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Ronald Dipippo - One of the best experts on this subject based on the ideXlab platform.
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Chapter 9 – Advanced Geothermal Energy Conversion Systems
Geothermal Power Plants, 2016Co-Authors: Ronald DipippoAbstract:No two geothermal resources are exactly alike and thus energy conversion systems must be chosen and often adapted to suit a particular resource. Some geothermal resources demand more sophisticated energy conversion systems, and this chapter reviews some of the advanced systems for geothermal power generation. Hybrid single-Flash and double-Flash systems are often used to increase the output of a system when expanding the generating capacity becomes possible. Hybrid Flash-binary designs also exist, either through adding a binary cycle to an existing single-Flash Plant or by integrating the two from scratch in the initial design. The concept of a total-flow system arises from a desire to avoid the irreversibilities associated with the Flashing processes needed for either a single- or double-Flash Plant. Other advanced designs look to combine geothermal energy with other energy sources such as fossil and solar energy, or combine both power generation and direct heat usage in a single Plant. In addition, systems for dealing with hypersaline brines are also just starting to be exploited.
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Geothermal double-Flash Plant with interstage reheating: An updated and expanded thermal and exergetic analysis and optimization
Geothermics, 2013Co-Authors: Ronald DipippoAbstract:Abstract The concept of a double-Flash geothermal power Plant with an interstage reheater is updated and extended. The conceptual Plant holds a thermodynamic performance advantage over a conventional double-Flash Plant over the range of reservoir temperatures studied from 220 to 320 °C, with the advantage increasing as the temperature increases. An exergy assessment is performed on the whole Plant with a detailed examination of the reheater. The effect on performance of the terminal temperature difference in the reheater is found to be small. The trend in performance of the new Plant is determined as a function of rising wellhead quality in the event that the reservoir begins to “dry out” yielding higher steam fractions at the wellhead. The potential for silica scaling in the lower-temperature components is examined and found to be of concern. The exact optimized separator and Flash temperatures are compared to the simple rule-of-thumb, the “equal-temperature-split” rule, which turns out to be quite accurate. A conventional double-Flash Plant using a turbine designed to remove moisture after each stage is also examined and found to be theoretically roughly equal to the conceptual Plant in terms of power performance. The extra power that can be generated by a reheat Plant is monetized to compare with the extra cost involved in the more complex Plant relative to a conventional double-Flash Plant. The projected payback is relatively short indicating that the proposed Plant should be both thermodynamically and economically worthwhile on condition that some means of controlling silica precipitation is adopted.
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Las Pailas geothermal binary power Plant, Rincón de la Vieja, Costa Rica: Performance assessment of Plant and alternatives
Geothermics, 2013Co-Authors: Ronald Dipippo, Paul MoyaAbstract:A technical assessment is provided of the 35 MW (net) binary power Plant at the Las Pailas geothermal field, along with three alternative designs including a simple single-Flash Plant and a single-Flash Plant combined with a bottoming binary cycle, both with and without a recuperator. The status and characteristics of the wells, the gathering system, and Plant/well field layout are presented. The best producing well is the northernmost one, PGP-17, close to the Rincon de la Vieja National Park; at a wellhead pressure of 8 bar,a, it produces about 135 kg/s total flow of which about 25 kg/s is steam. The unique design of the 2-unit binary power Plant is discussed in detail. Plant performance is assessed based on the design specifications. Thermal and utilization efficiencies are calculated for the Plant, the power cycle, the major components, as well as for the three alternative designs. Under design conditions, the Las Pailas Plant has a thermal efficiency of 15.1%, a Second Law efficiency of 37.2% based on the incoming exergy of the geofluid, and a Second Law efficiency of 51.2% based on the change in exergy of the geofluid as it passes through the Plant. The results of the acceptance test are presented. The analysis of data for the first 15 months of Plant operation indicates that the average Plant (or capacity) factor was 89.9% and the Plant was available and generating power 91.6% of the time. Among the alternative designs considered, the one with the highest power output for the same geofluid inlet conditions as the actual Plant was a single-Flash Plant optimized for peak power using the existing six production well flow curves. That alternative generated about 9.6 MW-gross more than the gross power of the actual Plant, albeit at a slightly lower utilization efficiency. The highest utilization efficiency was achieved with a single-Flash Plant combined with a bottoming binary Plant, either with or without a recuperator. No attempt was made to estimate the installed costs of the alternatives since no data were available on the actual cost to install the Las Pailas Plant.
