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The continuous flash pyrolysis of biomass

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Abstract

A continuous atmospheric pressure flash pyrolysis process for the production of organic liquids from cellulosic biomass has been demonstrated at a scale of 1–3 kg/hr of dry feed. Organic liquid yields as high as 65–70% of the dry feed can be obtained from hardwood waste material, and 45–50% from wheat straw. The fluidized sand bed pyrolysis reactor operates on a unique principle so that char does not accumulate in the bed and treatment of the sand is not necessary. The product gas, about 15% of the yield, has a medium heating value. The liquid product is an acidic fluid, which pours easily and appears to be stable. A preliminary economic analysis suggests that if the pyrolysis oil can be used directly as a fuel, its production cost from wood waste is probably competitive with conventional fuel oil at the present time. On a fait la démonstration d'un procédé continu de pyrolyse éclair à l'échelle de l à 3 kg/h d'alimentation sèche, à la pression atmosphérique, pour la production de liquides organiques à partir d'une biomasse cellulosique. On peut obtenir des rendements en liquide atteignant 65 à 70% de l'alimentation sèche à partir de déchets de bois dur et de 45 à 50% à partir de paille de blé. Le réacteur de pyrolyse, à lit de sable fluidisé, fonctionne sur un principe unique, de sorte que le charbon ne s'accumule pas dans le lit et qu'il n'est pas nécessaire de traiter le sable. Le produit gazeux, qui correspond à environ 15% de rendement, a une valeur calorifique moyenne. Le produit liquide est un fluide acide qui se déverse facilement et semble assez stable. Une analyse économique préliminaire indique que, si l'on peut employer directement l'huile de pyrolyse comme combustible, son coǔt de production à partir de déchets de bois est probablement compétitif actuellement avec celui de l'huile combustible classique.

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... A large variety of reactor types for fast pyrolysis has been investigated mainly at laboratory and pilot scale: ablative reactors in which the feedstock is heated by contact with a hot surface [54,56,63] like cyclone reactors [64][65][66][67][68], vortex reactors [54,[69][70][71][72], auger or double screw reactors [56,73,74], rotating cones, rotary kilns, and hearth furnaces [75][76][77]. Furthermore, reactors with mainly convective and conductive heat transfer such as fixed bed reactors [78,79], fluidized beds such as (conical) spouted beds [52,[80][81][82], bubbling/ stationary fluidized beds [51,53,55,56,63,83,84], fluidized beds with mechanical fluidization [85][86][87], and circulating fluidized bed reactors [88][89][90][91][92][93] have been applied to pyrolysis. Additionally, reactors that transport heat by means of radiation and convection: entrained flow reactors [94][95][96] and microwave pyrolysis reactors [97][98][99] have been used. ...
... Virtually all feedstock and reactor variations have been studied. Generally, the gas yield increases with rising temperature, because more feedstock is converted into volatile products and secondary reactions convert more pyrolysis oil to gas [51,56,84,126]. Complementarily, the char yield decreases continuously [51,56,84,126], while the oil yield increases until an optimum temperature is reached [51,56,84,119,[126][127][128]. Beyond this optimum, the secondary cracking reactions from oil to gas become more substantial [51,56,84,119,[126][127][128]. ...
... Generally, the gas yield increases with rising temperature, because more feedstock is converted into volatile products and secondary reactions convert more pyrolysis oil to gas [51,56,84,126]. Complementarily, the char yield decreases continuously [51,56,84,126], while the oil yield increases until an optimum temperature is reached [51,56,84,119,[126][127][128]. Beyond this optimum, the secondary cracking reactions from oil to gas become more substantial [51,56,84,119,[126][127][128]. ...
Book
In search of an alternative for chemicals and energy from fossil fuels, lignin pyrolysis is experimentally investigated in a circulating fluidized bed. Deviation in pyrolysis behavior of a softwood Kraft lignin and a wheat straw hydrolysis lignin is analyzed by means of char morphology as well as overall yield and composition determination for gas, oil, and char. The influence of catalytically active mineral matter in lignin on the product distribution is investigated. Progressively, the fluidized bed pyrolysis process is modeled semi-empirically considering fluid dynamics, feedstock composition, micro-particle pyrolysis reactions and mass balances. The lignin secondary reaction kinetics from oil–to–gas are obtained from the Kraft lignin experimental data and a pyrolysis plant with integrated char and permanent gas combustion is modeled with a flowsheeting tool.
... One of the best-known examples of using a fluidized bed reactor was Dynamotive, a company that resulted from the pioneering job conducted by the University of Waterloo. 11,12,146 In the design of most fluidized bed reactors in operation, the char is entrained A 10 ton/day mobile pyrolysis unit with a fluidized bed reactor has been developed by Agritherm at the University of Western Ontario (http://agri-therm.com). 16,42 An important feature of the design proposed by this company is its compactness, as the pyrolysis reactor is built using an annulus with a burner at the core to providing the energy needed for the pyrolysis process. ...
... (10) In the case of fluidized bed reactors, calculate or determine experimentally the minimum fluidization velocity (typically use 2−3 times the minimum fluidization velocity). 211,212 (11) Calculate the cross-sectional area and diameter of the reactor. 211 (12) In the case of fluidized bed reactors, calculate the volume of the expanded fluidized bed (sand and char particles). ...
Article
This paper provides a review of pyrolysis technologies, focusing on reactor designs and companies commercializing these technologies. The renewed interest in pyrolysis is driven by the potential to convert lignocellulosic materials into bio-oil and biochar and the use of these intermediates for the production of biofuels, biochemicals, and engineered biochars for environmental services. This review presents slow, intermediate, fast, and microwave pyrolysis as complementary technologies that share some commonalities in their designs. While slow pyrolysis technologies (traditional carbonization kilns) use wood trunks to produce char chunks for cooking, fast pyrolysis systems process small particles to maximize bio-oil yield. The realization of the environmental issues associated with the use of carbonization technologies and the technical difficulties of operating fast pyrolysis reactors using sand as the heating medium and large volumes of carrier gas, as well as the problems with refining the resulting highly oxygenated oils, are forcing the thermochemical conversion community to rethink the design and use of these reactors. Intermediate pyrolysis reactors (also known as converters) offer opportunities for the large-scale balanced production of char and bio-oil. The capacity of these reactors to process forest and agricultural wastes without much preprocessing is a clear advantage. Microwave pyrolysis is an option for modular small autonomous devices for solid waste management. Herein, the evolution of pyrolysis technology is presented from a historical perspective; thus, old and new innovative designs are discussed together.
... In addition, any tars sticking to the char would contribute to the measured char yield. For longer residence times, secondary reactions will result in the decomposition of the volatile vapours [10]. This clearly shows the sensitivity of yields to variations in fluidising flow and the need to optimise this variable. ...
... The results obtained are plotted and compared with literature data [6,[10][11][12] for a variety of biomass feedstocks as shown in Fig. 4. The low organic yields found in this work compared well with other high ash content ligno-cellulosic materials, particularly considering the high potassium content of EFB. ...
... DynaMotive's fast pyrolysis process evolved from experiments demonstrating flash pyrolysis of wood at the University of Waterloo in Canada [64,[79][80][81][82][83]. As shown in Fig. 4, the feed which is typically < 10 wt% moisture and < 3 mm in size, is fed into a bubbling fluidized bed reactor with a deep bed, which is heated to circa 430°C and has a gas residence time longer than 3 s [80,81]. ...
Article
Fast pyrolysis is a promising thermochemical method of producing renewable fuels and chemicals from biomass and waste feedstocks. There is much interest in optimising the choice of feedstock pre-treatments, reaction conditions, reactor designs, and catalysts as well as product upgrading steps to improve the techno-economic feasibility of the process. This article summarizes the current state-of-art in thermal and catalytic fast pyrolysis and outlines the major considerations for process development. The status of process technologies and development efforts on thermal and catalytic fast pyrolysis are reviewed, with a focus on efforts producing bio-oil for use in manufacturing transport fuels or fuel blends as the final product. The leading thermal pyrolysis processes, which use circulating, bubbling, auger screw and rotating cone reactor technologies, are reviewed alongside recent research and development activities on catalytic fast pyrolysis. This review finds that several technologies for thermal fast pyrolysis are operating at commercial scale, while integrated process development efforts are just starting to focus on applying catalytic fast pyrolysis at pilot scale. Processes for catalytic fast pyrolysis, either via in-situ or ex-situ upgrading of the bio-oil vapours is an area currently receiving significant research and development interest. This processing route may enable the production of partially upgraded bio-crudes which are suitable for processing to final fuel products in centralized bio-refineries or for co-processing in petroleum refineries. However, there remains a lot of fundamental and laboratory work to be done to develop deeper understanding of the processes, so that the catalysts and reaction conditions can be optimized. New combinations of unit operations and possibly novel reactors will likely be required to economically convert biomass feedstocks into partially upgraded bio-crudes. Techno-economic assessment shows that bio-fuels from fast pyrolysis may be competitive with petroleum fuels in future, however there are currently only a handful of plants operating commercially.
