Effects of Sewage Sludge on Combustion of Loading Alkali Metal Pulverized Coal

2012 ◽  
Vol 550-553 ◽  
pp. 2315-2318
Author(s):  
Li Hong Wei ◽  
Na Zhang ◽  
Tian Hua Yang ◽  
Lei Wang

The effects of sewage sludge on combustion of loading alkali metal pulverized coal is carried out by thermogravimetric analysis (TGA). The result shows sewage sludge decreases initial release temperature and ignition temperature of volatile matter(VM) during the combustion of loading alkali metal pulverized coal. The combustion of fixed carbon in coal was promoted by the metal material in sludge when the sludge mixing ratio(SMA) was lower than 20% or inhibited because of the cover of sludge ash when SMA was higher than 40%. Comparison of stacking curves of sludge and measured curves of loading alkali metal coal, finds that: (1) there is no effect between sludge and coal, for the volatilization of water and small molecule substance, the combustion characteristic curves are superimposed in both experimental curves; (2) the co-combustion is interactional and interrestricted continuous change process, can't direct obtain from superimposition of curves, for the combustion of VM and fixed carbon. While SMA is lower than 20%, the samples have good combustion characteristic than pure coal.

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. A. Tantawy ◽  
A. M. El-Roudi ◽  
Elham M. Abdalla ◽  
M. A. Abdelzaher

Raw sewage sludge was characterized by XRD, FTIR, SEM, and TGA techniques and incinerated in temperature range 650–950°C for 2 h. The effect of incineration temperature on the microstructure and pozzolanic activity of the resultant ash was investigated by techniques mentioned above as well as Chapelle test. It was concluded that incineration of sewage sludge affects the microstructure and pozzolanic activity of the resultant ash. During incineration at temperatures lower than 800°C, amorphous silica captures fixed carbon resulting from incomplete combustion conditions whereas at higher temperatures crystallization of amorphous silica was enhanced. Hydration products formed from hydrothermal treatment of silica fume with lime is amorphous whereas that of sewage sludge ash is fibrous. Hence, incineration of sewage sludge ash must be optimized at 800°C to preserve the pozzolanic activity of the resultant ash.


2021 ◽  
Author(s):  
Thi Ngoc Lan Thao Ngo ◽  
Kung-Yuh Chiang

Abstract This study investigates the kinetic behaviors and gas evolution of rice straw, sewage sludge, and their blends under co-thermal decomposition processes using Thermogravimetric analysis combined with Fourier-Transform Infrared Spectroscopy (TGA-FTIR). The experimental results indicate that sewage sludge could be enhanced the volatile matter decomposition in rice straw co-thermal process at lower temperatures. Activation energy decreases from 53.07 kJ/mol to 48.62 kJ/mol with an increase in sewage sludge addition from 50% to 80% under pyrolysis conditions. The major volatile components were aliphatic chains with double bonds, as well as carbonyl, hydroxyl, and C–H groups in organic compounds by FTIR identification. The tested materials characteristics in terms of volatile matter-to-fixed carbon (VM/FC) ratio was significantly affected the thermal degradation performance. Activation energy was decreased with increasing the VM/FC ratio. It implied that co-thermal reaction could be accelerated. In summary, the results could provide the important information for co-thermal treatment of sewage sludge and rice straw in commercial-scale plant.


2021 ◽  
pp. 127759
Author(s):  
Yifan Zhou ◽  
Jianxin Lu ◽  
Jiangshan Li ◽  
Chris Cheeseman ◽  
Chi Sun Poon

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3863
Author(s):  
Deng-Fong Lin ◽  
Wei-Jhu Wang ◽  
Chia-Wen Chen ◽  
Kuo-Liang Lin

