Economic Optimization of Indirect Sewage Sludge Heat Dryer Unit for Sewage Sludge Incineration Plants

2015 ◽  
Author(s):  
Sinan Demir ◽  
Orkun Karabasoglu ◽  
V'Yacheslav Akkerman ◽  
Aysegul Abusoglu
Keyword(s):  
Sewage Sludge ◽  
Minimum Cost ◽  
Economic Optimization ◽  
Two Phase ◽  
Economic Relations ◽  
Sludge Incineration ◽  
Oil Tank ◽  
Sludge Drying ◽  
Two Phase Heat Transfer ◽  
Thermal Oil

This paper presents the economic optimization of indirect sewage sludge heat dryer for sewage sludge incineration plants. The objective function based on two-phase heat transfer, and economic relations is provided to demonstrate the optimum size for the minimum investment cost. De-watered sludge is fed into the dryer with a mass flow rate of 165 tons per day and consists of 27% dry matter. After the sludge drying process, the dryness of sludge increases up to 40%. In the indirect sludge dryer unit, thermal oil is used to heat the dryer wall and to prevent heat loss. Thermal oil is circulated in a closed cycle and gathered into an oil tank. Total cost of the sludge dryer unit changes proportional to the dryer area. The optimum dryer area is found as 32.54 m2. The corresponding minimum cost is found as $35,700.

A design model of sewage sludge incineration plants with energy recovery

1997 ◽  
Vol 36 (11) ◽  
pp. 211-218 ◽  
Author(s):  
G. Mininni ◽  
R. Di Bartolo Zuccarello ◽  
V. Lotito ◽  
L. Spinosa ◽  
A. C. Di Pinto
Keyword(s):  
Sewage Sludge ◽  
Energy Recovery ◽  
Electric Energy ◽  
Design Model ◽  
Gas Treatment ◽  
Treatment Line ◽  
Sludge Incineration ◽  
Afterburning Chamber ◽  
Sludge Cake ◽  
Sludge Drying

A design model of sewage sludge incineration plants has been developed to examine the possibilities for energy recovery. It was evident that, without sludge drying, there was a high fuel (methane) consumptions (149-192 Nm3/t sludge cake at 25% concentrations), but considerable amount of electric energy is obtainable (391-515 kWh/t sludge cake). Sizes of boiler and whole exhaust gases treatment line are in this case quite large. On the contrary, fuel consumption can be lowered down to 20 Nm3/t sludge cake at 44% concentration by introducing sludge drying. In this case fuel is needed only in the afterburning chamber, as the combustion in the fluidized bed furnace is autothermal. Boiler and exhaust gas treatment line are considerably reduced in size when power production is not performed, thus allowing a simpler and smaller plant to be designed.

Improved Efficiency of Sewage Sludge Incineration by Preceding Sludge Drying

1990 ◽  
Vol 22 (12) ◽  
pp. 269-276 ◽  
Author(s):  
Heinz Brechtel ◽  
Hartmut Eipper
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Calorific Value ◽  
Primary Energy ◽  
Operational Experience ◽  
Special Equipment ◽  
Sludge Incineration ◽  
Technical Modifications ◽  
Sludge Drying ◽  
Near Future

Normally, mechanical dewatering of sewage sludges is not sufficient for a self-supporting combustion, even if combustion is ensured in the fluidized bed furnace. The heat balance can be compensated by firing additional fuels of higher calorific value and a preceding sludge drying using the heat, which is generated during combustion. The most favoured solution is an indirect drying in special equipment adapted to the state of the sewage sludge to be burnt. Heating surfaces and the steam transfer the thermal energy of the flue gases to the mechanically dewatered sludge. The development of malodours and pollutants in the vapours is controlled by an appropriate process flow. The process entails not only an economy of primary energy but also an increase in the furnace throughput. In Wuppertal-Buchenhofen, the fluidized bed fired sludge incineration plant has been operating for 12 years.In the near future it will be brought up to date by retrofitting such a drying system. The foreseeable effects have already been investigated and operational experience gained with other plants has been taken into account. The technical modifications, which are being considered, the operational influences expected, as well as all consequences with regard to investment and operating costs, have been outlined.

