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Continuous fast and ex situcatalytic pyrolysis of blends of switchgrass with 15 wt % polyethylene (PE) was studied using a fluidized bed pyrolysis system. Higher than typical temperatures for biomass pyrolysis were utilized (630 °C) to overcome the higher thermal stability of polyethylene. For fast pyrolysis, the high pyrolysis temperature led to a lower yield of oil and a higher yield of gas from the switchgrass. When polyethylene was blended in, a small increase in the yield of oil was noted, and the oil had a slightly lower oxygen content and higher hydrogen content. GC/MS and NMR analysis showed that linear alkenes and alkanes were present in the oil in addition to phenolics, acids, and other oxygenates derived from biomass. However, a phase separated wax product was also formed, and this accounted for an estimated 27% of the input plastic carbon. Ethylene was also a major product of PE pyrolysis, accounting for 29% of the input plastic carbon. Only about 19% of the input plastic carbon was in the oil product. When ex situcatalytic pyrolysis was performed over HY at 250 °C, the oil product phase separated into a largely biomass derived fraction and a plastic derived fraction. When the catalysis was performed at 300 °C, there was a shift in reactivity for the blends compared with switchgrass only, decreasing CO formation and resulting in an oil rich in alkyl benzenes, alkyl naphthalenes, and alkyl phenols.

Viable thermochemical biorefineries require valuable outputs with optimized carbon distributions. While catalytic refining of biomass pyrolysis oils can produce fuel-grade hydrocarbons, more carbon-efficient pathways are needed to sustainably produce both renewable hydrocarbons─including those suitable for sustainable aviation fuel (SAF)─and carbonaceous solid materials. Bio-oils of sufficient quality and stability can undergo distillation, and catalytic hydrotreatment can upgrade the distillates without the interference of high-molecular-weight coke precursors. To further utilize the residues, we tested solvent liquefaction for upgrading of bio-oil distillate residues. Pyrolysis bio-oils from a lignocellulosic (switchgrass) and an oleaginous/proteinaceous (spirulina) biomass were distilled, and the distillate residues underwent liquefaction at 300 °C in microreactors with various solvents (water, ethanol, NaOH (aq), and formic acid (aq)). Optimal solvent conditions were downselected based on gas chromatography-mass spectrometry (GC-MS) of the products. Larger-scale reactions in optimal solvents (100 mL Parr reactor, 300 °C, 1500 psi) produced oils and hydrochar, the latter of which can be calcined into coke for manufacturing applications. For spirulina oil residues, ethanol-based liquefaction produced a 46% yield of oil; this represents more than double the yield for the NaOH-based liquefaction of switchgrass oil residues (20%). The oils contained straight-chain aliphatic compounds, which can potentially improve the processability for SAF applications.

•Thirty-one biochars were tested to inactivate E. coliO157:H7 (EHEC) in a model soil.•Slow pyrolysis paper biochar and walnut hull cyclone biochar were the most biocidal.•EHEC populations in unamended soil were 6.0–6.9 log CFU/g up to week 6.•≥2.5% paper or walnut hull biochar achieved ≥5.0 log CFU reduction of EHEC in soil.•pH values of soil with 2.5% paper or walnut hull biochars were 10.67 and 10.06.

