On- and Off-Design Performance of the Feedwater Heating Combined Cycle

Author(s):  
Na Zhang ◽  
Ruixian Cai

Abstract Feedwater heating combined cycle is one of the CC-repowering means for the conventional PC power station improvement. The preferable characteristics of such combined cycle to be used in China and other developing countries for repowering are its comparably lower investment, less oil/gas consumption, especially its low technical difficulties and easier accomplishment. The concise performance expressions for the existing steam station repowering are derived, and highlight is put to the combined cycle off-design performance study. It is pointed out that there are some problems deserving more attention for the part-load operation. The performances of several different operating scenarios are analyzed, and the better one is recommended based on the comparison.

Author(s):  
E. Tsoutsanis ◽  
Y. G. Li ◽  
P. Pilidis ◽  
M. Newby

Accurate gas turbine performance simulation is a vital aid to the operational and maintenance strategy of thermal plants having gas turbines as their prime mover. Prediction of the part load performance of a gas turbine depends on the quality of the engine’s component maps. Taking into consideration that compressor maps are proprietary information of the manufacturers, several methods have been developed to encounter the above limitation by scaling and adapting component maps. This part of the paper presents a new off-design performance adaptation approach with the use of a novel compressor map generation method and Genetic Algorithms (GA) optimization. A set of coefficients controlling a generic compressor performance map analytically is used in the optimization process for the adaptation of the gas turbine performance model to match available engine test data. The developed method has been tested with off-design performance simulations and applied to a GE LM2500+ aeroderivative gas turbine operating in Manx Electricity Authority’s combined cycle power plant in the Isle of Man. It has been also compared with an earlier off-design performance adaptation approach, and shown some advantages in the performance adaptation.


2021 ◽  
Author(s):  
Silvia Ravelli

Abstract This study takes inspiration from a previous work focused on the simulations of the Willem-Alexander Centrale (WAC) power plant located in Buggenum (the Netherlands), based on integrated gasification combined cycle (IGCC) technology, under both design and off-design conditions. These latter included co-gasification of coal and biomass, in proportions of 30:70, in three different fuel mixtures. Any drop in the energy content of the coal/biomass blend, with respect to 100% coal, translated into a reduction in gas turbine (GT) firing temperature and load, according to the guidelines of WAC testing. Since the model was found to be accurate in comparison with operational data, here attention is drawn to the GT behavior. Hence part load strategies, such as fuel-only turbine inlet temperature (TIT) control and inlet guide vane (IGV) control, were investigated with the aim of maximizing the net electric efficiency (ηel) of the whole plant. This was done for different GT models from leading manufactures on a comparable size, in the range between 190–200 MW. The influence of fuel quality on overall ηel was discussed for three binary blends, over a wide range of lower heating value (LHV), while ensuring a concentration of H2 in the syngas below the limit of 30 vol%. IGV control was found to deliver the highest IGCC ηel combined with the lowest CO2 emission intensity, when compared not only to TIT control but also to turbine exhaust temperature control, which matches the spec for the selected GT engine. Thermoflex® was used to compute mass and energy balances in a steady environment thus neglecting dynamic aspects.