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Geothermal Power Plants - Chapter 6 – Double-Flash Steam Power Plants
Geothermal Power Plants, 2012Co-Authors: Ronald DipippoAbstract:This chapter discusses the various process and methodologies involved in the designing of double-Flash steam power Plants. Many aspects of a double-Flash Plant are similar to a single-Flash Plant. The double-Flash steam Plant is an improvement on the single-Flash design as it can produce 15–25% more power output for the same geothermal fluid conditions. The addition of the second-Flash process increases the number of possible arrangements in the double-Flash Plants. The process for the double-Flash Plant is illustrated in a temperature entropy diagram based on the thermodynamics of the conversion process. At the point of analysis, the mass flow through the turbine must be increased because the low-pressure steam from the Flasher is admitted to the steam path, and joins the partially expanded high-pressure steam. The optimization process is more complicated because of the extra degree of freedom in the choice of operating parameters. The potential problems associated with the dissolution of silica from waste brines leaving the power Plants are examined in the chapter. In the matter of water pollution, the waste brine from a double-Flash Plant will carry more highly concentrated contaminants than single-Flash Plants.
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Geothermal Power Plants in Turkey
Geothermal Power Plants, 2012Co-Authors: Ronald DipippoAbstract:All three of Turkey’s operating geothermal power Plants lie in the one area of the country that has high-temperature resources, the Buyuk Menderes Graben in western Anatolia. The first Plant discussed in the chapter is located at the Kizildere resource, which is a liquid-dominated reservoir that was discovered in the 1960s. The various wells and power units of this Plant are described in detail, with maps, technical specifications, diagrams, and photos. The technical details of the two Salavatli binary Plants, Dora I and Dora II, are discussed next. A description of the Germencik double-Flash Plant, the first double-Flash Plant in Turkey, follows. This Plant came online very recently in 2009. The chapter concludes with a discussion of the environmental impact of the Plants, specially the disposal of waste brine at the Kizildere Plant, and a discussion of the current and future state of geothermal power in Turkey.
Chuck Kutscher - One of the best experts on this subject based on the ideXlab platform.
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Small-Scale Geothermal Power Plant Field Verification Projects: Preprint
2001Co-Authors: Chuck KutscherAbstract:In the spring of 2000, the National Renewable Energy Laboratory issued a Request for Proposal for the construction of small-scale (300 kilowatt [kW] to 1 megawatt [MW]) geothermal power Plants in the western United States. Five projects were selected for funding. Of these five, subcontracts have been completed for three, and preliminary design work is being conducted. The three projects currently under contract represent a variety of concepts and locations: a 1-MW evaporatively enhanced, air-cooled binary-cycle Plant in Nevada; a 1-MW water-cooled Kalina-cycle Plant in New Mexico; and a 750-kW low-temperature Flash Plant in Utah. All three also incorporate direct heating: onion dehydration, heating for a fish hatchery, and greenhouse heating, respectively. These projects are expected to begin operation between April 2002 and September 2003. In each case, detailed data on performance and costs will be taken over a 3-year period.
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Small-Scale Geothermal Power Plant Field Verification Projects
TRANSACTIONSGEOTHERMAL RESOURCES, 2001Co-Authors: Chuck KutscherAbstract:In the spring of 2000, the National Renewable Energy Laboratory issued a Request for Proposal for the construction of small-scale (300 kilowatt [kW] to 1 megawatt [MW]) geothermal power Plants in the western United States. Five projects were selected for funding. Of these five, subcontracts have been completed for three, and preliminary design work is being conducted. The three projects currently under contract represent a variety of concepts and locations: a 1-MW evaporatively enhanced, air-cooled binary-cycle Plant in Nevada; a 1-MW water-cooled Kalina-cycle Plant in New Mexico; and a 750-kW low-temperature Flash Plant in Utah. All three also incorporate direct heating: onion dehydration, heating for a fish hatchery, and greenhouse heating, respectively. These projects are expected to begin operation between April 2002 and September 2003. In each case, detailed data on performance and costs will be taken over a 3-year period.
Paul Moya - One of the best experts on this subject based on the ideXlab platform.