The effect of calcium additives on the fast pyrolysis of switchgrass was studied by continuously pyrolyzing physical mixtures of the biomass with Ca(OH)2, CaO, and Ca(COOH)2in a laboratory scale fluidized bed reactor. Initial tests were performed by cofeeding 220 g/h of switchgrass with Ca(OH)2at ratios of 0.4/1 and 0.8/1 Ca(OH)2/biomass, running at reactor temperatures of 500, 550, and 600 °C, and using nitrogen or recycled pyrolysis gas as the carrier gas. In comparison with control experiments (Ca-free, biomass only), cofeeding Ca(OH)2led to a decrease in the yield of both organic phase bio-oil and organic compounds solubilized in the aqueous phase, while noncondensable gas yields were increased. The bio-oils exhibited a reduced oxygen content, a lower concentration of highly oxygenated compounds such as acetic acid and levoglucosan, and a small increase in the concentration of phenols and hydrocarbons. When higher Ca/biomass ratios or higher temperatures were tested, bio-oil yields were further reduced while the bio-oil deoxygenation rate was only slightly higher. The input calcium salts were converted to CaCO3because of a net trapping of CO2, promoting deoxygenation. Experiments with both N2and recycled pyrolysis gases as the carrier gas were performed to observe the effect of the changing atmosphere. The use of recycled pyrolysis gases led to increased bio-oil yields at temperatures of 500 and 550 °C, but a lower bio-oil yield at 600 °C for processing with Ca(OH)2. Organic phase bio-oil carbon yields were 10.4, 17.4, 15.2, and 22.8% from biomass for Ca(OH)2, CaO, Ca(COOH)2, and the Ca-free control experiment, respectively, with oxygen contents of 21, 20, 19, and 29.7 wt % at 550 °C (600 °C for Ca-free control). The conversion of the input calcium salt to CaCO3followed the pattern of Ca(OH)2> Ca(COOH)2> CaO, suggesting that bio-oil deoxygenation might not be only related to net CO2trapping as CaCO3, but also to the catalytic activity of Ca2+.

Soils in which fresh produce is grown can become contaminated with foodborne pathogens and are sometimes then abandoned or removed from production. The application of biochar has been proposed as a method of bioremediating such pathogen-contaminated soils. The objectives of the present study were to evaluate three fast-pyrolysis–generated biochars (FPBC; pyrolyzed in house at 450, 500, and 600°C in a newly designed pyrolysis reactor) and 10 United Kingdom Biochar Research Center (UKBRC) standard slow-pyrolysis biochars to determine their effects on the viability of four surrogate strains of Escherichia coliO157:H7 in soil. A previously validated biocidal FPBC that was aged for 2 years was also tested with E. colito determine changes in antibacterial efficacy over time. Although neither the UKBRC slow-pyrolysis biochars or the 450 and 500°C FPBC from the new reactor were antimicrobial, the 600°C biochar was biocidal (P< 0.05); E. colipopulations were significantly reduced at 3 and 3.5% biochar concentrations (reductions of 5.34 and 5.84 log CFU/g, respectively) compared with 0.0 to 2.0% biochar concentrations. The aged 500°C FPBC from the older reactor, which was previously validated as antimicrobial, lost efficacy after aging for 2 years. These results indicate that the biocidal activity of FPBC varies based on production temperature and/or age.

Catalytic fast pyrolysis (CFP) and tail-gas reactive pyrolysis (TGRP) of biomass produce partially deoxygenated bio-oils (10–20 wt % O) which allow for subsequent separation into phenolic and hydrocarbon fractions. The hydrocarbon fraction, while low in oxygen (<2 wt %), still requires further upgrading to become a finished fuel blendstock. In particular, the hydrogen deficiency, molecular weight distribution, and benzene content require further treatment. Specific biomass feedstocks like guayule carry over significant amounts of sulfur (∼500 ppm) even after catalytic hydrodeoxygenation. Our strategy was to fractionate the hydrocarbon fraction using distillation and then upgrade each fraction according to its needed product changes, including desulfurization. For each hydrocarbon fraction, sulfur levels ranged from 80–700 ppm, increasing with respect to decreasing volatility. Light fractions contained primarily one-ring aromatics, with heavy fractions increasing to two-ring aromatics. The lightest fraction (<143 °C) contained 6 wt % benzene, and fraction 2 (143–163 °C) required minimal treatment, as it consisted of nearly 100% BTEX (benzene, toluene, ethylbenzene, and xylenes). Sponge nickel catalysis in one step (<80 °C) eliminated sulfur in all fractions down to below 10 ppm with the exception of the hydrocarbon distillation residue, indicating that the sulfur remained labile even after biomass pyrolysis. Catalysis in two stages (80 °C, then 200 °C) eliminated benzene and produced naphtha and/or tetralin, which can be used to improve combustibility of jet fuels.

