A detailed kinetic model for the hydrothermal decomposition process of sewage sludge

Yin, Fengjun; Chen, Hongzhen; Xu, Guihua; Wang, Guangwei; Xu, Yuan

doi:10.1016/j.biortech.2015.09.033

Cited by 46 publications

(14 citation statements)

References 21 publications

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“…Bougrier et al (2008) and Donoso-Bravo et al (2011) concluded that volatile fatty acids are produced by lipid degradation instead of by protein decomposition. Yin et al (2015) studied the time and temperature dependence of soluble proteins and carbohydrates and ammoniacal nitrogen, and found that at 220 -300ºC, soluble proteins and carbohydrates went through a maximum with the reaction time, and that the higher the temperature, the lower the time at which the maximum appear. At this point, it is important to stress that, although information about the composition of soluble biopolymer during the sludge TH is available, there is no studies dealing with the properties of these biopolymers, such as their molecular weight size.…”

Section: Introductionmentioning

confidence: 99%

Sludge hydrothermal treatments. Oxidising atmosphere effects on biopolymers and physical properties

Urrea

García

Collado

et al. 2018

Journal of Environmental Management

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In this work, the role of an oxidising atmosphere during the hydrothermal treatment of an activated sludge at 160 °C and 40 bar, was determined. The composition and molecular weight sizes of the soluble biopolymers generated during the sludge treatment in presence (wet oxidation "WO") or absence (thermal hydrolysis "TH") of oxygen were compared. Likewise, the characteristics of organic material, settleability, colour and pH of the treated sludge during both treatments were analysed. The thermal treatment in presence of oxygen provided better results in terms of solubilisation, settleability and mineralisation. WO initially favoured a more intense cellular lysis, causing a higher degree of solubilisation than that achieved by TH. Either in presence or absence of oxygen, thermal treatments caused a marked worsening of the settleability of the sludge. However, the degradation of biopolymers during WO led subsequently to an improvement of the settleability properties for longer reaction times. Both treatments caused a fast solubilisation of biopolymers at the beginning by effect of the release of extracellular and intracellular material from sludge. Subsequently, the presence of oxygen produced a significant decrease in the concentration of those biopolymers. In contrast, the proteins were the only one biopolymer that was degraded during TH.

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Section: Introductionmentioning

confidence: 99%

Sludge hydrothermal treatments. Oxidising atmosphere effects on biopolymers and physical properties

Urrea

García

Collado

et al. 2018

Journal of Environmental Management

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“…The NH 4 -N concentration and the NH 4 -N release follow the discussed trend of a higher influence of the reaction time at higher temperatures. Since for all experiments the concentration of TN in the liquid phase remained relatively consistent at 2254 ± 84 mg/L, lower hydrothermal conditions favor hydrolysis of the solid phase nitrogen, while more intense hydrothermal conditions lead to the decomposition of dissolved nitrogen into lower molecular products with the release of NH 4 -N [42]. Dissolved organic nitrogen compounds are degraded into NH 4 -N, for example, as a result of deamination.…”

Section: Surface Analysis Of Process Water Load (Raw Sewage Sludge 1)mentioning

confidence: 92%

Optimizing the Hydrothermal Carbonization of Sewage Sludge—Response Surface Methodology and the Effect of Volatile Solids

Blach

Engelhart

2021

Water

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This study focuses on identifying the optimum conditions of sewage sludge hydrothermal carbonization by Box–Behnken Design and on the effects of volatile solids on heating value and on process water load. To get insight into the solid and process water characteristics, we applied the Box–Behnken Design on the hydrothermal reaction temperature (190, 220, 250 °C), reaction time (0.5, 2.25, 4 h) and pH (3.9, 5, 6.1). The response surface of the liquid phase revealed decreasing dissolved organic carbon (DOC) concentrations with increasing temperature from 9446 mg/L (190 °C) to 7402 mg/L (250 °C) at 4 h reaction time. For the same hydrothermal conditions, NH4-N concentration increased from 754 to 1230 mg/L. Reaction temperature was identified as the most important process parameter, whereas reaction time and pH had only minor effects. Moreover, linear coefficients of the models were more decisive than the interrelation and quadratic coefficients. Volatile solids (VS) of the feedstock were found to significantly influence both the load of the process water and the change in heating value of the hydrochars. Process water load increased steadily with higher VS. The heating value only increased with more than around 65–80% VS in feedstock.

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“…They obtained values in the ranges of 70.4-77.8 kJ mol −1 and 4.0 × 10 6 -1.5 × 10 7 min −1 for the activation energy and pre-exponential factor, respectively. Still regarding sewage sludge, Yin et al [66] developed a firstorder model based on the decomposition of macromolecules and low molecular weight constituents. The reaction scheme includes two stages: a first decomposition of the biomass into its primary constituents (proteins and saccharides, present inside microorganism and the extracellular polymeric substances of the sludge) and their degradation in water into ammonia, acetic acid, and gaseous products.…”

Section: Pseudo-first-order Reaction Kinetics Modelsmentioning

confidence: 99%

Hydrothermal Carbonization of Organic Waste and Biomass: A Review on Process, Reactor, and Plant Modeling

Ischia

Fiori

2020

Waste Biomass Valor

127

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Hydrothermal carbonization (HTC) is an emerging path to give a new life to organic waste and residual biomass. Fulfilling the principles of the circular economy, through HTC “unpleasant” organics can be transformed into useful materials and possibly energy carriers. The potential applications of HTC are tremendous and the recent literature is full of investigations. In this context, models capable to predict, simulate and optimize the HTC process, reactors, and plants are engineering tools that can significantly shift HTC research towards innovation by boosting the development of novel enterprises based on HTC technology. This review paper addresses such key-issue: where do we stand regarding the development of these tools? The literature presents many and simplified models to describe the reaction kinetics, some dealing with the process simulation, while few focused on the heart of an HTC system, the reactor. Statistical investigations and some life cycle assessment analyses also appear in the current state of the art. This work examines and analyzes these predicting tools, highlighting their potentialities and limits. Overall, the current models suffer from many aspects, from the lack of data to the intrinsic complexity of HTC reactions and HTC systems. Therefore, the emphasis is given to what is still necessary to make the HTC process duly simulated and therefore implementable on an industrial scale with sufficient predictive margins. Graphic Abstract

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A detailed kinetic model for the hydrothermal decomposition process of sewage sludge

Cited by 46 publications

References 21 publications

Sludge hydrothermal treatments. Oxidising atmosphere effects on biopolymers and physical properties

Sludge hydrothermal treatments. Oxidising atmosphere effects on biopolymers and physical properties

Optimizing the Hydrothermal Carbonization of Sewage Sludge—Response Surface Methodology and the Effect of Volatile Solids

Hydrothermal Carbonization of Organic Waste and Biomass: A Review on Process, Reactor, and Plant Modeling

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