ORNL/TM-2011/399 SUPERHEATER CORROSION IN BIOMASS BOILERS: Today’s Science and Technology September 30, 2010 W. B. A. (Sandy) Sharp SharpConsultant DOCUMENT AVAILABILITY Reports produced after January 1, 1996, are generally available free via the U.S. Department of Energy (DOE) Information Bridge. Web site http://www.osti.gov/bridge Reports produced before January 1, 1996, may be purchased by members of the public from the following source. National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone 703-605-6000 (1-800-553-6847) TDD 703-487-4639 Fax 703-605-6900 E-mail [email protected] Web site http://www.ntis.gov/support/ordernowabout.htm Reports are available to DOE employees, DOE contractors, Energy Technology Data Exchange (ETDE) representatives, and International Nuclear Information System (INIS) representatives from the following source. Office of Scientific and Technical Information P.O. 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The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. ORNL/TM-2011/399 Industrial Technologies Program SUPERHEATER CORROSION IN BIOMASS BOILERS: TODAY’S SCIENCE AND TECHNOLOGY W. B. A. (Sandy) Sharp September, 2010 Prepared by OAK RIDGE NATIONAL LABORATORY Oak Ridge, Tennessee 37831-6283 managed by UT-BATTELLE, LLC for the U.S. DEPARTMENT OF ENERGY under contract DE-AC05-00OR22725 CONTENTS LIST OF FIGURES ................................................................................................................................ v LIST OF TABLES ............................................................................................................................... vii ACRONYMS ........................................................................................................................................ ix ACKNOWLEDGMENTS ..................................................................................................................... xi EXECUTIVE SUMMARY ................................................................................................................. xiii 1. INTRODUCTION .............................................................................................................................. 1 1.1 MOTIVATION TO USE RENEWABLE FUELS ....................................................................... 1 1.2 INTRODUCTION TO RELATIONSHIP BETWEEN STEAM TEMPERATURE AND HEAT RECOVERED FROM FUEL ............................................................................................................ 3 1.3 INTRODUCTION TO TYPES OF BOILERS USED TO BURN BIOMASS ............................ 3 1.4 INTRODUCTION TO CORROSION ISSUES IN BIOMASS FUEL BOILER SUPERHEATERS ............................................................................................................................. 5 1.5 INTRODUCTION TO HIGH TEMPERATURE CORROSION MECHANISMS IN SUPERHEATER ALLOYS ............................................................................................................... 5 1.5.1 Rate Limiting Steps .............................................................................................................. 5 1.5.2 Effects of Alloying Elements ................................................................................................ 7 1.5.3 Effects of Sulfur .................................................................................................................... 7 1.5.4 Effects of Chlorine ................................................................................................................ 7 2. CORROSION IN BLACK LIQUOR RECOVERY BOILER SUPERHEATERS ............................ 9 2.1 INTRODUCTION........................................................................................................................ 9 2.2 PARTICLE CARRYOVER AND STICKY DEPOSITS .......................................................... 10 2.3 CORROSION RESISTANCE OF CANDIDATE ALLOYS .................................................... 11 2.4 CORROSION CONTROL STRATEGIES ................................................................................ 13 2.5 SUMMARY ............................................................................................................................... 14 3. CORROSION IN Na2SO4-NaCL GAS TURBINE ENVIRONMENTS, ESPECIALLY NEAR AND ABOVE THE FIRST MELTING TEMPERATURE OF DEPOSITS ....................................... 15 3.1 INTRODUCTION TO GAS TURBINE MATERIALS ............................................................ 15 3.2 CORROSION IN GAS TURBINE ENVIRONMENTS ............................................................ 15 3.3 SUMMARY ............................................................................................................................... 16 4. CORROSION IN COAL-FIRED BOILER SUPERHEATERS, ESPECIALLY NEAR AND ABOVE THE FIRST MELTING TEMPERATURE OF FLUE GAS DEPOSITS ............................. 17 4.1 INTRODUCTION...................................................................................................................... 17 4.2 MATERIALS FOR ULTRA-SUPERCRITICAL COAL-FIRED POWER PLANTS .............. 17 4.2.1 US Research to Develop Materials for Ultra-supercritical Coal-fired Power Plants .......... 17 4.2.2 Research in Other Countries to Develop Materials for Ultra-supercritical Coal-fired Power Plants ........................................................................................................................................... 19 4.3 EFFECT OF CHLORINE IN COAL ON BOILER CORROSION ........................................... 20 4.3.1 Effect of Temperature Gradients ........................................................................................ 22 4.4 FOULING TENDENCY AND ASH DISPOSAL ..................................................................... 24 4.5 EFFECTS OF OXYFUEL COMBUSTION .............................................................................. 25 4.6 EFFECTS ON CORROSION OF CO-FIRING BIOMASS WITH COAL ............................... 26 4.7 SUMMARY ............................................................................................................................... 31 5. CORROSION IN SUPERHEATERS OF BOILERS BURNING MUNICIPAL WASTE AND TIRE-DERIVED FUEL, ESPECIALLY NEAR AND ABOVE THE FMT ....................................... 32 5.1 CO-FIRING WASTES WITH FOSSIL FUELS ........................................................................ 32 5.2 EFFECTS OF CHLORINE IN COMBUSTED WASTES ........................................................ 32 5.3 EFFECTS OF ZINC AND LEAD IN COMBUSTED WASTES .............................................. 33 5.4 CORROSION MONITORING IN WASTE-TO-ENERGY PLANTS ...................................... 35 iii 5.5 EFFECTS ON CORROSION OF CO-FIRING TIRE-DERIVED FUEL WITH COAL .......... 35 5.6 SUMMARY............................................................................................................................... 35 6. CORROSION IN SUPERHEATERS OF BOILERS BURNING AGRICULTURAL BIOMASS, ESPECIALLY NEAR AND ABOVE THE FIRST MELTING TEMPERATURE ............................ 37 6.1 POLICY ISSUES DRIVING THE USE OF BIOMASS FUELS ............................................. 37 6.2 CHARACTERISTICS OF BIOMASS FUELS ......................................................................... 38 6.3 EVALUATING BIOMATERIALS AS BOILER FUELS ........................................................ 39 6.3.1 Wood Products as Biomass Fuels ...................................................................................... 39 6.3.2 Straw as a Biomass Fuel ..................................................................................................... 40 6.3.3 Rice Husk as a Biomass Fuel ............................................................................................. 42 6.3.4 Salix as a Biomass Fuel ...................................................................................................... 43 6.3.5 Rapeseed as a Biomass Fuel ............................................................................................... 43 6.3.6 Uncommon Biomass Fuels ................................................................................................. 43 6.4 CO-FIRING BIOMASS WITH OTHER FUELS ..................................................................... 43 6.5 EVALUATING MATERIALS PERFORMANCE IN BIOMASS BOILER SUPERHEATERS ......................................................................................................................................................... 44 6.6 EFFECTS OF BIOMASS CHLORINE ON SUPERHEATER CORROSION MECHANISMS ........................................................................................................................................................