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.

scholarly journals Energy Recovery from Sewage Sludge: The Case Study of Croatia

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1927 ◽  
Author(s):  
Dinko Đurđević ◽  
Paolo Blecich ◽  
Željko Jurić
Keyword(s):  
Sewage Sludge ◽  
Energy Recovery ◽  
Fossil Fuels ◽  
Wastewater Treatment Plants ◽  
Energy Generation ◽  
Fuel Oil ◽  
Hard Coal ◽  
Solar Drying ◽  
Sludge Disposal ◽  
Sludge Drying

Croatia produced 21,366 tonnes of dry matter (DM) sewage sludge (SS) in 2016, a quantity expected to surpass 100,000 tonnes DM by 2024. Annual production rates for future wastewater treatment plants (WWTP) in Croatia are estimated at 5.8–7.3 Nm3/people equivalent (PE) for biogas and 20–25 kgDM/PE of sewage sludge. Biogas can be converted into 12–16 kWhel/PE of electricity and 19–24 kWhth/PE of heat, which is sufficient for 30–40% of electrical and 80–100% of thermal autonomy. The WWTP autonomy can be increased using energy recovery from sewage sludge incineration by 60% for electricity and 100% of thermal energy (10–13 kWhel/PE and 30–38 kWhth/PE). However, energy for sewage sludge drying exceeds energy recovery, unless solar drying is performed. The annual solar drying potential is estimated between 450–750 kgDM/m2 of solar drying surface. The lower heating value of dried sewage sludge is 2–3 kWh/kgDM and this energy can be used for assisting sludge drying or for energy generation and supply to WWTPs. Sewage sludge can be considered a renewable energy source and its incineration generates substantially lower greenhouse gases emissions than energy generation from fossil fuels. For the same amount of energy, sewage sludge emits 58% fewer emissions than natural gas and 80% less than hard coal and fuel oil. Moreover, this paper analysed the feasibility of sludge disposal practices by analysing three scenarios (landfilling, co-incineration, and mono-incineration). The analysis revealed that the most cost-effective sewage sludge disposal method is landfilling for 60% and co-incineration for 40% of the observed WWTPs in Croatia. The lowest CO2 emissions are obtained with landfilling and mono-incineration in 53% and 38% of the cases, respectively.

Sewage sludge drying by energy recovery from OFMSW composting: Preliminary feasibility evaluation

2014 ◽  
Vol 34 (5) ◽  
pp. 859-866 ◽  
Author(s):  
Elena Cristina Rada ◽  
Marco Ragazzi ◽  
Stefano Villotti ◽  
Vincenzo Torretta
Keyword(s):  
Sewage Sludge ◽  
Energy Recovery ◽  
Feasibility Evaluation ◽  
Sludge Drying

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.

Research on low temperature thermo-chemical conversion to oil process for sewage sludge

2000 ◽  
Vol 42 (3-4) ◽  
pp. 301-308 ◽  
Author(s):  
P. He ◽  
G. Gu ◽  
L. Shao ◽  
Y. Zhang
Keyword(s):  
Sewage Sludge ◽  
Low Temperature ◽  
Thermal Energy ◽  
Energy Recovery ◽  
Technological Development ◽  
Chemical Conversion ◽  
Reaction Conditions ◽  
Sludge Incineration ◽  
Secondary Pollutants ◽  
Incineration Process

The process of low temperature thermo-chemical conversion of municipal sewage sludge to oil is a new developing technology in developed countries, which is developed based on some poor fuels processing process in recent years. The process has the advantages of reasonable thermal energy recovery (the whole process is a net thermal energy exporting process), suitable cost and less secondary pollutants. This research included the reaction conditions versus the converted products distributions, the reaction conditions versus the ratio of the process thermal energy input and output, exploring of reaction mechanisms, creating of reaction kinetics models. These results contribute not only to having a clear understanding about the technological features and evaluating the prospectives of technological development, but also provide a sound basis for the technological development on a larger scale. It is concluded that: 1) the sludge treatment process is a net thermal energy producer. 2) The optimal conversion temperature is 270°C, referring to making energy recovery ratio maximum. 3) The parameters of simple conversion reaction kinetics are n=2, A=8.5 S-1 and E=37.9 KJ/mol. 4) The secondary pollutants of the process can be effectively controlled. 5) The investment intensity of the process could be similar to that of the sewage sludge incineration process, and the operational economics of the process are obviously superior to those of the sewage sludge incineration process. The research results show that the technical-economic feasibility of low temperature thermo-chemical conversion process is favorable, because the reaction conditions are more moderate and the separation process of the products is more easily realized.

