Advanced digestion process development for methane production from biomass-waste blends
A series of exploratory anaerobic digestion experiments was performed with a mixed biomass-waste feed to search for digestion configurations that provide improved performance over that of conventional high-rate digestion. The techniques studied were pretreatment of the feed with caustic soda, product gas recycling to the digester, recycling of aerobically treated digester effluent to the digester, two-phase digestion with complete mix acid- and methane-phase reactors, and packed-bed, methane-phase digestion of the effluent from an acid-phase reactor. Ambient-temperature pretreatment of the feed blend with dilute caustic and recycling of the product gas each afforded higher methane yields and volatile solids reduction efficiencies than high-rate digestion alone. It was found that spent caustic could be recycled for fresh feed pretreatment and that neutralization was not necessary before feeding to the digester. Two-phase digestion in the complete-mix reactors gave methane yields and reduction efficiencies about the same as those of high-rate digestion but at much higher loadings and reduced detention times thereby offering significant reductions in equipment size for the same throughputs. The use of a packed-bed anaerobic filter as a methane-phase reactor also showed considerable promise for operation at reduced detention times when the filter effluent was recycled to the filter inlet. Analysis of the data from the experiments conducted to study each advanced digestion technique indicates that an integrated series of unit processes consisting of dilute caustic pretreatment, thermophilic acid-phase digestion, mesophilic complete-mix and packed-bed methane-phase digestion, and limited-aeration aerobic treatment of the methane-phase effluents coupled with recycling should exhibit digestion efficiencies and methane yields near the upper practical limits. (Refs. 32).
- Research Organization:
- Inst. of Gas Technology, 3424 South State St., Chicago, IL 60616
- OSTI ID:
- 5167879
- Journal Information:
- ACS Symp. Ser.; (United States), Vol. 144; Conference: ACS/CSJ Chemical Congress, Honolulu, Hawaii, 2 Apr 1979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
METHANE
BIOSYNTHESIS
ANAEROBIC DIGESTION
BENCH-SCALE EXPERIMENTS
EFFICIENCY
HIGH BTU GAS
MIXING
MUNICIPAL WASTES
PERFORMANCE TESTING
RECYCLING
SEWAGE SLUDGE
SODIUM HYDROXIDES
WATER HYACINTHS
YIELDS
ALKALI METAL COMPOUNDS
ALKANES
AQUATIC ORGANISMS
BIOCONVERSION
DIGESTION
FLUIDS
FUEL GAS
FUELS
GAS FUELS
GASES
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXIDES
MANAGEMENT
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PLANTS
PROCESSING
SEWAGE
SLUDGES
SODIUM COMPOUNDS
SYNTHESIS
TESTING
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
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140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)