Simulation of Solarized Combined Cycles: Comparison Between Hybrid Gas Turbine and ISCC Plants

Author(s):  
Giovanna Barigozzi ◽  
Giuseppe Franchini ◽  
Antonio Perdichizzi ◽  
Silvia Ravelli

The present paper investigates two different solarized combined cycle layout configurations. In the first scheme, a solarized gas turbine is coupled to a solar tower. Pressurized air at the compressor exit is sent to the solar tower receiver before entering the gas turbine (GT) combustor. Here, temperature is increased up to the nominal turbine inlet value through natural gas combustion. In the second combined cycle (CC) layout, solar energy is collected by line focusing parabolic trough collectors and used to produce superheated steam in addition to the one generated in the heat recovery boiler. The goal of the paper is to compare the thermodynamic performance of these concentrating solar power (CSP) technologies when working under realistic operating conditions. Commercial software and in-house computer codes were combined together to predict CSP plant performance both on design and off-design conditions. Plant simulations have shown the beneficial effect of introducing solar energy at high temperature in the Joule–Brayton cycle and the drawback in terms of GT performance penalization due to solarization. Results of yearly simulations on a 1 h basis for the two considered plant configurations are presented and discussed. The main thermodynamic parameters such as temperatures, pressure levels, and air and steam flow rates are reported for two representative days.

Author(s):  
G. Barigozzi ◽  
G. Franchini ◽  
A. Perdichizzi ◽  
S. Ravelli

The present paper investigates two different Solarized Combined Cycle layout configurations. In the first scheme, a solarized gas turbine is coupled to a solar tower. Pressurized air at compressor exit is sent to the solar tower receiver before entering the GT combustor. Here temperature is increased up to the nominal turbine inlet value through natural gas combustion. In the second CC layout, solar energy is collected by line focusing parabolic trough collectors and used to produce superheated steam in addition to the one generated in the heat recovery boiler. The goal of the paper is to compare the thermodynamic performance of these CSP technologies when working under realistic operating conditions. Commercial software and in-house computer codes were combined together to predict CSP plant performance both on design and off-design conditions. Plant simulations have shown the beneficial effect of introducing solar energy at high temperature in the Joule-Brayton cycle and the drawback in terms of GT performance penalization due to solarization. Results of yearly simulations on a one hour basis for the two considered plant configurations are presented and discussed. Main thermodynamic parameters such temperatures, pressure levels, air and steam flow rates are reported for two representative days.


Author(s):  
James C. Corman ◽  
Douglas M. Todd

The integrated gasification combined cycle (IGCC) concept is gaining acceptance as the Clean Coal technology with the best potential for continued improvement in performance and continued reduction in capital cost. In large part this potential will be realized by optimizing the integration of power generation and fuel conversion subsystems and by exploiting advances in gas turbine technology. This paper discusses the impact that technology advances in the gas turbine combined cycle are having on the commercial viability of the IGCC concept. Technical innovations in such areas as coal gas combustion, plant control, and system integration will ensure that IGCC technology will continue to advance well into the future.


Author(s):  
Xiaomo Jiang ◽  
TsungPo Lin ◽  
Eduardo Mendoza

Condition monitoring and diagnostics of a combined cycle gas turbine (CCGT) power plant has become an important tool to improve its availability, reliability, and performance. However, there are two major challenges in the diagnostics of performance degradation and anomaly in a single-shaft combined cycle (CC) power plant. First, since the gas turbine (GT) and steam turbine (ST) in such a plant share a common generator, each turbine's contribution to the total plant power output is not directly measured, but must be accurately estimated to identify the possible causes of plant level degradation. Second, multivariate operational data instrumented from a power plant need to be used in the plant model calibration, power splitting, and degradation diagnostics. Sensor data always contain some degree of uncertainty. This adds to the difficulty of both estimation of GT to ST power split (PS) and degradation diagnostics. This paper presents an integrated probabilistic methodology for accurate power splitting and the degradation diagnostics of a single-shaft CC plant, accounting for uncertainties in the measured data. The method integrates the Bayesian inference approach, thermodynamic physics modeling, and sensed operational data seamlessly. The physics-based thermodynamic heat balance model is first established to model the power plant components and their thermodynamic relationships. The model is calibrated to model the plant performance at the design conditions of its main components. The calibrated model is then employed to simulate the plant performance at various operating conditions. A Bayesian inference method is next developed to determine the PS between the GT and the ST by comparing the measured and expected power outputs at different operation conditions, considering uncertainties in multiple measured variables. The calibrated model and calculated PS are further applied to pinpoint the possible causes at individual components resulting in the plant level degradation. The proposed methodology is demonstrated using operational data from a real-world single-shaft CC power plant with a known degradation issue. This study provides an effective probabilistic methodology to accurately split the power for degradation diagnostics of a single-shaft CC plant, addressing the uncertainties in multiple measured variables.