scholarly journals Studies on the Gasification Performance of Sludge Cake Pre-Treated by Hydrothermal Carbonization

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1442 ◽  
Author(s):  
Sang Yeop Lee ◽  
Se Won Park ◽  
Md Tanvir Alam ◽  
Yean Ouk Jeong ◽  
Yong-Chil Seo ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Energy Recovery ◽  
Calorific Value ◽  
Hydrothermal Carbonization ◽  
Treatment Technique ◽  
Gasification Process ◽  
Cold Gas Efficiency ◽  
Sludge Cake ◽  
Gas Efficiency

Proper treatment and careful management of sewage sludge are essential because its disposal can lead to adverse environmental impacts such as public health hazards, as well as air, soil, and water pollution. Several efforts are being made currently not only to safely dispose of sewage sludge but also to utilize it as an energy source. Therefore, in this study, initiatives were taken to valorize sewage sludge cake by reducing the moisture content and increasing the calorific value by applying a hydrothermal treatment technique for efficient energy recovery. The sludge cake treated at 200 °C for 1 h was found to be the optimum condition for hydrothermal carbonization, as, in this condition, the caloric value of the treated sludge increased by 10% and the moisture content removed was 20 wt.%. To recover energy from the hydrothermally treated sludge, a gasification technology was applied at 900 °C. The results showed that the product gas from hydrothermally treated sludge cake had a higher lower heating value (0.98 MJ/Nm3) and higher cold gas efficiency (5.8%). Furthermore, compared with raw sludge cake, less tar was generated during the gasification of hydrothermally treated sludge cake. The removal efficiency was 28.2%. Overall results depict that hydrothermally treated sewage sludge cake could be a good source of energy recovery via the gasification process.

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.

Concept for an interlinked system of a sludge drying facility and a landfill for residual waste

1998 ◽  
Vol 38 (2) ◽  
pp. 119-125 ◽  
Author(s):  
P. Brautlecht ◽  
S. Gredigk
Keyword(s):  
Sewage Sludge ◽  
Rural Areas ◽  
Biological Treatment ◽  
Synergistic Effects ◽  
Electric Energy ◽  
Negative Effects ◽  
Sludge Disposal ◽  
Sludge Drying ◽  
Very High ◽  
Joint Treatment

The integration of a sewage sludge drying facility into landfill operation leads to a large number of synergistic effects. Two of these modules are examined more closely in this paper. If the thermal and electric energy produced in landfill operation are used for sewage sludge drying, the drying costs will be able to be reduced and the existing resources will be used in an ecologically acceptable way throughout the year. The joint treatment of the vent condensates resulting from sewage sludge drying and of landfill leachate suggests itself because both wastewaters show a similar composition. Tests carried out for this purpose have revealed that the efficiencies achieved especially in joint biological treatment are very high due to the good biodegradability of the vent condensates. Negative effects from the joint treatment of vent condensates on other procedures examined were not observed. With the help of comprehensive interlinked systems sewage sludge drying can even be realized in rural areas. This contributes to higher safety in sewage sludge disposal under economic, ecological and future-oriented aspects.

Influence of organic chlorine on emissions from sludge incineration by a pilot fluidised bed furnace

2000 ◽  
Vol 42 (9) ◽  
pp. 243-250 ◽  
Author(s):  
G. Mininni ◽  
V. Lotito ◽  
L. Spinosa ◽  
E. Guerriero
Keyword(s):  
Sewage Sludge ◽  
Operating Conditions ◽  
Critical Conditions ◽  
Fluidised Bed ◽  
Sludge Incineration ◽  
Before And After ◽  
Afterburning Chamber ◽  
Organic Chlorine ◽  
Set Up ◽  
Circulating Fluidised Bed

To demonstrate that sewage sludge incineration could be a safe operation if well conducted and that hazardous compounds could also be disposed of without problems in sludge incinerators plants, a research program has been set up by the Italian Water Research Institute on a demonstrative scale plant where a completely circulating fluidised bed furnace and a rotary kiln furnace can operate alternatively. In this paper results of tests performed by a fluidised bed furnace on sewage sludge spiked with highly chlorinated compounds under different operating conditions are presented. A deep investigation on micropollutants formation has been made at different sampling points: before and after bag house filter, and at the chimney. The experimental data show that concentrations of PCDDs+PCDFs (TE) and of PAHs do not strictly depend on the operation of the afterburning chamber and that a complete compliance with the European and Italian standards on the emissions were always achieved even in the most critical conditions investigated.

Sign in / Sign up

Export Citation Format

Share Document