Showing papers on "Thermal power station published in 1998"

Solar Thermal Power Technology: Present Status and Ideas for the Future

Abstract: This article reviews some recent developments in thermodynamic cycles as well as new and innovative thermal power cycles applicable to solar thermal power

Steam cooled gas turbine system

Abstract: A steam cooled gas turbine system in a combined power plant, constituted such that gas turbine blade cooling steam and combustor tail pipe cooling steam are bled from an outlet of a high pressure turbine, passed through a fuel heater for heat exchange with fuel, sprayed with water to be cooled to predetermined temperatures, and then supplied to cooling areas, whereby the cooling steam supply temperatures can be maintained at predetermined values during partial load operation as well as rated operating to achieve effective cooling.

Process for generating electric energy, steam and carbon dioxide from hydrocarbon feedstock

Abstract: The present invention relates to a process for production of electric energy, steam and carbon dioxide in concentrated form from a hydrocarbon feedstock comprising formation of synthesis gas in an air driven autothermal thermal reactor unit (ATR), heat exchanging the formed synthesis gas and thereby producing steam, treating at least part of the synthesis gas in a CO-shift reactor unit and carbon dioxide separation unit for formation of concentrated carbon dioxide and a lean hydrogen containing gas which combusted in a combined cycle gas turbine for production of electric energy, and where air from said turbine unit is supplied to the ATR unit. The exhaust from the gas turbine is heat exchanged for production of steam which together with steam generated upstream is utilized in a steam turbine for production of substantially CO2-free electric energy. Steam may be fed to the gas turbine for diluting the hydrogen containing gas mixture. The process may also be combined with production of synthesis gas products such as methanol and/or ammonia. Part of the gas from the carbon dioxide removal unit may be utilized in a fuel cell.

Method for removing ammonia and carbon dioxide gases from a steam

Abstract: A method for reducing residual ammonia gas from a steam in a steam condenser. The method includes forming a condensate and a residual gas in a first stage, then forming a condensate curtain in the second stage and passing the residual gas through the condensate curtain prior to exiting the steam condenser. The method may be employed to remove ammonia and carbon dioxide gas from a geothermal steam.

Adaptive control for the steam temperature of thermal power plants

Abstract: An adaptive control system was applied to control the steam temperature of utility boilers. In the control system, an adaptive control strategy is embedded on the DCS controllers in parallel with each conventional PID controllers for the boiler. The authors have successfully implemented the proposed system at Chubu Electric Power's Nishi-Nagoya No.3 unit and Owase-Mita No.l unit for controlling the main and reheat steam temperatures. The control improvement takes the form of reduced magnitude of temperature excursions caused by load changes, especially in the reheated steam temperature.

Shear strength characteristics of some Indian fly ashes

Abstract: Thermal power stations using pulverized coal as fuel produce enormous quantities of ash as waste products of combustion. In India, it is estimated that thermal power plants will produce about 100 million t of flyash per year by the year 2000. Hence the problem of ash disposal is expected to become acute due to the limited space available for ash disposal near most of the power plants. This calls for strategies to encourage and establish technological concepts for bulk utilization of fly ash which should not only be cost-effective but also environment friendly. This paper reports an experimental programme carried out to study the shear strength characteristics of fly ash using direct shear tests under different conditions so as to enable its bulk utilization in geotechnical engineering applications. The results are encouraging due to the low unit weight, good frictional properties, low compressibility and high permeability of fly ash.

High efficiency reformed methanol gas turbine power plants

Abstract: The present invention is a high efficiency reformed methanol (syngas) gas turbine power plant. The invention utilizes a Back Pressure steam Turbine (BPT) to maximize the thermal efficiency and the power output of a reformed methanol gas turbine power generation system. Methanol feed is reformed to syngas (H2 and CO2) prior to combustion in the BPT turbine. The endothermic reforming reaction, and the generation of the significant amount of process steam essential for reforming, recovers most of the useful heat in the gas turbine exhaust gas. The process steam pressure is set by the gas turbine inlet requirements, and can be referred to as low pressure steam. Additional heat in the gas turbine exhaust gas is recovered by generating the system's process steam at an elevated pressure, rather than the required low pressure. This high pressure steam is used to drive a BPT, generating additional power and the discharged low pressure steam from the BPT is used as the process steam for the methanol reformer.

