Elucidating The Thermal Decomposition Mechanism and Pyrolysis Characteristics of Biorefinery-Derived Humins From Sugarcane Bagasse And Rice Husk

Biomass-derived humins produced in the biorefining of biomass represent an attractive feedstock for thermochemical processes and other carbon-derived platform chemicals. However, in most works, humins are merely a by-product that is not further analyzed. This work presents the purification and characterization of humins derived from sugarcane bagasse and rice husks (H-SCB and H-RH respectively), followed by the kinetic and thermodynamic analysis of its pyrolysis. Pyrolysis was examined via thermogravimetric analysis (TGA), and a global reaction model was adopted to address pyrolysis kinetics. To understand the pyrolysis process of humins and boost the quality of fit between the kinetic model and thermoanalytical data, the analyses were based on the Vyazovkin isoconversional method. The activation energy of H-SCB increased from 166.09 to 329.76 kJ mol-1. In contrast, the activation energy of H-RH decreased from 163.31 to 84.99 kJ mol-1. According to the results of the generalized master plot approach, the governing reaction mechanism shifted among order-based models, nucleation, and diffusion-controlled particle mechanisms. Derived thermodynamic properties showed that the heat absorbed helps the humins to achieve a more ordered state close to a conversion of 0.50. As far as we know, these findings are the first reported data on the forecast kinetic curves and pyrolysis mechanism of biorefinery-derived humins from sugarcane bagasse and rice husk, and these results will enable process design for the thermochemical conversion of these emerging materials to produce energy and other products.

Thermal Analysis of a Metal–Organic Framework ZnxCo1-X-ZIF-8 for Recent Applications

Zeolitic imidazolate frameworks (ZIFs) are interesting materials for use in several aspects: energy storage material, gas sensing, and photocatalysis. The thermal stability and pyrolysis process are crucial in determining the active phase of the material. A deep understanding of the pyrolysis mechanism is in demand. Therefore, the thermodynamics and combustion process with different heating rates was examined, and the kinetic parameters were computed employing thermogravimetric tests. Based on the TG analysis of combustion, pyrolysis moves to the high-temperature region with an increase in heating rate. The decomposition process can be separated into the dehydration (300–503 K) and the pyrolysis reaction (703–1100 K). Three points of the decomposition process are performed by dynamical analysis owing to shifts of slopes, but the combustion process has only one stage. The Zeolitic imidazolate framework’s structure properties were examined using TDDFT-DFT/DMOl3 simulation techniques. Dynamical parameters, for instance, the possible mechanism, the pre-exponential factor, and the apparent activation energy are obtained through comparison using the Kissinger formula. The thermodynamics analysis of the Zn1-xCox-ZIF-8 materials is an effective way to explore the temperature influence on the process of pyrolysis, which can benefit several environment purifications, photocatalyst, and recent applications.

Thermochemical Recycling of Oily Sludge by Catalytic Pyrolysis: A Review

The main methods of treating oily sludge at home and abroad and the current research status of oily sludge pyrolysis technology are briefly described, and four commonly used catalysts are introduced: metals, metal compounds, molecular sieves, metal-supported molecular sieves, and biomass catalysts for oily sludge. The influence of pyrolysis, the pyrolysis mechanism, and the product composition of oily sludge with the addition of different catalysts are also discussed. Finally, the development direction of preparing new catalysts and the mixed use of multiple catalysts is proposed as a theory to provide for the efficient and reasonable utilization of oily sludge.

Progress in Catalytic Pyrolysis of Oil Shale

This paper briefly describes the research status of oil shale pyrolysis technology and the main factors affecting oil shale pyrolysis, with emphasis on four kinds of commonly used catalysts: The effects of natural minerals, metal compounds, molecular sixes, and supported catalysts on the pyrolysis of oil shale were discussed. The changes of the pyrolysis mechanism and product composition of oil shale with the addition of different catalysts were discussed. Finally, the development direction of preparation of new catalysts was discussed, in order to provide a prospect for the development and utilization of unconventional and strategic alternative energy resources around the world.