Optimizing Natural Gas Combined Cycle Part Load Operation

2019 ◽  
Author(s):  
Robert Flores ◽  
Jack Brouwer
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Combined Cycle ◽  
University Of California ◽  
Inlet Guide Vane ◽  
Outlet Temperature ◽  
Part Load ◽  
Carbon Neutrality ◽  
Natural Gas Combined Cycle ◽  
The University

Abstract The University of California, Irvine (UCI) uses a 19 MW natural gas combined cycle (NGCC) to provide nearly all campus energy requirements. Meanwhile, the University of California system has committed to achieving carbon neutrality at all facilities by 2025. This has resulted in an influx of new energy efficiency and onsite solar generation, increasing the duration of NGCC part load operation. In addition, the shift towards carbon neutrality has resulted in the pursuit of renewable natural gas via anaerobic digestion to replace conventional fossil fuels. The combination of other sources of renewable generation and the shift towards more expensive fuels has created the need to boost NGCC part load performance. This work focuses on the methods used at UCI to explore the NGCC operating space in order to optimize part-load performance. In this work, a physical gas turbine and heat recovery steam generator model are developed and used with an exhaustive search optimization method to predict maximum part load plant efficiency. NGCC control elements considered in this work include gas turbine inlet guide vane modulation and changing combustor outlet temperature. This optimization was also used to explore replacing the current engine with a two-shaft or smaller gas turbine. Results indicate that there are some possible benefits with increased modulation of inlet guide vanes, but the largest efficiency gains are achieved when allowing the compressor to operate at variable speed. Shifting towards a smaller engine could also enable more consistent full power operation, but must be paired with additional resources in order to meet the campus demand.

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.

scholarly journals Exergetic Analysis of a Natural Gas Combined-Cycle Power Plant with a Molten Carbonate Fuel Cell for Carbon Capture

2022 ◽  
Vol 14 (1) ◽  
pp. 533
Author(s):  
Alberto Fichera ◽  
Samiran Samanta ◽  
Rosaria Volpe
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Carbon Capture ◽  
Combined Cycle ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Combined Cycle Power Plant ◽  
Natural Gas Combined Cycle ◽  
Exergetic Analysis

This study aims to propose the repowering of an existing Italian natural-gas fired combined cycle power plant through the integration of Molten Carbonate Fuel Cells (MCFC) downstream of the gas turbine for CO2 capture and to pursuit an exergetic analysis of the two schemes. The flue gases of the turbine are used to feed the cathode of the MCFC, where CO2 is captured and transported to the anode while generating electric power. The retrofitted plant produces 787.454 MW, in particular, 435.29 MW from the gas turbine, 248.9 MW from the steam cycle, and 135.283 MW from the MCFC. Around 42.4% of the exergy destruction has been obtained, the majority belonging to the combustion chamber and, in minor percentages, to the gas turbine and the MCFC. The overall net plant efficiency and net exergy efficiency are estimated to be around 55.34 and 53.34%, respectively. Finally, the specific CO2 emission is around 66.67 kg/MWh, with around 2 million tons of carbon dioxide sequestrated.

Reheat Air-Brayton Combined Cycle Power Conversion Off-Nominal and Transient Performance

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Charalampos Andreades ◽  
Lindsay Dempsey ◽  
Per F. Peterson
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Nuclear Power ◽  
Power Plants ◽  
Power Conversion ◽  
Companion Paper ◽  
Combined Cycle ◽  
Natural Gas Combined Cycle ◽  
Reference Design ◽  
Molten Fluoride

Because molten fluoride salts can deliver heat at temperatures above 600 °C, they can be used to couple nuclear and concentrating solar power heat sources to reheat air combined cycles (RACC). With the open-air configuration used in RACC power conversion, the ability to also inject natural gas or other fuel to boost power at times of high demand provides the electric grid with contingency and flexible capacity while also increasing revenues for the operator. This combination provides several distinct benefits over conventional stand-alone nuclear power plants and natural gas combined cycle and peaking plants. A companion paper discusses the necessary modifications and issues for coupling an external heat source to a conventional gas turbine and provides two baseline designs (derived from the GE 7FB and Alstom GT24). This paper discusses off-nominal operation, transient response, and start-up and shutdown using the GE 7FB gas turbine as the reference design.

