Two Phase Flow CFD Modeling to Enhance Steam Turbines LP Stages Performance Predictability: Comparison With Data and Correlations

2020 ◽  
Author(s):  
Nicola Maceli ◽  
Lorenzo Arcangeli ◽  
Andrea Arnone
Keyword(s):  
Power Generation ◽  
Power Plants ◽  
Raw Materials ◽  
Sustainable Use ◽  
Waste To Energy ◽  
Cfd Modeling ◽  
Reliable Estimate ◽  
Primary Role ◽  
Steam Turbines ◽  
Two Phase

Abstract The whole energy market, from production plants to end-users, is marked by a strong impulse towards a sustainable use of raw materials and resources, and a reduction of its carbon foot-print. Increasing the split of energy produced with renewables, improving the efficiency of the power plants and reducing the waste of energy appear to be mandatory steps to reach the goal of sustainability. The steam turbines are present in the power generation market with different roles: they are used in fossil, combined cycles, geothermal and concentrated solar plants, but also in waste-to-energy and heat recovery applications. Therefore, they still play a primary role in the energy production market. There are many chances for efficiency improvement in steam turbines, and from a rational point of view, it is important to consider that the LP section contributes to the overall power delivered by the turbine typically by around 40% in industrial power generation. Therefore, the industry is more than ever interested in developing methodologies capable of providing a reliable estimate of the LP stages efficiency, while reducing development costs and time. This paper presents the results obtained using a CFD commercial code with a set of user defined subroutines to model the effects of non-equilibrium steam evolution, droplets nucleation and growth. The numerical results have been compared to well-known test cases available in literature, to show the effects of different modeling hypotheses. The paper then focuses on a test case relevant to a cascade configuration, to show the code capability in terms of bladerow efficiency prediction. Finally, a comprehensive view of the obtained results is done through comparison with existing correlations.

Elements of a Successful Waste-to-Energy Boiler Upgrade

2009 ◽  
Author(s):  
Samit J. Pethe ◽  
Chris Dayton ◽  
Marcel D. Berz ◽  
Tim Peterson
Keyword(s):  
Waste To Energy ◽  
Cfd Modeling ◽  
Steam Turbines ◽  
Steam Generation ◽  
Operator Training ◽  
Refuse Derived Fuel ◽  
Energy Plant ◽  
History Of ◽  
Emission Limits ◽  
Combustible Gases

Great River Energy operates a waste-to-energy plant in Elk River, Minnesota. The plant burns 850 tons per day of refuse derived fuel (RDF) in three boilers, and its three steam turbines can produce 32 MW of electricity. In the largest of the three units, the No. 3 Boiler, steam generation was restricted by carbon monoxide (CO) and nitrogen oxides (NOx) emission limits. The plant had an interest in improving the combustion performance of the unit, thereby allowing higher average RDF firing rates while staying within emissions compliance. The project was initiated by an engineering site visit and evaluation. The boiler had a history of unstable burning on the stoker grate, which required periodic natural gas co-firing to reduce CO levels. As an outcome to the evaluation, it was decided to install a new overfire air (OFA) system to improve burnout of combustible gases above the grate. Current and new OFA arrangements were evaluated via Computational Fluid Dynamics (CFD) modeling. The results illustrated the limitations of the original OFA system (comprised of multiple rows of small OFA ports on the front and rear furnace walls), which generated inadequate mixing of air and combustible gases in the middle of the boiler. The modeling illustrated the advantages of large and fewer OFA nozzles placed on the side walls in an interlaced pattern, a configuration that has given excellent performance on over 45 biomass-fired boilers of similar design upgraded by Jansen Combustion and Boiler Technologies, Inc. (JANSEN). Installation of the new OFA system was completed in April of 2008. Subsequent testing of the No. 3 Boiler showed that it could reliably meet the state emission levels for CO and NOx (200 ppm and 250 ppm, respectively, corrected to 7% dry flue gas oxygen) while generating 24% more steam than a representative five month period prior to the upgrade. This paper describes the elements that led to a successful project, including: data collection, engineering analyses, CFD modeling, system design, equipment supply, installation, operator training, and startup assistance.

