00/00347 Thermodynamic analysis of geothermal power plants with steam turbines

2000 ◽  
Vol 41 (1) ◽  
pp. 36
Author(s):  
Justin Zachary

Several important sources of renewable energy, such as biomass, concentrated solar panels, waste heat, geothermal, or tidal, use different types of turbo-machinery for conversion to electrical power. The diverse nature of the heat sources and their cyclic behavior make the design of the turbo-machinery power generation equipment quite different than that of the steam turbines used in conventional power plants. The high capital cost of these renewable facilities and the limited hours of operation are powerful drivers to increase the turbo-machinery efficiency. The paper reviews the state-of-the-art hardware designs for each application from an engineering, procurement, and construction (EPC) Contractor’s perspective. Specifically for geothermal power, the discussion covers the application of working fluids other than steam, organic fluid, various mixtures of fluids etc. The benefits and limitations of each method are addressed, along with the impact of geothermal source flow and temperature on the cycle efficiency. The paper also covers the special requirements for single- and multiple-stage arrangements for geothermal applications. For concentrated thermal solar either in high-temperature applications, such as the power tower, or in medium-temperature applications, such as the solar troughs collector field, the paper addresses the unique requirements for performance, integration, and fast startup of the turbines, including the impact of various thermal storage options. Since most of the concentrated thermal solar applications are in arid regions, the paper discusses the heat sink selection (air-cooled condenser [ACC], hybrid, Heller tower, etc.) and how it impacts the plant design and performance. In conclusion, the paper deals with practical issues of achieving a balance between the economics of generation and cost of equipment and reliability for renewable power plants.


Author(s):  
Almar Gunnarsson ◽  
Ari Elisson ◽  
Magnus Jonsson ◽  
Runar Unnthorsson

In a geothermal power plant the working fluid used to produce electricity is often wet steam composed of corrosives chemicals. In this situation, more frequent maintenance of the equipment is required. By constructing an overview for maintenance in geothermal power plants and how it can be done with minimum power outages and cost, the geothermal energy can be made more competitive in comparison to other energy resources. This work is constructed as a part of a project, which has the aim of mapping the maintenance management system at the Hellisheiði geothermal power plant in Iceland. The object of the project is to establish Reliability Centered Maintenance (RCM) program for Hellisheiði power plant that can be utilized to establish efficient maintenance management procedures. The focus of this paper is to examine the steam turbines, which have been defined as one of the main subsystems of the power plant at Hellisheiði. A close look will be taken at the maintenance needed for the steam turbines by studying for example which parts break down and how frequently they fail. The local ability of the staff to repair or construct turbine parts on-site is explored. The paper explores how the maintenance and condition monitoring is carried out today and what can be improved in order to reduce cost. The data collected is analyzed using Failure Mode and Effect Analysis (FMEA) in order to get an overview of the system and to help organizing maintenance and condition monitoring of the power plant in the future. Furthermore, the paper presents an overview of currently employed maintenance methods at Hellisheiði power plant, the domestic ability for maintaining and repairing steam turbines and the power plant’s need for repairs. The results show that the need for maintenance of the geothermal steam turbines at Hellisheiði power plant is high and that on-site maintenance and repairs can decrease the cost.


Alloy Digest ◽  
1993 ◽  
Vol 42 (11) ◽  

Abstract AL 29-4C is a highly corrosion resistant alloy with a relatively high strength. This combination allows the use of lighter gage tubes, and has led to its use in the brine heat exchangers of geothermal power plants. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SS-554. Producer or source: Allegheny Ludlum Corporation.


Sign in / Sign up

Export Citation Format

Share Document