Effects of air parameters on sewage sludge drying characteristics and regression analyses of drying model coefficients

Zheng, Qiushuang; Hu, Ziyuan; Li, Penggang; Ni, Long; Huang, Guanying; Yang, Yao; Zhou, Liangyu

doi:10.1016/j.applthermaleng.2021.117501

Cited by 22 publications

(9 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, the Page model more accurately reflects the pattern of moisture changes in sludge drying than the other six mathematical models. This conclusion is consistent with the study of Zheng et al (Zheng et al 2021). 5.…”

Section: Mathematical Models Of the Drying Processsupporting

confidence: 94%

Moisture content prediction of municipal sludge drying process based on genetic algorithm optimized BP neural network

Zhang,

Wang

2024

Preprint

View full text Add to dashboard Cite

Municipal sludge drying process of internal moisture detection difficulties, and in order to predict the change rule of the internal moisture in the hot-air drying process of municipal sludge, the moisture change of municipal sludge under different drying conditions was monitored through experiments. The moisture prediction model of municipal sludge drying process was established by optimizing the BP neural network using mathematical model, back-propagation (BP) neural network and genetic algorithm (GA), and the performance analysis of the model was carried out. In addition, a sensitivity analysis of the GA-BP model was performed. The results showed that the temperature had the most significant effect on the drying process of municipal sludge, reducing the thickness of the mud layer could improve the drying rate of sludge, and the moisture reduction rate of municipal sludge showed a fast and then a slow trend during the whole drying process. Through the performance analysis, the coefficient of determination of the test set of GA-BP model is 0.9999, and the root mean square error is only 0.0039, which means that the GA-BP model has a better prediction effect and can predict the dynamic change of moisture in the drying process of municipal sludge more accurately. The sensitivity analysis shows that the drying time and drying temperature have the greatest influence on moisture ratio(MR), and the results of the study can provide a theoretical basis for the optimization of the sludge drying process and procedure, and provide a powerful reference for guiding the resource utilization of sludge.

show abstract

Section: Mathematical Models Of the Drying Processsupporting

confidence: 94%

Moisture content prediction of municipal sludge drying process based on genetic algorithm optimized BP neural network

Zhang,

Wang

2024

Preprint

View full text Add to dashboard Cite

show abstract

“…At the end of the observed period, the residual sludge humidity resulted close to 5%. The residual humidity obtained in this study was noticeable lower compared with that achieved with conventional thermal dryer and conventional solar greenhouses [16,17]. Moreover, the obtained results indicated that the proposed configuration enabled a faster drying kinetic than that obtained using conventional solar greenhouse.…”

Section: Sludge Residual Humiditymentioning

confidence: 56%

Enhanced Sewage Sludge Drying with a Modified Solar Greenhouse

et al. 2022

View full text Add to dashboard Cite

This work reports the results obtained with an innovative configuration of a closed-static solar greenhouse for sludge drying. The novelty of the solar greenhouse configuration consisted in using a forced ventilation system to provide hot air for sludge drying and the utilization of solar irradiation for energy supply. Wet sewage sludge (97% humidity) was successfully dried up to a residual humidity close to 5% after 25 days during wintertime. The increase of the airflow rate supplied under the sludge bed improved the sludge drying rate. Moreover, the fraction of volatile suspended solids decreased from 70% to 41% after 13 days, indicating that air supply promoted the simultaneous stabilization of the sludge as a side-effect to the drying process. Overall, the specific energy consumption per ton of evaporated water was estimated to approximately 450 kWh/t, resulting in about 55% of energy demand lower than a conventional thermal drying system, while using only free solar energy. The achieved high weight reduction of up to 99% implies a noticeable reduction of the excess sludge handling costs, indicating that solar greenhouse drying is a highly interesting opportunity for sludge drying in medium-small sized WWTPs.

show abstract

Section: Discussionmentioning

confidence: 99%

“…The results showed that the number of macropores increased gradually with the increase in the particle size of soil aggregates, which was consistent with previous studies. Then, the method of hot air drying [10,11] was used to blow hot air into the wet soil to solve the problem of excessive moisture in the soil pores. The study found that hot air would produce different forms of heat flow under different sized pore structures, thus producing different heat and mass transfer rules.…”

Section: Discussionmentioning

confidence: 99%

“…To solve the problem of steam condensation blocking soil pores, the first thing is to remove the condensation that is clogging the pores in the soil. According to previous research on the sludge drying process, hot air heating is used to remove excess water from the sludge [10,11]. Building on the concept of hot air heating for dehumidification, to more effectively clear blocked pores and improve steam diffusion efficiency, it is essential to further investigate the impact of hot air on water heating and evaporation in soil pores of different sizes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Study on the Temperature and Water Distribution of Hot Air in Red Loam Based on Soil Continuous Cropping Obstacles

Yang,

Ameen,

Yang

et al. 2024

Agriculture

View full text Add to dashboard Cite

In recent years, the problematic circumstances of the constant cropping problem in facility crops have become increasingly serious. Compared to chemical disinfection, soil steam disinfestation offers the benefits of environmental protection and being pollution-free, which can effectively reduce the problem of constant cropping in crops. However, during the steam disinfection procedure, a large quantity of liquid water is formed due to the condensation of high-temperature steam, which causes soil pore blockage, seriously affecting the mass and heat transfer efficacy of steam and, thus, affecting the disinfection efficiency. Therefore, to solve this problem, this paper proposes the use of hot air dehumidification to remove excess water from soil pores and achieve the goal of dredging the pores. However, further exploration is needed on how to efficiently remove excess water from different pore structures through hot air applications. Therefore, this paper first used CFD simulation technology to simulate and analyze the hot air flow field, mass, and heat transfer in soil aggregates of different sizes (<2 mm to >8 mm). Then, based on the soil hot air heating experimental platform, research was conducted on the mass and heat transfer mechanism of hot air under diverse soil pore conditions. The results show that as the soil particle size increases from <2 mm to >8 mm, the number of soil macropores also increases, which makes the soil prone to the formation of macropore thermal currents, and the efficiency of hot air heating for dehumidification first increases and then decreases. Among them, the 4–6 mm treatment has the best dehumidification effect through hot air heating, with a deep soil temperature of up to 90 °C and a water content reduction of 6%. The 4–6 mm treatment has a high-temperature heating and dehumidification area of 15–20 cm deep. The above results lay the theoretical foundations for the parameters of hot air heating and dehumidification operations, as well as the placement of the hot air pipe. This paper aims to combine hot air dehumidification technology, for the removal of excess water from soil, and dredging soil pores, ultimately achieving the goal of improving soil steam disinfection efficiency.

show abstract

Effects of air parameters on sewage sludge drying characteristics and regression analyses of drying model coefficients

Cited by 22 publications

References 41 publications

Moisture content prediction of municipal sludge drying process based on genetic algorithm optimized BP neural network

Moisture content prediction of municipal sludge drying process based on genetic algorithm optimized BP neural network

Enhanced Sewage Sludge Drying with a Modified Solar Greenhouse

Study on the Temperature and Water Distribution of Hot Air in Red Loam Based on Soil Continuous Cropping Obstacles

Contact Info

Product

Resources

About