... Pyrolysis is a thermochemical process that can be used to break down certain materials into a liquid product called bio-oil [2] . Although pyrolysis is an old technology, it has been attracting increasing attention compared with other thermochemical processes as a result of significant progress in the past decade [10,11] . However, pyrolysis technology still exhibits many defects. ...
... Early investigations into the pyrolytic conversion of biomass to liquids were carried out in the 1970s by various workers, for example, the work by Knight and co-workers, and by Garrett Corp. (continued by Occidental Petroleum) [9]. Additional impetus for further process studies was given by the development in the early 1980s of the Waterloo Fast Pyrolysis Process (WFPP) at the University of Waterloo, Canada, and by the development of an "ablative" pyrolysis method at the National Renewable Energy Laboratory in the United States [51]. ...
Chapter
Depletion of fossil fuels and environmental concerns are driving research in the field of renewable and environmentally sustainable substitutes. Among the various energy forms, biofuels are potential alternatives to fossil fuels in the transport sector. The conversion of advanced biomass (not in competition with food) into bio-oil can be achieved mainly by biological and thermochemical technologies, such as pyrolysis and hydrothermal liquefaction (HTL). In this regard, the extensive literature review has been performed in order to understand the status quo of both HTL and pyrolysis technologies in terms of the selection of the more suitable process for the producing the final product with the desired properties. This chapter covers scientific and technical developments toward improving the bio-oil yield, as well as the quality with the emphasis on the bio-oil upgrading. Furthermore, the chapter points out the main barriers to commercialization of both pyrolysis and HTL technologies for the future.
... mm grape residue and olive residue particles pyrolyzed at 500°C. On the other hand, some researchers showed that larger particles in pyrolysis decrease liquid yield and increase biochar yield [22,83,87]. NikAzar et al. [22] found out that size increase from 53 to 63 μm to 270-500 μm declined liquid yield from 53 to 38%. ...
... Some of the initial moisture content of the biomass evaporates while passing through the pipelines towards the combustion chamber. The rest of the moisture is evaporated during the initial phase of devolatilization reactions in the combustion chamber [23,[33][34][35][36]. Size distribution, shape, and density of biomass particles affect their flow properties, and kinetics of drying and thermal decomposition [18,25,[37][38][39]. ...
... Pyrolysis of biomass occurs in the temperature range of 350-550℃. The long polymeric chains of organic compounds in biomass is thermally fragmentized into smaller molecules, which generates three types of products: bio-oil, bio-char and Relative proportions of end products in pyrolysis of biomass [12] Three types of pyrolysis could be classified based on different process conditions: a) Slow pyrolysis b) Fast pyrolysis c) Flash pyrolysis Process temperature, heating rate and solid residence time, are key factors of definition on type of pyrolysis. Slow pyrolysis is characterized by high vapor residence time which could reach 5min to 30min. ...
Thesis
Full-text available
Bio-oil generated from biomass is becoming one of the most promising alternatives as potential energy sources to replace fossil fuels in the transportation sector. Fast pyrolysis of biomass is one of the most economically feasible ways to produce bio-oil according to recent research on thermochemical conversion of biomass. Upgrading of oils derived from to hydrocarbon fuels requires oxygen removal and molecular weight reduction. Catalytic cracking and hydrotreating are two efficient processes to upgrade bio-oil. Hydrotreating requires that hydrogen is added in the process to increase the H/C ratio of the product. Normally, catalytic fast pyrolysis and hydrotreating are two separated processes. In order to increase the energy efficiency of the process, exploring the fast pyrolysis of biomass with in-situ catalyst under the hydrogen atmosphere, i.e. catalytic hydropyrolysis shall be very interesting, and this is the objective of this work. In this work, biomass pyrolysis experiments using softwood have been performed in hydrogen and nitrogen atmospheres with/without catalyst. It was found that in the case of the H2 atmosphere, a higher yield on oil phase and a reduced water production is found. More oxygen was removed as CO and CO2. The catalytic fast pyrolysis (CFP) under H2 atmosphere also produce relatively more PAH (polyaromatic hydrocarbon) and less MAH (monoaromatic hydrocarbon) than under N2 atmosphere.
... Thermal conversion process include direct combustion to provide heat and electricity power [9], gasification to produce mainly syngas [10], which can also be used as fuel to generate electricity or steam, or used in basic chemical processes [11] and the generation of pyrolysis oil [12]. temperatures ranging from 400 to 600°C in the absence of oxygen [13]. Depending on the details of the operating conditions, the pyrolysis process can be divided into three classes: slow pyrolysis, fast or flash pyrolysis, and microwave pyrolysis. ...
Article
In order to obtain the most favorable pyrolysis process for producing the highest yield of syngas from a range of leaf plants, the techniques of slow pyrolysis, fast pyrolysis and microwave pyrolysis of apple tree leaves, bamboo leaves, cypress leaves, sycamore tree leaves, and winter green leaves were investigated. The results showed that microwave pyrolysis produced the highest gaseous product yields (hydrogen rich gas) on all the 5 different kinds of leaves The apple tree leaves, sycamore leaves and wintergreen leaves showed higher yields of gas products than bamboo leaves and cypress leaves across all forms of pyrolysis. The experimentally determined higher heating values (HHV) of bio-chars from different leaves ranged from 20 to 28 MJ/Kg, interestingly, which are comparable to some coals. For the same variety of leaves, the HHV of bio-chars via different pyrolysis processes did not change significantly. However, the HHV of bio-chars from different leaves behaved differently, with the bio-char from wintergreen leaves showing the highest HHV, which reached around 27 MJ/Kg; on the contrary, the HHV of bio-chars from bamboo leaves gave the lowest values, some 20-22 MJ/Kg. For the gaseous products, the total amount of H2, CO, CO2 and CH4 reached 95% from all 3 pyrolysis treatments. Importantly, compared with slow and fast pyrolysis, the microwave pyrolysis of different leaves shows the highest content of H2 and CO and the lowest contents of CO2. The HHV of gaseous products of different leaves, using the same pyrolysis treatment, showed similar values but noticeably different when the pyrolysis process is for the same leaves is changed. The HHV of gaseous products via microwave pyrolysis are the highest amongst the different pyrolysis processes with the gaseous products HHV via fast pyrolysis being the lowest. We therefore conclude that microwave pyrolysis is a highly effective and also a highly selective process for H2 rich gas production from natural leaves. Furthermore, the addition of acid, bases and salts as catalysts for the pyrolysis did not noticeably result in any significant activity and products changes during the microwave pyrolysis process.
... Biochar, also termed black carbon, agrichar and charcoal, is in general the solid residue produced by thermal degradation of organic matter in the absence of oxygen (Scott and Jan 1984). During the process, 20-50% of biomass C is converted to the recalcitrant forms of C, dominantly made up of condensed aromatic C including small and fragmented graphene sheets that are highly resistant to microbial degradation (Glaser et al. 2002). ...
