Direct sampling of inorganic vapors released during biomass combustion

Conference · Wed Mar 01 04:00:00 EST 1995

OSTI ID:110847

Dayton, D C; Milne, T A ^[1]

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1. National Renewable Energy Lab., Golden, CO (United States)

Alkali metal vapors released during biomass combustion cause significant problems in power generating facilities that convert biomass to electricity. Gas phase transport of alkali vapors increases the potential for fouling and slagging heat transfer surfaces in boilers and will cause accelerated erosion and corrosion of turbine blades in future direct biomass-fired facilities. Biomass power is an attractive renewable energy resource; however, alkali deposits that form on surfaces in power generating facilities reduce the efficiency of electricity production. As a result, there is a need to develop methods or define combustion conditions for reducing the transport of alkali metal containing vapors during biomass combustion. One solution to fouling and slagging problems is to develop methods of hot gas cleanup that reduce the amount of alkali vapor to acceptable levels. This requires a detailed understanding of the mechanisms of alkali metal release during biomass combustion and identification of these alkali metal vapors, how these vapors lead to fouling and slagging, and how they may be sequestered. The authors approach is to sample directly the hot gases liberated from the combustion of small biomass samples in a variable temperature quartz tube reactor employing a molecular beam mass spectrometer (MBMS) system to monitor the combustion event. The authors have successfully used this experimental technique to identify alkali metal containing species released during the combustion of selected biomass feedstocks at four different conditions: 1100{degrees}C in He/O{sub 2}(20%), 800{degrees}C in He/O{sub 2}(20%), 1100{degrees}C in He/O{sub 2}(5%), and 1100{degrees}C in He/O{sub 2}(10%)/Steam(20%). These conditions were chosen to study the effect of temperature, oxygen concentration, and excess steam on alkali metal release and speciation.

• Research Organization: National Renewable Energy Lab., Golden, CO (United States)
• OSTI ID: 110847
• Report Number(s): NREL/CP--433-7748; CONF-9410343--; ON: DE95004052
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
ALKALI METAL COMPOUNDS
BIOMASS
COMBUSTION
FOULING
JETS
MASS SPECTROSCOPY
MOLECULAR BEAMS
SAMPLING