Biomass efficiency

For the methanol route the solar-to-biomass efficiency of 0.2% is followed by a methanol production efficiency (50%), a DMFC or reformer-PEMFC efficiency of 40%, an electric motor efficiency of 93% and the same power train and driving efficiencies as for the fossil fuel car. 

In order to reach these objectives, a genetic approach would be useful to generate metal-tolerant plants with high biomass efficient for bioextraction (Briat et al. 1999). 

Compare and contrast aerobic and anaerobic organic matter decomposition in terms of energy yield, rate, microbial biomass, efficiency, and end products. 

Biomass whether trees, plants, grasses, algae, or water plants, has a heating value of 15.1 X 10 J/dry t, and is converted in integrated biomass planting, harvesting, and conversion systems to SNG at an overall thermal efficiency of 50%. 

Gross heating value of biomass or methane. Conversion of biomass or methane to another biofuel requires that the process conversion efficiency be used to reduce the potential energy available. These figures do not include additional biomass from dedicated energy plantations. 

Another hydrogenation process utilizes internally generated hydrogen for hydroconversion in a single-stage, noncatalytic, fluidized-bed reactor (41). Biomass is converted in the reactor, which is operated at about 2.1 kPa, 800°C, and residence times of a few minutes with steam-oxygen injection. About 95% carbon conversion is anticipated to produce a medium heat value (MHV) gas which is subjected to the shift reaction, scmbbing, and methanation to form SNG. The cold gas thermal efficiencies are estimated to be about 60%. 

The maximum efficiency with which photosynthesis can occur has been estimated by several methods. The upper limit has been projected to range from about 8 to 15%, depending on the assumptions made ie, the maximum amount of solar energy trapped as chemical energy in the biomass is 8 to 15% of the energy of the incident solar radiation. The rationale in support of this efficiency limitation helps to point out some aspects of biomass production as they relate to energy appHcations. 

For the total integrated biomass production—conversion system, the arithmetic product of the efficiencies of biomass production and conversion is the efficiency of the overall system. An overall conversion efficiency near 45% would thus be produced by integrating the biomass plantation illustrated in Table 30 with a conversion process that operated at an overall efficiency of 50%. Every operation in the series is thus equally important. 

In summary, these second-generation gasifiers offer promise for the future in terms of increased efficiency as weU as for use of other feedstocks, such as biomass. The older, first-generation gasifiers, however, continue to be used. 

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