Thermochemical conversion of sewage sludge: A critical review

Quan, Cui; Kamran, Kamran; Williams, Paul T.

doi:10.1016/j.pecs.2020.100843

Cited by 476 publications

(166 citation statements)

References 281 publications

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“…There are a series of metal catalysts that are proved to be efficient in the deoxygenation of bio-oil derived from sludge or other polluted feedstocks; however, catalysts are usually based on metals (Ni, Co, Mo, Zn, Fe, Cu, Cs, Mg, and noble metal-based catalysts) [73,74] which are highly sensitive to the presence of the impurities. Therefore, the stability problem is an important issue and efficient solutions are highly demanded [75]. One of the strategies allowing for mitigation of the negative effect of those impurities present in highly polluted feedstock such as sludge is to blend it with other non-polluted biomass before high-temperature treatment [76].…”

Section: Contamination Of Bio-oil During Pyrolysismentioning

confidence: 99%

Catalyst Stability—Bottleneck of Efficient Catalytic Pyrolysis

Grams

Ruppert

2021

Catalysts

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The pyrolysis of lignocellulosic biomass is one of the most promising methods of alternative fuels production. However, due to the low selectivity of this process, the quality of the obtained bio-oil is usually not satisfactory and does not allow for its direct use as an engine fuel. Therefore, there is a need to apply catalysts able to upgrade the composition of the mixture of pyrolysis products. Unfortunately, despite the increase in the efficiency of the thermal decomposition of biomass, the catalysts undergo relatively fast deactivation and their stability can be considered a bottleneck of efficient pyrolysis of lignocellulosic feedstock. Therefore, solving the problem of catalyst stability is extremely important. Taking that into account, we presented, in this review, the most important reasons for catalyst deactivation, including coke formation, sintering, hydrothermal instability, and catalyst poisoning. Moreover, we discussed the progress in the development of methods leading to an increase in the stability of the catalysts of lignocellulosic biomass pyrolysis and strengthening their resistance to deactivation.

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Section: Contamination Of Bio-oil During Pyrolysismentioning

confidence: 99%

Catalyst Stability—Bottleneck of Efficient Catalytic Pyrolysis

Grams

Ruppert

2021

Catalysts

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“…Adar et al 4 used supercritical water gasification technology to treat sludge to explore the relationship between temperature and gasification efficiency, which decomposed the organic matter in sludge to produce H 2 and CH 4 under the determined optimal experimental conditions. OS contains a large number of petroleum substances, 5 and organic content is higher compared with biomass and sewage sludge, which is very suitable for gasification. Gao et al 6 simulated the coupling process of pyrolysis and gasification of OS in a rotary kiln and found that the yield of gaseous products CH 4 , C 2 H 4 , C 2 H 6 , CO, and H 2 increased rapidly with the increase of temperature.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on kinetic characteristics of oil sludge gasification

Chu

Gong²,

Wang

et al. 2021

Asia-Pacific J Chem Eng

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Oil sludge (OS) is a typical dangerous waste in petroleum industry, which also contains abundant energy. The purpose of this study was to recover resources from OS gasification. To figure out the gasification process, a thermal analyzer was used to carry out OS gasification experiments under steam/nitrogen atmosphere with different heating rates. Results showed that the OS gasification reaction could be divided into five stages: free water volatilization, the escape of light components, the cracking of heavy components and steam reforming, the charring process and water gas shift (WGS) reactions, and inorganic mineral decomposition. The activation energy (E), pre‐exponential factor (A), enthalpy change (ΔH), Gibbs free energy change (ΔG), and entropy change (ΔS) of three main reaction stages (Stages 2–4) were analyzed through kinetic and thermodynamic analysis. From Stage 2 to Stage 4, E, ΔH, and ΔS decreased from 118.80 kJ·mol−1, 113.92 kJ·mol−1, and −4.09 J·(K mol)−1 to 13.19 kJ·mol−1, 5.92 kJ·mol−1, and −234.06 J·(K mol)−1, respectively. Nevertheless, ΔG increased from 116.01 to 210.04 kJ·mol−1. From these parameters, it could be found that the decrease of E was beneficial to the reaction. However, the values of ΔG were always positive and the reaction could not happen spontaneously.

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“…The thermogravimetric analysis (TGA) has been used widely to provide excellent information about the pyrolysis kinetics behaviour of waste plastics [3][4][5][6] and other types of raw materials such as biomass, sludge and coal. [7][8][9][10] The thermal degradation mechanism of waste plastics involves many complex reactions such as radical recombination, hydrogen abstraction, chain scission and carbon hydrogen bond scission. 11 Many reports in the literature have been published about the thermal degradation kinetics of polyolefin.…”

Section: Introductionmentioning

confidence: 99%

Thermo‐catalytic pyrolysis of wastes using bimetal‐modified ZSM ‐5 catalyst: investigation of the reaction kinetic parameters

et al. 2021

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The decomposition of waste polymers and the main reaction kinetic parameters of the pyrolysis have been discussed based on thermogravimetric analysis (TGA) using Me/Ni/ZSM-5 catalysts (Me = Ca, Ce, La, Mg, Mn). Mainly, the effect of the raw materials (polyolefin, polyethylene terephthalate) and catalyst presence to the weight loss were investigated. The tested catalysts can effectively reduce the activation energies of the waste pyrolysis. However, different tendencies were found in case of different raw materials. Based on results, the La/Ni/ZSM-5 catalyst was further investigated using raw material: catalyst ratio of 2:1, 1:1, 1:2 and 1:3 by both TG instrument and tubular furnace reactor at 500 C and 900 C. Mainly, the gas composition and the syngas yield were investigated. The lowest activation energy and the highest yield of the syngas (92.3 mmol/g raw material using pyrolysis-reforming 900 C) were found in case of raw material:catalyst ratio of 2:1.

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Thermochemical conversion of sewage sludge: A critical review

Cited by 476 publications

References 281 publications

Catalyst Stability—Bottleneck of Efficient Catalytic Pyrolysis

Catalyst Stability—Bottleneck of Efficient Catalytic Pyrolysis

Experimental study on kinetic characteristics of oil sludge gasification

Thermo‐catalytic pyrolysis of wastes using bimetal‐modified ZSM ‐5 catalyst: investigation of the reaction kinetic parameters

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