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M.b. Murillo - One of the best experts on this subject based on the ideXlab platform.
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Energetic assessment of air-steam gasification of Sewage Sludge and of the integration of Sewage Sludge pyrolysis and air-steam gasification of char
Energy, 2014Co-Authors: Noemí Gil-lalaguna, M.b. Murillo, José Luis Sánchez, María Atienza-martínezAbstract:Thermo-chemical treatment of Sewage Sludge is an interesting option for recovering energy and/or valuable products from this waste. This work presents an energetic assessment of pyrolysis and gasification of Sewage Sludge, also considering the prior Sewage Sludge thermal drying and the gasification of the char derived from the pyrolysis stage. Experimental data obtained from pyrolysis of Sewage Sludge, gasification of Sewage Sludge and gasification of char (all of these performed in a lab-scale fluidized reactor) were used for the energetic calculations. The results show that the energy contained in the product gases from pyrolysis and char gasification is not enough to cover the high energy consumption for thermal drying of Sewage Sludge. Additional energy could be obtained from the calorific value of the pyrolysis liquid, but some of its properties must be improved facing towards its use as fuel. On the other hand, the energy contained in the product gas of Sewage Sludge gasification is enough to cover the energy demand for both the Sewage Sludge thermal drying and the gasification process itself. Furthermore, a theoretical study included in this work shows that the gasification efficiency is improved when the chemical equilibrium is reached in the process.
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Air-steam gasification of char derived from Sewage Sludge pyrolysis. Comparison with the gasification of Sewage Sludge
Fuel, 2014Co-Authors: Noemí Gil-lalaguna, M.b. Murillo, José Luis Sánchez, V RuizAbstract:Abstract Air-steam gasification of char derived from fast pyrolysis of Sewage Sludge has been experimentally evaluated in a fluidized bed as a route towards a full recovery of energy from Sewage Sludge. The results have been compared with those obtained from the direct gasification of Sewage Sludge in order to evaluate how the previous pyrolysis stage affects the subsequent gasification process. The fixed carbon content in the solid increased after the pyrolysis stage so that heterogeneous reactions of carbon with steam or CO 2 assumed greater importance during char gasification than during Sewage Sludge gasification. Furthermore, char gasification led to an improvement in the gas yield -calculated on a dry and ash-free basis ( daf )- due to the increased concentration of carbon in the organic fraction of the solid after the pyrolysis step, with an increase in the average CO yield of about 70% -in terms of g/kg solid daf -. The reduction in the fraction of carbon which forms tar is another advantage of char gasification over the direct gasification of Sewage Sludge, with an average decrease of about 45%. Regarding the influence of the operating conditions, the response variables were mainly controlled by the same factors in both processes.
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study of the pyrolysis liquids obtained from different Sewage Sludge
Journal of Analytical and Applied Pyrolysis, 2009Co-Authors: I Fonts, M Azuara, G Gea, M.b. MurilloAbstract:Pyrolysis of Sewage Sludge in fluidized bed to produce bio-oil is under study as a useful way to valorise this waste. Sewage Sludge is the waste produced in the wastewater treatment plants. Its composition may change due to the origin and to the non-standardized treatments in the wastewater treatment plants. The pyrolysis of three samples of anaerobically digested Sewage Sludge obtained from three different urban wastewater treatment plants was studied in this work. The organic and inorganic matter composition, and the volatile and ash content of these Sewage Sludge samples were different. The influence of these parameters on the pyrolysis product distribution and on some characteristics of these products was studied. It was determined that the ash content of the raw material had an enormous influence on the Sewage Sludge pyrolysis. An increase in the ash content of the Sewage Sludge caused an increase in the gas yield and a decrease in the liquid and the solid yield with the operational conditions studied. The increase of the volatile content of the Sewage Sludge samples caused an increase in the liquid yield. The H 2 proportion was the most influenced non-condensable gas. It increased significantly with the ash content. The viscosity of the pyrolysis oils decreased when the ash content augmented. On the other hand, the water content depended on the organic composition of the Sewage Sludge samples. The chemical composition of the pyrolysis oils was also affected by the Sewage Sludge ash content above all the proportion of polyaromatic hydrocarbons and nitrogen-containing aromatic compounds. These compound groups increased with the augment of the Sewage Sludge ash content. The oxygen-containing aliphatic compounds and the steroids decreased with the ash content, although its proportion in the Sewage Sludge liquid was also influenced by the organic matter composition of the Sewage Sludge samples.
