Showing papers on "Thermal power station published in 2008"

International Steam Tables

Abstract: This book contains steam tables for industrial use that have been calculated using the international standard for the thermodynamic properties of water and steam, the IAPWS-IF97 formulation, and the international standards for transport and other properties. In addition, the complete set of equations of IAPWS-IF97 is presented including all supplementary backward equations adopted by IAPWS between 2001 and 2005 for fast calculations of heat cycles, boilers, and steam turbines. It is the first time that such a steam table contains the following features: A compact disc (CD) providing an interactive electronic steam table for the calculation of all properties used in the book dependent on freely selectable pressures and temperatures. Formulas to calculate from IAPWS-IF97 arbitrary partial derivatives of the eight most important properties; this is very helpful in non-stationary process modelling. Inclusion of the specific enthalpy and enthalpy differences into the uncertainty values of IPWS-IF97 regarding the most important properties. Pressure-temperature diagrams with isolines of all properties contained in the steam tables and further properties. Moreover, a Molier h-s diagram and a T-s diagram are enclosed as full-colour wall charts in A1-format. Written for: Engineers in industry (power-cycle technology, general energy technology, plant technology) and in utilities; scientists in the fields of energy technology, nuclear technology, and nuclear physics (orig.)

Central Receiver System Solar Power Plant Using Molten Salt as Heat Transfer Fluid

Abstract: Of all the technologies being developed for solar thermal power generation, central receiver systems (CRSs) are able to work at the highest temperatures and to achieve higher efficiencies in electricity production. The combination of this concept and the choice of molten salts as the heat transfer fluid, in both the receiver and heat storage, enables solar collection to be decoupled from electricity generation better than water/steam systems, yielding high capacity factors with solar-only or low hybridization ratios. These advantages, along with the benefits of Spanish legislation on solar energy, moved SENER to promote the 17 MW e Solar TRES plant. It will be the first commercial CRS plant with molten-salt storage and will help consolidate this technology for future higher-capacity plants. This paper describes the basic concept developed in this demonstration project, reviewing the experience accumulated in the previous Solar TWO project, and present design innovations, as a consequence of the development work performed by SENER and CIEMAT and of the technical conditions imposed by Spanish legislation on solar thermal power generation.

Life Cycle Environmental Impacts of Electricity Production by Solarthermal Power Plants in Spain

Abstract: The objectives of the analysis reported in this paper are to evaluate the environmental impacts of the electricity produced in a 17 MW solar thermal plant with central tower technology and a 50 MW solar thermal plant with parabolic trough technology, to identify the opportunities to improve the systems in order to reduce their environmental impacts, and to evaluate the environmental impact resulting from compliance with the solar thermal power objectives in Spain. The methodology chosen is the life cycle assessment (LCA), described in the international standard series ISO 14040-43. The functional unit has been defined as the production of 1 kWh of electricity. Energy use needed to construct, operate, and dismantle the power plants is estimated. These results are used to calculate the "energy payback time" of these technologies. Results were around 1 yr for both power plants. Environmental impacts analyzed include the global warming impacts along the whole life cycle of the power plants, which were around 200 g/kWh generated. Finally, the environmental impacts associated with the compliance of the solar thermal power objectives in Spain were computed. Those figures were then used to estimate the avoided environmental impacts including the potential CO 2 emission savings that could equiv./yr.

Process for reducing carbon dioxide emission in a power plant

Abstract: A process for reducing CO2 emission in a power plant, wherein the power plant comprises at least one gas turbine coupled to a heat recovery steam generator unit and the CO2 capture unit comprises an absorber and a regenerator, the process comprising the steps of: (a) introducing hot exhaust gas exiting a gas turbine having a certain elevated pressure into a heat recovery steam generator unit to produce steam and a flue gas stream comprising carbon dioxide; (b) removing carbon dioxide from the flue gas stream comprising carbon dioxide by contacting the flue gas stream with absorbing liquid in an absorber having an elevated operating pressure to obtain absorbing liquid enriched in carbon dioxide and a purified flue gas stream, wherein the settings and/or construction of the gas turbine are adjusted such that the hot exhaust gas exiting the gas turbine has a pressure of at least 40% of the elevated operating pressure of the absorber.

Combined-cycle power plant with exhaust gas recycling and CO2 separation, and method for operating a combined cycle power plant

Abstract: A multipurpose power plant (10) has a gas turbine (11). An exhaust-gas steam generator (16) fits downstream to the gas turbine and releases steam onto a steam turbine (19). An exhaust-gas return (28) returns part of the exhaust gases onto the inlet of the gas turbine as they flow through the exhaust-gas steam generator. A carbon-dioxide (CO2) separator plant (25) separates CO2 contained in a non-returned part of the exhaust gases from that part and releases it at a CO2 outlet. An independent claim is also included for a method for operating a multi-purpose power plant.

