Flexibility is key to the future success of gas turbines for power generation. As renewable energy becomes more widely used the need for reliable, flexible standby power generation will increase. Gas turbines which are able to operate efficiently and in emissions compliance from extended low load to base load will have a significant advantage in meeting this need. Fuel costs and availability are of increasing concern. A gas turbine which is able to flexibly operate with a wide range of fuels, without the need for a diluent such as water or nitrogen, will provide added value to the operators of these machines. Carbon emissions are also of growing environmental concern, and the abatement of such emissions is likely to become of increasing monetary value. A fuel flexible combustor able to operate flexibly on both decarbonized fuel and natural gas will be well positioned to take commercial advantage of the situation. A combustion system is described and demonstrated which meets the goals set forth above. The system is simply retrofittable into existing E/F-class frame machines. The combustor is comprised of a dry lean premixed system without the need for diluents to control emissions. The operating principle of the new combustor is described. A full scale rig test program was undertaken to validate the new design and these results are presented. Results are shown with low emissions operation at 15–25% engine load. Combustor performance with a range of fuel blends up to 60% hydrogen, all with emissions below 9ppm of NOx and CO, is presented.

Flexibility is key to the future success of natural gas fired power generation. As renewable energy becomes more widely used, the need for reliable, flexible generation will increase. As such, gas turbines capable of operating efficiently and in emissions compliance from extended low load to full load will have a significant advantage. A wider range of gas fuels, including shale gas and refinery/industrial byproduct gas, is becoming increasingly available, with the opportunity to further reduce the cost of electricity. A combustion system capable of operating with wider ranges of heavy hydrocarbons, hydrogen and inerts will have an advantage to accommodate the future fuel gas trends and provide value to gas turbine operators. The FlameSheet™ combustor incorporates a novel dual zone burn system to address operational and fuel flexibility. It provides low emissions, extended turndown and fuel flexibility. FlameSheetTM is simply retrofittable into existing installed E/F-class heavy duty gas turbines and is designed to meet the energy market drivers set forth above. The operating principle of the new combustor is described, and details of a full scale high pressure rig test and engine validation program are discussed, providing insight on rig and engine emissions, as well as combustion dynamics performance. The FlameSheetTM implementation and validation results on a General Electric 7FA heavy duty gas turbine operating in a combined cycle power plant is discussed with emphasis on operational profile optimization to accommodate the heat recovery steam generator (HRSG), while substantially increasing the gas turbine normal operating load range.

Flexibility is key to the future success of natural gas fired power generation. As renewable energy sources continue their penetration of the global energy market, the need for reliable, flexible generation will increase. Gas turbines equipped with a fuel flexible combustion system allowing the capability to extend in-emissions-compliance turndown limit, will have a significant advantage supporting todays and future energy market demand. The FlameSheet™ combustor incorporates a novel dual zone burn system to address operational and fuel flexibility with low emissions and extended turndown. FlameSheet™ is simply retrofittable into existing installed E/F-class heavy duty gas turbines and is designed to meet the energy market drivers set forth above. The operating principle of the new combustor is briefly described, and details of implementation and extended validation results on two General Electric 7FA heavy duty gas turbines operating in a combined cycle power plant since 2015 with over 36,600hrs of uninterrupted commercial operation is discussed, with special focus on operational profile optimization to accommodate the heat recovery steam generator (HRSG), while substantially increasing the gas turbine normal operating load range. Emphasis is also provided on performance assessment, combustion and downstream hot gas path component inspection and durability assessment after 16,600 hours of operation in a 7FA gas turbine.

Renewables proliferation in the energy market is driving the need for flexibility in gas fired power plants to enable a wider and emissions compliant operability range. The ability for a gas fired plant to peak fire while maintaining emissions compliance, full life interval capability, improved simple and combined cycle heat rate and the ability to achieve extended turndown, positions a gas fired asset to benefit from an improved capacity factor, and overall economic viability in an increasingly renewables’ dependent energy market. The low pressure drop FlameSheet™ combustor variant’s implementation alongside PSM’s Gas Turbine Optimization Package (GTOP3.1) on a commercially operating frame 7FA heavy duty gas turbine in 2018 and as introduced in GT2019-91647, is presented with emphasis on extended validation of operational and emissions/tuning performance at different ambient conditions, higher peak firing and minimum load after one year of continuous commercial operation. The output and heat rate improvement achieved with the FlameSheet™/GTOP3.1 conversion thus enabling improved capacity is also discussed. As shale gas continue to grow as a dominant source of the U.S Natural gas supply, the need for fuel flexible combustion systems enabling tolerance to higher ethane/ethylene concentrations associated with Shale gas is required for improved operability. The adverse impact and means to mitigate such higher ethane/ethylene content on standard F-Class heavy duty combustion systems is also presented as part of said FlameSheet™/GTOP 3.1 conversion.

As renewable energy sources continue their global energy market penetration, new natural gas fired power plant installations have decreased significantly. The reduction in new installed capacity has increased pressure on operators to profitably maintain and expand their existing fleet capability. Retrofitting existing gas turbines to increase baseload power output, expand fuel flexibility and provide a wider operating load range are key natural gas fired power plant market demands. The FlameSheet™ combustor system addresses these considerations with a novel “dual-zone burn system” design that reduces emissions, increases fuel flexibility and reduces pressure losses to improve thermal cycle efficiency. The present work presents the results of FlameSheet™ installations into GE 7F.03 heavy duty gas turbines at two commercial sites. The first installation combined FlameSheet™ with PSM’s Gas Turbine Optimization Package (GTOP) to provide higher output through a combination of lower combustor pressure drop, higher mass flows and an increase in firing temperature, while maintaining sub-9ppm NOx emissions across the expanded operating range. Results are also presented for a second site on a unit that operates with up to 5% hydrogen blend into the baseline natural gas, where a reduction in NOx to sub-4 ppm levels at a typical 7F.03 baseload point has been safely and reliably achieved. Both results continue to demonstrate that fuel flexibility and expanded operational windows are possible to “future proof” existing gas turbine installations at a fraction of the cost of a new unit installation.