Production of stable, partially deoxygenated biomass pyrolysis bio-oils is needed to increase the fungibility of bio-oil for refining into fuels and chemicals. While zeolite catalyzed upgrading is commonly used to produce such liquids, the associated catalyst deactivation is a significant hurdle to overcome. Our group has previously reported the thermal deoxygenation of pyrolysis vapors that is carried out under an atmosphere partially consisting of recycled tail gas and without the use of externally added catalysts. In this study, thermal deoxygenation was further studied in a new and scaled-down (laboratory scale) pyrolysis system to allow for a systematic study and to better understand the factors affecting vapor deoxygenation. Temperature excursions from the fast pyrolysis temperatures near 500 °C and/or the catalyzing effect of accumulated biochar were hypothesized to be potential key parameters affecting vapor deoxygenation. Therefore, experiments were conducted by utilizing a recycled gas and inert atmosphere (N2) while varying process temperatures in the 500–750 °C range in both a fluidized bed pyrolysis reactor (in situ) and a static secondary chamber (ex situ) positioned downstream, after removal of bio-char from the vapor stream. Based on this arrangement, the oxygen content of bio-oils produced varied with temperature changes as follows: 31, 30, and 19 wt % for in situ temperatures of 500, 600, and 700 °C, and 31, 27, 23, and 19 wt % for ex situ temperatures of 500, 600, 700, and 750 °C, respectively. Compared with the use of nitrogen as carrier gas, utilization of the recycled gas atmosphere increased the yield of liquids and decreased production of gases. Organic bio-oil carbon yield was 18.5% from biomass under recycled gas at 700 °C and only with 12.8% under N2; however, the oxygen contents of the bio-oils were similar. Concentrations of BTEX were higher in bio-oils produced under the recycled gas atmosphere. Experiments were also conducted with biochars from switchgrass and rice hulls loaded in the ex situ chamber and maintained at 500 and 600 °C fixed beds. Bio-oils with oxygen contents as low as 19 wt % were produced with rice hull biochar at 600 °C. This suggests that biochar could have a catalytic deoxygenation effect particularly in a fixed or plugged bed, motivating further exploration of biochar as a catalyst for bio-oil deoxygenation.

Fast pyrolysis bio-oils from biomass can potentially integrate with petroleum refinery infrastructure for production of renewable fuels and chemicals. Besides hydrodeoxygenation, few feasible options exist for entry points. When considering advanced pyrolysis techniques such as catalytic and/or tail-gas reactive pyrolysis (TGRP), distillation for using both light and heavy ends becomes possible. Our goal was to demonstrate and optimize continuous production of liquid organic distillates and residual solids coke, both in appreciable yields for downstream conversion into renewable products. We fabricated a flash drum for continuous one-step distillations of four oils of varying oxygen content (ranging from 5 to 32 wt %). While a mesh demisting screen enhanced separation, removal of the screen ultimately improved overall yields. The flash drum proceeded to distill lower-oxygen oils (∼10 wt %) with 80 wt % time-on-stream yields over several hours; steady state was reached within 30–40 min. Bio-oils with moderate oxygen levels (20 wt %) took a noticeably longer time to attain steady state and gave 60 wt % yield. Under distillation conditions, oils from conventional pyrolysis (32 wt %) underwent condensation repolymerization due to reactive instabilities and produced only 6 wt % organic liquid yield. Solid coke residues were collected and converted into calcined coke, with Raman analysis indicating that catalytic and/or TGRP oil residues had higher molecular weight polyaromatics than those from traditional oil.

