HRSGs for Combined Cycle Plants: Design Considerations and Life Consumption Estimation Using Dynamic Software

2011 ◽  
Author(s):  
Suichu Sun ◽  
Akber Pasha
Keyword(s):  
Economic Benefits ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Damage Mechanisms ◽  
Start Up ◽  
On Line ◽  
Critical Components ◽  
Life Consumption ◽  
The Impact ◽  
Plant Power

Today’s Heat Recovery Steam Generators are exposed to more severe operation than just running at a base load. The deregulation of the electric generation industry has resulted in an increase of merchant plants that are required to supply electrical power to the grid as needed and when needed. The plants will be coming on line with minimal notice. This puts a strain on the HRSG and unless properly designed and operated to withstand the quick start-ups and shut downs, the integrity will be compromised. Fast starts result in achieving full load revenues much sooner including the cost of high start-up emission reduction. Basic definition of a fast start is to have about 66% of the plant power available in 30–50 minutes and full plant power available in 60–75 minutes with a hot or warm steam turbine. This paper describes various mechanisms which affect the integrity of the boilers. These include the damage mechanisms, their effect on various parts and how to control them. The causes and the end results of these damage mechanisms are not the same for all components of the boiler. This analysis results in deciding which components need further review of the critical components. Detailed analysis of the critical components under the specified operating conditions can lead the nature and origin of the forces causing adverse impact on the life of the component. Once the failure mechanism is determined, means to eliminate or reduce the impact can be developed. This paper also describes the Life Consumption Estimation software which uses the data directly retrieved from the plant data acquisition system, thus eliminating the tedious task of manual data transmission. Based on the correlations developed by Vogt Power International Inc. (VPI) with the detailed dynamic simulation, Finite Element Analysis and various codes the component consumption is estimated and displayed with the calculated replacement and start-up costs on a continual basis. This gives the plant owners and operators an on line tool to gauge the economic benefits of the aggressive operations in real time.

scholarly journals Industrial Gas Turbine Performance: Compressor Fouling and On-Line Washing

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Uyioghosa Igie ◽  
Pericles Pilidis ◽  
Dimitrios Fouflias ◽  
Kenneth Ramsden ◽  
Panagiotis Laskaridis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Operating Conditions ◽  
Compressor Cascade ◽  
Compressor Blades ◽  
Turbine Performance ◽  
Industrial Gas Turbines ◽  
On Line ◽  
The Impact

Industrial gas turbines are susceptible to compressor fouling, which is the deposition and accretion of airborne particles or contaminants on the compressor blades. This paper demonstrates the blade aerodynamic effects of fouling through experimental compressor cascade tests and the accompanied engine performance degradation using turbomatch, an in-house gas turbine performance software. Similarly, on-line compressor washing is implemented taking into account typical operating conditions comparable with industry high pressure washing. The fouling study shows the changes in the individual stage maps of the compressor in this condition, the impact of degradation during part-load, influence of control variables, and the identification of key parameters to ascertain fouling levels. Applying demineralized water for 10 min, with a liquid-to-air ratio of 0.2%, the aerodynamic performance of the blade is shown to improve, however most of the cleaning effect occurred in the first 5 min. The most effectively washed part of the blade was the pressure side, in which most of the particles deposited during the accelerated fouling. The simulation of fouled and washed engine conditions indicates 30% recovery of the lost power due to washing.

Maximizing Plant Power Output Using Dry Cooling System

2004 ◽  
Author(s):  
Ram Chandran
Keyword(s):  
Power Output ◽  
Cooling System ◽  
Combined Cycle ◽  
Ambient Temperatures ◽  
Turbine Efficiency ◽  
The Cost ◽  
The Impact ◽  
Lower Plant ◽  
Plant Power ◽  
Dry Cooling

As the power industry is deregulated, the cost of power plays a major role in obtaining long-term Power Purchase agreements. More and more plants, now, are developed with Dry Cooling System for condensing steam from the steam turbine of combined cycle plants or coal-fired plants. However, Dry Cooling has become synonymous with lower plant output. This paper presents solutions to dispel that myth. 1. Options available for control of the air-cooled system, their initial cost and the impact on minimizing internal power consumption and maximizing plant power output. 2. The air-cooled condenser operates normally at high turbine exhaust pressures during high ambient temperatures. The high backpressure results in lower turbine efficiency and lower plant output. Various options available are presented to combat this deficiency to maximize power output.

