LIQUEFIED HYDROGEN FROM BROWN CARBON

LIQUEFIED HYDROGEN FROM BROWN CARBON

Subject : Science & tech

Context : A Japanese-Australian venture has begun producing hydrogen from brown coal in a A$500 million ($390 million) pilot project that aims to show liquefied hydrogen can be produced commercially and exported safely overseas.

Concept :

• Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.
• Liquefaction of hydrogen requires cooling to a temperature of -253 °C and subsequent storage in cryogenic containers. Liquefaction is an energy intensive process and can consume up to 35% of the energy in the stored hydrogen.
• The advantage of liquefied hydrogen is its high density compared to compressed gas, which means that more energy can be contained in a given volume. This is particularly beneficial for transportation of hydrogen.
• Generally, liquefaction of hydrogen is only appropriate where it is produced in large quantities and will be transported in bulk (or over long distances).

Brown Carbon

• This class of organic carbon, known for its light brownish color, absorbs strongly in the ultraviolet wavelengths and less significantly going into the visible.
• Types of brown carbon include tar materials from smoldering fires or coal combustion, breakdown products from biomass burning, a mixture of organic compounds emitted from soil, and volatile organic compounds given off by vegetation.
• Brown carbon contributes +0.25 W m-2 or about 19% of the total atmospheric absorption by anthropogenic aerosols, while 72% is attributed to black carbon and 9% is due to the coating effect of sulfate and organic aerosols on black carbon.