Article
Full-text available
Biochar as a soil ameliorant has generated great interest for scientists in improving soil quality and carbon sequestration. The objective of this study was to investigate the persistent effects of biochar application on soil organic carbon (SOC) mineralization and soil-resistant carbon (Cr) in upland red soil. This experiment was conducted from September 2011 to May 2016. Biochar was applied only once in September 2011 at rates of 0, 2.5, 5, 10, 20, 30 and 40 t/ha in the field experiment, designated as treatments B0, B1, B2, B3, B4, B5 and B6. The chemical properties, dynamics of SOC mineralization and soil-resistant carbon (Cr) were measured at the 1st and 6th year after biochar application. The results were as follows: biochar application at rates of 30 and 40 t/ha (B5 and B6 treatments) distinctly increased soil pH value and available P relative to B0 in 2011. The pH value, available P, SOC, total N and C/N ratio in B4, B5 and B6 treatments were significantly higher compared with the B0 treatment, where the B6 treatment increased the pH value by 0.80 and C/N ratio by 3.88 while increasing available P, SOC and total N by 24.18, 76.29 and 19.78%, respectively, compared with the B0 treatment in 2016. The cumulative SOC mineralization (Cm) occupied around 4.62–6.91% of total organic carbon (Ct), which showed a declining trend in 2016 as compared to 2011. The Cm/Ct ratio also showed a declining trend with biochar amendment at both samplings. The Cr occupied around 26–46% of SOC and showed obviously increasing trends both in 2011 and 2016. We further found that Cm/Ct showed highly significant (p < 0.01) negative correlations with the rates of biochar application both in 2011 and 2016. The Cr, however, showed very significant (p < 0.01) positive correlations with the rates of biochar application both in 2011 and 2016. This study suggested that biochar application to upland red soil persistently improved soil properties and resistant carbon. Cumulative SOC mineralization was clearly restrained by biochar amendment. This study can provide scientific support for improving soil fertility and enhancing carbon sequestration by application of large amount of biochar (40 t/ha) in upland red soil.
... Fast pyrolysis of biomass is a well-developed technology, which can produce bio-oil at yields 38 up to ~60 wt.% (water-free) [1][2][3][4][5][6]. The integration of biomass-derived pyrolysis oils in existing 39 oil refineries is a potential near-term solution for decreasing our dependence on crude oil and 40 ...
Article
Atmospheric hydrodeoxygenation (HDO) of wheat straw fast pyrolysis vapors was studied as a promising route for the production of renewable liquid transportation fuels. The performance of TiO2-supported Pt (0.5 wt.%) and MoO3 (10 wt.%) catalysts was compared to an industrial Mo-based catalyst using a bench scale reactor operated at atmospheric pressure and up to high biomass-to-catalyst ratios (B:C). Mass and energy balances were complemented by detailed bio-oil characterization including advanced methods such as GC×GC-ToF/MS or−FID and ¹³C NMR. At 50 vol.% H2, all three HDO catalysts effectively reduced the oxygen content of the bio-oils to ~7-12 wt.% (dry basis) compared to a non-catalytic reference (23 wt.% O). MoO3/TiO2 was least efficient in conversion of acids (TAN = 28 mg/KOH), while Pt/TiO2 and MoO3/Al2O3 obtained oils with TAN ~13 mg KOH/g (non-catalytic = 66 mg KOH/g). Compared to the TiO2-supported catalysts, the industrial Mo/Al2O3 catalyst produced higher yields of coke at the expense of condensed bio-oil. MoO3/TiO2 performed similar to Pt/TiO2 in terms of deoxygenation and energy recovery of condensed bio-oil, and by increasing the H2 concentration to 90 vol.% the energy recovery of bio-oil increased to 39 and 42% at 8 and 10 wt.% O (d.b.), respectively. Pt/TiO2 showed the highest selectivity to aliphatics and the lowest coke yields, e.g. the coke yield at B:C ~8 was only 0.6 wt.% of fed biomass. This study demonstrates that by using low-pressures of hydrogen and appropriate HDO catalysts, the quality of bio-oil can be improved without severely compromising its quantity (carbon yield) as observed under catalytic fast pyrolysis conditions.
... The char is carried out of the reactor body by the fluidising gas flow known as 'blow-through' mode [27]. The char is then separated from the product stream in a cyclone. ...
... Biochar, as a key technology, has been widely added to farmland soils to moderate global climate change. Produced by the thermochemical conversation of organic residues in an oxygen-limited environment [2], biochar is highly resistant to degradation due to recalcitrant carbon, and it has the potential to improve soil quality [3]. The addition of biochar has been documented to alter the soil porosity, moisture content, pH, labile C and N pool sizes, which would markedly impact soil CO 2 emissions [4,5]. ...
Article
Full-text available
Biochar amendments to soil have potential as a climate change mitigation strategy. However, their effect on carbon exchange in different ecosystems has not been well evaluated. Understanding how biochar affects carbon exchange from agricultural soil is essential for clarifying the contribution of biochar management to the carbon budget. We performed a laboratory and a two-year field experiment to investigate the short- and medium-term effects of biochar application on CO2 emissions from semiarid farmland. There was no statistically significant alteration in the cumulative CO2 emissions from the mixture of soil with biochar alone, while the emissions increased significantly with additional nitrogen amendment over the 46-day experimental period. Over the two-year experimental period, the cumulative CO2 emissions from the field experiment decreased in the biochar-amended treatment, and the effects were significant at high application rates (20 and 30 t·ha−1) relative to the control in the MS. The seasonal CO2 dynamics were strongly dependent on soil temperature, with a higher correlation with the temperature at a depth of 10cm than with the temperature at a depth of 0cm. Soil temperature, rather than soil water content, was the major environmental factor controlling the soil carbon exchange in the semiarid farmland of the Loess Plateau. In general, biochar additions enhanced aboveground dry matter accumulation in both the early and late stages of maize growth. The results suggested that biochar amendment was a preferable management practice to help maintain or increase carbon sequestration for this region with lower CO2 emissions and higher dry matter production over a longer period.
... Early research on biomass pyrolysis in fluidised beds was pioneered by the researchers at the University of Waterloo in Canada (Scott and Piskorz, 1982;Scott and Piskorz, 1984;Scott et al., 1985) which led to the development of RTI process (Scott et al., 1999). Based on the RTI process, Dynamotive built a 100 tonne per day and 200 tonne per day plants in Canada (Bridgwater, 2012). ...
Thesis
Global challenges related to energy security, resource sustainability and the environmental impacts of burning fossil fuels have led to an increasing need for switching to the use of clean and sustainable resources. Bio-oil produced through pyrolysis has been suggested as one of the sustainable alternatives to fossil resources for power generation as well as chemicals and biofuels production. Pyrolysis is a thermochemical process during which the biomass feedstock is heated in an inert atmosphere to produce gas, liquid (bio-oil) and solid (char) products. Microwave heating has been considered a promising technique for providing the energy required for biomass pyrolysis due to its volumetric and selective heating nature which allows for rapid heating in a cold environment. This helps to preserve the product quality by limiting secondary reactions. The aim of this research was to study the interactions between biomass materials and microwave energy during pyrolysis, and to develop a reliable and scalable microwave pyrolysis process. The dielectric properties of selected biomass materials were studied and found to vary significantly with temperature due to the physical and structural changes happening during pyrolysis. The loss factor of the biomass materials was found to reach a minimum value in the range between 300 oC and 400 oC followed by a sharp increase caused by the char formation. A microwave fluidised bed process was introduced as an attempt to overcome the challenges facing the scaling-up of microwave pyrolysis. The concept of microwave pyrolysis in a fluidised bed process was examined for the first time in this thesis. A systematic approach was followed for the process design taking into account the pyrolysis reaction requirements, the microwave-material interactions and the fluidisation behaviour of the biomass particles. The steps of the process design involved studying the fluidisation behaviour of selected biomass materials, theoretical analysis of the heat transfer in the fluidised bed, and electromagnetic simulations to support the cavity design. The developed process was built, and batch pyrolysis experiments were carried out to assess the yield and quality of the product as well as the energy requirement. Around 60 % to 70 % solid pyrolysed was achieved with 3.5 kJ·g-1 to 4.2 kJ·g-1 energy input. The developed microwave fluidised bed process has shown an ability to overcome many of the challenges associated with microwave pyrolysis of biomass including improvement in heating uniformity and ability to control the solid deposition in the process, placing it as a viable candidate for scaling-up. However, it was found to have some weaknesses including its limitations with regards to the size and shape of the biomass feed. Microwave pyrolysis of biomass submerged in a hydrocarbon liquid was introduced for the first time in this thesis as a potential alternative to overcome some of the limitations of the gas-based fluidised bed process. Batch pyrolysis experiments of wood blocks submerged in different hydrocarbon liquids showed that up 50 % solid pyrolysis could be achieved with only 1.9 kJ·g-1 energy input. It was found that the overall degree of pyrolysis obtained in the liquid system is lower than that obtained from the fluidised bed system. This was attributed to the large temperature gradient between the centre of the biomass particle/block and its surface in the liquid system leaving a considerable fraction of the outer layer of the block unpyrolysed. It was shown that the proposed liquid system was able to overcome many of the limitations of the gas-based systems.
