Biomass Pyrolysis Oil Research Articles

Ternary phase behavior of phenol + toluene + zwitterionic alkaloids for separating phenols from oil mixtures via forming deep eutectic solvents

Phenols are important materials for the organic chemical industry. They mainly come from coal liquefaction oil, coal tar, petroleum and biomass pyrolysis oil, making the separation of phenols from oil mixtures of great commercial value. Two zwitterionic alkaloids, betaine and L-carnitine, biodegradable and environmentally benign ionic compounds, can efficiently separate phenols from oils by forming deep eutectic solvents (DESs). In this work, the phase equilibria of two ternary systems of toluene + phenol + betaine and toluene + phenol + L-carnitine were measured at 25.0 °C, 45.0 °C and 65.0 °C under atmospheric pressure. The phase behaviors of the two ternary systems were studied, which indicated that there were three kinds of phase regions: liquid, liquid-liquid, and liquid-liquid-solid. The separation of phenol from oil mixtures occurs at the latter two phase regions. Effects of temperature, zwitterionic alkaloid type and its dosage on the phase equilibrium were investigated. With decreasing temperature, the distribution and selectivity coefficients increase. L-carnitine shows better performance in separating phenol from oils via forming DES than betaine.

Trends in the Surface and Catalytic Chemistry of Transition-Metal Ceramics in the Deoxygenation of a Woody Biomass Pyrolysis Model Compound

The general surface chemical reactivity, surface reaction site nature, and van der Waals dispersion interaction capability of 10 transition metal ceramics were investigated in the catalytic reaction of guaiacol deoxygenation—a model compound for aromatics in woody biomass pyrolysis oil. A computational surface science approach has been applied to investigate Ti and Ni oxide, carbide, nitride, sulfide, and phosphide to ascertain the effect of element selection on surface and catalytic chemistry. The results indicated that systematic trends in surface chemistry are present in the transition-metal ceramics and that transition-metal phosphides present special balanced reactivity toward O, C, and H that results in their appreciable catalytic activity in deoxygenation reactions. The remaining ceramics were found to exhibit either too low or too high of reactivity toward oxygen, carbon, or hydrogen, which resulted in insurmountable thermodynamic and kinetic barriers for C–O bond cleavage or hydrogenation and the...

Characterization of the Water-Soluble Fraction of Woody Biomass Pyrolysis Oils

This paper reports a study of the chemical composition of the water-soluble (WS) fraction obtained by cold water precipitation of two commercial wood pyrolysis oils (BTG and Amaron). The fraction studied accounts for between 50.3 and 51.3 wt % of the oils. With the most common analytical techniques used today for the characterization of this fraction (KF titration, GC–MS, hydrolyzable sugars, and total carbohydrates), it is possible to quantify only between 45 and 50 wt % of the fraction. Our results confirm that most of the total carbohydrates (hydrolyzable sugars and nonhydrolyzable) are soluble in water. The ion chromatography hydrolysis method showed that between 11.6 and 17.3 wt % of these oils were hydrolyzable sugars. A small quantity of phenols detectable by GC–MS (between 2.5 and 3.9 wt %) were identified. It is postulated that the unknown high molecular weight fraction (30–55 wt %) is formed by highly dehydrated sugars rich in carbonyl groups and WS phenols. The overall content of carbonyl, carb...

Phase equilibria of phenol + toluene + quaternary ammonium salts for the separation of phenols from oil with forming deep eutectic solvents

