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Review of fast pyrolysis of biomass and product upgrading
... Plywood is a very durable composite material; it is waterproof and is heavier than MDF [4]. Plywood has very good strength in relation to its weight and presents superior rigidity on both of it sides [10][11][12][13][14][15][16][17][18][19]. It can be used as a structural material, in which case its dimensions and properties must be precisely calculated [20]. ...
... The water absorption percentage depends on the structure of the two materials (PW and MDF) [12]. Thus, for poplar PW, it is observed that the water absorption for 2 h was higher than the control sample in the case of the T 1 t 1 regime (with 72.73%), while in the case of the T 2 t 1 regime, the water absorption for 2 h was lower than the control sample (with 14.62%). ...
... Only the swelling in thickness was used, because the swelling in the longitudinal direction was very small, almost imperceptible. This behavior is very well known from the properties of solid wood, where the ratio between the two directions is 1: (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). ...
In a context where there is an increasing need for thermal treatments of wooden products, the current research contributes a description of the torrefaction treatment of two of the composite wood materials available on the international market. The present paper presents the importance of the torrefaction process for poplar plywood and medium-density fiberboard. In this paper, the positive aspects of the torrefaction process (decrease in water absorption, thickness swelling and shrinkage, and color) but also the negative aspects of mechanical resistance to static bending are presented. Poplar plywood (PW) and medium-density fiberboard (MDF) panels, with the initial dimensions of 2000 × 1250 mm, were used. From these, 300 × 300 mm samples were cut and torrefied using two different temperatures (170 and 190 °C) and two different periods (for 1 and 2 h). After the treatment, the samples were cut in different sizes (as necessary for each type of evaluation method) from different zones of the panels and used to evaluate the water absorption and thickness swelling, to determine their modulus of rupture, roughness, and color changes. The obtained results emphasize that the mass loses increase at high temperature as the main disadvantageous characteristics of torrefaction. Also, while the calorific power increases with the increase in the parameters of the torrefaction regime, the hygroscopicity and some mechanical properties of the material simultaneously decrease.
... Bio-oil is a mixture of over 200 different types of major and minor organic compounds, and is a source of some pure chemicals including phenol, organic acids, alcohol, and aldehyde, among others [12]. It typically comprises 50 − 65 wt.% organic components, including acids, aldehydes, ketones, furans, phenolics, guaiacols, syringols, and sugars; 15 − 30 wt.% moisture; and 20 wt.% colloidal fraction [13]. These compounds' oxygen content results in detrimental characteristics such as reduced energy density, instability, high viscosity, and corrosion [14]. ...
... This is substantiated by a prior study [35], which proved that higher pyrolysis temperatures enhance the reduction of oxygen content while increasing carbon and hydrogen. In Yellow Dodolla Holetta-1 Raw Bio-oil [32] Hydroprocessed [34] Moisture content (%) 35 0.170 ± 0.00 0.208 ± 0.01 0 − 0.2 [13] < 0.001 addition, previous studies proved that [36], thermal treatment of lignocellulosic biomass leads to the formation of H 2 -rich gas. The concentration of C and H were compared to previous results in which their contents were determined to be considerably higher than those of the wood pyrolysis bio-oil, which had values of C (54 − 58%), H (5.5 − 7.0%), respectively, [11]. ...
Bio-oils produced through thermochemical conversion processes such as pyrolysis from streamside products obtained from a bio-jet fuel production facility may be used as promising low-carbon alternative feedstocks in the aviation industry. The present investigation applied slow pyrolysis that was conducted at different temperatures to produce bio-oils from hexane-defatted Brassica carinata oilseed meals. The pyrolysis experiments proved that the highest temperature (550℃) produced the maximum bio-oil yield (55.01%), while the lowest temperature (350℃) produced the maximum bio-char (34.93%) and gas (45.84%) yields. An in-depth characterization was performed on the bio-oils to investigate whether they may be employed as alternative feedstocks for bio-jet fuel production. As a result, properties were studied using physicochemical characterization, ultimate analysis, atomic ratios analysis, heating value analysis, inductively coupled plasma-optical emission spectrometry analysis, gas chromatograph-mass spectroscopy, and Fourier-transform infrared spectroscopy. The characterization results of the bio-oils revealed that they had moisture (35.38 − 48.64%), pH (8.50), kinematic viscosity (14.10 − 16.05 cSt), ash content (0.17 − 0.208%), carbon (55.4 − 62.3%), hydrogen (9.02 − 9.29%), nitrogen (6.08 − 6.20%), sulfur (0.61 − 0.69%), oxygen (21.47 − 28.56%), and higher heating value (26.98 − 30.45 MJ/kg). Furthermore, it was found that the major classes of compounds identified include saturated hydrocarbons (13.56 − 14.52%), saturated fatty acids (2.33 − 3.67%), monounsaturated hydrocarbons (30.28 − 34.62%), monounsaturated fatty acids (6.54 − 11.23%), polyunsaturated fatty acids (1.41 − 2.82%), and Others (such as nitrogenated compounds) (38.44 − 39.62%). In conclusion, because of their remarkable excellent characteristics, and because they can be catalytically upgraded into advanced fuels by catalytic hydrotreatment methods (like hydrodeoxygenation and hydrodenitrogenation), and hydrocracking reactions, the oils can be used as promising alternative feedstocks for the aviation industry.
... Such a promising option is mobile fast pyrolysis which can transform biomass found in dispersed locations, into bio-oil, a denser and higher energy content product which can be used in many applications directly or as an energy carrier after upgrading [4,5] . Except biooil, fast pyrolysis always produces syngas and biochar at related proportions which can vary depending various process conditions, such as biomass type, reactor type, temperature, additives, catalysts, residence time, and pressure [4,6]. ...
... Such a promising option is mobile fast pyrolysis which can transform biomass found in dispersed locations, into bio-oil, a denser and higher energy content product which can be used in many applications directly or as an energy carrier after upgrading [4,5] . Except biooil, fast pyrolysis always produces syngas and biochar at related proportions which can vary depending various process conditions, such as biomass type, reactor type, temperature, additives, catalysts, residence time, and pressure [4,6]. ...
Biomass presents several logistical challenges in the upstream supply chain, mainly due to seasonal availability and geographical dispersion. The currently prevalent supply chain modelling practice for biofuel production involves a centralized fixed facility to exploit economies of scale. However, the increased cost of transporting biomass from dispersed locations may affect the viability of the biomass supply chain, while leaving some potential biomass production locations unutilized. This is particularly pronounced when there is no densification stage of the biomass foreseen before transportation, and in cases where the biomass availability is characterized by high geographical dispersion such as biomass cultivated on marginal land, contaminated land, or biomass that is a by-product or waste (second generation biofuels). In this study, we investigate the potential benefits of considering a mix of fixed and mobile fast pyrolysis units for biofuel production engaging an optimization methodology. The mobile units aim to convert biomass to intermediate products (biofuel precursors) with higher density, making them storable and easier and more cost effective to be transported to centralized facilities, where upgrading and conversion to the final product (biofuel) takes place.
... Pyrolysis that usually takes place under mediate temperature and inert atmosphere can continuously convert distributed biomass with a low energy density into liquid bio-oil, biochar and pyrolysis gas that are relatively easier for storage and transportation in an industrial scale [4,5]. Bio-oil has the potential to be further upgraded to drop-in fuels or value-added commodity chemicals [6,7]. ...
... Thus, pyrolysis technology has attracted growing interests recently. Due to the complex structure and high oxygen content of biomass feedstock, however, the raw bio-oil derived from biomass pyrolysis alone has some undesirable properties, such as high oxygen content, high acidity, low heating value, poor thermal stability and so on, limiting its direct application and bringing challenges to the upgrading processes [4]. ...