Development of a Hydrogen-Fueled Combustion Turbine Cycle for Power Generation

Abstract: Consideration of a hydrogen based economy is attractive because it allows energy to be transported and stored at high densities and then transformed into useful work in pollution-free turbine or fuel cell conversion systems. Through its New Energy and Industrial Technology Development Organization (NEDO) the Japanese government is sponsoring the World Energy Network (WE-NET) Program. The program is a 28-year global effort to define and implement technologies needed for a hydrogen-based energy system. A critical part of this effort is the development of a hydrogen-fueled combustion turbine system to efficiently convert the chemical energy stored in hydrogen to electricity when the hydrogen is combusted with pure oxygen. The full-scale demonstration will be a greenfield power plant located seaside. Hydrogen will be delivered to the site as a cryogenic liquid, and its cryogenic energy will be used to power an air liquefaction unit to produce pure oxygen. To meet the NEDO plant thermal cycle requirement of a minimum of 70.9 percent, low heating value (LHV), a variety of possible cycle configurations and working fluids have been investigated. This paper reports on the selection of the best cycle (a Rankine cycle), and the two levels of technology needed to support a near-term plant and a long-term plant. The combustion of pure hydrogen with pure hydrogen with pure oxygen results only in steam, thereby allowing for a direct-fired Rankine steam cycle. A near-term plant would require only moderate development to support the design of an advanced high pressure steam turbine and an advanced intermediate pressure steam turbine.

Recovery type steam cooled gas turbine

Abstract: In a recovery type steam cooled gas turbine, dew condensation is prevented when feeding steam in a starting operation of the gas turbine, and penetration of high temperature combustion gas into a steam cooling passage is prevented. Also, residual steam is removed in the stopping operation of the gas turbine. The gas turbine (1) has moving and stationary blade steam cooling passages (4a, 4b). The steam from steam cooling pipes (9, 10) flows through these passages to cool them. The steam after cooling is recovered. In the starting operation of the gas turbine, air from a compressor (2) flows through a valve (15) and a flow rate regulator (7). Also, a portion of the air is subjected to a temperature adjustment in a temperature adjuster (5) and flows through three-way valves (11, 12) to a steam cooling passage (4a, 4b) to be discharged through three-way valves (13, 14) and a flow rate regulator valve (8) to warm the passages (4a, 4b). Also, valves (15, 16) are closed and a valve (17) is opened so that outside air or inert gas from a medium feed source (6) may flow. After the warming up operation in the starting operation, the three-way valves (11 to 14) are switched to allow the steam to flow from the pipes (9, 10) to the passages (4a, 4b) to perform cooling during regular operation. Furthermore, after the stopping operation, it is possible to purge the residual steam within the passages (4a, 4b) with air.

Heat exchanger apparatus using porous material, and ceramic engine provided with supercharger driven by thermal energy recorded from exhaust gas by the same apparatus

Abstract: A heat exchange apparatus has heat exchangers comprising porous material of improved heat exchange efficiency provided in an exhaust passage, and a ceramic engine provided with a supercharger comparing a steam turbine driven by the steam generated in the heat exchanger apparatus. The heat exchange apparatus comprises a high temperature heat exchanger having a steam passage provided in an exhaust gas passage through which an exhaust gas passes whereby steam is heated, and a low temperature heat exchanger provided in the portion of the exhaust gas passage on the downstream side of the high temperature heat exchanger which has a water passage for heating water by the exhaust gas. The ceramic engine has a steam turbine type supercharger provided with a steam turbine driven by the steam from the high temperature heat exchanges, a compressor, and a condenser which separates a fluid discharged from the steam turbine into water and low temperature steam. Pressurized air from the compressor is supplied to the combustion chamber, which presses down a piston to carry out compression work during an intake stroke.

Apparatus and method for extracting heat from contaminated waste steam

Abstract: Disclosed is a contaminated waste steam heat recovery apparatus 10 and method therefore which includes a primary condensing unit 38, a low pressure water washing unit 26, a liquid to liquid heat exchanger 36 and a vent fan 31. Waste gas is ducted from fryer 11 to a de-super-heating chamber 14 wherein superheated steam is converted to saturated steam by spraying water into the steam using spray nozzles 15. The gas is then introduced into a vertically disposed air to liquid heat exchanger 16 and is drafted downward therethrough. As heat is removed from the waste gas, water vapor in the steam condenses and in the process, collects some of the oil and hydrocarbons present. A plurality of condensate trays 19 are disposed below the bottom end of heat exchanger 16 in a cascading fashion to collect hold the condensate in the airflow path such that it will absorb some of the heat still present in the remaining waste gas. An oil outlet 22 is provided at the top of collection basin 22 for drawing off concentrated oil 23. The waste gas is pulled into a low pressure water washer 26 where it is washed by a second set of spray nozzles 15. Waste gas and water are sucked downward through a set of turbulence inducing baffles 28. The remaining waste gas is sucked out though exhaust tube 30, using vent fan 31, and vented to the atmosphere.

