CEC Abstracts in PDF format (as of 7/3/07) - CEC-ICMC 2013

CEC 2007 - Abstracts
C3-D-03 Scheme Design and Analysis on the Small-scale
Biogas Liquefaction Cycle
Q.H. Fan, H.Y. Li, Q.S. Yin, L.X. Jia, Institute of
Cryogenics and Superconductivity
TechnologyCHarbin Institute of Technology,
Harbin.
The biogas has important practical significance in solving the energy
crisis as a kind of clean, renewable biological energy of ground. As
the large-scale concentratedness of the biogas is produced, the
liquefaction of the biogas is extremely urgent in technical research in
China. According to the characteristic of the biogas, on the basis of
mature natural gas purification and liquefaction technology, this paper
discussed the small-scale biogas liquefaction system of the double
purposes to purification, liquefaction and recovery of liquefied CO2.
This paper provides the liquefaction biogas plant process chart, and
system analysis, and the effects on the key parameters. Finally, the
thermal parameters of the liquefaction cycle are presented. The result
provides guidelines for the design of the small-scale biogas
liquefaction device.
C3-D-04 Membrane and Joule-Thomson cooler based
natural gas liquefying system
A. Piotrowska, M. Chorowski, Wroclaw University of
Technology.
The significance of liquid natural gas (LNG) as a fuel in transport and
power engineering has increased significantly. The composition of
natural gas is not stable and varies depending on the source. Prior to
its use the gas should be purified, dehydrated, excess nitrogen should
be removed and eventually helium recovered. The combination of the
polymer membrane gas separation technology with Joule –Thomson
closed cycle can be used as a combined purifying and liquefaction
system of natural gas. The impurities can be separated on hollow fiber
membrane and the purified gas can be liquefied with use of Joule-
Thomson cooler supplied with gas mixture. This system is especially
suitable for low capacity natural gas sources. A proper choice of gas
mixture limits temperature difference in the heat exchanger. The paper
presents thermodynamic analysis and optimization of the system.
C3-D-05 Development of a magnetic refrigerator for
hydrogen liquefaction.
S. Yoshioka, H. Nakagome, Chiba University; K.
Kamiya, T. Numazawa, National Institute for
Materials Science; K. Matsumoto, Kanazawa
University.
To prepare for the arrival of the hydrogen society, great effort has
been made on hydrogen liquefaction methods. Compared to
conventional liquefaction systems using a Joule-Thomson valve,
magnetic refrigeration for hydrogen liquefaction has great potential
and its development is an urgent necessity. Magnetic refrigeration
makes use of magnetocaloric effect, and is well known as an efficent
method in principal because its cooling cycle can most closely follow
the Carnot cycle with appropriate heat switches. A liquefaction
principal of our magnetic refrigerator is based on thermo-siphon
method, in which liquid hydrogen is condensed directly on the surface
of magnetic refrigerants and drops downward. This paper reports
recent progress on development of our magnetic refrigerator and ways
to make it more efficient by examing design of magnetic refrigerants.
C3-E Large Scale Systems
C3-E-01 Performance of liquid xenon calorimeter cryogenic
system for the MEG experiment
T. Haruyama, K. Kasami, KEK; H. Nishiguchi, S. Mihara,
T. Mori, W. Otani, R. Sawada, T. Nishitani, The University
of Tokyo.
The rare muon decay physics experiment, so called mu-e-gamma (MEG)
experiment, is almost ready at the Paul Scherer Institute in Zurich. To meet
with extremely high sensitivity to catch gamma-ray, 800L of cryogenic
liquid xenon is used as a main media in the calorimeter. 800 photo
multipliers (PMT) are all immersed in liquid xenon for capturing scintilaton
light in liqud. The total dissipation power of these PMTs is expected to be
about 60 W at 165 K. The scintilation light with a wavelength of 174 nm is
easily absorbed by residual water in the carolimeter, liquid xenon must be
purified to the lebel of ppb water contents. This is achieved by using the
cryogenic centrifugal pump and cold molecular shieves. The total heat load
of the calorimeter is about 120 W, and the single pulse tube cryocooler
compensates this heat load. It has a cooling power of 180 W at 165 K,
developed at KEK and sofisticatedly manufactured at Iwatani Industrial Gas
corp. The cryogenic system mainly consists of a cryocooler, a liquid pump
and a 1000L dewar. In addition to the liquid purification, a pump and a
dewar will be used for an emergency evacuation of large amount of liquid
xenon. The paper describes successful initial performance test of each
cryogenic components and total commissioning.
C3-E-02 Cryogenic Supply for the GERDA Experiment (70m3
LAr Dewar Tank)
Ch. Haberstroh, TU Dresden, Lehrstuhl fuer Kaelte- und
Kryotech.
In the GERDA experiment (GERmanium Detector Array for the search of
neutrinoless double beta decay of 76Ge) germanium diodes are suspended in
a superinsulated copper cryostat filled with liquid argon. The cold medium is
required since the diodes have to be operated at low temperatures,
furthermore for shielding against background radiation. In order to achieve
acceptable radiation levels, a quantity of 70 m³ LAr is needed, placed in a
surrounding water tank. For the same reason the whole experiment will be
placed in the underground laboratories in the Gran Sasso mountains, Italy.
Project leader is the Max-Planck-Institute for Nuclear Physics, Heidelberg.
In order to avoid any detrimental perturbation inside the dewar vessel, the
LAr inventory in the main tank should be kept in subcooled state, at a
working pressure of 1.2 bar absolute at the surface. At the TU Dresden an
appropriate cryogenic arrangement was designed to match with all these
requirements. Liquid nitrogen is used as on-hand cooling medium for a zeroboil-off
system. Special care was taken to cope with the narrow temperature
span between LAr boiling temperature and triple point. In the proposed
solution a subcooler located close to the neck provides a stable LAr
convection inside the main tank. The working pressure is adjusted by a
controlled, slightly elevated temperature level at the liquid – vapor interface.
C3-E-03 The results of cooling test on HTS power cable of
KEPCO
J.H. Lim, S.H. Sohn, S.D. Hwang, Korea Electric Power
Research Institute; H.S. Yang, D.L. Kim, Korea Basic
Science Institute; H.S. Ryoo, Korea Electrotechnology
Research Institute.
Due to the inherent characteristics of the superconductivity allowing large
power transmission capability, many researches on the high temperature
superconductivity (HTS) power cables have been carried out world widely.
KEPCO (Korea Electric Power Corporation) had installed three phases, 22.9
kV, 1250 A, 50 MVA, and 100 m class HTS cable system at Gochang power
test center of KEPCO. The HTS cable system of KEPCO consists of two
terminations, HTS power cable, and cooling system. Decompression cooling
system is chosen for operation characteristics of the HTS cable system
because it has simple structure and is easier to maintain. Sub-cooled liquid
nitrogen is used for coolant of the HTS power cable and operation
temperature of the HTS cable at inlet position is from 66 K to 77 K.
Circulation cooling tests at different temperatures was performed to
investigate operating condition and heat loss at loading AC current was
measured. The results of performance correlated with cooling test will be
presented in this paper.
This work was supported in part by the Electric Power Industry Technology
Evaluation & Planning office, Republic of Korea.
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