Co-pyrolysis of lignocellulosic biomass and hydrogen-rich petroleum-based polyolefin plastics is a promising to way to improve bio-oil quality and alleviate the waste plastic pollution issues. In this study, co-pyrolysis of pinewood and HDPE was systematically investigated. The addition of HDPE decreased yield of char and gas while increased that of bio-oil, enhancing the selectivity to alcohols and hydrocarbons. The most obvious synergistic effect was observed at the HDPE mixing proportion of 0.25, at which hydrocarbon selectivity derived from co-pyrolysis experiments was 41.19% higher than the calculated weighted average values. As pyrolysis temperature increased from 500°C to 700°C, the yield of bio-oil from co-pyrolysis at the HDPE mixing proportion of 0.25 decreased from 69.11 wt.% to 50.33 wt.%, alkanes selectivity decreased from 27.41% to 3.67% and olefins selectivity increased from 14.96% to 47.12%. At 700°C, aromatics started to produce with a selectivity of 15.50%. The surface morphologies of char were not significantly affected by the HDPE mixing proportion and pyrolysis temperature. The thermogravimetric analysis results revealed that the global co-pyrolysis process can be divided into two major degradation stages, based on which multi-step method was adopted to analyze the kinetics of the process. The average apparent activation energies of stage I and stage II were 167.73 kJ/mol and 274.74 kJ/mol, respectively. The results from this work provide a theoretical guide for further development of co-pyrolysis of pinewood and high-density polyethylene (HDPE).
... Pyrolysis produces tars, fumes, and char after a longer residence period and less intense heat (Fakhrhoseini & Dastanian, 2013). Pyrolysis does not need flue gas cleaning since it is often treated before use (Bridgwater, 2012). Additionally, it creates critical components for petrochemical and petroleum refining operations, which might compromise petroleum processing reliability (Heikkinen et al., 2004). ...
This study presents a comprehensive parametric investigation focusing on the pyrolysis and in-line reforming of High-Density Polyethylene (HDPE) at zero time on stream. The research explores the impact of varying operating parameters, specifically examining the effects of temperature, space time, and steam/plastic (S/P) ratio on conversion, hydrogen production, and product yields. The temperature was varied within the range of 600–750 °C, demonstrating notable influence on conversion efficiency and hydrogen production. Additionally, the effect of space-time (2.8–20.8 g catalyst min gHDPE−1) was thoroughly evaluated, revealing substantial improvements in both conversion and hydrogen yields. Moreover, the S/P ratio of 1 to 3 was investigated, showcasing significant enhancements in hydrogen and CO2 yields with increasing steam partial pressure. The study provides valuable insights into optimizing the process parameters for HDPE pyrolysis and in-line reforming, which are crucial for achieving efficient conversion and enhancing hydrogen production.
... Furthermore, in a study with baru mesocarp, whose chemical composition is similar to that of açaí seeds, with 11% extractives and 31% lignin [59], the bio-oil obtained at 723 K for 30 min demonstrated this representation of fatty acids and phenolic compounds [60]. However, oxygenated compounds in the bio-oil make it unstable and of low miscibility with hydrocarbons, and thus, performing a physical, chemical, or catalytic improvement is indicated [61]. Recent advances have been made with hydrodeoxygenation processes for the conversion of phenols [35] and biomasses rich in fatty acids [62]. ...
Pyrolysis converts biomass into other biofuels and is an alternative for residue management. This study aimed to investigate the kinetics of pyrolysis of açaí seeds and to bring insights into the slow pyrolysis of their briquettes. The thermogravimetric analysis was performed in an N2 atmosphere with a final temperature of 1173 K. It tested heating rates of 2, 5, 10, 15 and 20 K min−1. We determined the kinetic triplet using the isoconversional models of Friedman, Ozawa–Flynn–Wall, modified Coats–Redfern, Starink, and Vyazovkin, and the master plots method. In addition, slow pyrolysis occurred in a fixed-bed reactor coupled with a cooling system. The bio-oil yield was optimized via response surface methodology, and the compounds were identified with the support of gas chromatography coupled with mass spectrometry. The isoconversional model of Ozawa–Flynn–Wall showed activation energy of 165.59 kJ mol−1, with the slightest deviation value. The average percentage deviation between theoretical and experimental master plots corresponded to second-order random nucleation. At last, the global activation energy value was 134.76 kJ mol−1, and an Arrhenius pre-exponential factor was 1.11 1010 s−1, with R2 = 0.96. For slow pyrolysis, it observed an inflection point at 715 K and 11.93 K min−1. We concluded that the second-order reaction mechanism represents the pyrolysis of the açaí seed. In addition, the bio-oil yield maximizes at milder temperatures with high heating rates or high temperatures with low heating rates. These production parameters affect the bio-oil composition.
... The pH of OP was 4.43-4.49 which was less acidic compared to fast pyrolysis oil of less 2.5 reported in literatures [49][50][51], more acid than biodiesel of 6-9 [52] and diesel of 5.5-8.5 [53], and hence a necessity for upgrading. The OP density was 0.984-1.089 ...
Cashew nut shells (CNS) are an underutilized agricultural residue generated in large quantities. The study aimed at modeling and optimizing of intermediate pyrolysis (IP) process using response surface methodology of Box-Bohnken method (RSM-BB). Batch experiments were conducted in a fixed-bed reactor to pyrolyze CNS at various particle sizes (1–10 mm), residence times (20–60 min), heating rates (1–10 °C/min), and temperatures (400–600 °C). Ten responses were modeled and optimized to co-produce adsorption carbon and OP as fuel. Co-production occurred at 1–1.7-mm particle size, 22-min residence time, 2.03 °C/min heating rate, and 470 °C temperature. The above optimal parameters gave the yields of biochar, bio-oil, OP, and gas to be 36.52%, 40.9%, 27.8%, and 22.6%, respectively. The analysis of OP revealed that it exhibited pH of 4.65, moisture content of 2.68%, heating value of 26.7 MJ/kg, and density of 1.09 g/cc which were not in the range of values of fossil diesel. Adsorption biochar produced had gold adsorption capacity of 1.86 mgAu/g which was lower than that commercial activated carbon (3–15 mgAu/g). The study demonstrated that IP has potential for valorizing CNS into value-added biochar and OP.
... Type of pyrolysis reactors used in OPB pyrolysis[46][47][48]. ...
Malaysia is one of the leading producers and exporters of oil palm, and the industry contributes significantly to the growth of the national economy. Nonetheless, the consequential oil palm biomass (OPB) with a potential yield of ~97 million tonnes annually presents both challenges and opportunities, demanding innovative waste management solutions. This paper explores the feasibility of converting OPB into valuable commodities by employing concentrated solar-driven pyrolysis. A detailed overview of the biomass produced from oil palm plantations and mills is provided, along with a discussion of the industry stakeholders and associated biomass management challenges. The pyrolysis of OPB is explored, emphasizing benefits, potential barriers, and techniques. The focus then shifts to Malaysia's solar potential, which ranges from 1470 to 1900 kWh/m 2 annually. The potentials of solar pyrolysis are explored, encompassing discussions on solar concentrator types, reactors, and the distribution of solar and OPB resources throughout Malaysia. The paper then recommends Tawau in Sabah, as an ideal location for OPB solar pyrolysis, due to its solar availability (up to 1873 kWh/m 2), potential OPB resources from 19 mills and 241 plantations, and supportive infrastructure. The paper proposes solar-driven pyrolysis as a sustainable solution for Malaysia's OPB management, offers insights for policy initiatives and technological innovations in optimizing OPB and solar energy utilization.
... One of the types of pyrolysis is fast pyrolysis, in which biomass is decomposed quickly at temperatures of approximately 500 C with a short residence time to maximize the yield of liquid biooil [85]. Slow pyrolysis is characterized by a very low heating rate of about 0.1 K/s and a long residence time [86], resulting in higher char yield. ...
