Aqueous Stream Characterization from Biomass Fast Pyrolysis and Catalytic Fast Pyrolysis

Abstract

Biomass pyrolysis offers a promising means to rapidly depolymerize lignocellulosic biomass for subsequent catalytic upgrading to renewable fuels. Substantial efforts are currently ongoing to optimize pyrolysis processes including various fast pyrolysis and catalytic fast pyrolysis schemes. In all cases, complex aqueous streams are generated containing solubilized organic compounds that are not converted to target fuels or chemicals and are often slated for wastewater treatment, in turn creating an economic burden on the biorefinery. Valorization of the species in these aqueous streams, however, offers significant potential for substantially improving the economics and sustainability of thermochemical biorefineries. To that end, here we provide a thorough characterization of the aqueous streams from four pilot-scale pyrolysis processes: namely, from fast pyrolysis, fast pyrolysis with downstream fractionation, in situ catalytic fast pyrolysis, and ex situ catalytic fast pyrolysis. These configurations and processes represent characteristic pyrolysis processes undergoing intense development currently. Using a comprehensive suite of aqueous-compatible analytical techniques, we quantitatively characterize between 12 g kg −1 of organic carbon of a highly aqueous catalytic fast pyrolysis stream and up to 315 g kg −1 of organic carbon present in the fast pyrolysis aqueous streams. In all cases, the analysis ranges between 75 and 100% of mass closure. The composition and stream properties closely match the nature of pyrolysis processes, with high contents of carbohydrate-derived compounds in the fast pyrolysis aqueous phase, high acid content in nearly all streams, and mostly recalcitrant phenolics in the heavily deoxygenated ex situ catalytic fast pyrolysis stream. Overall, this work provides a detailed compositional analysis of aqueous streams from leading thermochemical processesanalyses that are critical for subsequent development of selective valorization strategies for these waste streams.

Laboratory evolution reveals the metabolic and regulatory basis of ethylene glycol metabolism by Pseudomonas putida KT2440

“…Its oxidation products glycolaldehyde, glyoxal, glycolate, and in particular glyoxylate, also represent chemicals of industrial relevance, due to their use as reactive building blocks in the production of agro-, aroma-, and polymer chemicals, or pharmaceuticals (Sajtos, 1991;Mattioda, 2000;Yue et al, 2012). Glycolaldehyde is also a significant component of aqueous thermochemical wastewater streams and lignocellulosic hydrolysates, which renders those substrates highly toxic, and also a potentially attractive feedstock for microbes if toxicity tolerance improvements can be achieved (Czernik and Bridgwater, 2004;Kumar and Gupta, 2008;Yu et al, 2008;Lu et al, 2009;Vispute et al, 2010;Black et al, 2016;Jayakody et al, 2017Jayakody et al, , 2018. In nature, glycolate is a significant overflow metabolite of phytoplankton during autotrophic photorespiration, making up 10%-50% of excreted dry organic matter in marine environments (Lau and Armbrust, 2006).…”

Valorization of aqueous waste streams from thermochemical biorefineries

“…The aqueous waste stream used in this study contained 3.0 wt% organic carbon which is at the low end of the range of reported for organic carbon content, 3-14 wt%, depending on conversion conditions. 49,59 The aqueous phase was generated in a Davidson Circulating Riser (DCR) reactor, 59 in which the pyrolysis vapors from clean loblolly pine were upgraded using a HZSM-5 zeolite type catalyst (Johnson Matthey). Fig.…”

“…CFP of pine using a HZSM-5 type catalyst, that was provided from Johnson Matthey (London, UK), was performed with a coupled pyrolyzer/DCR system with detailed methods described elsewhere. 38,59,79 To generate the aqueous phase product used in the separation train, 1-2 mm pine particles were fed to the pyrolyzer with a biomass/N 2 ratio of 0.5, and the resulting pyrolysis vapors were fed to the DCR at 1.0 kg vapor per h. The DCR was operated under adiabatic conditions similar to industrial fluid catalytic cracking (FCC) units with feed rates set and maintained throughout the operation. Zeolite catalyst (1.8 kg) was charged into the regenerator and moved through the system by pressure differentials.…”

Limited life cycle and cost assessment for the bioconversion of lignin‐derived aromatics into adipic acid

“…The presence of catechol, phenol, o ‐, p ‐, and m ‐cresol, and guaiacol in the aqueous phase at elevated concentrations causes a double economic burden. In addition to the unexploited income, they represent waste that needs to be processed (Black et al, 2016).…”