Upgrading Of Pyrolysis Oil Research Articles

Thermo-kinetics and product analysis of the catalytic pyrolysis of Pongamia residual cake

Catalytic fast pyrolysis of Pongamia residual cake (PRC) and the kinetics of this were evaluated using thermogravimetry and pyrolysis-gas chromatography/mass spectrometry analyses. The influence of the heating rate on the devolatilization process was studied to obtain corresponding kinetic information. Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) model-free isoconversion methods were used to predict the kinetic parameters. The major thermal degradation of PRC occurred around 150–550 °C with an activation energy of 97.2–394.3 kJ/mol or 114.5–412.2 kJ/mol as determined by the KAS and FWO methods, respectively. Micro-scale pyrolysis trials were performed to determine the effects of the PRC particle size, reaction temperature and PRC: catalyst weight ratio on the pyrolytic product distribution and upgraded pyrolytic vapor properties for the 5 wt% Ni impregnated on activated carbon (AC), aluminium(III) oxide (Al2O3), kaolin and zeolite NaA supports. The results indicated that using a 1:5 PRC: Ni/AC catalyst weight ratio with medium-sized PRC particles (125–425 μm) was the most effective condition for the conversion of oxygenated (O)-compounds to hydrocarbons (HCs) through decarbonylation, decarboxylation and dehydration reactions, giving the highest decrease (99%) in O-compounds. Increased HC yields, to more than 58%, were also obtained with this catalyst. Similarly, using the other synthesized Ni catalysts resulted in a reduction in the O-compounds and production of favorable HC species, albeit to a lesser extent. Therefore, the catalytic pyrolysis process of this residue, especially with a Ni/AC catalyst, has the potential to be a viable option for producing upgraded pyrolysis oil, which may be applied as a quality alternative biofuel.

Production of Non-Conventional Fuels by Catalytic Cracking of Scrap Tires Pyrolysis Oil

Different commercial equilibrium fluidized catalytic cracking (FCC) catalysts have been tested in the upgrading of scrap tires pyrolysis oil (STPO) with the aim of obtaining automotive-like fuels. ...

Can Biofuels Help Provide Clean Propulsion for Shipping, Now and in the Future?

E4tech conducted an important study (in 2018) for the Dutch Biofuels Platform and the Port of Rotterdam, as part of the development of a roadmap for decarbonising shipping in the Netherlands. In particular, biofuels can provide large reductions in GHG and non-GHG emissions, with a range of solutions for decarbonisation in the short and longer term. They offer greater decarbonisation potential compared to fossil alternatives aimed at tackling air quality emissions (e.g. LNG). The biofuels analysed were hydro-treated vegetable oil (HVO – including from waste oils and fats), Fatty acid methyl ester (FAME), straight vegetable oil (SVO), ethanol (both conventional and advanced production processes), bio-methanol, bio-LNG, Fischer-Tropsch diesel (FT-diesel) and Upgraded Pyrolysis Oil (UPO). The study determined the most attractive biofuel options based on criteria such as GHG reduction potential, readiness of production, cost and compatibility with the current vessel fleet in each shipping sub-sector: deep-sea, short-sea and inland shipping. It also provided recommendation on coordinated interventions from the range of actors in shipping industry that can support the uptake of biofuels, overcoming a range of technical, economic and operational barriers to their use.