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Las Pailas geothermal binary power Plant, Rincón de la Vieja, Costa Rica: Performance assessment of Plant and alternatives
Geothermics, 2013Co-Authors: Ronald Dipippo, Paul MoyaAbstract:A technical assessment is provided of the 35 MW (net) binary power Plant at the Las Pailas geothermal field, along with three alternative designs including a simple single-Flash Plant and a single-Flash Plant combined with a bottoming binary cycle, both with and without a recuperator. The status and characteristics of the wells, the gathering system, and Plant/well field layout are presented. The best producing well is the northernmost one, PGP-17, close to the Rincon de la Vieja National Park; at a wellhead pressure of 8 bar,a, it produces about 135 kg/s total flow of which about 25 kg/s is steam. The unique design of the 2-unit binary power Plant is discussed in detail. Plant performance is assessed based on the design specifications. Thermal and utilization efficiencies are calculated for the Plant, the power cycle, the major components, as well as for the three alternative designs. Under design conditions, the Las Pailas Plant has a thermal efficiency of 15.1%, a Second Law efficiency of 37.2% based on the incoming exergy of the geofluid, and a Second Law efficiency of 51.2% based on the change in exergy of the geofluid as it passes through the Plant. The results of the acceptance test are presented. The analysis of data for the first 15 months of Plant operation indicates that the average Plant (or capacity) factor was 89.9% and the Plant was available and generating power 91.6% of the time. Among the alternative designs considered, the one with the highest power output for the same geofluid inlet conditions as the actual Plant was a single-Flash Plant optimized for peak power using the existing six production well flow curves. That alternative generated about 9.6 MW-gross more than the gross power of the actual Plant, albeit at a slightly lower utilization efficiency. The highest utilization efficiency was achieved with a single-Flash Plant combined with a bottoming binary Plant, either with or without a recuperator. No attempt was made to estimate the installed costs of the alternatives since no data were available on the actual cost to install the Las Pailas Plant.
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MIRAVALLES UNIT 3 SINGLE-Flash Plant, GUANACASTE, COSTA RICA: TECHNICAL AND ENVIRONMENTAL PERFORMANCE ASSESSMENT
2010Co-Authors: Paul Moya, Ronald DipippoAbstract:Since it was first visited by a United Nations scientific delegation in 1963, the Miravalles geothermal field in Costa Rica has developed into one of the most productive and reliable geothermal power complexes in the world. Currently five power units are in operation with a total installed capacity of 163 MW. This paper deals with power Plant Unit 3, the only one that is not owned by the Instituto Costarricense de Electricidad (the Costa Rican Electricity Authority), known by its Spanish acronym ICE. This paper provides a brief summary and overview of the current Miravalles operation including a layout of the field showing the locations of power units, wells, and Satellite No.7 and its gathering and reinjection system pipelines. The type of power units and their installed capacities are given along with some performance data including electrical generation, as well as capacity, load and utilization factors. The history of the development of the single-Flash 27.5 MW Unit 3 which began operating in 2000 is presented. The power Plant occupies its own facility in the area of the field known as Las Mesas, approximately 2.5 km to the northnortheast of Units 1 and 2 at Miravalles. ICE is the owner and operator of the other four Miravalles units, as well as the field developer and steam supplier. However, Unit 3, the first and only Build-Operate-Transfer (BOT) power unit at Miravalles, presented specific problems for ICE which has the obligation to supply the steam to the unit as well as to purchase the energy generated by the unit from its owner and operator Geoenergia de Guanacaste (GdG). The conditions under which the steam must arrive at the fence of the unit are precisely defined in the BOT power purchase agreement (PPA). Since the steam conditions from the producing wells changed over the course of operation, ICE had to undertake certain actions to guarantee that they did not default on that obligation. The unique design aspects of the Plant are presented and discussed. The performance of Unit 3 is given in terms of its thermodynamic design and its actual operating conditions. State diagrams are used to show the processes followed by the steam in the Plant; state-point property tables are given for design and typical operating conditions; actual performance data are analyzed in terms of power generation, parasitic power requirements, utilization efficiency, specific steam consumption, and specific brine consumption. Also examined are how the Plant performance and steam supply conditions have changed over the Plant lifetime, and how ICE has managed the field to meet its contractual requirements.
Costante Invernizzi - One of the best experts on this subject based on the ideXlab platform.
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Potential performance of environmental friendly application of ORC and Flash technology in geothermal power Plants
Energy Procedia, 2017Co-Authors: Davide Bonalumi, Paola Bombarda, Costante InvernizziAbstract:The successful exploitation of geothermal energy for power production relies on to the availability of nearly zero emission and efficient technologies, able to provide flexible operation. It can be realized with the binary cycle technology. It consists of a closed power cycle coupled to a closed geothermal loop, whereby the closed power cycle is generally accomplished by means of an organic Rankine cycle (in a few cases the Kalina cycle has been adopted). The confinement of the geothermal fluid in a closed loop is an important advantage from the environmental point of view: possible pollutants contained in the geothermal fluid are not released into the ambient and are directly reinjected underground. Although a well-established technology in the frame of geothermal applications, the adoption of the binary cycle technology is at the moment typically confined to the exploitation of medium-low temperature liquid geothermal reservoirs, generally between 100-170°C. The important advantages of the binary cycle technology from the environmental point of view suggest nevertheless that it is worthwhile to investigate whether the application range could be extended to higher temperature reservoirs, and up to which extent. Moreover, the paper investigates the effect of an increasing CO2content in the geothermal fluid. The paper compares in a convenient high temperature range of the geothermal source the performance of a properly optimized geothermal ORC Plant, with the performance of a modified Flash Plant, whereby the geothermal steam enters a turbine, and the CO2stream is separated, compressed and finally reinjected. An environmentally friendly working fluid, recently introduced in the market, is considered in the ORC optimization process. The performance comparison will involve the assessment of Plant net power. As far as the calculations are concerned, the geothermal fluid is assumed to be a mixture of water and possibly CO2. The auxiliary power consumption is properly accounted for: beyond cooling auxiliaries, a submersible well pump for the ORC Plant and a gas compressor for the reinjection of the non-condensable gases in the Flash Plant are considered.