Bioenergy has developed escalating intrigue over the years, given its carbon neutral characteristics. The increasing concern about harmful environmental effects sparked by the extensive application of non-renewable energy sources necessitates the contribution of bioenergy to the global renewable energy mix. Bioenergy is produced by the oxidation of biomass substrates which are categorized as first generation (edible food sources), second generation (non-edible sources), and third generation (biomass derived from algae). Although rapid growth, abundant existence, cultivability in non-arable lands and low processing energy provides algal substrates with an edge over others, their large-scale conversion processes still require extensive development. Biomass can be transformed into bioenergy by a myriad of conversion processes that are biological, chemical, and thermal in nature. Biofuels such as bioethanol, biogas, and biodiesel can be produced by fermentation (biological process), anaerobic digestion (biological process), and transesterification (chemical process), respectively. Thermal conversion processes include gasification and combustion of biomass to produce energy. Additionally, several pretreatment methods to condition the flow of the biomass substrate, thereby ensuring increased conversion efficiency of the process, have been discussed in the paper. Although hybrid conversion processes provide the luxury of broader biomass feedstock intake, increased processing time and larger production area are some of the challenges that require unraveling to attract investors.
... Pyrolysis is a thermochemical decomposition process that involves the heating of organic materials in the absence of oxygen to produce useful products such as biochar, bio-oil, and pyrolytic gas and their distribution depends on the operating parameters of the reaction (Bridgwater 2012). The specific products obtained depend on factors such as temperature, residence time, pressure and the nature of the biomass, as well as other reactor conditions (Kesari et al. 2021;Sekar et al. 2021). ...
Microalgae-based wastewater treatment technology is a sustainable and environmentally friendly alternative to conventional treatment systems. The biomass produced during microalgae-based wastewater treatment can be valorized via pyrolysis to generate multiple valuable products, such as biochar, bio-oil, and pyrolytic gas. This study summarizes the potential of pyrolysis for valorizing microalgal biomass produced from wastewater treatment. It shows how pyrolysis can provide a variety of valuable products, the composition of which is influenced by the type of microalgae used, the operating conditions of the pyrolysis process, and the presence of contaminants in the biomass. It also highlights the main challenges to be addressed before pyrolysis can be adopted to valorize microalgae biomass. These challenges include the high energy requirements of pyrolysis, the need for further research to optimize the process, and the potential for pyrolysis to produce harmful emissions. Despite this, pyrolysis appears as a promising technology with potential to contribute to the sustainable development of a circular economy. Future research should address these challenges and develop more efficient and environmentally friendly pyrolysis processes.
Graphical abstract
... They can also catalyze dehydrocyclization, isomerization and aromatization. Thus, the net compositions will include substantial amount of aromatics (BTEX; benzene, toluene, ethylbenzenes and xylenes) and fuel range paraffins [97][98][99][100]. ...
The production of energy crops as biomass resources for conversion into different fuels is increasingly becoming an issue of industrial interest for establishing a balance between energy security and hunger threats. In line with this perspective, the present review discussed a comprehensive analysis of wide literature on the process commercialization potentials from the catalysis point of view. Concise details on the major energy crops were initially provided together with highlights on current industrial status. Specifically, catalytic fast pyrolysis (including the ablative method) of energy crops feed and derived bio-oil upgrading were discussed. Catalytic strategies suitable for the production of high heating value bio-oil that is rich in hydrocarbons (i.e. both BTEX aromatics and aliphatic) were highlighted. For the interest of commercial advances, the paper discussed the role of different catalytic systems including low-cost oxides, natural zeolites and the catalyst materials derived from industrial wastes such as red mud and steel slags. Perspective areas for further investigations were subsequently highlighted.
Graphical Abstract
... A longer residence time is typically required with less intense heat, and the byproducts of pyrolysis are typically tars (a mixture of aromatic hydrocarbons with a molecular weight 7 greater than benzene), gases, and char (Fakhrhoseini and Dastanian, 2013). Flue gas cleanup is unnecessary for pyrolysis because the released flue gas is frequently processed before use (Bridgwater, 2012). Additionally, it produces essential products for petrochemical and petroleum refining processes, which can jeopardise the dependability of petroleum processing (Heikkinen et al., 2004). ...
This research aimed to conduct a pyrolytic conversion of waste plastics using an African seed-based activated carbon catalyst. The process description to produce activated carbon from African star apple includes removing and drying seed husks, grinding, and preparing activated carbon (AC). The plastic waste materials used for the catalytic pyrolysis process were waste Low-Density Polyethylene (LDPE) and High-Density Polyethylene (HDPE) plastic, which were sourced from Liberation Stadium Road, GRA Phase IV, Port Harcourt, Rivers State. The effects of activated carbon (AC) as a catalyst on fuel production and gasification efficiency were also evaluated. Proximate and ultimate analyses were conducted on the AC to determine its composition. The results showed that the AC had high fixed carbon content and low volatile matter and ash contents. The experiments also showed that the products' density, calorific value, cetane number, and kinematic viscosity were within the range of diesel fuel specifications. However, the water, flashpoint, acid number, ash, and nitrogen content were higher than diesel fuel. The addition of AC catalyst improved the properties of the pyrolyzed products by reducing the water content, acid number, and ash content.
... Lignocellulosic biomass, such as forestry and agricultural residues, is a cost-effective alternative to obtain a wide range of carbonbased materials [1][2][3]. Pyrolysis stands out as one of the most promising alternatives to convert lignocellulose into valuable products due to its simplicity and versatility to admit different organic residues as feedstock [4,5]. During the pyrolysis process, the thermal decomposition of the lignocellulosic biopolymers (cellulose, hemicellulose, and lignin) occurs at temperatures ranging from 300 to 700 • C under an O 2 -free atmosphere, yielding three main products: a gaseous phase mainly composed by CO and CO 2 , a carbonaceous solid known as biochar and a liquid bio-oil, considered a precursor for biofuels and bio-based chemicals production [6,7]. ...
Lignocellulosic biomass pyrolysis has been earlier studied in a large variety of reaction systems. However, there is a lack of information on the effects of passing from batch to continuous feeding mode (BM vs CM) despite being a necessary step in the scaling up of the process. In this sense, the main aim of this work is to conduct a comparative study of lignocellulosic biomass pyrolysis using the same reactor but varying the biomass feeding methods under thermal and catalytic conditions and different thermal zone temperatures (350 and 500 °C). Under thermal conditions, significant differences have been observed between both feeding systems. When operating in CM, the production of char decreases, particularly at 500 °C, from 27.3 to 18.9 wt% while the generation of gases increases. This can be attributed to the differences in the feeding mode since the CM allows a higher biomass heating rate, resulting in a more efficient lignocellulose decomposition. On the other hand, the balance between the higher residence time and the lower concentration of the vapours reduces the occurrence of secondary charring reactions. Consequently, the share of water in the liquid fraction diminishes in CM, although only a notable increase of bio-oil* (bio-oil in water-free basis) is observed at 500 °C (39.9 vs 45.0 wt%). The bio oil* molecular composition is also modified by this shifting, leading to higher sugars and oxygenated aromatics in the CM reactor at 500 °C. The different operation modes also affect the interaction between the vapours and the catalyst when the n-ZSM-5 is introduced into the reactor. The vapours are more diluted in CM in comparison with the batch one, allowing a more progressive and efficient catalytic conversion. As a result, less coke is deposited over the zeolite catalyst leading to an enhanced production of aromatic hydrocarbons, achieving yields of ca. 7.6 wt%.
