Sylvain Charles Roland Verdier

Integration of catalytic fast pyrolysis and hydroprocessing: a pathway to refinery intermediates and “drop-in” fuels from biomass

Single-stage hydrotreating (HDT) of loblolly pine biocrude produced from catalytic pyrolysis was conducted to gain insight to HDT performance in terms of product yields, liquid product quality, and hydrogen consumption. Tests were performed with a sulfided HDT catalyst at three different conditions. The longest continuous time onstream operation (365 h) was achieved at an average bed temperature of 290 °C, 138 bar pressure, H2/oil ratio of 3300 Nl l−1, and a liquid hourly space velocity (LHSV) of 0.25 h−1. The average carbon yield of the HDT liquids were 77%, 83%, and 89% for experiments 1, 2, and 3, respectively. Also, the biocrude carbon that ended up in the gas phase varied between 4.3% and 8.9%. The carbon in the aqueous phase fraction was negligible—less than 0.5% of the biocrude carbon. The average hydrogen consumed ranged from 0.04 g to 0.07 g per 1 g of dry biocrude. The highest carbon content measured for the HDT liquid products from all three experiments was 87.13 wt% and the lowest was 79.03 wt%. GC-MS analysis suggests that the HDT product with oxygen content less than 5 wt% contained mainly naphthenic hydrocarbons. On the other hand, HDT products with oxygen content greater than 5 wt% contained a higher concentration of simple phenols and aromatic hydrocarbons (mono- and poly-). Catalyst deactivation was evident in the quality of the HDT liquid collected over time; the density and viscosity increased, the H/C ratio and carbon contents decreased; also, the gasoline fraction decreased while the gas oil fraction increased. The results from this work suggest that HDT of biocrude produced by catalytic biomass pyrolysis can be successfully upgraded into hydrocarbon liquid fuels without a stabilization step.

Increasing Flexibility in Two-Dimensional Liquid Chromatography by Pulsed Elution of the First Dimension: A Proof of Concept

This work demonstrates the development of an online two-dimensional liquid chromatography (2D-LC) method where the first dimension column is eluted by a sequence of pulses of increasing eluotropic strength generated by the LC pumps (pulsed-elution 2D-LC). Between the pulses, the first dimension is kept in a no-elution state using low eluent strength. The eluate from the first dimension is actively modulated using trap columns and subsequently analyzed in the second dimension. We demonstrate that by tuning the length and eluotropic strength of the pulses, peaks with retention factors in water, kw, above 150 can be manipulated to elute in 3-4 pulses. The no-elution state can be kept for 1-10 min with only minor changes as to which and how many pulses the peaks elute in. Pulsed-elution 2D-LC combined with active modulation tackles three of the main challenges encountered in 2D-LC and specifically online comprehensive 2D-LC: undersampling, difficulties in refocusing, and lack of flexibility in the selection of column dimensions and flow rates because the two dimensions constrain each other. The pulsed-elution 2D-LC was applied for the analysis of a basic fraction of vacuum gas oil. Peak capacity was 4018 for a 540 min analysis and 4610 for a 1040 min analysis.