NiCuMo-SiO2 catalyst for pyrolysis oil upgrading: Model acidic treatment study

The main reasons of catalysts deactivation in hydro-processing pyrolysis liquids are by coke deposition, poisoning by bio-oil impurities (S, N, K, Cl, etc.), leaching of catalyst components, structural degradation in the presence of H2O, and sintering. The deactivation of catalysts by the acidity of the pyrolysis liquid is a specific concern, and this deactivation mechanism was studied by treating newly developed NiCuMo-SiO2 catalysts in 1 M acetic acid water solution (pH = 2–3). The activity of the acid-treated catalysts was subsequently investigated in the hydrodeoxygenation of gaseous propionic acid, in a tubular reactor at 225 °C with n-hexane and n-octane serving as diluent and internal standard, respectively.The samples treated by acid at different times (15–360 min) were characterized by X-ray diffraction (XRD), high resolution transition electron microscopy (HRTEM), X-ray fluorescence (XRF), CO chemisorption, N2 physical adsorption, and X-ray photoelectron spectroscopy (XPS). XRF and HRTEM studies together with the residual mass of catalyst pointed out at gradual leaching of catalyst components. Among the catalyst components, dissolution of nickel was the most pronounced, while molybdenum content decreased to a lesser extent. This is due to the formation of more acid stable molybdenum blues. The amount of copper decreased only slightly, due its higher electrochemical potential. Oxidation of metalliс species Cu and Ni is shown to obtain Cu2O, NiO and Ni(OH)2-like phases. Interestingly, the acidic treatment resulted in increasing active surface of the catalyst, nevertheless, the catalyst activity in propionic acid conversion irreversibly decreased in time by the acetic acid treatment due to loss of the active components (substantially nickel).

Hydrodeoxygenation of vanillin as model compound for pyrolysis oil over carboxylic carbon nanotubes-supported Ni catalysts

Hydrodeoxygenation (HDO) is one of the most promising technologies for the biomass pyrolysis oil upgrading, but substantial challenges for the development of efficient HDO catalysts still remain. In this work, the nickel catalysts supported on carboxylic carbon nanotube (Ni/CCNTs-X, X = 1, 2, 3, 4 and 5) with different diameter have been synthesized for the HDO of model compound (vanillin) to p-creosol. As the tube diameters of Ni/CCNTs-X catalysts increased, the catalytic activity increased firstly, and then decreased. The conversion of vanillin over Ni/CCNTs-4 catalyst reached up to 90.0% under mild reaction condition, with a concomitant 87.7% selectivity of p-creosol. The transformation pathway for the HDO of vanillin over Ni/CCNTs-X catalysts involve in hydrogenation, hydrogenolysis and etherification.

Effects of supercritical fluids in catalytic upgrading of biomass pyrolysis oil

The catalytic upgrading of biomass pyrolysis oil (bio-oil) was performed under supercritical conditions. The behaviors of solvents with MgNiMo/AC were investigated for use of methanol, ethanol, butanol, hexanol, and formic acid as supercritical fluids. The production of gases including hydrogen, carbon monoxide, carbon dioxide, and methane was analyzed, and changes in the compositions of esters, alcohols, and phenols were examined. When the catalyst dosage and temperature were increased, the production of hydrogen increased. Among the alcohols, methanol produced the highest amount of hydrogen, and butanol produced the lowest amount of hydrogen. Formic acid showed good hydrogen-production ability. After catalytic upgrading of bio-oil, there was a decrease in oxygen and moisture content and an increase in the higher heating value (HHV). With an extended reaction time, the oxygen content was lowered further. During the supercritical ethanol reaction at 340 °C under an initial 30 bar of N2 gas for 2 h the oxygen content decreased from 33.9 to 14.6 wt% and the HHV increased from 25.2 to 35.3 MJ/kg.

Pyrolysis of chlorine contaminated municipal plastic waste: In-situ upgrading of pyrolysis oils by Ni/ZSM-5, Ni/SAPO-11, red mud and Ca(OH)2 containing catalysts

This work is focussing to the thermo-catalytic batch pyrolysis of contaminated real municipal plastic waste using different catalyst mixtures in their different ratios: Ni/ZSM-5, red mud, Ca(OH)2 and Ni/SAPO-11, red mud, Ca(OH)2. The effect of the catalysts to the pyrolysis oil properties and the in-situ upgrading (especially the storage, transportation and corrosion stability) of pyrolysis oil was investigated. High concentration of Ni/ZSM-5 and Ni/SAPO-11 zeolites in catalyst mixtures can increase the yield of gases and pyrolysis oil, the concentration of aromatics or the hydrogen content in gases; however the presence of red mud in higher content can further increase the hydrogen concentration. ZSM-5 based catalysts showed higher efficiency in aromatization reactions. An accelerated aging test at 80 °C till 1 week was performed to investigate the storage and transportation stability of pyrolysis oils. Only slight increase was found in the density and viscosity, on the other hand there was a bit greater increase using SAPO-11 based catalysts than ZSM-5. The change in the olefin content was followed via bromine number and FTIR spectra of pyrolysis oil, which resulted ∼3% and ∼4% decreasing using Ni/ZSM-5 and Ni/SAPO-11 containing catalyst mixtures. Regarding acidic components, they significantly increased by aging time, while the high red mud and/or Ca(OH)2 in catalyst mixtures had notable benefit, because they can drastically decrease the concentration of chlorinated compounds, which led to less weight loss during corrosion test using copper plate till 60 days at 20 °C.