... It is a process in which the pyrolysis reactor works on a very unique principle in which the char is not allowed to accumulate in the bed while the treatment of the sand may not be necessary. One big advantage of the process is that the liquid product obtained is usually acid and pours easily with relative stability [51]. ...
... This fact can be attributed to the increase of the heating rate of the sewage 309 sludge particles [9,35] caused by the higher axial fuel mixing obtained when the 310 fluidizing gas velocity is increased [14,15]. Comparing the experimental 311 measurements obtained for both reactor temperatures, a slight effect of the 312 temperature can be observed, accelerating scarcely the pyrolysis process when 313 increasing the reactor temperature from 500 ºC to 600 ºC. ...
Article
Full-text available
Pyrolysis of sewage sludge was studied experimentally in a stainless-steel reactor operated as a fixed or fluidized bed. A novel measuring technique, consisting of measuring the mass of the whole reactor and the sample on a scale, was applied. The scale was capable of measuring the whole mass of the reactor with enough accuracy to detect the mass released by the sewage sludge sample during its pyrolysis. This original measuring technique permitted the measurement of the evolution over time of the mass of sewage sludge supplied to the bed in batch during its pyrolysis while moving freely in the bed. From the measurement of the mass of the solid residue remaining in the reactor, the pyrolysis time of the sewage sludge sample can be obtained accurately for each operating condition. Different operating conditions were selected to analyze the evolution with time of the sample mass during the pyrolysis process, including the bed temperature and the velocity of the Nitrogen used as inert gas. An increase of the velocity of Nitrogen from that of a fixed bed (0.8Umf) to that of a low velocity bubbling fluidized bed (2.5Umf) accelerates remarkably the pyrolysis process, i.e. reduces the pyrolysis time, however increasing the Nitrogen velocity further has a slight effect on the characteristic velocity of the pyrolysis process. The pyrolysis process of sewage sludge can also be accelerated by increasing the bed temperature, even though the effect of the temperature is lower than that of the Nitrogen velocity. Furthermore, a mathematical model based on a first order apparent kinetics for the pyrolysis of sewage sludge was proposed. The model was employed to estimate the pyrolysis time for each operating condition, obtaining a proper agreement with the experimental measurements.
... In the pyrolysis process, the bulk density of the biomass particles is one of the key parameters for designing the pyrolysis reactor and feeding system of continuous pyrolysis systems. Beside the reactor size, the bulk density of biomass also directly influences energy density (MJ/m 3 ), storage area requirement and cost, and transportation cost [72][73][74][75]. Table 2 shows the results of the proximate analysis, including the moisture content (MC), volatile matter (VM), fixed carbon content (FC), and ash content (AC) of the OPB samples. ...
Article
Full-text available
The objective of this work is to evaluate the potential of oil palm biomass (OPB) in terms of physicochemical properties for producing biofuels via pyrolysis processes. The OPB included oil palm trunk (OPT), oil palm fronds (OPF), oil palm shell (OPS), oil palm roots (OPR), oil palm decanter cake (OPDC), empty fruit bunches (EFB), oil palm fiber (OPFB), and oil palm sewage sludge (OPSS). Their physicochemical properties are considered on several physical, chemical, and thermal aspects. The results showed that particle size distribution and bulk density of ground OPB were different. The proximate analysis results of OPB were consistent with the lignocellulose content and extractives. The carbon and hydrogen content of the OPB were also correlated with the organic components. Some OPB contained high lignin and extractives. The lignin content of OPB strongly influenced to thermal decomposition trend. OPB contained high inorganic elements such as potassium (K), calcium (C), and iron (Fe). The higher heating value and potential use as energy equivalent with fossil fuels of the OPB were relatively low. OPB had low thermal conductivity, and the dielectric constant, loss factor, and tangent loss of the OPB were also low. Thus, these results will be beneficial for the researchers and biofuel producers for choosing the appropriate OPB, as well as the operating conditions and reactor types.
... Intensive agriculture is one of the biggest causes to the growth in GHGs (Melillo, 2002). Approximately 12% of annual GHG emissions come directly from soil, with soil accounting for 39% (Mofijur et al., 2013;Scott, 1984). The impact of Biochar on carbon exchange in various ecosystems throughout the world has yet to be fully assessed. ...
Article
Full-text available
Asian Countries mostly lying in Subcontinent region are the main producers of Sugar canes. On the other hand, these are the developing countries which mostly face potential energy crisis which ultimately gives rise to sustainable electricity demand challenges. This challenge can be mitigated through the conventional way of bagasse-based cogeneration of power. Therefore, sugar industries can contribute in fulfilling at least their own requirement of plant electricity. But this method in turn produces carbon dioxide (CO 2) to the environment which is a major source of Green House gas (GHG) emissions globally. So, it is the most significant contributor to the global warming, which plays diverse impact on social, environmental, and economic costs. So far, the increasing concentrations of GHGs in the atmosphere are a notable issue. Biochar is one of the products of flash pyrolysis which reduces the GHG emissions and enhancement of soil fertility. This paper proposes flash pyrolysis as a sustainable way of meeting electricity demand with additional benefits over conventional way of burning bagasse in cogeneration, giving the environmental and economic benefits of pyrolysis. Bagasse gasification by flash pyrolysis in the sugar mills could be an alternative option for electricity generation with CO 2 negative impact.
... The obtained bio-oil product shows that the deoxygenation degree is at the same level as achieved in experiments concerned with catalytic pyrolysis of biomass [11], suggesting that catalysis is not required at all. These findings, however, are not supported with the results of earlier reports on biomass fast pyrolysis employing NCGs as reaction atmosphere (typically as a fluidization gas) at lab-scale [12][13][14][15][16], process development units [17,18] or commercial scale [19,20]. These studies, however, were not aimed at investigating the effect of gas recy cling. ...
Article
It has been reported that a deoxygenated bio-oil (ca. 0.12 kg kg⁻¹ O on bio-oil basis) can be obtained simply by recycling the non-condensable gases (NCG) of biomass fast pyrolysis to a fluidized-bed reactor operated at atmospheric pressure [Mullen et al., 2013, Energy Fuels, 27, 3867–3874]. Such an unprecedented effect would (i) complicate the use of lab-scale research results obtained typically under inert gas (N2, He, Ar) atmosphere for the design of commercial scale pyrolysis units projected to utilize a recycle gas atmosphere (ii) obviate the need for catalytic pyrolysis or mild hydrotreatment processes. Considering these implications, further validation or refutation of the claimed deoxygenation effect of recycle gas atmosphere is needed. Therefore, fast pyrolysis experiments with pine wood were performed in a bench-scale fluidized bed reactor under N2 atmosphere, recycle gas atmospheres (75 % and 90 % recycle gas volume fraction) at reactor temperatures of 430 °C and 500 °C. Mass balances were obtained and the bio-oils were analyzed using GC/MS, GPC, elemental analysis and Karl Fischer titration. No significant differences were observed in product yield and bio-oil composition (e.g. oxygen content) when going from a nitrogen gas atmosphere to a recycle gas atmosphere for both pyrolysis temperatures.
... To data, a variety of processes and demonstration devices have been developed, but the industrialization progress is slow. In terms of the pioneering work in reactor types, the fluidized bed reactor of the University of Waterloo in Canada [44], the unique rotating cone reactor of the University of Twente in the Netherlands [45], and the Free-Fall reactor of Swiss [46] have all achieved the goal of maximizing the yield of liquid products. ...
Article
The growing environmental concerns and the prospect of irreversible climate change highlight the necessity for the rapid transformation from fossil-based economy to the modern circular bio-based economy. Yet the urgency of green transformation may lead to insufficient consideration of scientific concerns about the sustainability of accelerated biomass deployment, and the inherent complexity and uncertainty in the assessment present a challenge to policy makers, researchers, and industry. This review aims to provide a retrospect towards the status of biomass resources from the feedstock to conversion process, and end-use. Understanding the distribution and potential projections of major biomass types are also critical steps to ensuring sustainable supply chains. A novel indicator framework was further established for assessing the sustainability of biomass resources by integrating the environmental and social-economic dimensions. Different indicators are interdependently connected and vary significantly among the feedstock categories, land use types and management practices. All of which are important considerations of the criteria for systematic research in the future, understanding the alternative potential of biomass resources, providing important insights for accelerating the transition to bio-based economy, as well as policy regulation.