Gabriel Gascó - One of the best experts on this subject based on the ideXlab platform.
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Thermal analysis of soil amended with Sewage Sludge and biochar from Sewage Sludge pyrolysis
Journal of Thermal Analysis and Calorimetry, 2011Co-Authors: Gabriel Gascó, Jorge Paz-ferreiro, Ana MéndezAbstract:The main objective of the present study is to study the behaviour of Sewage Sludge and biochar from Sewage Sludge pyrolysis after addition to soil in a context of a temperate agricultural soil. For this, an incubation experiment was designed during 200 days. Carbon mineralization of soil amended with Sewage Sludge and biochar at two different rates (4 and 8 wt%) was evaluated. Differential thermal analysis, thermogravimetry and the first derivate of the TG were performed in oxidizing conditions on soil samples before and after incubation. Biochar obtained from Sewage Sludge pyrolysis at 500 °C was more stable in soil than original Sewage Sludge. After incubation experiment, the reduction of soil organic matter content was significantly lower in soil amended with biochar than in soil amended with Sewage Sludge. The thermostability index WL3/WL2 decreases after incubation in soil amended with biochar, however it increases in case of soil treated with Sewage Sludge.
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The influence of organic matter on Sewage Sludge pyrolysis
Journal of Analytical and Applied Pyrolysis, 2005Co-Authors: Gabriel Gascó, C.g. Blanco, F. Guerrero, A.m. Méndez LázaroAbstract:Abstract Four Sewage Sludges (SL) with different origins were selected from the Avila region (Spain). Sewage Sludge 1 (SL1) was primary Sewage Sludge without biological stabilization, Sewage Sludge 2 (SL2) and Sewage Sludge 4 (SL4) were obtained after anaerobic stabilization and Sewage Sludge 3 (SL3) was collected from a natural wastewater lake. The organic matter of Sewage Sludges was characterized and fractionated into humic acids (HA) and fulvic acids (FA) in order to study their influence on pyrolysis behavior. Preparation of cheaper carbon adsorbents was performed by a new method, without chemical activation with H 2 SO 4 or ZnCl 2 . Experimental results showed that carbon enrichment during pyrolysis treatment was well correlated ( R 2 > 0.95) with fulvic acid Sewage Sludge content for two temperatures and two reaction times used. Finally, the highest porosity development was obtained for SL2 (403 mI 2 /g) and SL4 (554 mgI 2 /g) both of which were found to have low HA/FA ratios.
V Ruiz - One of the best experts on this subject based on the ideXlab platform.
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Air-steam gasification of char derived from Sewage Sludge pyrolysis. Comparison with the gasification of Sewage Sludge
Fuel, 2014Co-Authors: Noemí Gil-lalaguna, M.b. Murillo, José Luis Sánchez, V RuizAbstract:Abstract Air-steam gasification of char derived from fast pyrolysis of Sewage Sludge has been experimentally evaluated in a fluidized bed as a route towards a full recovery of energy from Sewage Sludge. The results have been compared with those obtained from the direct gasification of Sewage Sludge in order to evaluate how the previous pyrolysis stage affects the subsequent gasification process. The fixed carbon content in the solid increased after the pyrolysis stage so that heterogeneous reactions of carbon with steam or CO 2 assumed greater importance during char gasification than during Sewage Sludge gasification. Furthermore, char gasification led to an improvement in the gas yield -calculated on a dry and ash-free basis ( daf )- due to the increased concentration of carbon in the organic fraction of the solid after the pyrolysis step, with an increase in the average CO yield of about 70% -in terms of g/kg solid daf -. The reduction in the fraction of carbon which forms tar is another advantage of char gasification over the direct gasification of Sewage Sludge, with an average decrease of about 45%. Regarding the influence of the operating conditions, the response variables were mainly controlled by the same factors in both processes.