Life-Cycle Assessment of Alternative Pyrolysis-Based Transport Fuels: Implications of Upgrading Technology, Scale, and Hydrogen Requirement

Bio-oil produced from fast pyrolysis of biomass is a promising substitute for crude oil that can meet climate change mitigation goals, but due to its high oxygen content, it requires upgrading to remove oxygen in order to be used as a transportation fuel. Hydrodeoxygenation (HDO) is one means of upgrading fast pyrolysis oil; however, its main limitation is its large hydrogen requirement. We evaluate an alternative electrochemical deoxygenation (EDOx) method that uses catalytic electrode membranes on a ceramic, oxygen-permeable support to generate hydrogen in situ for deoxygenation at the cathode and oxygen removal at the anode. We analyze the life-cycle greenhouse gas (GHG) emissions and scale effects of gas-phase upgrading of pyrolysis oil [300 t/day (MTPD)] using different configurations of EDOx and compare it with the large-scale HDO process (2000 MTPD). We observe that the EDOx configurations have lower total GHG emissions of 5–8.4 and 7.4–11 g of CO2 equiv/MJ for vehicles operated with diesel and gasoline, respectively, compared to HDO (39 g of CO2 equiv/MJ). Furthermore, the EDOx processes offers potentially 10 times more small-scale pyrolysis upgrading facilities in the United States compared to HDO, suggesting that small-scale on-site EDOx processes can reach more inaccessible forest biomass resources.

Pyrolysis oil polymerization of water-soluble fraction during accelerated aging

Pyrolysis oil is a promising material for renewable energy through a hydrogenation process. However, the polymerization, initiated especially by pyrolysis oil water-soluble fraction (PS), is a big hurdle to hydrogenation. The types and structures of the polymerization chemicals, their polymerization mechanisms are very important for upgrading pyrolysis oil. This study firstly compared the polymerization rates of water-soluble fraction (PS) and water-insoluble fraction (PL) by accelerating aging fresh PS and PL at different temperatures (80 °C, 90 °C, 100 °C and 110 °C) for 24 h and at 110 °C for different durations (12 h, 24 h, 36 h, 48 h and 60 h), respectively. The thermogravimetric and differential thermogravimetry analysis results showed that PS polymerized much more rapidly than PL. Then, PS polymerization was further investigated by evaluating the changes in its physical properties (water content, viscosity and element content) and chemical compositions (gas chromatography and liquid chromatogram) before and after aging. The results showed that hydroxy aldehydes and ketones (especially glycoaldehyde, hydroxyacetone and levoglucosan), dicarbonyl compounds (especially succindialdehyde) and α, β-unsaturated carbonyl compounds (especially 3-methyl-2-cyclopenten-1-one and dehydrate resultants of some aldol condensation products) were mainly responsible for PS polymerization.

