Feasibility Study on Dehydrogenation of LOHC Using Excess Exhaust Heat From a Hydrogen Fueled Micro Gas Turbine

2015 ◽  
Author(s):  
Balbina Hampel ◽  
Stefan Bauer ◽  
Norbert Heublein ◽  
Christoph Hirsch ◽  
Thomas Sattelmayer
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Energy Supply ◽  
Excess Energy ◽  
Exhaust Gas ◽  
Distributed Energy ◽  
Micro Gas Turbine ◽  
Exhaust Heat

In recent years, renewable energy technologies have received increasing attention. However, the constant availability of renewable energies is not predictable, so that technologies for excess energy storage become increasingly important. One possibility for the technical implementation of such a storage technology is to bind hydrogen, produced using this excess energy, to liquid organic compounds, so-called Liquid Organic Hydrogen Carriers (LOHC), where hydrogen is bound to a H2-lean LOHC molecule in an exothermal hydrogenation reaction. The dehydrogenation process releases the stored hydrogen in an endothermal reaction. This technology offers advantages such as storage and transport safety, along with the high energy density. LOHC systems can assist in the realization of future distributed energy supply networks, as well. Micro gas turbines (MGT) play an important role in distributed energy supply, so that the coupling of a hydrogen fueled MGT with a reactor for the dehydrogenation process is a desirable achievement. In such a combined system, the excess exhaust enthalpy can be used to maintain the endothermal dehydrogenation reaction without affecting the overall efficiency of the gas turbine. This paper investigates the feasibility of a direct coupling between a hydrogen fueled recuperated micro gas turbine and the dehydrogenation process using the excess exhaust heat. For this purpose, a numerical simulation based on energy balances and thermodynamic equilibrium is implemented to model the process. Primary criteria for the evaluation of the process feasibility are the MGTs exhaust gas temperature, the exhaust gas mass flow rate, and the LOHC mass flow rate through the dehydrogenation unit. These three parameters specify the mass flow rate of LOHC, which can be dehydrogenated and thus, the mass flow rate of released hydrogen. Using the implemented numerical model, the suitability of two different LOHCs, N-Ethylcarbazole and an industrial heat transfer oil is investigated at two different pressure levels with respect to thermodynamic feasibility and process efficiency. The results show that the usable excess enthalpy in the exhaust gas of the investigated Turbec T100 MGT is sufficient to release enough hydrogen for re-use as fuel in the micro turbine process for three of the four investigated cases.

Optimization of Supercritical CO2 Brayton Cycle for Simple Cycle Gas Turbines Exhaust Heat Recovery Using Genetic Algorithm

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Akshay Khadse ◽  
Lauren Blanchette ◽  
Jayanta Kapat ◽  
Subith Vasu ◽  
Jahed Hossain ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Supercritical Co2 ◽  
Heat Recovery ◽  
Brayton Cycle ◽  
Exhaust Gas ◽  
Exhaust Heat ◽  
Exhaust Heat Recovery

For the application of waste heat recovery (WHR), supercritical CO2 (S-CO2) Brayton power cycles offer significant suitable advantages such as compactness, low capital cost, and applicability to a broad range of heat source temperatures. The current study is focused on thermodynamic modeling and optimization of recuperated (RC) and recuperated recompression (RRC) configurations of S-CO2 Brayton cycles for exhaust heat recovery from a next generation heavy duty simple cycle gas turbine using genetic algorithm (GA). This nongradient based algorithm yields a simultaneous optimization of key S-CO2 Brayton cycle decision variables such as turbine inlet temperature, pinch point temperature difference, compressor pressure ratio, and mass flow rate of CO2. The main goal of the optimization is to maximize power out of the exhaust stream which makes it single objective optimization. The optimization is based on thermodynamic analysis with suitable practical assumptions which can be varied according to the need of user. The optimal cycle design points are presented for both RC and RRC configurations and comparison of net power output is established for WHR. For the chosen exhaust gas mass flow rate, RRC cycle yields more power output than RC cycle. The main conclusion drawn from the current study is that the choice of best cycle for WHR actually depends heavily on mass flow rate of the exhaust gas. Further, the economic analysis of the more power producing RRC cycle is performed and cost comparison between the optimized RRC cycle and steam Rankine bottoming cycle is presented.