Pyrolysis is a thermochemical conversion process producing biochar, gas, and bio-oil at high temperatures in an oxygen-free environment. Specific pyrolysis conditions enable a significant production of the aqueous phase of bio-oil, commonly known as wood vinegar. Wood vinegar contains organic compounds such as acetic acid and phenols derived from bio-oil. These compounds have herbicidal properties against weeds and biostimulant properties for plant growth. This study reveals the potential for efficient management of cranberry residues consisting of stems and leaves by producing wood vinegar through pyrolysis at 475 °C with a humidity level of 20%. Membrane separation of wood vinegar, using nanofiltration (NF) and reverse osmosis (RO) membranes, yielded phenols in the retentate and acetic acid in the permeate with respective yields of 44.7% with NF membrane and 45% with RO membrane. Biostimulation tests using 2% of the retentate showed significant germination rates for basil, sage, and parsley plants. Additionally, using 40 mL of the wood vinegar permeate (30 mL injected at the base and 10 mL sprayed on the leaves) resulted in leaf damage, measured by conductivity (leakage of electrolytes released by the leaves), of 62.3% and 20.5% respectively for quack grass and white clover, two weeds found in cranberry production.
The pyrolysis of waste plastics is important because it offers a viable solution to mitigate environmental pollution by converting plastic waste into valuable resources, such as fuel, chemicals, and carbon materials. In this research, response surface optimization was performed to maximize wax yield through slow thermal pyrolysis of 5 kg waste high density polyethylene (HDPE). The slow pyrolysis was executed by varying heating rate (4 to 8 °C/min) and temperature (388 to 438 °C). A theoretical quadratic model was generated to optimize the wax yield and then validated through experiments. A maximum wax yield of 79.1% was achieved at heating rate and temperature of 7.9 °C/min and 434.3 °C, respectively. The wax thus collected was distilled to obtain 2.2 L pyrolysis oil and the properties were investigated. The characteristics of fuel were observed to be in-between those of petrol and diesel. Thus, HDPE could be a potential substrate to produce liquid transportation fuel by slow thermal pyrolysis.
The effect of water on the modification of acidic properties of Nb2O5 and Nb1.3MnOx catalysts was investigated using the cracking of cumene as model reaction, and compared to the behavior of a HZSM-5 catalyst. Nb1.3MnOx exhibited stronger Lewis acidity than Nb2O5, which translated into a higher selectivity towards α-methylstyrene formed on Lewis acid sites (LAS) by dehydrogenation of cumene. Steam enhanced strongly the conversion of cumene over both Nb-based catalysts. The products distribution on Nb-based catalysts was also deeply modified in the presence of steam, the selectivity towards α-methylstyrene decreasing strongly in favor of benzene, which is formed on Brønsted acid sites (BAS) by dealkylation of cumene. In contrast, the performances of HZSM-5 for cumene cracking and the products distribution were only marginally modified in the presence of steam. A kinetic model based on the elementary steps of the cumene reaction pathways (dealkylation and dehydrogenation) was used to estimate the ratio of LAS to BAS in absence and presence of water over Nb1.3MnOx. The activation energy of the cracking reaction was higher than that of the dehydrogenation reaction. The model described correctly the changes in the catalyst activity induced by addition of ≈2 V% of water, which resulted in a decrease in the [LAS]/[BAS] ratio from approximatively 3 to 1.
The agri-food industry creates a vast amount of waste each year. This is not just a problem for waste management, in terms of finding space to store waste and preventing escape of harmful waste into the environment; it also represents a loss of resources: the chemicals and energy which have gone into the production of this waste. If current waste streams can be converted into useful resources this will have multiple benefits by reducing the amount of waste sent to landfill or similar, reducing the need for other feedstocks and removing the pressure from feedstocks that could be used as food.
Research into the different types of waste produced by the agri-food industry and approaches to converting them into useful chemicals or chemical feedstocks has advanced rapidly over the last few years. Covering the latest developments in the valorisation of food and agricultural waste, such as valorisation of citrus peel and industrial wastes, this book is a great resource for researchers interested in waste management, sustainability and the circular economy.
The rapid growth of global industrialization and urbanization has led to the excessive use of non-renewable energy sources and the alarming release of greenhouse gases within the construction industry. In response, adopting sustainable and environmentally friendly building materials has emerged as a vital solution for achieving the international sustainable development goals set by the United Nations. This review discusses the potential benefits of incorporating biochar-based bricks and insulation materials, focusing on their preparation methods, material properties, emission reduction capabilities, effectiveness in reducing carbon emissions, enhancing thermal insulation, and promising economic prospects. The major points are: (1) Biochar-based materials offer significant potential for reducing the carbon footprint of buildings and enhancing their thermal insulation properties. (2) With a thermal conductivity ranging from 0.08 to 0.2 W/(m·K), biochar insulation materials contribute to reduced energy consumption and greenhouse gas emissions. (3) Replacing one ton of cement with biochar in brick production can substantially reduce 1351–1505 kg CO2-eq over the entire life cycle. (4) Using biochar as part of concrete insulation saves about 59–65 kg of carbon dioxide per ton while offering clear economic benefits. Although biochar insulation is comparatively more expensive than traditional insulation materials like fiberglass and foam, its energy-saving advantages can balance the extra cost. (5) Biochar insulation is derived from organic waste, contributing to improved recyclability, environmental sustainability, and cost-effectiveness.
Pyrolysis of agricultural biomass to produce bio-oil and biochar is a sustainable route for energy and fuel production. The rice husk (RH) is a major agricultural residue produced in larger amounts in India. In this study, lab-scale pyrolysis of RH was performed to evaluate the type of products and their composition at different temperatures (200–400 °C) in a batch reactor. Furthermore, RH was characterized to understand its physical as well as chemical properties thoroughly via various methods, for instance, proximate analysis, ultimate analysis, calorific value analysis, and thermogravimetric analysis (TGA). Along with this, the effect of pyrolysis temperature on the yields of products and the composition of bio-oil was also investigated. The experimental results revealed that the maximum bio-oil yield of 33.4 wt.% was obtained at 400 °C. Acid pre-treatment using hydrochloric acid (HCl) was also done to remove the impurities like Alkali and Alkaline Earth Metals (AAEMs) present in the RH. The pre-treatment was found to increase the yield of bio-oil to 37.3 wt.% and reduce the yield of biochar and gases by 2.1 wt.% and 1.8 wt.%, respectively. Gas Chromatography−Mass Spectroscopy (GC−MS) and Fourier Transform−Infrared (FT−IR) analysis were used to identify the chemical composition and functional groups present in the bio-oil obtained at various temperatures. A complex combination of acids, alcohols, furans, ketones, phenols, sugars, and other compounds was discovered in the bio-oil.
This volume is a comprehensive compilation of reviews that show how various waste products can be used to produce useful products. Thirteen chapters highlight the following topics:
- applications of plant-derived and fruit waste for value-added product formation;
- fuel and chemical production from lignin
- food waste bioconversion to high-value products
- organic residues valorization for value-added chemicals
- valorization of waste plastics to produce fuels and chemicals
- food valorization for bioplastic production and concepts of circular economy in the valorization process.
Chapters are written in an organized and strategic manner and also include the references from recent years. It will help students and researchers to quickly learn about modern waste valorization practices and advance their knowledge on the subject. The book is suitable as a reference for courses in environmental science, chemical engineering and agriculture. It also serves as a guide for trainees, managers and readers involved in waste management, sustainability and value-added product supply chains
This comprehensive review explores recent catalyst advancements for the hydrodeoxygenation (HDO) of aromatic oxygenates derived from lignin, with a specific focus on the selective production of valuable aromatics under moderate reaction conditions. It addresses critical challenges in bio-crude oil upgrading, encompassing issues related to catalyst deactivation from coking, methods to mitigate deactivation, and techniques for catalyst regeneration. The study investigates various oxygenates found in bio-crude oil, such as phenol, guaiacol, anisole, and catechol, elucidating their conversion pathways during HDO. The review emphasizes the paramount importance of selectively generating arenes by directly cleaving C–O bonds while avoiding unwanted ring hydrogenation pathways. A comparative analysis of different bio-crude oil upgrading processes underscores the need to enhance biofuel quality for practical applications. Additionally, the review focuses on catalyst design for HDO. It compares six major catalyst categories, including metal sulfides, transition metals, metal phosphides, nitrides, carbides, and oxides, to provide insights for efficient bio-crude oil upgrading toward sustainable and eco-friendly energy alternatives.
