Improved refractories for slagging gasifiers in IGCC power systems
Most gasifiers are operated for refining, chemical production, and power generation. They are also considered a possible future source of H2 for future power systems under consideration. A gasifier fulfills these roles by acting as a containment vessel to react carbon-containing raw materials with oxygen and water using fluidized-bed, moving-bed, or entrained-flow systems to produce CO and H2, along with other gaseous by-products including CO2, CH4, SOx, HS, and/or NOx. The gasification process provides the opportunity to produce energy more efficiently and with less environmental impact than more conventional combustion processes. Because of these advantages, gasification is viewed as one of the key processes in the U.S. Department of Energy?s vision of an advanced power system for the 21st Century. However, issues with both the reliability and the economics of gasifier operation will have to be resolved before gasification will be widely adopted by the power industry. Central to both enhanced reliability and economics is the development of materials with longer service lives in gasifier systems that can provide extended periods of continuous, trouble-free gasifier operation. The focus of the Advanced Refractories for Gasification project at the Albany Research Center (ARC) is to develop improved refractory liner materials capable of withstanding the harsh, high-temperature environment created by the gasification reaction. Current generation refractory liners in slagging gasifiers are typically replaced every 3 to 18 months at costs ranging up to $1,000,000 or more, depending upon the size of the gasification vessel. Compounding materials and installation costs are the lost-opportunity costs for the time that the gasifier is off-line for refractory repair/exchange. The goal of this project is to develop new refractory materials or to extend the service life of refractory liner materials currently used to at least 3 years. Post-mortem analyses of refractory brick removed from slagging commercial gasifiers and of laboratory produced refractory materials has indicated that slag corrosion and structural spalling are the primary causes of refractory failure. Historically, refractory materials with chrome oxide content as high as 90 pct have been found necessary to achieve the best refractory service life. To meet project goals, an improved high chrome oxide refractory material containing phosphate additions was developed at ARC, produced commercially, and is undergoing gasifier plant trials. Early laboratory tests on the high chrome oxide material suggested that phosphate additions could double the service life of currently available high chromium oxide refractories, translating into a potential savings of millions of dollars in annual gasifier operating costs, as well a significant increase in gasifier on-line availability. The ARC is also researching the potential of no-chrome/low-chrome oxide refractory materials for use in gasifiers. Some of the driving forces for no-chrome/low-chrome oxide refractories include the high cost and manufacturing difficulties of chrome oxide refractories and the fact that they have not met the performance requirements of commercial gasifiers. Development of no/low chrome oxide refractories is taking place through an examination of historical research, through the evaluation of thermodynamics, and through the evaluation of phase diagram information. This work has been followed by cup tests in the laboratory to evaluate slag/refractory interactions. Preliminary results of plant trials and the results of ARC efforts to develop no-chrome/low chrome refractory materials will be presented.
- Research Organization:
- Albany Research Center (ARC), Albany, OR (United States)
- Sponsoring Organization:
- USDOE - Office of Fossil Energy (FE)
- OSTI ID:
- 899004
- Report Number(s):
- DOE/ARC-2004-036; TRN: US200706%%469
- Resource Relation:
- Conference: 18th Annual Conference on Fossil Energy Materials, Knoxville, TN, June 2-4, 2004
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
24 POWER TRANSMISSION AND DISTRIBUTION
36 MATERIALS SCIENCE
CHROMIUM OXIDES
ENVIRONMENTAL IMPACTS
FLUIDIZED BEDS
GASIFICATION
OPERATING COST
OXIDES
PHASE DIAGRAMS
POWER GENERATION
POWER SYSTEMS
RAW MATERIALS
REFRACTORIES
SERVICE LIFE
THERMODYNAMICS
COAL
ECONOMICS
LINERS
MONITORS
RELIABILITY
START-UP
SYNTHESIS GAS
TEMPERATURE MEASUREMENT
TEMPERATURE MONITORING
THERMOCOUPLES