Aerodynamic Optimization of the Radial Inflow Turbine for a 100kW-Class Micro Gas Turbine Based on Metamodel-Semi-Assisted Method

2013 ◽  
Author(s):  
Shuai Shao ◽  
Qinghua Deng ◽  
Zhenping Feng
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Total Pressure ◽  
Objective Functions ◽  
Aerodynamic Optimization ◽  
Micro Gas Turbine ◽  
Static Efficiency ◽  
Radial Inflow Turbine

In this paper, an aerodynamic optimization of the radial inflow turbine for a 100kW-class micro gas turbine is conducted based on the metamodel-semi-assisted idea. The idea is applied by first using the metamodel as a rapid exploration tool and then switching to the accurate optimization without metamodel for further exploration of the design space [1]. The non-dominated sorting genetic algorithm (NSGA-II) is used to drive the optimization process and the BP neural network is used to construct the metamodel. The optimization of this radial inflow turbine is divided into two parts, the stator optimization and the rotor optimization. The stator optimization is based on the accurate optimization strategy. The minimum total pressure loss of the stator and the maximum isentropic total-to-static efficiency of the stage are considered as the objective functions with constant mass flow rate as a constraint. The rotor optimization is conducted through the metamodel-semi-assisted idea. The maximum power output and isentropic total-to-static efficiency of the stage are considered as objective functions while keeping the mass flow rate to be constant. The accurate optimization system is demonstrated to be effective for the stator optimization, and the total pressure loss is reduced by 11.6% while the mass flow rate variation is less than 1%. The rotor optimization is conducted based on the metamodel-semi-assisted optimization and the results confirm the effectiveness of this new idea. The output power of the rotor increased by 1.5%, the isentropic total-to-static efficiency of the stage increased by 1.19% and the mass flow variation is less than 1%.

Design and Characterization of an Inlet Duct for Mass Flow Measurement in a Micro Gas Turbine Test Rig

2014 ◽  
Author(s):  
C. Buratto ◽  
A. Carandina ◽  
M. Morini ◽  
C. Pavan ◽  
M. Pinelli ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Loss ◽  
Resistive Load ◽  
Test Rig ◽  
Micro Gas Turbine ◽  
Inlet Duct

In this paper, a test rig for experimentation on a micro gas turbine is presented. The test rig consists of a micro gas turbine Solar T-62T-32, which, coupled with a 50 kVA alternator, can supply electrical energy to a calibrated resistive load bank. Particular attention is paid to the design of the inlet duct for the mass flow rate measurement. The basic issue was to create the intake duct for a micro gas turbine (MGT) test rig, in order to provide precise data about the mass flow rate and the thermodynamic air characteristics in the MGT inlet section. The inlet duct is also designed in order to allow future tests on inlet cooling technologies. The MGT is incorporated in a chassis for noise reduction, the dimensions of which are 540 mm (height), 570 mm (width) and 940 mm (length). These small dimensions lead to problems with the insertion of the duct. Moreover, the intake of the compressor is not axial but radial, and this means that a volute must be foreseen to convey the flux into the MGT. Several shapes of volute are analyzed in this paper, considering the effects on the pressure loss and the induction of turbulence. The challenge was to develop a fluid-dynamically efficient duct with the hindrance of a very small available space between the compressor casing, the gearbox and the fuel pipes inside the narrow noise-reduction chassis. The mass flow rate will be computed by means of the differential static pressure between the upstream and the downstream section of a Venturi tube. The choice of a Venturi was due to the fact that it produces a pressure loss lower than any other device, such as orifice plates or other nozzle shapes. Furthermore, the expected mass flow rate would lead to high fluid speeds and, as a consequence, the diameter ratio between the duct and the throat of the Venturi was chosen to be as high as possible.