Municipal incinerator bottom ash (MIBA) and sewage sludge ash (SSA) are secondary wastes produced from municipal incinerators. Landfills, disposal at sea, and agricultural use have been the major outlets for these secondary wastes. As global emphasis on sustainability arises, many have called for an increasing reuse of waste materials as valuable resources. In this study, MIBA and SSA were mixed with clay for ceramic tile manufacturing in this study. Raw materials firstly went through TCLP (Toxicity Characteristic Leaching Procedure) to ensure their feasibility for reuse. From scanning electron microscopy (SEM), clay’s smooth surface was contrasted with the porous surface of MIBA and SSA, which led to a higher water requirement for the mixing. Specimens with five MIBA mix percentages of 0%, 5%, 10%, 15%, and 20% (wt) and three SSA mix percentages of 0%, 10%, and 20% (wt) were made to compare how the two waste materials affected the quality of the final product and to what extent. Shrinkage tests showed that MIBA and SSA contributed oppositely to tile shrinkage, as more MIBA reduced tile shrinkage, while more SSA encouraged tile shrinkage. However, as the kiln temperature reached 1150 °C, the SiO2-rich SSA adversely reduced the shrinkage due to the glass phase that formed to expand the tile instead. Both MIBA and SSA increased water tile absorption and reduced its bending strength and wear resistance. Increasing the kiln temperature could effectively improve the water absorption, bending strength, and wear resistance of high MIBA and SSA mixes, as SEM showed a more compact structure at higher temperatures. However, when the temperature reached 1100 °C, more pores appeared and seemingly exhausted the benefit brought by the higher temperature. Complex interactions between kiln temperature and MIBA/SSA mix percentage bring unpredictable performance of tile shrinkage, bending strength, and water absorption, which makes it very challenging to create a sample meeting all the specification requirements. We conclude that a mix with up to 20% of SSA and 5% of MIBA could result in quality tiles meeting the requirements for interior or exterior flooring applications when the kiln temperature is carefully controlled.


2013 ◽  
Vol 67 (9) ◽  
pp. 1101-1105 ◽  
Author(s):  
Christian Vogel ◽  
Christian Adam ◽  
Don McNaughton

2006 ◽  
Vol 53 (12) ◽  
pp. 207-216 ◽  
Author(s):  
M. Boehler ◽  
H. Siegrist

The disposal of sewage sludge and the agricultural use of stabilised sludge are decreasing due to more stringent regulations in Europe. An increasing fraction of sewage sludge must therefore be dewatered, dried, incinerated and the ashes disposed of in landfills. These processes are cost-intensive and also lead to the loss of valuable phosphate resources incorporated in the sludge ash. The implementation of processes that could reduce excess sludge production and recycle phosphate is therefore recommended. Disintegration of biological sludge by mechanical, thermal and physical methods could significantly reduce excess sludge production, improve the settling properties of the sludge and reduce bulking and scumming. The solubilised COD could also improve denitrification if the treated sludge is recycled to the anoxic zone. However, disintegration partly inhibits and kills nitrifiers and could therefore shorten their effective solid retention time, thus reducing the safety of the nitrification. This paper discusses the potential of disintegration on sludge reduction, the operating stability of nitrification, the improvement of denitrification and also presents an energy and cost evaluation.


2017 ◽  
Vol 25 (5) ◽  
pp. 301-310 ◽  
Author(s):  
Jetsada Posom ◽  
Panmanas Sirisomboon

This research aimed to determine the higher heating value, volatile matter, fixed carbon and ash content of ground bamboo using Fourier transform near infrared spectroscopy as an alternative to bomb calorimetry and thermogravimetry. Bamboo culms used in this study had circumferences ranging from 16 to 40 cm. Model development was performed using partial least squares regression. The higher heating value, volatile matter, fixed carbon and ash content were predicted with coefficients of determination (r2) of 0.92, 0.82, 0.85 and 0.51; root mean square error of prediction (RMSEP) of 122 J g−1, 1.15%, 1.00% and 0.77%; ratio of the standard deviation to standard error of validation (RPD) of 3.66, 2.55, 2.62 and 1.44; and bias of 14.4 J g−1, −0.43%, 0.03% and −0.11%, respectively. This report shows that near infrared spectroscopy is quite successful in predicting the higher heating value, and is usable with screening for the determination of fixed carbon and volatile matter. For ash content, the method is not recommended. The models should be able to predict the properties of bamboo samples which are suitable for achieving higher efficiency for the biomass conversion process.


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