Portrait | Kyriacos Zygouakis

Kyriacos Zygourakis

Chemical and Biomolecular Engineering

Producing Biochars with Optimal Environmental Properties

Biochar amendments can increase soil fertility

Macropore structure of apple wood biochar (SEM image, 1500X)

Macropore structure of apple wood biochar (SEM image, 10000X)

Biochar amendments can increase the water-holding capacity of soils and improve nutrient retention

    Soil amendment with biochar produced by pyrolyzing biomass is a promising new approach with the potential to sequester large amounts of atmospheric carbon. At the same time, strong evidence suggests that amending soils with charcoal increases soil fertility, improves soil drainage, and helps manage nitrogen and phosphorus pollution.

    To better understand the fundamental mechanisms controlling biochar formation, our group is working to determine the pyrolysis conditions that lead to highly stable biochars with optimal carbon sequestration capacity, nutrient retention, and water-holding capacity. We have developed specialized reactors that allow us to accurately control the pyrolysis conditions and produce biochars from various feedstocks and for a wide range of heating rates, final heat treatment temperatures, and pyrolysis atmosphere. Several analytical techniques (NMR, XPS, gas adsorption, thermogravimetry with online mass spectroscopy, differential scanning calorimetry) are used to characterize the chemical composition, surface chemistry, pore structure, and reactivity of the produced biochars. Finally, we apply dynamic simulations and nonlinear least-squares methods to develop lumped kinetic models that will be used to design optimal reactors for biomass pyrolysis.

    The ultimate goal of our research is to develop“feedstock-blind” reactors for biomass pyrolysis. A thorough understanding of the mechanisms controlling biochar formation will allow us to fine-tune and control the operation of a reactor so that each biomass load will be processed with the optimal temperature program required to produce biochar with the desired environmental properties.

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