María Atienza-martínez - One of the best experts on this subject based on the ideXlab platform.
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Sewage Sludge Torrefaction in an Auger Reactor
Energy & Fuels, 2014Co-Authors: María Atienza-martínez, J.f. Mastral, Javier Ábrego, J. CeamanosAbstract:A lab-scale auger reactor was used for the study of dry Sewage Sludge torrefaction. The influence of the torrefaction temperature (between 250 and 300 °C) and the solid residence time (between 13 and 35 min) on the product distribution and properties was investigated. The results have shown that both parameters affect dry Sewage Sludge torrefaction products to a similar extent within the ranges of study. The yield of torrefied Sewage Sludge decreases when increasing the torrefaction temperature and the solid residence time, while the yields of liquid and noncondensable gases show the opposite trend. Carbon dioxide and hydrogen sulfide are the major noncondensable products. The yield of water is higher than the initial moisture content of Sewage Sludge. Organic compounds are also released during torrefaction, especially under severe conditions. Torrefaction liquid separates into an organic phase and an aqueous phase. The former is rich in oxygen-containing aliphatic compounds and steroids and their derivat...
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Energetic assessment of air-steam gasification of Sewage Sludge and of the integration of Sewage Sludge pyrolysis and air-steam gasification of char
Energy, 2014Co-Authors: Noemí Gil-lalaguna, M.b. Murillo, José Luis Sánchez, María Atienza-martínezAbstract:Thermo-chemical treatment of Sewage Sludge is an interesting option for recovering energy and/or valuable products from this waste. This work presents an energetic assessment of pyrolysis and gasification of Sewage Sludge, also considering the prior Sewage Sludge thermal drying and the gasification of the char derived from the pyrolysis stage. Experimental data obtained from pyrolysis of Sewage Sludge, gasification of Sewage Sludge and gasification of char (all of these performed in a lab-scale fluidized reactor) were used for the energetic calculations. The results show that the energy contained in the product gases from pyrolysis and char gasification is not enough to cover the high energy consumption for thermal drying of Sewage Sludge. Additional energy could be obtained from the calorific value of the pyrolysis liquid, but some of its properties must be improved facing towards its use as fuel. On the other hand, the energy contained in the product gas of Sewage Sludge gasification is enough to cover the energy demand for both the Sewage Sludge thermal drying and the gasification process itself. Furthermore, a theoretical study included in this work shows that the gasification efficiency is improved when the chemical equilibrium is reached in the process.
Ana Méndez - One of the best experts on this subject based on the ideXlab platform.
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Thermal analysis of soil amended with Sewage Sludge and biochar from Sewage Sludge pyrolysis
Journal of Thermal Analysis and Calorimetry, 2011Co-Authors: Gabriel Gascó, Jorge Paz-ferreiro, Ana MéndezAbstract:The main objective of the present study is to study the behaviour of Sewage Sludge and biochar from Sewage Sludge pyrolysis after addition to soil in a context of a temperate agricultural soil. For this, an incubation experiment was designed during 200 days. Carbon mineralization of soil amended with Sewage Sludge and biochar at two different rates (4 and 8 wt%) was evaluated. Differential thermal analysis, thermogravimetry and the first derivate of the TG were performed in oxidizing conditions on soil samples before and after incubation. Biochar obtained from Sewage Sludge pyrolysis at 500 °C was more stable in soil than original Sewage Sludge. After incubation experiment, the reduction of soil organic matter content was significantly lower in soil amended with biochar than in soil amended with Sewage Sludge. The thermostability index WL3/WL2 decreases after incubation in soil amended with biochar, however it increases in case of soil treated with Sewage Sludge.