(223f) Packed Column System for Adsorptive Denitrification of Biocrude

The transition from traditional nonrenewable hydrocarbon fuels towards biofuel alternatives brings with it a new set of environmental challenges. These more renewable fuel sources offer a strong performance replacement of their oil-based counterparts, but contaminants present due to the composition of the feedstock can create many environmental hazards with the formation of NOx products from combustion of nitrogen-containing compounds (NCCs) present in biosystems. It is clearly of increasing importance that removal of these NCCs is done either from biocrude before fraction separation or from the fuel fractions before use.

To this end, most efforts have gone towards controlling nitrogen content of the biomass source, and towards catalytic removal of NCCs from biocrude and blends. This approach is not cost-effective, and control of feed Nitrogen content is not an option for the majority of available biowaste. Adsorptive removal of NCCs provides a scalable, semi-continuous method of NCC removal from biocrude.

This work downselects to 3 sorbents and demonstrates their adsorption capacity for basic NCCs (represented by pyridine) and neutral NCCs (represented by indole). Sorbent characterization was done via TGA and SEM.

The presented work demonstrates development of a packed column system to adsorb NCCs from biocrude produced via hydrothermal liquefaction (HTL) of sewage sludge. Data presented demonstrate 99% removal of NCCs from a fuel fraction designated as sustainable aviation fuel (SAF) at an original NCC concentration of ~2000ppm to single digit ppm after treatment, as well as successful regeneration of the sorbent materials for continued use.

Successful proof-of-concept indicates an economically viable method for ensuring the minimization of NOx compound release. Adsorbent materials may be best suited to be used in a simulated moving bed system to develop a continuous method for NCC removal from biocrude and its derivatives.