Dynamic Performance of a Combined Gas Turbine and Air Bottoming Cycle Plant for Off-Shore Applications

2014 ◽  
Author(s):  
Alberto Benato ◽  
Leonardo Pierobon ◽  
Fredrik Haglind ◽  
Anna Stoppato
Keyword(s):  
Power Plant ◽  
Power System ◽  
Gas Turbine ◽  
Rise Time ◽  
Gas Turbines ◽  
Oil And Gas ◽  
Combined Cycle ◽  
Power Demand ◽  
Part Load ◽  
Exhaust Heat

When the Norwegian government introduced the CO2 tax for hydrocarbon fuels, the challenge became to improve the performance of off-shore power systems. An oil and gas platform typically operates on an island (stand-alone system) and the power demand is covered by two or more gas turbines. In order to improve the plant performance, a bottoming cycle unit can be added to the gas turbine topping module, thus constituting a combined cycle plant. This paper aims at developing and testing the numerical model simulating the part-load and dynamic behavior of a novel power system, composed of two gas turbines and a combined gas turbine coupled with an air bottoming cycle plant. The case study is the Draugen off-shore oil and gas platform, located in the North Sea, Norway. The normal electricity demand is 19 MW, currently covered by two gas turbines generating each 50% of the power demand, while the third turbine is on stand-by. During oil export operations the power demand increases up to 25 MW. The model of the new power plant proposed in this work is developed in the Modelica language using basic components acquired from ThermoPower, a library for power plant modelling. The dynamic model of the gas turbine and the air bottoming cycle turbogenerator includes dynamic equations for the combustion chamber, the shell-and-tube recuperator and the turbine shafts. Turbines are modelled by the Stodola equation and by a correlation between the isentropic efficiency and the non-dimensional flow coefficient. Compressors are modelled using quasi steady-state conditions by scaling the maps of axial compressors employing a similar design point. The recuperator, which recovers the exhaust heat from the gas turbine, is modelled using correlations relating the heat transfer coefficient and the pressure drop at part-load with the mass flow rate. Thermodynamic variables and dynamic metrics, such as the rise time and the frequency undershooting/ overshooting, are predicted. Considering a load ramp of 0.5 MW/s, an undershooting of 4.9% and an overshooting of 3.0% are estimated. The rise time is approximately 30 s. Moreover, findings suggest that decreasing the core weight of the recuperator leads to limiting the frequency fluctuations, thus minimizing the risk of failure of the power system.

Syngas Fuel Hybrid 45 MW GTCC/ORC Power Plant Using Modular 500 TPD Coal/Biomass Modular Pyrolytic Gasification

2010 ◽  
Author(s):  
Septimus van der Linden ◽  
Mark Wiley ◽  
Gary Williams ◽  
Roel Swart
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Diesel Fuel ◽  
Gas Turbines ◽  
Developing Economies ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Oxygen Plant ◽  
Gasification Process ◽  
Exhaust Heat

This paper presents a solution for developing economies where power shortages require power plants in the range of 30/50 MW or larger to support industrial facilities such as mining or industrial parks where natural gas is not available and where diesel fuel is expensive, but where coal is readily available. Recent developments with Pyrolytic gasification systems by Wiley Consulting, capable of modular 500tpd of coal or biomass, were investigated for power starved sub-Saharan African countries. This Gasifier does not require an oxygen plant and produces a Syngas that can be combusted in modified FR6B gas turbines. The Syngas needs to be compressed and the parasitic load is accommodated with steam injection for NOx control and power enhancement to power the fuel gas compressor. To simplify the exhaust heat power recovery, the Cascading Closed Loop Cycle (CCLC) Organic Rankine Cycle (ORC) system was integrated into this system, resulting in a nominal 45 MW coal or biomass power plant at altitudes over 1000m achieving 40%+ efficiency. Coal fired steam plant Rankine cycle was considered expensive and inefficient due to the requirements of low emissions as well as more than 70% of the fuel energy rejected in the condensing system. Using the Gas Turbine Brayton cycle to combust Synthesis Gas (produced by an innovative Pyrolytic and modular gasification process that did not need an oxygen plant) was considered a practical alternative, especially as the Gas Turbine is air cooled. To fully capture the value of the Syngas fuel, the Gas Turbine exhaust energy would be recovered in an ORC which avoided the use of water and provided excellent load following characteristics as well as the capability to turndown to 40% or lower loads. The criteria established for the power plant was to build and commission the plant in 24 months or less. This necessitated looking at available used and refurbished generating equipment. The modular Gasifier, already demonstrated as a 250 tpd system, could readily be scaled to 500 tpd coal or biomass with about the same footprint and dispatched in modules for fast installation. The availability of a used 38 MW class GT for refurbishment and modification to Syngas fuel combustion system allowed site installation within one year and the provision of emergency power using available diesel fuel. This paper will fully describe the 45 MWe Hybrid GT/ORC Combined Cycle power plant utilizing the innovative Pyrolytic coal gasification process as the fuel source for an efficient low emissions power supply.

