Fireside Corrosion in Oxy-Fuel Combustion of Coal (open access)

Fireside Corrosion in Oxy-Fuel Combustion of Coal

The goal is to develop technologies for pulverized coal boilers with >90% CO{sub 2} capture and sequestration and <35% increase in the cost of electricity. Air-fired power plant experience shows a corrosion loss max at 680-700 C. Low melting point alkali metal trisulfates, such as (K,Na){sub 3}Fe(SO{sub 4}){sub 3}, become thermally unstable above this temperature range. Some overall conclusions are: (1) CO{sub 2} + 30% H{sub 2}O more corrosive than Ar + 30% H{sub 2}O; (2) Excess O{sub 2} in H{sub 2}O can, in some cases, greatly increase oxidation; (3) Coal ash is generally innocuous without SO{sub 3}3 in gas phase; and (4) Long-term exposures are starting to establish differences between air-firing and oxy-firing conditions.
Date: October 9, 2011
Creator: Holcomb, G. R.; Tylczak, J.; Meier, G. H.; Jung, K.; Mu, N.; Yanar, N. M. et al.
Object Type: Article
System: The UNT Digital Library
COMPUTER MODELING OF HIGH-LEVEL WASTE GLASS TEMPERATURES WITHIN DWPF CANISTERS DURING POURING AND COOL DOWN (open access)

COMPUTER MODELING OF HIGH-LEVEL WASTE GLASS TEMPERATURES WITHIN DWPF CANISTERS DURING POURING AND COOL DOWN

This report describes the results of a computer simulation study to predict the temperature of the glass at any location inside a DWPF canister during pouring and subsequent cooling. These simulations are an integral part of a larger research focus aimed at developing methods to predict, evaluate, and ultimately suppress nepheline formation in HLW glasses. That larger research focus is centered on holistically understanding nepheline formation in HLW glass by exploring the fundamental thermal and chemical driving forces for nepheline crystallization with respect to realistic processing conditions. Through experimental work, the goal is to integrate nepheline crystallization potential in HLW glass with processing capability to ultimately optimize waste loading and throughput while maintaining an acceptable product with respect to durability. The results of this study indicated severe temperature gradients and prolonged temperature dwell times exist throughout different locations in the canister and that the time and temperatures that HLW glass is subjected to during processing is a function of pour rate. The simulations indicate that crystallization driving forces are not uniform throughout the glass volume in a DWPF (or DWPF-like) canister and illustrate the importance of considering overall kinetics (chemical and thermal driving forces) of nepheline formation when developing methods …
Date: October 9, 2011
Creator: Amoroso, J.
Object Type: Report
System: The UNT Digital Library