Simulation of Sulfur-Iodine Thermochemical Hydrogen Production Plant Coupled to High-Temperature Heat Source

2009 ◽  
Vol 167 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Nicholas R. Brown ◽  
Seungmin Oh ◽  
Shripad T. Revankar ◽  
Karen Vierow ◽  
Salvador Rodriguez ◽  
...  
Keyword(s):  
High Temperature ◽  
Hydrogen Production ◽  
Heat Source ◽  
Production Plant ◽  
Temperature Heat

scholarly journals System Analyses of High and Low-Temperature Interface Designs for a Nuclear-Driven High-Temperature Electrolysis Hydrogen Production Plant

2009 ◽  
Author(s):  
E. A. Harvego ◽  
J. E. O’Brien ◽  
M. G. McKellar
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Hydrogen Production ◽  
Heat Pump ◽  
Interface Design ◽  
Production Plant ◽  
Brayton Cycle ◽  
Power Cycle ◽  
Temperature Heat ◽  
Reference Design

As part of the Next Generation Nuclear Plant (NGNP) project, an evaluation of a low-temperature heat-pump interface design for a nuclear-driven high-temperature electrolysis (HTE) hydrogen production plant was performed using the UniSim process analysis software. The low-temperature interface design is intended to reduce the interface temperature between the reactor power conversion system and the hydrogen production plant by extracting process heat from the low temperature portion of the power cycle rather than from the high-temperature portion of the cycle as is done with the current Idaho National Laboratory (INL) reference design. The intent of this design change is to mitigate the potential for tritium migration from the reactor core to the hydrogen plant, and reduce the potential for high temperature creep in the interface structures. The UniSim model assumed a 600 MWt Very-High Temperature Reactor (VHTR) operating at a primary system pressure of 7.0 MPa and a reactor outlet temperature of 900°C. The low-temperature heat-pump loop is a water/steam loop that operates between 2.6 MPa and 5.0 MPa. The HTE hydrogen production loop operated at 5 MPa, with plant conditions optimized to maximize plant performance (i.e., 800°C electrolysis operating temperature, area specific resistance (ASR) = 0.4 ohm-cm2, and a current density of 0.25 amps/cm2). An air sweep gas system was used to remove oxygen from the anode side of the electrolyzer. Heat was also recovered from the hydrogen and oxygen product streams to maximize hydrogen production efficiencies. The results of the UniSim analysis showed that the low-temperature interface design was an effective heat-pump concept, transferring 31.5 MWt from the low-temperature leg of the gas turbine power cycle to the HTE process boiler, while consuming 16.0 MWe of compressor power. However, when this concept was compared with the current INL reference direct Brayton cycle design and with a modification of the reference design to simulate an indirect Brayton cycle (both with heat extracted from the high-temperature portion of the power cycle), the latter two concepts had higher overall hydrogen production rates and efficiencies compared to the low-temperature heat-pump concept, but at the expense of higher interface temperatures. Therefore, the ultimate decision on the viability of the low-temperature heat-pump concept involves a tradeoff between the benefits of a lower-temperature interface between the power conversion system and the hydrogen production plant, and the reduced hydrogen production efficiency of the low-temperature heat-pump concept compared to concepts using high-temperature process heat.

Design of a Compact Ceramic High-Temperature Heat Exchanger and Chemical Decomposer for Hydrogen Production

2012 ◽  
Vol 33 (10) ◽  
pp. 853-870 ◽  
Author(s):  
Valery Ponyavin ◽  
Yitung Chen ◽  
Taha Mohamed ◽  
Mohamed Trabia ◽  
Anthony E. Hechanova ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Hydrogen Production ◽  
Temperature Heat

scholarly journals High temperature heat source generation with quasi-continuous wave semiconductor lasers at power levels of 6 W for medical use

2014 ◽  
Vol 19 (10) ◽  
pp. 101502
Author(s):  
Takahiro Fujimoto ◽  
Yusuke Imai ◽  
Kazuyoku Tei ◽  
Shinobu Ito ◽  
Hideko Kanazawa ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Source ◽  
Semiconductor Lasers ◽  
Continuous Wave ◽  
Temperature Heat

Numerical modeling of compact high temperature heat exchanger and chemical decomposer for hydrogen production

2008 ◽  
Vol 44 (11) ◽  
pp. 1379-1389 ◽  
Author(s):  
Valery Ponyavin ◽  
Yitung Chen ◽  
Anthony E. Hechanova ◽  
Merrill Wilson
Keyword(s):  
Numerical Modeling ◽  
High Temperature ◽  
Heat Exchanger ◽  
Hydrogen Production ◽  
Temperature Heat

scholarly journals Analysis of a High Temperature Gas-Cooled Reactor Powered High Temperature Electrolysis Hydrogen Plant

2010 ◽  
Author(s):  
M. G. McKellar ◽  
E. A. Harvego ◽  
A. M. Gandrik
Keyword(s):  
High Temperature ◽  
Hydrogen Production ◽  
Economic Analysis ◽  
Electric Power ◽  
Production Rate ◽  
Production Plant ◽  
System Pressure ◽  
Reference Design ◽  
High Temperature Gas ◽  
High Temperature Electrolysis

An updated reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production has been developed. The HTE plant is powered by a high-temperature gas-cooled reactor (HTGR) whose configuration and operating conditions are based on the latest design parameters planned for the Next Generation Nuclear Plant (NGNP). The current HTGR reference design specifies a reactor power of 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 322°C and 750°C, respectively. The reactor heat is used to produce heat and electric power for the HTE plant. A Rankine steam cycle with a power conversion efficiency of 44.4% was used to provide the electric power. The electrolysis unit used to produce hydrogen includes 1.1 million cells with a per-cell active area of 225 cm2. The reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes a steam-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The overall system thermal-to-hydrogen production efficiency (based on the higher heating value of the produced hydrogen) is 42.8% at a hydrogen production rate of 1.85 kg/s (66 million SCFD) and an oxygen production rate of 14.6 kg/s (33 million SCFD). An economic analysis of this plant was performed with realistic financial and cost estimating The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost. A cost of $3.03/kg of hydrogen was calculated assuming an internal rate of return of 10% and a debt to equity ratio of 80%/20% for a reactor cost of $2000/kWt and $2.41/kg of hydrogen for a reactor cost of $1400/kWt.

A Novel High-Temperature Ejector-Topping Power Cycle

1994 ◽  
Vol 116 (1) ◽  
pp. 1-7 ◽  
Author(s):  
B. Z. Freedman ◽  
N. Lior
Keyword(s):  
High Temperature ◽  
Heat Source ◽  
Gas Turbines ◽  
Saturation Pressure ◽  
Temperature Cycle ◽  
Power Cycle ◽  
Primary Fluid ◽  
Temperature Heat ◽  
Lower Temperature ◽  
Secondary Fluid

A novel, patented topping power cycle is described that takes its energy from a very high-temperature heat source and in which the temperature of the heat sink is still high enough to operate another, conventional power cycle. The top temperature heat source is used to evaporate a low saturation pressure liquid, which serves as the driving fluid for compressing the secondary fluid in an ejector. Due to the inherently simple construction of ejectors, they are well suited for operation at temperatures higher than those that can be used with gas turbines. The gases exiting from the ejector transfer heat to the lower temperature cycle, and are separated by condensing the primary fluid. The secondary gas is then used to drive a turbine. For a system using sodium as the primary fluid and helium as the secondary fluid, and using a bottoming Rankine steam cycle, the overall thermal efficiency can be at least 11 percent better than that of conventional steam Rankine cycles.

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