Catalytic fast pyrolysis of eucalyptus wood was performed on a continuous laboratory-scale fluidized bed fast pyrolysis system. Catalytic activity was monitored from use of fresh catalyst up to a cumulative biomass/catalyst ratio (B/C) of 4:1 over extruded pellets of three different ZSM-5 catalysts by tracking CO, CO2, H2, and C2H4production and bio-oil quality. The catalysts employed were extruded HZSM-5 with two different silica/alumina ratios (30 and 80) as well as one modified with Ga (SiO2/Al2O3= 30) by ion exchange, which was reduced under H2prior to pyrolysis. The deactivation of the catalysts over the course of the experiment was reflected in the decline in deoxygenation activity, following the order HZSM-5 (30) > HZSM-5 (80) > GaZSM-5 (30). HZSM-5 (30) lost most of its activity before a cumulative B/C of 2:1 was reached, while HZSM-5 (80) still showed significant deoxygenated activity at this exposure level. GaZSM-5 (30) still showed deoxygenation activity at B/C of >4:1. The improvement exhibited by HZSM-5 with an increasing SiO2/Al2O3ratio was attributed to reduced acid site density that decreased the propensity for coke formation as a result of reactions occurring between substrates at adjacent active acid sites. For reduced GaZSM-5, initial dehydrogenation activity aided in the production of aromatics by the olefin oligomerization and aromatization route up to B/C of ∼1.5:1, after which Ga became completely oxidized; however, the oxidized GaZSM-5 catalyst continued to exhibit improved decarbonylation and decarboxylation activities.

Metal‐modified HZSM‐5 catalysts were prepared by the ion exchange of NH4ZSM‐5 (SiO2/Al2O3=23) using Zn, Ga, Ni, and combinations thereof. The prepared catalysts were used to evaluate catalytic pyrolysis for the conversion of Eucalyptus urophyllato fuels and chemicals, specifically aromatic hydrocarbons, by using a micro‐scale pyrolysis reactor coupled with GC–MS. Two different biomass‐to‐catalyst ratios (1:5 and 1:10 w/w) were studied. The catalyst prepared with Ga by total ion exchange (Ga‐HZSM‐5 B, ≈7 wt % Ga) yielded the highest amount of aromatic hydrocarbons, whereas the catalysts modified with Ni produced the lowest yield of aromatic hydrocarbons. A correlation between the methane yield and benzene and p‐xylene selectivity was found for the catalysts, which was observed mainly for the Ni‐, Zn‐, and Ga‐Ni‐modified catalysts. The Ga‐modified catalysts were the most selective for xylenes, whereas the Ni‐based catalysts were the most selective for benzene production with a concurrent increase in methane production. The Zn‐modified catalysts were the most selective for toluene production. Eucalyptic aromatics: The conversion of eucalyptus wood to aromatic hydrocarbons by catalytic fast pyrolysis over several metal‐modified ZSM‐5 zeolites is studied by pyrolysis‐GC–MS. Ga modification of the zeolite leads to higher yields of aromatic hydrocarbons. The use of other metals can adjust the selectivity for individual compounds. These products can be used as renewable fuel additives or petrochemicals for use in a variety of current petroleum‐derived products.

Biomass feedstocks such as algae and cyanobacteria are highly sought after because of their high reproduction rates and growth densities, but their high concentrations of O and N heteroatoms are problematic for biofuel applications. Mild upgrading processes are necessary for producing fungible fuels from these renewable sources. We developed a process to upgrade spirulina-based bio-oil from tail-gas reactive pyrolysis (TGRP), using a combination of catalytic hydrotreatment and purification of the upgraded product. The TGRP bio-oil was distillated at high organic yields, and the distillates served as the feedstock for catalytic upgrading. Simultaneous hydrodeoxygenation and hydrodenitrogenation (HDO/HDN) was carried out in one step using a commercial ruthenium catalyst on carbon support. Using bio-oil distillates as feedstocks for hydrotreatment produced hydrocarbons at high space velocities. Reactor temperature was the critical variable, wherein the optimal temperature compromised between excessive yields loss and catalyst inactivity. While the HDO/HDN product contained relatively significant amounts of residual O and N (∼1 wt % each), the remaining O and N-containing compounds were removed via single aqueous-phase extraction with hydrochloric acid. The extraction step serves as a milder alternative to deep HDO/HDN processes that diminish final product yields.

