The drying of sewage sludge by immersion frying

Silva, D. P.; Rudolph, Victor; Taranto, Osvaldir Pereira

doi:10.1590/s0104-66322005000200015

Cited by 22 publications

(19 citation statements)

References 8 publications

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“…Evaluation of the heat thermal resistance of this method and comparing with conductive and convective drying methods has shown that fry drying is presenting low heat thermal resistance which means faster drying. Wu et al [55], Silva et al [56] and Hong et al [57] study the influence of some operating conditions, such as the temperature of the used oil, different types of used and fresh oils, the sludge simple size and pressure effect. They find that tempera ture of the oil is the moist influent parameter (Fig.…”

Section: Presentation Of Innovative Methods Used In 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

195

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: Presentation Of Innovative Methods Used In 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

195

103

View full text Add to dashboard Cite

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“…In this study, characteristics of coal volatility are primarily investigated by heating spherical coal particles using the universal E/K model. First, to accommodate heat transfer modes such as radiation, convection, and conduction, we developed and executed an ''unsteady'' tri-diagonal matrix algorithm (TDMA) program for temperature distribution in particles [7]. We then determined a volatilization rate for particles by the Runge-Kutta method using the calculated temperature for sludge particles [10].…”

Section: Methodsmentioning

confidence: 99%

“…In order to reduce the overall cost of the process, researchers have proposed the use of recycled cooking oil [7,8].…”

Section: Introductionmentioning

confidence: 99%

Novel fry-drying method for the treatment of sewage sludge

Shin

Kim

Jang

et al. 2011

J Mater Cycles Waste Manag

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The purpose of this study is to introduce an efficient drying method named ''fry-drying technology'' for the treatment of sewage sludge. The basic principle of this method lies in the rapid escape of moisture from sludge material through its pores into the oil medium driven by the strong pressure gradient formed between sludge and oil media. This beneficial pressure distribution for moisture transfer can be established by the subtle combination of the difference of physical properties of specific heat and boiling temperature between water and oil. In order to determine the physical characteristics of this fry-drying technology, a series of experiments were performed in which important parameters, such as heating oil temperature, drying time, oil type, and sludge size, were varied. Numerical calculations using a single solid spherical particle model without any porosity were used to resolve the particle size effect associated with sludge drying.

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“…Operations using direct contact between the sludge and a liquid as a basis for drying have been reported in the literature, though incompletely (Bress et al, 1987;Kuntschar, 1996;Lue-Hing et al, 1996). The first systematic work about the drying of sewage sludge by immersion frying was presented by Pires da Silva (Silva et al, 2005(Silva et al, , 2003. These reported experimental tests which were carried out by immersing a cylinder (about 40 mm length Â 20-26 mm diameter) of municipal sewage sludge into bath containing 5 L soybean oil which was maintained at temperatures between 168 and 213 1C, well above the water boiling point.…”

Section: Overview Of Thermal Drying Of Sewage Sludge In the European mentioning

confidence: 99%

Immersion frying for the thermal drying of sewage sludge: An economic assessment

Peregrina

Rudolph

Lecomte

et al. 2008

Journal of Environmental Management

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This paper presents an economic study of a novel thermal fry-drying technology which transforms sewage sludge and recycled cooking oil (RCO) into a solid fuel. The process is shown to have significant potential advantage in terms of capital costs (by factors of several times) and comparable operating costs. Three potential variants of the process have been simulated and costed in terms of both capital and operating requirements for a commercial scale of operation. The differences are in the energy recovery systems, which include a simple condensation of the evaporated water and two different heat pump configurations. Simple condensation provides the simplest process, but the energy efficiency gain of an open heat pump offset this, making it economically somewhat more attractive. In terms of operating costs, current sludge dryers are dominated by maintenance and energy requirements, while for fry-drying these are comparatively small. Fry-drying running costs are dominated by provision of makeup waste oil. Cost reduction could focus on cheaper waste oil, e.g. from grease trap waste.

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The drying of sewage sludge by immersion frying

Cited by 22 publications

References 8 publications

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

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

Novel fry-drying method for the treatment of sewage sludge

Immersion frying for the thermal drying of sewage sludge: An economic assessment

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