... Polyethylene garbage was collected around campus, and the sample was cleaned with water to eliminate contaminants before being sundried. To increase the surface area available for pyrolysis, the sample was chopped into smaller pieces (Scott & Piskorz, 2014). The pyrolysis experiment was carried out in an airtight cylindrical reactor made of stainless steel (length 210mm, inner diameter 22mm) with connecting pipes flowing in and out for gas conveyance and product collection, respectively (Diebold, 1999). ...
... An alternative option is ex-situ catalytic fast pyrolysis (CFP), in which the vapors produced by thermal pyrolysis are converted on a catalyst before their condensation, at atmospheric pressure [6]. In the first step, the fast pyrolysis of lignocellulosic biomass is realized at high temperature range (400− 600 • C) [7] with short residence time (~1 s) [8]. Then, in a second step, the vapors are driven on the catalytic bed where the upgrading reactions occur. ...
... The flash pyrolysis process with continuous atmospheric pressure for the production of organic liquids from cellulosic biomass was carried out using feeding rate of 1 ~ 3 kg/h of dry feed. The high organic liquid oil yield (65% ~ 70 %) from the dry feed of hardwood waste material, and 45% ~ 50 % liquid oil yield from wheat straw were obtained [57]. Urban et al. [58] conducted flash pyrolysis of oleaginous biomass feedstock to produce liquid fuel in a laboratory scale fluidized bed reactor using temperature range of 250 ~ 610 • C and with a vapor residence time of 0.2 ~ 0.3 s. ...
Article
A long-term and reliable plastic waste management scheme is required to avoid environmental pollution and to overcome the issues of energy crisis simultaneously. Pyrolysis of plastic waste is a thermo-chemical disposal procedure that helps alleviate these issues while recycling valuable commodities such as oil and gas. This article reviewed the current scenario of plastic waste throughout the world, various methods of pyrolysis as well as the products produced from plastic waste pyrolysis. The results showed that the global plastics demands are increasing by 5% every year, causing larger amount of plastic wastes generation. The quantities and characteristics of pyrolysis products were significantly affected by plastic type, pyrolysis method (slow pyrolysis, fast pyrolysis and flash pyrolysis), reactor type, particle size, etc. Liquid oil is the primary product of plastic waste pyrolysis with up to 90 wt%, whereas gases (3 ∼ 90.2 wt%), wax (0.4 ∼ 92 wt%), char (0.5 ∼ 78 wt%) and HCl (0.1 ∼ 58 wt%) are the by-products. The liquid oils produced from plastic waste pyrolysis have similar properties to conventional diesel, i.e., viscosity (up to 2.96 mm²/s), density (0.8 kg/m³), flash point (30.5 °C), cloud point (−18 °C) and energy content (41.58 MJ/kg).
... An alternative option is ex-situ catalytic fast pyrolysis (CFP), in which the vapors produced by thermal pyrolysis are converted on a catalyst before their condensation, at atmospheric pressure [6]. In the first step, the fast pyrolysis of lignocellulosic biomass is realized at high temperature range (400− 600 • C) [7] with short residence time (~1 s) [8]. Then, in a second step, the vapors are driven on the catalytic bed where the upgrading reactions occur. ...
Article
Ex-situ catalytic fast pyrolysis (CFP) was employed to produce bio-oils from beech wood. The effect of Nb-based mixed oxides (with second metal oxide = W, Al or Mn) in upgrading the pyrolysis vapors was compared to an H-ZSM-5 catalyst and to non-catalyzed pyrolysis. The catalysts acidic properties were assessed by NH3-TPD and FTIR of adsorbed pyridine. The bio-oils obtained were characterized by Karl-Fischer titration, GPC, CHNS analyses, ¹³C-NMR, GC-MS, GCxGC-MS. In spite their very different acidic properties, the NbxMnyOz catalyst (with essentially Lewis acid sites) exhibited similar performances as H-ZSM-5 (that presents a high density of Brønsted sites), in terms of liquid phase selectivity and reduction of oxygen content in the bio-oils produced. These observations were accompanied by a reduction of compounds such as acids, aldehydes, ketones, ethers and sugars that contribute to the detrimental properties of bio-oils. Finally, the results suggest that the Lewis acid sites of NbxMnyOz are converted into Brønsted sites in the presence of water vapor produced by pyrolysis of wood, whereas the strongest Brønsted sites of H-ZSM-5 have a limited impact on the upgrading process due to their limited accessibility for most components of pyrolysis vapors.
... As SRFs may be rich in plastics, the gasification performed at relatively high heating rate was proved to promote the release of HCN [61]. While part of the nitrogenous compounds can be in the form of tar [62] and char [63] after pyrolysis, secondary reactions can transform these nitrogenous compounds into HCN during gasification [64]. In addition, the drop of NH 3 release with increasing temperature can be attributed to the thermal decomposition of NH 3 into N 2 [65]. ...
Article
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The influence of the gasification temperature and Equivalence Ratio (ER) on the behavior of an industrial low-grade Solid Recovered Fuel (SRF) was investigated in an air bubbling fluidized bed. The studied SRF exhibits an intermediate composition between biomass-rich SRF and plastic-rich SRF. Its Lower Heating Value (14 MJ/kg) is low since its ash content is very high (35 wt%). But surprisingly, the Cold Gas Efficiency and the Carbon Conversion were relatively high with this type of low-grade SRF. As a result, the syngas produced is quite rich (LHV > 8 MJ/m³ STP) and it may be valorized in gas engines. H2S, HCl, HCN and NH3 in the syngas were analyzed. These results confirm that inorganic gases are an important issue for the valorization of SRF as fuel in gasification processes, even if significant parts of S, N and Cl are not converted into inorganic gases. Graphic Abstract
... Among this, fast pyrolysis (FasP) was one of the main technologies for preparing the bio-oil (Sun et al., 2018). FasP is the process with thermal decomposition under a moderate temperature of 300 -700 in the reaction zone without oxygen (Bridgwater and Peacocke, 1999;Scott and Piskorz, 1984). The reactor configurations include bubbling fluid beds (Robson, 2001;Scott et al., 1985), circulating and transported beds (Graham et al., 1988;Wegenaar et al., 2000), cyclonic reactors (Czernik et al., 1995;Diebold and Scahill, 1988), and ablative reactors (Peacocke and Bridgwater, 1996), which play an important role in this process to ensure the production. ...
Article
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The objective of this paper is to establish the state of knowledge on fast pyrolysis of bio-oil and bio-asphalt binder and to facilitate efforts in improving the overall performance of bio-asphalt and maximizing its road application. On the basis of reviewing the relevant literature recently, the fast pyrolysis (FasP) preparation process of bio-oil and its main properties, the preparation process of bio-asphalt and its performance and the application of bio-asphalt have been summarized. Due to the variations in raw materials, the adopted methods of FasP to prepare bio-oil could be different, and the properties of bio-oil from different sources are also different. At present, the plant-based bio-oil (mainly derived from wood waste and sawdust) has been widely used to prepare the bio-asphalt. Research on the low-temperature flexibility, high-temperature rheology, workability and other performance of biological asphalt showed that the workability and high-temperature performance of most asphalt are improved after adding bio-oil. However, the low-temperature performance is found to relatively reduce. Also, with regards to its application as a rejuvenator, bio-oil can considerably rejuvenate the aged asphalt’s mixture performance. By far, most of research on bio-asphalt is still focused on the performance of bio-asphalt binder in the laboratory; its application in practical road engineering is still to be examined. This review also provides an outlook for the future, for example, establishing an integrated preparation process from bio-oil to bio-asphalt, and evaluating the properties of bio-asphalt by new standards.
... It was reported [69] that particle size of biomass feedstock played a significant role in the heating rate of solid fuel, controlling the rates of drying and primary pyrolysis. Larger feedstock particles would result in lower yields of liquids during pyrolysis process [208,209]. In addition, the smaller the particle size is, the more it cost. ...