Phenolic compounds (such as phenol, cresol sand xylenol), which are basic materials for the organic chemical industry, are mainly produced from coal liquefaction oil, coal tar, petroleum, and biomass pyrolysis oil. It has been reported that the separation of phenols from oil with forming deep eutectic solvents based on quaternary ammonium salt (QAS) is an efficient and environmentally friendly method. However, the phase equilibrium of QAS + phenol + oil mixtures has not been reported in the literature. In this work, the phase equilibrium for separating phenol from model oil with 2-hydroxy-N,N,N-trimethyl-ethanaminium chloride (ChCl), N,N,N-triethyl-ethanaminium chloride (TEAC), and N,N,N-trimethyl- methanaminium chloride (TMAC) was studied. Phase equilibria of three ternary systems of toluene + phenol + QAS were measured at 25.0, 40.0 and 65.0 °C, and phase behaviors of the ternary systems were studied. Effects of temperature, type and dosage of QAS on the equilibrium were investigated. The results show that low temperatures are beneficial to extraction of phenol and the phenol removal efficiency decreases with increasing temperature. Among the QASs, TEAC has the strongest ability to separate phenol, but the concentration of toluene entrained in the DES phase is the largest. Only TMAC is dissolved in the oil phase to a small extant, which can cause the loss of extractant. ChCl not only has high phenol removal efficiency, but also causes a small concentration of toluene entrained in the DES phase, which shows that ChCl is an efficient and environmentally friendly extractant.

Perspective on Catalytic Hydrodeoxygenation of Biomass Pyrolysis Oils: Essential Roles of Fe-Based Catalysts

Catalytic fast pyrolysis is the most promising approach for biofuel production due to its simple process and versatility to handle lignocellulosic biomass feedstocks with varying and complex compositions. Compared with in situ catalytic fast pyrolysis, ex situ catalytic pyrolysis has the flexibility of optimizing the pyrolysis step and catalytic process individually to improve the quality of pyrolysis oil (stability, oxygen content, acid number, etc.) and to maximize the carbon efficiency in the conversion of biomass to pyrolysis oil. Hydrodeoxygenation is one of the key catalytic functions in ex situ catalytic fast pyrolysis. Recently, Fe-based catalysts have been reported to exhibit superior catalytic properties in the hydrodeoxygenation of model compounds in pyrolysis oil, which potentially makes the ex situ pyrolysis of biomass commercially viable due to the abundance and low cost of Fe. Here, we briefly summarize the recent progress on Fe-based catalysts for the hydrodeoxygenation of biomass, and provide perspectives on how to further improve Fe-based catalysts (activity and stability) for their potential applications in the emerging area of biomass conversion.

An integrated process for the production of lignocellulosic biomass pyrolysis oils using calcined limestone as a heat carrier with catalytic properties

The production of upgraded bio-oils by an integrated process using a mixture of calcined limestone and sand as a heat carrier with catalytic properties was experimentally studied at pilot scale. The integrated process consisted of two main steps: biomass catalytic pyrolysis in an Auger reactor for bio-oil production and char combustion in a fluidised-bed combustor for heat carrier heating and regeneration. A temperature of 450°C was fixed as an optimum value to carry out the catalytic pyrolysis step. Temperatures ranging from 700 to 800°C were assessed in the char combustor. Process simulation demonstrated that solid recirculation from the combustor to the pyrolysis reactor was marginally affected in this temperature range. However, an optimum char combustion temperature of 800°C was selected from an environmental point of view, since lower polyaromatic emissions were detected whilst NOx emissions were kept under the legislation limits. Under designated conditions, several pyrolysis-combustion cycles were carried out. A moderate deactivation of the catalyst by partial carbonation was found. This fact makes necessary the incorporation of a purge and an inlet of fresh heat carrier in order to maintain the bio-oil quality in the integrated process.

Analysis of Karanja Seed Cake (Pongamia Pinnata) with the focus on Application of Pyrolysis oil as Fuel