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Zero Emission Geothermal Flash Power Plant
Energy Procedia, 2017Co-Authors: Davide Bonalumi, Paola Bombarda, Costante InvernizziAbstract:The successful exploitation of geothermal energy for power production relies on the availability of nearly zero emission and efficient technologies. Two zero emission Flash Plant layouts, with full reinjection of the geothermal fluid (non-condensable gas included), are considered. This paper focusses on the CO2issue, and therefore only the carbon dioxide is considered as non-condensable gas present in the geothermal fluid; the CO2 flow is separated, compressed, and reinjected with the geothermal fluid. Both the reservoir and the power Plant are simulated. A first scheme of Plant presents a conventional layout in which the CO2is separated and compressed after the condenser. The second scheme presents a Plant layout that allows the separation of the CO2at higher pressure with respect to the conventional layout, thus reducing the requested power consumption. The conventional Plant scheme performs always better at higher temperature and at lower concentration of CO2. The new layout results better for low temperature and higher gas content.
Davide Bonalumi - One of the best experts on this subject based on the ideXlab platform.
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Potential performance of environmental friendly application of ORC and Flash technology in geothermal power Plants
Energy Procedia, 2017Co-Authors: Davide Bonalumi, Paola Bombarda, Costante InvernizziAbstract:The successful exploitation of geothermal energy for power production relies on to the availability of nearly zero emission and efficient technologies, able to provide flexible operation. It can be realized with the binary cycle technology. It consists of a closed power cycle coupled to a closed geothermal loop, whereby the closed power cycle is generally accomplished by means of an organic Rankine cycle (in a few cases the Kalina cycle has been adopted). The confinement of the geothermal fluid in a closed loop is an important advantage from the environmental point of view: possible pollutants contained in the geothermal fluid are not released into the ambient and are directly reinjected underground. Although a well-established technology in the frame of geothermal applications, the adoption of the binary cycle technology is at the moment typically confined to the exploitation of medium-low temperature liquid geothermal reservoirs, generally between 100-170°C. The important advantages of the binary cycle technology from the environmental point of view suggest nevertheless that it is worthwhile to investigate whether the application range could be extended to higher temperature reservoirs, and up to which extent. Moreover, the paper investigates the effect of an increasing CO2content in the geothermal fluid. The paper compares in a convenient high temperature range of the geothermal source the performance of a properly optimized geothermal ORC Plant, with the performance of a modified Flash Plant, whereby the geothermal steam enters a turbine, and the CO2stream is separated, compressed and finally reinjected. An environmentally friendly working fluid, recently introduced in the market, is considered in the ORC optimization process. The performance comparison will involve the assessment of Plant net power. As far as the calculations are concerned, the geothermal fluid is assumed to be a mixture of water and possibly CO2. The auxiliary power consumption is properly accounted for: beyond cooling auxiliaries, a submersible well pump for the ORC Plant and a gas compressor for the reinjection of the non-condensable gases in the Flash Plant are considered.
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Zero Emission Geothermal Flash Power Plant
Energy Procedia, 2017Co-Authors: Davide Bonalumi, Paola Bombarda, Costante InvernizziAbstract:The successful exploitation of geothermal energy for power production relies on the availability of nearly zero emission and efficient technologies. Two zero emission Flash Plant layouts, with full reinjection of the geothermal fluid (non-condensable gas included), are considered. This paper focusses on the CO2issue, and therefore only the carbon dioxide is considered as non-condensable gas present in the geothermal fluid; the CO2 flow is separated, compressed, and reinjected with the geothermal fluid. Both the reservoir and the power Plant are simulated. A first scheme of Plant presents a conventional layout in which the CO2is separated and compressed after the condenser. The second scheme presents a Plant layout that allows the separation of the CO2at higher pressure with respect to the conventional layout, thus reducing the requested power consumption. The conventional Plant scheme performs always better at higher temperature and at lower concentration of CO2. The new layout results better for low temperature and higher gas content.