Combustion characteristics of neat biomass fast-pyrolysis oil were studied in a horizontal combustion chamber with a rectangular cross-section. An air-assisted externally mixed nozzle known to successfully atomize heavy fuel oils was installed in a modified 100 kW (350 000 BTU/h nominal capacity) burner to explore full utility for pyrolysis oil (bio-oil) combustion in a furnace. Combustion experiments were conducted at air/fuel equivalence ratios of 0.46, 0.53, and 0.68 (116, 88, and 47% excess air, respectively) and compared to diesel fuel flames (control) at the two higher air/fuel equivalence ratios. In these experiments, the fuel flow rate was maintained at a constant energy input (equivalent of 24 kWth). The results revealed that, while the externally mixed nozzle could effectively atomize and ensure stable combustion of neat bio-oil at the set heat rate, this comes with a penalty associated with a lower peak flame temperature and, hence, heat flux. The formation of carbon monoxide (CO) decreases with an increasing air/fuel equivalence ratio for bio-oil combustion. The levels of carbon dioxide (CO2) and nitrogen oxides (NOx) increase with an increasing air/fuel equivalence ratio for bio-oil combustion and were slightly higher than that generated by diesel. Hydrocarbon emissions do not follow any defined trend with an increasing air/fuel equivalence ratio for bio-oil, as typically observed for diesel fuels as a result of the oxygenated nature of bio-oil.

Keine Anreicherung nötig: Eine empfindliche NMR‐Spektroskopiemethode wurde entwickelt, die gut aufgelöste 2D‐Spektren (15N‐1H und 13C‐1H) von großen Molekülen (wie Biopharmazeutika) liefert, ohne dass eine Isotopenanreicherung erforderlich ist. Diese Methode gab Einblicke in die Strukturen zweier lyophilisierter Aprotininproben sowie dreier Insulinproben in lyophilisierter, mikrokristalliner Suspension (rot; siehe Bild) und Fibrillenformen (grün).

The natural way: A sensitive NMR spectroscopic method is developed to obtain well‐resolved two‐dimensional spectra (15N–1H and 13C–1H) for natural‐abundance (that is, without the need for isotopic enrichment) large‐molecule samples, such as biopharmaceuticals. This method gives structural insights on two lyophilized aprotinin samples and three insulin samples in lyophilized, microcrystalline suspension formulation (red; see picture) and fibril (green) forms.

Because biomass fast-pyrolysis oils are a complex mixture comprising hundreds of compounds with a wide range of molecular weights, separating these components is challenging. However, because the composition of the mixture generally renders it reactive and unstable, the separation of bio-oil into more stable fractions remains desirable. This work used a packed column to perform fractional condensation of switchgrass fast-pyrolysis vapors generated in a laboratory-scale fluidized bed system operated at 560 g/h. The bio-oil was collected in nine fractions: the column separation system comprised six separation stages and a flask for the collection of bottoms, and the material escaping the column was collected by an electrostatic precipitator and cold trap. The obtained fractions were analyzed via GC–MS and NMR, and a mass balance was performed. Results were compared with a standard three-stage condensing system and batch distillation of the whole oil. The stability of the bio-oil fractions was compared via the formation of solid residue from bio-oil components from the online separation method, fractional distillation of standard bio-oil, and the evaporation of obtained fractions. A direct correlation between the concentration of compounds that are consumed during batch distillation and the amount of residue formed from each fraction was observed.

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