Performance Analysis of Direct Steam Generation-Central Receiver Systems

2012 ◽  
Author(s):  
Javier Sanz-Bermejo ◽  
José Gonzalez-Aguilar ◽  
Manuel Romero
Keyword(s):  
Power Plants ◽  
Superheated Steam ◽  
System Analysis ◽  
Live Steam ◽  
Saturated Steam ◽  
Steam Generation ◽  
Central Receiver ◽  
Power Block ◽  
Direct Steam ◽  
Solar Field

This work presents a comparative study between direct steam generation central receiver solar power plants working at live steam conditions similar to those found in commercial plants. PS10 and PS20 by Abengoa Solar use a single-receiver, producing saturated steam, whereas Sierra SunTower by e-Solar and Ivanpah Solar Electric Generating System (ISEGS) by BrightSource use dual-receiver technology producing superheated steam. The system analysis includes individual studies for each subsystem: solar field, receiver and Rankine power block; as well as the overall-analysis of a 66.7 MWth plant. PS10 working conditions were analysed with and without intermediate reheat step. It was assumed that Sierra SunTower-configuration has non-reheat turbine and Ivanpah-cycle includes an intermediate reheat step. The reheat process in PS10 configuration was performed using a fraction of live steam coming from the receiver; while for Ivanpah-configuration exhaust steam from high pressure turbine stage was sent back to the superheated steam section of the dual-receiver. These concepts make possible to avoid hybridisation and assure special regimes (such as Spanish feed-in tariff). The analysis of the heliostat field for dual-receiver concepts reveals that the aiming strategy on the absorbers has not relevant influence on optical performances. However, receiver efficiency decreased from 91.9%, working with saturated steam, to 87.86–84.14% working with superheated steam related to operating temperatures and heat exchange surface area. This study reveals that the improvement achieved in the power block under Ivanpah configuration was able to compensate higher thermal losses at the receiver, increasing net power production by 25.5% compared with saturated steam conditions.

Comparative System Performance Analysis of Direct Steam Generation Central Receiver Solar Thermal Power Plants in Megawatt Range

2014 ◽  
Vol 136 (1) ◽  
Author(s):  
Javier Sanz-Bermejo ◽  
Víctor Gallardo-Natividad ◽  
José Gonzalez-Aguilar ◽  
Manuel Romero
Keyword(s):  
Power Plants ◽  
Superheated Steam ◽  
Thermal Power ◽  
Solar Thermal ◽  
Saturated Steam ◽  
Thermal Power Plants ◽  
Steam Generation ◽  
Optical Efficiency ◽  
Solar Thermal Power ◽  
Central Receiver

This work proposes and analyses several integration schemes specially conceived for direct steam generation (DSG) in megawatt (MW) range central receiver solar thermal power plants. It is focused on the optical performance related to the heliostat field and the arrangement of receiver absorbers, and the management of steam within a Rankine cycle in the range between 40–160 bar and 400–550 °C at design point. The solar receiver is composed of one single element for saturated steam systems or two vertically aligned separated units, which correspond to the boiler and the superheater (dual-receiver concept), for superheated steam solar thermal power plants. From a fixed heliostat field obtained after layout optimization for the saturated steam solar plant the heliostat field is divided in two concentric circular trapezoids where each of them independently supplies the solar energy required by the boiler and the superheater for the different steam conditions. It has been observed that the arrangement locating the boiler above the superheater provides a slightly higher optical efficiency of the collector system, formed by the solar field and the receiver, compared with the reverse option with superheater above boiler. Besides, two-zone solar fields provide lower performances than the entire heliostat layout aiming at one absorber (saturation systems). Optical efficiency of two-zone solar fields decreases almost linearly with the increment of superheater heat demand. Concerning the whole solar collector, heliostat field plus receiver, the performance decreases with temperature and almost linearly with the steam pressure. For the intervals of steam pressure and temperature under analysis, solar collector of saturated steam plant achieves an optical efficiency 3.2% points higher than the superheated steam system at 40 bar and 400 °C, and the difference increases up to 9.3% points when compared with superheated system at 160 bar and 550 °C. On the other hand, superheated steam systems at 550 °C and pressure between 60 and 80 bar provide the highest overall efficiency, and it is 2.3% points higher than performance of a saturated steam solar plant at 69 bar. However, if saturated steam cycle integrates an intermediate reheat process, both would provide similar performances. Finally, it has been observed that central receiver systems (CRS) producing saturated steam and superheated steam at 500 °C operating at 40 bar provide similar performances.

