Kinetic studies of overlapping pyrolysis reactions in industrial waste activated sludge

Jiang, Zhenpeng

doi:10.1016/j.biortech.2009.03.002

Cited by 39 publications

(12 citation statements)

References 15 publications

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“…It can be seen from the DTG curve that there is a maximum mass loss peak for the four samples at this stage, corresponding to 248.45°C, 216.39°C, 197.89°C, and 223.61°C (taking 10°C/min as an example), which means the sample decomposition rate reaches the highest. The mass loss at this stage is mainly caused by the decomposition of large molecular weight organics into small molecular weight organics [25]. The mass loss of the four samples at this stage reached 21%, 31%, 30% and 33% respectively.…”

Section: Thermogravimetric Analysismentioning

confidence: 91%

Thermodynamic model and kinetic compensation effect of oil sludge pyrolysis based on thermogravimetric analysis

Liu

Xiang

Mu³

et al. 2022

Therm sci

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Oil sludge (OS) is an organic solid waste in the petrochemical industry and improper treatment of OS will cause environmental pollution. Pyrolysis is an effective way to realize its resource reuse. In order to understand the pyrolysis behavior and thermodynamic characteristics of OS, four OS samples from storage tanks were used as the research object, and pyrolysis experiments were carried out at heating rates of 5, 10, and 15?/min under a nitrogen atmosphere. The kinetic parameters of pyrolysis of OS are calculated by three equal conversion methods (Friedman method (FR), Flynn-Wall-Ozawa method (FWO) and Distributed activation energy model (DAEM)), and the most possible thermodynamic models for the main pyrolysis phase were analyzed and discussed by introducing the Malek method. The results show: High heating rate can promote the pyrolysis of OS; In the pyrolysis stage, the apparent activation energy increases with the increase of the conversion rate. The apparent activation energy calculated by the FR method is more reliable. The average apparent activation energies of the four OS are 221.23, 84.71, 94.67 and 116.56 kJ/mol, respectively. The apparent activation energy and the pre-exponential factor are positively correlated, indicating that there is a kinetic compensation effect in the pyrolysis process. The thermodynamic models of the four OS samples are all three-dimensional diffusion models, but their integral functions are different. The research results can provide theoretical support for the industrialization, harmlessness and resource utilization of OS pyrolysis.

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Section: Thermogravimetric Analysismentioning

confidence: 91%

Thermodynamic model and kinetic compensation effect of oil sludge pyrolysis based on thermogravimetric analysis

Liu

Xiang

Mu³

et al. 2022

Therm sci

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“…The second one was the carbonation reaction. The main groups in OS included proteins, fats, and oils, 33,34 which were easy to break down during the thermal process.…”

Section: Methodsmentioning

confidence: 99%

Experimental Study on Pyrolysis Characteristics of Oil Sludge with a Tube Furnace Reactor

Gong

Wang

et al. 2017

Energy Fuels

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Oil sludge (OS) pyrolysis was conducted with a tube furnace reactor. Production distributions and compositions were investigated under different conditions of pyrolysis temperature, heating mode, and atmosphere (N2/CO2). Little change was detected with the product yields of char, oil, and gas when the final temperature exceeded 600 °C. Compared with slow pyrolysis, oil and char yields decreased and gas yield increased in fast pyrolysis. CO2 could promote OS pyrolysis, resulting in a reduction of char yield. SEM images showed that the surface of OS was smooth with a dense texture while the surface of OS char was rough with a well-developed pore structure that formed after pyrolysis. Simulated distillation results showed that light fractions from OS pyrolysis were more than 30% higher than those of oil from OS extraction. With the increase of pyrolysis temperature, light fractions (gasoline, diesel, and jet fuel) in pyrolysis oil decreased. During fast pyrolysis, the heavy fractions produced can be cracked into light fractions. The content of light fractions was 46% compared with 34% for oil from slow pyrolysis. It did not differ much with the oil product distributions from pyrolysis in inert (N2) and CO2 atmosphere. The yields of C4–6 and C6 were higher than those of CH4 in slow pyrolysis between 500 and 700 °C. Fast pyrolysis and CO2 atmosphere favored the conversion of stable macromolecules to short chain methyl compounds, resulting in a higher CH4 yield.