Article
Climate change, a serious environmental problem arises with global warming, rooting in the overuse of fossil fuel and affecting numerous people all over the world. However, the demands human makes on the natural resources will grow even faster. Lignocellulosic biomass is the largest and most sustainable energy source but has not been utilized well. Therefore, requirements for full utilization of renewable bioenergy sources and practical application of recycle-bioenergy technologies are extremely urgent. Anaerobic digestion and pyrolysis are two promising technologies to degrade lignocellulosic biomass, producing multiple value-added and renewable bioenergy products. The integration of anaerobic digestion and pyrolysis is a new concept appearing in recent years but has drawn much attention from researchers. It is suggested that the integration will open up new interesting pathways for combining biological and thermochemical processes to obtain higher bioenergy recovery from lignocellulosic biomass. This paper briefly reviews recent development and the feasibility of integrated processes. The integration of anaerobic digestion and pyrolysis is designed for giving a full play to advantages of them, achieving significant efficiency gains and maximizing the bioenergy yields extracted from a certain amount of lignocellulosic biomass. Besides, the effects of significant process factors on the yields and properties of bioproducts are introduced. Further optimizations and future challenges for integrated processes are also mentioned.
... For example, the chemical composition of the bio-oil also varied with the temperature in terms of percentage of acetaldehyde, ethanol, acetic acid, acetone, furan, methanol, and formaldehyde, among others. The flash pyrolysis of maple wood was also studied by Scott and Piskorz [101]. By increasing the temperature (from 482 to 532°C), the percentage of biochar was reduced, whereas bio-oil and gas contents were increased with varied physicochemical properties. ...
Article
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Purpose of Review For the past few decades, consumers have increasingly demanded biodegradable, petroleum-free, and safe products for the environment, humans, and animals, with improved performance. In terms of energy consumption, modern society has progressively sought to reduce fossil fuel utilization and greenhouse gas emissions. This review presents and discusses the possibilities of using biomass residues that are derived from forest operations and wood manufacturing to produce biofuels and biomaterials as sustainable alternatives that could boost the development of renewable technologies and bio-economy. Recent Findings Forest biomass residues are composed primarily of cellulose, hemicellulose, and lignin in varying proportions depending upon the species. Residues from forest operations have heterogeneous compositions due to the presence of branches, foliage, tree tops, and bark, compared with those derived from wood manufacturing industries. Several technological approaches have been developed to add value to forest biomass residues through their conversion to biomaterials such as wood-based composite panels, wood-plastic composites, wood pellets, and biofuels, such as biochar, bio-oil, syngas (thermochemical approach), and biogas (biochemical approach). Summary Forest biomass residues are valuable lignocellulosic materials, but research is still required regarding their conversion into value-added products given their heterogeneous compositions and varied physicochemical properties. Obstacles such as transportation costs and their complex structural and chemical mechanisms that resist decomposition need to be better overcome in developing high-quality and economically viable biofuels and biomaterials. In contrast, wood-based panels, composites, pellets, and biofuels produced by the wood manufacturing industries exhibit superior properties and characteristics for commercialization. Recent studies regarding valorization of forest biomass residues are a welcome recognition of the need to transition to a sustainable economy, and a definitive strategy for achieving objectives that have been set for reducing greenhouse gas emissions.
Chapter
Concerns over climate change coupled with the desire to develop an economy based on renewable and sustainable feedstocks have catalyzed interest in developing pathways and technologies for production of bio-based energy and bio-based products. Biomass utilization plays an important role in this picture since biomass is the only renewable energy source that can offer a direct (e.g., drop-in) replacement for fossil-based transportation fuels in the near to mid term. The United States alone has the capacity to produce more than one billion tons of sustainable biomass, which can be used to produce transportation fuels with dramatically reduced carbon footprints, bio-based chemicals to replace petroleum-derived analogs, and renewable electrical power. A bio-based economy can serve to create new economic opportunities and jobs while simultaneously reducing future climate impacts.
Article
In this study, the pyrolysis of several Canadian straw biomasses was studied using a thermogravimetric analyzer and a bench-scale horizontal fixed-bed reactor, in order to better understand the devolatilization process and to obtain information about the product yields of these biomasses. The straw biomasses were converted through pyrolysis performed in a fixed-bed reactor at temperatures of 500 °C to study the influence of the feedstock on product yields. The effects of various catalysts on product yields are also discussed. When using zeolite catalysts, the bio-oil and bio-char yields of the straw pyrolysis were increased to 46.44% and 38.77%, respectively, while the bio-gas yield was decreased to 13.65%. The use of catalyst zeolite ZY-SS had the most significant effect on overall bio-oil and bio-char yields, increasing the bio-oil yield by about 2% and the bio-char yield by 8%. This catalyst had the most significant effect on the pyrolysis of flax straw, where the bio-oil yield was increased to 46.44%. In the pyrolysis of oat straw, the use of the catalyst consistently decreased the bio-gas yield; however, the bio-oil yield increased the most significantly (43.32%) with the use of catalyst zeolite ZY-NS. The use of zeolite ZY-NS also increased the bio-oil yield during the pyrolysis of barley straw (43.03%).
Article
Pyrolysis is a thermo-chemical decomposition process that converts organic or inorganic materials into solid, liquid and gaseous products. The pyrolysis process involves multiple complex chemical reactions, and the derived products are highly dependent on the pyrolysis operating parameters and type of feedstock. In the present review, progress on the state-of-the-art pyrolysis technology, feedstock and properties of the end products are thoroughly reviewed. The potential application of the pyrolysis products in the industries is discussed: solid leftover can be upgraded and used as a bio-adsorbant, soil amendment, fertilizer or solid fuel; pyrolysis liquid can be used as a bio-chemical source or upgraded into liquid fuel; gaseous products can be used as recirculating gas for the pyrolysis environment or burnt as fuel for heat and power generation. Despite the potential of pyrolysis in processing agricultural or industrial wastes, studies regarding the economic feasibility and environment sustainability of scaled-up pyrolysis plant are scarce. A comprehensive overview on the type of pyrolysis reactor technology, potential feedstock and the properties of the derived products is presented. Further, the sustainability of the technology is assessed from the aspects of energy balance, environment and economics. In spite of the potential benefits to the environment and recovery of valuable products, there are several challenges that need to be addressed to ensure the sustainability and commercialibility of the pyrolysis technologies.
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The paper reviews the history of production and application of bio-oil (pyrolysis oil), describes its differences from other types of fuel and chemical feedstock, and considers problems associated with classifying and defining bio-oil and biofuel. The basic physicochemical properties of bio-oil are described, along with a demonstration of their variation depending on the used feedstock. Finally, methods for obtaining bio-oil and modifying its properties are outlined in relation to the primary areas of bio-oil use.
Chapter
Energy is vital for human growth. The exponential rise in the energy demand is fulfilled from fossil fuels which disturbs the ecological imbalance and threatens climate changes, human health, and greenhouse gas emissions. The search for renewable energy sources can overcome these issues. Biomass includes grass, agricultural waste, domestic waste, wood can be converted into biofuels and Bioenergy. Physical or Mechanical, Biological, and Thermochemical routes are used to convert the biomass into value-added products. Thermochemical conversion processes gained more attention as compared to biological conversion processes due to their advantages. In the Thermochemical process, the reaction time is less, i.e., few seconds and minutes, while the biological process is slow and reaction is carried out in hours, days and weeks, or years. The product obtained from the thermochemical conversion is a multiple and complex product mixture (bio-oil), while ethanol or biogas is the final product of the biological process. The various thermochemical techniques are Combustion, Gasification, and Pyrolysis. Combustion is biomass burning in air/oxygen to get heat for steam production and generation of electricity. The burning of biomass in partial oxidation is known as gasification. Fuel gas consists of Carbon dioxide, Carbon monoxide, Hydrogen, and Methane, obtained as gasification product and used to generate heat and electricity. Pyrolysis is biomass thermal disintegration process done in the absence of oxygen. Gas, Liquid (bio-oil) and Solid (biochar) are the products of the pyrolysis process and have various industrial applications. There are different pyrolysis processes and can be categorized based on the requirement and utilization of the products. This chapter includes the various pyrolysis technologies reported earlier along with the recent advancement in this process. This chapter emphasizes the emerging pyrolysis technology and commercial plants available worldwide used to produce liquid fuels.