Ansaldo Energia Gas Turbine Technology Developments

2018 ◽  
Author(s):  
A. D. Ramaglia ◽  
U. Ruedel ◽  
V. Stefanis ◽  
S. Florjancic
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Axial Flow ◽  
Assessment Method ◽  
Combined Cycle ◽  
Optimization Techniques ◽  
Operating Conditions ◽  
Multidisciplinary Optimization ◽  
Successful Operation ◽  
The Impact

The operating conditions of the gas turbine combined cycle (GTCC) power plants have significantly changed over the last few years and are directed towards an improved operational and fuel flexibility, increased GT power output and efficiency and improved component lifetime. The purpose of this paper is to provide an overview of the development, analysis and validation of modern gas turbine features, parts and components for the AE64.3, AE94.2, AE94.3A, the GT26 and GT36. The development of compressor blades with a low uncertainty using multidisciplinary optimization techniques is outlined while the lifetime of a welded rotor is quantified using a damage-tolerant lifetime assessment method based on experimental creep data. For the lateral dynamics of the shaft train a modal-based approach supported by elastic structures will be described. For the axial flow turbine, the aerodynamic and heat transfer related design and validation of film cooled vanes and blades will be introduced with a particular focus on the tip area, the platforms and the application of under-platform dampers. Furthermore, the impact of the combustor-turbine interface on the turbine vane aerodynamics and film cooling characteristics is shown. For the continued very successful operation of the Constant Pressure Sequential Combustion System (CPSC), the thermos-acoustic activities of can combustors as well as the rig-to-engine transferability are presented. Recent approaches to the development of SLM parts for turbine hardware, specifically the approach used to select process parameters and creation of preliminary material models will also be briefly summarized.

Thermal Modeling of HRSG Transient Behavior in Combined Cycle Power Plants

2006 ◽  
Author(s):  
Sepehr Sanaye ◽  
Moein Rezazadeh ◽  
Jalaleddin Oladi ◽  
Gholam Hossein Sadeghpoor ◽  
Farid Bashiri ◽  
...  
Keyword(s):  
Steady State ◽  
Power Plants ◽  
Cold Start ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Master Program ◽  
Load Change ◽  
Start Up ◽  
Program Software ◽  
Transient And Steady State

Combined Cycle Power Plants (CCPP) are attractive electricity generation systems due to high cycle efficiency and quick response of the system to load change. Heat recovery steam generator (HRSG) is an important part of a CCPP and it is important to predict the HRSG operating conditions in transient and steady state modes. It should be emphasized that the biggest pressure and thermal stresses are imposed on HRSG superheater and evaporator tubes banks during transient periods (cold start up and load change). Due to these effects a software program was developed for analyzing the HRSG transient and steady state operating conditions. The HRSG software included arbitrary number of pressure levels (usually up to three) and any number of elements (superheater, evaporator, economizer, desuperheater and duct burner). In this paper theories and equations (mass/energy balance and heat transfer coefficients) applied for HRSG thermal analysis are described. Also HRSG program software outputs were compared with real data collected from HRSG cold start-up at Tehran CCPP with specified geometry and arrangement of elements. The closeness of two groups of data in this transient and steady state modes was acceptable. The numerical outputs in steady state condition also were found very close to GT MASTER program software outputs.

Impact of Operating Regime on Economic Performamnce of Combined Cycle Power Plants

2005 ◽  
Author(s):  
Mircea Fetescu
Keyword(s):  
Economic Performance ◽  
Capital Investment ◽  
Power Plants ◽  
Operating Regime ◽  
Combined Cycle ◽  
Economic Feasibility ◽  
Start Up ◽  
Wide Range ◽  
The Impact ◽  
Base Load

