Scientists report new technique in production of green hydrogen and CO2 capture

Hydrogen is colorless and odorless, and using hydrogen to abate the climate change is only possible when the hydrogen is generated from renewable resources, termed as green hydrogen. Hydrogen has potential as a clean fuel, depending on how it's produced. Recently, scientists have achieved great progress in thermochemical conversion of woody biomass for production of green hydrogen and CO₂ capture.

The present hydrogen production is predominantly from fossil fuels such as natural gas, oil and coal, and it resulted in almost 900 million tonnes CO₂ emitted. As a clean energy carrier, hydrogen has attracted great interests world-wide to substitute fossil fuels and to reduce greenhouse gas emissions. But at present green hydrogen from renewable resources is less than 0.1% in the world hydrogen production, and this is largely from water electrolysis which is beneficial only when renewable electricity is used. Therefore, hydrogen production from diverse renewable resources is desirable.

Firewood can make fire, but how can firewood make hydrogen? A breakthrough in producing hydrogen from wood makes it possible. According to Shusheng Pang's review, a scientist from University of Canterbury, it presents recent advances in hydrogen production from woody biomass through thermochemical conversion processes. The first step in the process is advanced biomass steam gasification which produces a hydrogen-rich gas mixture consisting of H₂, CO, CO₂ and CH₄. Following the gasification, CO₂ in the gas is captured for reuse and the gas is further processed to convert CH₄ and CO to H₂ and CO₂ through reactions with steam. Eventually H₂ in the H₂/CO₂ mixture is separated for storage using organic liquid carrier through hydrogenation.

It is a new way to explore the opportunities for enhancing H₂ yield through steam inputs to biomass gasification and gas processing operations. Further research and development are required for implementation of the hydrogen production technologies from woody biomass. The next steps of the research will focus on technology proof at demonstration scale, the analysis of capital and operational costs, and verify the overall environmental benefits. The research on hydrogen is important to everyone, let us look forward to another breakthrough in this area.

More information:
Shusheng Pang, Recent advances in thermochemical conversion of woody biomass for production of green hydrogen and CO2 capture: A review, Journal of Bioresources and Bioproducts (2023). DOI: 10.1016/j.jobab.2023.06.002

Provided by Journal of Bioresources and Bioproducts