Gas turbine power augmentation by the addition of nitrogen and moisture to the fuel gas

Abstract: A method and apparatus for increasing power output and efficiency of gas turbines. Power output is enhanced and NOx emissions are lowered while heat rate penalties are minimized by adding nitrogen or a mixture of nitrogen and water vapor to the gas turbine in conjunction with the use of low pressure steam.

Use of data mining techniques in the performance monitoring and optimisation of a thermal power plant

Abstract: The article describes research currently being carried out by the Control of Power Systems Group at the Queen's University of Belfast into the application of data mining to the performance monitoring and optimisation of the steam generation systems in thermal power plants. This work is being carried out in conjunction with Premier Power plc which owns and operates Ballylumford Power Station near Larne in Northern Ireland; this station consists of 3/spl times/120 MW and 3/spl times/200 MW gas/oil fired generating units, plus 2/spl times/60 MW gas/oil turbines. The main components of a steam generation system consist of an oil/gas fired boiler, a turbine and a condenser. Although the operation of these is conceptually simple, the components are extremely complicated and due to the nature of the processes involved in steam generation, they are prone to degradation and failure. This can lead to a reduction in the thermal efficiency of the plant, increases in plant emissions and the possibility of unscheduled power outages. The aim of the research is twofold: to develop models of the plant over the full range of operating conditions; and to develop and implement a system which will use the models to determine the condition of the plant accurately, and which will be able to make operational suggestions to engineers/operators to rectify any deviations detected. The models are to be created by data mining on the large database of archived plant data which Premier Power has made available to Queen's University.

Gas turbine with solar heated steam injection system

Abstract: The energy generating installation comprises a gas turbine ( 10 ) which is operated by steam injected via a steam line ( 16 ). The outlet ( 18 ) of the gas turbine ( 10 ) is connected with the heat exchanger ( 21 ) of a waste heat boiler ( 19 ). The waste heat boiler ( 19 ) contains a steam drum ( 22 ) connected to a preheater ( 24 ) and a steam generator ( 23 ) of the heat exchanger ( 21 ). According to the invention a solar steam generator ( 36 ) is connected to the steam drum ( 22 ) in a second circuit ( 39 ). The steam produced by the solar steam generator ( 36 ) is heated in a superheater ( 22 ) and then used for steam injection purposes. The energy generating installation offers high flexibility at high efficiency despite the unreliable availability of solar energy.

Combined cycle power plant with gas turbine cooling system

Abstract: A combined cycle power plant comprises a gas turbine system and a steam cycle system having a steam turbine to be driven by the steam generated by the waste heat of the exhaust gas of the gas turbine system, wherein the steam from the steam cycle system flows through a gas turbine cooling system of the gas turbine to cool the gas turbine blades and other elements of the gas turbine system to be cooled and the waste heat of the gas turbine system is effectively collected. The gas turbine cooling system is supplied selectively with bleed air from the compressor of the gas turbine or the steam provided from another steam cycle system in order to ensure a sufficient coolant supply at the time of starting and stopping the plant and during the operation with a partial load.

Steam turbines for ultrasupercritical power plants

Abstract: The ongoing concern about global warming and the resulting agreement between industrialized nations to reduce CO{sub 2} and other green house gases has put renewed emphasis on improving the thermal efficiency of fossil fired power plants. Some of the improvements will be achieved due to increased use of more efficient combined cycle units. At the same time, the steam turbine technology for ultra-super-critical steam conditions has matured over the last 5--10 years such that it presents a viable and attractive option for new power plant construction. The improvement in overall performance of steam turbines for thermal power plants has been brought about largely through two kinds of advancements. The first type of advancement is improvement in mechanical efficiency by reducing aerodynamic and leakage losses as the steam expands through the turbine. The second type of advancement is the improvement in thermodynamic efficiency by increasing the temperature and pressure at which heat is added to the power cycle. The focus of this paper will be predominantly on the later type of efforts to advance the state-of-the-art in steam turbine technology. GE is also employing advanced aerodynamic steam path technology which will significantly contribute to the overall high level of efficiency ofmore » ultra-super-critical power plants.« less

Coal fuel gas turbine system

Abstract: A gas turbine system in which substantially all of the compressed air from the compressor portion (1) of the gas turbine is used to fluidize a bed (20) of solid fuel, such as char, in a pressurized fluidized bed gasifier (20) so as to produce a hot gas. The hot gas flows through a heat recovery steam generator (24) so as to produce steam, which is expanded in a steam turbine (26) so as to produce shaft power. A first portion of the hot gas from the heat recovery steam generator is expanded in the turbine section (36) of the gas turbine so as to produce additional shaft power. A second portion (48) of the hot gas from the heat recovery steam generator (24) is then used to cool (56, 58, 60) the turbine section (36) of the gas turbine, after further cooling and filtering. Since none of the turbine cooling fluid is obtained by bleeding compressed air directly from the compressor, the mass flow of the hot gas flowing through the gasifier, and, therefore, the hot gas it produces is maximized, thereby maximizing steam generation in the heat recovery steam generator.

