scholarly journals Cycle-Tempo Simulation of Ultra-Micro Gas Turbine Fueled by Producer Gas Resulting from Leaf Waste Gasification

2021 ◽  
Vol 24 (3) ◽  
pp. 14-20
Author(s):  
Fajri Vidian ◽  
◽  
Putra Anugrah Peranginangin ◽  
Muhamad Yulianto ◽  
◽  
...  

Leaf waste has the potential to be converted into energy because of its high availability both in the world and Indonesia. Gasification is a conversion technology that can be used to convert leaves into producer gas. This gas can be used for various applications, one of which is using it as fuel for gas turbines, including ultra-micro gas ones, which are among the most popular micro generators of electric power at the time. To minimize the risk of failure in the experiment and cost, simulation is used. To simulate the performance of gas turbines, the thermodynamic analysis tool called Cycle-Tempo is used. In this study, Cycle-Tempo was used for the zero-dimensional thermodynamic simulation of an ultra-micro gas turbine operated using producer gas as fuel. Our research contributions are the simulation of an ultra-micro gas turbine at a lower power output of about 1 kWe and the use of producer gas from leaf waste gasification as fuel in a gas turbine. The aim of the simulation is to determine the influence of air-fuel ratio on compressor power, turbine power, generator power, thermal efficiency, turbine inlet temperature and turbine outlet temperature. The simulation was carried out on condition that the fuel flow rate of 0.005 kg/s is constant, the maximum air flow rate is 0.02705 kg/s, and the air-fuel ratio is in the range of 1.55 to 5.41. The leaf waste gasification was simulated before, by using an equilibrium constant to get the composition of producer gas. The producer gas that was used as fuel had the following molar fractions: about 22.62% of CO, 18.98% of H2, 3.28% of CH4, 10.67% of CO2 and 44.4% of N2. The simulation results show that an increase in air-fuel ratio resulted in turbine power increase from 1.23 kW to 1.94 kW. The generator power, thermal efficiency, turbine inlet temperature and turbine outlet temperature decreased respectively from 0.89 kWe to 0.77 kWe; 3.17% to 2.76%; 782 °C to 379 °C and 705°C to 304 °C. The maximums of the generator power and thermal efficiency of 0.89 kWe and 3.17%, respectively, were obtained at the 1.55 air-fuel ratio. The generator power and thermal efficiency are 0.8 kWe and 2.88%, respectively, with the 4.64 air-fuel ratio or 200% excess air. The result of the simulation matches that of the experiment described in the literature.

Author(s):  
Takayuki Matsunuma ◽  
Hiro Yoshida ◽  
Norihiko Iki ◽  
Takumi Ebara ◽  
Satoshi Sodeoka ◽  
...  

A series of operation tests of a ceramic micro gas turbine has been successfully carried out. The baseline machine is a small single-shaft turbojet engine (J-850, Sophia Precision Corp.) with a centrifugal compressor, an annular type combustor, and a radial turbine. As a first step, an Inconel 713C alloy turbine rotor of 55 mm in diameter was replaced with a ceramic rotor (SN-235, Kyocera Corporation). A running test was conducted at rotational speeds of up to 140,000 rpm in atmospheric air. At this rotor speed, the compression pressure ratio and the thrust were 3 and 100 N, respectively. The total energy level (enthalpy and kinetic energy) of the exhaust gas jet was 240 kW. If, for example, it is assumed that 10% of the total power of the exhaust jet gas was converted into electricity, the present system would correspond to a generator with 24 kW output power. The measured turbine outlet temperature was 950°C (1,740°F) and the turbine inlet temperature was estimated to be 1,280°C (2,340°F). Although the ceramic rotor showed no evidence of degradation, the Inconel nozzle immediately in front of the turbine rotor partially melted in this rotor condition. As a second step, the Inconel turbine nozzle and casing were replaced with ceramic parts (SN-01, Ohtsuka Ceramics Inc.). The ceramic nozzle and case were supported by metal parts. Through tests with the ceramic nozzle, it became evident that one of the key technologies for the development of ceramic gas turbines is the design of the interface between the ceramic components and the metallic components, because the difference between the coefficients of linear thermal expansion of the ceramic and metal produces large thermal stress at their interface in the high-temperature condition. A buffer material made of alumina fiber was therefore introduced at the interface between the ceramic and metal.


