Study on the Biochar Yield and Heat Required during Pyrolysis of Two-Phase Olive Mill Waste

Abstract

The present study analyzes the effect of several operating factors (initial sample mass, heating rate, conditions of the crucible, and inorganic matter content) on the pyrolysis of two-phase olive mill waste. Simultaneous TGA−DSC measurements were performed according to a one-half fractional factorial design to obtain statistically significant conclusions. The results from this screening design pointed out that the behavior of the TPOMW pyrolysis process is statistically affected to a greater or lesser extent by the four factors analyzed. The factors related to the promotion of secondary charring reactions (the initial sample mass and the conditions of the crucible) had the main influence on both the apparent heat and charcoal yield. The enhancement of the charring reactions implies a dramatic decrease in the apparent heat of pyrolysis from highly endothermic (2559 ± 100 kJ kg −1 ) to slightly exothermic (−44.2 ± 49 kJ kg −1 ). On the other hand, a new approach for modeling the apparent kinetics of TPOMW pyrolysis (both primary decomposition and secondary charcoal production) is proposed. The performance of this approach is good enough to provide satisfactory estimations of a large number of unknown kinetic parameters in very short computational times.

Production and Dry Mechanochemical Activation of Biochars Derived from Moroccan Red Macroalgae Residue and Olive Pomace Biomass for Treating Wastewater: Thermodynamic, Isotherm, and Kinetic Studies

“…It was reported that the inorganic matter, especially alkali metals (i.e., K, Na, etc.) that represent the ash content, can play a crucial role in shifting the balance in favor of heat release because of its catalytic effect, which simultaneously reduces the energy requirements for the volatilization of biochemical compounds and promotes the exothermic secondary char formation . Therefore, it could be suggested that the high ash content in AG (9.1 wt %) has promoted BC-forming reactions in account of decomposition reactions.…”

Pyrolysis and char reactivity of a poor-quality refuse-derived fuel (RDF) from municipal solid waste

“…An interesting finding is the fact that the highest devolatilization rate for tests conducted at 40°C min − 1 was reached at a lower temperature, in comparison with the case of the samples pyrolyzed at 5°C min −1 (around 280°C and 305°C, respectively). Usually, pyrolysis profiles shift to a higher temperature region when heating rate is increased, due to the fact that the heat required for devolatilization is reached later at higher temperatures (i.e., heat transfer limitations) [40][41][42][43][44][45]. Thus, the observed result suggests that an increase from 5 to 40°C min −1 could lead to a faster release of Table 2 Matrix of the factorial design adopted to analyze the pyrolysis behavior of RDF.…”

One-pot activation and pyrolysis of Moroccan Gelidium sesquipedale red macroalgae residue: production of an efficient adsorbent biochar

“…According to these results, the production yields of BC and AcBC varied from 31% to 43% of the initial dry weight. These variations in the mass yields were due to the effect of chemical catalysts on volatilization and solid formation reactions (Manyà et al 2013). For the unactivated biochar (BC), the production yield was 6% higher than the 28% yield reported by Francavilla et al (2014).…”

“…In addition, it was reported that during biomass pyrolysis, inorganic matter, especially alkali metals (i.e., K, Na, etc. ), can catalyze both biomass decomposition and biochar-forming reactions (Manyà et al 2013).…”