Refractory Wear During Gasification Larry Baxter 1, Shrinivas Lokare 1, Humberto Garcia 2, Bing Liu 1 Clearwater Coal Conference Clearwater, FL June 2, Brigham Young University Provo, UT 2 Idaho National Laboratory * Idaho Falls, ID

Gasification in the Literature

Research by Country

Levelized Cost of Power

GE Energy Radiant Coal Slurry 63 wt.% 95% O 2 Slag/Fines Syngas 410°F, 800 Psia Composition (Mole%): H 2 26% CO 27% CO 2 12% H 2 O 34% Other 1% H 2 O/CO = 1.3 Design: Pressurized, single-stage, downward firing, entrained flow, slurry feed, oxygen blown, slagging, radiant and quench cooling To Acid Gas Removal or To Shift

ConocoPhillips E-Gas™ Coal Slurry 63 wt. % Stage 2 95 % O 2 Slag Quench Char Slag/Water Slurry Syngas 1,700°F, 614 psia Composition (Mole%): H 2 26% CO 37% CO 2 14% H 2 O 15% CH 4 4% Other 4% H 2 O/CO = 0.4 (0.78) (0.22) Stage 1 2,500 o F 614 Psia To Fire-tube boiler Design: Pressurized, two-stage, upward firing, entrained flow, slurry feed, oxygen blown, slagging, fire-tube boiling syngas cooling, syngas recycle To Acid Gas Removal or To Shift

Shell Gasification Syngas 350°F, 600 Psia Composition (Mole%): H 2 29% CO 57% CO 2 2% H 2 O 4% Other 8% H 2 O/CO = 0.1 Dry Coal Design: Pressurized, single-stage, downward firing, slagging, entrained flow, dry feed, oxygen blown, convective cooler Convective Cooler Soot Quench & Scrubber 95% O 2 HP Steam 650 o F Steam Source: “The Shell Gasification Process”, Uhde, ThyssenKrupp Technologies Syngas Quench 2 To Acid Gas Removal or To Shift HP Steam Slag Gasifier 2,700 o F 615 psia

Transient Model Formulation

Simulation – Gas Phase

Efficiency Calculation

Impaction Efficiency Improvement abcd Potential Flow Viscous Flow

Corrosion potential KClS Si Ca Fe Chlorides condensation is a major step in corrosion initiation

Complex Inorganic Chemistry

Al 2 O 3 -CaO-SiO 2 Chemistry Al 2 O 3 /SiO 2 = 0.34

Refractory-Slag Model

Slag Importance

Refractory Wear with Time

Sensitivity to CaO content

Refractory Chemical Corrosion

Spalling Mechanisms

Overall Refractory Wear Chemical dissolution rates depend in complex ways on diffusivities, viscosities, chemical reactions, and temperature. Spalling mechanisms and rates are not well understood, with quantitative models being mostly empirical. Net dissolution rates disproportionately depend on minor slag and refractory components, involving complex inorganic chemistry.

Spalling Mechanisms Spalling Corrosion

Spalling Mechanisms Chemistry (weight %) Point Al Si Fe Ca Cr Crystalline Phaseshercynite, fayalite, enstatite, Iron sulfide, iron cordierite, hermatite iron-alumina spinel iron-chrome spinel Chromia/alumina solid solutionFe-depleted slagAl build-up with Si

Refractory/Slag Profile Distance from Hot Face (mm) Bulk Chemistry (wt pct) X-Ray Crystalline Phases Cr 2 O 3 Al 2 O 3 SiO 2 CaOFe H.F. to P= Cr 2 O 3 Tr=M*Cr 2 O P= Cr 2 O 3 Tr=M*Cr 2 O P= Cr 2 O 3 Tr=M*Cr 2 O P= Cr 2 O P= Cr 2 O P= Cr 2 O P= Cr 2 O P= Cr 2 O 3

Conclusions Chemical dissolution and spalling account for most refractory wear. Both mechanisms depend on temperature, slag/refractory composition, and slag flow rates, approximately in that order. Temperature dependence arises from both transport and solubility issues. Both immersion and spinning cup analyses provide good corrosion information, but neither simulates practical systems. Temperature, not peak deposition rates, determine maximum corrosion location.

Acknowledgements PhD and post-doc students Shrinivas Lokare, Bing Liu developed many of the submodels. Partial financial support from U.S. Department of Energy contract DE-AC07-05ID14517 and from corporate sponsors.