•Comparative analysis of pyrolysis oils obtained from organic and plastic wastes.•Waste HDPE provided the highest yield of pyrolysis oil (61.29 %) at 525 °C.•Analysis of oils using GC–MS showed the ...presence of 12 chemical functional groups.•Organic waste-derived oils contain phenolic, aromatic, and oxygenated compounds.•Waste HDPE-derived oil meets most of the criteria for being an engine fuel.
The objective of this study is to assess the suitability of pyrolysis oils produced from organic and plastic wastes for engine application. The assessment was performed by comparing the properties of the obtained pyrolysis oils with those of standard engine fuel. A fast pyrolysis process with an auger reactor was used to convert organic wastes such as beauty leaf fruit husk (BLFH), macadamia nutshell (MNS), and municipal green waste (MGW), and plastic waste such as waste high-density polythene (HDPE) into oil. Prior to pyrolysis experiments, all the wastes were characterized using a thermogravimetric and a CHNS analyser to perform proximate and ultimate analyses. The experiments were performed using varied temperatures ranging from 400 °C to 550 °C at intervals of 25 °C, a 3-minute residence time and 2-mm feedstock particle size. The maximum yield of pyrolysis oil was obtained at 475 °C for BLFH (42.75 %), at 500 °C for MNS (45.09 %) and MGW (44.72 %) and at 525 °C for HDPE (61.29 %). The chemical and physical properties of the pyrolysis oils were analysed using Fourier transform infrared spectroscopy (FTIR), Gas chromatography–mass spectrometry (GC–MS), elemental and physicochemical properties analysis. The characterisation results reveal that the pyrolysis oils obtained from BLFH, MNS and MGW are enriched with phenolic, aromatic, and oxygenated compounds and oil obtained from HDPE contains mostly hydrocarbons and aromatics. The BLFH, MNS and MGW derived oils have higher viscosity and density and lower calorific value compared to that of HDPE derived oil. Due to these features, the oils obtained from organic wastes are not suitable for engine application without further refinement. HDPE derived oil, on the other hand, meets most of the criteria to be an engine fuel. However, a firm conclusion cannot be drawn until this oil has been tested in an engine.
•Volatiles-interaction affected the yield and composition distribution of bio-oil.•Gas yield increased but liquid yield decreased after volatiles-interaction.•CH4 increased above 600 °C in the ...presence of lignin volatiles.•Hemicellulose volatiles increased decomposition of cellulose volatiles.•Cellulose-derived sugars was promoted by hemicellulose or lignin volatiles.
Secondary reactions, including those caused by the interaction of volatiles, are unavoidable during biomass pyrolysis. This study investigated the interactions of the volatiles from cellulose, hemicellulose, and lignin in a two-stage fixed bed reactor without a pre-mixed feedstock. The yield distribution of the products and gases, and the composition of liquids were all affected by the interaction of the volatiles. The interactions increased the gas yield but inhibited the liquid yield. However, when temperature increased, the interactions weakened in the presence of cellulose but increased when hemicellulose and lignin were used. Independent of feedstock, the interactions also generated CO2 and H2 at 400–700 °C and inhibited the generation of CH4 and phenols below 500 °C and 400–700 °C, respectively. However, several feedstock-dependent interactions were also observed: 1) CH4 generation increased at temperatures above 600 °C in the presence of lignin volatiles; 2) both hemicellulose and lignin volatiles resulted in significant amounts of cellulose-derived sugars at temperatures above 500 °C; and 3) hemicellulose volatiles increased decomposition of cellulose volatiles, while the latter inhibited the decomposition of lignin volatiles, when the temperature was below 500 °C.
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•Low-temperature pyrolysis treatment was used to destroy caking property of coal.•In situ morphological changes in liquid crystals were recorded.•A microscopic description of the ...factors affecting caking property is provided.•Combined effects of AlHsc6-25, ArHsr2-4, and fa control caking property of coal.
