The production of fast pyrolysis bio-oil (FPBO) from secondary biomass is a promising technique for the production of liquid biofuels. However, the resulting FPBO is often viscous and chemically unstable, requiring significant upgrading while also being difficult to work with. To overcome this issue, FPBO can be hydrotreated using slurry hydrotreatment, which has a long history as a processing technique for upgrading viscous and difficult-to-work-with vacuum residues, and as such presents a solution. In this processing technique, the hydrotreatment catalyst is usually generated as dispersed MoS2 nanoparticles to improve feedstock-catalyst contact, as well as avert the diffusion problems that arise when utilizing a traditional, porous packed bed with a viscous feedstock. However, for such nanoparticulate dispersed catalysts, the nanoparticle structure and morphology play an important role in dictating activity and product distribution. Although much work has been done on characterizing dispersed MoS2 catalysts in the context of vacuum residues, such data is still scarce in the context of upgrading bio-oils. In this publication, we present a detailed characterization of in situ-generated MoS2 nanoparticles for the catalytic hydrotreatment of FPBO in a technology readiness level 5 (TRL5) slurry hydroprocessing plant. The results indicate a significant effect of the bio-based feedstock on the nanoparticle morphology, providing a starting point for further investigations into optimization of catalytic activity in the context of slurry hydrotrotreatment of bio-based feedstocks

Sustainable structural composites can significantly lower vehicle-related emissions. To evaluate the recycling of different composite materials, laboratory-scale pyrolysis was conducted and assessed both technically and environmentally. Two demonstrators were studied: a truck side skirt made from natural flax and hemp fibres with polypropylene (PP), and a car front header composed of glass fibres and PP. Additional materials examined included thermoplastic composites containing polyamide 6 (PA6), bio-based polyamide 11 (PA11) and thermoset polyester. Results showed that material type strongly influenced the pyrolysis outcome, product composition and recycling potential. Glass fibres could be recovered and reused as reinforced fibres, while natural fibres could be recovered as biooil for potential use in biofuel production. Polymers were recovered as pyrolysis products that, depending on their composition, can be used in different applications, from recovering monomers from PA6 to producing hydrocarbons that may replace naphtha (from PP) or aromatics (from polyester) in the petrochemical industry. Life cycle assessment (LCA) findings revealed that the climate impact of composite recycling is primarily driven by the environmental burdens of the recycling process itself and by the ability of recovered materials and chemicals to substitute conventional fossil-based alternatives. Efficient recycling pathways are therefore essential to maximising environmental benefits

Replacement of fossil-based chemicals with their bio-based analogues is vital to reduce the fossil dependence and greenhouse gas emissions. Accordingly, production of bio-based epoxy resin is important for a sustainable development. The aim of this study was to introduce a potential technique for producing phenolic compounds from biomass followed by a synthesis of bio-based epoxy resin. Hence, atmospheric ex-situ catalytic hydropyrolysis of wood sawdust was performed using a Molybdenum on Aluminum oxide (Mo/Al2O3) catalyst in a continuous drop-tube pyrolyzer for a selective production of phenolic compounds. The phenolics were purified and concentrated by liquid–liquid extraction and used to synthesize bio-based epoxy resin. The results revealed that a mild catalytic hydrotreatment of the pyrolysis vapor using Mo/Al2O3 at 673 K improved the phenolics yield. The organic pyrolysis oil contained up to 41 wt% phenolics whereof 20 wt% were volatile. The properties of the synthesized bio-based diglycidyl ether of bisphenol A epoxy resin (pyroEP) was comparable to those of commercial epoxy resin. The glass transition temperature of 426 K and reaction energy of 324 kJ/kg confirmed the successful production of a high-performance, sustainable epoxy resin. 

Thermochemical recycling of medical plastic waste (MPW) was evaluated experimentally and through development of mass & energy balances. Fluidized bed (FB) steam cracking of MPW at a centralized petrochemical site was compared to thermal and catalytic pyrolysis of MPW to intermediate WAX (thermal) and POil (catalytic) feedstocks at a decentralized site, followed by FB steam cracking of WAX and POil at a centralized petrochemical site. Pyrolysis and FB steam cracking experiments were performed in lab-scale reactors. Steam cracking yields of primary products (light olefins, C2-3 alkynes, BTXs) were highest for MPW, followed by WAX, and POil feedstocks. Higher steam cracking temperature increased the primary product yields for the MPW feedstock but showed a less significant effect in WAX and POil cases. For all cases, higher cracking temperature increased chain scission and hydrogen abstraction, resulting in rising yields of ethylene, methane, and hydrogen, and lower yields of longer chain aliphatic hydrocarbons. Material, carbon, and energy balances, developed from experimental results, showed that excess heat from incineration of pyrolysis and steam cracking byproducts can meet the energy demands of the pyrolysis and steam cracking processes. The balances also showed that direct FB steam cracking of MPW can achieve high product yields and high rates of fossil carbon recycling. However, steam cracking of WAX feedstock, the product of pyrolysis pre-treatment, can achieve moderate product yields and fossil carbon recycling while realizing several practical advantages: easier transport, reduced need for feedstock preparation, and removal of ash and heteroatoms for improved steam cracker operability. 