scholarly journals Powering Ahead

2011 ◽  
Vol 133 (05) ◽  
pp. 30-33 ◽  
Author(s):  
Lee S. Langston
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Nuclear Power ◽  
Electrical Power ◽  
The United States ◽  
Combined Cycle ◽  
Electrical Power System ◽  
Efficient Technology ◽  
The Military

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.

Part-Load Operation of Gas Turbines Induced by Co-Gasification of Coal and Biomass in an Integrated Gasification Combined Cycle Power Plant

2021 ◽  
Author(s):  
Silvia Ravelli
Keyword(s):  
Power Plant ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Fuel Quality ◽  
Integrated Gasification Combined Cycle ◽  
Part Load ◽  
Wide Range ◽  
Integrated Gasification

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.

Performance Analysis of a Combined Cycle Power Plant Through Exergetic and Environmental Indices

2017 ◽  
Author(s):  
Edgar Vicente Torres González ◽  
Raúl Lugo Leyte ◽  
Martín Salazar Pereyra ◽  
Helen Denise Lugo Méndez ◽  
Miguel Toledo Velázquez ◽  
...  
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Environmental Indices ◽  
Combined Cycle Power Plant ◽  
Combustion Gases ◽  
Combined Cycle Plant ◽  
Exergetic Analysis ◽  
Gas Turbine Power Plant

In this paper is carried out a comparison between a gas turbine power plant and a combined cycle power plant through exergetic and environmental indices in order to determine performance and sustainability aspects of a gas turbine and combined cycle plant. First of all, an exergetic analysis of the gas turbine and the combined is carried out then the exergetic and environmental indices are calculated for the gas turbine (case A) and the combined cycle (case B). The exergetic indices are exergetic efficiency, waste exergy ratio, exergy destruction factor, recoverable exergy ratio, environmental effect factor and exergetic sustainability. Besides, the environmental indices are global warming, smog formation and acid rain indices. In the case A, the two gas turbines generate 278.4 MW; whereas 415.19 MW of electricity power is generated by the combined cycle (case B). The results show that exergetic sustainability index for cases A and B are 0.02888 and 0.1058 respectively. The steam turbine cycle improves the overall efficiency, as well as, the reviewed exergetic indexes. Besides, the environmental indices of the gas turbines (case A) are lower than the combined cycle environmental indices (case B), since the combustion gases are only generated in the combustion chamber.

Short-Term Optimization of a Combined Cycle Power Plant Integrated With an Inlet Air Conditioning Unit

2020 ◽  
Author(s):  
Weimar Mantilla ◽  
José García ◽  
Rafael Guédez ◽  
Alessandro Sorce
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Air Conditioning ◽  
Combined Cycle ◽  
Plant Performance ◽  
Mixed Integer ◽  
Environmental Load ◽  
Turbine Inlet ◽  
The Impact

Abstract Under new scenarios with high shares of variable renewable electricity, combined cycle gas turbines (CCGT) are required to improve their flexibility, in terms of ramping capabilities and part-load efficiency, to help balance the power system. Simultaneously, liberalization of electricity markets and the complexity of its hourly price dynamics are affecting the CCGT profitability, leading the need for optimizing its operation. Among the different possibilities to enhance the power plant performance, an inlet air conditioning unit (ICU) offers the benefit of power augmentation and “minimum environmental load” (MEL) reduction by controlling the gas turbine inlet temperature using cold thermal energy storage and a heat pump. Consequently, an evaluation of a CCGT integrated with this inlet conditioning unit including a day-ahead optimized operation strategy was developed in this study. To establish the hourly dispatch of the power plant and the operation mode of the inlet conditioning unit to either cool down or heat up the gas turbine inlet air, a mixed-integer linear optimization (MILP) was formulated using MATLAB, aiming to maximize the operational profit of the plant within a 24-hours horizon. To assess the impact of the proposed unit operating under this dispatch strategy, historical data of electricity and natural gas prices, as well as meteorological data and CO2 emission allowances price, have been used to perform annual simulations of a reference power plant located in Turin, Italy. Furthermore, different equipment capacities and parameters have been investigated to identify trends of the power plant performance. Lastly, a sensitivity analysis on market conditions to test the control strategy response was also considered. Results indicate that the inlet conditioning unit, together with the dispatch optimization, increases the power plant’s operational profit by achieving a wider operational range, particularly important during peak and off-peak periods. For the specific case study, it is estimated that the net present value of the CCGT integrated with the ICU is 0.5% higher than the power plant without the unit. In terms of technical performance, results show that the unit reduces the minimum environmental load by approximately 1.34% and can increase the net power output by 0.17% annually.