Comparative System Analysis of Direct Steam Generation and Synthetic Oil Parabolic Trough Power Plants With Integrated Thermal Storage

2011 ◽  
Author(s):  
Jan Fabian Feldhoff ◽  
Kai Schmitz ◽  
Markus Eck ◽  
Lars Schnatbaum-Laumann ◽  
Doerte Laing ◽  
...  
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
System Analysis ◽  
Storage System ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Synthetic Oil ◽  
Direct Steam ◽  
Oil Plant ◽  
Steam Parameters

Parabolic trough power plants are currently the most commercially applied systems for CSP power generation. To improve their cost-effectiveness, one focus of industry and research is the development of processes with other heat transfer fluids than the currently used synthetic oil. One option is the utilization of water/steam in the solar field, the so-called direct steam generation (DSG). Several previous studies promoted the economic potential of DSG technology [1–3]. Analyses’ results showed that live steam parameters of up to 500°C and 120 bars are most promising and could lead to a reduction of the levelized electricity cost (LEC) of about 11% [4]. However, all of these studies only considered plants without thermal energy storage (TES). Therefore, a system analysis including integrated TES was performed by Flagsol GmbH and DLR together with Solar Millennium AG, Schott CSP GmbH and Senior Bergho¨fer GmbH, all Germany. Two types of plants are analyzed and compared in detail: a power plant with synthetic oil and a DSG power plant. The design of the synthetic oil plant is very similar to the Spanish Andasol plants [5] and includes a molten salt two-tank storage system. The DSG plant has main steam parameters of 500 °C and 112 bars and uses phase change material (PCM) for the latent and molten salt for the sensible part of the TES system. To enable comparability, both plants share the same gross electric turbine capacity of 100 MWel, the same TES capacity of nine hours of full load equivalent and the same solar multiple of the collector field of about two. This paper describes and compares both plants’ design, performance and investment. Based on these results, the LEC are calculated and the DSG plant’s potential is evaluated. One key finding is that with currently proposed DSG storage costs, the LEC of a DSG plant could be higher than those of a synthetic oil plant. When considering a plant without TES on the other hand, the DSG system could reduce the LEC. This underlines the large influence of TES and the still needed effort in the development of a commercial storage system for DSG.

scholarly journals A Direct Steam Generation Solar Power Plant With Integrated Thermal Storage

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Jürgen Birnbaum ◽  
Markus Eck ◽  
Markus Fichtner ◽  
Tobias Hirsch ◽  
Dorothea Lehmann ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Storage System ◽  
Thermal Storage ◽  
Market Potential ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Power Block ◽  
Direct Steam ◽  
Solar Field ◽  
Operating Points

For the future market potential of parabolic trough power plants with direct steam generation (DSG), it is beneficial to integrate a thermal storage system. Heat storage media based on phase change materials offer heat transfer at constant temperatures needed for the evaporation process. Different options for a plant layout are presented and discussed. The interactions between the three subsystems—solar field, power block, and thermal storage—are analyzed, and boundary conditions arising from the thermal storage system are identified. Compared with a system without storage the number of operating points increases significantly since different combinations of storage charge and discharge operations go along with a varying power output of the solar field. It is shown that the large number of theoretical operating points can be reduced to a subset with practical relevance. Depending on the live steam parameters a reheat is necessary within the power block. Compared with parabolic trough fields with a single phase heat transfer medium such as oil, a special heat exchanger configuration is needed for a DSG plant. Different alternatives based on available technologies are presented and evaluated.

