Alkaline Thermal Treatment is a process used to produce hydrogen from seaweed using NaOH and a Suitable catalyst to give hydrogen and solid carbonates. These solid carbonates can be used to regenerate hydrogen using calcium carbonate.

1. ALKALINE THERMAL TREATMENT OF SEAWEED FOR
HIGH PURITY HYDROGEN PRODUCTION WITH
CARBON CAPTURE AND STORAGE POTENTIAL
REON SYLVESTER D CUNHA
199326
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2. CONTENTS
1. Introduction
2. Previous studies on Hydrogen production
3. Preparation of samples
4. Reactor and Alkaline Thermal Treatment
5. Hydrogen production from seaweed
6. Gas formation behavior
7. Regeneration of NaOH via Metathesis reaction
8. Conclusion/Results
9. References
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3. Brown Seaweed
Powdered Seaweed
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4. Introduction
• Global CO₂ emissions from energy use
35.7GT/year
• Current thermo chemical methods to generate
hydrogen are inefficient.
Sea weed
• Less investigated bioenergy source.
• High carbon Sequestration rate
• Can be cultivated using brine
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5. Previous studies on Hydrogen production
• Steam Gasification (low efficiency)
• Supercritical Gasification (Water at 22.1Mpa
and 374◦C )
• Hydrogen production from biomass feed
stocks.
• Use of catalysts like Ni/ZrO₂, Fe/Zro₂, Red mud
etc.
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6. Preparation of biomass and catalyst
• Brown seaweed is grounded to 150µm and dried.
• NaOH and Ca(OH)₂ are obtained from Sigma-Aldrich.
• Catalyst preparation: Dissolve 2.8g of Ni(NO₃)₂ 6H₂O in
80mL of ethanol.
• Add 5g of ZrO₂ and the mixture is heated.
• The catalyst is dried overnight and calcined.
• Reduced under H₂ atmosphere
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7. Reactor system
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8. Alkaline Thermal Treatment (ATT)
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9. Overall ATT Reaction C₆H₈O₆+ 12NaOH 6Na₂CO₃ +10H₂
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10. Hydrogen production from seaweed
• Amount of hydrogen produced is measured in dry ash free
(daf) mass.
• m₁ = m₀(1-a)(1-b) where a and b are the moisture content
and ash content respectively, m₀ is the mass of biomass.
• 70mmol(daf)g/seaweed of hydrogen was produced, greater
than those studied by other methods.
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11. Comparison to previous gasification studies
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12. Carbon capture and storage potential
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13. ATT reaction pathways
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14. Regeneration of hydroxide via Metathesis reaction
• NaOH has high alkalinity and low melting
point.
• Very expensive
• Regeneration of NaOH is essential
• Na₂CO₃ + Ca(OH)₂ CaCO₃ + 2NaOH
• Obtained CaCO₃ is stable and can be stored
permanently.
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15. Regeneration of NaOH
•
• Ca(OH)₂
NaOH
Na₂CO₃
CaCO₃
Precipitate Industrial use or carbon storage
Industrial waste
NaOH BIOMASS ATT
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17. Conclusion
• Catalytic ATT reaction generated 69.69 mmol
H₂/g seaweed in situ carbon capture.
• Ni based catalysts helps to generate more
hydrogen.
• This technique has BECCS potential
• This method provides a novel pathway to
utilize currently untapped biomass resources.
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18. References
• Zhang,K., Kim,W & Park, A.A. Alkaline thermal treatment of seaweed for
high purity hydrogen production with carbon capture and storage
potential. Nat commun 11,3783 (2020).
• Ishida, M., Otsuka, K., Takenaka, S. & Yamanaka, I. One step production of
CO and CO₂ free hydrogen from biomass J. Chem. Technol. Biotechnol.
80,281-284 (2005)
• Stonor, M. R., Chen, J. G. & Park, A. –H. A. Bio-Energy with Carbon Capture
and Storage (BECCS) potential: production of high purity H₂ from cellulose
via Alkaline thermal treatment with gas phase reforming of hydrocarbons
over various metal catalysts Int. J. Hydrog. Energy 42 25903-25913 (2017)
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