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[en] This fact sheet explains how Anon, Inc., has developed a novel method of removing photoresist--a light-sensitive material used to produce semiconductor wafers for computers--from the computer manufacturing process at reduced cost and greater efficiency. The new technology is technically superior to existing semiconductor cleaning methods and results in reduced use of hazardous chemicals
[en] A hydrogen production system using VHTR, which was combined with a Sulfur-Iodine (SI) thermochemical cycle, is a good candidate for massive hydrogen production. It is being investigated for Nuclear Hydrogen Development and Demonstration (NHDD) project in Korea Atomic Energy Research Institute. The SI thermo-chemical cycle is a good promise for the economical and eco-friendly hydrogen production. In SI cycle, the decomposition of a sulfuric acid is main concern for the material corrosion and mechanical stress on high temperature and pressure operation condition. KAERI has designed and constructed a small-scale gas loop that included sulfuric acid experimental facilities as a secondary loop. The main objectives of the loop are to monitor and validate the performances of NHDD component such as the Process Heat Exchanger (PHE) and sulfuric acid decomposer. In this paper, we discussed the results of the modeling of the sulfuric acid and sulfur trioxide decomposer using Aspen plus process simulator
[en] The construction work of a small-scale high temperature and high-pressure gas loop has been initiated in the beginning of last year as a series of the nuclear hydrogen production project. The loop consists of a primary loop and a secondary loop. The detail description of a loop is shown in reference 1. A primary loop would provide high temperature nitrogen more than the 950 .deg. C under the 4 MPa pressure environments. The high enthalpy of nitrogen transfers the energy to the sulfur trioxide flowing through the secondary loop at the process heat exchanger (PHE) and the trioxide sulfur is divided into dioxide sulfur and oxygen. The objective of the loop is to provide the high pressure and temperature environment to development of a high performance PHE and the performance test of the material. The primary loop will be constructed until the end of February 2007
[en] The Iodine/Sulfur cycle is considered to be one of the most promising thermochemical cycle for massive hydrogen production. One of the key operation of this process is the sulfuric acid decomposition that requires high temperature (over 800 C). Thus, if the coupling of this thermochemical cycle with high temperature heat delivery (from solar or nuclear source) is envisaged, it is mainly to provide energy during this chemical step. The development of components allowing this chemical step is of main importance and requires today a technological involvement. Indeed, mainly parameters remains uncertain for this key component: - material selection enable to resist to high temperature corrosion and allowing good heat transfer, - selection of the best heat exchanger design to perform this chemical reaction with best efficiency, - selection of best catalyst, - evaluation of mock up design to validate several technological improvements and operating conditions. Therefore CEA has decided to initiate this year the development program for this key component: SO3 decomposer producing SO2 and O2. This paper aims to present this development methodology. (authors)
[en] Hydrogen can be an attractive energy if it can be produced cleanly and in a cost effective manner. Nuclear energy can be used as a source of a high temperature process up to 1000 for a hydrogen production. The sulfur-iodine (SI) cycle is a baseline candidate thermo-chemical process. It consists of the following three chemical reactions which yield a dissociation of water. The decomposition at a high temperature of the sulfuric acid is the most energy-demanding reaction both from fundamental and applied points of views which represents the key reaction of the whole SI cycle. In this paper, a shell-and-catalyst-packed-tube type is selected and its fluidic characteristics are applied to an overall heat transfer coefficient calculation. As a result of the study, the sulfur trioxide decomposers for 300mole/s (200MWth VHTR 40% thermal efficiency) and 60mole/s (40MWth VHTR 40% thermal efficiency) hydrogen production rates are presented and discussed
[en] Highlights: ► SO3 competes for the active sites on the carbonaceous surface and inhibits Hg adsorption. ► SO3 suppresses the activity of its next-nearest-neighbor carbon atom. ► SO3 cannot directly provide the active sites. ► SO3 decreases the unoccupied frontier molecular orbitals of the carbonaceous surface. ► SO3 increases the LUMO–HOMO energy gap of the carbonaceous surface. - Abstract: The effect of SO3 on elemental mercury adsorption on a carbonaceous surface is investigated by the density-functional theory calculations. A nine-fused benzene ring model is employed to represent the carbonaceous surface. The edge atoms on the upper side of the model remain unsaturated to simulate the active sites for reaction. All of the possible approaches in which SO3 is adsorbed on the carbonaceous surface are conducted to evaluate their effects on Hg adsorption. The results indicate that the carbonaceous surface is energetically favorable for SO3 adsorption, which causes that SO3 competes for the active sites on the carbonaceous surface. But adsorption of SO3 decreases the adsorption capacity of the carbonaceous surface for Hg0 since SO3 suppresses the activity of its next-nearest-neighbor carbon atom and negatively affects on the frontier molecular orbitals and LUMO–HOMO energy gap of the carbonaceous surface.