Micro-Gas Turbine Feed With Natural Gas and Synthesis Gas: Variation of the Turbomachines’ Operative Conditions With and Without Steam Injection

2017 ◽  
Author(s):  
Massimiliano Renzi ◽  
Carlo Caligiuri ◽  
Mosè Rossi
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Steam Injection ◽  
Working Fluid ◽  
Fluid Composition ◽  
Micro Gas Turbine

In this work, the performances of a 100 kW Micro Gas Turbine (MGT) fed by Natural Gas (NG) and three different biomass-derived Synthesis Gases (SGs) have been assessed using a MATLAB® simulation algorithm. The set of equations in the algorithm includes the thermodynamic transformations of the working fluid in each component, the performance maps that describe the turbomachines’ isentropic efficiencies and pressure ratios as a function of the reduced mass flow rate and the reduced rotational speed, the performance and the pressure losses in each component, as well as the consumption of the other auxiliary devices. The electric power output, achieved using SGs, turns out to be lower or higher with respect to the one produced with the NG, depending on the fuel Lower Heating Value (LHV) but also largely on the variation of the working fluid composition. In this work, the effect of the steam injection on the MGT performance characteristics has been also investigated. Steam injection allows to obtain higher power and efficiencies using both NG and SGs at the rated rotational speed, mainly thanks to the increase of the turbine enthalpy drop and the reduction of the compressor consumption. Attention must be paid to the risk of the compressor stall, especially when using SGs, as the mass flow rate processed by the compressor decreases significantly. Moreover, another advantage of adopting the steam injection technique lies in the increased flexibility of the system: according to the users’ needs, the discharged heat can be exploited to generate steam, thus to enhance the electric performances, or to supply thermal power.

scholarly journals Off-Design Performances of an Organic Rankine Cycle for Waste Heat Recovery from Gas Turbines

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1105 ◽  
Author(s):  
Carlo Carcasci ◽  
Lapo Cheli ◽  
Pietro Lubello ◽  
Lorenzo Winchler
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Air Temperature ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Output ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Ambient Air ◽  
Air Mass

This paper presents an off-design analysis of a gas turbine Organic Rankine Cycle (ORC) combined cycle. Combustion turbine performances are significantly affected by fluctuations in ambient conditions, leading to relevant variations in the exhaust gases’ mass flow rate and temperature. The effects of the variation of ambient air temperature have been considered in the simulation of the topper cycle and of the condenser in the bottomer one. Analyses have been performed for different working fluids (toluene, benzene and cyclopentane) and control systems have been introduced on critical parameters, such as oil temperature and air mass flow rate at the condenser fan. Results have highlighted similar power outputs for cycles based on benzene and toluene, while differences as high as 34% have been found for cyclopentane. The power output trend with ambient temperature has been found to be influenced by slope discontinuities in gas turbine exhaust mass flow rate and temperature and by the upper limit imposed on the air mass flow rate at the condenser as well, suggesting the importance of a correct sizing of the component in the design phase. Overall, benzene-based cycle power output has been found to vary between 4518 kW and 3346 kW in the ambient air temperature range considered.