The present study reports on an investigation of teak sawdust pyrolysis oil blended with commercial diesel in a small four-stroke compression ignited engine. The engine performance and emissions were evaluated. The teak sawdust pyrolysis oil was obtained from a single-stage fixed bed pyrolysis reactor at 600 °C. Its physicochemical properties were characterized and found to be acceptable for the engine. Teak sawdust pyrolysis oil blends with diesel at the ratios of 10%, 25%, and 50% by mass were utilized. The small engine was tested at constant speeds from 800 to 2600 r/min. 25% teak sawdust pyrolysis oil blend at 2000 r/min was found to have better brake thermal efficiency with lower brake-specific fuel consumption compared to the other teak sawdust pyrolysis oil blends. Meanwhile, the highest engine load was obtained at 50% teak sawdust pyrolysis oil blend and 2600 r/min to be 8 kW. Furthermore, the emissions of CO, CO 2 , and hydrocarbon at 50% teak sawdust pyrolysis oil and 2000 r/min were slightly lower than other teak sawdust pyrolysis oil blends, no NO x detection in tested fuels, moreover, at 2600 speed, the smoke opacities of the fuels show lower than those the others. It was noted that a blend of 25% teak sawdust pyrolysis oil with diesel was suitable for the small engine (at 2000 r/min) in terms of performance and CO, CO 2 , and NO X emission for sustainability in agriculture and rural areas.
Fossil fuels are the main energy sources worldwide even today. But with the alarming pace at which fossil fuels are exhausting, there would be a need for sustainable and economically viable alternatives in the near future. Fossil fuels pose severe environmental threats like air pollution, soil pollution, global warming etc. It is reported that the utilization of algal biomass to produce bioenergy could be one of the solutions. Microalgae offer many unique features with the potential to store lipids in their cells just like plant oils, CO2 sequestering capability, low space requirement, rapid growth, ability to grow in wastewater and rich in lipid and carbohydrate content. Although an array of nutrients is required for an algal bloom that could be fulfilled by nutrients from wastewater. In a way, it is the biological wastewater treatment technology producing green energy (WtE). Methods like supercritical fluid extraction, microwave and ultrasonic-assisted extraction, and Soxhlet extraction could be used for the microalgal lipid extraction. So, this chapter explores the possible methods to isolate lipids from biomass and their energy utilization.
Transportation currently takes up around a third of overall energy usage, of which the majority is petroleum-based gasoline. Petroleum is both a finite resource and a big contributor to the carbon emissions that are causing climate change. To continue to benefit from transportation whilst mitigating climate change it is essential to find alternatives to petroleum-based gasoline. Although a lot of recent developments have focused on electrifying transport the infrastructure for large scale uptake of electric vehicles is still lacking and it may be less practical in some parts of the world than others. Biofuels, therefore, still have a role to play in improving the sustainability of our transportation systems.
The term green gasoline refers to biofuels intended to be direct drop-in replacements for petroleum-based gasoline. Such products allow vehicles to run on biofuel without any engine modifications and, being made from biomass, they are both renewable and have a better carbon emission profile than petroleum-based gasoline.
Green Gasoline covers a range of new technologies being used to produce these biofuels and compares them to petroleum-based fuels in terms of sustainability. It will be an interesting read for those working in fuel chemistry as well as green chemists and anyone with an interest in transport sustainability.
Biomass-based solutions have been discussed as having the potential to replace fossil-based solutions in the iron and steel industry. To produce the biocarbon required in these processes, thermochemical treatment, pyrolysis, typically takes place. There are various ways to produce biocarbon, alongside other products, which are called pyrolysis oil and pyrolysis gas. These conversion methods can be divided into conventional and non-conventional methods. In this paper, those techniques and technologies to produce biocarbon are summarized and reviewed. Additionally, the effect of different process parameters and their effect on biocarbon yield and properties are summarized. The process parameters considered were final pyrolysis temperature, heating rate, reaction atmosphere, pressure, catalyst, use of binders, and particle size. Finally, the effect of different reactor configurations is discussed. Understanding the combination of these methods, technology parameters, and reactor configurations will help to produce biocarbon with the desired quality and highest yield possible.
The use of hydrolyzed rice straw (HRS) and hydrolyzed rice husk (HRH) as feedstock for pyrolysis was evaluated through kinetic and thermodynamic studies. HRS and HRH were obtained from subcritical water hydrolysis (SWH) at different temperatures (180, 220, and 260°C). The Coats‐Redfern method was used to analyze the thermal behavior through thermogravimetry (TG) and derivative thermogravimetry (DTG) curves. TG profiles showed higher decomposition in the range of 250–400°C, especially for rice straw (RS) and HRS (80 wt %). The pyrolysis curves were well predicted by a first‐order reaction model. The kinetic analysis showed a variation in activation energy ( E A ) between 24.3 to 41.3 kJ mol ⁻¹ and 40.4 to 54.7 kJ mol ⁻¹ for RS/HRS and rice husk (RH)/HRH, respectively. The enthalpy (Δ H ), Gibbs free energy (Δ G ), and entropy (Δ S ) varied from 25.9 to 39.6 kJ mol ⁻¹ , 35.4 to 69.6 kJ mol ⁻¹ , and −64.1 to −6.7 J mol ⁻¹ K ⁻¹ , respectively, for RS/HRS, and 35 to 49.8 kJ mol ⁻¹ , 43.2 to 79.3 kJ mol ⁻¹ , and −53.5 to −10.2 J mol ⁻¹ K ⁻¹ , respectively, for RH/HRH. These results showed that the pyrolysis reactivity using HRS is higher than HRH, which indicates the pyrolysis of HRS is more advantageous than HRH.
In this study, a sealable fixed‐bed reactor was developed to investigate the influence of gaseous products on lignin pyrolysis with a strategy of hydrogen self‐supply, and lignin pyrolysis performances at various temperatures were monitored by the comprehensive characterization of the generated products, including gas, bio‐oil and char. The results showed that the release of volatiles (both gas and bio‐oil) from lignin was strengthened in this sealable system when the temperature rose, and therefore less char was left. Meanwhile no H 2 was detected under any of the operating conditions, which is a common component in pyrolysis gas from conventional reactors, indicating its participation in lignin pyrolysis. Furthermore, the formation of CO and CO 2 in the employed pyrolyzer benefited from not only the thermal evolution of feedstock, but also the interactions between char residues and generated gas components. Meanwhile, because of the hydrogen self‐supply, compounds in bio‐oil were enriched and only nine species were detected, which were all phenolic compounds. Vanillic acid was dominant, and its relative content was up to 38.86% for Alcell organosolv lignin and 34.41% for soda alkali lignin. This illustrates that highly selective production of phenolic compounds from lignin pyrolysis can be achieved by self‐supplying hydrogen from pyrolysis gas.
Este estudo investigou a viabilidade da utilização do bagaço de malte, um resíduo agroindustrial da indústria cervejeira, como fonte alternativa de energia por meio da pirólise. Foi realizada uma análise das condições de calcinação da dolomita, um mineral composto por carbonato de magnésio e cálcio, visando sua aplicação como catalisador na pirólise do bagaço de malte. Através da técnica de micropirólise, foram avaliados os vapores pirolíticos para aprimorar a qualidade do bio-óleo resultante, removendo compostos oxigenados indesejáveis. Os resultados revelaram variações significativas nos rendimentos de hidrocarbonetos conforme as diferentes condições de calcinação da dolomita. O catalisador calcinado a 950°C apresentou o maior rendimento de hidrocarbonetos e maior desoxigenação parcial, demonstrando seu potencial para aprimorar a eficiência da pirólise e a qualidade do bio-óleo. A pesquisa destaca a importância da otimização das condições de calcinação e a relevância dos catalisadores não metálicos na conversão de biomassa em recursos energéticos sustentáveis.