Fluidized bed pyrolysis experiments have been conducted on a sample of Karanja seed (de-oiled) cake to determine the effects of particle size, pyrolysis temperature and nitrogen gas flow rate on the products yield. The particle size, pyrolysis temperature and nitrogen gas flow rate were varied from 0.175 to 1.6 mm, 400°C to 500°C and 6 LPM to 10 LPM. The maximum oil yield of 65.56 wt % was obtained at a nitrogen gas flow rate of 8 LPM, particle size of 0.5–0.99 mm and pyrolysis temperature of 450°C. The maximum gas yield of 38.20 wt % was obtained at particle size of 0.175–0.5 mm, nitrogen flow rate of 8 LPM and at 500°C. The maximum char yield of 24 wt % was obtained at 400°C. The gas fractions were obtained using gas analyzer. The pyrolysis gas fractions were found to contain hydrocarbon, nitrogen, oxygen, carbon dioxide and carbon monoxide. Water content of crude bio-oil and upgraded bio-oil was found 56% wt and 40 wt % respectively. The calorific value of up-graded Karanja bio-oil was found to be 16.5 MJ/Kg. Density, Viscosity and pH of upgraded bio-oil were found 1023Kg/m3, 3.25cst and 4.6 respectively. So, bio-oil can be used as a source of fuel if the water content of bio-oil could be reduced. Here an attempt has made to study the feasibility of production of valuable fuels from natural but non edible seed cake (Karanja) by the method of pyrolysis. Here the production of the fuel can serve purpose of alternative fuels as biomass pyrolysis oil has potential to be used as fuel oil or its substitute

Prediction of Properties and Elemental Composition of Biomass Pyrolysis Oils by NMR and Partial Least Squares Analysis

As with many substances derived from natural products, pyrolysis bio-oils are complex chemical mixtures and are extremely challenging to chemically characterize, requiring multiple separation and pretreatment steps followed by several different analytical techniques that need tedious adjustments and modifications when sample properties change. In this study, we present a way to simplify this analysis by using 13C NMR to characterize such substances as a whole without modification. Using partial least-squares (PLS) regression, we report what we believe to be the first reported use of 13C NMR to derive elemental composition information (mass fractions of C, H, N, and O) as well as the enthalpy of combustion (higher heating value), phenol and cresols concentrations, and the total acid number. Several PLS models were created correlating these various properties with the binned intensities of the 1H and 13C NMR spectra of 73 different samples consisting of pyrolysis bio-oils from various biomass sources and treatment protocols as well as finished fuels (gasoline, diesel, and biodiesel) and small molecule standards. Two models based exclusively on 13C NMR data demonstrated the best overall ability to predict these same properties for unknown samples. The R2 and RMSE of the predicted values are discussed in detail and are acceptable for many biofuel-related applications. That such properties and compositional measurements may be extracted from 13C NMR spectra is a direct result of the detailed chemical structural information influencing the chemical shifts and resonance patterns. Because these models were built using a wide range of samples and conditions, they are expected to also be useful for a wider range of applications.

Application of Waste Biomass Pyrolysis Oil in a Direct Injection Diesel Engine: For a Small Scale Non-Grid Electrification

Application of Waste Biomass Pyrolysis Oil in a Direct Injection Diesel Engine: For a Small Scale Non-Grid Electrification

Hydrotreating the Organic Fraction of Biomass Pyrolysis Oil to a Refinery Intermediate

The effect of the catalyst type, hydroprocessing conditions, and feed preparation on the mild hydrotreating of biomass pyrolytic lignin was examined. Pyrolytic lignin oils were produced by water separation at 1:1 and 3:1 water/oil mass ratios. Hydrotreating was performed in a semi-batch reactor at three severities using sulfided NiMo/Al2O3, Pd/C, and Pt/C catalysts. Over half of the carbon in the pyrolytic lignin could be converted to a low-oxygen (<5%), low-acid, volatile, hydrocarbon-miscible liquid product. This was achieved with all three catalysts at the most severe condition (400 °C and 2450 psig) and with Pt/C at somewhat less severe conditions. Nuclear magnetic resonance (NMR) analyses indicated that the remaining oxygen is largely phenolic in character. Hydrotreating of the organic fraction (pyrolytic lignin) gave oil with better properties, lower O and lower acidity, than hydrotreating of the whole oil at equivalent conditions.

