A 150Kw Integrated Solar Combined Cycle (ISCC) Power Plant

Author(s):  
Jon W. Teets ◽  
J. Michael Teets

With the soaring price of oil and the global push toward reduction in carbon emissions, renewable energy is treated by many as a solution to the economic and environmental cost of consumption of fossil fuels. With the power plant reviewed in this paper use of Solar and Bio-fuels will be attained. During the day power needs can be met with Solar energy and when that energy supply is not adequate can use bio-fuels or fuel of choice (gaseous or liquid). If there is a need for use only with Solar energy (i.e. peak power demand) can shut down and restart when desired. Due to the size of the unit, start up is not a long labor intensive task and can be accomplished within the hour. The 150 Kw Integrated Solar Combined Cycle (ISCC) power plant is for commercial and residential use. The unit will produce 150 Kw electrical power output to customer with Solar Thermal Energy (STE). Solar Thermal energy is attained from parabolic trough concentrator(s). Working fluid in the STE system is Syltherm 800 (Silicone Heat Transfer Fluid) is acceptable use from –40F to 750 F. This fluid is heated and passes through a heat exchanger to transfer energy to the closed rankine cycle (where the liquid is changed to vapor stage. Steady state analysis performed on the rankine cycle, with ammonia / water mixture (50/50) used NIST standard reference database 23 for the thermodynamic and transport properties REFPROP [1]. A unique feature with the combined cycle unit, is the rankine cycle turbine wheel is directly attached to the power producing gas turbine spool, thus share a common high speed permanent magnet alternator assembly. The core gas turbine engine used in the combined cycle is a two spool, high pressure ratio (11:1) simple cycle microturbine with cycle efficiency of 20%, at 70Kw output electrical power (sea level standard day). The latter is defined as model TMA 70SC. In addition to the gas turbine engine and rankine turbine stage, the combined cycle incorporates a gas turbine waste heat boiler, economizer, condenser and economizer fluid preheater. The combined cycle unit, without thermal energy, will produce 145Kw (sea level standard day) with an electrical output efficiency of 40%. The gas turbine exhaust to atmosphere will be less than 240 F. The ISCC unit power producing spool / rotor will operate at 100% N regardless of gas turbine power demand. Whereas, spool number one will vary with gas turbine power demand. When the available solar thermal energy decreases the gas turbine fuel flow will increase to maintain electrical power, pending day conditions. The ISCC power plant, can be used for main power plants in [stand alone] communities, business, industrial or distributed energy (D.E.). Also, will provide electrical power to the customer at lower rate than traditional power companies.

Author(s):  
Richard P. Johnston

Potential LHV performance of an indirect coal-fired gas turbine-based combined cycle plant is explored and compared to the typical LHV 35–38 % thermal efficiencies achievable with current coal-fired Rankine Cycle power plants. Plant performance with a baseline synchronous speed, single spool 25:1 pressure ratio gas turbine with a Rankine bottoming cycle was developed. A coal-fired High Temperature Advanced Furnace (HITAF) supplying 2000° F. (1093° C.) hot pressurized air for the gas turbine was modeled for the heat source. The HITAF concept along with coal gas for supplemental heating, are two important parts of the clean coal technology program for power plants. [1,2] From this baseline power plant arrangement, different gas turbine engine configurations with two pressure ratios are evaluated. These variations include a dual spool concentric shaft gas turbine, dual spool non-concentric shaft arrangement, intercooler, liquid metal loop re-heater, free power turbine (FPT) and post HITAF duct burner (DB). A dual pressure Heat Recovery Steam Generator (HRSG) with varying steam pressures to fit conditions is used for each engine. A novel steam generating method employing flash tank technology is applied when a water-cooled intercooler is incorporated. A halogenated hydrocarbon working fluid is also evaluated for lower temperature sub-bottoming Rankine cycle equipment. Current technology industrial gas turbine component performance levels are applied to these various engines to produce a range of LHV gross gas turbine thermal efficiency estimates. These estimates range from the lower thirties to over forty percent. Overall LHV combined cycle plant gross thermal efficiencies range from nearly forty to over fifty percent. All arrangements studied would produce significant improvements in thermal efficiency compared to current coal-fired Rankine cycle power plants. Regenerative inter-cooling, free power turbines, and dual-spool non-concentric shaft gas turbine arrangements coupled with post-HITAF duct burners produced the highest gas turbine engine and plant efficiency results. These advanced engine configurations should also produce operational benefits such as easier starting and much improved part power efficiency over the baseline engine arrangement. An inter-turbine liquid metal re-heat loop reduced engine thermal efficiency but did increase plant power output and efficiency for the example studied. Use of halogenated hydrocarbons as a working fluid would add to plant power output, but at the cost of significant additional plant equipment.


