Viability-based technologies

Viability-based technologies Direct epifluorescent filter microscopy Membrane laser scanning Fluorescence cytometry Fluorescence flow cytometry... 

For convenience, the technologies are divided into growth-based technologies, viability-based technologies, cellular component or artifact-based technologies, and nucleic acid-based technologies as shown in Table 3. 

The pyrolysis-based technology, in particular, because of the co-products opportunity, has the most favorable economics. An added advantage of biomass as a renewable feedstock is that it is not intermittent, but can be used to produce hydrogen as and when required. With scientific and engineering advancements, biomass can be viewed as a key and economically viable component to a renewable-based hydrogen economy. Economic viability of different types of energy generation processes is summarized in Table 8.1 (Bockris, 1981 Tanisho, 1996 Benemann, 1997). 

The publicly-funded fuel cell research program started in 1985, with the main activities performed at the Energy research Centre ofthe Netherlands (ECN). Between 1985 and 2001, about 100 million was invested by mixed public-private funds in the development of fuel cell and hydrogen energy. The objectives ofthe Dutch fuel cell programs were initially oriented to the application of coal gas in MCFC based systems. The MCFC activities were terminated in 2001, after an evaluation failed to indicate its commercial viability with natural gas. Afterwards, the activities shifted to SOFC and PEM technology for high efficient conversion of natural gas in small-scale decentralised units. 

The economic estimation based on the pilot unit results showed that ammonia contributes 70% to the prime cost of the N20. Using this result and the ammonia price 0.37 kg-1 [191], one can evaluate the N20 price to be 0.53 kg-1. Certainly, this cost far exceeds that of dioxygen. Therefore, for reactions producing inexpensive products, like the oxidation of methane to methanol, the application of N20 cannot be economically sound. However, this modest cost opens great N20 prospects for the preparation of more expensive chemical products. For instance, the theoretical expenditure for N20 in the oxidation of benzene to phenol is 17%, and in the oxidation of phenol to hydroquinone is 4%, of the cost of the target product. The commercial viability of such processes will depend primarily on their technological advantages rather than the cost of nitrous oxide. 

To speed up in the short and medium term the exploitation of the technology, in the last 5 years GVS has carried out several projects to demonstrate the environmental, technical, social and economic viability of processes to dehumidify air based on membrane contactors. 

Ortiz, I., Bringas, E., San Roman, M.F. and Urtiaga, A.M. (2004) Selective separation of zinc and iron from spent pickling solutions by membrane-based solvent extraction Process viability. Separation Science and Technology, 39, 2441. 

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