Progress Towards Electrochemical Methods for Pyrolysis-Oil Hydrogenation

Liquid fuels generation via flash pyrolysis of biomass followed by thermochemical upgrading has been a research topic for many years. The pyrolysis-oil produced from this process is a complex mixture of hundreds of organic and inorganic compounds. The reactive species in pyrolysis-oil complicate storage, transportation, and downstream processing because of secondary reactions. Currently these oils require a complex three-stage process operating at moderate temperatures between 433 and 678 K, and high hydrogen pressures of up to14,000 kPa. The process economics are limited by the high temperature and high pressure hydrogen requirement. Recent research suggests that the hydrogenation reactions can be performed using electrochemical reactors operating at much lower temperatures and pressures (293 K and 101 kPa) with no supplied dihydrogen. We have been exploring electrocatalytic upgrading of pyrolysis oil. Early tests show the feasibility of pyrolysis oil upgrading when tested in a flow cell configuration. 13C NMR and 1H NMR indicates a significant decrease in carbonyl and aromatic species post electrolysis (Figure 1) illustrating the viability of the approach. To better understand the influence of electrode catalysts on kinetics, probe molecules and probe molecule mixtures are being tested. The results indicate that Pd is the most active catalyst for electrochemical reduction of aldehydes and ketones, but was inactive for phenol reduction. However, Rh catalysts were active for phenol, but had lower activity for aldehyde and ketone reactions. Based on this research, a bi-metal catalyst is being developed and the experimental results will be presented. Reaction kinetics as well as the impact of site competition in mixtures will be discussed. Figure 1

SO42−/ZrO2 as catalyst for upgrading of pyrolysis oil by esterification

Pyrolysis oil of rubber seed oil (RSO) was upgraded by methyl esterificationusingSO42−/ZrO2 solid acid as catalyst. The activity and reusability of SO42−/ZrO2 solid acid were investigated and the experiment indicated that the esterification rate could reach 99.62% and was still above 95% in the third reaction. The component of SO42−/ZrO2 solid acid changed little after the third used. The properties of the obtained biofuel were studied and the results showed they were superior to pyrolysis oil and biodiesel, and similar to 0# diesel. The methyl esterification reaction kinetics was researched. The kinetics calculation indicated that the reaction order of the methyl esterification is 1.058, and Arrhenius equation can be expressed as k1=7.711×106e-47.913RT.

Enhancing Cooperativity in Bifunctional Acid–Pd Catalysts with Carboxylic Acid-Functionalized Organic Monolayers

Cooperative catalysts containing a combination of noble metal hydrogenation sites and Bronsted acid sites are critical for many reactions, including the deoxygenation (DO) of biomass-derived oxygenates in the upgrading of pyrolysis oil. One route toward the design of cooperative catalysts is to tether two different catalytically active functions so that they are in close proximity while avoiding undesirable interactions that can block active sites. Here, we deposited carboxylic acid (CA)-functionalized organophosphonate monolayers onto Al2O3-supported Pd nanoparticle catalysts to prepare bifunctional catalysts containing both Bronsted acid and metal sites. Modification with phosphonic acids (PAs) improved activity and selectivity for gas-phase DO reactions, but the degree of improvement was highly sensitive to both the presence and positioning of the CA group, suggesting a significant contribution from both the PA and CA sites. Short spacer lengths of 1–2 methylene groups between the phosphonate head and ...

Mesoporous zeolites for biofuel upgrading and glycerol conversion

With the recent emphasis and development of sustainable chemistry, the conversion of biomass feedstocks into alternative fuels and fine chemicals over various heterogeneous catalysts has received much attention. In particular, owing to their uniform micropores, strong acidity, and stable and rigid frameworks, zeolites as catalysts or co-catalysts have exhibited excellent catalytic performances in many reactions, including hydrodesulfurization, Fischer-Tropsch synthesis, and hydrodeoxygenation. However, the relatively small sizes of the zeolite micropores strongly limit the conversion of bulky biomolecules. To overcome this issue, mesoporous zeolites with pores larger than those of biomolecules have been synthesized. As expected, these mesoporous zeolites have outperformed conventional zeolites with improved activities, better selectivities, and longer catalyst lives for the upgrading of pyrolysis oils, the transformation of lipids into biofuels, and the conversion of glycerol into acrolein and aromatic compounds. This review briefly summarizes recent works on the rational synthesis of mesoporous zeolites and their superior catalytic properties in biomass conversion.