Adapting Gas Turbines to Zero Emission Oxy-Fuel Power Plants

Abstract: Future power plants will require some type of carbon capture and storage (CCS) system to mitigate carbon dioxide (CO2 ) emissions. The most promising technologies for CCS are: oxy-fuel (O-F) combustion, pre-combustion capture, and post-combustion capture. This paper discusses the recent work conducted by Siemens Power Generation, Florida Turbine Technologies, Inc. (FTT) and Clean Energy Systems, Inc. (CES) in adapting high temperature gas turbines to use CES’s drive gases in high-efficiency O-F zero emission power plants (ZEPPs). CES’s O-F cycle features high-pressure combustion of fuel with oxygen (O2 ) in the presence of recycled coolant (water, steam or CO2 ) to produce drive gases composed predominantly of steam and CO2 . This cycle provides the unique capability to capture nearly pure CO2 and trace by-products by simple condensation of the steam. An attractive O-F power cycle uses high, intermediate and low pressure turbines (HPT, IPT and LPT, respectively). The HPT may be based on either current commercial or advanced steam turbine technology. Low pressure steam turbine technology is readily applicable to the LPT. To achieve high efficiencies, an IPT is necessary and efficiency increases with inlet temperature. The high-temperature IPT’s necessitate advanced turbine materials and cooling technology. O-F plants have an abundance of water, cool steam ∼200°C (400°F) and CO2 that can be used as cooling fluids within the combustor and IPT systems. For the “First Generation” ZEPP, a General Electric J79 turbine, minus the compressor, to be driven directly by CES’s 170 MWt high-pressure oxy-fuel combustor (gas generator), has been adapted. A modest inlet gas temperature of 760°C (1400°F) was selected to eliminate the need for turbine cooling. The J79 turbine operating on natural gas delivers 32 MWe and incorporates a single-stage free-turbine that generates an additional 11 MWe . When an HPT and an LPT are added, the net output power (accounting for losses) becomes 60 MWe at 30% efficiency based on lower heating value (LHV), including the parasitic loads for O2 separation and compression and for CO2 capture and compression to 151.5 bar (2200 psia). For an inlet temperature of 927°C (1700°F), the nominal value, the net output power is 70 MWe at 34% efficiency (LHV). FTT and CES are evaluating a “Second Generation” IPT with a gas inlet temperature of 1260°C (2300°F). Predicted performance values for these plants incorporating the HPT, IPT and the LPT are: output power of approximately 100–200 MWe with an efficiency of 40 to 45%. The “Third Generation” IPT for 2015+ power plants will be based on the development of very high temperature turbines having an inlet temperature goal of 1760°C (3200°F). Recent DOE/CES studies project such plants will have LHV efficiencies in the 50% range for natural gas and HHV efficiencies near 40% for gasified coal.Copyright © 2008 by Clean Energy Systems, Inc and Siemens Power Generation, Inc.

Efficient design of feedwater heaters network in steam power plants using pinch technology and exergy analysis

Abstract: A design method is presented based on pinch technology and exergy analysis to reduce heat transfer irreversibility of the feedwater heaters network in steam power plants. In order to show the effects of this method, an extensive study was performed on four steam power plants. The results show that applying this method can decrease the fuel consumption and the condenser load. It also increases the boiler, the feedwater heaters network, and the turbine exergetic efficiencies. On the whole, the results show that applying this method, with a target pinch temperature of 3°C, increases the cycle 2nd law efficiency 0.3–1.3% and the fossil fuel consumption decreases about 64 × 106kg annually for 8000 operating hours per year of the studied steam power plants. Copyright © 2007 John Wiley & Sons, Ltd.

Desert Power: The Economics of Solar Thermal Electricity for Europe, North Africa, and the Middle East

Abstract: A climate crisis is inevitable unless developing countries limit carbon emissions from the power sector in the near future. This will happen only if the costs of low carbon power production become competitive with fossil fuel power. We focus on a leading candidate for investment: solar thermal or concentrating solar power (CSP), a commercially available technology that uses direct sunlight and mirrors to boil water and drive conventional steam turbines. Solar thermal power production in North Africa and the Middle East could provide enough power to Europe to meet the needs of 35 million people by 2020. We compute the subsidies needed to bring CSP to financial parity with fossil-fuel alternatives. We conclude that large-scale deployment of CSP is attainable with subsidy levels that are modest, given the planetary stakes. By the end of the program, unsubsidized CSP projects are likely to be competitive with coal- and gas-based power production in Europe. The question is not whether CSP is feasible but whether programs using CSP technology will be operational in time to prevent catastrophic climate change. For such programs to spur the clean energy revolution, efforts to arrange financing should begin right away, with site acquisition and construction to follow within a year.

Performance Trends of an Air-Cooled Steam Condenser Under Windy Conditions

Abstract: Air-cooled steam condensers (ACSCs) are increasingly employed to reject heat in modern power plants. Unfortunately, these cooling systems become less effective under windy conditions and when ambient temperatures are high. A better understanding of the fundamental air flow patterns about and through such ACSCs is essential if their performance is to be improved under these conditions. The present numerical study models the air flow field about and through a particular ACSC. The performance of the fans is modeled with the aid of a novel numerical approach known as the “actuator disc model.” Distorted air flow patterns that significantly reduce fan performance in certain areas and recirculatory flows that entrain hot plume air are found to be the reasons for poor ACSC performance. It is found that the reduction in fan performance is the main reason for the poor ACSC performance while recirculation of hot plume air only reduces performance by a small amount.

