scholarly journals Combustion Characteristics of Hydrochar and Pyrochar Derived from Digested Sewage Sludge

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4164 ◽  
Author(s):  
Pablo J. Arauzo ◽  
María Atienza-Martínez ◽  
Javier Ábrego ◽  
Maciej P. Olszewski ◽  
Zebin Cao ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Reaction Pathways ◽  
Energy Yield ◽  
Combustion Kinetics ◽  
Coal Blending ◽  
Carbon Recovery ◽  
And Storage ◽  
Kinetics Of ◽  
Digested Sewage Sludge ◽  
Lower Carbon

In this paper, hydrochars and pyrochars were produced at 260 °C under different residence times (2 and 4 h) using anaerobic digested sewage sludge (SSL) as initial feedstock. The effect of reaction time on the fuel properties of hydrochars and pyrochars was evaluated. Moreover, the combustion kinetics of raw SSL and the derived pyrochars and hydrochars without coal blending were determined at two different air flows (20 and 90 mL/min) and compared. In the same conditions, the yield of hydrochar was significantly lower than that of pyrochar, confirming the different reaction pathways followed in each process. The results showed hydrochars have lower carbon recovery and energy yield than pyrochars, making the latter more suitable for energy purposes. The thermogravimetric combustion study showed that both thermochemical treatments increased the ignition temperature but decreased the burnout temperature, which results in higher stability during handling and storage. However, raw SSL is better for combustion than hydrochar according to the combustibility index. In addition, the kinetic study showed that the activation energy of the combustion of biochars, especially pyrochar, is lower than that of raw SSL, which is advantageous for their combustion.

The Staged Thermal Conversion of Sewage Sludge in the Presence of Oxygen

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Halina Pawlak-Kruczek ◽  
Mateusz Wnukowski ◽  
Krystian Krochmalny ◽  
Mateusz Kowal ◽  
Marcin Baranowski ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Sewage Sludge ◽  
Thermal Processing ◽  
Thermal Conversion ◽  
Single Step ◽  
Energy Yield ◽  
Mass Yield ◽  
Optimal Conditions ◽  
Kinetics Of ◽  
By Products

This study compares a staged thermal processing of the sewage sludge, with single step, integrated thermal processing. The aim of this study is to find the optimal conditions for drying and subsequently for carbonization/torrefaction of sewage sludge, regarding the energy consumption. This study presents the results of the drying tests performed at laboratory scale convective dryer for different parameters of drying agent (air). The tests were focused on finding and developing a method of drying that allows to minimize the energy consumption. Subsequently, both dry and vapothermal torrefaction was performed in the presence of oxygen. The kinetics of drying, using low quality heat as well as the properties of products and by-products of torrefaction in both regimes were determined. The process was characterized by mass yield and energy yield in both of the cases. There has been only scarce amount of literature studies published on the torrefaction of sewage sludge so far, without a detailed study of the composition of the torgas and tars of such origin. Performed study enables a comparison of two distinct scenarios of the processing, i.e., drying followed by dry torrefaction with a single stage of vapothermal torrefaction.

Kinetics of forced aerated biodegradation of digested sewage sludge-reed mixtures at different temperatures

2012 ◽  
Vol 95 ◽  
pp. S128-S133 ◽  
Author(s):  
V. Sánchez Arias ◽  
F.J. Fernández ◽  
L. Rodríguez ◽  
E.I. Stentiford ◽  
J. Villaseñor
Keyword(s):  
Sewage Sludge ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Digested Sewage Sludge

scholarly journals Determining the mass-related reaction effectiveness factor of large, nonspherical fuel particles for bridging between intrinsic and apparent combustion kinetics

2019 ◽  
Vol 141 (2) ◽  
pp. 797-806 ◽  
Author(s):  
Tibor Szűcs ◽  
Pal Szentannai
Keyword(s):  
Combustion Process ◽  
Effectiveness Factor ◽  
Cfd Modeling ◽  
Combustion Kinetics ◽  
Kinetic Measurements ◽  
Environmental Requirements ◽  
Fuel Particles ◽  
Related Reaction ◽  
Kinetics Of ◽  
Internal Pore

AbstractThe utilization of challenging solid fuels in the energy industry is urged by environmental requirements. The combustion kinetics of these fuel particles differs markedly from that of pulverized coal, mainly because of their larger sizes, irregular (nonspherical) shapes, and versatile internal pore structures. Although the intrinsic reaction kinetic measurements on very small amounts of finely ground samples of these particles are mostly available, a bridge toward their apparent reaction modeling is not evident. In this study, a method is introduced to build this bridge, the goodness of which was proved on the example of an industrially relevant biofuel. To do this, the results of a macroscopic combustion measurement with real samples in a well-modelable environment have to be used, and for considering some not negligible effects, 3D CFD modeling of the experimental environment is also to be applied. The outcome is the mass-related reaction effectiveness factor as a function of the rate of conversion. This variable can be considered as the active fraction of the entire particle mass on its periphery, and it can be used as the crucial element in modeling the combustion process of the same particle under other circumstances by including the actual boundary conditions. Another advantage of this method is its covering inherently the entire combustion process (water and volatile release, and char combustion) and also its applicability for reactors utilizing bigger particles like fluidized bed combustors.

Combustion kinetics of swine manure and algal solids

2015 ◽  
Vol 123 (1) ◽  
pp. 687-696 ◽  
Author(s):  
Mahmoud A. Sharara ◽  
Sammy S. Sadaka ◽  
Thomas A. Costello ◽  
Karl VanDevender ◽  
Julie Carrier ◽  
...  
Keyword(s):  
Swine Manure ◽  
Combustion Kinetics ◽  
Kinetics Of
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