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In the future, renewable energy technologies will have a significant role in catering to energy security concerns and a safe environment. Among the various renewable energy sources available, biomass has high accessibility and is considered a carbon-neutral source. Pyrolysis technology is a thermo-chemical route for converting biomass to many useful products (biochar, bio-oil, and combustible pyrolysis gases). The composition and relative product yield depend on the pyrolysis technology adopted. The present review paper evaluates various types of biomass pyrolysis. Fast pyrolysis, slow pyrolysis, and advanced pyrolysis techniques concerning different pyrolyzer reactors have been reviewed from the literature and are presented to broaden the scope of its selection and application for future studies and research. Slow pyrolysis can deliver superior ecological welfare because it provides additional bio-char yield using auger and rotary kiln reactors. Fast pyrolysis can produce bio-oil, primarily via bubbling and circulating fluidized bed reactors. Advanced pyrolysis processes have good potential to provide high prosperity for specific applications. The success of pyrolysis depends strongly on the selection of a specific reactor as a pyrolyzer based on the desired product and feedstock specifications.
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The effect of the kinetic model of the thermal decomposition of wood on the results of prognostic modeling of the ignition of wood particles was analyzed. The results of mathematical modeling were verified by experimental studies of the ignition of wood particles in a high-temperature environment. Comparative analysis of theoretical and experimental ignition delays shows that they are in good agreement. The prognostic potential of three substantially different kinetic models of wood pyrolysis was analyzed. The model of one-step pyrolysis involving the formation of gaseous reaction products adequately describes thermal decomposition during thermal preparation in the whole range of heating conditions (the deviation from the times obtained using the three-step pyrolysis model does not exceed 5%). Numerical simulation results show that accounting for the thermal decomposition reactions of the second and third levels with the formation of intermediate (liquid and solid) pyrolysis products does not have a significant influence on the characteristics and conditions of ignition of wood particles in a high-temperature gas environment.
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A sustainable solution to biomass burning by converting agricultural residues into biochar was provided. Biochar application was investigated to improve soil fertility, sequester carbon, and increase crop production. Rice husk (RHBC) and corn stover (CSBC) biochars were obtained by slow pyrolysis at 650° and 550 °C, respectively. RHBC and CSBC were characterized (SEM, SEM-EDX, TEM, FTIR, XRD, elemental analyses, and SBET). Unpyrolyzed husks and stover were also used for soil amendments and compared to biochars in different proportions under a controlled incubation environment over 107 days. Fertilizers were not applied. An increase in water holding capacity, total organic carbon, cation exchange capacity, and a decrease in soil CO2 emission were observed after biochar application to soil versus the application of the parent husks or stover. These biochars improved soil fertility and enhanced eggplant crop growth (height, leaf number, fresh and dry weight). In addition, carbon mitigation was achieved because the biochar remained stable in the soil achieving longer term carbon sequestration. Both chars can be used for carbon sequestration and soil amendments.
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This review covers the characteristics of pyrolysis and catalytic pyrolysis bio‐oils by focusing on the fundamental factors that determine bio‐oil upgradability. The abundant works on the subject of bio‐oil production from lignocellulosic biomass were studied to establish the essential attributes of the bio‐oils for assessment of the oil stability and upgradability. Bio‐oils from catalytic pyrolysis processes relating to catalysts of different compositions and structures are discussed. A general relationship between the higher heating value and the oxygen content in the catalytic pyrolysis oils exists, but this relationship does not apply to the thermal pyrolysis oil. Reporting bio‐oil yield is meaningful only when the oxygen content of the oil is measured because the pyrolytic oil stability is mainly determined by the oxygen content. Isoenergy plot that associates bio‐oil yield with oxygen content is presented and discussed.
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The commercial production of advanced fuels based on bio-oil gasification could be promising because the cost-effective transport of bio-oil could promote large-scale implementation of this biomass technology. So far there has no specialized review of bio-oil gasification processes, including non-catalytic partial oxidation of bio-oil for syngas production and steam gasification of bio-oil for hydrogen production. A detailed and comprehensive review of gasification of bio-oil for gas production is presented in this paper. The background and significance of bio-oil research, the characteristics of bio-oil suitable for gasification, bio-oil gasification theory, types and configurations of bio-oil gasifiers, the quality of the product gas, parameter effects, and economic evaluation of bio-oil gasification are discussed, and finally a summary and future outlook is also delivered. Particular emphasis is placed to on the discussion regarding the atomization of bio-oil, entrained flow gasifiers and their advantages, gas composition and the economic feasibility of production of advanced fuels via bio-oil gasification. Challenges for the future are identified as (1) make full use of the experience accumulated in the area of petroleum refining; (2) practical demonstration of bio-oil gasification on a scale of 500 to 1000 kg bio-oil per hour; (3) the development of mathematical models for bio-oil gasification systems; and (4) development of suitable catalysts and profoundly understand the catalysts deactivation mechanism at different stages for steam gasification of bio-oil.
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An estimated 8.3 billion tonnes of plastic waste has been generated globally since the 1950s of which approximately 80% remains in landfill or loose in the environment.1 Global greenhouse gas emissions from the production and disposal of plastics is more than double that of air travel.2 In line with current demand, oil-based plastics are produced at a rate of ~350mtpa. While useful, fossil-derived plastics have been developed focusing on function rather than end-of-life performance and their environmental impact. Recycling alone is not the complete answer to the "plastics problem". These include cost, food contamination, polymer degradation and environmental leakage. Bio-based plastics are an important part of the solution. This work demonstrates a novel approach to going some way towards solving the “plastic problem” by adding value to biomass pyrolysis liquids through transesterification of the diverse range of alcohol functional groups within the mixture to give rise to polymerizable monomers from biomass, without requiring extensive separation. Previous studies have worked on using highly reactive acyl chlorides/acid anhydrides on model compounds to achieve similar results. Using transesterification, production of the monomer is achieved in one reaction step and without separation or the use of toxic reagents. Strategies to tune the process to vary glass transition temperature (Tg) and Mp are discussed. A scheme of future work to exploit this in applications is included.
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The present work reports the physical, size and shape, flowability, drying and devolatilization properties of ground wood and ground bark particles. Mechanical sieving and image processing identify the size and shape of ground particles, respectively. Ground particles are dried at initial moisture contents of 0.30, 0.50, 0.70 and 0.90 (dry mass basis) and drying temperatures of 70, 100, 130 and 160 °C. Devolatilization rate of particles is measured using a thermogravimetric analyzer. Microscopic investigations show that wood particles are longer and thinner than bark particles. More spherical shape facilitates the flowability of the bark particles. Wood particles are cohesive and have poorer flowability properties than bark particles. Bark particles have a lower internal void fraction than wood particles. Denser structure of bark particles diminishes the drying and devolatilization rate and prolongs the heat and mass transfer process compared to the wood particles.
Article
Bio-energy is a major component of the global renewable energy market due to the low requirement for energy infrastructure modification and the high bio-energy productivity. Bio-ethanol production from sugar-rich biomass, biodiesel production from lipid-rich biomass, and biogas production from volatile-matter-dense feedstock have been commercialized. A substantial fraction of biomass waste, however, is still discarded due to high processing costs and low end-product values. This fraction includes agricultural wastes, dedicated plants, spent grains, de-oiled seed cakes, forestry wastes, food wastes, municipal wastes, and digestated residues. Such wastes generally contain fewer digestible compounds (e.g. fatty acids and sugars), and more proteins and recalcitrant lignin, which require more severe reaction conditions to extract valuable compounds. Pyrolysis is a potential inexpensive extraction option for these compounds with the needed reaction severity, easy operation, and high compatibility with diverse feedstocks. Here, pyrolysis reactions of protein- and lignin-rich biomass wastes are compared in terms of feedstock composition, degradation mechanism, and yield and quality of bio-oils. Overall, agricultural wastes, dedicated plants, seed cakes, digestates, and municipal wastes are recommended for pyrolysis in terms of higher yields and higher quality of bio-oils. Denitrogenation upgrading strategies can further improve the potential of the produced bio-oils.
