Experimental Investigation of Fouling Remediation Strategies for Cross-Flow Microfiltration of Fast Pyrolysis Bio-Oil

Cross-flow microfiltration of fast pyrolysis bio-oil is a physical treatment pathway capable of reducing the filtered product's solids content to acceptable levels for fuel utilization and/or upgrading. However, the overall throughput of the process is hindered by the fouling that occurs on and/or within the filtration media over short operating periods. To improve the throughput from fast pyrolysis bio-oil cross-flow microfiltration, the use of offline and on-line cleaning techniques were experimentally evaluated. On-line cleaning strategies using permeate, solvent, and compressed air confirmed the reversibility of the accumulated fouling layer over a small (<10) number of cleaning cycles. The use of compressed air as a simple on-line cleaning strategy was further examined over extended operating times, including a total of 31 consecutive backflushing cycles. Compared to the reference case (no cleaning), on-line compressed air backflushing increased the overall throughput of low solids permeates by more than 100%. Ultimately, the demonstration of an on-line fouling remediation strategy for fast pyrolysis bio-oil cross-flow microfiltration increases the likelihood that it could be a viable treatment pathway for suspended solids and/or ash removal in pyrolysis liquids before end-use and/or upgrading of the biofuel.

Automated summary

Cross-flow microfiltration of fast pyrolysis bio-oil can be improved through the use of online cleaning strategies like compressed air backflushing, which has been shown to increase overall throughput of the process by more than 100%. The reversibility of fouling accumulation on the filtration media was confirmed, and the online cleaning techniques have shown promise in increasing the efficiency of the filtration process over extended operating times.