How Combined Cycle Configuration is Impacted by Current Power Market Requirements

2012 ◽  
Author(s):  
Justin Zachary
Keyword(s):  
Power Generation ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Spare Parts ◽  
Combined Cycle ◽  
Lessons Learned ◽  
Steam Turbines ◽  
Equipment Selection ◽  
Plant Configuration

In the past 20 years, the equipment manufacturers have made significant strives to develop better and more cost effective products: gas turbines, steam turbines, Heat Recovery Steam Generators (HRSG), water treatment, fuel treatment equipment etc. Consequently, the Combined Cycle Power Plants (CCPP) have become, due to many technological breakthroughs, the most efficient form of electrical power generation from fossil fuel, reaching or exceeding net efficiencies of 60%. We are also witnessing a substantial penetration of Renewable in the power generation mix. The Renewable intermittent nature of generation associated with new grid requirements for spinning reserves and/or frequency control must be considered when new CCPP are conceptually designed. The paper will examine several CCPP configurations, involving one, two, and three gas turbines. Substantial improvements in the efficiency are usually associated with an increased gas turbines electrical output. Various scenarios of plant configurations with targeted, sensible level of integration will be examined. The challenges of major equipment selection (gas turbines, heat recovery steam generator steam turbines, heat sink) for each of the configurations will be examined from an EPC (Engineering, Procurement, Construction) Contractor perspective, based on the lessons learned from the development and execution of more than 30 advanced CCPPs. A special emphasis will be given to the strategy of providing the CCPP with fast start-up, capability, rapid load changes, without negatively impacting part-load efficiencies and emissions. The effect of plant configuration on plant reliability, maintenance requirements and recommended spare parts will also be discussed. Finally the paper describes the lessons learned, in plant configuration selection that can be successfully employed on future projects through judicious equipment selection at the development phase, design optimization and proper project management at the execution phase.

Two Phase Flow CFD Modeling of a Steam Turbine Low Pressure Section: Comparison With Data and Correlations

2021 ◽  
Author(s):  
Nicola Maceli ◽  
Lorenzo Arcangeli ◽  
Andrea Arnone
Keyword(s):  
Experimental Data ◽  
Steam Turbine ◽  
Low Pressure ◽  
Performance Model ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Steam Turbines ◽  
Two Phase ◽  
Scaled Model ◽  
Application Range

Abstract Testing a sub-component or testing a scaled model are the approaches currently used to reduce the development cost of the new low-pressure (LP) section of a steam turbine. In any case, testing campaigns are run at a limited number of operating conditions. Therefore, some correlations are used to build a performance model of the LP module and expand the usage of a limited set of experimental data to cover the application range encountered in the steam turbine market. Another approach, which has become feasible during the last decade, is the usage of CFD calculations. These two approaches include a certain amount of uncertainty in the performance of the LP section, mainly related to the losses caused by the moisture content in the flow. In the present paper, the results of the analysis of a cutting-edge low-pressure section for small steam turbines are presented. The results are obtained by using a CFD commercial code with a set of user defined subroutines to model the effects of droplets nucleation and growth. Different operating conditions are considered, with different wetness at the exit and different pressure ratios, in order to clearly show the loss trend for different levels of exit moisture. The numerical results are compared with the experimental data, showing a significant improvement in the performance predictability for the considered case and demonstrating the benefit of using a CFD approach instead of using existing correlations.

