Accelerated aging of fast pyrolysis bio-oil: a new method based on carbonyl titration

Abstract

Fast pyrolysis bio-oils are known to age upon storage at room temperature, resulting in changes to both physical properties (increase in viscosity) and chemical composition (decrease in carbonyl content).

Accelerated Aging of Fast Pyrolysis Bio-Oil Using Carbonyl Titration: Laboratory Analytical Procedure (LAP)

“…Record the average of three measurements as the initial carbonyl content (Cinitial) prior to accelerated aging. 11.2 The aging index has been calculated for a broad range of fast pyrolysis bio-oils, see further details in reference [2]. Typical results are between 6-14%, and correlate to 1-3 months of storage at room temperature.…”

“…This type of information would be very useful in many different industrial processing strategies and will inform decision making around both the processability of the bio-oil at different storage times, as well as how to run the process itself. This accelerated aging protocol correlates to 1-3 months of storage at room temperature for typical fast pyrolysis bio-oils [2].…”

“…Bio-oils undergo reactions that result in physical and chemical changes over time [1]. These changes typically result in an increase in molecular weight, decrease in some functional groups such as carbonyls, and an increase in viscosity; additionally, the aging process often leads to phase separation [2,3,4]. Studies have shown [2] that accelerated aging of bio-oils using this method closely mimics room temperature aging for long periods of time (3+ years).…”

“…4.2 This method uses total carbonyl content (measured by carbonyl titration) to track biooil aging. While viscosity has often been commonly used to track bio-oil aging, it has recently been shown that carbonyl content is a better metric [2]. First off, carbonyl titration has lower variability than does the viscosity measurement.…”

“…5.2 Bio-oils are known to undergo aging processes both at room temperature as well as in cold storage [2]. Due to this, analyses on bio-oil samples should be performed as quickly as possible following production.…”