Report compares pyrolysis techniques

By Erin Voegele | August 08, 2011

The Energy Research Centre of the Netherlands recently published a thesis on  pyrolysis research written by ERC researcher Paul de Wild. According to de Wild, while many renewable resources, such as wind, solar, water and geothermal, can be used to produce renewable electricity, only biomass can be used to replace the petroleum used to produce chemicals. The paper, titled “Biomass Pyrolysis for Chemicals,” addresses pyrolysis techniques that use hard wood, soft wood and straw as feedstocks.

According to de Wild’s research, aquathermolysis, a hot pressurized water treatment, coupled with pyrolysis seems to be one promising technology option. The technology combination integrates fractionation of biomass with production of chemicals, notes de Wild in the paper. “Experiments with beech, poplar, spruce and straw indicate the potential of this hybrid concept to valorize lignocellulosic biomass,” states de Wild in the report’s summary.

The research also addresses staged degasification, a pyrolysis-based conversion method. “Because different thermal stabilities of the main biomass [constitutes] hemicelluloses, cellulose and lignin, different temperatures may be applied for a step-wise degradation into valuable chemicals,” said de Wild in the paper.

According to de Wild’s report, these two methods of thermochemical processing concepts focus on the carbohydrate fraction of biomass. The lignin is converted into low amounts of phenolics and char. While waste lignin coming out of biorefineries and pulp and paper mills has traditionally been burned for heat and power, de Wild suggests it would be beneficial to better exploit the value of lignin as a feedstock for fuels, chemicals and performance products.

“A pyrolysis based lignin biorefinery approach, called LIBRA, has been developed to transform lignin into phenolic bio-oil and bio char using state of the art bubbling fluidized bed reactor technology,” said de Wild in the report. “The bio-oil can potentially be applied as a precursor for value-added products such as a substitute for petrochemical phenol in various applications. The bio char can be used as a fuel, as a soil-improver or as a precursor for activated carbon.”

A full copy of the thesis can be found on the ERC website