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So, i am trying to figure out the Thermodynamics of H2 adsorption onto a metal hydride. I need a bit of assistance if anyone knows these equations.
First off, since my MH alloy is the negative electrode in an electrolysis cell i use this equation DeltaT<(1/4D)-(Xad/x)^2 to figure out the percentage of protons on the electrode. To do any further equations i need to figure out the density of H2 ions on the surface of the Metal Hydride per 300ns.
The equations i need to do are:
MHydride reaction: M+x/2H2 <--> MHx+Q
Q=Temperature in Kilajoules/mole(g)
x= concentration of H2(moles/g)
A=Hydride forming substance
B=Non-hydride forming substance (lattice scaffold if you will)
n= atomic number of B atoms to every single A atom in the alloy alttice
Where since i am using an AB5 metal hydride the equation i need to use is ABn+(x/2)H2[@Pressure determined by the gibbs function]<---> AHx+nB+Q to figure out the overall concentration of Hydrogen into hydride state upon exposure of the 2 components (M+H2) to pressure. Different alloys require different pressures.
1/2µH2(p,T)=µH2(p,T,CH2)
p=pressure in bar
T=temperature in kelvin or kj.
C=Concentration of H2 (moles/gMH)
µH2= ideal gas
Once i know the thermodynamic characteristics of the particular alloy that i am working with, i can design a chamber ideal for producing the Metal Hydride reaction over many cycles. Once i know the relative H2 concentration on the cathode per pulse (each pulse being 300ns) i can figure out over, say 1 minute how much H2 migrated into the metal alloy electrode, as well as how much heat and pressure are needed to recover the H2, and to cause the MH reaction. Thus the feasibility of creating the device in-mind increases as i will know the exact parameters for the device to operate within (even under strictly ideal equations, the natural losses can be mitigated with a 5-10% scale, so increase pressure or temperature 5-10% what the equations say to make up for natural losses in the process. Whether ohmic, thermal, material etc.
So the alloy i am working with has a phase transition temperature of 70°C-170°C and a pressure adsorption requirement of 15-36bar, it is a LaNiCoAl alloy. The high temperature and pressure ratings of this material are not ideal for commercial Metal Hydride storage systems (in retrospect to other available alloys with lower requirements) however it is ideal for portable applications for high density H2 storage and release characteristics, as well as industrial due to it's high cycling ability (long cycle life). For my theoretical application, the alloy is ideal for the temperature of the hydride formation exceeds the average temperature for a well designed, low resistance DC electrolysis device. Which means, if tinkered properly, the excitement of electricity into water could directly cause the pressure requirements to move H2 into the metal alloy lattice. Thus direct generation, purification, pressurization, and solid state storage are achieved in one device. It sounds to good to be true, and often most things are. This is not. Strictly speaking, if the device is well designed, the ability for the device to supply a constant source of H2 to on-board MHydride storage tanks means that an electric vehicle powered by this device would never need to plug in to an electric socket. Electrochemical storage would power the "charging" of the device, while regenerative braking and imbedded PV panels would recharge the electrochemical cell when not in use. The electrochemical cells would only be used to recharge the device, the device itself would then only feed MH storage tanks when they were empty, meaning charging the device can happen while driving, and recharging the vehicle can happen during stops. Only water would need to be added every few weeks.
First off, since my MH alloy is the negative electrode in an electrolysis cell i use this equation DeltaT<(1/4D)-(Xad/x)^2 to figure out the percentage of protons on the electrode. To do any further equations i need to figure out the density of H2 ions on the surface of the Metal Hydride per 300ns.
The equations i need to do are:
MHydride reaction: M+x/2H2 <--> MHx+Q
Q=Temperature in Kilajoules/mole(g)
x= concentration of H2(moles/g)
A=Hydride forming substance
B=Non-hydride forming substance (lattice scaffold if you will)
n= atomic number of B atoms to every single A atom in the alloy alttice
Where since i am using an AB5 metal hydride the equation i need to use is ABn+(x/2)H2[@Pressure determined by the gibbs function]<---> AHx+nB+Q to figure out the overall concentration of Hydrogen into hydride state upon exposure of the 2 components (M+H2) to pressure. Different alloys require different pressures.
1/2µH2(p,T)=µH2(p,T,CH2)
p=pressure in bar
T=temperature in kelvin or kj.
C=Concentration of H2 (moles/gMH)
µH2= ideal gas
Once i know the thermodynamic characteristics of the particular alloy that i am working with, i can design a chamber ideal for producing the Metal Hydride reaction over many cycles. Once i know the relative H2 concentration on the cathode per pulse (each pulse being 300ns) i can figure out over, say 1 minute how much H2 migrated into the metal alloy electrode, as well as how much heat and pressure are needed to recover the H2, and to cause the MH reaction. Thus the feasibility of creating the device in-mind increases as i will know the exact parameters for the device to operate within (even under strictly ideal equations, the natural losses can be mitigated with a 5-10% scale, so increase pressure or temperature 5-10% what the equations say to make up for natural losses in the process. Whether ohmic, thermal, material etc.
So the alloy i am working with has a phase transition temperature of 70°C-170°C and a pressure adsorption requirement of 15-36bar, it is a LaNiCoAl alloy. The high temperature and pressure ratings of this material are not ideal for commercial Metal Hydride storage systems (in retrospect to other available alloys with lower requirements) however it is ideal for portable applications for high density H2 storage and release characteristics, as well as industrial due to it's high cycling ability (long cycle life). For my theoretical application, the alloy is ideal for the temperature of the hydride formation exceeds the average temperature for a well designed, low resistance DC electrolysis device. Which means, if tinkered properly, the excitement of electricity into water could directly cause the pressure requirements to move H2 into the metal alloy lattice. Thus direct generation, purification, pressurization, and solid state storage are achieved in one device. It sounds to good to be true, and often most things are. This is not. Strictly speaking, if the device is well designed, the ability for the device to supply a constant source of H2 to on-board MHydride storage tanks means that an electric vehicle powered by this device would never need to plug in to an electric socket. Electrochemical storage would power the "charging" of the device, while regenerative braking and imbedded PV panels would recharge the electrochemical cell when not in use. The electrochemical cells would only be used to recharge the device, the device itself would then only feed MH storage tanks when they were empty, meaning charging the device can happen while driving, and recharging the vehicle can happen during stops. Only water would need to be added every few weeks.