Modeling ash deposition and shedding during oxy-combustion of coal/rice husk blends at 70%inlet O_(2)  

作　　者：Gautham Krishnamoorthy 

机构地区：[1]Department of Chemical Engineering,UPSON Ⅱ Room 365,241 Centennial Drive,University of North Dakota,Grand Forks,ND 58202-7101,USA

出　　处：《International Journal of Coal Science & Technology》2023年第2期196-209,共14页国际煤炭科学技术学报（英文）

基　　金：funded through the University Coal Research Program being administered by DOE-NETL (Award Number:DE-FE0031741).

摘　　要：Co-firing rice husk(RH)and coal with carbon capture using oxy-combustion presents a net carbon negative energy produc-tion opportunity.In addition,the high fusion temperature of the non-sticky,silica rich,RH can mitigate ash deposition as well as promote shedding of deposits.To identify the optimum operating conditions,fuel particle sizes,and blend ratios that minimize ash deposition,a Computational Fluid Dynamic methodology with add-on ash deposition and shedding models were employed to predict outer ash deposition and shedding rates during co-combustion of coal/RH in AIR and O2/CO_(2)(70/30 vol%,OXY70)oxidizer compositions.After ensuring that the fly-ash particle size distributions and particle Stokes numbers near the deposition surface were accurately represented(to model impaction),appropriate models for coal ash and RH ash viscosities that were accurate in the temperature region(1200-1300 K)of interest in this study were identified.A particle viscosity and kinetic energy(PKE)based capture criterion was enforced to model the ash capture.An erosion/shed-ding criterion that takes the deposit melt fraction and the energy consumed during particle impact into account was also implemented.Deposition rate predictions as well as the deposition rate enhancement(OXY70/AIR)were in good agreement with measured values.While the OXY70 scenario was associated with a significant reduction(60%-70%)in flue gas velocities,it also resulted in larger fly-ash particles.As a result,the PKE distributions of the erosive RH ash were similar in both scenarios and resulted in similar shedding rates.

关 键 词：CFD OXY-COMBUSTION Ash Deposition SHEDDING CO-FIRING 

分 类 号：TD82[矿业工程—煤矿开采]