Author(s):  
Norihiko Iki ◽  
Takahiro Inoue ◽  
Takayuki Matsunuma ◽  
Hiro Yoshida ◽  
Satoshi Sodeoka ◽  
...  

In order to develop a micro gas turbine with high turbine inlet temperature and thermal efficiency, a series of running tests has been carried out. J-850 jet engine (Sophia Precision Co., Ltd.) was chosen as a baseline machine. The turbine nozzle and the rotor are replaced by type SN-01 (Otsuka Ceramics Co., Ltd.) and type SN-235 (Kyocera Corporation) ceramic elements, respectively. By using type 3a engine, we succeeded one-hour running test of the engine without cooling and severe damages. The turbine inlet temperature was higher than 1000 °C. The rotating speed was about 120,000 rpm. Performances of the type 3a engine (with ceramic nozzle and rotor) and the type 1 (with Inconel alloy nozzle and ceramic rotor) were compared as follows: At the same rotation speed, turbine inlet temperature of the type 3a became higher than that of the type 1. Simultaneously, fuel consumption of type 3a was larger than that of the type 1. Thrust of the type 3a was slightly larger than that of the type 1. Those results imply that the thermal efficiency of type 3a is slightly, 2%, lower than that of the type 1. The present sealing configurations between ceramic nozzle-vanes and their holder plate and ceramic rotor-housing and metal combustion chamber were found to work well.


Author(s):  
Norihiko Iki ◽  
Hirohide Furutani ◽  
Sanyo Takahashi

The mirror gas turbine proposed by Tsujikawa and Fujii extends the applications of turbo machinery. The characteristic component of a mirror gas turbine is a thermal generator, which is a kind of “inverted Brayton cycle”. The operating sequence of the thermal generator is reverse that of an ordinary gas turbine, namely, the hot working fluid is first expanded, and then cooled, compressed, and finally exhausted. In this work, we investigated the theoretical feasibility of inserting a thermal generator to a small reheat gas turbine of 30–100kW classes. Using process simulator software, we calculated and compared the thermal efficiency of this reheat gas turbine to that of a micro gas turbine under several conditions, turbine inlet temperature. This comparison showed that the performances of the both gas turbines are significantly influenced by the performance of the heat exchanger used for the recuperator. The efficiency of the micro gas turbine is also improved by using water injection into the compressor to cool the inlet gas. The resulting thermal efficiency of this reheat gas turbine is about 7% higher than that of a micro gas turbine with the same power unit.


2005 ◽  
Vol 127 (2) ◽  
pp. 340-347 ◽  
Author(s):  
Alberto Traverso ◽  
Federico Calzolari ◽  
Aristide Massardo

Microturbines have a less complex mechanical design than large-size gas turbines that should make it possible to fit them with a more straightforward control system. However, these systems have very low shaft mechanical inertia and a fast response to external disturbances, such as load trip, that make this very difficult to do. Furthermore, the presence of the recuperator requires smooth variations to the Turbine Outlet Temperature (TOT), when possible, to ensure reduced thermal stresses to the metallic matrix. This paper, after a brief overview of microturbine control systems and typical transients, presents the expected transient behavior of two advanced cycles: the Externally Fired micro Gas Turbine (EFmGT) cycle, where the aim is to develop a proper control system set-up to manage safe part-load operations at constant rotational speed, and a solar Closed Brayton Cycle (CBC), whose control system has to ensure the maximum efficiency at constant rotational speed and constant Turbine Inlet Temperature (TIT).


Author(s):  
Nicola Aldi ◽  
Nicola Casari ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
...  