Solar thermal power plants

Abstract: A solar thermal power plant is provided comprising a solar collection system and a steam-electric power plant. The solar collection system comprises one or more tube radiation absorbers containing a thermal fluid therewithin, the system being configured to heat the thermal fluid by passing the thermal fluid through the one or more tube radiation absorbers while the absorbers are irradiated with solar radiation. The steam-electric power plant comprises an intermediate-pressure steam turbine, a low-pressure steam turbine, at least one additional steam turbine having an inlet pressure higher than that of the intermediate-pressure steam turbine, and piping containing a working fluid. Each turbine is associated with a heat exchange system adapted to transfer heat from the thermal fluid to the working fluid.

An analysis of a thermal power plant working on a Rankine cycle: A theoretical investigation

Abstract: Today, most of the electricity produced throughout the world is from steam power plants. However, electricity is being produced by some other power generation sources such as hydropower, gas power, bio-gas power, solar cells, etc. One newly devel-oped method of electricity generation is the Magneto hydro dynamic power plant. This paper deals with steam cycles used in power plants. Thermodynamic analysis of the Rankine cycle has been undertaken to enhance the efficiency and reli-ability of steam power plants. The thermodynamic deviations resulting in non-ideal or irreversible func-tioning of various steam power plant components have been identified. A comparative study between the Carnot cycle and Rankine cycle efficiency has been analyzed resulting in the introduction of regen-eration in the Rankine cycle. Factors affecting effi-ciency of the Rankine cycle have been identified and analyzed for improved working of thermal power plants.

Integration of an internet-serving datacenter with a thermal power station and reducing operating costs and emissions of carbon dioxide

Abstract: Methods, systems and apparatus for combining a thermal power plant with at least one data center.

Desalination Using Low-Grade Heat Sources

Abstract: This study evaluated the feasibility of utilizing low-grade heat sources such as solar energy or waste heat from industrial processes for desalination. The premise of the approach is that saline waters can be desalinated by evaporation and condensation of fresh water at near-ambient temperatures at low pressures. Low pressures can be achieved naturally in the head space of water columns of height equal to the local barometric head. By connecting the head space of such a saline water column to that of a distilled water column, and by maintaining the temperature of the former about 15–20°C above that of the latter, fresh water can be evaporated from the saline column and condensed in the distilled water column. In this study, it is proposed to use a sensible heat thermal energy storage (TES) system to heat the head space of the saline water column. The TES can be maintained at the desired temperature using solar energy and/or waste heat from thermal power plants, refrigeration plants, or air conditioning un...

Integrated system and method for steam-assisted gravity drainage (sagd)-heavy oil production to produce super-heated steam without liquid waste discharge

Abstract: A method and system for producing steam for extraction of heavy bitumen including the steps of mixing carbon or hydrocarbon fuel The fuel is crude oil, vacuum residue, asphaltin, petcoke or coal The oxidation gas includes oxygen, oxygen enriched air or air-combustion of the mixture under high pressure and high temperature The fuel is mixed with low quality contaminated water containing organics and inorganics The liquid phase transferred to a gas phase includes steam and carbon dioxide, wherein solids are separated from the gas phase The gas phase is mixed with saturated water to scrub the remaining solids and produce saturated steam The solid rich water is recycled back for combustion The saturated steam super-heated dry steam and gas mixture is send to an enhanced oil recovery facility for injection into an underground reservoir

Solar concentration plant for the production of superheated steam.

Abstract: A solar concentration plant which uses water/steam as a heat-carrying fluid, in any thermodynamic cycle or system for the exploitation of process heat, which is comprised of an evaporation subsystem, where saturated steam is produced under the conditions of pressure of the system, and a superheater subsystem through which the steam reaches the required conditions of pressure and temperature at the turbine inlet, and in which an attemperation system (10) may be incorporated, these being physically separated and interconnected by means of a drum (5) in which the separation of water and steam takes place, and in which a strategic control of the pointing of the field of heliostats (1) towards either of the subsystems (evaporator or superheater) may be carried out, with individual or group pointing of the heliostats, in such a way that they jointly control both the pressure within the drum (5) and the outlet temperature of the superheated steam (11).

Materials challenges in advanced coal conversion technologies

Abstract: Coal is a critical component in the international energy portfolio, used extensively for electricity generation. Coal is also readily converted to liquid fuels and/or hydrogen for the transportation industry. However, energy extracted from coal comes at a large environmental price: coal combustion can produce large quantities of ash and CO2, as well as other pollutants. Advanced technologies can increase the efficiencies and decrease the emissions associated with burning coal and provide an opportunity for CO2 capture and sequestration. However, these advanced technologies increase the severity of plant operating conditions and thus require improved materials that can stand up to the harsh operating environments. The materials challenges offered by advanced coal conversion technologies must be solved in order to make burning coal an economically and environmentally sound choice for producing energy.