Microbial Processes Promising Technologies for Developing Countries (1979) / Chapter Skim
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6 Fuel and Energy
6 Fuel and Energy
Pages 107-123
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From page 107... ...
Although there are organisms that yield hydrogen and methanol from organic substrates, much more development work is required to make these processes economically feasible. TABLE 6.1 Characteristics of Fuels from Microbial Processes Approximate Gross Typical Fuel Energy Content Sources Process Considerations Liquids Methanol 10,000 BTU/lb Methane None commercially 23.8 MJ/kg available Ethanol 13,000 BTU/lb Molasses, grains, Requires significant 30.6 MI/kg plans biomass capitalinvestment Gases Methane 24,000 BTU/lb Animal, human, Practical for farm and 55.5 MJ/kg and agricultural community use wastes Hydrogen 61,000 BTU/lb Algae-nutrient None commercially 142 MJ/kg system available 107
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From page 108... ...
The fermentations shown in Figures 6.1 and 6.2 are conducted at atmosphenc pressure. However, for the production of volatile products like ethanol, both rapid fermentations using a vacuum, and Me recycling of microbial cells have significant advantages over older conventional methods.
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From page 109... ...
plus 4 gal fusel oil, 4,800 lb carbon dioxide, 1,000 lb carbon, and 900 lb potash 109 Molasses (blackstrap) 2,400 gal Process water 10,000 gal Sulfuric acid (60° Be)
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From page 110... ...
~r ~ (95%) c E _' ~ ~ C: ~ ~ ~ _ _ 3 ~ r __ - Water ~ r plus 400 lb corn oil, 10 gal fusel oil, 4,800 lb carbon dioxide, 750 lb press cake, and 4,400 lb stock feed (dry residue)
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From page 111... ...
thermocellum in pure cultures for ethanol production or in mixed cultures for the production of biogas from cellulosic wastes. Limitations The accumulation of acetic acid during fermentation limits growth, and since C
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From page 112... ...
Biogas production occurs in marry natural microbial ecosystems such as organic sediments of aquatic systems, marshes and soil, arid in the rumen and large intestine, especially in herbivorous animals. It involves a complex mixture of anaerobic bacteria, which convert up to 90 percent of the combustible energy of the degradable organic matter to methane and carbon dioxide.
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From page 113... ...
. ~ 1 A BRICK WALL B GAS HOLDER C I RON ROD D PULLEY E COWDUNG INLET PIPE F SLURRY EXIT CHANNEL G COWDUNG MIXING TANK H DRYING BED I ANGLE IRON POSTS J GAS OUTLET PIPE K COUNTERPOISE WEIGHTS L GROUND LEVEL M EARTH PLATFORM N GAS MOISTURE EXIT TAP O SLURRY LEVEL P F E RME NTATI ON TAN K Q PLATFORM R LEDGE S G AS COC K Source: National Academy of Sciences.
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From page 114... ...
The percentage of solids and the biodegradability of substrates in the feed are important. With a high proportion of solids, the energy requirements for mixing, which is essential for effective fermentation, may be too high and soluble substances such as ammonia or organic acids may reach toxic concentrations.
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From page 115... ...
But the residue and effluent may also serve as substrates for the growth of algae, which in turn may be an effective substrate for the production of methane gas. Even at the farm or village level, the effective production of methane requires competent management, but this should not be a problem if adequate teaching and extension activities are available.
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From page 116... ...
of the microbial enzyme methanol dehydrogenase has been demonstrated. These materials inhibit methanol utilization without preventing the preceding methane oxidation step.
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From page 117... ...
The use of solar energy to produce fuels as well as biomass directly is, therefore, an inviting technical challenge. All green plants and algae use solar radiation in the reduction of CO2 by water.
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From page 118... ...
TABLE 6.4 Algae Capable of Evolving Hydrogen Scenedesmus obligaus Scenedesmus quadricauda Chlorella vulgaris Chlorella fusca Chlorella autotrophica Chlamydomonas moewasii Chlamydomonas debaryana Chlamydomonas dysosmos Chlamydomonas humicola Chlamydomonas reinhardii Ankistrodesmus brauni Ankistrodesmus stipitatum Dunaliella sp. Chondrus crispus Corallina officinals Ceramium niobium Porphyridium aerugineum Hydrogen production has been demonstrated from cell fractions of algae supplemented with essential enzymes.
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From page 119... ...
Many insoluble metal sulfides can be oxidized to corresponding metal sulfates. The oxidation of elements in pyrite ore can lead to the production of oxidized iron, sulfuric acid, and metal salts of sulfuric acid.
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From page 120... ...
The attractions of leaching over conventional methods include its simplicity of operation, the lower capital requirements for materials, and lower energy costs. Bacterial leaching has also been applied to the recovery of hydrocarbons from oil shale.
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From page 121... ...
1976. Biocon version of agricultural wastes for pollution control and energy conversion.
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From page 122... ...
Bacterzologzical Review 41: 100-180. Bacterial Leaching Guay, P.; Silver, M.; and Torma, A
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From page 123... ...
Ram Bux Singh, Gobar Gas Research Station, Ajitmal, Etawah, Uttar Pradesh, India.
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