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“…No well-defined sharp peaks can be seen in Figure 3 indicating that the devolatilization of sludge probably involves more than one reaction. The rate of mass loss peaks were appeared to be overlapping and asymmetrical, which implied that several substances in the sludge may decompose together at nearly the same temperature range (Yang and Jiang, 2009). This phenomenon can be associated with the sludge components which mostly consisted of hemicellulose, cellulose, lignin, and activated sludge microbes.…”

Section: The Sludge-coal Pyrolysis Characteristicsmentioning

confidence: 99%

Non-Isothermal Pyrolysis Kinetic Studies of Kraft Pulp Mill Sludge and Its Blending with Coal Powder

et al. 2019

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Non-isothermal pyrolysis of kraft pulp mill sludge and coal has been investigated. Blending sludge with coal resulted time increase to complete the pyrolysis. This phenomenon indicated that volatile matter in coal was more difficult to be degraded. Sludge pyrolysis at 10, 15, and 20°C/min remained residual mass fraction of 64.6% w/w, 62.4% w/w, and 64.4% w/w, respectively. Coal addition into sludge had reduced char yield. Char yield decreasing was due to lower content of coal ash compared to sludge ash.Sludge lost most of its mass was between 200°C and 500°C, and its peak was at 280°C. -It was slow at >500°C. Wide range of coal degradation temperature indicated that coal may contain components having a wide range temperature degradation, such as lignin. Based on the curve of mass loss rate of reaction, there were three peaks which indicates three reaction mechanisms of sludge-coal pyrolysis. All peaks followed the mechanism of frst order reaction. First peak was likely to occur due to decomposition of hemicellulose and other highly volatile components. Second and third were associate with cellulose and lignin, respectively. The high thermal stability properties lead to a slow degradation of lignin, and its mass loss occurred in the a very wide of temperature range (160-900°C). Studi Kinetika Pirolisis Non-Isotermal Lumpur Industri Pulp Kraft dan Campurannya dengan Serbuk BatubaraPirolisis non-isotermal lumpur industri pulp kraft dan campurannya dengan serbuk batubara telah diselidiki. Pencampuran lumpur dengan batubara menghasilkan peningkatan waktu untuk menyelesaikan pirolisis. Fenomena ini menunjukkan bahwa zat volatil dalam batubara lebih sulit terdegradasi. Pirolisis lumpur pada 10, 15, dan 20°C/menit menghasilkan fraksi massa residu masing-masing 64,6% b/b, 62,4% b/b, dan 64,4% b/b. Penambahan batubara ke dalam lumpur mengurangi hasil arang. Penurunan hasil arang disebabkan oleh kandungan abu batubara yang lebih rendah dibandingkan dengan abu lumpur. Lumpur kehilangan sebagian besar massanya antara 200°C dan 500°C, dan mencapai puncaknya pada 280°C. Kehilangan massa melambat pada suhu >500°C. Rentang suhu yang lebar pada degradasi batubara menunjukkan bahwa batubara mengandung komponen yang memiliki suhu degradasi luas, seperti lignin. Berdasarkan kurva laju kehilangan massa, terdapat tiga puncak reaksi yang menunjukkan tiga mekanisme reaksi pirolisis lumpur-batubara. Semua puncak tersebut mengikuti mekanisme reaksi orde pertama. Puncak pertama kemungkinan terjadi karena dekomposisi hemiselulosa, dan komponen-komponen lain yang sangat mudah menguap. Puncak kedua dan ketiga masing-masing berhubungan dengan selulosa dan lignin. Sifat stabilitas termal yang tinggi menyebabkan degradasi lignin yang lambat, dan kehilangan massa terjadi dalam kisaran suhu yang sangat luas (160-900°C).

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Kinetic studies of overlapping pyrolysis reactions in industrial waste activated sludge

Cited by 39 publications

References 15 publications

Thermodynamic model and kinetic compensation effect of oil sludge pyrolysis based on thermogravimetric analysis

Thermodynamic model and kinetic compensation effect of oil sludge pyrolysis based on thermogravimetric analysis

Experimental Study on Pyrolysis Characteristics of Oil Sludge with a Tube Furnace Reactor

Non-Isothermal Pyrolysis Kinetic Studies of Kraft Pulp Mill Sludge and Its Blending with Coal Powder

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