Mild Upgrading of Bio-Crude Pyrolysis Oil: A Concept Based on Bio-Based Alcohols with Selective Water Adsorption

Biocrude pyrolysis oil is obtained by a process called fast-pyrolysis, in which almost any organic-based feedstock is thermally processed at moderate temperatures, in the range of 400–600 °C, in the absence of oxygen at short residence times. After condensing the vapors in a cooling tray, a dark-brown bioliquid is obtained. The quality of the thus obtained fast pyrolysis oil has some barriers for its direct use as transportation fuel. Low caloric value, high viscosity, and corrosion are the major challenges for its implementation in conventional engines. There have been sustained efforts to improve the quality of the oil. In this Communication we are reporting a concept on improving the acidic properties by means of a combined catalysis and adsorption approach. We found that fast pyrolysis oil can be upgraded through alcoholysis using n-butanol and tetrahydrofurfuryl alcohol, which are biomass-derived bulk chemicals. The reaction is acid catalyzed whereas water is continuously separated from the condensate mixture through molecular sieve adsorption. Under optimal conditions, the ultimate acidity and water content of the upgraded product are negligible.

Upgrading of pinyon-juniper catalytic pyrolysis oil via hydrodeoxygenation

Abstract In this study we discuss hydrodeoxygenation (HDO) of pinyon juniper (PJ) catalytic pyrolysis oil over Ni/SiO2 Al2O3 catalyst in a batch reactor to improve the physicochemical properties of the oil. The influence of temperature (350–500 °C), reaction time (15–90 min), and initial hydrogen pressure (3.5–10 MPa), on hydrodeoxygenation of PJ pyrolysis oil was investigated. After hydrogenation was completed, gas, coke, and a liquid product of two immiscible phases (aqueous and organic), were obtained. Maximum HDO of bio-oil was achieved at 450° C while the initial hydrogen pressure was 7 MPa and the reaction time was 30 min. Under these conditions, the H/C and O/C atomic ratios changed from 1.29 to 0.29 respectively for bio-oil to 2.36 and 0 for HDO oil respectively. The higher heating value increased from 27.64 MJ/kg of bio-oil to 45.58 MJ/kg of upgraded oil. The water content of organic liquid product was less than 0.05 wt% while it was 1.63 wt% in the feed. The viscosity of upgraded oil was 1.26 cP compared to119 cP for the crude bio-oil.

Two-step continuous upgrading of sawdust pyrolysis oil to deoxygenated hydrocarbons using hydrotreating and hydrodeoxygenating catalysts

The two-step hydrodeoxygenation of pine sawdust pyrolysis oil, or bio-oil, is performed using pairs of first-step hydrotreating and second-step hydrodeoxygenating catalysts. The reaction results demonstrate that the combination of hydrotreating carbon-supported 5wt% Pd (5wt% Pd/C) and hydrodeoxygenating tungstate-zirconia-supported 3wt% Ru (3wt% Ru/WZr) catalysts produced the highest yield of oil products and the lowest yield of cokes and tars. The hydrodeoxygenated liquid products are further analyzed using FT-IR, which indicates the removal of carbonyls and hydroxyls along with an increase of methyls. The roles of hydrotreating Pd/C are further studied using GC/MS results of the hydrotreated liquid products; these results indicate that the hydrogenation of carbonyls to alcohols and the saturation of furans occur during the first step of the hydrotreating process. The removal of carbonyls and unsaturated furans can suppress their strong adsorption to noble metal surfaces and then their carbonization to cokes.

Ex-situ catalytic upgrading of vapors from microwave-assisted pyrolysis of low-density polyethylene with MgO

