An ejector is a machine for mixing and transporting fluid under vacuum. Ejectors enhance system efficiency, are easily operated, have a mechanically simple structure, and do not require a power supply. Because of these advantages, ejectors have been used in a variety of industrial fields such as refrigeration systems, power plants, and oil plants. In this work, an ejector was used to safely recycle anode tail gas in a 75 kW molten carbonate fuel cell (MCFC) system at Korea Electric Power Research Institute. In this system, the ejector was placed at the mixing point between the anode tail gas and either the cathode tail gas or fresh air. Because commercial ejectors are not designed for the operating conditions of our fuel cell system, a new ejector was designed for use beyond the operating limits of conventional ejectors. In this study, the entrainment ratio and anode outlet pressure were measured according to the ratio of the nozzle diameter to the throat diameter in the newly designed ejector. These results help to define important criteria of ejectors for MCFC recycling.

1.
Sundmacher
,
K.
,
Kniele
,
A.
,
Pesch
,
H. J.
,
Berndt
,
J. F.
, and
Huppmann
,
G.
, 2007,
Molten Carbonate Fuel Cells
,
Wiley-VCH
,
Weinheim
, pp.
11
14
.
2.
Blomen
,
L. J. M. J.
and
Mugerwa
,
M. N.
, eds., 1993,
Fuel Cell Systems
,
Plenum
,
New York
.
3.
Kim
,
Y. J.
, 2005, “
Studies on the Dynamic Characteristics of CO2 Heat Pump System and Improvement of the System Performance Using an Ejector
,” Ph.D. thesis, Seoul National University Library, Seoul, Korea.
4.
Keenan
,
J. H.
,
Neumann
,
E. P.
, and
Lustwerk
,
F.
, 1950, “
An Investigation of Ejector Design by Analysis and Experiment
,”
ASME J. Appl. Mech.
0021-8936,
17
(
3
), pp.
299
309
.
5.
El-Dessouky
,
H.
,
Ettouney
,
H.
,
Alatiqi
,
I.
, and
Al-Nuwaibit
,
G.
, 2002, “
Evaluation of Steam Jet Ejectors
,”
Chem. Eng. Process.
0255-2701,
41
, pp.
551
561
.
6.
Yapici
,
R.
, and
Ersoy
,
H. K.
, 2005, “
Performance Characteristics of the Ejector Refrigeration System Based on the Constant Area Ejector Flow Model
,”
Energy Convers. Manage.
0196-8904,
46
, pp.
3117
3135
.
7.
Zhu
,
Y.
,
Cai
,
W.
,
Wen
,
C.
, and
Li
,
Y.
, 2007, “
Fuel Ejector Design and Simulation Model for Anodic Recirculation SOFC System
,”
J. Power Sources
0378-7753,
173
, pp.
437
449
.
8.
Kim
,
M.
,
Sohn
,
Y. -J.
,
Cho
,
C. -W.
,
Lee
,
W. -Y.
, and
Kim
,
C. -S.
, 2008, “
Customized Design for the Ejector to Recirculate a Humidified Hydrogen Fuel in a Submarine PEMFC
,”
J. Power Sources
0378-7753,
176
, pp.
529
533
.
9.
Marsano
,
F.
,
Magistri
,
L.
, and
Massardo
,
A. F.
, 2004, “
Ejector Performance Influence on a Solid Oxide Fuel Cell Anodic Recirculation System
,”
J. Power Sources
0378-7753,
129
, pp.
216
228
.
10.
Grillo
,
O.
,
Magistri
,
L.
, and
Massardo
,
A. F.
, 2003, “
Hybrid System for Distributed Power Generation Based on Pressurisation and Heat Recovering of an Exiting 100 kW Molten Carbonate Fuel Cell
,”
J. Power Sources
0378-7753,
115
, pp.
252
267
.
11.
Massardo
,
A. F.
, and
Bosio
,
B.
, 2002, “
Assessment of Molten Carbonate Fuel Cell Models and Integration With Gas Turbine Cycles
,”
Trans. ASME: J. Eng. Gas Turbines Power
0742-4795,
124
, pp.
103
109
.
12.
EG&G Services-Parson Inc., Science Application International Corporation
, 2000,
Fuel Cell Handbook
,
5th ed.
,
U.S. DOE
,
Morgantown, WV
.
13.
Heat Exchange Institute, Inc.
, 2007,
Standards for Steam Jet Vacuum Systems
,
6th ed.
,
Heat Exchange Institute, Inc.
,
Cleveland, OH
.
14.
Sun
,
D. -W.
, and
Eames
,
I. W.
, 1995, “
Recent Developments in the Design Theories and Applications of Ejectors—A Review
,”
J. Inst. Energy
0144-2600,
68
, pp.
65
79
.
15.
Keenan
,
H.
, and
Neumann
,
E. P.
, 1947, “
A Simple Air Ejector
,”
ASME Trans. J. Appl. Mech.
0021-8936,
69
, pp.
A317
A336
.
16.
Munday
,
J. T.
, and
Bagster
,
D. F.
, 1977, “
A New Ejector Theory Applied to Steam Jet Refrigeration
,”
Ind. Eng. Chem. Process Des. Dev.
0196-4305,
16
, pp.
442
449
.
17.
Huang
,
B. J.
,
Chang
,
J. M.
,
Wang
,
C. P.
, and
Petrenko
,
V. A.
, 1999, “
A 1-D Analysis of Ejector Performance
,”
Int. J. Refrig.
0140-7007,
22
, pp.
354
364
.
18.
Eames
,
I. W.
,
Aphornratana
,
S.
, and
Haider
,
H.
, 1995, “
A Theoretical and Experimental Study of a Small-Scale Steam Jet Refrigerator
,”
Int. J. Refrig.
0140-7007,
18
, pp.
378
386
.
19.
Kandakure
,
M. T.
,
Gaikar
,
V. G.
, and
Patwardhan
,
A. W.
, 2005, “
Hydrodynamic Aspects of Ejectors
,”
Chem. Eng. Sci.
0009-2509,
60
, pp.
6391
6402
.
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