Thermodynamic analysis of small-scale externally fired gas turbines and combined cycles using turbo-compound components for energy generation from solid biomass

2018 ◽  
Vol 166 ◽  
pp. 648-662 ◽  
Author(s):  
Riccardo Amirante ◽  
Pietro De Palma ◽  
Elia Distaso ◽  
Paolo Tamburrano
2017 ◽  
Vol 129 ◽  
pp. 891-898 ◽  
Author(s):  
R. Amirante ◽  
P. De Palma ◽  
E. Distaso ◽  
A.M. Pantaleo ◽  
P. Tamburrano

Author(s):  
Ahti Jaatinen-Värri ◽  
Jari Backman ◽  
Juha Honkatukia ◽  
Matti Malkamäki

Throughout the world there is pressure to increase distributed energy generation. Driving factors include for example political and environmental concerns in developed countries and reliability in places where centralized grid does not either exist or is too unreliable. The energy generation based on renewable fuels such as biogas is also usually decentralized. To answer this demand, the number of small-scale gas turbine combined heat and power (CHP) installations have increased. Due to its nature, the required power output of distributed generation is highly variable. The power output of decentralized power plant needs to follow the local consumption power need and thus it needs to be efficiently controlled. Therefore, the requirement for variable output necessitates that small-scale gas turbines are often run at part-loads. Previously, most of the installed small-scale gas turbines have been single-spool units with either fixed or variable speed shafts. Control schemes and part-load performance are somewhat different for the two setups. Recently, a two-spool gas turbine where the spools can be controlled independently has been proposed as a feasible alternative. The possibility to produce the desired power output with two spools, both having their own generator, which can be controlled independently of each other, offers significantly more possibilities for the control. Therefore, it might also offer better part-load performance. In this paper, the control schemes of three different small-scale gas turbines are compared. Especially, the part-load electrical efficiency is studied. The studied gas turbines are: a single-spool fixed speed, a single-spool variable speed driven, and a two-spool variable speed driven gas turbine. The part-load performance of different machines is studied and then compared against each other. Furthermore, some estimations are given on how the part-load performance of each machine fares against certain load profiles.


Author(s):  
Frank Delattin ◽  
Svend Bram ◽  
Jacques De Ruyck

Power production from biomass can occur through external combustion (e.g. steam cycles, Organic Rankine Cycles, Stirling engines), or internal combustion after gasification or pyrolysis (e.g. gas engines, IGCC). External combustion has the disadvantage of delivering limited conversion efficiencies (max 35%). Internal combustion has the potential of high efficiencies, but it always needs a severe and mostly problematic gas cleaning. The present article proposes an alternative route where advantages of external firing are combined with potential high efficiency of combined cycles through co-utilization of natural gas and biomass. Biomass is burned to provide heat for partial reforming of the natural gas feed. In this way, biomass energy is converted into chemical energy contained in the produced syngas. Waste heat from the reformer and from the biomass combustor is recovered through a waste heat recovery system. It has been shown in previous papers that in this way biomass can replace up to 5% of the natural gas in steam injected gas turbines and combined cycles, whilst maintaining high efficiencies [1,2]. The present paper proposes the application of this technique as retrofit of an existing combined cycle power plant (Drogenbos, Belgium) where 1% of the natural gas input would be replaced by wood pellets. This represents an installed biomass capacity of 5 MWth from biomass which could serve as a small scale demonstration. The existing plant cycle is first simulated and validated. The simulated cycle is next adapted to partially run on biomass and a retrofit power plant cycle layout is proposed.


Author(s):  
Seyed Aliakbar Mirmohammadi ◽  
Mohammad Reza Behi ◽  
Alexander B. Suma ◽  
Björn E. Palm

Renewable energy continues to attract much interest due to the depletion of fossil fuels and unsettled political disputes. This study aims to evaluate the current status of energy generation on the campus of Eindhoven University of Technology (TU/e). Furthermore, it looks for ways for the TU/e to improve sustainability by finding and proposing alternative solutions. Therefore, a broad scope of various renewable energy sources (RES) has been investigated. From many aspects, the analysis of RES proves that biomass is the most appropriate source of renewable energy for the TU/e campus. Thus, the capability of harvestable biomass fuel in energy generation throughout a year has been investigated for this project, and it has been concluded that solid biomass waste from the campus can provide 1314 MWh heat load annually. In order to achieve as much energy from biomass as possible, a combined heat and power unit (CHP), in order to produce both heat and electricity for new student houses on the campus, has been modeled. Finally, the project results show that a small-scale CHP cycle is capable of producing 366 MWh electricity, as well as 772 MWh heat, annually.