Combined Heat and Power: Gas Turbine Operational Flexibility

2013 ◽  
Author(s):  
James DiCampli
Keyword(s):  
Gas Turbine ◽  
Urban Areas ◽  
Gas Turbines ◽  
Heat Recovery ◽  
National Fire Protection Association ◽  
Combined Heat And Power ◽  
Combined Cycle ◽  
Electricity Production ◽  
Exhaust Heat ◽  
Gas Fuel

Combined heat and power (CHP) is an application that utilizes the exhaust heat generated from a gas turbine and converts it into a useful energy source for heating & cooling, or additional electric generation in combined cycle configurations. Compared to simple-cycle plants with no heat recovery, CHP plants emit fewer greenhouse gasses and other emissions, while generating significantly more useful energy per unit of fuel consumed. Clean plants are easier to permit, build and operate. Because of these advantages, projections show CHP capacity is expected to double and account for 24% of global electricity production by 2030. An aeroderivative power plant has distinct advantages to meet CHP needs. These include high thermal efficiency, low cost, easy installation, proven reliability, compact design for urban areas, simple operation and maintenance, fuel flexibility, and full power generation in a very short time period. There has been extensive discussion and analyses on modifying purge requirements on cycling units for faster dispatch. The National Fire Protection Association (NFPA) has required an air purge of downstream systems prior to startup to preclude potentially flammable or explosive conditions. The auto ignition temperature of natural gas fuel is around 800°F. Experience has shown that if the exhaust duct contains sufficient concentrations of captured gas fuel, and is not purged, it can ignite immediately during light off causing extensive damage to downstream equipment. The NFPA Boiler and Combustion Systems Hazards Code Committee have developed new procedures to safely provide for a fast-start capability. The change in the code was issued in the 2011 Edition of NFPA 85 and titled the Combustion Turbine Purge Credit. For a cycling plant and hot start conditions, implementation of purge credit can reduce normal start-to-load by 15–30 minutes. Part of the time saving is the reduction of the purge time itself, and the rest is faster ramp rates due to a higher initial temperature and pressure in the heat recovery steam generator (HRSG). This paper details the technical analysis and implementation of the NFPA purge credit recommendations on GE Power and Water aeroderivative gas turbines. This includes the hardware changes, triple block and double vent valve system (or drain for liquid fuels), and software changes that include monitoring and alarms managed by the control system.

Requirements for Gas Turbine Inlet Systems in Russia

2009 ◽  
Author(s):  
Tagir R. Nigmatulin ◽  
Vladimir E. Mikhailov
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Oil And Gas ◽  
Inlet System ◽  
Climate Zones ◽  
Russian Market ◽  
Turbine Inlet ◽  
Industrial Gas Turbines

