Abstract
The aim of the project was to perform a pre-study of the potential to introduce a biofired gas turbine into the pre-heater train of a district heating plant. The incentive for the work is the desire (and political drivers) to increase bio-fuel usage in heat and power production. Sweden has also ratified the EU treaty of having 20 percent renewable in the system before 2020. There are several options at the hand but locally produced biofuels from either gasification or biological processes can be fired in a gas turbine. The size of the gas turbine is limited by shear size of the fuel plant and raw-material transport issues. Today, the maximum electrical efficiency for large-scale advanced plants is on the order of 60 percent. This level is, however, not feasible for smaller size units and one can expect much lower levels. Another possibility is to re-power an existing plant and use the exhaust heat from the gas turbine. Either to produce steam in a heat recovery steam generator, heat boiler combustion air (and variants) or to reduce pre-heater extraction through by-passing the pre-heaters. Previous studies have shown that one could expect very high efficiency levels if the heat could be
More>>
Citation Formats
Genrup, Magnus, and Jonshagen, Klas.
Integration of bio-fired gas turbines in combined heat and power generation; Integrering av biogaseldad gasturbin i kraftvaermeanlaeggning.
Sweden: N. p.,
2011.
Web.
Genrup, Magnus, & Jonshagen, Klas.
Integration of bio-fired gas turbines in combined heat and power generation; Integrering av biogaseldad gasturbin i kraftvaermeanlaeggning.
Sweden.
Genrup, Magnus, and Jonshagen, Klas.
2011.
"Integration of bio-fired gas turbines in combined heat and power generation; Integrering av biogaseldad gasturbin i kraftvaermeanlaeggning."
Sweden.
@misc{etde_1010825,
title = {Integration of bio-fired gas turbines in combined heat and power generation; Integrering av biogaseldad gasturbin i kraftvaermeanlaeggning}
author = {Genrup, Magnus, and Jonshagen, Klas}
abstractNote = {The aim of the project was to perform a pre-study of the potential to introduce a biofired gas turbine into the pre-heater train of a district heating plant. The incentive for the work is the desire (and political drivers) to increase bio-fuel usage in heat and power production. Sweden has also ratified the EU treaty of having 20 percent renewable in the system before 2020. There are several options at the hand but locally produced biofuels from either gasification or biological processes can be fired in a gas turbine. The size of the gas turbine is limited by shear size of the fuel plant and raw-material transport issues. Today, the maximum electrical efficiency for large-scale advanced plants is on the order of 60 percent. This level is, however, not feasible for smaller size units and one can expect much lower levels. Another possibility is to re-power an existing plant and use the exhaust heat from the gas turbine. Either to produce steam in a heat recovery steam generator, heat boiler combustion air (and variants) or to reduce pre-heater extraction through by-passing the pre-heaters. Previous studies have shown that one could expect very high efficiency levels if the heat could be utilized in the feed water to the boiler. This is typically coupled to the admission pressure level and super-critical plant may have feed water temperature exceeding 300 deg C. The aim of this project was to investigate the potential from introducing this technology into a certain typical Swedish/Nordic turbine based district heating plant. A typical plant has modest admission data (compared to an ultra super-critical plant), hence lower final feed water temperature. A lower final temperature makes it more troublesome to effectively use the exhaust heat from the gas turbine. A further improvement is possible by introducing reheat. There are several practical limitations, where the most severe is the need to extract the full turbine flow and induce it after the reheater. The only practical way is to use the cross-over pipe. The cross-over pressure level is adapted to optimize the loading distribution between the high- and low pressure turbine rather than providing a suitable reheat pressure. Hence, two limits to address in the present prestudy. This work is based on the plant in Enkoeping and two suitable gas turbine candidates were investigated in this study. One engine with a low exhaust temperature and an engine with rather high exhaust temperature were chosen for this study. The first engine is the Solar Mercury 50 and the second candidate is Siemens SGT-100. The result indicates that the marginal efficiency is on the order of 45 percent for a twin Mercury 50 set (including reheat). The hotter Siemens engine reaches approximately 50 percent, when the steam is reheated to 320 deg C in the cross-over pipe. The final feed water temperature of 205 deg C poses a strong limiting factor for the reachable efficiency levels. Another issue is the steam turbine axial trust, where one can expect changes when the turbine is operated under the described conditions. The results, however, indicates that there actually is a relief in trust bearing loading. [Key to report nomenclature and abbreviations:] All gas turbine related performance parameters are related to the standard ISO condition. The work is based on cycle off-design modeling on several levels and numerical optimization. The chosen programs are IPSEpro and Siemens in-house (proprietary) steam turbine and cycle design system. The LTH cycle off-design model has been calibrated against real plant data and shows good agreement when compared. The Siemens tool has mainly been used to verify the LTH-model and calculate the change in trust loading. The latter was initially thought as the limiting factor, but the work indicates that the chosen combinations should be possible to realize. The Siemens tool is based on a detailed stage-by-stage approach and has initially been used to design the turbine. The trust calculation is quite involved and includes flow momentum change, pressure differences (including radial equilibrium) over blades, shrouds and discs. Each presented cycle configuration has been optimized, using a generic algorithm, searching maximum steam cycle power increment while keeping realistic limitations. Such limitations are: feed pump cavitations issues when changing operating modes, subcooled condensate for efficient dearation and thrust bearing loading. The actual optimization runs have been set to optimize the flow distribution between the plant heaters (i.e. high- and low pressure) and the bio-fired gas turbine heat recovery generator. The gas turbines have been modeled using 'black box' approach for the engines except for the flue gas flow and composition. For the latter, realistic values have been calculated and used in the analysis}