Life Cycle Assessment on Environmental Impact of Wind Power Turbines

2013 ◽  
Vol 448-453 ◽  
pp. 1897-1903
Author(s):  
Jia Hua Dong ◽  
Wei Guang Zhu ◽  
Cheng Kang Gao
Keyword(s):  
Power Generation ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Energy Consumption ◽  
Environmental Impact ◽  
Wind Power ◽  
Power Plants ◽  
Raw Materials ◽  
Renewable Energy Sources ◽  
Wind Power Generation

Wind power is an important type of renewable energy sources. In this passage we will apply Life Cycle Assessment (LCA) to analyze the four stages of wind power generation,which are production of raw materials, transportation, build-operate process of wind plants and demolition stages, calculate the energy consumption and the environmental impact, set a contrastive analysis between coal-fired power plants and wind power plants. We will take WangHaiSi Wind Plant in Faku, Shenyang as an example to show the difference between the two ways of getting power. The analysis shows that: in comparison with coal-fired generation, wind power generation saves more energy and reduces emissions of pollutants markedly; the main energy consumption comes from production of raw materials, which takes 79.3% of the total energy consumption throughout the life cycle. In the meantime, the large amount of ecological resources consumption from construction, operation and maintenance of wind plants leads to mass emission of carbon dioxide and sulfur dioxide, which respectively take 67.3% and 96.6% of total emissions. Besides, wind generation only accounts for 0.93%, 0.89% and 2.72% of energy consumption, global warming potential (GWP) and acid potential (AP) of coal-fired power generation. Thus, it proved that wind power generation has lesser impacts on environment than coal-fired power generation. However, it is still of great necessity to strengthen the environmental protection measures to reduce the consumption and destroy of ecologic resources.

Flexible and Economical Operation of Power Plants: 25 Years of Expertise

2012 ◽  
Author(s):  
Jan Greis ◽  
Edwin Gobrecht ◽  
Steffen Wendt
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Power Plants ◽  
Operating Experience ◽  
Life Time ◽  
Steam Turbines ◽  
Start Up ◽  
Hot Start ◽  
Fast Cooling ◽  
Short Time

Within the last years the idea of running a conventional power plant has changed. Fluctuating power generation by solar power and wind parks creates a need for highly flexible backup power plants. This need quickly arose within the last 5 years and the market is still searching for a solution. Single steam turbine manufacturers can provide features to react more flexibly, quickly and to prolong component life time. Thus, considerable operating experience has already been in existence for many years. New highly efficient steam turbines are already equipped with solutions to serve an ambitious market. But also, for existing units, different modernization packages can be provided along with hardware and software modifications which allow power plants to supply power at a moment’s notice. This paper presents the overall approach and the possible field of application for the well-established features of Siemens steam turbines. Starting a power plant within a short time to fill the gap of fluctuating power generation is an important capability in order to participate in today’s and tomorrow’s energy market. A fully automated start-up procedure to avoid any delays contributes in fulfilling this requirement. Optimized component geometries guarantee the shortest start-up times. Furthermore, a parallel start-up of gas and steam turbines (Hot Start on the Fly) has already been proven for many years. Regarding flexibility, the improvement of start-up time is only one major aspect. Another important task is to provide the opportunity to influence scheduled maintenance outages. Therefore, steam turbines can be equipped with software which allows the customer to plan the power plant’s outages in accordance with single components requirements, e.g. GT outages. The lifecycle counter enables customers to evaluate the optimum between start-up time and life time consumption based on dynamic equivalent operating hours. In addition, fast cooling procedures help to keep outage times to a minimum.

Strategies for Integration of Advanced Gas and Steam Turbines in Power Generation Applications

2007 ◽  
Author(s):  
Justin J. Zachary
Keyword(s):  
Power Generation ◽  
Gas Turbines ◽  
Power Plants ◽  
Electrical Power ◽  
Cost Effective ◽  
Combined Cycle ◽  
Pollutant Removal ◽  
Steam Turbines ◽  
Turbine Cooling ◽  
Removal Technologies

Combined cycle power plants (CCPPs) using fossil fuel generate the cleanest and most efficient form of electrical power. CCPP technologies have evolved significantly in providing better, more cost-effective products: gas turbines (GTs), steam turbines (STs), heat recovery steam generators (HRSGs), heat sinks, pollutant removal technologies, balance of plant (BOP), water treatment and fuel treatment equipment, etc. A major reason for these improvements was the introduction of the G and H technologies for gas turbines, in which an inseparable thermodynamic and physical link was created between the primary and secondary power generation systems by using steam instead of air, in a closed loop to perform most (or all) turbine cooling activities.