Steam turbine low-pressure stage cooling method e.g. for power station turbines

Abstract: The invention relates to a method and device for cooling at least one low-pressure stage (4) of a steam turbine (1) comprising a steam admission area (2) and a steam exhaust area (3). The steam turbine (1) is connected to at least one condenser (5) or is configured as a back pressure turbine. Condensate and/or steam from a cooling system (6) is injected as a cooling medium into the low-pressure stage (4) via a dosing device (7). Said condensate and/or steam is injected according to a temperature value which is measured in the low-pressure stage (4) and according to a parameter which is directly or indirectly correlated to the mass flow rate through the low-pressure stage (4). In an advantageous manner, such a method for cooling a low-pressure stage (4) of a steam turbine (1) reduces the exposure of the steam turbine (1) blades to the risk of erosion resulting from the beating of drops and is easier to control than control systems which are only dependent on temperature.

Performance simulation of heat recovery steam generators in a cogeneration system

Abstract: The performance simulation of heat recovery steam generators in a cogeneration system has been investigated to see the effect of pinch and approach points on steam generation and also on temperature profiles across the heat recovery steam generator. The effects of operating conditions on steam production and also on exit gas temperature from the heat recovery steam generator are discussed. Low pinch point results in improved heat recovery steam generator performance due to reduced irreversibilites. The supplementary firing enhances the steam production. © 1998 John Wiley & Sons, Ltd.

Combined cycle power generating plant and method of supplying cooling steam for gas turbine in same

Abstract: A combined cycle power generating plant comprising in combination a gas turbine plant (10) and a steam turbine plant (40), wherein a cooling steam is appropriately controlled in temperature to thereby provide a turbine which can be manufactured with the use of easily available materials. Steam from a medium pressure evaporator (26) is supplied into a cooling steam supply path (14), through which an exhaust gas from a high pressure turbine (41) is supplied to a high temperature portion (11a) of a gas turbine as a cooling steam, to be mixed with the exhaust gas, whereby the cooling steam is lowered in temperature without reduction in the overall efficiency to enable use of a material of degraded heat resisting performance as a material for formation of the gas turbine high temperature portion (11a) which is in contact with a portion being cooled, so that a relatively inexpensive, easily available material can meet design and manufacture requirements.

Method for closed-loop output control of a steam power plant, and a steam power plant

Abstract: The object of the invention is to ensure a fast, economical and reliable power regulation of a steam generating power plant (1) having a turbo set that comprises a steam turbine (2) and a generator (6) and during the operation of which water (W) is injected into or upstream of an overheater heating surface According to the disclosed fast power regulating process of the steam generating power plant (1), the injection rate of water (W) is increased to adjust an additional generator output. In a steam generating power plant (1) which is particularly suitable for carrying out the process, an overheater heating surface, of a steam generator (28) is provided with a water injector (70, 71) connected to a regulating component (82) for regulating the injection rate of water (W) into the overheater heating surface. The regulating component (82) supplies a regulating signal to the water injector, (70, 72), depending on the required additional generator output.

Characteristics of pulverized-coal combustion in CO2-Recovery power plant applied O2/CO2 combustion

Abstract: The system of oxygen/recycled flue gas combustion for the removal of carbon dioxide from pulverized-coal fired power plants, the combustion characteristics of pulverized coal, and the trial designing of a 1 000 MWe pulverized-coal power plant were studied. The flame propagation speed of pulverized-coal cloud was measured in a microgravity combustion chamber at O 2 /CO 2 , O 2 /N 2 and O 2 /Ar atmosphere. NO x and SO 2 emissions from the system were investigated in the industrial scale combustion test facilities. Based on these results and the previous works, the trial designing of a 1 000 MWe pulverized--coal fired power plant applying this combustion system was also studied. As for the heat absorption performance of the boiler furnace, a 3 dimensional numerical analysis was applied to a large utility boiler furnace. It was compared with another promising system CO 2 -recovery, pulverized-coal power plant combined with amine absorption process.