A new perspective for bio-energy with CO₂ capture

Hydrogen, seen as the “ultimate energy” for the 21st century, boasts benefits such as being clean and renewable as well as storable and versatile. The International Energy Agency predicts that 115 million tons of hydrogen will be required in 2030 to make global carbon dioxide net emissions zero by 2050. This makes green hydrogen a promising avenue to a carbon-free society.

By making use of biomass for hydrogen production we can reduce carbon emissions created by fossil fuels, thus helping to address the worsening energy crisis. The novel alkaline thermal treatment (ATT) technology for hydrogen production involves pyrolysis at atmospheric pressure and low temperature. From the viewpoint of the complete biomass life cycle, ATT has significant potential for “negative carbon emissions” and could substitute some fossil fuels.

To address that, the team believes that to maximize hydrogen production efficiency from the ATT reaction, the alkali used should promote the conversion of biomass into small gasifiable intermediates and in-situ carbon storage.

Following the review, four major conclusions were drawn. In order to better understand the transformation of model substances through different alkalis and identify more suitable biomass, further study is needed. To establish a suitable catalyst system based on the intermediate products of the ATT reaction, an analysis must be conducted into the deactivation mechanism of the catalyst, the interaction between the active site and carrier, and the catalytic structure-activity relationship.

Additionally, when weighing the advantages and disadvantages of in-situ and ex-situ reactions, designing reasonable reactors and developing efficient inlet/outlet methods are key to overcoming problems such as coking, limited mass transfer and catalyst regeneration caused by solid-solid reactions. Finally, economic assessment and energy consumption analysis should be conducted.