Analysis of the Possibility of Water Induction in Turbine From Direct Contact Water Heater at Load Shedding Power

2013 ◽  
Author(s):  
M. A. Gotovsky ◽  
V. F. Ermolov ◽  
V. E. Mikhailov ◽  
Yu. G. Sukhorukov ◽  
N. N. Trifonov
Keyword(s):  
Direct Contact ◽  
Nuclear Power ◽  
Power Plants ◽  
Feed Water ◽  
Steam Turbines ◽  
Water Heater ◽  
Two Phase ◽  
Long Time ◽  
Flow Rate Control ◽  
Churn Flow

Direct-contact heaters of feed water are especially popular as low-pressure heaters (LPH). These devices are successfully used in Russia during a long time both for conventional and nuclear power plants. Moreover, abilities of such devices to operate as deaerators led to the development deaeratorless schemes. One of most important conditions of reliable operating of such LPH is the prevention of damage of steam turbines, because of back flow of wet steam to the turbine. In this paper processes of boiling up are considered in direct contact LPH-2 which occur during stopping of turbine and its specific features concerned with dependence of sonic speed two-phase flow on vapor and liquid volumetric portions during flow enter in compensating tubes. Computer analysis showed, that the rate of generation of steam in the superheated water depends on the pressure exceptionally strong. Zone of churn flow regime, which is formed in the upper part of the condensate tank appears very sensitive instrument of flow rate control. As it is shown in such a situation, the system becomes self-governing and will not miss a steam consumption, which leads to the entrance some part of churn regime zone to pressure equalizing tubes. The calculations show that the safety can be ensure even in the conditions when backpressure valve absent. Such the conclusion is confirmed by the experience on operation direct contact LPH in Russian power plants.

Contrastive Analysis between Wind Power Generation and Coal Generation on the Environmental Impact Assessment

2013 ◽  
Vol 316-317 ◽  
pp. 254-258
Author(s):  
Jia Hua Dong ◽  
Wei Guang Zhu ◽  
Cheng Kang Gao ◽  
Han Mei Tang
Keyword(s):  
Power Generation ◽  
Life Cycle ◽  
Energy Consumption ◽  
Environmental Impact ◽  
Wind Power ◽  
Power Plants ◽  
Raw Materials ◽  
Renewable Energy Sources ◽  
Wind Power Generation ◽  
Contrastive Analysis

Wind power is an important type of renewable energy sources. In this passage we will apply Life Cycle Assessment to analyze the four stages of wind power generation，which are production of raw materials, transportation, build-operate process of wind plants and demolition stages, calculate the energy consumption and the environmental impact, set a contrastive analysis between coal-fired power plants and wind power plants. We will take WangHaiSi Wind Plant in Faku, Shenyang as an example to show the difference between the two ways of getting power. The analysis shows that: in comparison with coal-fired generation, wind power generation saves more energy and reduces emissions of pollutants markedly; the main energy consumption comes from production of raw materials, which takes 79.3% of the total energy consumption throughout the life cycle. In the meantime, the large amount of ecological resources consumption from construction, operation and maintenance of wind plants leads to mass emission of carbon dioxide and sulfur dioxide, which respectively take 67.3% and 96.6% of total emissions. Besides, wind generation only accounts for 0.93%, 0.89% and 2.72% of energy consumption, global warming potential (GWP) and acid potential (AP) of coal-fired power generation. Thus, it proved that wind power generation has lesser impacts on environment than coal-fired power generation. However, it is still of great necessity to strengthen the environmental protection measures to reduce the consumption and destroy of ecologic resources.

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