234 research outputs found
Development of a Novel Reformer for Tar-free Syngas Production
AbstractA novel reformer using highly efficient heat regeneration for tar-free syngas production is developed and its performance demonstrated in a pilot-scale plant using steam gasification. Basic design parameters of the regenerative tar reformer, namely residence time and amount of oxidant are determined based on numerical results. It has been predicted that good performance could be achieved at an operation temperature about 1573K, the residence time exceeding 4sec and an oxidant addition of 12% of the syngas flow rate. The regenerative tar reformer so designed shows stable operation. Over 99% of light and heavy tars are reformed to gas in the case of 11.3% oxygen addition to syngas. Further it is seen that a reduction of oxygen consumption more than 30% compared to a conventional oxidation reformer can be achieved. The formation of a high temperature zone has a strong influence on the tar reforming efficiency
Discovery of the Pigtail Molecular Cloud in the Galactic Center
This paper reports the discovery of a helical molecular cloud in the central
molecular zone (CMZ) of our Galaxy. This "pigtail" molecular cloud appears at
(l, b, V_LSR) ~ (-0.7deg, +0.0deg, -70 to -30 km/s), with a spatial size of ~
(20 pc)^2 and a mass of (2-6) 10^5 solar masses. This is the third helical
gaseous nebula found in the Galactic center region to date. Line intensity
ratios indicate that the pigtail molecular cloud has slightly higher
temperature and/or density than the other normal clouds in the CMZ. We also
found a high-velocity wing emission near the footpoint of this cloud. We
propose a formation model of the pigtail molecular cloud. It might be
associated with a magnetic tube that is twisted and coiled because of the
interaction between clouds in the innermost x_1 orbit and ones in the outermost
x_2 orbit.Comment: 15 pages, 6 figures, accepted for publication in Astrophysical
Journa
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