Over recent decades, the variability and high costs of the traditional gas turbine fuels (e.g. natural gas), have pushed operators to consider low-grade fuels for running heavy-duty frames. Synfuels, obtained from coal, petroleum or biomass gasification, could represent valid alternatives in this sense. Although these alternatives match the reduction of costs and, in the case of biomass sources, would potentially provide a CO2 emission benefit (reduction of the CO2 capture and sequestration costs), these low-grade fuels have a higher content of contaminants. Synfuels are filtered before the combustor stage, but the contaminants are not removed completely. This fact leads to a considerable amount of deposition on the nozzle vanes due to the high temperature value. In addition to this, the continuous demand for increasing gas turbine efficiency, determines a higher combustor outlet temperature. Current advanced gas turbine engines operate at a turbine inlet temperature of (1400–1500) °C which is high enough to melt a high proportion of the contaminants introduced by low-grade fuels. Particle deposition can increase surface roughness, modify the airfoil shape and clog the coolant passages. At the same time, land based power units experience compressor fouling, due to the air contaminants able to pass through the filtration barriers. Hot sections and compressor fouling work together to determine performance degradation. This paper proposes an analysis of the contaminant deposition on hot gas turbine sections based on machine nameplate data. Hot section and compressor fouling are estimated using a fouling susceptibility criterion. The combination of gas turbine net power, efficiency and turbine inlet temperature (TIT) with different types of synfuel contaminants highlights how each gas turbine is subjected to particle deposition. The simulation of particle deposition on one hundred (100) gas turbines ranging from 1.2 MW to 420 MW was conducted following the fouling susceptibility criterion. Using a simplified particle deposition calculation based on TIT and contaminant viscosity estimation, the analysis shows how the correlation between type of contaminant and gas turbine performance plays a key role. The results allow the choice of the best heavy-duty frame as a function of the fuel. Low-efficiency frames (characterized by lower values of TIT) show the best compromise in order to reduce the effects of particle deposition in the presence of high-temperature melting contaminants. A high-efficiency frame is suitable when the contaminants are characterized by a low-melting point thanks to their lower fuel consumption.


Author(s):  
Leonardo Pierobon ◽  
Ulrik Larsen ◽  
Tuong Van Nguyen ◽  
Fredrik Haglind

In off-shore oil and gas platform efficiency, the reliability and fuel flexibility are the major concerns when selecting the gas turbine to support the electrical and mechanical demand on the platform. In order to fulfill these requirements, turbine inlet temperature and pressure ratio are not increased up to the optimal values and one or more redundant gas turbines may be employed. With increasing incentives for reducing the CO2 emissions off-shore, improving the thermal efficiency has become a focus area. Due to the peculiar low turbine outlet temperature and due to space and weight constraints, a steam bottoming cycle is not a convenient solution. On the contrary, organic Rankine cycles (ORCs) present the benefits of high simplicity and compactness. Furthermore, the working fluid can be selected considering the temperature profile at which the heat is supplied; hence the heat transfer process and the thermal efficiency of the cycle can be maximized. This paper is aimed at finding the most optimal ORC tailored for off-shore applications using an optimization procedure based on the genetic algorithm. Numerous working fluids are screened through, considering mainly thermal efficiency, but also other characteristics of the fluids, e.g. stability, environmental and human health impacts, and safety issues. Both supercritical and subcritical ORCs are included in the analysis. The optimization procedure is first applied to a conservative ORC where the maximum pressure is limited to 20 bar. Subsequently the optimal working fluid is identified by removing the restriction on the maximum pressure. Different limits on hazards and global warming potential (GWP) are also set. The study is focused on the SGT-500 gas turbine installed on the Draugen platform in the Norwegian Sea. The simulations suggest that, when a high hazard is accepted, cyclohexane is the best solution. With a turbine inlet pressure limit of 20 bar, the combined gas turbine-ORC system presents an efficiency of 43.7%, corresponding to an improvement of 11.9%-points with respect to the gas turbine efficiency. With no upper pressure boundary, cyclohexane at 55.5 bar is the preferable working fluid with a combined thermal efficiency of 44.3%. The supercritical CO2 cycle with a maximum pressure of 192.9 bar is found to be the best alternative if an extremely low hazard is required.


