Abstract

Single- and double-flash steam power plants are commonly used in the utilization of high enthalpy liquid-dominated geothermal resources. In these plants, the expansion line in the wet steam region results in significant penalties of turbine isentropic efficiency and power output. Accordingly, the “self-superheating” and “interstage heating” plant modifications have been recently proposed in the literature, where the saturated steam at turbine inlet is superheated by using the heat of the geothermal liquid, which is cooled before the flashing process. In this study, the aforementioned and additional new flash steam plant layouts are generated by using a systematic method, called Heatsep, for the optimum design of energy systems. All the thermal connections between consecutive basic plant components are “cut” to let these temperatures vary and in turn generate additional hot and cold streams, which are combined to enhance the overall performance of the system. It is demonstrated that the single-flash plant with self-superheating is simply obtained by cutting two out of five thermal links. In the double-flash plant, the higher number of components allows for a higher number of thermal cuts and heat integration options. Unlike the existing literature, the maximum power output is not constrained by a predefined heat transfer network. The optimization results show that the maximum power output of the novel single- and double-flash steam plants exceeds by 5.5–9.2% and 3.9–7.7% the maximum attainable by the corresponding traditional plants without internal heat integration.

References

References
1.
Bertani
,
R.
,
2016
, “
Geothermal Power Generation in the World 2010–2014 Update Report
,”
Geothermics
,
60
, pp.
31
43
. 10.1016/j.geothermics.2015.11.003
2.
DiPippo
,
R.
,
2016
,
Geothermal Power Plants: Principles, Applications, Case Studies and Environmental Impact
,
Butterworth-Heinemann
,
Oxford, UK
.
3.
Moya
,
P.
, and
DiPippo
,
R.
,
2010
, “
Miravalles Unit 3 Single-Flash Plant, Guanacaste, Costa Rica: Technical and Environmental Performance Assessment
,”
Proceedings of the World Geothermal Congress
,
Bali, Indonesia
,
Apr. 25–29
, pp.
1
6
.
4.
Dagdas
,
A.
,
2007
, “
Performance Analysis and Optimization of Double-Flash Geothermal Power Plants
,”
J. Energ. Resour.
,
129
(
2
), pp.
125
133
. 10.1115/1.2719204
5.
Langella
,
G.
,
Paoletti
,
V.
,
DiPippo
,
R.
,
Amoresano
,
A.
,
Steinunnardóttir
,
K.
, and
Milano
,
M.
,
2017
, “
Krafla Geothermal System, Northeastern Iceland: Performance Assessment of Alternative Plant Configurations
,”
Geothermics
,
69
, pp.
74
92
. 10.1016/j.geothermics.2017.04.001
6.
Jalilinasrabady
,
S.
,
Itoi
,
R.
,
Valdimarsson
,
P.
,
Saevarsdottir
,
G.
, and
Fujii
,
H.
,
2012
, “
Flash Cycle Optimization of Sabalan Geothermal Power Plant Employing Exergy Concept
,”
Geothermics
,
43
, pp.
75
82
. 10.1016/j.geothermics.2012.02.003
7.
Bina
,
S. M.
,
Jalilinasrabady
,
S.
, and
Fujii
,
H.
,
2018
, “
Exergoeconomic Analysis and Optimization of Single and Double Flash Cycles for Sabalan Geothermal Power Plant
,”
Geothermics
,
72
, pp.
74
82
. 10.1016/j.geothermics.2017.10.013
8.
Yousefi
,
H.
,
Roumi
,
S.
,
Ármannsson
,
H.
, and
Noorollahi
,
Y.
,
2019
, “