Evaluation of Axial Compressor Characteristics Under Overspray Condition

2013 ◽  
Author(s):  
Chihiro Myoren ◽  
Yasuo Takahashi ◽  
Manabu Yagi ◽  
Takanori Shibata ◽  
Tadaharu Kishibe
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Water Mass ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Test Facility ◽  
Compressor Performance ◽  
Water Mass Flow Rate

An axial compressor was developed for an industrial gas turbine equipped with a water atomization cooling (WAC) system, which is a kind of inlet fogging technique with overspray. The compressor performance was evaluated using a 40MW-class test facility for the advanced humid air turbine system. A prediction method to estimate the effect of WAC was developed for the design of the compressor. The method was based on a streamline curvature (SLC) method implementing a droplet evaporation model. Four test runs with WAC have been conducted since February 2012. The maximum water mass flow rate was 1.2% of the inlet mass flow rate at the 4th test run, while the design value was 2.0%. The results showed that the WAC decreased the inlet and outlet temperatures compared with the DRY (no fogging) case. These decreases changed the matching point of the gas turbine, and increased the mass flow rate and the pressure ratio by 1.8% and 1.1%, respectively. Since prediction results agreed with the results of the test run qualitatively, the compressor performance improvement by WAC was confirmed both experimentally and analytically. The test run with the design water mass flow rate is going to be conducted in the near future.

A New Concept of Impingement Cooling for Gas Turbine Hot Parts and Its Influence on Plant Performance

2003 ◽  
Author(s):  
B. Facchini ◽  
M. Surace ◽  
S. Zecchi
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Plants ◽  
Cooling System ◽  
Impinging Jets ◽  
Plant Performance ◽  
Transfer Coefficients ◽  
Impingement Cooling

Significant improvements in gas turbine cooling technology are becoming harder as progress goes over and over. Several impingement cooling solutions have been extensively studied in past literature. An accurate and extensive numerical 1D simulation on a new concept of sequential impingement was performed, showing good results. Instead of having a single impingement plate, we used several perforated plates, connecting the inlet of each one with the outlet of the previous one. Main advantages are: absence of the negative interaction between transverse flow and last rows impinging jets (reduced deflection); better distribution of pressure losses and heat transfer coefficients among the different plates, especially when pressure drops are significant and available coolant mass flow rate is low (lean premixed combustion chamber and LP turbine stages). Practical applications can have a positive influence on both cooled nozzles and combustion chambers, in terms of increased cooling efficiency and coolant mass flow rate reduction. Calculated effects are used to analyze main influences of such a cooling system on global performances of power plants.

scholarly journals Aerodynamic Loss Increase due to Individual Film Cooling Injections From Gas Turbine Nozzle Surface

1998 ◽  
Author(s):  
Ryo Kubo ◽  
Fumio Otomo ◽  
Yoshitaka Fukuyama ◽  
Yuhji Nakata
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Loss ◽  
Rate Ratio ◽  
Flow Rate Ratio ◽  
Design Stage ◽  
Pressure Side ◽  
Mass Flow Rate Ratio

A CFD investigation was conducted on the total pressure loss variation for a linear nozzle guide vane cascade of a gas turbine, due to the individual film injections from the leading edge shower head, the suction surface, the pressure surface and the trailing edge slot. The results were compared with those of low speed wind tunnel experiments. A 2-D Navier-Stokes procedure for a 2-D slot injection, which approximated a row of discrete film holes, was performed to clarify the applicable limitation in the pressure loss prediction during an aerodynamic design stage, instead of a costly 3-D procedure for the row of discrete holes. In mass flow rate ratios of injection to main flow from 0% to 1%, the losses computed by the 2-D procedure agreed well with the experimental losses except for the pressure side injection cases. However, as the mass flow rate ratio was increased to 2.5%, the agreement became insufficient. The same tendency was observed in additional 3-D computations more closely modeling the injection hole shapes. The summations of both experimental and computed loss increases due to individual row injections were compared with both experimental and computed loss increases due to all-row injection with the mass flow rate ratio ranging from 0% to 7%. Each summation agreed well with each all-row injection result. Agreement between experimental and calculated results was acceptable. Therefore, the loss due to all-row injections in the design stage can be obtained by the correlations of 2-D calculated losses from individual row injections. To improve more precisely the summation prediction for the losses due to the present all-row injections, extensive research on the prediction for the losses due to the pressure side injection should be carried out.