place = {Sweden}
year = {2011}
month = {Jan}
}
title = {Integration of bio-fired gas turbines in combined heat and power generation; Integrering av biogaseldad gasturbin i kraftvaermeanlaeggning}
author = {Genrup, Magnus, and Jonshagen, Klas}
abstractNote = {The aim of the project was to perform a pre-study of the potential to introduce a biofired gas turbine into the pre-heater train of a district heating plant. The incentive for the work is the desire (and political drivers) to increase bio-fuel usage in heat and power production. Sweden has also ratified the EU treaty of having 20 percent renewable in the system before 2020. There are several options at the hand but locally produced biofuels from either gasification or biological processes can be fired in a gas turbine. The size of the gas turbine is limited by shear size of the fuel plant and raw-material transport issues. Today, the maximum electrical efficiency for large-scale advanced plants is on the order of 60 percent. This level is, however, not feasible for smaller size units and one can expect much lower levels. Another possibility is to re-power an existing plant and use the exhaust heat from the gas turbine. Either to produce steam in a heat recovery steam generator, heat boiler combustion air (and variants) or to reduce pre-heater extraction through by-passing the pre-heaters. Previous studies have shown that one could expect very high efficiency levels if the heat could be utilized in the feed water to the boiler. This is typically coupled to the admission pressure level and super-critical plant may have feed water temperature exceeding 300 deg C. The aim of this project was to investigate the potential from introducing this technology into a certain typical Swedish/Nordic turbine based district heating plant. A typical plant has modest admission data (compared to an ultra super-critical plant), hence lower final feed water temperature. A lower final temperature makes it more troublesome to effectively use the exhaust heat from the gas turbine. A further improvement is possible by introducing reheat. There are several practical limitations, where the most severe is the need to extract the full turbine flow and induce it after the reheater. The only practical way is to use the cross-over pipe. The cross-over pressure level is adapted to optimize the loading distribution between the high- and low pressure turbine rather than providing a suitable reheat pressure. Hence, two limits to address in the present prestudy. This work is based on the plant in Enkoeping and two suitable gas turbine candidates were investigated in this study. One engine with a low exhaust temperature and an engine with rather high exhaust temperature were chosen for this study. The first engine is the Solar Mercury 50 and the second candidate is Siemens SGT-100. The result indicates that the marginal efficiency is on the order of 45 percent for a twin Mercury 50 set (including reheat). The hotter Siemens engine reaches approximately 50 percent, when the steam is reheated to 320 deg C in the cross-over pipe. The final feed water temperature of 205 deg C poses a strong limiting factor for the reachable efficiency levels. Another issue is the steam turbine axial trust, where one can expect changes when the turbine is operated under the described conditions. The results, however, indicates that there actually is a relief in trust bearing loading. [Key to report nomenclature and abbreviations:] All gas turbine related performance parameters are related to the standard ISO condition. The work is based on cycle off-design modeling on several levels and numerical optimization. The chosen programs are IPSEpro and Siemens in-house (proprietary) steam turbine and cycle design system. The LTH cycle off-design model has been calibrated against real plant data and shows good agreement when compared. The Siemens tool has mainly been used to verify the LTH-model and calculate the change in trust loading. The latter was initially thought as the limiting factor, but the work indicates that the chosen combinations should be possible to realize. The Siemens tool is based on a detailed stage-by-stage approach and has initially been used to design the turbine. The trust calculation is quite involved and includes flow momentum change, pressure differences (including radial equilibrium) over blades, shrouds and discs. Each presented cycle configuration has been optimized, using a generic algorithm, searching maximum steam cycle power increment while keeping realistic limitations. Such limitations are: feed pump cavitations issues when changing operating modes, subcooled condensate for efficient dearation and thrust bearing loading. The actual optimization runs have been set to optimize the flow distribution between the plant heaters (i.e. high- and low pressure) and the bio-fired gas turbine heat recovery generator. The gas turbines have been modeled using 'black box' approach for the engines except for the flue gas flow and composition. For the latter, realistic values have been calculated and used in the analysis}
place = {Sweden}
year = {2011}
month = {Jan}
}