2005 ◽  
Vol 128 (4) ◽  
pp. 796-805 ◽  
Author(s):  
Yongjun Zhao ◽  
Vitali Volovoi ◽  
Mark Waters ◽  
Dimitri Mavris

Traditionally, gas turbine power plant preventive maintenance schedules are set with constant intervals based on recommendations from the equipment suppliers. Preventive maintenance is based on fleet-wide experience as a guideline as long as individual unit experience is not available. In reality, the operating conditions for each gas turbine may vary from site to site and from unit to unit. Furthermore, the gas turbine is a repairable deteriorating system, and preventive maintenance usually restores only part of its performance. This suggests a gas turbine needs more frequent inspection and maintenance as it ages. A unit-specific sequential preventive maintenance approach is therefore needed for gas turbine power plant preventive maintenance scheduling. Traditionally, the optimization criteria for preventive maintenance scheduling is usually cost based. However, in the deregulated electric power market, a profit-based optimization approach is expected to be more effective than the cost-based approach. In such an approach, power plant performance, reliability, and the market dynamics are considered in a joint fashion. In this paper, a novel idea that economic factors drive maintenance frequency and expense to more frequent repairs and greater expense as equipment ages is introduced, and a profit-based unit-specific sequential preventive maintenance scheduling methodology is developed. To demonstrate the feasibility of the proposed approach, a conceptual level study is performed using a base load combined cycle power plant with a single gas turbine unit.


Author(s):  
M J Moore

The increase, in recent years, in the size and efficiency of gas turbines burning natural gas in combined cycle has occurred against a background of tightening environmental legislation on the emission of nitrogen oxides. The higher turbine entry temperatures required for efficiency improvement tend to increase NOx production. First-generation emission control systems involved water injection and catalytic reduction and were relatively expensive to operate. Dry low-NOx combustion systems have therefore been developed but demand more primary air for combustion. This gives added incentive to the reduction of air requirements for cooling the combustor and turbine blading. This paper reviews the various approaches adopted by the main gas turbine manufacturers which are achieving very low levels of NOx emission from natural gas combustion. Further developments, however, are necessary for liquid fuels.


1980 ◽  
Author(s):  
R. P. Shah ◽  
D. J. Ahner ◽  
G. R. Fox ◽  
M. J. Gluckman

The performance of combined cycle power plants integrated with advanced air- and oxygen-blown entrained gasification systems as well as with advanced oxygen-blown fixed bed gasifiers will be presented. The performance and cost of such plants using near-term gas turbine technology will be compared to the performance of conventional coal-fired steam plants with FGD. The integrated combined cycle plant appears attractive at today’s gas turbine firing temperatures. Further benefits from advanced gas turbine operating conditions on the performance and economics of such plants and the rationale for these performance trends will be discussed.


Author(s):  
Yongjun Zhao ◽  
Vitali Volovoi ◽  
Mark Waters ◽  
Dimitri Mavris

Traditionally the gas turbine power plant preventive maintenances are scheduled with constant maintenance intervals based on recommendations from the equipment suppliers. The preventive maintenances are based on fleet wide experiences, and they are scheduled in a one-size-fit-all fashion. However, in reality, the operating conditions for each gas turbine may vary from site to site, and from unit to unit. Furthermore, the gas turbine is a repairable deteriorating system, and preventive maintenance usually restores only part of its performance. This suggests the gas turbines need more frequent inspection and maintenance as it ages. A unit specific sequential preventive maintenance approach is therefore needed for gas turbine power plants preventive maintenance scheduling. Traditionally the optimization criteria for preventive maintenance scheduling is usually cost based. In the deregulated electric power market, a profit based optimization approach is expected to be more effective than the cost based approach. In such an approach, power plant performance, reliability, and the market dynamics are considered in a joint fashion. In this paper, a novel idea that economics drive maintenance expense and frequency to more frequent repairs and greater expense as the equipment and components age is introduced, and a profit based unit specific sequential preventive maintenance scheduling methodology is developed. To demonstrate the feasibility of the proposed approach, this methodology is implemented using a base load combined cycle power plant with single gas turbine unit.


1974 ◽  
Author(s):  
R. E. Sieck ◽  
N. P. Baudat ◽  
J. I. Alyea

The desire to extract ethane and propane from the natural gas produced by off-shore wells in the Gulf of Mexico, led to the erection of the Cryogenic Gas Processing Plant near Erath, Louisiana. This paper describes the application of a combined cycle (gas/steam turbine) for gas compression and transmission. The installation is none of, if not, the largest and most efficient combined cycles in mechanical drive service, capable of handling over 1200 MMscf/d of gas. The installation incorporates a gas turbine rated 46,800 hp at ISO conditions and a steam turbine rated 29,700 hp. In addition, the cycle incorporates the use of gas turbine variable inlet guide vanes, a supplementary fired waste heat recovery boiler and forced draft fan for independent steam turbine operation.


Author(s):  
Do Won Kang ◽  
Chang Min Kim ◽  
Tong Seop Kim ◽  
Jeong L. Sohn

This study aims to provide a systematic overview of the relations between IGCC performance and major design and operating parameters such as integration degree, nitrogen dilution, and ambient temperature. A unique feature of this study is that allowable maximum values of both the gas turbine power ouput and the turbine blade temperature were considered. For this purpose, a simulation tool to predict operation and performance of a syngas turbine, which was modified from a base gas turbine model, was set up using off-design models. Then, an entire integrated gasification combined cycle using the syngas turbine was modeled. The power block (i.e. the combined cycle) was modeled in detail and mass and energy interactions of the power block with a gasifier block and an air separation unit were included. Variation in syngas turbine power output according to varying nitrogen dilution was simulated and operating conditions where gas turbine power needs to be suppressed to the allowable maximum value were found out. Maximum net IGCC power output under the limitations of gyngas turbine power and blade temperature was predicted for various integration degrees in a wide ambient temperature range. The influence of steam dilution on plant performance was also investigated.


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