scholarly journals A hydrogen generator coupled to a hydrogen heater for small scale portable applications

2022 ◽  
Vol 334 ◽  
pp. 06006
Author(s):  
Dirk Hufschmidt ◽  
Gisela M. Arzac ◽  
Maria Carmen Jiménez de Haro ◽  
Asunción Fernández
Keyword(s):  
Steady State ◽  
Catalytic Combustion ◽  
Hydrogen Generation ◽  
Pt Catalyst ◽  
Small Scale ◽  
Additional Energy ◽  
Solution Flow ◽  
Catalytic Combustor ◽  
H2 Flux ◽  
Hydrolysis Of

This study aims to build and test a small scale portable device able to couple a hydrogen generation system (based on a NaBH4 solution as liquid H2 carrier) to a hydrogen heater (based on the exothermic catalytic combustion of the released H2). The hydrogen generating system is based on the hydrolysis of stabilized solutions of NaBH4 (fuel solutions) which are pumped into the hydrolysis reactor. The generated H2 feeds the catalytic combustor. Two catalysts have been developed for the H2 generation and the combustion reactions able to operate at room temperature without need of additional energy supply. For the NaBH4 hydrolysis a Co-B catalyst was supported on a perforated and surface treated stainless steel (SS316) home-made monolith. For the flameless H2 catalytic combustion a Pt catalyst was prepared on a commercial SiC foam. The device was automatized and tested for the on-demand production of heat at temperatures up to 100ºC. In steady state conditions the NaBH4 solution flow is controlling the H2 flux and therefore the heater temperature. Once the steady-state is reached the system responds in a few minutes to up and down temperature demands from 80 to 100 ºC. The catalysts have shown no deactivation during the tests carried out in several days.

A High-Temperature Catalytic Combustor With Starting Burner

2000 ◽  
Vol 123 (3) ◽  
pp. 543-549 ◽  
Author(s):  
Y. Yoshida ◽  
K. Oyakawa ◽  
Y. Aizawa ◽  
H. Kaya
Keyword(s):  
Steady State ◽  
Catalytic Combustion ◽  
Cold Start ◽  
Heating System ◽  
Operating Conditions ◽  
Combustion System ◽  
Cold Starting ◽  
Steady State Operation ◽  
Wide Range ◽  
Catalytic Combustor

A catalytic combustion system has high potential to achieve low NOx emission level. When this combustion system is applied to a gas turbine, the required combustor performance must be maintained over a wide range of operating conditions. These conditions range from cold starting to steady-state operation. Particularly during the initial stage of cold starting when the catalyst is not yet activated, the catalyst must be heated by some means. This study proposes a new concept of a catalytic combustor with a direct heating system using vaporizing tube for starting burner in order to downsize the combustor and reduce the warm-up time during cold starts. The effectiveness of this concept is experimentally verified. Furthermore, NOx, CO, and HC emissions during startup can be reduced to a low level so as to achieve ultra-low pollution of the catalytic combustion over a wide range of operating conditions from cold start to steady-state operation. This paper outlines the operation concept covering cold start, verification of the concept through the experiments with flame visualization in the combustor, spray characteristics, construction of the combustor, and combustion characteristics that show low pollution in various operating conditions of the catalytic combustor.

A High-Temperature Catalytic Combustor With Starting Burner

2000 ◽  
Author(s):  
Yusaku Yoshida ◽  
Kenshun Oyakawa ◽  
Yukio Aizawa ◽  
Hiroshi Kaya
Keyword(s):  
Steady State ◽  
Catalytic Combustion ◽  
Cold Start ◽  
Heating System ◽  
Operating Conditions ◽  
Combustion System ◽  
Cold Starting ◽  
Steady State Operation ◽  
Wide Range ◽  
Catalytic Combustor

A catalytic combustion system has high potential to achieve low NOx emission level. When this combustion system is applied to a gas turbine, the required combustor performance must be maintained over a wide range of operating conditions. These conditions range from cold starting to steady-state operation. Particularly during the initial stage of cold starting when the catalyst is not yet activated, the catalyst must be heated by some means. This study proposes a new concept of a catalytic combustor with a direct heating system using vaporizing tube for starting burner in order to downsize the combustor and reduce the warm-up time during cold starts. The effectiveness of this concept is experimentally verified. Furthermore, NOx, CO, and HC emissions during startup can be reduced to a low level so as to achieve ultra-low pollution of the catalytic combustion over a wide range of operating conditions from cold start to steady-state operation. This paper outlines the operation concept covering cold start, verification of the concept through the experiments with flame visualization in the combustor, spray characteristics, construction of the combustor, and combustion characteristics that show low pollution in various operating conditions of the catalytic combustor.