Russian power generation, oil and gas businesses are rapidly growing. Installation of new industrial gas turbines is booming to fulfill the demand from economic growth. Russia is a unique country from the annual temperature variation point of view. Some regions may reach up to 100C. One of the biggest challenges for world producers of gas turbines in Russia is the ability to operate products at power plants during cold winters, when ambient temperature might be −60C for a couple of weeks in a row. The reliability and availability of the equipment during the cold season is very critical. Design of inlet systems and filter houses for the Russian market, specifically for northern regions, has a lot of specifics and engineering challenges. Joint Stock Company CKTI is the biggest Russian supplier of air intake systems for industrial gas turbines and axial-flow compressors. In 1969 this enterprise designed and installed the first inlet for the power plant Dagskaya GRES (State Regional Electric Power Plant) with the first 100MW gas-turbine which was designed and manufactured by LMZ. Since the late 1960s CKTI has designed and manufactured inlet systems for the world market and been the main supplier for the Russian market. During the last two years CKTI has designed inlet systems for a broad variety of gas turbine engines ranging from 24MW up to 110MW turbines which are used for power generation and as a mechanical drive for the oil and gas industry. CKTI inlet systems with filtering devices or houses are successfully used in different climate zones including the world’s coldest city Yakutsk and hot Nigeria. CKTI has established CTQs (Critical to quality) and requirements for industrial gas turbine inlet systems which will be installed in Russia in different climate zones for all types of energy installations. The last NPI project of the inlet system, including a nonstandard layout, was done for a small gas-turbine engine which is installed on a railway cart. This arrangement is designed to clean railway lines with the exhaust jet in a quarry during the winter. The design of the inlet system with efficient multistage compressor extraction for deicing, dust and snow resistance has an interesting solution. The detailed description of challenges, weather requirements, calculations, losses, and design methodologies to qualify the system for tough requirements, are described in the paper.

HRSG Duct Firing Revisited

2018 ◽  
Author(s):  
S. Can Gülen
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Fossil Fuel ◽  
Heat Rate ◽  
Combined Cycle ◽  
Efficiency Improvement ◽  
Combined Cycle Power Plant

Duct firing in the heat recovery steam generator (HRSG) of a gas turbine combined cycle power plant is a commonly used method to increase output on hot summer days when gas turbine airflow and power output lapse significantly. The aim is to generate maximum possible power output when it is most needed (and, thus, more profitable) at the expense of power plant heat rate. In this paper, using fundamental thermodynamic arguments and detailed heat and mass balance simulations, it will be shown that, under certain boundary conditions, duct firing in the HRSG can be a facilitator of efficiency improvement as well. When combined with highly-efficient aeroderivative gas turbines with high cycle pressure ratios and concomitantly low exhaust temperatures, duct firing can be utilized for small but efficient combined cycle power plant designs as well as more efficient hot-day power augmentation. This opens the door to efficient and agile fossil fuel-fired power generation opportunities to support variable renewable generation.

Gas Turbine Part Load Performance Testing: Comparison of Test Methodologies

2008 ◽  
Author(s):  
Thomas P. Schmitt ◽  
Herve Clement
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Guide Vane ◽  
Performance Testing ◽  
Load Level ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Performance Guarantee ◽  
Part Load ◽  
Advantages And Disadvantages

Current trends in usage patterns of gas turbines in combined cycle applications indicate a substantial proportion of part load operation. Commensurate with the change in operating profile, there has been an increase in the propensity for part load performance guarantees. When a project is structured such that gas turbines are procured as equipment-only from the manufacturer, there is occasionally a gas turbine part load performance guarantee that coincides with the net plant combined cycle part load performance guarantee. There are several methods by which to accomplish part load gas turbine performance testing. One of the more common methods is to operate the gas turbine at the specified load value and construct correction curves at constant load. Another common method is to operate the gas turbine at a specified load percentage and construct correction curves at constant percent load. A third method is to operate the gas turbine at a selected load level that corresponds to a predetermined compressor inlet guide vane (IGV) angle. The IGV angle for this third method is the IGV angle that is needed to achieve the guaranteed load at the guaranteed boundary conditions. The third method requires correction curves constructed at constant IGV, just like base load correction curves. Each method of test and correction embodies a particular set of advantages and disadvantages. The results of an exploration into the advantages and disadvantages of the various performance testing and correction methods for part load performance testing of gas turbines are presented. Particular attention is given to estimates of the relative uncertainty for each method.

Outline of Plan for Advanced Reheat Gas Turbine

1981 ◽  
Vol 103 (4) ◽  
pp. 772-775 ◽  
Author(s):  
Akifumi Hori ◽  
Kazuo Takeya
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Axial Flow ◽  
Combined Cycle ◽  
Research Association ◽  
Major Objective ◽  
Engineering Research ◽  
Set Up

A new reheat gas turbine system is being developed as a national project by the “Engineering Research Association for Advanced Gas Turbines” of Japan. The machine consists of two axial flow compressors, three turbines, intercooler, combustor and reheater. The pilot plant is expected to go into operation in 1982, and a prototype plant will be set up in 1984. The major objective of this reheat gas turbine is application to a combined cycle power plant, with LNG burning, and the final target of combined cycle thermal efficiency is to be 55 percent (LHV).

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