Author(s):  
Leonid Moroz ◽  
Maksym Burlaka ◽  
Tishun Zhang ◽  
Olga Altukhova

Abstract To date variety of supercritical CO2 cycles were proposed by numerous authors. Multiple small-scale tests performed, and a lot of supercritical CO cycle aspects studied. Currently, 3-10 MW-scale test facilities are being built. However, there are still several pieces of SCO2 technology with the Technology Readiness Level (TRL) 3-5 and system modeling is one of them. The system modeling approach shall be sufficiently accurate and flexible, to be able to precisely predict the off-design and part-load operation of the cycle at both supercritical and condensing modes with diverse control strategies. System modeling itself implies the utilization of component models which are often idealized and may not provide a sufficient level of fidelity. Especially for prediction of off-design and part load supercritical CO2 cycle performance with near-critical compressor and transition to condensing modes with lower ambient temperatures, and other aspects of cycle operation under alternating grid demands and ambient conditions. In this study, the concept of a digital twin to predict off-design supercritical CO2 cycle performance is utilized. In particular, with the intent to have sufficient cycle simulation accuracy and flexibility the cycle simulation system with physics-based methods/modules were created for the bottoming 15.5 MW Power Generation Unit (PGU). The heat source for PGU is GE LM6000-PH DLE gas turbine. The PGU is a composite (merged) supercritical CO2 cycle with a high heat recovery rate, its design and the overall scheme are described in detail. The calculation methods utilized at cycle level and components’ level, including loss models with an indication of prediction accuracy, are described. The flowchart of the process of off-design performance estimation and data transfer between the modules as well. The comparison of the results obtained utilizing PGU digital twin with other simplified approaches is performed. The results of the developed digital twin utilization to optimize cycle control strategies and parameters to improve off-design cycle performance are discussed in detail.


2002 ◽  
Vol 124 (3) ◽  
pp. 534-541 ◽  
Author(s):  
Z. R. Khalaf ◽  
B. Basler

This paper presents the O&M experience at the Kalaeloa Cogeneration Plant. Performance issues and other problems related to firing heavy oil in a combustion turbine are presented together with their long-term solutions leading to the current successful operation of the IPP power station in Hawaii, USA.


Author(s):  
T E Chappell

PowerGen's 900 MW combined cycle gas turbine (CCGT) power station at Killingholme achieved full load output over two months before the scheduled date for full commercial load and less than 34 months after the turnkey contract was placed. This paper reviews the development of PowerGen's first CCGT power station, discusses the reasons for the choice of this type of plant and examines early operating experience. The contract strategy, a technical description of the plant, the project programme and the environmental impact of the plant relative to a conventional coal-fired power station are also included.


The Shell-Koppers process for the gasification of coal under pressure, based on the principles of entrained-bed technology, is characterized by: practically complete gasification of virtually all solid fuels; production of a clean gas without by-products; high throughput; high thermal efficiency and efficient heat recovery; environmental acceptability. There are numerous possible future applications for this process. The gas produced (93-98 vol. % hydrogen and carbon monoxide) is suitable for the manufacture of hydrogen or reducing gas and, with further processing, substitute natural gas (s.n.g.). Moreover, the gas can be used for the synthesis of ammonia, methanol and liquid hydrocarbons. Another possible application of this process is as an integral part of a combined-cycle power station featuring both gas and steam turbines. The integration of a Shell-Koppers coal gasifier with a combined-cycle power station will allow of electricity generation at 42-45 % efficiency for a wide range of feed coals. The development programme includes the operation of a 150 t/day gasifier at Deutsche Shell’s Harburg refinery since November 1978 and of a 6 t/day pilot plant a Royal Dutch Shell’s Amsterdam laboratories from December 1976 onwards. Both facilities run very successfully. With hard coal a conversion of 99% is reached while producing a gas with only 1 vol. % CO 2 . The next step will be the construction and operation of one or two 1000 t/day prototype plants which are scheduled for commissioning in 1983-4. Towards the end of the 1980s large commercial units with a capacity of 2500 t/day are contemplated. The economy, especially of these large size units, is very competitive.


Author(s):  
Wolfgang Schemenau ◽  
Ulrich Häuser

In industrial countries as well as in developing countries there is a continuous growth of electricity consumption. The normal way to meet these requirements is the stepwise extension of electricity producing plants. In countries where clean fuel is available at acceptable prices the advantages of combined cycle plants in terms of efficiency and of smooth meeting the requirements can be used. The following essay concentrates on the influences of design criterias and ambient conditions on efficiency, output and plant cost for the type of CCP which is most frequently excecuted. As a result of an optimization an executed plant is described also with regard to lay out, required space and erection time.


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