Response surface optimization of co-hydrothermal carbonation parameters of municipal sludge and enteromorpha
Journal Title: Energy Environmental Protection - Year 2024, Vol 38, Issue 2
Abstract
The increasing amount of municipal sludge poses a serious threat to the environment. Traditional treatment methods still face various challenges in terms of harmlessness and resource utilization. Hydrothermal carbonization is considered an effective method for treating municipal sludge, but its low carbon and high ash characteristics limit the application of hydrochar as a fuel. To address this issue, the co-hydrothermal carbonization of municipal sludge and enteromorpha (a high-carbon and low-ash waste biomass) is proposed as a potential solution. In this study, co-hydrothermal carbonization experiments of municipal sludge and enteromorpha were conducted under various reaction conditions, including temperatures ranging from 160 to 280 ℃, residence times ranging from 30 to 150 minutes, and municipal sludge proportions ranging from 0 to 100%. The impacts of these process parameters on energy recovery efficiency (ERE) and electricity consumption index (ECI) were investigated. The response surface method was adopted to optimize the three main factors (temperature, time, and municipal sludge proportion) affecting ERE and ECI. The results indicated that the response surface models established by Central Composite Design exhibited a good fit (model P<0.05, corresponding lack-of-fit p>0.05), with minimal deviation between predicted values and actual values. Municipal sludge proportion had a significant impact on ERE (P<0.05), while time exerted an extremely significant influence on ECI (P<0.0001). Temperature also had a significant impact on ECI (P<0.05). Through mathematical model optimization, the optimal conditions for achieving the highest ERE (0.470) and the lowest ECI (165.61) were determined to be 216 ℃, 83 minutes, and a 64% municipal sludge proportion, respectively. Additionally, a higher ERE (0.463) and lower ECI (171.60) could be obtained simultaneously at 208 ℃, 62 minutes, and a 52% municipal sludge proportion. To validate the results, three repeated experiments were conducted, and the errors between the experimental values and predicted values were found to be less than 5%. The findings of this study provide a scientific basis for the resource utilization and high-value utilization of municipal sludge and enteromorpha. By optimizing the co-hydrothermal carbonization process, it is possible to enhance energy recovery efficiency and reduce electricity consumption, contributing to the sustainable management of municipal sludge and the preservation of the environment.
Authors and Affiliations
ZHI Youwei|MOE Key Laboratory of Thermo-Fluid Science & Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, China, XU Donghai*|MOE Key Laboratory of Thermo-Fluid Science & Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, China, LIU Huanteng|MOE Key Laboratory of Thermo-Fluid Science & Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, China, XU Mingxin|MOE Key Laboratory of ThermoFluid Science & Engineering, School of Energy and Power Engineering, Xian Jiaotong University, China, ZHENG Peiyao|MOE Key Laboratory of ThermoFluid Science & Engineering, School of Energy and Power Engineering, Xian Jiaotong University, China
Keywords
Related Articles
- EP ID EP737166
- DOI 10.20078/j.eep.20240309
- Views 7
- Downloads 0
Mechanism of CO2 capture into isophorone diamine-water binary solid-liquid biphasic absorbent
Solid-liquid biphasic absorbents offer the advantages of easy separation and operation due to the formation of a solid phase after CO_2 capture, which can be separated by static precipitation. However, most existing abso...
Enhancements of mass transfer and heat transfer by microreactors and their applications in chemical engineering
Chemical reactions involving fine chemicals, environmental protection, and chemical drugs often necessitate continuous operation, high selectivity, and utmost safety. Particularly, when dealing with strong exothermic rea...
Peracetic acid activation for degradation of emerging contaminants: Processes, performance and mechanism
The removal of emerging contaminants (ECs) from water has been a hotspot and a challenge in the field of environmental engineering. Advanced oxidation processes (AOPs) based on peracetic acid (PAA) activation can generat...
The coordination complex formed by oxalic acid and chromate and the mechanism for enhanced photoreduction of Cr(Ⅵ) under visible-light irradiation
Oxalic acid, which mainly originates from root exudation and plant residue decomposition, is one of the most widely existiug carboxylic acids, and has a dramatic impact on the reduction of chromate in natural waters. In...
Research progress of immobilized microbial technology in remediation of heavy metal contaminated soil
Soil remediation industry plays an important role in promoting "double carbon" action and improving soil carbon sink capacity. However, the concealment, persistence and irreversibility of heavy metal pollution make the s...