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.

Dried Municiple Sewage Sludge Gasification Experiment in Dual Fluidized Bed

2011 ◽  
Vol 383-390 ◽  
pp. 3799-3804
Author(s):  
Xiao Xu Fan ◽  
Lei Zhe Chu ◽  
Li Guo Yang
Keyword(s):  
Fly Ash ◽  
Sewage Sludge ◽  
Fluidized Bed ◽  
Calorific Value ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Test Results ◽  
Leaching Toxicity ◽  
Dual Fluidized Bed ◽  
Hot Test

The fuel characteristics of municipal sewage sludge are suitable for dual fluidized bed(DFB) gasification, which can get middle calorific value gas through volatile pyrolysis, and reduce volume through char combustion. The hot test results of municipal sewage sludge on DFB rig were showen that the temperature distribution along combustor heigh is uniform, and the carbon content of fly ash is about 2~3%. In the experiment, with the increase of gasifier temperatrue, the more volatile of the sewage sludge was pyrolyzed. When the temperature of the gasifier reached 800°C, the calorific value of gas was 6.9MJ/Nm3; the emissions of SO2, NOx and HCl were appropriate to the standard. The leaching toxicity of heavy metal of the fly ash was lower than the discharge standard.

scholarly journals Performance of a Fluidized Bed Furnace for Sewage Sludge Incineration.

1996 ◽  
Vol 22 (3) ◽  
pp. 458-466
Author(s):  
Yoshinori Imoto ◽  
Tadao Kasakura
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Sludge Incineration

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.

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.

Results of Long-Term Trials First Large Scale Fluidized Bed Furnaces for Sewage Sludge Worldwide Boosted by Oxygen

2003 ◽  
Author(s):  
Paul Ludwig ◽  
Gerhard Gross
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Large Scale ◽  
Combustion Process ◽  
Liquid Waste ◽  
Waste Material ◽  
Pure Oxygen ◽  
Fluidized Bed Combustion ◽  
Sludge Incineration ◽  
Dry Substance

Oxygen is required in every combustion process, including the incineration of sewage sludge. When air is used to provide oxygen the nitrogen it contains is only ballast which has to be heated up in the furnace and which further increases the volume of flue gas to be purified. The process for partial oxygen combustion (POC) jointly developed and patented by Messer Griesheim and Infraserv Ho¨chst avoids this problem. In this process, oxygen is blown directly and transversally into the fluidized bed at supersonic speed. The first promising test results were already presented at the 16th International Conference on Fluidized Bed Combustion 2001 in Reno. In the meantime we have three years of experience with detailed operating results. Up to 2000 m3/h of pure oxygen is blasted into the two furnaces transversally via the supersonic nozzles built into the walling. This results in a highly turbulent flow which considerably improves the mixing and the combustion in the fluidized bed. Using the POC method it has been possible to increase the combustion capacity of the systems from 130,000 to currently 160,000 t/a. The hourly throughput of waste material suitable for fluidized bed combustion has been increased by up to 40%. At the same time the combustion air volume has been reduced by 15% and the specific natural gas consumption by 35%. This considerably reduces the specific incineration costs (€ / t waste material). Alongside industrial and residential sewage sludges with calorific values of 500 to 11,000 KJ/kg (depending on the original substance) and dry-substance contents between 22 and 60%, other solid and liquid waste material suitable for fluidized bed combustion can also be processed, including bone meal, screenings, plastics granulate, spent active carbon, building timber, contaminated packaging material, organic solvents and urea waste. Calorific values can here fluctuate between 1,500 and 42,000 KJ/kg (depending on the original substance) and the dry-substance content between 5 and 100%. The specific emissions, e.g. carbon dioxide and nitrogen oxides per ton of incinerated waste material are reduced. Thus the POC process gives Infraserv a third virtual furnace at low investment cost, enabling it to respond to the demands of the market. With this technology, the status of “Best Available Technology” (BAT) was conferred upon the sewage sludge incineration plant operated by Infraserv Ho¨chst by the German Ministry for the Environment.

Production of fuels on the basis of sewage sludge through conditioning using high calorific value fractions

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Karl-Georg Schmelz ◽  
Anja Reipa ◽  
Hartmut Meyer
Keyword(s):  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Calorific Value ◽  
Fluidised Bed ◽  
Sludge Treatment ◽  
Heating Value ◽  
Fine Coal ◽  
Used Cars ◽  
Plastic Components

Emschergenossenschaft and Lippeverband operate 59 wastewater treatment plants which produce approx. 100,000 Mg TS of sewage sludge each year. Using sludge pressure pipelines, about 60 % of this sludge are transported to the central sludge treatment plant in Bottrop. The digested sludges are conditioned using fine coal and polymers and are dewatered using membrane filters. By adding coal, the heating value of the sludge is raised which enables autothermal combustion of the dewatered sludges in fluidised bed furnaces at the central sludge treatment plant. In order to replace coal, a fossil fuel, as conditioning agent, experiments were conducted using alternative materials with high heating values. The addition of shredder fluff agglomerates proved to be particularly successful. Shredder fluff agglomerates are a residue from the recycling of used cars and are generated in a multistage process (e.g. Volkswagen-SiCon Process) by separating the light shredder fraction (plastic components etc.) from the total shredder fluff. The fibrous material is outstandingly suitable for improving the dewaterability and for sufficiently raising the heating value of the dewatered sludge in order to enable autothermal combustion. Since first experiments showed very positive results, a full-scale long-term test-run will take place in 2007.

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.

Sign in / Sign up

Export Citation Format

Share Document