1,686 research outputs found
A Review on CO2 Capture Technologies with Focus on CO2-Enhanced Methane Recovery from Hydrates
Natural gas is considered a helpful transition fuel in order to reduce the greenhouse gas emissions of other conventional power plants burning coal or liquid fossil fuels. Natural Gas Hydrates (NGHs) constitute the largest reservoir of natural gas in the world. Methane contained within the crystalline structure can be replaced by carbon dioxide to enhance gas recovery from hydrates. This technical review presents a techno-economic analysis of the full pathway, which begins with the capture of CO2 from power and process industries and ends with its transportation to a geological sequestration site consisting of clathrate hydrates. Since extracted methane is still rich in CO2, on-site separation is required. Focus is thus placed on membrane-based gas separation technologies widely used for gas purification and CO2 removal from raw natural gas and exhaust gas. Nevertheless, the other carbon capture processes (i.e., oxy-fuel combustion, pre-combustion and post-combustion) are briefly discussed and their carbon capture costs are compared with membrane separation technology. Since a large-scale Carbon Capture and Storage (CCS) facility requires CO2 transportation and storage infrastructure, a technical, cost and safety assessment of CO2 transportation over long distances is carried out. Finally, this paper provides an overview of the storage solutions developed around the world, principally studying the geological NGH formation for CO2 sinks
'Backgating' model including self-heating for low-frequency dispersive effects in III-V FETs
A new approach is proposed which takes into account both traps and thermal phenomena for the modelling of deviations between static and dynamic drain current characteristics in III-V field effect transistors. The model is based on the well-known `backgating' concept and can easily be identified on the basis of conventional static drain current characteristics and small-signal, low-frequency S parameters. Experimental results confirm the accuracy of the proposed mode
On-wafer I/V measurement setup for the characterization of low-frequency dispersion in electron devices
Large-signal dynamic modelling of 111-V FETs
cannot he simply based on DC i/v characteristics, when
accurate performance prediction is needed. In fact,
dispersive phenomena due to self-heating and/or traps
(surface state densities and deep level traps) must be taken
into account since they cause important deviations in the
low-frequency dynamic drain current. Thus, static drain
current characteristics should he replaced with a suitable
model which also accounts for low-frequency dispersive
effects. The research community has proposed different
modelling approaches and quite often a characterisation by
means of pulsed i/v measurement systems has been suggested
as the more appropriate for the identification of lowfrequency
drain current models. In the paper, a new largesignal
measurement setup is presented which is based on
simple low-frequency sinusoidal excitations and it is easily
reproducible with conventional general-purpose lab
instrumentation. Moreover, the proposed setup is adopted in
the paper to extract a hackgating-like model for dispersive
phenomen
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