Author(s):  
Alberto Traverso ◽  
Federico Calzolari ◽  
Aristide Massardo

Microturbines have a less complex mechanical design than large-size gas turbines that should make it possible to fit them with a more straightforward control system. However, these systems have very low shaft mechanical inertia and a fast response to external disturbances, such as load trip, that make this very difficult to do. Furthermore, the presence of the recuperator requires smooth variations to the Turbine Outlet Temperature (TOT), when possible, to ensure reduced thermal stresses to the metallic matrix. This paper, after a brief overview of microturbine control systems and typical transients, presents the expected transient behavior of two advanced cycles: the Externally Fired micro Gas Turbine (EFmGT) cycle, where the aim is to develop a proper control system set-up to manage safe part-load operations at constant rotational speed, and a solar Closed Brayton Cycle (CBC), whose control system has to ensure the maximum efficiency at constant rotational speed and constant Turbine Inlet Temperature (TIT).


Author(s):  
Keisuke Makino ◽  
Ken-Ichi Mizuno ◽  
Toru Shimamori

NGK Spark Plug Co., Ltd. has been developing various silicon nitride materials, and the technology for fabricating components for ceramic gas turbines (CGT) using theses materials. We are supplying silicon nitride material components for the project to develop 300 kW class CGT for co-generation in Japan. EC-152 was developed for components that require high strength at high temperature, such as turbine blades and turbine nozzles. In order to adapt the increasing of the turbine inlet temperature (TIT) up to 1,350 °C in accordance with the project goals, we developed two silicon nitride materials with further unproved properties: ST-1 and ST-2. ST-1 has a higher strength than EC-152 and is suitable for first stage turbine blades and power turbine blades. ST-2 has higher oxidation resistance than EC-152 and is suitable for power turbine nozzles. In this paper, we report on the properties of these materials, and present the results of evaluations of these materials when they are actually used for CGT components such as first stage turbine blades and power turbine nozzles.


Author(s):  
Katsuyoshi Tada ◽  
Kei Inoue ◽  
Tomo Kawakami ◽  
Keijiro Saitoh ◽  
Satoshi Tanimura

Gas-turbine combined-cycle (GTCC) power generation is clean and efficient, and its demand will increase in the future from economic and social perspectives. Raising turbine inlet temperature is an effective way to increase combined cycle efficiency and contributes to global environmental conservation by reducing CO2 emissions and preventing global warming. However, increasing turbine inlet temperature can lead to the increase of NOx emissions, depletion of the ozone layer and generation of photochemical smog. To deal with this issue, MHPS (MITSUBISHI HITACHI POWER SYSTEMS) and MHI (MITSUBISHI HEAVY INDUSTRIES) have developed Dry Low NOx (DLN) combustion techniques for high temperature gas turbines. In addition, fuel flexibility is one of the most important features for DLN combustors to meet the requirement of the gas turbine market. MHPS and MHI have demonstrated DLN combustor fuel flexibility with natural gas (NG) fuels that have a large Wobbe Index variation, a Hydrogen-NG mixture, and crude oils.


Author(s):  
Hideto Moritsuka

In order to estimate the possibility to improve thermal efficiency of power generation use gas turbine combined cycle power generation system, benefits of employing the advanced gas turbine technologies proposed here have been made clear based on the recently developed 1500C-class steam cooling gas turbine and 1300C-class reheat cycle gas turbine combined cycle power generation systems. In addition, methane reforming cooling method and NO reducing catalytic reheater are proposed. Based on these findings, the Maximized efficiency Optimized Reheat cycle Innovative Gas Turbine Combined cycle (MORITC) Power Generation System with the most effective combination of advanced technologies and the new devices have been proposed. In case of the proposed reheat cycle gas turbine with pressure ratio being 55, the high pressure turbine inlet temperature being 1700C, the low pressure turbine inlet temperature being 800C, combined with the ultra super critical pressure, double reheat type heat recovery Rankine cycle, the thermal efficiency of combined cycle are expected approximately 66.7% (LHV, generator end).


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