Decarbonisation of olefin processes using biomass pyrolysis oil

Abstract An imperative step toward decarbonisation of current industrial processes is to substitute their petroleum-derived feedstocks with biomass and biomass-derived feedstocks. For decarbonisation of the petrochemical industry, integrated catalytic processing of biomass pyrolysis oil (also known as bio-oil) is an enabling technology. This is because, under certain conditions, the reaction products form a mixture consisting of olefins and aromatics, which are very similar to the products of naphtha hydro-cracking in the conventional olefin processes. These synergies suggest that the catalytic bio-oil upgrading reactors can be seamlessly integrated to the subsequent separation network with minimal retrofitting costs. In addition, the integrated catalytic processing provides a high degree of flexibility for optimization of different products in response to market fluctuations. With the aim of assessing the techno-economic viability of this pathway, five scenarios in which different fractions of bio-oil (water soluble/water insoluble) were processed with different degrees of hydrogenation were studied in the present research. The results showed that such a retrofit is not only economically viable, but also provides a high degree of flexibility to the process, and contributes to decarbonisation of olefin infrastructures. Up to 44% reductions in greenhouse gas emissions were observed in several scenarios. In addition, it was shown that hydrogen prices lower than 6 $/kg will result in bio-based chemicals which are cheaper than equivalent petrochemicals. Alternatively, for higher hydrogen prices, it is possible to reform the water insoluble phase of bio-oil and produce bio-based chemicals, cheaper than petrochemical equivalents.

An integrated process for biomass pyrolysis oil upgrading: A synergistic approach

Biomass pyrolysis is a promising path toward renewable liquid fuels. However, the calorific value of the pyrolysis oil (PO), also known as bio-oil, is low due to the high content of organic oxygenates and water. The oxygen content of PO can be reduced by hydrodeoxygenation, in which hydrogen is used to remove oxygen. An economic disadvantage of hydrodeoxygenation pathway is its dependence on hydrogen as an expensive feedstock. An alternative technology is to upgrade PO in hot, high pressure water, known as hydrothermal processing. The present paper studies upgrading pyrolysis oil derived from Norwegian spruce by (1) hydrodeoxygenation in a liquid hydrocarbon solvent using nanodispersed sulphide catalysts and (2) hydrothermal treatment in near-supercritical water. Experimental results and simulation studies suggested that if water soluble products are reformed for hydrogen production, the hydrodeoxygenation pathway would be a net consumer of hydrogen, whilst the hydrothermal pathway could produce a significant hydrogen excess. By comparison, the fuel yield from hydrodeoxygenation was significantly higher than hydrothermally treated fuel. Therefore, in the present study, an integrated model was proposed which demonstrates that the synergistic integration of hydrothermal and hydrodeoxygenation upgrading technologies can yield an optimal configuration which maximises fuel production, whilst obviating the need to purchase hydrogen. In this optimal configuration, 32% of raw pyrolysis-oil is hydrothermally treated and the rest is sent for hydrodeoxygenation. The results of a techno-economic analysis suggests that if the proposed integrated approach is used, it is possible to produce biofuel (43% gasoline, and 57% diesel) at a very competitive minimum selling price of 428 $ m−3 (1.62 $/gallon).

Properties of Oxygenates Found in Upgraded Biomass Pyrolysis Oil as Components of Spark and Compression Ignition Engine Fuels

Oxygenates present in partially hydroprocessed lignocellulosic-biomass pyrolysis oils were examined for their impact on the performance properties of gasoline and diesel. These included: methyltetrahydrofuran, 2,5-dimethylfuran (DMF), 2-hexanone, 4-methylanisole, phenol, p-cresol, 2,4-xylenol, guaiacol, 4-methylguaiacol, 4-methylacetophenone, 4-propylphenol, and 4-propylguaiacol. Literature values indicate that acute toxicity for these compounds falls within the range of the components in petroleum-derived fuels. On the basis of the available data, 4-methylanisole and by extension other methyl aryl ethers appear to be the best drop-in fuel components for gasoline because they significantly increase research octane number and slightly reduce vapor pressure without significant negative fuel property effects. A significant finding is that DMF can produce high levels of gum under oxidizing conditions. If the poor stability results observed for DMF could be addressed with a stabilizer additive or removal of im...

