Performance Characteristics of a 5kW Class Mid-Temperature Methane-Steam Reformer Under Different Operating Conditions

2018 ◽  
Vol 42 (4) ◽  
pp. 259-265 ◽  
Author(s):  
Kyungin Cho ◽  
Jinwon Yun ◽  
Sangseok Yu
Author(s):  
C Carcasci ◽  
B Facchini ◽  
S Harvey

A number of innovative gas turbine cycles have been proposed lately, including the humid air turbine (HAT) and the chemically recuperated gas turbine (CRGT). The potential of the CRGT cycle lies in the ability to generate power with a high efficiency and ultra-low NOx emissions. Much of the research work published on the CRGT cycle is restricted to an analysis of the thermodynamic potential of the cycle. However, little work has been devoted to discussion of some of the relevant design and operation issues of such cycles. In this paper, part-load performance characteristics are presented for a CRGT cycle based on an aeroderivative gas turbine engine adapted for chemical recuperation. The paper also includes discussion of some of the design issues for the methane-steam reformer component of the cycle. The results of this study show that large heat exchange surface areas and catalyst volumes are necessary to ensure sufficient methane conversion in the methane steam reformer section of the cycle. The paper also shows that a chemically recuperated aeroderivative gas turbine has similar part-load performance characteristics compared with the corresponding steam-injected gas turbine (STIG) cycle.


Author(s):  
Juan Yin ◽  
Yi-wu Weng

This paper investigated performance characteristics analysis of catalytic combustion by utilizing 1-D models incorporated heat and mass transfer correlations. The 1-D numerical results were compared with 2-D models studies and experimental data. The performance characteristics were mainly the effects of operating conditions on methane conversion rate. The comparable analysis confirmed that 1-D model can success in predicting performance of catalytic combustion when empiric inter-phase heat and mass transfer correlations are used and appropriate operating conditions are chosen.


Author(s):  
Nicola Zuliani ◽  
Rodolfo Taccani ◽  
Robert Radu

High temperature PEM (HTPEM) fuel cell based on polybenzimidazole polymer (PBI) and phosphoric acid, can be operated at temperature between 120°C and 180°C. Reactants humidification is not required and CO content up to 1% in fuel can be tolerated, affecting only marginally performance. This is what makes HTPEM fuel cells very attractive, as low quality reformed hydrogen can be used and water management problems are avoided. This paper aims to present the preliminary experimental results obtained on a HTPEM fuel cell fed with LPG using a compact steam reformer. The analysis focus on the reformer start up transient, on the influence of the steam to carbon ratio on reformate CO content and on the single fuel cell performance at different operating conditions. By analyzing the mass and energy balances of the fuel processor, fuel cell system, and balance-of-plant, a previously developed system simulation model has been used to provide critical assessment on the conversion efficiency for a 1 kWel system. The current study attempts to extend the previously published analyses of integrated HTPEM fuel cell systems.


Computation ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 54 ◽  
Author(s):  
Senthil Raman ◽  
Heuy Kim

A centrifugal compressor working with supercritical CO 2 (S-CO 2 ) has several advantages over other supercritical and conventional compressors. S-CO 2 is as dense as the liquid CO 2 and becomes difficult to compress. Thus, during the operation, the S-CO 2 centrifugal compressor requires lesser compression work than the gaseous CO 2 . The performance of S-CO 2 compressors is highly varying with tip clearance and vanes in the diffuser. To improve the performance of the S-CO 2 centrifugal compressor, knowledge about the influence of individual components on the performance characteristics is necessary. This present study considers an S-CO 2 compressor designed with traditional engineering design tools based on ideal gas behaviour and tested by SANDIA national laboratory. Three-dimensional, steady, viscous flow through the S-CO 2 compressor was analysed with computational fluid dynamics solver based on the finite volume method. Navier-Stokes equations are solved with K- ω (SST) turbulence model at operating conditions in the supercritical regime. Performance of the impeller, the main component of the centrifugal compressor is compared with the impeller with vaneless diffuser and vaned diffuser configurations. The flow characteristics of the shrouded impeller are also studied to analyse the tip-leakage effect.


2016 ◽  
Vol 68 (3) ◽  
pp. 349-360 ◽  
Author(s):  
Amit Singla ◽  
Amit Chauhan

Purpose The current trend of modern industry is to use machineries which rotate at high speed along with the capability of carrying heavy rotor loads. This paper aims at static thermal analysis of two different profiles of non-circular journal bearings – a true elliptical bearing and orthogonal bearing. Design/methodology/approach The Reynolds equation has been solved through finite difference method to compute the oil film pressure. Parabolic temperature profile approximation technique has been used to solve the energy equation and thus used for computation of various bearing performance characteristics such as thermo-hydrodynamic oil film pressure, temperature, load capacity, Sommerfeld number and power loss characteristics across the bearing. The effect of ellipticity ratio on the bearing performance characteristics has also been obtained for both the elliptical and vertical offset bearing using three different commercially available grades of oil (Hydrol 32, 68 and 100). Findings It has been observed that the thermo-hydrodynamic pressure and temperature rise of the oil film is less in orthogonal bearing as compared to the true elliptical bearing for same operating conditions. The effect of ellipticity ratio of non-circularity on bearing performance parameters have been observed to be less in case of elliptical bearing as compared to orthogonal bearing. It has been concluded that though the rise in oil film temperature is high for true elliptical bearing, but still it should be preferred over orthogonal profile under study, as it has comparably good load-carrying capacity. Originality/value The performance parametric analysis will help the designers to select such kind of non-circular journal bearing for various applications.


Author(s):  
Tae Won Song ◽  
Jeong L. Sohn ◽  
Tong Seop Kim ◽  
Sung Tack Ro

To investigate the possible applications of the SOFC/MGT hybrid system to large electric power generations, a study for the kW-class hybrid power system conducted in our group is extended to the MW-class hybrid system in this study. Because of the matured technology of the gas turbine and commercial availability in the market, it is reasonable to construct a hybrid system with the selection of a gas turbine as an off-the-shelf item. For this purpose, the performance analysis is conducted to find out the optimal power size of the hybrid system based on a commercially available gas turbine. The optimal power size has to be selected by considering specifications of a selected gas turbine which limit the performance of the hybrid system. Also, the cell temperature of the SOFC is another limiting parameter to be considered in the selection of the optimal power size. Because of different system configuration of the hybrid system, the control strategies for the part-load operation of the MW-class hybrid system are quite different from the kW-class case. Also, it is necessary to consider that the control of supplied air to the MW-class gas turbine is typically done by the variable inlet guide vane located in front of the compressor inlet, instead of the control of variable rotational speed of the kW-class micro gas turbine. Performance characteristics at part-load operating conditions with different kinds of control strategies of supplied fuel and air to the hybrid system are investigated in this study.


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