Ex-situ catalytic upgrading of vapors from microwave-assisted pyrolysis of LDPE using MgO as the base catalyst was investigated and the effects of catalyst to reactant ratio, pyrolysis temperature, and catalytic reaction temperature on the yields and chemical profiles of products were examined. 24.2–38.5wt.% of ex-situ upgraded liquid yield were obtained under varied reaction conditions. Productive gas yield (higher than 56.6wt.%) and low solid residue yield (less than 7.1wt.%) were obtained as long as the pyrolysis temperature was over 500°C during the ex-situ upgrading process. The coke yield was negligible, ranging from 0.14wt.% to 1.94wt.% based on LDPE mass. The conversion of alkenes to aromatics was improved at higher catalyst to feedstock ratios, higher pyrolysis temperatures, and higher catalytic reaction temperatures. The total percentage of gasoline fraction in the upgraded pyrolysis oil ranged from 79.5% (37.3% mono-aromatics and 42.2% C5-C12 aliphatics) to 96.0% (39.7% mono-aromatics and 56.3% C5-C12 aliphatics) under various conditions, compared with 10.5% mono-aromatics and 30.2% C5-C12 aliphatics from non-catalytic pyrolysis. The main composition of gas product was hydrogen, C1-C3 olefins and paraffins, varying with reaction condition. Both free radical and carbanion mechanisms for the conversion of LDPE with MgO were proposed.

Evolution of Functional Groups during Pyrolysis Oil Upgrading

In this work, we examine the evolution of functional groups (carbonyl, carboxyl, phenol, and hydroxyl) during hydrotreatment at 100–200 °C of two typical wood derived pyrolysis oils from BTG and Amaron in a batch reactor over Ru/C catalyst for reaction time of 4 h. An aqueous and an oily phase were obtained. The contents of the functional groups in both phases were analyzed by GC/MS, 31P NMR, 1H NMR, CHN, KF titration, UV fluorescence, carbonyl groups by Faix and phenols by Folin−Ciocalteu method. The consumption of hydrogen was between 0.007 and 0.016 g/(g of oil), and 0.001–0.020 g of CH4/(g of oil), 0.005–0.016 g of CO2/(g of oil), and 0.03–0.10 g of H2O/(g of oil) were formed. The contents of carbonyl, hydroxyl, and carboxyl groups in the volatile GC-MS detectable fraction decreased (80, 65, and ∼70%, respectively), while their behavior in the total oil and hence in the nonvolatile fraction was more complex. The carbonyl groups initially decreased having a minimum at ∼125–150 °C and then increased, wh...

Upgrading of fast pyrolysis oil via catalytic hydrodeoxygenation: Effects of type of solvents

Effects of type of solvents (hydro-treated bio-oil and ethanol) and temperature (300 and 350 °C) on hydrodeoxygenation (HDO) of fast pyrolysis oil (PO) were studied. The presence of a solvent effectively reduced self-polymerization of the intermediates during the bio-oil HDO process. HDO of PO using hydro-treated oil as the solvent produced higher yields of oil fraction (OF) and consumed more H2 than those with ethanol. While the OF yields from all the HDO experiments ranged from 60 to 90 wt%, the highest OF yield was obtained using hydro-treated bio-oil as the solvent. Nevertheless, HDO of PO in ethanol is more promising as it improves the HHV (higher heating value) of the bio-oil substantially (from 21 to 38 MJ/kg), reduces the molecular weight of bio-oil, and the resulted OFs have the lowest O/C value (0.08). HDO upgrading of bio-oil in ethanol has similar effects as HDO operation at a higher temperature (350 °C) without solvent with respect to molar mass reduction for the bio-oil.

Upgrading of sawdust pyrolysis oil to hydrocarbon fuels using tungstate-zirconia-supported Ru catalysts with less formation of cokes

Abstract Using a continuous flow reactor, bio-oil prepared by the pyrolysis of sawdust was upgraded to produce petroleum-like deoxygenated hydrocarbon fuels. Dispersed tiny bio-char particles in the raw bio-oil were removed by extraction using diethyl ether to suppress solid-particle-nucleated coking. Noble metal catalysts, instead of molybdenum-based catalysts, were selected to avoid the continuous addition of sulfur compounds. Among the catalysts, tungstate-zirconia-supported Ru catalysts (Ru/WZr) exhibited high hydrodeoxygenation activity and less formation of cokes, which characteristics are important in the development of feasible upgrading processes. The investigation of catalysts used in this study demonstrates that the larger quantity of Bronsted acid sites compared to Lewis acid sites suppresses the formation of cokes.