Paper-based packaging is a complex multi-material composed of paper (fibers), plastics, and metals, making efficient material recycling complicated. Currently, most of the fibers are recycled into new paper products while the residual material is commonly incinerated. Therefore, to improve the circularity and reduce the fossil dependency chemical recycling is needed. In this study, recycling of the residual materials was evaluated by thermal and catalytic pyrolysis. First, screening tests were performed using five reject materials and four catalysts in an analytical scale and then, a selection of catalyst and reject materials were evaluated in lab-scale followed by a techno-economic assessment. Experimental results indicated that the conversion was more efficient if the reject had high content of plastics compared to fibers, leading to products with increased heating value, higher hydrocarbon yield and less reactive oxygenates compared to the rejects with low plastic ratio. In the thermal pyrolysis 54 % of the weight of the feedstock and 70 wt% of the carbon in the feedstock ended up in a solid organic product (wax) which contained hydrocarbons and alcohols. In the analytical catalytic pyrolysis, HZSM-5 gave the best result in terms of cracking, deoxygenation, and aromatization. Ex-situ catalytic pyrolysis using HZSM-5 resulted in an improved quality of organic liquid with reduced hydrocarbon length as well as deoxygenated and aromatic compounds. The yield of the organic liquid was up to 19 wt% and contained mainly monoaromatics. The techno-economic evaluation showed, for processing 100,000 tons year−1 residual material, the total plant investment and the annual profit are about 29 and 12 million Euros, respectively, if no incentive for treating the residual material.

This study aimed to investigate the critical elements of the biomass ex situ catalytic hydropyrolysis (CHP) concept to improve the quality of fast pyrolysis bio-oil (FPBO) for further coprocessing in a fluid catalytic cracking (FCC) refining unit. Generally, the high oxygen and low hydrogen contents of biomass result in a bio-oil with low quality, necessitating its upgrading, which can be performed as integrated in the pyrolysis process via in situ or ex situ configuration. In this work, the quality of stem wood-derived pyrolyzates (520 °C) was improved via ex situ CHP (400 °C) using a continuous bench-scale drop tube pyrolyzer (60 g h-1), and then the produced FPBO was coprocessed with vacuum gas oil (VGO) fossil oil using a lab-scale FCC unit (525 °C). CHP of stem wood was carried out using different metal-acid catalysts such as Ni/HZSM-5, Ni/HBeta, Mo/TiO2, and Pt/TiO2 at atmospheric pressure. FCC runs were performed using an equilibrium FCC catalyst and conventional fossil FCC feedstock cofed with 20 wt % stem wood-derived bio-oil in a fluidized bed reactor. Cofeeding the nonupgraded FPBO with fossil oil into the FCC unit decreased the generation of hydrocarbons in the range of gasoline and naphtha, indicating that bio-oil needs to be upgraded for further coprocessing in the FCC unit. Experimental results showed that different catalysts significantly affected the product composition and yield; Ni-based catalysts were strongly active tending to generate a high yield of gas, while Mo- and Pt-based catalysts seemed better for production of liquid with improved quality. The quality of FPBO was improved by reducing the formation of reactive oxygenates through the atmospheric CHP process. The composition of oil obtained from hydropyrolysis also showed that the yields of phenols and aromatic hydrocarbons were enhanced. © 2024 The Authors. 

Reducing the use of fossil fuels is an ongoing and important effort considering the environmental impact and depletion of fossil-based resources. The combination of ablative fast pyrolysis and hydroprocessing is explored as a pathway allowing bio-based intermediates (BioMates) integration in underlying petroleum refineries. The proposed technology is validated in industrially relevant scale, identifying pros and cons towards its commercialization. Straw from wheat, rye and barley was fed to ablative fast pyrolysis rendering Fast Pyrolysis Bio-Oil (FPBO) as the main product. The FPBO was stabilized via slurry hydroprocessing, rendering a stabilized FPBO (sFPBO) with 49 % reduced oxygen content, 71 % reduced carbonyl content and 49 % reduced Conradson carbon residue. Fixed bed catalytic hydroprocessing of sFPBO resulted in the production of BioMates, a high bio-content product to be co-fed in established refinery units. Compared to the starting biomass, BioMates has 83.6 wt% C content increase, 92.5 wt% O content decrease, 93.0 wt% water content decrease, while the overall technology has 20 wt% conversion yield (32 wt% carbon yield) from biomass to BioMates. © 2022 The Author(s)