Design-point and part-load considerations for natural gas combined cycle plants with post combustion capture

2012 ◽  
Vol 11 ◽  
pp. 271-282 ◽  
Author(s):  
Kristin Jordal ◽  
Paul Andreas Marchioro Ystad ◽  
Rahul Anantharaman ◽  
Actor Chikukwa ◽  
Olav Bolland
Keyword(s):  
Natural Gas ◽  
Combined Cycle ◽  
Design Point ◽  
Part Load ◽  
Natural Gas Combined Cycle

Using Dynamic Simulation to Evaluate Attemperator Operation in a Natural Gas Combined Cycle With Duct Burners in the Heat Recovery Steam Generator

2017 ◽  
Author(s):  
Eric Liese ◽  
Stephen E. Zitney
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Saturation Temperature ◽  
Control Valve ◽  
Pressure Control ◽  
Combined Cycle ◽  
Training Simulator ◽  
Natural Gas Combined Cycle ◽  
Loading And Unloading ◽  
Pressure Control Valve

A generic training simulator of a natural gas combined cycle was modified to match operations at a real plant. The objective was to use the simulator to analyze cycling operations of the plant. Initial operation of the simulator revealed the potential for saturation conditions in the final high pressure superheater as the attemperator tried to control temperature at the superheater outlet during gas turbine loading and unloading. Subsequent plant operational data confirmed simulation results. Multiple simulations were performed during loading and unloading of the gas turbine to determine operational strategies that prevented saturation and increased the approach to saturation temperature. The solutions included changes to the attemperator temperature control setpoints and strategic control of the steam turbine inlet pressure control valve.

Using Molten Carbonate Fuel Cell Systems for CO2 With a Natural Gas Combined Cycle Operating at Part Load

2019 ◽  
Author(s):  
Robert Flores ◽  
Jack Brouwer
Keyword(s):  
Fuel Cell ◽  
Power Plant ◽  
Natural Gas ◽  
Carbon Capture ◽  
Combined Cycle ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Part Load ◽  
Natural Gas Combined Cycle ◽  
Carbonate Fuel Cell

Abstract Traditional carbon capture technology has been shown to effectively capture emissions, but at a cost of reducing power plant output. Molten carbonate fuel cell technology (MCFC) has the potential to be able to concentrate plant carbon emissions into a gas stream that is suitable for storage while boosting total plant power output. When considering this type of technology, the original purpose and function of the power plant must be considered. In particular, gas turbines (GT) based natural gas combined cycle (NGCC), which are capable of dynamic load following operation, are likely to need to maintain operational flexibility. This work explores the retrofit of an existing GT with MCFC technology for carbon capture when the plant is operated at part load. Physical models for major plant components are built and used to select optimal operating set points such that operating cost is minimized. Special attention is given to ensuring feasible operation across all engine components. The results show MCFC operational parameters that minimize change in fuel cell operating conditions when the gas turbine is operated at part load.

Natural gas combined cycle with exhaust gas recirculation and CO2 capture at part-load operation

2019 ◽  
Vol 92 (2) ◽  
pp. 370-381 ◽  
Author(s):  
Agustín Moisés Alcaráz-Calderon ◽  
Maria Ortencia González-Díaz ◽  
Ángel Mendez ◽  
Jose Miguel González-Santaló ◽  
Abigail González-Díaz
Keyword(s):  
Natural Gas ◽  
Co2 Capture ◽  
Exhaust Gas Recirculation ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Part Load ◽  
Natural Gas Combined Cycle ◽  
Gas Recirculation

Using Dynamic Simulation to Evaluate Attemperator Operation in a Natural Gas Combined Cycle With Duct Burners in the Heat Recovery Steam Generator

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Eric Liese ◽  
Stephen E. Zitney
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Saturation Temperature ◽  
Control Valve ◽  
Pressure Control ◽  
Combined Cycle ◽  
Training Simulator ◽  
Natural Gas Combined Cycle ◽  
Loading And Unloading ◽  
Pressure Control Valve

A generic training simulator of a natural gas combined cycle (NGCC) was modified to match operations at a real plant. The objective was to use the simulator to analyze cycling operations of the plant. Initial operation of the simulator revealed the potential for saturation conditions in the final high pressure superheater (HPSH) as the attemperator tried to control temperature at the superheater outlet during gas turbine loading and unloading. Subsequent plant operational data confirmed simulation results. Multiple simulations were performed during loading and unloading of the gas turbine to determine operational strategies that prevented saturation and increased the approach to saturation temperature. The solutions included changes to the attemperator temperature control setpoints and strategic control of the steam turbine (ST) inlet pressure control valve.

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