We proposed a low-temperature pyrolysis treatment (LTPT) to destroy the caking properties of a fat coal (FC) and a 1/3 coking coal (CC). To reveal the factors affecting caking property, the changes in the chemical properties of pyrolysis products were analyzed using Fourier transform infrared spectrometry, X-ray diffractometer, and gas chromatograph/mass spectrometer (GC/MS). The in situ morphological changes in the liquid crystals produced by the two coal samples during LTPT process were also recorded using a hot-stage microscope. Of particular interest was a microscopic description of the factors affecting caking property. The results showed that the caking index (G) of FC decreased with increasing temperature and became zero at about 500 °C. Hot-stage microscope showed FC produced liquid crystals at 395 °C, the size of which continuously increased, with an accompanying of the generation of new liquid crystals. GC/MS showed large amounts of aliphatic hydrocarbons with the number of carbon of 6–25 (AlHsc6-25) and aromatic hydrocarbons with 2–4 rings (ArHsr2-4) were removed from FC. The aromaticity (fa) of FC increased only substantially from 395 to 494 °C. Meanwhile, the G of FC decreased only significantly in the same temperature range. A similar result was observed for CC. The removal of AlHsc6-25 leads to insufficient supply of hydrogen radicals; therefore, relatively high-molecular weight aromatics quickly cross-linked into semicoke. Additionally, the evolution of ArHsr2-4 and the increase in fa restrain the originating of crystal liquids. As a result, the loss of G was observed.
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•Co-pyrolysis mechanism of lignocellulosic biomass and amino acids was studied.•Glu formed 52% pyrrolidinone, and Asp generated 75% maleimide with dehydration.•Co-pyrolysis decreased ...cracking temperature, and promoted CO2, CO, NH3 release.•Co-pyrolysis decreased N-species, while increased phenols, O-species for bio-oil.•Main reactions were Maillard reaction, ketonization, deamination, decarboxylation.
Co-pyrolysis of lignocellulosic biomass and microalgae could greatly improve bio-oil quality. In order to understand the interaction, nitrogen transformation mechanism, and better use lignocellulosic biomass and microalgae, co-pyrolysis of lignocellulosic biomass (bamboo waste (Ba)) and amino acids (glutamic acid (Glu) and aspartic acid (Asp)) was performed by TG-FTIR and Py-GC/MS technique. Results showed that individual pyrolysis of Glu and Asp formed 52% pyrrolidinone and 75% maleimide through intramolecular dehydration reactions, respectively, with the releasing of CO2, CO and NH3. Besides, co-pyrolysis of Ba with Glu and Asp decreased the biomass decomposition temperature largely. Furthermore, co-pyrolysis greatly increased the yield of CO2 and NH3, and promoted the formation of phenols, O-containing species (but oxygen yield decreased), while inhibited the generation of N-species (decreased about 50%) in bio-oil, through strong Maillard reaction, ketonization, deamination, and decarboxylation reactions. At last, the possible reaction pathways of co-pyrolysis of lignocellulosic biomass and amino acids were proposed. In conclusion, co-pyrolysis of lignocellulosic biomass and amino acids could significantly improve the quality of bio-oil, and effectively control the nitrogen transformation into bio-oil.
•The pyrolysis kinetics of superfine pulverized coal are obtained.•Different models of Coat-Redfern, Starink, and simplified DAEM are successfully employed.•A novel application of piecewise ...Coat-Redfern based on the tangent-bisecting method is developed.•The kinetic compensation effect is established, and its mechanistic implications are discussed.
Coal pyrolysis is a complex process with multiple characterized kinetics that play a crucial role in understanding the devolatilization mechanisms, predicting the products distribution, and designing the reactors, etc. However, there is little knowledge about the pyrolysis kinetics of superfine pulverized coal. In this paper, typical thermogravimetric experiments at low heating rates are performed, which can identify individual species and provide reliable kinetic data. Then, three classical kinetic models are combined to analyze the superfine coal pyrolysis process, including Coats-Redfern (model-fitting type), Starink (model-free group) and distributed activation energy model (DAEM, continuous distribution category). Firstly, a five-reaction decomposition regime is identified through a tangent-bisecting method. Then, a novel application of piecewise Coats-Redfern model based on the tangent-bisecting method is developed, which shows that the coal particle size has a notable impact on the pyrolysis kinetics. Superfine pulverized coal can promote the primary pyrolysis process while inhibit the secondary reactions. Secondly, the Starink model is employed, and the arithmetic mean activation energy increases initially with increasing the particle size, and then declines, attributing to the contradictory effect of particle size. Finally, The distribution function f(E) is deduced based on the Miura-Maki DAEM, which spreads broadly with a single sharp peak. Additionally, the kinetic compensation effect (KCE) of k0 and E is observed for the Miura-Maki DAEM, which can be utilized to establish certain mechanistic implications. The findings from this work give a better interpretation on the kinetic parameters, and provide us a new perspective to understand the effect of particle size on the coal pyrolysis kinetics.