A Review of Physical Properties of Biomass Pyrolysis Oil

A Review of Physical Properties of Biomass Pyrolysis Oil

Variability in pyrolysis product yield from novel shrub willow genotypes

Fast pyrolysis is becoming a more attractive conversion option for the production of biofuels, due to the potential for directly producing hydrocarbon fuels seamlessly compatible with petroleum products (drop-in fuels). Dedicated bioenergy crops, like perennial grasses and short-rotation woody crops, will be among the major sources of biomass for fast pyrolysis. To aid in the advancement of fast pyrolysis conversion and to identify appropriate feedstock crops, novel genotypes of shrub willow recently bred for high yield were evaluated for pyrolysis product yield using pyrolysis-gas chromatography-mass spectroscopy (py-GC/MS). The goal of this study was to understand how variations in biomass composition impact pyrolysis conversion efficiency and pyrolysis oil (bio-oil) quality by analyzing the composition of the pyrolysis vapors by py-GC/MS. The results of the py-GC/MS analysis showed significant differences in products from both non-catalytic and catalytic pyrolysis carried out over zeolite catalyst (HZSM-5), which were correlated with differences in biomass composition. For non-catalytic conversion, the most significant relationships were between the syringyl:guaiacyl (S:G) ratio in the biomass and phenolic monomers, in addition to levoglucosan yields and cellulose content. Production of phenols, guaiacols, and syringols were largely independent of total lignin content, but were strongly related to the S:G ratio. Willow genotypes with low ash content and high cellulose content produced more liquid products and higher levels of deoxygenated aromatics following catalytic pyrolysis. These results demonstrate that it is possible to breed for improvements in biomass compositional traits that can ultimately lead to improvements in bio-oil yield and quality.

Maximizing the Stability of Pyrolysis Oil/Diesel Fuel Emulsions

Several emulsions consisting of biomass pyrolysis oil (bio-oil) in diesel fuel were produced and analyzed for stability over time. An ultrasonic probe was used to generate microscopic droplets of bio-oil suspended in diesel fuel, and this emulsion was stabilized using surfactant chemicals. The most stable emulsion was produced using a polyethylene glycol dipolyhydroxystearate (PEG-DPHS) surfactant, with a hydrophilic–lipophilic balance (HLB) number of 4.75 and a 32:8:1 ratio of diesel to bio-oil to surfactant, i.e., 20% utilization of bio-oil. This emulsion consisted of uniformly sized droplets with an average diameter of 0.48 μm, with no observed coalescence of droplets after 1 week. If left undisturbed, these droplets would slowly settle to the bottom of the mixture at a rate of only 2.4 mm/day, but this settling can be eliminated with slight mechanical agitation. This level of stability facilitates utilization of 20 wt % raw bio-oil in diesel as a renewable liquid fuel for spray combustion without the ...

Thermogravimetric analysis and fast pyrolysis of Milkweed

Pyrolysis of Milkweed was carried out in a thermogravimetric analyzer and a bubbling fluidized bed reactor. Total liquid yield of Milkweed pyrolysis was between 40.74% and 44.19wt% between 425°C and 550°C. The gas yield increased from 27.90wt% to 33.33wt% with increasing reaction temperature. The higher heating values (HHV) of the Milkweed bio-oil were relatively high (30.33–32.87MJ/kg) and varied with reaction temperature, feeding rate and fluidization velocity. The selectivity for CO2 was highest within non-condensable gases, and the molar ratio of CO2/CO was about 3 at the different reaction conditions. The 13C NMR analysis, of the bio-oil showed that the relative concentration carboxylic group and its derivatives was higher at 425°C than 475°C, which resulted in slightly higher oxygen content in bio-oil. The pH of aqueous phase obtained at 475°C was 7.37 which is the highest reported for any lignocellulosic biomass pyrolysis oils.