2011 ◽  
Vol 133 (05) ◽  
pp. 30-33 ◽  
Author(s):  
Lee S. Langston

This article explores the increasing use of natural gas in different turbine industries and in turn creating an efficient electrical system. All indications are that the aviation market will be good for gas turbine production as airlines and the military replace old equipment and expanding economies such as China and India increase their air travel. Gas turbines now account for some 22% of the electricity produced in the United States and 46% of the electricity generated in the United Kingdom. In spite of this market share, electrical power gas turbines have kept a much lower profile than competing technologies, such as coal-fired thermal plants and nuclear power. Gas turbines are also the primary device behind the modern combined power plant, about the most fuel-efficient technology we have. Mitsubishi Heavy Industries is developing a new J series gas turbine for the combined cycle power plant market that could achieve thermal efficiencies of 61%. The researchers believe that if wind turbines and gas turbines team up, they can create a cleaner, more efficient electrical power system.


2010 ◽  
Vol 132 (12) ◽  
pp. 57-57
Author(s):  
Lee S. Langston

This article presents an overview of gas turbine combined cycle (CCGT) power plants. Modern CCGT power plants are producing electric power as high as half a gigawatt with thermal efficiencies approaching the 60% mark. In a CCGT power plant, the gas turbine is the key player, driving an electrical generator. Heat from the hot gas turbine exhaust is recovered in a heat recovery steam generator, to generate steam, which drives a steam turbine to generate more electrical power. Thus, it is a combined power plant burning one unit of fuel to supply two sources of electrical power. Most of these CCGT plants burn natural gas, which has the lowest carbon content of any other hydrocarbon fuel. Their near 60% thermal efficiencies lower fuel costs by almost half compared to other gas-fired power plants. Their installed capital cost is the lowest in the electric power industry. Moreover, environmental permits, necessary for new plant construction, are much easier to obtain for CCGT power plants.


2013 ◽  
Vol 24 (4) ◽  
pp. 51-62
Author(s):  
Shadreck M. Situmbeko ◽  
Freddie L. Inambao

Solar thermal energy (STE) technology refers to the conversion of solar energy to readily usable energy forms. The most important component of a STE technology is the collectors; these absorb the shorter wavelength solar energy (400-700nm) and convert it into usable, longer wavelength (about 10 times as long) heat energy. Depending on the quality (temperature and intensity) of the resulting thermal energy, further conversions to other energy forms such as electrical power may follow. Currently some high temperature STE technologies for electricity production have attained technical maturity; technologies such as parabolic dish (commercially available), parabolic trough and power tower are only hindered by unfavourable market factors including high maintenance and operating costs. Low temperature STEs have so far been restricted to water and space heating; however, owing to their lower running costs and almost maintenance free operation, although operating at lower efficiencies, may hold a key to future wider usage of solar energy. Low temperature STE conversion technology typically uses flat plate and low concentrating collectors such as parabolic troughs to harness solar energy for conversion to mechanical and/or electrical energy. These collector systems are relatively cheaper, simpler in construction and easier to operate due to the absence of complex solar tracking equipment. Low temperature STEs operate within temperatures ranges below 300oC. This research work is geared towards developing feasible low temperature STE conversion technology for electrical power generation. Preliminary small-scale concept plants have been designed at 500Wp and 10KWp. Mathematical models of the plant systems have been developed and simulated on the EES (Engineering Equation Solver) platform. Fourteen candidate working fluids and three cycle configurations have been analysed with the models. The analyses included a logic model selector through which an optimal conversion cycle configuration and working fluid mix was established. This was followed by detailed plant component modelling; the detailed component model for the solar field was completed and was based on 2-dimensional segmented thermal network, heat transfer and thermo fluid dynamics analyses. Input data such as solar insolation, ambient temperature and wind speed were obtained from the national meteorology databases. Detailed models of the other cycle components are to follow in next stage of the research. This paper presents findings of the system and solar field component.