Influence of Steam Injection on Thermal Efficiency and Operating Temperature of GE-F5 Gas Turbines Applying VODOLEY System

2005 ◽  
Author(s):  
Mohsen Ghazikhani ◽  
Nima Manshoori ◽  
Davood Tafazoli
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Steam Injection ◽  
Gas Turbine Cycle

An industrial gas turbine has the characteristic that turbine output decreases on hot summer days when electricity demand peaks. For GE-F5 gas turbines of Mashad Power Plant when ambient temperature increases 1° C, compressor outlet temperature increases 1.13° C and turbine exhaust temperature increases 2.5° C. Also air mass flow rate decreases about 0.6 kg/sec when ambient temperature increases 1° C, so it is revealed that variations are more due to decreasing in the efficiency of compressor and less due to reduction in mass flow rate of air as ambient temperature increases in constant power output. The cycle efficiency of these GE-F5 gas turbines reduces 3 percent with increasing 50° C of ambient temperature, also the fuel consumption increases as ambient temperature increases for constant turbine work. These are also because of reducing in the compressor efficiency in high temperature ambient. Steam injection in gas turbines is a way to prevent a loss in performance of gas turbines caused by high ambient temperature and has been used for many years. VODOLEY system is a steam injection system, which is known as a self-sufficient one in steam production. The amount of water vapor in combustion products will become regenerated in a contact condenser and after passing through a heat recovery boiler is injected in the transition piece after combustion chamber. In this paper the influence of steam injection in Mashad Power Plant GE-F5 gas turbine parameters, applying VODOLEY system, is being observed. Results show that in this turbine, the turbine inlet temperature (T3) decreases in a range of 5 percent to 11 percent depending on ambient temperature, so the operating parameters in a gas turbine cycle equipped with VODOLEY system in 40° C of ambient temperature is the same as simple gas turbine cycle in 10° C of ambient temperature. Results show that the thermal efficiency increases up to 10 percent, but Back-Work ratio increases in a range of 15 percent to 30 percent. Also results show that although VODOLEY system has water treatment cost but by using this system the running cost will reduce up to 27 percent.

Redesigning the Auxiliary Power Unit Bleed Air Venturi

2012 ◽  
Author(s):  
Adam Dick ◽  
Peter Diamond
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Power Unit ◽  
Mass Flow ◽  
Flow Rate ◽  
Cold Weather ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Main Engine ◽  
Cooling Air

This paper examines the analysis of re-designing the Auxiliary Power Unit (APU) bleed air spool piece used on the Landing Craft, Air Cushion (LCAC). The APU supplies bleed air for main engine (ME) starting, anti-icing of the propeller shrouds during cold weather conditions and anti-icing of the filtration system that supplies both ME compartment cooling air and the APU gas turbine combustion air. An air-blast cockpit windshield cleaning system is also powered by APU bleed air. A spool piece is a venturi whose function is to limit a specific amount of airflow as it passes through a system. The current spool piece venturi dimensions allow an excess in APU bleed air to on-craft components, resulting in an exhaust gas temperature (EGT) over-temp in the gas turbine power producer. Such operating conditions occur during cold weather testing, when port and starboard propeller shroud anti-ice systems and APU combustion air/main engine compartment cooling air anti-ice systems are operating. In order to rectify this issue, a model analysis was created, determining the proper dimension of the spool piece venturi. Because spool piece venturies have been implemented fleet wide, it was a priority to reduce fabrication expenses of new materials. To best achieve this, the analysis will determine the size of a plain venturi that can be installed within the existing spool pieces. Referring to engine specifications, APU bleed air was limited to a certain flow rate. However, anti-ice components also required a specific mass flow rate in order to operate properly. It is within these boundaries that the proper diameter of the venturi was determined. This issue further expands upon the analysis of thermal testing, inlet and outlet pressures and the mass flow rate of the new venturi dimension.

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