis and implement into planning/design

Questions