Quantification of small-scale heterogeneity in aquatic aminopeptidase activity

2020 ◽  
Vol 84 ◽  
pp. 127-140
Author(s):  
BM Gaas ◽  
JW Ammerman
Keyword(s):  
Chlorophyll Fluorescence ◽  
Leucine Aminopeptidase ◽  
Hudson River ◽  
Aminopeptidase Activity ◽  
Small Scale ◽  
Analysis Instrument ◽  
Sequential Samples ◽  
Degree Of Confidence ◽  
The Mean ◽  
Hydrolysis Of

Leucine aminopeptidase (LAP) is one of the enzymes involved in the hydrolysis of peptides, and is sometimes used to indicate potential nitrogen limitation in microbes. Small-scale variability has the potential to confound interpretation of underlying patterns in LAP activity in time or space. An automated flow-injection analysis instrument was used to address the small-scale variability of LAP activity within contiguous regions of the Hudson River plume (New Jersey, USA). LAP activity had a coefficient of variation (CV) of ca. 0.5 with occasional values above 1.0. The mean CVs for other biological parameters—chlorophyll fluorescence and nitrate concentration—were similar, and were much lower for salinity. LAP activity changed by an average of 35 nmol l-1 h-1 at different salinities, and variations in LAP activity were higher crossing region boundaries than within a region. Differences in LAP activity were ±100 nmol l-1 h-1 between sequential samples spaced <10 m apart. Variogram analysis indicated an inherent spatial variability of 52 nmol l-1 h-1 throughout the study area. Large changes in LAP activity were often associated with small changes in salinity and chlorophyll fluorescence, and were sensitive to the sampling frequency. This study concludes that LAP measurements in a sample could realistically be expected to range from zero to twice the average, and changes between areas or times should be at least 2-fold to have some degree of confidence that apparent patterns (or lack thereof) in activity are real.

ISOBAM-stabilized Ni2+ colloidal catalysts: high catalytic activities for hydrogen generation from hydrolysis of KBH4

2020 ◽  
Vol 31 (13) ◽  
pp. 134003 ◽  
Author(s):  
Yuantao Pei ◽  
Liqiong Wang ◽  
Liang Huang ◽  
Yuetong Hu ◽  
Quanli Jia ◽  
...  
Keyword(s):  
Hydrogen Generation ◽  
Catalytic Activities ◽  
Hydrolysis Of

Hydrogen Generation by Hydrolysis of the Ball Milled Al-C-KCl Composite Powder in Distilled Water

2012 ◽  
Vol 519 ◽  
pp. 87-91 ◽  
Author(s):  
Xia Ni Huang ◽  
Zhang Han Wu ◽  
Ke Cao ◽  
Wen Zeng ◽  
Chun Ju Lv ◽  
...  
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Fine Particle ◽  
Composite Powder ◽  
Hydrogen Generation ◽  
Aluminum Particle ◽  
Generation Rate ◽  
Composite Powders ◽  
Fine Particle Size ◽  
Hydrolysis Of

In the present investigation, the Al-C-KCl composite powders were prepared by a ball milling processing in an attempt to improve the hydrogen evolution capacity of aluminum in water. The results showed that the hydrogen generation reaction is affected by KCl amount, preparation processing, initial aluminum particle size and reaction temperature. Increasing KCl amount led to an increased hydrogen generation volume. The use of aluminum powder with a fine particle size could promote the aluminum hydrolysis reaction and get an increased hydrogen generation rate. The reaction temperature played an important role in hydrogen generation rate and the maximum hydrogen generation rate of 44.8 cm3 min-1g-1of Al was obtained at 75oC. The XRD results identified that the hydrolysis byproducts are bayerite (Al(OH)3) and boehmite (AlOOH).

NON-STEADY STATE STUDY ON THE BASE HYDROLYSIS OF MONOIODOPENTAAMMINERUTHENIUM(III) COMPLEX

1975 ◽  
Vol 4 (7) ◽  
pp. 631-634 ◽  
Author(s):  
Hiroyuki Sakamoto ◽  
Haruo Makino ◽  
Keijiro Hamada ◽  
Akira Ohyoshi
Keyword(s):  
Steady State ◽  
Base Hydrolysis ◽  
State Study ◽  
Hydrolysis Of
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