Microwave pyrolysis of biomass within a liquid medium

Abstract

A new approach to pyrolysis is demonstrated that uses microwave heating combined with an external liquid media at atmospheric pressure. The liquid acts as the inerting medium instead of the traditional inert gas, and also acts as a heat-sink to maintain the external temperature at the normal boiling point of the liquid. The ability to regulate the external temperature using a liquid offers significant advantages over established pyrolysis technologies and is only possible due to the selective and volumetric heating that occurs with microwaves. The new concept overcomes many of the challenges encountered in traditional and gas-based microwave pyrolysis processes, producing a bio-oil that naturally partitions into a sugar-rich aqueous phase and a phenol-rich organic phase. Energy requirements are as low as 2 kJ/g for 50% volatilisation, comparable to microwave pyrolysis using inert gases. It is shown that the new concept works effectively with both microwave-transparent and microwave-absorbent solvents.The liquid media also acts to eliminate arcing and prevent carbonaceous residues from forming, phenomena which have so far proved challenging for the scale-up of microwave pyrolysis processes.

Identification of Bio-oil Compound Utilizing Yeasts Through Phenotypic Microarray Screening

“…Utilisation profile studies using larger scale fermentations with the shortlisted yeasts would help to facilitate a determination of the conversion of levoglucosan into acetic acid over time, however this was not feasible during this study due to the cost of obtaining sufficient quantities of levoglucosan. However, it has been suggested that the availability of levoglucosan will increase in the near future, particularly from the development of new and emerging green technologies regarding the processing of biomass, where levoglucosan is a main product [31,47]. Nonetheless, the results from this study are still significant since the four shortlisted yeast strains have for the first time been identified as candidates for levoglucosan utilization.…”

“…The aim of this work was to identify novel yeast strains that can utilise levoglucosan directly using a PM screening approach. Particularly with pyrolysis technologies that have adopted microwave heating to drive the pyrolysis process, higher yields of levoglucosan have been quantified in the generated bio-oil compared to conventionally heated pyrolysis [30,31]; highlighting the attractiveness of this technology to produce sufficient amounts of this anhydrosugar for subsequent downstream processing. Nonetheless, the process still produces pyrolysis bio-oil containing thermal degradation compounds, such as 5-HMF, furfural and phenol that are detrimental to the growth of yeast.…”

Solvent-free manufacture of methacrylate polymers from biomass pyrolysis products

“…The area percentage method was used for the quantification of the compounds present in the pyrolysis liquid. 5,26 Identification of individual compounds was performed using the NIST library. All peaks below 1% intensity or below 80% match probability were excluded from analysis.…”

“…utilisation of the volatiles stream as a source of platform furan chemicals and the upgraded pyrolysis liquid as a fermentation feedstock. Full consideration of co-product utilisation is beyond the scope of this work, however there is an exciting opportunity for future work to use different technologies such as microwave pyrolysis to change the starting chemistry of the pyrolysis liquid 5 and subsequently to understand how the pyrolysis polymer properties and the overall mass balance are affected. Future work will also consider catalysts that can tolerate water within the pyrolysis liquids, thereby removing the need to undertake the first distillation step and purification or control agent strategies to increase the molecular weight could improve rheological properties.…”

“…These characteristics currently make it difficult to employ as a 'drop in' replacement feedstock, with extensive separation and/or upgrading processes needed to obtain specific products, as well as the associated challenge of finding markets for the separation and reaction co-products. [5][6][7][8][9][10] An alternative approach is to utilise reactive functional groups within the mixture to yield a spectrum of products, rather than attempt to isolate specific compounds.…”