Article
Charcoal from biomass is a promising alternative for fossil coal. Although its quality increases at high pyrolysis temperature, charcoal yield decreases, meaning lower economic performances of charcoal production processes. This work aims at demonstrating potential methods to increase charcoal yield while keeping its quality at satisfying levels. We suggested the recycling of bio-oil from pyrolysis process as a primary measure. In addition, we also investigated in detail the consequence of utilizing CO2 instead of N2 as reaction media under practical conditions (i.e. thick particles). An experimental investigation was carried out in a macro-thermogravimetric (macro-TG) reactor. Sample (woodchips, bio-oil, and woodchips embedded with bio-oil) was exposed to the reaction temperature either instantaneously (isothermal condition) or by slow heating (slow pyrolysis) in controlled gas flows of N2 and CO2. The results showed that char yield increases with the bio-oil recycling on wood chips at all pyrolysis temperatures (300–700 °C). By 20% of bio-oil embedding on wood chips, charcoal yield increased by 18.3% on average. The increase of charcoal yield was not only because of the increase in reactants, but also due to the synergetic effect between bio-oil and wood chips upon physical contact. Bio-oil recycling had negligible effects on the property of charcoal, such as carbon content and heating value. Although CO2 did not affect primary pyrolysis, it had effects on mass transfer processes. As a result, significantly higher char yield was obtained from pyrolysis in CO2 than in N2 by ensuring a good contact of volatiles and solid surface (i.e. usage of thick particles and slow heating). This study suggests that we can achieve high charcoal yield while maintaining the similar charcoal property by bio-oil recycling, CO2 purging, use of thick particles, and slow heating.
Article
Micro-fluidized bed (MFB) is a novel technology for engineering processing and screening application due to its good mixing, high mass/heat transfer, reduced reaction time and cost, but issues that remain unresolved are the low fluidization quality and scalability. In this review paper, fundamental and characteristic studies are reviewed to gain an understanding of the miniaturized fluidized bed system for rapid processing and screening. Subsequently, recent progresses of the MFB applications are evaluated and compared with other types of reactors from the perspective of process intensification (PI). Finally, the challenges and prospects for this technology for PI are also discussed.
Chapter
Energy derived from biomass provides a promising alternative source that reduces dependence on fossil fuels along with the emission of greenhouse gases (GHG). The production of heat, electricity, power, fuels, and various chemicals from the biomass can be achieved via thermochemical conversion technologies. This chapter summarizes the techno-economic analysis and life-cycle assessment of lignocellulosic biomass via thermochemical conversion routes such as combustion, pyrolysis, gasification, liquefaction, (hydrothermal). and co-firing. Specific indicators such as production costs, techno-economic analysis, functional units, and environmental impacts in a life-cycle analysis for different techniques were compared. Finally, the research lacunae and possible future trends in biomass conversion via thermochemical conversion techniques have been discussed, which may positively impact the future of research related to techno-economic and environmental benefits of bioenergy.
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In this study, the size of tobacco rob (TR) particle was considered as a major factor in determining the mass loss in thermogravimetric analysis (TGA) and product yield and composition at different reactor temperatures in the fixed-bed reactor. The TGA results showed that the conversion rate increased and the activation energy (ranged from 53.29 to 58.25 kJ/mol) decreased with a decrease in particle size. The experiments demonstrated that fuel gas yield (from 0.76 to 0.82 Nm³/kg at 900 °C) increased with a decrease in particle size while char and tar yield decreased. Smaller particle sizes resulted in higher H2 (25.68%) and CO (27.36%) contents. Minimizing the size of raw materials is an alternative method to improve the gas quality of TR pyrolysis. The increase of gas yield was attributed to the decomposition of char and tar vapor as temperature increased.
Article
Catalytic fast pyrolysis (CFP) has been identified as a promising pathway for the production of renewable fuels and co-products. However, continued technology development is needed to increase process efficiency and reduce process costs. This report builds upon previous research in which a bifunctional metal-acid Pt/TiO2 catalyst was utilized in a fixed-bed reactor operated with co-fed H2 to improve product yield and reduce coke generation compared to conventional CFP methods. Here, we report further process optimization, in which we achieved similar CFP oil carbon efficiency (>35%) and CFP oil oxygen content (<20 wt %) to our previous report while reducing catalyst and equipment costs by increasing time-on-stream between regenerations by 40-95% and decreasing required regeneration time by more than a factor of 2. These process improvements were achieved by conducting parameter sweeps to determine optimum conditions for CFP and regeneration with key variables including pyrolysis temperature, catalytic upgrading temperature, hydrogen partial pressure, and regeneration oxygen concentration. Coupled with comprehensive oil analyses, these data provide foundational insight into the deoxygenation and coking chemistries for CFP under realistic process conditions while also advancing the technology through applied engineering.
Article
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The article presents a review of works on mathematical modelling of biomass pyrolysis process. Models types, number of dimensions, captured phenomena, type and dimensions of the reactors and biomass particles as well as models validation methods were analysed. Particular attention was paid to descriptions of chemical reactions, which are the essence of biomass thermal decomposition simulation. The article briefly describes the most important issues related to biomass pyrolysis and provides a review of commonly used methods of modelling this process with emphasis on solutions "ready to employ" in CFD modelling. A summary of other review papers on this topic is also provided. The problem of mathematical modelling in the context of “model - an engineering tool” was also discussed. Mathematical model for an engineering applications must be prepared with consideration of necessary consensus between the calculations accuracy, calculation time, preparation efforts and analysis requirements. Therefore, in pyrolysis modelling context, the inclusion of chemical reactions and changes of heat transport conditions were considered as priority, while taking into account moisture evaporation and shrinkage of the bed should be conditioned by their actual contribution in the calculations accuracy and the other hand by their influence on the time of calculations.
Article
Solar pyrolysis shows promise as a technique to generate solar fuels in the context of future economy besides mitigating emissions. The prior experiments were mainly demonstrated in an indoor environment using a solar simulator while recent studies have been established using natural solar radiation. An integrated solar receiver-reactor is likely to be employed to generate high-temperature for the conversion of feedstocks into valuable products. Undoubtedly, parabolic trough and parabolic dish with the integration of fixed bed batch reactor are the two-common type of concentrators that has been widely used by the researcher. The effectiveness of a solar pyrolysis process depends not only on the reactor configuration but also on the process variables. Temperature is the most crucial factor that dominant product yields. The current literature is scattered, vague, and difficult to understand the configuration of the system and operating parameters that affect the yield of solar products. In order to carry out an efficient solar pyrolysis reaction, the latest design and fabrication of different modes of experimental setup is presented. Moreover, operating factors that dominate the product quantity are elaborately discussed. A critical discussion, some challenges, and its probable solutions during scale-up of a pyrolysis system are also delivered.
Article
A mechanically stirred entrainment-type feeder for fine solids has been developed which will give rates constant to +/- 5% for 1 h or more. The feeder was constructed in connection with a mini-fluidized bed flash pyrolysis project for both biomass and Canadian coals. It has been used to feed coal, sawdust and ground bark in sizes below 600 ..mu..m at rates as low as 6 g/h. Gas to solids weight ratios obtained were from about 3:1 to 1:3. The effect on feed rates of most of the operating and geometric parameters was investigated at low feed rates. A mechanism for control of the feed rate was tested and found to be satisfactory.
Article
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 also been developed. Extensive pyrolysis tests with hybrid aspen-popular sawdust (105–250 μm) 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 fed are possible at residence times of less than one second. On a conçu et employé avec succès, à l'échelle du laboratoire, une unité de pyrolyse-éclair à lit fluidisé continu; le dispositif fonctionnait à la pression atmosphérique et à des débits d'alimentation d'environ 15 g/h. On a aussi mis au point un dispositif unique d'alimentation en matières solides, capable d'assurer de faibles débits constants de biomasse. On a fait des expériences poussées de pyrolyse sur des sciures d'hybrides de peuplier-faux tremble (105—250 μm), dans le but d'étudier les effets de la température, de la granulométrie des particules, de l'atmosphère de la pyrolyse et d'un traitement préalable du bois sur les rendements en goudron, liquides organiques, gaz et matières carbonisées. Il est possible, dans les conditions optimales de pyrolyse, d'obtenir des rendements élevés en goudron, qui peuvent atteindre 65% du bois sec d'alimentation en poids pour des temps de séjour de moins d'une seconde.
Ablative Pyrolysis of Macroparticles of Biomass
  • J Diebold
Diebold, J., " Ablative Pyrolysis of Macroparticles of Biomass ", Proc. Specialists Workshop on Fast Pyrolysis of Biomass, 237-252, October, (1980), SERI/CP 622-1096.
Private communication
  • Douglas C Elliott
Elliott, Douglas C., Private communication, Pacific Northwest Laboratory, Richland, Wash., Aug. (1983).