Design and Analysis of Electric Power Production Unit for Low Enthalpy Geothermal Reservoir Applications

Authors: Ildar Akhmadullin, Mayank Tyagi

Abstract:

The subject of this paper is the design analysis of a single well power production unit from low enthalpy geothermal resources. A complexity of the project is defined by a low temperature heat source that usually makes such projects economically disadvantageous using the conventional binary power plant approach. A proposed new compact design is numerically analyzed. This paper describes a thermodynamic analysis, a working fluid choice, downhole heat exchanger (DHE) and turbine calculation results. The unit is able to produce 321 kW of electric power from a low enthalpy underground heat source utilizing n-Pentane as a working fluid. A geo-pressured reservoir located in Vermilion Parish, Louisiana, USA is selected as a prototype for the field application. With a brine temperature of 126 , the optimal length of DHE is determined as 304.8 m (1000ft). All units (pipes, turbine, and pumps) are chosen from commercially available parts to bring this project closer to the industry requirements. Numerical calculations are based on petroleum industry standards. The project is sponsored by the Department of Energy of the US.

Keywords: Downhole Heat Exchangers, Geothermal Power Generation, Organic Rankine Cycle, Refrigerants, Working Fluids.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1093319

References:

[1] An MIT-led interdisciplinary panel, "The Future of Geothermal Energy”, 2006.
[2] R. DiPippo, "Geothermal Power Plants: Principles, Applications, Case Studies and Environmental Impact”, Elsevier, 2008.
[3] Z. Wang, M.W. McClure, and R.N. Horne, "A Single-well EGS Configuration Using a Thermosiphon”, Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, CA, 2009.
[4] G. Nalla, G.G Shook, G.L. Mines, and K. Bloomfield, "Parametric Sensitivity Study of Operating and Design Variables in Wellbore Heat Exchangers”, Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, CA, 2004.
[5] Sliwa T., Analysis of a Heat Pump System Based on Borehole Heat Exchangers for a Swimming Pool Complex in Krynica, S-Poland, Geothermal Training Program, Reykjavik, Iceland, 1999.
[6] C. Karla, et al., "High Potential Working Fluids and Cycle Concepts for Next-Generation Binary Organic Rankine Cycle for Enhanced Geothermal Systems”, Proceedings, Thirty Seventh Workshop on Geothermal Reservoir Engineering, Stanford, Ca, 2012.
[7] L. Y. Bronicki, "Organic Rankine Cycle Power Plant, for Waste Heat Recovery", presented at 13th Symposium .on Industrial Applications .of Gas Turbines, BANF, Alberta, Canada, 1999.
[8] R. DiPippo, "Second Law Assessment of Binary Plants for Power Generation from Low-temperature Geothermal Fluids”, Geothermics 33, 565–586.A, 2004.
[9] B. Saleh, G. Koglbauer, M. Wendland, J. Fischer, "Working Fluids for Low-Temperature Organic Rankine Cycles”, Energy, 32, 1210–1221, 2007.
[10] A. Schuster, S. Karellas, R. Aumann, "Efficiency Optimization Potential in Supercritical Organic Rankine Cycles”, Energy 2010, 35, 1033–1039.
[11] H.D. MadhawaHettiarachchia, M. Golubovica, W.M. Woreka, Y.Ikegamib, "Optimum Design Criteria for an Organic Rankine Cycle Using Low- Temperature Geothermal Heat Sources”, Energy 32 1698–1706, 2007.
[12] M. Kanoglu, "Exergy Analysis of Dual-Level Binary Geothermal Power Plant”, Geothermics, 31, 709-724, 2004.
[13] J. Mikielewicz, M. Piwowarski, Kr. Kosowski, "Design Analysis of Turbines for Co-generating Micro-power Plant Working in Accordance with Organic Rankine’s Cycle”, Polish Maritime Research, special issue 2009/S1; pp. 34-38, 10.2478/v10012-008-0042-4.
[14] Bassett L., "Case History Using ESP’s to De-Water Horizontal Wells”, SPE paper 133464, 2004.
[15] Feng Y., Numerical Study of Downhole Heat Exchanger Concept in Geothermal Energy Extraction From saturated and Fractured Reservoirs, PhD Dissertation, LSU, 2012.
[16] P. Welch, P. Boyle, "New Turbines to Enable Efficient Geothermal Power Plants”, GRC Transactions, Vol. 33, 2009.
[17] Moran, M.J., Shapiro, H.N., "Fundamentals of Engineering Thermodynamics”, 5th ed. John Wiley & Sons, New York, USA, pp. 205–212, 2004.
[18] A-A.H. El-Sayed, F. Khalaf, S.M. Ghzaly,”Casing Design Considerations for Horizontal Wells”, SPE 21386, 1991.
[19] Witt, "Air Cooled Condensers”, company catalog 630, 2004.
[20] C.O. Durham, "Analysis of Cameron Parish Geopressured Aquifer”, Magma Gulf Company, Baton Rouge, Louisiana, 1978.
[21] E.D. Coltharp, Subsurface Electrical Centrifugal Pumps, SPE Journal 9982-PA, 1984.