Bu çalışma kapsamında ayçiçeği küspesinin hızlı pirolizinin katalizörsüz koşulda ve klinoptilolit katalizörü
kullanılarak yapılmasının, elde edilen ürün verimleri ve ürün özellikleri üzerine etkileri ...araştırılmıştır. Araştırma
kapsamında hammadde olarak kullanılan ayçiçeği küspesinin nem içeriği %5.92, kül içeriği %6.08, uçucu madde
yüzdesi %71.30 ve sabit karbon yüzdesi %16.70 olarak belirlenmiştir. Elemental analiz sonuçlarına göre C, H, N
ve S yüzdeleri sırasıyla %42.06, %6.26, %6.93, %0.00 olarak saptanmıştır. Isıl değeri ise 17.13 MJ/kg olarak
hesaplanmıştır. Araştırma kapsamında ilk olarak, ısıtma hızı (100, 200, 300 ℃/dk), piroliz sıcaklığı (400, 500,
600℃) ve katalizör yüzdelerinin (%5, %10, %15) ürün verimleri (biyokömür, biyoyağ ve piroliz gazı) üzerine
etkileri incelenmiştir. Ayçiçeği küspesinin hızlı piroliz işleminde klinoptilolit katalizörü eklenmesiyle yapılan
denemelerde, katalizörün katı ürün verimini önemli düzeyde değiştirmediği, sıvı ürün verimini oldukça düşürdüğü
ve gaz ürün verimini artırdığı belirlenmiştir. Biyokömür örneklerinde en yüksek üst ısıl değer, katalizörsüz koşulda
500 ℃ sıcaklık ve 300 ℃/dk ısınma hızında 22.95 MJ/kg olarak elde edilmiştir. Biyokömür örneklerinin
mikroskobik yapısı incelendiğinde (SEM analizi) hammaddeye göre gözenekliliğin arttığı anlaşılmıştır.
Katalizörsüz koşulda elde edilmiş olan piroliz gazı örneklerinin alt ısıl değerlerinin katalizörlü koşulda elde edilen
örneklerinkine göre daha yüksek olduğu belirlenmiştir. Elde edilen gaz örneklerinde en yüksek alt ısıl değer 400 ℃
sıcaklıkta, 100 ℃/dk ısınma hızında 29.05 MJ/Nm³ olarak elde edilmiştir. Ayçiçeği küspesinin farklı sıcaklıklarda,
farklı ısıtma hızlarında katalizörlü ve katalizörsüz koşulda pirolizi ile elde edilmiş olan biyoyağ örnekleri GC-MS
yöntemiyle incelenmiş, özellikle fenol bileşiklerinin (Phenol, Phenol, 2-methoxy-) hemen her numunede olduğu
saptanmıştır. Ayrıca Pyrazine-methyl, Pyrazine 2,6-dimethyl- (CAS) 2,6-Dimethylpyrazine gibi aromatik
bileşiklerde tespit edilmiştir.
Alternative fuels for diesel engines have become vital due to increase in energy expenditure, stringent norms of emission, depletion of fossil fuels and fluctuating cost of the petroleum products in ...india. To overcfome this problem, it is very important to find alternative fuels. The main focus of this review is to shed light on the importance of tyre pyrolysis oil as an alternative fuel for diesel engines. In this context, tyre pyrolysis oil has recently been receiving renewed interest. In this review, the pyrolysis mechanism, pyrolysis reactors, their product yield, characteristic analysis of tyre such as proximate analysis, elemental analysis and pyrolysis process are discussed. Pyrolysis of scrap tyre starts at 250°C and gets completed at 550°C. The presence of a catalyst produces lighter oil with drastic increase in the concentration of single ring aromatics. Engine performance, emissions and combustion parameters, such as the heat release rate and maximum rate of pressure rise, when engines are operated on a tyre pyrolysis oil were also discussed. NO(x), HC, CO, and smoke emissions were found to be higher at higher loads due to the high aromatic content and longer ignition delay. The ignition delays were longer than those with DF. It is concluded that it is possible to use tyre pyrolysis oil in diesel engines as an alternate fuel.