scholarly journals Comparative system analysis of direct steam generation and synthetic oil parabolic trough power plants with integrated thermal storage

Solar Energy ◽  
2012 ◽  
Vol 86 (1) ◽  
pp. 520-530 ◽  
Author(s):  
Jan Fabian Feldhoff ◽  
Kai Schmitz ◽  
Markus Eck ◽  
Lars Schnatbaum-Laumann ◽  
Doerte Laing ◽  
...  
Keyword(s):  
Power Plants ◽  
System Analysis ◽  
Thermal Storage ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Synthetic Oil ◽  
Direct Steam

Study of Different Configurations of ISCC Parabolic Trough

2014 ◽  
Author(s):  
Dolores Duran ◽  
Rafael Almanza ◽  
Ivan Martínez
Keyword(s):  
High Pressure ◽  
Power Plants ◽  
Low Pressure ◽  
Pressure Level ◽  
Combined Cycle ◽  
Design Parameters ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Direct Steam ◽  
Solar Field

This work shows the study of different configurations of integrated solar combined cycle (ISCC) parabolic-trough power plant with Direct Steam Generation (DSG). This paper is a sequel of previous works (Duran), but in this case six different configurations are analyzed: two pressure level without reheater (2P), 2P considering the solar field the high pressure economizer of the heat recovery steam generator, 2P considering the solar field the low pressure superheater, two pressure level with reheater (2PR), 2PR considering the solar field the low pressure superheater, 2PR considering the solar field the high pressure economizer. The main objective is to achieve the thermoeconomic optimization (based on Thermodynamic 1st. Law) of the HRSG including the solar field, to determine the optimal design parameters of both systems. It is applied a genetic algorithm (GA) methodology employed in previous works for the optimization of combined cycle power plants. Also, a sensitivity analysis with respect to the variation of solar radiation is done for the configurations that yield better results. As a result it would be obtained the optimal parameters of the HRSG and the optimal solar energy contribution for the configurations analyzed.

scholarly journals Energy and Exergy (2E) Analysis of an Optimized Solar Field of Linear Fresnel Reflectors for a Conceptual Direct Steam Generation Power Plant

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4234
Author(s):  
Eduardo González-Mora ◽  
Ma. Dolores Durán-García
Keyword(s):  
Power Plant ◽  
Solar Irradiance ◽  
Power Plants ◽  
Solar Power ◽  
Thermal Power ◽  
Steam Generation ◽  
Promising Alternative ◽  
Energy And Exergy ◽  
Direct Steam ◽  
Solar Field

Direct steam generation is a promising alternative to conventional heat transfer fluids for solar thermal power plants using linear concentrators because water and steam do not have thermal and chemical stability problems. The novelty of this study, an energy and exergy (2E) analysis, was that it was performed on several configurations of a conceptual direct steam generation solar power plant with optimized Fresnel reflectors in Agua Prieta, Mexico coupled with a regenerative steam Rankine power cycle to quantify their efficiency and establish a reference for future implementation of this technology in concentrated solar power plants in Mexico. The thermal model was assumed to be a 1D steady-state flow and validated against results in the literature. It was then applied directly to a case study to determine the size of the solar field. The design point was the lowest solar irradiance day, and evaluating the solar multiple with the highest solar irradiance, taking care not to oversize the solar field, as suggested for solar plants without energy storage. Comparing the performance of the optimized Fresnel field against the FRESDEMO field of Plataforma Solar de Almería, a considerable decrease in the length of the loop has been demonstrated with a low reduction in thermal efficiency.