It is accepted that CCPP has the highest fuel conversion efficiency among fossil fuel fired generation technologies. The extensive installed base of CCPP worldwide is justified by additional advantages: low capital investment, short construction time, low environmental impact and high operating flexibility. The operating flexibility, with fast loading and deloading and short start-up and shutdown durations, allows CCPPs to fulfill a wide range of operating duties, such cycling, intermediate load to base load, grid frequency or voltage control and part load operation; mostly on a competitively generated cost basis. The traditional approach to CCPP development is to design an optimised plant, taking into consideration the technical and economic boundary conditions of a specific project. This includes assumptions for operating regime: base load, intermediate load or cycling with daily start-up and shutdown. In a deregulated environment, plants are dispatched on merit. The assumptions related to operating regime and used for optimising the configuration of a particular CCPP, often deviate significantly during commercial operation. The objective of this work is to evaluate the impact of the operating regime on CCPP economic performance. During the economic feasibility evaluation of a power project it is frequently considered that the main factors affecting the electricity generation cost, are capital cost and fuel cost. As far as the operating regime is concerned, a number for yearly operating hours is then assumed and eventually sensitivity is considered. The content of this work is an investigation on how the capital, fuel and O&M costs, components of the generation costs, are affected by the utilisation factor, by operating modes and loads, frequency and duration of start-up and shudown [s&s] of the plant. The conclusion of the paper is that both, operating regime and operating procedure have an important impact on economic performance of combined cycle plants. Annual operating hours and the number of s&s influence the factors which contribute to the profitability and competitiveness of the plant, such as EOH, availability, performance degradation, O&M costs and directly the average plant output and efficiency. Finally the economic performance of combined cycle plants can be significantly improved by re-visiting the conceptual design and the operating concept.

Gas Turbine Combined Cycle Flexibility: A Dynamic Model for Compressor Intake Conditioning Through a Heat-Pump

2019 ◽  
Author(s):  
Iacopo Rossi ◽  
Luca Piantelli ◽  
Alberto Traverso
Keyword(s):  
Air Temperature ◽  
Power Plants ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Plant Performance ◽  
Cycle Performance ◽  
Ambient Conditions ◽  
Modeling Framework ◽  
Critical Feature ◽  
The Impact

Abstract The flexibility of power plants is a critical feature in energy production environments nowadays, due to the high share of non-dispatchable renewables. This fact dramatically increases the number of daily startups and load variations of power plants, pushing the current technologies to operate out of their optimal range. Furthermore, ambient conditions significantly influence the actual plant performance, creating deviations against the energy sold during the day-ahead and reducing the profit margins for the operators. A solution to reduce the impact of unpredicted ambient conditions, and to increase the flexibility margins of existing combined cycles, is represented by the possibility of dynamically controlling the temperature at compressor intake. At present, cooling down the compressor intake is a common practice to govern combined cycle performance in hot regions such as the Middle East and Africa, while heating up the compressor intake is commonly adopted to reduce the Minimum Environmental Load (MEL). However, such applications involve relatively slow regulation of air intake, mainly coping with extreme operating conditions. The use of continuously varying, at a relatively quick pace, the air temperature at compressor intake, to mitigate ambient condition fluctuations and to cope with electrical market requirements, involves proper modeling of the combined cycle dynamic behavior, including the short-term and long-term impacts of intake air temperature variations. This work presents a dynamic modeling framework for the whole combined cycle applied to one of IREN Energia’s Combined Cycle Units. The paper encloses the model validation against field data of the target power plant. The validated model is then used to show the potential in flexibility augmentation of properly adjusting the compressor intake temperature during operation.

Automated Design Life Evaluation for a Gas Turbine HRSG

2005 ◽  
Author(s):  
Steve V. Torkildson ◽  
Susheerlal Somasundaran
Keyword(s):  
Evaluation Process ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Design Stage ◽  
Thermal Gradients ◽  
Element Analysis ◽  
Life Evaluation ◽  
Start Up ◽  
Analysis Computer ◽  
Pressure Part

Many combined cycle plants operate only during peak demand hours and start/stop at least once a day, Exposure of the HRSG to the repeated thermal gradients experienced during start-up has raised questions about fatigue durability. Additionally, portions of the superheater and reheater sections operate in the creep range and owners want assurance that these parts will provide 25–30 years of life. This paper illustrates the development of an automated process to evaluate the effects of creep and cycling induced fatigue. The process employs a dynamic thermal analysis computer program, spreadsheets, and finite element analysis to complete a comprehensive fatigue/creep evaluation of every significant pressure part in the HRSG. An automated life evaluation process offers many advantages to the owner. During the design stage of the project, the analysis allows designers to provide for correct materials and adequate strength. Once the plant is in operation, changed operating conditions can be easily evaluated to determine their effect on HRSG life.

