Company News
Hydrogen source could be future energy key
A GRAIN of salt or two may be all that microbial electrolysis cells need to produce hydrogen from wastewater or organic byproducts, without adding carbon dioxide to the atmosphere or using grid electricity, according to Penn State engineers.
“This system could produce
hydrogen anyplace there is wastewater near sea water,” said Bruce E. Logan, Kappe Professor of Environmental Engineering. “It uses no grid electricity and is completely carbon neutral. It is an inexhaustible source of energy.” Microbial electrolysis cells that
produce hydrogen are the basis of this recent work, but previously, to produce hydrogen, the fuel cells required some electrical input. Now, Logan, working with postdoctoral fellow Younggy Kim is using the difference between river water and seawater to add the extra energy needed to produce hydrogen. The results, published in the
Proceedings of the National Academy of Sciences, “show that pure hydrogen gas can efficiently be produced from virtually limitless supplies of seawater
and river water and biodegradable organic matter.” Logan’s cells were between 58 and
64 percent efficient and produced between 0.8 to 1.6 cubic meters of hydrogen for every cubic meter of liquid through the cell each day. The researchers estimated that only about 1 percent of the energy produced in the cell was needed to pump water through the system. The key is reverse electrodialysis or RED that extracts energy from the ionic differences between salt water and fresh water. A RED stack consists of alternating ion exchange membranes with each RED contributing to the electrical output. For RED technology to hydrolyze water — split it into hydrogen and oxygen — requires 1.8 volts, which would in practice require about 25 pairs of membrane sand increase pumping resistance. However, combining RED technology with exoelectrogenic bacteria — bacteria that consume organic material and produce an electric current — reduced the number of RED stacks to five membrane pairs.
Gartner cautions oversupply
SEMICONDUCTOR days of inventory are forecast to plateau in the 3rd Q of 2011 at worrisome levels given current conditions and the likelihood that consumer and business spending will be weaker than expected, according to Gartner who expects the industry to begin an correction in late 2011. “The semiconductor industry
entered the third quarter of 2011 with moderately high levels of inventory,” said Gerald Van Hoy, senior research analyst at Gartner. “The correction comes at a time when ASPs are tracking below trend levels, with overcapacity in the foundry space expected to prolong this weakness,” said Peter Middleton, principal analyst at Gartner. “Excess inventory levels helped buffer the impact of the Japanese earthquake.”
Gartner analysts said the industry
will undergo a moderate inventory correction during the next few quarters, which will lower demand for semiconductor production in the second half of 2011 and early 2012. The proportion of total semiconductor inventory held by OEMs has begun to rise; however, it is still near historic lows, which will help reduce the impact of an order correction on semiconductor vendor sales. Gartner’s conclusions are supported by its Gartner Index of Inventory Semiconductor Supply-chain Tracking (GIISST), which remains at caution levels with days of inventory (DOI) at 1.12 in the third quarter of 2011. An above DOI level of 1.10 indicates inventories are inflated.
Previous work with microbial
electrolysis cells showed that they could produce about 0.3 volts of electricity, but not the 0.414 volts needed to generate hydrogen in these fuel cells. Adding less than 0.2 volts of outside electricity released the hydrogen. Now, by incorporating 11 membranes, five membrane pairs that produce about 0.5 volts, the cells produce hydrogen. “The added voltage that we need is a lot less than the 1.8 volts necessary to hydrolyze water,” said Logan. “Biodegradable liquids and cellulose waste are abundant and with no energy in and hydrogen out we can get rid of wastewater and by-products. This could be an inexhaustible source of energy.”
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Below the 0.95 level indicates
inventories are low, components may be on allocation and double ordering begins. The GIISST assesses “normal” inventory levels throughout the supply chain and compares them with current levels to evaluate industry trends. It gauges the normal inventory level at each stage of production that will allow for a smooth flow of products and management of the production process without inventory shortages or surpluses.
www.euroasiasemiconductor.com Issue IV 2011
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