Hydrogen Generation Using the Modular Helium Reactor

2004 ◽  
Author(s):  
Matt Richards ◽  
Arkal Shenoy
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Chemical Reactions ◽  
Nuclear Reactor ◽  
High Efficiency ◽  
Hydrogen Generation ◽  
Hybrid Process ◽  
Thermochemical Process ◽  
Process Heat ◽  
Splitting Water

Process heat from a high-temperature nuclear reactor can be used to drive a set of chemical reactions, with the net result of splitting water into hydrogen and oxygen. For example, process heat at temperatures in the range 850°C to 950°C can drive the sulfur-iodine (SI) thermochemical process to produce hydrogen with high efficiency. Electricity can also be used to split water, using conventional, low-temperature electrolysis (LTE). An example of a hybrid process is high-temperature electrolysis (HTE), in which process heat is used to generate steam, which is then supplied to an electrolyzer to generate hydrogen. In this paper we investigate the coupling of the Modular Helium Reactor (MHR) to the SI process and HTE. These concepts are referred to as the H2-MHR. Optimization of the MHR core design to produce higher coolant outlet temperatures is also discussed.

scholarly journals Low-Temperature Processed TiOx Electron Transport Layer for Efficient Planar Perovskite Solar Cells

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1676
Author(s):  
Md. Shahiduzzaman ◽  
Daiki Kuwahara ◽  
Masahiro Nakano ◽  
Makoto Karakawa ◽  
Kohshin Takahashi ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Temperature ◽  
Electron Transport ◽  
Low Temperature ◽  
High Efficiency ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Photovoltaic Properties

The most frequently used n-type electron transport layer (ETL) in high-efficiency perovskite solar cells (PSCs) is based on titanium oxide (TiO2) films, involving a high-temperature sintering (>450 °C) process. In this work, a dense, uniform, and pinhole-free compact titanium dioxide (TiOx) film was prepared via a facile chemical bath deposition process at a low temperature (80 °C), and was applied as a high-quality ETL for efficient planar PSCs. We tested and compared as-deposited substrates sintered at low temperatures (< 150 °C) and high temperatures (> 450 °C), as well as their corresponding photovoltaic properties. PSCs with a high-temperature treated TiO2 compact layer (CL) exhibited power conversion efficiencies (PCEs) as high as 15.50%, which was close to those of PSCs with low-temperature treated TiOx (14.51%). This indicates that low-temperature treated TiOx can be a potential ETL candidate for planar PSCs. In summary, this work reports on the fabrication of low-temperature processed PSCs, and can be of interest for the design and fabrication of future low-cost and flexible solar modules.

scholarly journals Thermal analysis of heat and power plant with high temperature reactor and intermediate steam cycle

2015 ◽  
Vol 36 (1) ◽  
pp. 3-18
Author(s):  
Adam Fic ◽  
Jan Składzień ◽  
Michał Gabriel
Keyword(s):  
Thermal Analysis ◽  
High Temperature ◽  
Heat Exchanger ◽  
Power Plant ◽  
Heat Pump ◽  
Nuclear Reactor ◽  
Temperature Level ◽  
High Temperature Process ◽  
Process Heat ◽  
Steam Cycle

Abstract Thermal analysis of a heat and power plant with a high temperature gas cooled nuclear reactor is presented. The main aim of the considered system is to supply a technological process with the heat at suitably high temperature level. The considered unit is also used to produce electricity. The high temperature helium cooled nuclear reactor is the primary heat source in the system, which consists of: the reactor cooling cycle, the steam cycle and the gas heat pump cycle. Helium used as a carrier in the first cycle (classic Brayton cycle), which includes the reactor, delivers heat in a steam generator to produce superheated steam with required parameters of the intermediate cycle. The intermediate cycle is provided to transport energy from the reactor installation to the process installation requiring a high temperature heat. The distance between reactor and the process installation is assumed short and negligable, or alternatively equal to 1 km in the analysis. The system is also equipped with a high temperature argon heat pump to obtain the temperature level of a heat carrier required by a high temperature process. Thus, the steam of the intermediate cycle supplies a lower heat exchanger of the heat pump, a process heat exchanger at the medium temperature level and a classical steam turbine system (Rankine cycle). The main purpose of the research was to evaluate the effectiveness of the system considered and to assess whether such a three cycle cogeneration system is reasonable. Multivariant calculations have been carried out employing the developed mathematical model. The results have been presented in a form of the energy efficiency and exergy efficiency of the system as a function of the temperature drop in the high temperature process heat exchanger and the reactor pressure.