The waste tire pyrolysis oil (WTPO) is getting more and more attention because of its tremendous potential. But its application is limited by the higher content of impurities and the poor fuel ...performance. This paper is a review of components, properties and the utilization of WTPO, to supply some novel development pathways for it. This oil mainly consisted of alkanes and aromatic hydrocarbons, while some of the impurities such as sulfide, nitride and polyaromatic hydrocarbons (PAH) were also contained in the WTPO. Besides, this oil owns poor fuel properties such as low cetane number, low flash point and high density. Blending with diesel and cleaner production (contains desulfurization and denitrification) can reduce the pollutant emissions and enhance the fuel properties of WTPO. Additionally, it is necessary to enhance the value of WTPO to increase the economy of pyrolysis. The separation and purification of limonene and the fabrication of high-quality carbon materials and pyrolysis bitumen can be regard as the high-value utilization of WTPO. In terms of techno-economic and environmental, WTPO will become a popular subject for researchers. The integrated refinery concept of WTPO deserves more attention.
•The components and fuel properties of the WTPO have been summarized.•Blending with standard oil can be used to enhance the performance of WTPO and reduce the emissions.•The research of HDS and NHDS of WTPO have been reviewed.•The high-value utilization of WTPO has been extensively reviewed.
Flash pyrolysis of biomass: a review of recent advances Ighalo, Joshua O.; Iwuchukwu, Felicitas U.; Eyankware, Oghenegare E. ...
Clean technologies and environmental policy,
10/2022, Letnik:
24, Številka:
8
Journal Article
Recenzirano
To assuage global consumer demand for energy, there is a need for increased biofuel production. Flash pyrolysis is an important technique for biomass conversion into eco-friendly biofuels. This ...review discusses the research progress and key findings made over the years on the flash pyrolysis of biomass. Flash pyrolysis oil yields can be as high as 60–75 wt% at optimised conditions. For the process to be effective, temperature, heating rate and residence time would be within the range of 450–600 °C,
10
3
-
10
4
°C/s and < 1 s. Flash pyrolysis oil is characterised by high water content (usually > 15 wt%). The main pyrolysis products of lignin part biomass are phenols. The phenolic part includes phenols, hydroxylphenols, meothoxyphenols, dimethoxyphenols. Flash pyrolysis products of biomass (as with other pyrolysis types) must be upgraded before use. They are unstable, re-polymerised and are not miscible with hydrocarbons. The future of the technology is promising as products obtained can serve as better feedstock for other re-refining processes (compared to other pyrolysis process types). Furthermore, it is faster and can handle higher feedstock volumes at similar reactor volumes and process intricacies. Due to the advantages of product yield, it is an important technology that should be explored for energy conversion of biomass and can also serve as a solid waste management technique.
Graphical abstract
Co-pyrolysis of sludge and biomass was conducted to produce biochar with heavy metals solidification. The synergistic coupling mechanism and the surface functional groups and pore structure ...characteristics of co-pyrolytic biochar were studied. The solidification characteristics and mechanism of heavy metals were also investigated. Biomass composition in the co-pyrolysis system provided energy, solidified heavy metals and improved product quality. Compared with the weighted calculated value of two individual materials, the secondary decomposition process of co-pyrolysis was prolonged by approximately 80 °C and enhanced by 29%. OH bond, CH bond, and CO bond of co-pyrolytic biochar obtained at 500 °C increased significantly, and the carbon network structure and skeleton were enhanced, and the specific surface area increased by 102.8%, comparing with that of sludge biochar. The solidification effect of Cu and Cd in co-pyrolytic biochar was 29% and 50% higher than that in sludge biochar, respectively. The leaching rates of Cu and Cd in co-pyrolytic biochar were only 38.22% and 39.54% of that from sludge biochar. This study demonstrated that high-quality biochar with low heavy metal risk can be obtained by co-pyrolysis technology, which provides a potential way for the comprehensive utilization of industrial sludge and biomass.
•Co-pyrolysis of industrial sludge and biomass for biochar production was conducted.•Synergetic mechanism of industrial sludge and rice straw co-pyrolysis was studied.•Co-pyrolytic biochar exhibited more developed pore structure and functional groups.•Addition of biomass enhanced solidification of heavy metals in co-pyrolytic biochar.