Biomass fast pyrolysis liquid is being developed for fuel and chemical applications. As these developments proceed, the liquid product is increasingly being transported by air, water, rail and road to satisfy user demands for products. This paper addresses the legislative requirements and regulations for the safe transport of this liquid. As biomass derived fast pyrolysis liquid is not on the UN approved carriage lists; its own classification has been determined from the UN manual as:
UN 1993 Flammable Liquid [Fast Pyrolysis Liquid], n.o.s., 3, 1º(a), 2º(a), 1
This classification should be used on all packages containing biomass fast pyrolysis liquid. Protocols for the labelling of packages and containers of all sizes are given with the aim of compliance with transport regulations in the EU, Canada and the USA. In conjunction with the requirements for packaging and labelling, guidance on the details to be enclosed on the transportation documents are given, with appropriate MSDS for the liquids. Guidance on the handling of fast pyrolysis liquid and its storage are given with procedures for treatment of spills.
The disclosure encompasses in-line reactive condensation processes via vapor phase esterification of bio-oil to decease reactive species concentration and water content in the oily phase of a two-phase oil, thereby increasing storage stability and heating value. Esterification of the bio-oil vapor occurs via the vapor phase contact and subsequent reaction of organic acids with ethanol during condensation results in the production of water and esters. The pyrolysis oil product can have an increased ester content and an increased stability when compared to a condensed pyrolysis oil product not treated with an atomized alcohol.
This publication is an updated version of a study on testing and modifying standard fuel oil analyses (Oasmaa et al. 1997, Oasmaa & Peacocke 2001). Additional data have been included to address the wide spectrum of properties that may be required in different applications and to assist in the design of process equipment and power generation systems. In addition, information on specifications and registration is provided. Physical property data on a range of pyrolysis liquids from published sources have been added to provide a more comprehensive guide for users.
There is increasing recognition that low-cost, high capacity processes for the conversion of biomass into fuels and chemicals are essential for expanding the utilization of carbon neutral processes, reducing dependency on fossil fuel resources, and increasing rural income. While much attention has focused on the use of biomass to produce ethanol via fermentation, high capacity processes are also required for the production of hydrocarbon fuels and chemicals from lignocellulosic biomass. In this context, this book provides an up-to-date overview of the thermochemical methods available for biomass conversion to liquid fuels and chemicals. In addition to traditional conversion technologies such as fast pyrolysis, new developments are considered, including catalytic routes for the production of liquid fuels from carbohydrates and the use of ionic liquids for lignocellulose utilization. The individual chapters, written by experts in the field, provide an introduction to each topic, as well as describing recent research developments.
Bio-oils produced from fast pyrolysis of biomass are chemically complex compounds. As fuels they have a number of negative properties such as high acidity, water content, variable viscosity and heating values about half that of petroleum fuel. These negative properties are related to the oxygenated compounds contained in bio-oils that result in a 45% oxygen content. For production of a viable fuel the raw bio-oils must be upgraded. The bio-oil hydrotreating process has been approached by applying hydrogenation catalysts under heat and pressure. Researchers have reported application of a successful two-stage catalytic hydrodeoxygenation (HDO) process. We have recently developed a two-stage HDO catalysis as well. The upgraded bio-oil contains hydrocarbons very similar to petroleum fuels. Yields of the upgraded bio-oils are more than 70% by energy capture. Future research on the upgraded product will focus on distillation and introduction into petroleum refineries and investigating the potential for direct blending with current petroleum fuels.
Experimental results and a process design will be presented for an integrated process which uses hydropyrolysis plus hydroconversion to convert biomass into gasoline and diesel. The hydrogen needed for the hydropyrolysis and hydroconversion process is produced by reforming the light gases so that no external H2 is required. Finished hydrocarbon products with less than 2% oxygen are produced using this processing approach.
This design solves many of the problems associated with pyrolysis and subsequent upgrading. By having an integrated process, a fungible finished product is produced which has the oxygen removed and is ready for use. This eliminates the need for transporting high TAN, unstable, low BTU content pyrolysis oils. An integrated process also eliminates the problems associated with upgrading pyrolysis oils which were created in a hydrogen starved environment and therefore include high olefinic, polynuclear aromatics and free radicals which were not present in the original biomass. Pyrolysis oils require high pressure to convert because of the condensed ring aromatic structures present. Hydropyrolysis oils can be converted at moderate pressure. The initial hydropyrolysis step is done at moderate pressure and then feeds directly into the hydroconversion step run at almost the same pressure. The light gases from the hydroconversion then go to a small steam reformer where the H2 is made and the CO2 rejected. The H2 produced is recycled back to the hydropyrolysis step.
Initial data which shows the yields and product properties from experiments in pilot scale equipment will be presented and compared to results for traditional pyrolysis. Some economic analysis will also be done to show the advantages of integrated balanced hydropyrolysis + hydroconversion compared to traditional approaches.
In order to gain insight into the fast pyrolysis mechanism of biomass and the relationship between bio-oil composition and pyrolysis reaction conditions, to assess the possibility for the raw bio-oil to be used as fuel, and to evaluate the concept of spout-fluidized bed reactor as the reactor for fast pyrolysis of biomass to prepare fuel oil, the composition and combustion characteristics of bio-oil prepared in a spout-fluidized bed reactor with a designed maximum capacity 5 kg/h of sawdust as feeding material, were investigated by GC-MS and thermogravimetry. 14 aromatic series chemicals were identified. The thermogravimetric analysis indicated that the bio-oil was liable to combustion, the combustion temperature increased with the heating rate, and only minute ash was generated when it burned. The kinetics of the combustion reaction was studied and the kinetic parameters were calculated by both Ozawa-Flynn-Wall and Popsecu methods. The results agree well with each other. The most probable combustion mechanism functions determined by Popescu method are f(a)=k(1-a)2 (400-406°C), f(a)=1/2k(1-a)3 (406-416°C) and f(a)=2k(1-a)3/2 (416-430°C) respectively.
This book is for chemical engineers, fuel technologists, agricultural engineers and chemists in the world-wide energy industry and in academic, research and government institutions. It provides a thorough review of, and entry to, the primary and review literature surrounding the subject. The authors are internationally recognised experts in their field and combine to provide both commercial relevance and academic rigour. Contributions are based on papers delivered to the Fifth International Conference sponsored by the IEA Bioenergy Agreement.
IntroductionMaterials and Methods
ResultsMaximis Ation Function of CarbonizationPyrolytic Carbon DepositionConclusion
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IntroductionMaterials and Methods
Results and DiscussionConclusion
AcknowledgmentReferences
IntroductionExperimentalResults and DiscussionConclusion
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IntroductionExperimentalResults and DiscussionConclusions
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IntroductionRating Index (RI)Step Wise Procedure to Calculate Rating IndicesBiomass Characterisation Based on NriConclusions
References
Hydrogen was prepared via catalytic steam reforming of bio-oil which was obtained from fast pyrolysis of biomass in a fluidized bed reactor. Influential factors including temperature, weight hourly space velocity (WHSV) of bio-oil, mass ratio of steam to bio-oil (S/B) as well as catalyst type on hydrogen selectivity and other desirable gas products were investigated. Based on hydrogen in stoichiometric potential and carbon balance in gaseous phase and feed, hydrogen yield and carbon selectivity were examined. The experimental results show that higher temperature favors the hydrogen selectivity by H2 mole fraction in gaseous products stream and it plays an important role in hydrogen yield and carbon selectivity. Higher hydrogen selectivity and yield, and carbon selectivity were obtained at lower bio-oil WHSV. In catalytic steam reforming system a maximum steam concentration value exists, at which hydrogen selectivity and yield, and carbon selectivity keep constant. Through experiments, preferential operation conditions were obtained as follows: temperature 800-850°C, bio-oil WHSV below 3.0 h-1, and mass ratio of steam to bio-oil 10-12. The performance tests indicate that Ni-based catalysts are optional, especially Ni/a-Al2O3 effective in the steam reforming process.