Author(s):  
Craig S. Turchi ◽  
Nicholas Langle ◽  
Robin Bedilion ◽  
Cara Libby

Concentrating Solar Power (CSP) systems utilize solar thermal energy for the generation of electric power. This attribute makes it relatively easy to integrate CSP systems with fossil-fired power plants. The “solar-augment” of fossil power plants offers a lower cost and lower risk alternative to stand-alone solar plant construction. This study ranked the potential to add solar thermal energy to coal-fired and natural gas combined cycle (NGCC) plants found throughout 16 states in the southeast and southwest United States. Each generating unit was ranked in six categories to create an overall score ranging from Excellent to Not Considered. Separate analysis was performed for parabolic trough and power tower technologies due to the difference in the steam temperatures that each can generate. The study found a potential for over 11 GWe of parabolic trough and over 21 GWe of power tower capacity. Power towers offer more capacity and higher quality integration due to the greater steam temperatures that can be achieved. The best sites were in the sunny southwest, but all states had at least one site that ranked Good for augmentation. Geographic depiction of the results can be accessed via NREL’s Solar Power Prospector at http://maps.nrel.gov/.


Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
Joa˜o Roberto Barbosa ◽  
Luiz Augusto Horta Nogueira ◽  
Electo E. Silva Lora

The operational rules for the electricity markets in Latin America are changing at the same time that the electricity power plants are being subjected to stronger environmental restrictions, fierce competition and free market rules. This is forcing the conventional power plants owners to evaluate the operation of their power plants. Those thermal power plants were built between the 1960’s and the 1990’s. They are old and inefficient, therefore generating expensive electricity and polluting the environment. This study presents the repowering of thermal power plants based on the analysis of three basic concepts: the thermal configuration of the different technological solutions, the costs of the generated electricity and the environmental impact produced by the decrease of the pollutants generated during the electricity production. The case study for the present paper is an Ecuadorian 73 MWe power output steam power plant erected at the end of the 1970’s and has been operating continuously for over 30 years. Six repowering options are studied, focusing the increase of the installed capacity and thermal efficiency on the baseline case. Numerical simulations the seven thermal power plants are evaluated as follows: A. Modified Rankine cycle (73 MWe) with superheating and regeneration, one conventional boiler burning fuel oil and one old steam turbine. B. Fully-fired combined cycle (240 MWe) with two gas turbines burning natural gas, one recuperative boiler and one old steam turbine. C. Fully-fired combined cycle (235 MWe) with one gas turbine burning natural gas, one recuperative boiler and one old steam turbine. D. Fully-fired combined cycle (242 MWe) with one gas turbine burning natural gas, one recuperative boiler and one old steam turbine. The gas turbine has water injection in the combustion chamber. E. Fully-fired combined cycle (242 MWe) with one gas turbine burning natural gas, one recuperative boiler with supplementary burners and one old steam turbine. The gas turbine has steam injection in the combustion chamber. F. Hybrid combined cycle (235 MWe) with one gas turbine burning natural gas, one recuperative boiler with supplementary burners, one old steam boiler burning natural gas and one old steam turbine. G. Hybrid combined cycle (235 MWe) with one gas turbine burning diesel fuel, one recuperative boiler with supplementary burners, one old steam boiler burning fuel oil and one old steam turbine. All the repowering models show higher efficiency when compared with the Rankine cycle [2, 5]. The thermal cycle efficiency is improved from 28% to 50%. The generated electricity costs are reduced to about 50% when the old power plant is converted to a combined cycle one. When a Rankine cycle power plant burning fuel oil is modified to combined cycle burning natural gas, the CO2 specific emissions by kWh are reduced by about 40%. It is concluded that upgrading older thermal power plants is often a cost-effective method for increasing the power output, improving efficiency and reducing emissions [2, 7].


Sign in / Sign up

Export Citation Format

Share Document