Modeling of a solar and heat pump sludge drying system

Slim, Rayan; Zoughaib, Assaad; Clodic, Denis

doi:10.1016/j.ijrefrig.2008.03.003

Cited by 53 publications

(25 citation statements)

References 3 publications

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“…The application to drying process are widely found in the literature review such as solar food drying, however the application of this source of energy to dry wastewater sludge is still subject of intensive studies, such as recent works published by Bennamoun [1], Slim et al [48], Seginer and Bux [49 50] and Roux et al [51]. The specific character of solar drying is due to the variability of the applied operating conditions that entirely depends on climatic conditions, in particular: solar radiations, temperature and velocity of the air.…”

Section: Solar Drying Of Wastewater Sludgementioning

confidence: 99%

Review on fundamental aspect of application of drying process to wastewater sludge

Bennamoun

Arlabosse

Léonard

2013

Renewable and Sustainable Energy Reviews

197

103

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a b s t r a c tThe objective of this work is to give the fundamental information that should be known about wastewater sludge drying. Three methods are mainly applied: convective drying, conductive drying and solar drying, each one presenting different characteristics. When applying convective drying three phases are distin guished: adaptation phase, constant drying rate phase and falling drying rate phase. Experimental works show that several parameters influence the drying kinetic during this process, such as the origin of the sludge and operating conditions. Imaging techniques allow observing three phenomena that happen during convective drying: shrinkage, cracks and skin formation. When applying conductive drying and considering the torque variations, the product passes through: pasty phase, lumpy phase and granular phase. The results show no regular shape of the drying kinetic with high values of the drying rate and the heat transfer coefficient during the first phase. A special focus is given into the sticky phase which reduces performances of the dryer. The third applied drying method is solar drying, which depends wholly on climatic conditions, such solar radiations and air temperature. Besides, for this method no regular shape of the drying kinetic can be observed, with high drying rate values during favorable conditions and low drying rate values during unfavorable conditions. The presented studies dealing with solar drying of wastewater sludge are limited to the variations of the different air temperatures registered inside and outside the drying chamber with the product temperature and their humidity with study of the pathogen reduction. Finally, some innovative developed methods are exposed in this review, such as the use of frying and super heated steam.

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Section: Solar Drying Of Wastewater Sludgementioning

confidence: 99%

Review on fundamental aspect of application of drying process to wastewater sludge

Bennamoun

Arlabosse

Léonard

2013

Renewable and Sustainable Energy Reviews

197

103

View full text Add to dashboard Cite

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“…Besides anaerobic stabilization and mechanical dewatering, urban sludge drying is often an essential step to facilitate later management such as valorization or storage, since it reduces the amount of end material to a minimum, while eliminating most odor and pathogen problems [3]. This process can be applied prior to further thermal treatment: conventional incineration, co-incineration with coal or other fuels, vitrification, pyrolysis, or may be the final step the product of which can be further handled in agriculture [4].…”

Section: Introductionmentioning

confidence: 99%

“…The natural solar drying is subject of many experimental studies [3,[7][8][9]. The performances of the drying systems change through the period of use, the geographical situation of the place where the experimental work was done, what is more it depends on the origin of the wastewater sludge [10].…”

Section: Introductionmentioning

confidence: 99%

Solar Greenhouse Drying of Wastewater Sludges Under Arid Climate

Belloulid

Hamdi

Mandi

et al. 2016

Waste Biomass Valor

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Wastewater sludges were dried in an open greenhouse pilot in order to provide experimental data about solar greenhouse drying under an arid climate during hot and cold periods. Climatic conditions, solids contents and geometric dimensions were constantly measured. The shape change of samples was constantly recorded with digital scan. The results indicated that solar greenhouse drying reduced the moisture content from about 4 kg water/kg DS to 0.08 kg water/kg DS in hot period and to 0.2 kg water/kg DS in cold period in only 72 h. The higher values of drying rate were obtained in hot season. The maximum ranges obtained were 0.2 kg water/kg DS.h and 0.13 kg water/kg DS.h in hot and cold campaigns, respectively. Furthermore, a large volume reduction representing at least 80 % of initial volume was observed in both periods after 72 h of drying process. Also, shrinkage and cracks phenomena took place inside sludges. An improvement of the microbial condition of treated sludges was noted in hot campaign with a decrease by one order of magnitude after only 24 h for total and fecal coliforms and after 72 h for Clostridium perfringens, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus contents. These pathogenic bacteria were almost constant for fresh and dry sludges in cold period. The paper recommends the solar drying in hot as in cold periods under arid climate considering its average drying rate outside the rainy periods.

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“…However, in most cases it is not cost-effective because of the high energy demands and the by-product status of sludge. Therefore, for the purpose of cost controlling, many studies have focused on the design of new thermal dryers, the optimization of thermal-drying operation and the use of renewable energy (Mathioudakis et al, 2009;Deng et al, 2009;L eonard et al, 2008;Slim et al, 2008;Bennamoun, 2012). In addition, some other studies have been concerned with the drying behavior of sludge with different properties (Ruiz et al, 2007;Wang et al, 2011).…”

Section: Introductionmentioning

confidence: 99%