Simulation of a High-Temperature Modular Reactor (HTMR) for Power and Coal-to-Liquid Fuel-Cogeneration Plant

2014 ◽  
Author(s):  
Mubenga Carl Tshamala ◽  
Robert T. Dobson
Keyword(s):  
Power Generation ◽  
High Temperature ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Superheated Steam ◽  
Nuclear Reactor ◽  
Electrical Power ◽  
Cogeneration Plant ◽  
Process Heat ◽  
Pipe Heat

Traditionally nuclear reactor power plants have been optimized for electrical power generation only. In the light of the ever-rising cost of ever-dwindling fossil fuel resources as well the global polluting effects and consequences of their usage, the use of nuclear energy for process heating is becoming increasingly attractive. In this study the use of a so-called cogeneration plant in which a nuclear reactor energy source is simulated using basic equations for the simultaneous production of superheated steam for electrical power generation and process heat, is considered and analyzed. A novel heat pipe heat exchanger is used to generate superheated steam for the process heat which is, in this case, a coal-to-liquid process (CTL). Natural circulation of sodium, via a thermo-syphon, is used in the heat pipe heat exchanger to transfer heat from the hot stream to the cold. The superheated steam for power generation is generated in a separate once-through helical coil steam generator. A 750 °C, 7 MPa helium cooled high-temperature modular reactor (HTMR) has been considered to simultaneously provide steam at 540 °C, 13.5 MPa for the power unit and steam at 430 °C, 4 MPa for a CTL production plant. The simulation and dynamic control of such a cogeneration plant is considered. In particular, a theoretical model of the plant will be simulated with the aim of predicting the transient and dynamic behavior of the HTMR in order to provide guideline for the control of the plant under various operating conditions. It was found that the simulation model captured the behavior of the plant reasonably well and it is recommended that it could be used in the detailed design of plant control strategies. It was also found that using a 1500 MW-thermal HTMR the South African contribution to global pollution can be reduced by 1.58%.

Hydrogen generation from formic acid decomposition on a highly efficient iridium catalyst bearing a diaminoglyoxime ligand

2018 ◽  
Vol 20 (8) ◽  
pp. 1835-1840 ◽  
Author(s):  
Sheng-Mei Lu ◽  
Zhijun Wang ◽  
Jijie Wang ◽  
Jun Li ◽  
Can Li
Keyword(s):  
High Temperature ◽  
Formic Acid ◽  
Room Temperature ◽  
High Efficiency ◽  
Hydrogen Generation ◽  
Acid Decomposition ◽  
Highly Efficient ◽  
Iridium Catalyst ◽  
Formic Acid Decomposition ◽  
Aqueous Formic Acid

A new iridium catalyst bearing a dioxime derived ligand has been developed for aqueous formic acid (FA) dehydrogenation in the absence of any additives. These catalysts can work at high temperature or room temperature with high efficiency and stability.

Mastication of Rubber. I. Mechanism of Plasticizing by Cold Mastication

1953 ◽  
Vol 26 (2) ◽  
pp. 386-405 ◽  
Author(s):  
M. Pike ◽  
W. F. Watson
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Physical Properties ◽  
Surface Area ◽  
Chemical Reactions ◽  
General Scheme ◽  
Basic Function ◽  
Large Surface Area ◽  
Essential Difference ◽  
High Shearing

Abstract The process of cold mastication has been rationalized in terms of recognized chemical reactions, and its essential difference from the hot mastication process has been demonstrated. Many apparently unrelated phenomena occurring on cold mastication, as, for example, are collected in a recent survey, can be interpreted as specific manifestations of the general scheme now presented. A clearer understanding of the basic function of the masticator is relevant to the design of such machines, i.e., the provision of high shearing forces for low-temperature chain rupture and the exposure of large surface area for high-temperature autoxidative breakdown. No acceleration of cold plasticization by added compounds is normally obtainable under the shear conditions of the Banbury mixer, but may be encountered under more efficient shear and in oxygen-deficient conditions. Cold mastication is revealed as a versatile method for producing rubbers of a wide variety of physical properties, i.e., softer (linear degraded) rubbers, harder and soluble (branched or cross-linked) rubbers, and insoluble (cross-linked) rubbers.

Gas-Bearing Turbomachinery

1968 ◽  
Vol 90 (4) ◽  
pp. 665-678 ◽  
Author(s):  
B. Sternlicht
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
High Speed ◽  
High Efficiency ◽  
Design Procedures ◽  
The Past ◽  
Long Life ◽  
Temperature Radiation ◽  
Gas Bearing ◽  
Selection Of

The paper presents gas bearing turbomachinery developments for the past decade. With the aid of examples of eight different requirements, it answers the question: “Why Gas-Bearing Turbomachinery?” These examples cover: No Contamination, high efficiency, low temperature, high temperature, radiation damage, reliability and long life, high speed and long life, and simplification. The paper points out the parameters and design procedures that are important to gas bearing turbomachinery designers. A table which enables selection of gas bearings and one which compares rotor weights for motor and turbine drives are included. Several remaining problem areas are identified and an example of bearing distortion, resulting from friction, is given.

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