Cascading Uses of Geothermal Energy for a Sustainable Energy Supply for Meshkinshahr City, Northwest, Iran
,”
Geothermics
,
79
, pp.
152
163
. 10.1016/j.geothermics.2019.01.012
9.
Pambudi
,
N. A.
,
Itoi
,
R.
,
Jalilinasrabady
,
S.
, and
Jaelani
,
K.
,
2014
, “
Exergy Analysis and Optimization of Dieng Single-Flash Geothermal Power Plant
,”
Energ. Convers. Manage.
,
78
, pp.
405
411
. 10.1016/j.enconman.2013.10.073
10.
Pambudi
,
N. A.
,
Itoi
,
R.
,
Jalilinasrabady
,
S.
, and
Jaelani
,
K.
,
2015
, “
Performance Improvement of a Single-Flash Geothermal Power Plant in Dieng, Indonesia, Upon Conversion to a Double-Flash System Using Thermodynamic Analysis
,”
Renew. Energ.
,
80
, pp.
424
431
. 10.1016/j.renene.2015.02.025
11.
Clarke
,
J.
, and
McLeskey
,
J. T.
, Jr.
,
2014
, “
The Constrained Design Space of Double-Flash Geothermal Power Plants
,”
Geothermics
,
51
, pp.
31
37
. 10.1016/j.geothermics.2013.11.002
12.
Zeyghami
,
M.
,
2010
, “
Thermoeconomic Optimization of Geothermal Flash Steam Power Plants
,”
Proceedings of the World Geothermal Congress
,
Bali, Indonesia
,
Apr. 25–29
, pp.
1
8
.
13.
Mathieu-Potvin
,
F.
,
2013
, “
Self-Superheating: A New Paradigm for Geothermal Power Plant Design
,”
Geothermics
,
48
, pp.
16
30
. 10.1016/j.geothermics.2013.03.007
14.
DiPippo
,
R.
, and
Vrane
,
D. R.
,
1991
, “
A Double-Flash Plant With Interstage Reheat: Thermodynamic Analysis and Optimization
,”
Geoth. Res. T.
,
15
, pp.
381
386
.
15.
DiPippo
,
R.
,
2013
, “
Geothermal Double-Flash Plant With Interstage Reheating: An Updated and Expanded Thermal and Exergetic Analysis and Optimization
,”
Geothermics
,
48
, pp.
121
131
. 10.1016/j.geothermics.2013.07.006
16.
Raymond Sarr
,
J.-A.
, and
Mathieu-Potvin
,
F.
,
2015
, “
Improvement of Double-Flash Geothermal Power Plant Design: A Comparison of Six Interstage Heating Processes
,”
Geothermics
,
54
, pp.
82
95
. 10.1016/j.geothermics.2014.12.002
17.
Lazzaretto
,
A.
, and
Toffolo
,
A.
,
2008
, “
A Method to Separate the Problem of Heat Transfer Interactions in the Synthesis of Thermal Systems
,”
Energy
,
33
(
2
), pp.
163
170
. 10.1016/j.energy.2007.07.015
18.
Toffolo
,
A.
,
Lazzaretto
,
A.
, and
Morandin
,
M.
,
2010
, “
The HEATSEP Method for the Synthesis of Thermal Systems: An Application to the S-Graz Cycle
,”
Energy
,
35
(
2
), pp.
976
981
. 10.1016/j.energy.2009.06.030
19.
Toffolo
,
A.
,
Lazzaretto
,
A.
,
Manente
,
G.
, and
Paci
,
M.
,
2014
, “
A Multi-Criteria Approach for the Optimal Selection of Working Fluid and Design Parameters in Organic Rankine Cycle Systems
,”
Appl. Energ.
,
121
, pp.
219
232
. 10.1016/j.apenergy.2014.01.089
20.
Manente
,
G.
,
Da Lio
,
L.
, and
Lazzaretto
,
A.
,
2016
, “
Influence of Axial Turbine Efficiency Maps on the Performance of Subcritical and Supercritical Organic Rankine Cycle Systems
,”
Energy
,
107
, pp.
761
772
. 10.1016/j.energy.2016.04.063
21.
Lazzaretto
,
A.
,
Manente
,
G.
, and
Toffolo
,
A.
,
2018
, “
SYNTHSEP: A General Methodology for the Synthesis of Energy System Configurations Beyond Superstructures
,”
Energy
,
147
, pp.
924
949
. 10.1016/j.energy.2018.01.075
22.
Zarrouk
,
S. J.
, and
Moon
,
H.
,
2014
, “
Efficiency of Geothermal Power Plants: A Worldwide Review
,”
Geothermics
,
51
, pp.
142
153
. 10.1016/j.geothermics.2013.11.001
You do not currently have access to this content.