Development of Excess Phosphorus Removal Characteristics in a Sequencing Batch Reactor

1992 ◽  
Vol 25 (4-5) ◽  
pp. 433-440 ◽  
Author(s):  
H.-S. Shin ◽  
H.-B. Jun
Keyword(s):  
Phosphorus Removal ◽  
Impact Load ◽  
Batch Reactor ◽  
Operating Conditions ◽  
Biological Phosphorus Removal ◽  
Start Up ◽  
The Impact ◽  
Biological Phosphorus ◽  
Operating Method ◽  
Removal System

Biological phosphorus removal mechanisms become popular in activated sludge wastewater treatment systems due to their economy and efficiency. The objectives of this paper are to develop the excess phosphorus removal system in a short start-up period and to find the optimal operating conditions. In this experiment, excess phosphorus removal was achieved in a week on the proposed operating method which is to keep substrate zero before the start of aerobic react. The removal raters of both TOC and phosphorus were above 98 % in one week operation. Phosphorus removal bacteria can utilize glucose as well as acetate and also use nitrate as a single electron acceptor. The developed excess phosphorus removal system had good Stability against the impact load.

Rotor Life Prediction and Improvement for Steam Turbines Under Cyclic Operation

2011 ◽  
Author(s):  
Damaso Checcacci ◽  
Lorenzo Cosi ◽  
Sanjay Kumar Sah
Keyword(s):  
Steam Turbine ◽  
Turbine Rotor ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Steam Turbines ◽  
Power Utility ◽  
Simplified Approach ◽  
Cyclic Operation ◽  
Combined Cycle Plant ◽  
The Impact

The evolution of the energy market is leading to a general increase in demand for cyclic operation and rapid startup capability for steam turbines utilized in power utility plants. As a consequence, turbine manufactures must optimize designs to minimize transient stress and make available to plant operators the necessary understanding of the impact of operating conditions on parts life. In addition, if continuous duty operation is not economical for an existing plant, operators considering switching to the cyclic mode need to take into account the cost associated with reduced maintenance intervals and parts replacement. This paper presents the methodologies applied to assess and optimize steam turbine rotor life. The discussion stems from the case analysis of a 60 MW steam turbine that was operated almost uninterrupted for 10 years in a combined cycle plant and was then expected to switch to cyclic operation with approx 250 startups/year. The effects of different rotor geometries on transient thermal stress/strain conditions are presented along with the consequences of startup sequence modifications for rotor life vs. on-line time. The discussion is supported by modeling details and results from transient thermomechanical FEM analyses. The possibility of a simplified approach in the form of approximate models for the analysis of such behavior on a project basis is also addressed.

Active On-Line Protective Tuning Adjustment Technique to Achieve Better Availability and Performance in Pre-Mix DLN Combustion

2003 ◽  
Author(s):  
C. Koeneke ◽  
M. Nomura ◽  
H. Iba ◽  
T. Kawakami ◽  
T. Koga
Keyword(s):  
Gas Turbines ◽  
Pressure Fluctuations ◽  
Calorific Value ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Protection System ◽  
Fuel Quality ◽  
Flame Instability ◽  
On Line ◽  
And Performance

Stable combustion of gas turbines is essential to ensure reliability, availability and achieve maximum component life capability. Combustor instabilities can trigger high-pressure fluctuations that are generally due to sudden changes in fuel calorific value or fuel quality, large ambient temperature swings, or sudden changes in operating load conditions. In order to protect against combustor instabilities, Mitsubishi developed an advanced monitoring and protection system known as the Advanced Combustor Pressure Fluctuation Monitoring (advanced CPFM) system. This on-line monitoring and protection system automatically tunes the air bypass valve, main and pilot fuel flows to maintain appropriate fuel/air ratio depending on the combustion chamber flame instability condition. The response to such actions successfully prevents flame out occurrence, combustion oscillation, and flame flash back under various modes while trying to maintain emissions within specified levels. This paper describes the operation and functionalities of the advanced CPFM system that has been tested at Mitsubishi’s in-house combined cycle power plant under real operating conditions.

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