Mercury Removal in the Flue Gas Scrubber of a Fluidized-Bed Sewage Sludge Incinerator

2003 ◽  
Author(s):  
O. Malerius ◽  
J. Werther ◽  
M. Mineur
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Flue Gas ◽  
Minimum Cost ◽  
Mercury Removal ◽  
Fluidized Bed Combustion ◽  
Mercury Compounds ◽  
Sludge Incineration ◽  
Mercury Capture ◽  
Operation Parameters

The fluidized bed sewage sludge incineration plant of the city of Hamburg started its operation in May, 1997. An acid scrubber was designed as the main sink of mercury. A first modification of the mercury removal concept was presented on the 16th Fluidized Bed Combustion Conference in 2001 [1]. Mercury compounds are now dissolved in the acid scrubber and precipitated with a solution of sodium dimethyldithiocarbamate. In the year 2002 the operation of the acid scrubber has been investigated to optimize the scrubber performance. Suspension pH, amount of precipitant and density of the scrubber suspension were varied to find the optimum operation parameters for the capture of mercury at minimum cost. It was found that with an increase of the density of the scrubber suspension the mercury removal efficiency was enhanced such that the dosage of the precipitant could be decreased significantly. After this optimization process the pollutant streams into the environment were minimized. The paper presents the influence of the scrubber operation parameters on the mercury capture using continuous mercury measurements in the flue gas upstream and downstream of the scrubber. The results of this investigation led to both a minimization of the pollutant streams into the atmosphere and a reduction of the operation cost.

Sewage Sludge Flow and Drying Characteristics in Paddle Dryers

2013 ◽  
Vol 334-335 ◽  
pp. 365-368 ◽  
Author(s):  
Hou Lei Zhang ◽  
Xin Zhi Liu ◽  
Shu Guang Zhu ◽  
Bin Li
Keyword(s):  
Sewage Sludge ◽  
Inlet Temperature ◽  
Limited Data ◽  
Drying Characteristics ◽  
Sludge Disposal ◽  
Mass Flowrate ◽  
Energy Consuming ◽  
Sludge Drying ◽  
Thermal Oil ◽  
Monotonic Relation

Sewage sludge from wastewater treatment is being more and more produced in many countries. For sewage sludge disposal, drying operation is usually required and greatly energy-consuming. Paddle dryers, one kind of indirect dryers, are widely used in removing moisture of sewage sludge recently, but the design, to some extent, still depends on empirical and limited data. In this paper, we presented preliminary experimental results of sewage sludge drying based on a 3 m2paddle dryer prototype. The effects of thermal oil inlet temperature on outlet moisture content and mass flowrate of initial sludge are recorded and analyzed. A simple monotonic relation between mass flowrate of initial sludge and thermal oil inlet temperature does not exist. Besides, we performed the drying experiment of adding low-value biomass (rice husk) into wet sewage sludge. The results show that the drying performance is improved significantly.

MICROSCALE TWO PHASE HEAT TRANSFER ENHANCEMENT IN POROUS STRUCTURES

Equipment ◽  
2006 ◽  
Author(s):  
Leonid L. Vasiliev ◽  
A. Zhuravlyov ◽  
A. Shapovalov ◽  
L. L. Vasiliev, Jr
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Porous Structures ◽  
Transfer Enhancement ◽  
Two Phase ◽  
Two Phase Heat Transfer

New Approach to the Emission of Flue Gases Caused by Sludge Incineration in the Netherlands

1992 ◽  
Vol 25 (4-5) ◽  
pp. 307-314 ◽  
Author(s):  
A. W. van der Vlies ◽  
J. H. B. te Marvelde
Keyword(s):  
Sewage Sludge ◽  
The Netherlands ◽  
Flue Gas ◽  
Flue Gases ◽  
Gas Purification ◽  
Incineration Plant ◽  
New Approach ◽  
Sludge Incineration ◽  
Limited Degree ◽  
The Town

Recycling of sewage sludge will soon no longer be possible in The Netherlands, or will be possible only to a very limited degree. For that reason, part of the sewage sludge will have to be incinerated. This will happen particularly in those areas where tipping space is very limited. A sludge incineration plant is planned to be built in the town of Dordrecht, with a capacity of 45,000 tonnes dry solids per year. The plant will be subject to the very strict flue gas emission requirements of the Dutch Guideline on Incineration. The Guideline demands a sophisticated flue gas purification procedure.

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