Author(s):  
Matti Malkamäki ◽  
Ahti Jaatinen-Värri ◽  
Antti Uusitalo ◽  
Aki Grönman ◽  
Juha Honkatukia ◽  
...  

Decentralized electricity and heat production is a rising trend in small-scale industry. There is a tendency towards more distributed power generation. The decentralized power generation is also pushed forward by the policymakers. Reciprocating engines and gas turbines have an essential role in the global decentralized energy markets and improvements in their electrical efficiency have a substantial impact from the environmental and economic viewpoints. This paper introduces an intercooled and recuperated three stage, three-shaft gas turbine concept in 850 kW electric output range. The gas turbine is optimized for a realistic combination of the turbomachinery efficiencies, the turbine inlet temperature, the compressor specific speeds, the recuperation rate and the pressure ratio. The new gas turbine design is a natural development of the earlier two-spool gas turbine construction and it competes with the efficiencies achieved both with similar size reciprocating engines and large industrial gas turbines used in heat and power generation all over the world and manufactured in large production series. This paper presents a small-scale gas turbine process, which has a simulated electrical efficiency of 48% as well as thermal efficiency of 51% and can compete with reciprocating engines in terms of electrical efficiency at nominal and partial load conditions.


Author(s):  
N. Courtois ◽  
F. Ebacher ◽  
P. K. Dubois ◽  
N. Kochrad ◽  
C. Landry ◽  
...  

The use of ceramics in gas turbines potentially allows for very high cycle efficiency and power density, by increasing operating temperatures. This is especially relevant for sub-megawatt gas turbines, where the integration of complex blade cooling greatly affects machine capital cost. However, ceramics are brittle and prone to fragile, catastrophic failure, making their current use limited to static and low-stress parts. Using the inside-out ceramic turbine (ICT) configuration solves this issue by converting the centrifugal blade loading to compressive stress, by using an external high-strength carbon-polymer composite rim. This paper presents a superalloy cooling system designed to protect the composite rim and allow it to withstand operating temperatures up to 1600 K. The cooling system was designed using one-dimensional (1D) models, developed to predict flow conditions as well as the temperatures of its critical components. These models were subsequently supported with computational fluid dynamics and used to conduct a power scalability study on a single stage ICT. Results suggest that the ICT configuration should achieve a turbine inlet temperature (TIT) of 1600 K with a composite rim cooling-to-main mass flow rate ratio under 5.2% for power levels above 350 kW. A proof of concept was performed by experimental validation of a small-scale 15 kW prototype, using a commercially available bismaleimide-carbon (BMI-carbon) composite rim and Inconel® 718 nickel-based alloy. The combination of numerical and experimental results show that the ICT can operate at a TIT of 1100 K without damage to the composite rim.


Author(s):  
Fabrizio Reale ◽  
Vincenzo Iannotta ◽  
Raffaele Tuccillo

The primary need of reducing pollutant and greenhouse gas emissions has led to new energy scenarios. The interest of research community is mainly focused on the development of energy systems based on renewable resources and energy storage systems and smart energy grids. In the latter case small scale energy systems can become of interest as nodes of distributed energy systems. In this context micro gas turbines (MGT) can play a key role thanks to their flexibility and a strategy to increase their overall efficiency is to integrate gas turbines with a bottoming cycle. In this paper the authors analyze the possibility to integrate a MGT with a super critical CO2 Brayton cycle turbine (sCO2 GT) as a bottoming cycle (BC). A 0D thermodynamic analysis is used to highlight opportunities and critical aspects also by a comparison with another integrated energy system in which the waste heat recovery (WHR) is obtained by the adoption of an organic Rankine cycle (ORC). While ORC is widely used in case of middle and low temperature of the heat source, s-CO2 BC is a new method in this field of application. One of the aim of the analysis is to verify if this choice can be comparable with ORC for this operative range, with a medium-low value of exhaust gases and very small power values. The studied MGT is a Turbec T100P.


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