There is an urgent need for the development of viable recycling solutions for the increasing waste streams of glass fiber composites (GFRPs) from all sectors i.e. leisure boats, windmills and building constructions. Two potential recycling methods that can separate and recover both the polymers and the high-quality fibers from these kinds of materials are pyrolysis and solvolysis. In this project recycling of an epoxy-based Endof-Life wind turbine blade was evaluated in lab scale using the two methods. In previous literature the main focus has been on the quality of the fibers but in this project the main focus was to compare the chemical composition of the oil products. The produced oils from solvolysis and pyrolysis have been compared with a multianalysis approach by using elemental analysis, GC-MS, pyro-GC-MS/FID, 2D NMR (HSQC) for gaining more information about the chemical structure of the produced monomers (phenols), oligomers and polymers. Almost all the volatile matter in the End-of-Life wind turbine blade was recovered as pyrolysis oil, 36 wt.% yield. The solvolysis oil yield was lower, 17 wt.%, mainly due to a major part of the solvolysis oil ended up in the aqueous solvent. The composition of the oils from both technologies was analyzed based on both their volatile i.e. monomeric and polymeric content. The result point to that both methods produced oils with similar polymeric parts according to NMR and pyro-GC-MS/FID, based on an oxygenated aliphatic network connected with aromatic phenolic structures. Increased information of chemical oil composition will be useful for further processing as raw material in refineries/chemical industries. The monomeric part of the oil produced from pyrolysis was found in relatively large amounts, ~57 wt.%, and can be a future high-value product from recycling of wind turbine blades. The total recovery of phenolics from the pyrolysis was 18 wt.% of the wind turbine blade weight.

Lignocellulosic biomass from energy crops, i.e., short rotation coppice willows such as Salix spp., can be used as feedstock for production of transportation biofuels. Biomass conversion via fast pyrolysis followed by co-refining with fossil oil in existing refinery infrastructure could enable a fast introduction of large-scale production of biofuels. In this study, Salix was first liquefied using ablative fast pyrolysis in a pilot scale unit. The resulting pyrolysis oil, rich in oxygenates, was thereafter co-refined in 20 wt% ratio with fossil feedstock using two separate technologies, a fluidized catalytic cracking (FCC) laboratory unit and a continuous slurry hydroprocessing pilot plant. In the FCC route, the pyrolysis oil was cracked at 798 K using a commercial FCC catalyst at atmospheric pressure, while in the hydroprocessing route, the oil was processed at 693 K and a hydrogen pressure of 15 MPa in the presence of an unsupported molybdenum sulfide catalyst. Both routes resulted in significant deoxygenation (97 wt% versus 93 wt%). It is feasible to co-refine pyrolysis oil using both methods, the main difference being that the hydroprocessing results in a significantly higher biogenic carbon yield from the pyrolysis oil to liquid and gaseous hydrocarbon products (92 wt%) but would in turn require input of H2. In the cracking route, besides the liquid product, a significant part of the biogenic carbon ends up as gas and as coke on the catalyst. The choice of route depends, among other factors, on the available amount of bio-oil and refining infrastructures. © 2023 The Authors

In order to successfully integrate biomass pyrolysis oils as starting materials for conventional oil refineries, upgrading of the pyrolysis oils is needed to achieve desired properties, something which can be performed either as part of the pyrolysis process and/or by separate catalytic treatment of the pyrolysis intermediate oil products. In this study, the quality of stem wood-derived pyrolysis oil was improved via ex situ catalytic hydropyrolysis in a bench-scale pyrolyzer (stage 1), followed by catalytic hydro-coprocessing with fossil co-feed in a laboratory-scale high pressure autoclave (stage 2). The effect of pyrolysis upgrading conditions was investigated based on the quality of intermediate products and their suitability for hydro-coprocessing. HZSM-5 and Pt/TiO2 catalysts (400 °C, atmospheric pressure) were employed for ex situ pyrolysis, and the NiMoS/Al2O3 catalyst (330 °C, 100 bar H2 initial pressure) was used for hydro-coprocessing of the pyrolysis oil. The application of HZSM-5 in the pyrolysis of stem wood under a N2 atmosphere decreased the formation of acids, ketones, aldehydes, and furans and increased the production of aromatic hydrocarbons and phenolics (guaiacols and phenols). Replacing HZSM-5 with Pt/TiO2 and N2 with H2 resulted in complete conversion of guaiacols and significant production of phenols, with further indications of increased stability and reduced coking tendencies.