Fractional catalytic pyrolysis is a process selectively targeting individual biopolymer components of the biomass to produce specific product slates. This method was used to screen several biomass feedstocks (switchgrass, corn stover, pinewood, hybrid poplar wood, oakwood) for adhesives production. Pyrolysis experiments were conducted at 400 to 450 °C and pyrolysis oil yields ranged from 30-50 wt%. The oils had very low molecular weight, low viscosity and pH of 3-4. The oils were used as substitutes for phenol in phenol /formaldehyde reactions. Both Novolac and Resol resins were prepared from the oils. For these reactions, there was no need for any pretreatments such as extractions, filtrations or neutralization (they were used as received). Excellent polymerization results were obtained and up to 95 wt% of the phenol could be replaced by the oils. The results were similar for all feedstocks except switchgrass oils which did not form good resins. All the oils were rich in both hydrocarbons and phenolics. However, the switchgrass oil had the highest hydrocarbon fraction.
Within the framework of the applied research carried out by ENEL, aimed at utilising non-traditional fuels derived from the renewable resources of the territory, the Thermal Research Centre of Pisa has realized a R&D plant for bio-oil production, through a flash pyrolysis process of vegetable biomass. The Project, that is being carried out in close collaboration with the Umbria Region, is partially financed by EU. The plant has been erected at the ENEL thermoelectric power plant of Bastardo (Perugia). The process unit (RTP-Rapid Thermal Processing) has been developed by the Canadian Ensyn Company, whereas ENEL has designed and constructed the auxiliary facilities. The plant, with a capacity of processing 15 tonnes/day of dry feedstock and capable of producing around 10 tonnes/day of liquid fuel, is the largest plant of this type in Europe. The paper describes the technical characteristics of the plant and the aims of the tests that will be performed with hardwood sawdust and other sorts of feedstocks. The tests are finalized to assess the technical-economic fesibility of the flash-pyrolysis process, a step necessary for the commercialisation of the technology.
Many plant materials contain minor amounts, often only in the 100 ppm range, of complex compounds which may have a considerable present or potential application in biological or pharmaceutical areas. Extraction and concentration of these specialty chemicals by conventional technology can be a laborious and costly process.
Examples are given in which fast fluid bed pyrolysis has been used in our research to obtain pyrolysis liquids considerably enriched in such compounds, even when they have very low volatilities. One example involves the recovery of an alkaloid from plant leaves. Another feedstock gives complex terpene-based compounds (taxanes) which can be precursors for synthesis of new antitumor agents, or that can be used as a potential plant fungicide. Additional examples of complex compounds obtained in significant yields in fast pyrolysis oils can be found in the high molecular weight lignin fragments, largely aromatic in character, which are a part of the “pyrolytic lignin” fraction of a pyrolysis oil; and in the anhydrosugar monomers, dimers and oligomers obtained from the carbohydrate fraction of biomass on fast pyrolysis.
Some unique features, and some speculations on mechanisms, of such specialized pyrolytic processes are discussed.
This paper presents the results obtained during the commissioning and first series of experiments of the EGEMIN entrained bed flash pyrolysis process. The feedstock used was as-received wood waste and at an average reactor temperature of about 510 °C. A bio-oil yield of 40% was obtained on a moisture-free basis. The charcoal and gas yields were 29 and 16% respectively while the balance was water. Elemental analysis of the products indicates the incomplete conversion of the char as well as a relatively high oxygen content in the bio-oil.
IntroductionExpefumentalResults And DiscussionAcknowledgementReferences
IntroductionTechnical ApproachExperimentalResultsConclusions
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This paper presents the results obtained in the characterization of two different pyrolysis oils, the first one produced by carbonization and the second by flash pyrolysis. Chemical and physical properties such as density, viscosity, elemental composition, char content, water content, solubility and heating value were first determined, then an in-depth chemical characterization was carried out by liquid-liquid fractionation. We present a diagram indicating the separation procedure to provide four fractions (acids, bases, polars and hydrocarbons). We also recuperated very polar molecules which were retained in the aqueous layer (“aqueous” fraction). Each fraction was subsequently analyzed by GC-MS and FTIR.
The acidic fraction is the most abundant and contains essentially phenolic structure, nevertheless phenols are differently substituted in the two oils: alkyl and methoxy groups in the carbonization oil, methoxy, acidic, aldehydic and ketonic functions in the flash pyrolysis oil. The other fractions present a similar composition for the two oils. Basic fraction is always very small, some aromaticN-containing compounds were identified. The “polar” neutral fraction is also small and its characterization is very difficult. The hydrocarbon fraction is especially constituted of aromatics and cyclics, some aliphatics were also identified. The “aqueous” fraction contains mainly carboxylic esters, alcohols and ethers.
Highly oxygenated, biomass-derived oils can be upgraded to high quality hydrocarbon fuels by catalytic hydrotreating. Pacific Northwest Laboratory has successfully converted both high-pressure liquefaction oils and low-pressure pyrolysis oils to a highly aromatic, gasoline boiling range fuel. These studies were conducted in a 1-liter, continuous-flow reactor system. Six different biomass-derived oils and one peat-derived oil have been tested.
A handicap facing both the producer and the user of fast-pyrolysis oils is the lack of a description of these oils that is adequate for commercial applications. These oils are highly oxygenated and are relatively immiscible with petroleum oils. Under the current IEA Biomass Energy Agreement, the new Pyrolysis Activity (PYRA) has taken on the task of establishing a useful description of a series of pyrolysis oils. This series roughly parallels that of petroleum fuel oils already described, so that with as few changes as possible to the users’ equipment, a bio-oil could be used in place of the equivalent petroleum-derived oil. The specifications for biomass pyrolysis oils differ in the density, heating value, water content, and corrosiveness. These proposed specifications are presented for discussion by the biomass conversion community and feedback to the Pyrolysis Activity.
The Liquefaction Group of the lEA Biomass Agreement has carefully studied and analyzed a thermochemical conversion process under development at the National Renewable Energy Laboratory (NREL, formerly the Solar Energy Research Institute). This process converts biomass to an aromatic gasoline product. Biomass is subjected to very rapid pyrolysis in a vortex reactor to maximize the formation of oil vapors. After the char is removed from the process stream, the oil vapors are immediately sent to a catalytic cracking reactor with ZSM-5 zeolite catalyst to form a mixture of aromatic gasoline and gaseous olefins. Subsequent processing recovers byproduct gaseous olefms and converts them to aromatic gasoline. The small amount of toxic benzene formed as an intermediate compound is alkylated to extinction to form relatively benign compounds with a higher octane, such as cumene. The narrow boiling range desired for tomorrow’s reformulated gasolines is maintained by recycling both the volatile light ends and the difficult-to-bum heavy ends to extinction. A gasoline with a very high blending octane is the primary product. It is expected that this product will command a premium price. The process features state-of-the-art energy-saving and waste-management techniques. Using a consistent and well documented approach, the technoeconomics of this process were determined for both a “present” case and a “potential” case. The difference between the product costs for these two cases serves as an incentive for further research and development (R&D).
