130,358 research outputs found
Process Industry Undergoing Electrification: New Challenges in Functional Safety
No full textThe process industry is transitioning from traditional fuel-fired equipment to electrically powered alternatives, particularly in syngas and hydrogen production, where electrified steam methane reforming (e-SMR) offers a cleaner, more energy-efficient solution. This shift reduces CO2 emissions but introduces new safety challenges, particularly the need to de-energize high-power systems safely during emergencies. Historically, safety systems in SMR relied on mechanical devices like valves to manage hazards. In electrified systems, safely cutting off power is more complex, especially in high-current applications. Conventional approaches, such as using safety relays and contactors, create redundancy but lead to bulky, complex installations in large-scale systems. As part of the EReTech project, a 250 kW e-SMR was constructed, revealing similarities between the control systems of electric motors (inverters) and electrically heated reactors (thyristors). It was found that the Safe Torque Off (STO) function, commonly used in inverters, could provide a reliable and compact method for safely powering off thyristors. Implementing STO for e-SMR systems could significantly simplify installation while enhancing safety, making it a viable solution for large-scale electrification in the chemical industry
Towards sustainable hydrogen production: Integrating electrified and convective steam reformer with carbon capture and storage
No full textThis work reports the design of a process for hydrogen production based on electrified steam methane reforming (e-SMR) coupled with a convective reforming (convective SMR) and carbon capture and storage (CCS) as an alternative to conventional fuel-fired reforming to reduce natural gas (NG) consumption as well as carbon dioxide emissions. The energy required by the reforming reaction is supplied by direct electric heating instead of burning fossil fuel in the radiant section of a furnace, saving 35 % NG and reducing CO2 emission by 29 %. Implementing convective SMR reduces the electric load of the main e-SMR reactor and ensures a slightly higher thermal efficiency (80.2 %) compared to conventional fuel-fired reforming (78.9 %). Further CO2 emissions (85 %) and NG consumption reduction (50 %) are possible by adopting amine-based CO2 capture. If coupled with an energy integration scheme, it is possible to capture 75 % of the CO2 produced, preserving high energy efficiency (79.4 %). This requires only a 14 % increase in capital costs, which is strongly beneficial compared to applying CO2 capture to flue gases of the fuel-fired reforming (69.8 % efficiency and 80 % more capital costs). The process based on e-SMR coupled with convective SMR and CO2 capture ensures a levelized cost of hydrogen (LCOH) of 0.281 € Nm−3 H2, which is much lower than the conventional fuel-fired reforming with CO2 capture applied to flue gases (0.309 € Nm−3 H2). Moreover, it has comparable CO2 emissions (1.59 vs 0.99 kg CO2 emitted kg−1 H2) but produces lower CO2 (6.39 vs 9.88 CO2 produced kg−1 H2) compared to fuel-fired reforming due to using renewable electricity as energy source for the SMR. Compared to conventional fuel-fired reforming, the same process provides similar LCOH (0.283 vs 0.282 € Nm−3 H2) but with drastically lower CO2 emissions (1.59 vs 8.99 kg CO2 emitted kg−1 H2)
Turquoise hydrogen to reduce emissions of the north American oil upstream sector
No full textIn Canadian remote oil sites, natural gas extracted with the bitumen is flared or vented, impacting on the environment. Providing a pipeline network to recover the gas is unaffordable in most cases. Here we propose the economic framework of an innovative process to recover the gas, based on pyrolysis at T=1223K and P = 0.1 MPa, performed in situ. Part of produced hydrogen combusts to sustain the process, while solid carbon is sold. We conceptualised and simulated in Aspen Plus two process alternatives. In configuration 1, the remaining part of hydrogen is sent to a gas turbine, where it burns to produce electricity. In configuration 2, the unburnt hydrogen is purified and sold. Both configurations reduce CO2 emissions by more than 92 % compared to flaring. Both configurations produce a profit over 10 years, being their IRR above 20 % and payback time below 3.5 y
Techno-economic Analysis of Electrified Biogas Reforming
No full textThe world annual hydrogen demand continues to increase with a direct impact on the global CO2 emissions. A potential solution is the production of CO2-neutral hydrogen (green hydrogen) using renewable resources. In addition to electrolytic hydrogen, biogenic hydrogen can increase productivity and enable the expansion of the H2 economy for regions with low availability of solar and wind, such as central Europe. In this work, the design of a decentralized biogas-to-hydrogen process (50 Nm3 h-1 H2 productivity) based on an electrically heated reformer was developed. An economic analysis has established the viability of this suggested production route: the Hydrogen production price remains below 6 € kg-1. It results that this innovative process requires approximately 0.6 Nm3 of biogas and 1.25 kWh of renewable electricity to produce 1 Nm3 of hydrogen
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
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