Progress in techniques of biomass conversion into syngas

Biomass gasification is one of major biomass utilization technologies to get high quality gas. The high quality gas can be subsequently used for gas supply and power generation as well as syngas. Significant efforts have therefore been made in biomass-derived syngas production. The paper reviews the state-of-the-art biomass-derived syngas production techniques in terms of technical performance. Various kinds of gasification reactor are briefly introduced. Main technologies of syngas production can be divided into four approaches: partial oxidation and steam reforming of biomass pyrolysis oils, co-gasification of biomass and coal, coupled steam hydrogasification of biomass and reforming of methane, gasification of biomass-derived char. Each of these production processes are also analyzed in detail. Among these production technologies, the primary technology for syngas production is steam hydrogasification and reforming. Syngas has a higher H2/CO ratio by using these two technologies: the steam hydrogasification and reforming technology and biomass-derived char technology.

Combustion performance of pyrolysis oil/ethanol blends in a residential-scale oil-fired boiler

A 40kWth oil-fired commercial boiler was fueled with blends of biomass pyrolysis oil (py-oil) and ethanol to determine the feasibility of using these blends as a replacement for fuel oil in home heating applications. An optimal set of test parameters was determined for the combustion of these blends with minimal soot and carbon monoxide formation. These set parameters were used to compare the performance of blends of ethanol with different concentrations of py-oil (10%, 20%, and 30% py-oil by mass) and py-oil produced from different biomass feedstocks, including switchgrass, miscanthus, eucalyptus, pennycress, forest residues, and soiled animal bedding, using #2 fuel oil as a control. Performance was measured in terms of the total heat input, the axial temperature profile of the combustion chamber, the gross heat output, and heat losses to the flue gas. Exhaust gas was analyzed for O2, CO2, CO, NOx, and total hydrocarbon concentration. It was found that a blend of 20% py-oil/80% ethanol could be used as a fuel in residential boilers with minimal retrofitting. This blend ratio produced no detectable change in the CO and hydrocarbon emissions compared to #2 fuel oil. When the py-oil fraction of this blend was produced from biomass with low amounts of nitrogen such as eucalyptus, NOx emissions were reduced by 12% compared to #2 fuel oil. When the py-oil was produced from proteinaceous feedstocks the py-oil stability improved but high nitrogen led to an order of magnitude increase in NOx emissions.

Biogasoline production by co-cracking of model compound mixture of bio-oil and ethanol over HSZM-5

Acids and ketones in biomass pyrolysis oil (bio-oil) can be readily cracked to produce hydrocarbons. They can also be enriched in the distilled fraction using molecular distillation techniques. To simulate the actual composition of the distilled fraction, the co-cracking performance of mixtures of hydroxypropanone, cyclopentanone, and acetic acid with ethanol in a fixed-bed reactor over an HZSM-5 catalyst was studied. The influences of reaction temperature and pressure on the reactant conversion, selectivity, and composition of the oil phase were investigated. At a low reaction temperature of 340 °C, the conversions of acetic acid and ethanol were as low as 67.9% and 74.4%, respectively, and the oil phase had a low hydrocarbon content of 59.8%, with large amounts of oxygenated byproducts. Cracking under atmospheric pressure also generated a low-quality oil phase with a very low selectivity of only 10.8%. Increasing the reaction temperature promoted reactant conversion and improved the deoxygenation efficiency, whereas increasing the reaction pressure significantly promoted hydrocarbon production. The optimum conditions for biogasoline production were 400 °C and 2 MPa. Under these conditions, the reactant conversion reached 100% and the oil phase selectivity was 31.5 wt%. This oil phase consisted entirely of hydrocarbons, 91.5 wt% of which were aromatic hydrocarbons, indicating that the HZSM-5 catalyst had high activity for deoxygenation and aromatization reactions during cracking. In addition, characterization of the spent catalysts and stability tests showed that the catalyst was deactivated after a long reaction time. However, the catalytic activity was recovered by catalyst regeneration.