The bio-oil obtained from the fast pyrolysis of biomass has a high oxygen content. Ketones and aldehydes, carboxylic acids and esters, aliphatic and aromatic alcohols, and ethers have been detected in significant quantities. Because of the reactivity of oxygenated groups, the main problems of the oil are instability. Therefore study of the deoxygenation of bio-oil is needed. In the present work the mechanism of hydrodeoxygenation (HDO) of bio-oil in the presence of a cobalt molybdate catalyst was studied. Particularly, the effects of reaction time, temperature, and hydrogen pressure on the HDO activity were examined. On the experimental results, a kinetic model for HDO of bio-oil was proposed.
In the context of alternative sources of energy, many routes have been explored for using biomass. Direct combustion remains the most energy efficient use of biomass but liquids, rather than solids or gases, are preferred. Liquids have many advantages: high energy density, easy storage, handling and transportation and flexibility of use. Nevertheless, these liquids present some unwanted characteristics such as high viscosity, acidity, particulates content and chemical instability. Some upgrading is necessary before utilisation, specially for feeding turbines or internal combustion engines. Three different types of upgrading can be envisioned: physical, chemical/catalytic and the recovery of chemicals. Physical methods such as those to improve viscosity, offer potentially low cost steps which can be applied when the oil is used as soon as produced. The more expensive chemical/catalytic processes offer long term stabilisation and a range of improvement extending to high quality products. This paper reviews the main characteristics of the flash pyrolysis oils, their influence during the utilisation step and the possible solution to overcome this situation. The most important upgrading methods, both physical and chemical/catalytic, are summarised.
Preliminary experimentation passing fresh softwood pyrolysis vapors over a ZSM-5 containing catalyst has shown promise for the production of a gasoline consisting primarily of high octane, methylated benzenes. Stoichiometric considerations show that the upper limit on the gasoline yield is about 63 gallons per ton of dry feedstock, if the coke by-product yield is only 5% and the phenolic by-product yield is only 3%. This gasoline yield would represent 48% of the energy in the biomass feedstock.
In the reported experiments, a continuous fluidized bed bench scale flash pyrolysis unit operating at atmospheric pressure and feed rates of about 15 g/h has been successfully designed and operated. A unique solids feeder capable of delivering constant low rates of biomass has been developed. Extensive pyrolysis tests with hybrid aspen-poplar sawdust (105-250 mu m) have been carried out to investigate the effects of temperature, particle size, pyrolysis atmosphere and wood pretreatment on yields of tar, organic liquids, gases and char. At optimum pyrolysis conditions high tar yields of up to 65% of the dry wood weight fuel are possible at residence times of less than one second. Refs.
IntroductionMaterials and Methods
Results and DiscussionConclusions
References
The theoretical yield of charcoal from biomass lies in the range 50-80% on a dry weight basis. In spite of the fact that mankind has been manufacturing charcoal for about 6000 years, traditional methods for charcoal production in developing countries realize yields of 20% or less, and modern industrial technology offers yields of only 25-37%. Moreover, reaction times for the batch process in an industrial kiln are typically 8 days. In this article we describe a practical method for manufacturing high-quality charcoal from biomass that realizes near-theoretical yields of 42-62% with a reaction time of about 15 min to 2 h, depending on the moisture content of the feed. Because of its high efficiency, this technology can help to reduce worldwide deforestation and pollution, while providing greater amounts of a desirable, renewable fuel and chemical resource to mankind.
The conversion of biomass into bio-oil using fast pyrolysis technology is one of the most promising alternatives to convert biomass into liquid products. However, substituting bio-oil for conventional petroleum fuels directly may be problematic because of the high viscosity, high oxygen content, and strong thermal instability of bio-oil. The focus of the current research is decreasing the oxygen and polymerization precursor content of the obtained bio-oil to improve its thermal stability and heating value. Catalytic fast pyrolysis of corncob with different percentages (5, 10, 20, and 30% by volume) of fresh fluidized catalytic cracking (FCC) catalyst (FC) and spent FCC catalyst (SC) in bed materials was conducted in a fluidized bed. The effects of the catalysts on the pyrolysis product yields and chemical composition of the bio-oil were investigated. A greater catalyst percentage lead to a lower bio-oil yield, while a lower catalyst percentage lead to little change of the composition of the bio-oil. The best percentages of FC and SC were 10 and 20%, respectively. FC showed more catalytic activation in converting oxygen into CO, CO2, and H2O than SC, but the oil fraction yield with FC was remarkably lower than that with SC because of more coke formation. The gas chromatography/mass spectrometry (GC/MS) analysis of the collected liquid in the second condenser showed that the most likely polymerization precursors, such as 2-methoxy-phenol, 2-methoxy-4-methyl-phenol, 4-ethyl-2-methoxy-phenol, 2-methoxy-4-vinylphenol, and 2,6-dimethoxy-phenol decreased, while monofunctional phenols, ketones, and furans increased compared to that in the noncatalytic experiment. The hydrocarbons increased with the increase of the catalyst percentages, and this contributed to the decrease of the oxygen content of the bio-oil. Multi-stage condensation achieved a good separation of the oil fraction and water.
Economical utilization of renewable energy sources is one of the viable solutions to reducing our dependency on fossil-based energy. Biomass is the only renewable energy source that can provide liquid fuels. In general, liquid fuels are obtained from biomass using either thermochemical or biochemical conversion method. Fast pyrolysis, a thermochemical process, is getting a lot of attention because all the three products (char, bio-oil and gas) have high potential as biomass energy feedstocks. Fast pyrolysis is a high temperature process in which biomass is thermally cracked into smaller compounds in an inert atmosphere at high heating rate. The vapor from this process is quickly condensed to liquid, which is called pyrolysis oil or bio-oil. The favorable conditions for maximum yield of oil are in the range of 400-600 oC and residence time of a few seconds and particle size less than 2 mm. Bio-oil is a chemically complex mixture of more than 300 compounds. Heating value of bio-oil is comparable with the heating value of other conventional liquid fuels evidence that it can be used as a transportation fuel. The possible utilization of bio-oil are however limited because of some negative attributes such as low pH, low heating value, high oxygen content, and high viscosity.
Gravity can be used to separate bio-oil into two phases - top aqueous phase and lower viscous tar phase. The aqueous phase contains mainly water and carbohydrates and the tar phase contains primarily lignin derived compounds. An aqueous phase reforming (APR) is a process in which hydrogen is produced from carbohydrate solutions. The uniqueness of the APR is that the reforming occurs at liquid state without volatilizing water. Hence, the energy requirement for the APR is lesser than the conventional steam reforming. In addition, the APR occurs at a low temperature and high pressure (200-300 oC and 10-90 bar) which favors water-gas shift reaction. There are a number of physical and chemical techniques to upgrade tar portion of bio-oil to a high quality fuel such as emulsification, solvent addition, hydro treatment and catalytic cracking. Hydrodeoxygenation (HDO) is one of the promising techniques for bio-oil to improve its heating content. The HDO is a process in which high pressure hydrogen is added into bio-oil in the presence of catalyst. Hydrogen reacts with oxygenated components to produce hydrocarbons and water. The operating conditions of HDO are around 250-450 oC and 150 bar. This study will explore the possibility of simultaneous reforming and hydrodeoxygenation of bio-oil.
Since the composition of bio-oil will be different for different feedstocks, four types of feedstocks have been selected for bio-oil production. The study of simultaneous APR and HDO of bio-oil will be carried out at different temperature, pressure and different types of catalyst. The challenging part for this study is the selection of the best catalyst which favors both the reactions with high conversion and stability. Effect of pressure, temperature and residence time on the quality of bio-oil over different catalysts will be reported. The best catalyst will be selected and the operating parameters will be optimized. This study will be carried out in a high pressure batch reactor. The chemical and physical analysis of bio-oil will be quantified before and after the reaction. Product gas analysis also will be carried out using GC coupled with thermal conductivity detector.