Modelling and Control of a Solar-Thermal Parabolic Trough DSG Superheater With Several Parallel Rows and Central Steam Separation

2007 ◽  
Author(s):  
Stephan Koch ◽  
Markus Eck ◽  
Tobias Hirsch
Keyword(s):  
Mass Flow ◽  
Operating Conditions ◽  
Solar Thermal ◽  
Saturated Steam ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Steam Quality ◽  
Control Approach ◽  
Power Block ◽  
Solar Field

In this paper, a solar-thermal parabolic trough power plant with direct steam generation (DSG) is investigated with respect to the controllability of the superheating section in a commercial-scale facility with several parallel collector rows. The plant is operated in recirculation mode which has been proven to provide a good live steam quality under changing operating conditions in single-row systems. In a multiple-row collector field, the separation of the remaining water at the end of the evaporator can be achieved by using one central or several distributed separators. Central separation, which will be investigated in this work, appears to be the superior concept. The article proposes a decentralized adaptive proportional-integral (PI) control approach together with a static output mapping for the control valves at the end of the superheating section. The section is fed by a single saturated steam mass flow which has to be distributed on the parallel superheater rows. Together with the individually controlled injection coolers in each row, the distribution control enables the solar field to provide the power block with a reliable steam temperature in the presence of significant local irradiance and input mass flow transients induced by varying solar intensity during the day and passing clouds.

scholarly journals A METHODOLOGY FOR SIMULATION AND ASSESSMENT OF CONCENTRATED SOLAR POWER PLANTS

2016 ◽  
Vol 15 (1) ◽  
pp. 33
Author(s):  
A. R. Starke ◽  
L. F. L. Lemos ◽  
S. Colle ◽  
R. F. Reinaldo ◽  
J. M. Cardemil ◽  
...  
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Steam Generation ◽  
Concentrated Solar Power ◽  
Power Block ◽  
Receiver System ◽  
Direct Steam ◽  
Fluid Properties ◽  
Solar Power Plants ◽  
Concentrated Solar Power Plants

A thermal analysis of Concentrated Solar Power plants is conducted considering parabolic trough collectors (PTC), linear Fresnel collectors using direct steam generation scheme (LFC-DSG) and central receiver system using both molten nitrate salts (CRS-MNS) direct steam generation (CRS-DSG). The plant capacities were ranged from 50 to 800 MWth and the analysis focuses on the environmental conditions of selected locations in South America. Thus, the study considers a parametric analysis of the main design parameter for different plant scales, in terms of the thermal performance indicators as solar field aperture area, power block rating capacity and plant annual efficiencies. The annual production of the plants is calculated by using the Transient System Simulation program (TRNSYS), which considers a new component library developed for that purpose. This library is based in the open access models developed by the U.S National Renewable Energy Laboratory and currently employed by the System Advisor Model (SAM) program. In addition, a new fluid properties subroutine compatible with TRNSYS codes standards was developed, which uses the freeware CoolProp library. These approaches allowed to modify and create new configurations for CSP plants, e.g. thermal storage for the DSG scheme.

Could biomass-fueled boilers be operated at higher steam temperatures? Part 3: Initial analysis of costs and benefits

TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Superheated Steam ◽  
Black Liquor ◽  
Simulation Software ◽  
Operating Conditions ◽  
Costs And Benefits ◽  
Steam Generation ◽  
Fireside Corrosion ◽  
Corrosion Resistant

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.

scholarly journals Multi-scale modelling of a large scale shell-and-tube latent heat storage system for direct steam generation power plants

2020 ◽  
Author(s):  
Clément Beust ◽  
Erwin Franquet ◽  
Jean-Pierre Bédécarrats ◽  
Pierre Garcia ◽  
Jérôme Pouvreau ◽  
...  
Keyword(s):  
Power Plants ◽  
Large Scale ◽  
Storage System ◽  
Steam Generation ◽  
Latent Heat Storage ◽  
Multi Scale ◽  
Direct Steam ◽  
Scale Modelling ◽  
Shell And Tube ◽  
Generation Power
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