High-temperature electrolysis of copper chloride using hybrid proton exchange membrane for hydrogen production
Comprehensive utilisation of green hydrogen energy is an excellent pathway to reduce greenhouse gas emissions and simultaneously eliminate the carbon footprint released into the atmosphere. Meanwhile, hydrogen production via CuCl thermochemical cycle is an attractive process due to moderate-/lowt...
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| Format: | Thesis |
| Language: | English |
| Published: |
2022
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/103839/1/FK%202022%2080%20IR.pdf |
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| Summary: | Comprehensive utilisation of green hydrogen energy is an excellent pathway to
reduce greenhouse gas emissions and simultaneously eliminate the carbon
footprint released into the atmosphere. Meanwhile, hydrogen production via
CuCl thermochemical cycle is an attractive process due to moderate-/lowtemperature
requirements and high efficiency. Therefore, there is a huge
potential for producing hydrogen from the copper chloride (CuCl)
thermochemical cycle by utilising the power plant's excess heat. Currently, the
CuCl hydrogen electrolytic process is part of the CuCl thermochemical cycle. It
produces hydrogen at low temperatures utilising the expensive Nafion and
Nafion-based membranes. A high-temperature CuCl hydrogen electrolytic
process using a hybrid membrane as the alternative membrane to Nafion for
hydrogen production was performed in this study.
A polybenzimidazole/zirconium phosphate (PBI/ZrP) hybrid membrane was
synthesized using the solution mixing method followed by phosphoric acid (PA)
doping. It was then validated for water uptake, tensile strength,
thermogravimetric analysis (TGA), copper (Cu) diffusion and ionic exchange
capacity (IEC). The PBI/ZrP hybrid membrane was developed after the
screening process of PBI and sulphated poly (ether ether ketone) (SPEEK)
membrane with the advantage of having high tensile strength (85.17 MPa), high
ionic exchange capacity (3.2 × 10−3 mol g−1), low copper diffusion (7.87 × 10−7
cm2 s−1), sufficient water uptake (40 – 50 wt.%), a four-fold increase in proton
conductivity compared to pristine PBI. The scanning electron microscope (SEM)
was executed to evaluate the surface morphology of the membrane while SEMEDX
detected the membrane’s composition. For the parametric study, the CuCl
hydrogen electrolytic system with PBI/ZrP (0.5 A cm−2, 115 °C) produced 3.27
cm3 cm−1 hydrogen (highest). At a higher CuCl flowrate, the PBI/ZrP showed a
significant increment of 66% (up to 3.27 cm3 min−1) when the applied current density was changed from 0.1 to 0.5 A cm−2. The CuCl hydrogen electrolytic
process at 0.05 M CuCl concentration produced 2.69 cm3 min−1 and 2.15 cm3
min−1 hydrogen for PBI/ZrP and Nafion 117, respectively. The operating
temperature (p = 0.026) and current density (p = 0.000) were found statistically
significant based on the p-value < 0.05. The CuCl hydrogen electrolytic process
parameters were optimised using a response surface method (RSM) with a
central composite design (CCD). The optimised parameter settings were
temperature at 116 °C, current density at 0.773 A cm−2 and CuCl concentration
at 0.075 M to get the optimum hydrogen yield of 0.7167 cm3 min−1. The actual
hydrogen yield from the optimized parameter settings was 0.7709 cm3 min−1 with
a discrepancy of 7.56% from the predicted value.
The high-temperature CuCl hydrogen electrolytic process using a PBI/ZrP hybrid
membrane for hydrogen has been performed and proven a good alternative to
Nafion. At the same time, able to yield maximum hydrogen output with optimum
operating parameters, thus minimizing the associated cost in the hydrogen production. |
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