[en] Korea Atomic Energy Research Institute (KAERI) is developing hydrogen production process called thermochemical SI(Sulfur Iodine) cycle utilizing the heat from the High Temperature Gas Cooled Reactor (HTGR) with outlet coolant temperature up to 950 .deg. C, which is considered as an efficient reactor for the hydrogen production. The sulfur trioxide decomposer is one of the key components in SI cycle, because the sulfur trioxide is decomposed into sulfur dioxide and oxygen by a heat transferred from the helium gas. In this paper, the sulfur-trioxide decomposer was simulated with a chemical process simulator. A standard shell-and-tube heat exchanger model in the simulator was chosen for the simulation
[en] The International Maritime Organization (IMO) will administer a new 0.5% global sulfur cap on fuel content from 1 January 2020, lowering from the present 3.5% limit. Seawater SOx (sulfur oxide) scrubbing is especially spray scrubbing and a promising alternative to complying with the IMO regulation. However, the ionization of SO2 (sulfur dioxide) and the H2SO4 (sulfuric acid) formed from SO3 (sulfur trioxide) is proposed to accelerate corrosion of the internal seawater pipe. Apparently, the corrosion of the scrubber seawater piping system occurs in a severe and frequent manner. Hence, in this study, electrochemical measurement and weight loss of carbon steel (used as seawater pipe in most of the ships) in diluted sulfuric acid solution were investigated to determine corrosion rate, corrosion current density, corrosion potential, electrochemical behavior, and impressed-current density. Accordingly, the corrosion rate of carbon steel sheet in various diluted sulfuric acid solutions was observed to be greater than that in natural seawater, thus suggesting the fundamental data to deal with corrosion problems in scrubber seawater pipe
[en] Employing EPR spectroscopy in radiation dosimetry is very promising for medical applications because it is fast, reliable and non-destructive. Aniline-2-sulfonic acid (A2SA) is proposed as a tissue equivalent radiation dosimetric system to be used in medical applications of ionizing radiation. The EPR spectrum is a singlet attributed to the formation of sulfur trioxide anion. The tissue equivalency was studied for A2SA and compared to that of soft tissue response and alanine. It was found that the energy independence of A2SA was started after 0.1 MeV for photons and after 1.5 MeV for electrons and the effective atomic number was evaluated and found to be 10.35.
[en] The Iodine/Sulphur thermochemical cycle is considered to be one of the most promising cycle for massive hydrogen production. One of the key operation of this thermochemical process is the sulfuric acid decomposition that requires high temperature (beyond 800 C degrees). Thus, if the coupling of this thermochemical cycle with high temperature heat delivery (from solar or nuclear source) is foreseen, it is mainly to provide energy during this chemical step. The development of components allowing this chemical step is of major importance and requires today a technological involvement. Indeed, many parameters remain uncertain for this key component: -) material selection resisting to high temperature corrosion and allowing for good heat transfer, -) selection of the optimal heat exchanger design to perform this chemical reaction with best efficiency, -) selection of optimal catalyst, -) evaluation of mock up design to validate several technological points. Cea has initiated a specific development program for this key component, aimed to SO3 decomposition to produce SO2 and O2: the HYPRO project. This paper is recalling the HYPRO pluri-annual development program and then focusing on a preliminary design of the SO3 decomposer, based on tube and shell heat exchanger design that could be coupled with a Helium loop providing 1 MWth. The paper is also presenting some pre-calculations on the compact plate heat exchanger in SiC material. (authors)