The thermal degradation of lignocellulose biomass with an acid leaching pre-treatment using a H-ZSM-5/Al-MCM-41 catalyst mixture

Abstract

Improvements on the pyrolysis process of biomass fuels are needed to obtain a high-quality of bio-oil. Pretreatment by acid leaching prior to the pyrolysis process is considered to remove Alkali and Alkaline Earth Metal (AAEM) from the biomass, since AAEM adversely affect the catalytic pyrolysis process. Therefore, the main objective of the present work was to determine and compare the effect of mixed-catalysts consisting of H-ZSM-5 and Al-MCM-41, which are used at different ratios in lignocellulose biomass pyrolysis via Thermal Gravimetric Analysis (TGA) for both, un-leached and leached biomass. In addition, the activation energies have been determined based on the solid-state reaction mechanism. The results from the acid leaching treatment showed that the optimum leaching process was set to 30 min, 30°C and 5 wt% acetic acid in the leaching liquid. This resulted in 59%, 95%, 99%, and 96% reduction degree of Calcium (Ca), Magnesium (Mg), Potassium or Kalium (K), and Natrium (Na), respectively. The Higher Heating Values (HHVs) for un-leached and leached biomass were 19.42 and 19.14 MJ/kg, respectively, calculated by using the Milne formula. The HHV value is not significantly influenced by the acid-leaching pre-treatment. Thermogravimetric analysis showed similar trends for the mass loss as a function of temperature and four stages could be determined from the thermal degradation of biomass. There was no significant shift in the temperature profiles between un-leached and leached biomass degradations. However, the removal of AAEM significantly affected the degradation of hemicellulose, cellulose, and lignin. A 12.4-18.2% increase of mass losses could be found in Phase 2 for leached biomass, compared to un-leached biomass. The mass losses in Phase 2 also increased with increased heating rates. From the un-leached biomass experiments using a catalyst mixture, the percentage of mass loss increased from 64.95 wt% at 10 K min −1 to 68.33 wt% at 50 K min −1 . Moreover, for the leached biomass, it rose from 65.71 wt% at 10 K min −1 to 66.73 wt % at 30 K min −1 , before decreasing to 62.44 wt% at 50 K min −1 . A lower mass loss in Phase 4 for leached biomass compared to un-leached biomass showed the influence of an AAEM removal. The second order (F2) mechanism was able to illustrate the catalytic pyrolysis process, proven by the result that the coefficient of determination (R 2 ) was higher than 0.99, which was high compared to other mechanisms. An acid leaching pretreatment led to a reduction in the activation energies. The activation energies for the un-leached biomass were 26.94 and 25.56 kJ mol −1 at a heating rate of 10 K min −1 for a process without and with a catalyst mixture, respectively. The activation energies for leached biomass were 24.05 and 21.80 kJ mol −1 . The results also showed that the use of the acid leaching process as a treatment prior to catalytic pyrolysis is positive, since it resulted in high devolatilization and reaction rate.

Thermal Performance Analysis of Ionic Liquid‐Pretreated Spent Coffee Ground Using Aspen Plus®

“…The same trend was observed with the higher heating values ( HHV s). Acid leaching pretreatment does not affect the HHV significantly, while on the other hand IL pretreatment increased the HHV value visibly, leading to a good‐quality fuel 27.…”

Recycling Strategy for Bioaqueous Phase via Catalytic Wet Air Oxidation to Biobased Acetic Acid Solution

“…0.5–0.6 wt % C (equivalent to 1.3–1.5 wt % acetic acid) and might be directly recycled in the biobased industry, e.g., for acid leaching (Figure a). Several reports have used a diluted acetic acid solution (e.g., 0.1–1 wt %) to demineralize the biomass prior to torrefaction or fast pyrolysis for a reduction of char yield and an enhanced reactivity of biomass. − In a few works, a higher concentration of acetic acid solution was applied (e.g., 5–10 wt %). , For this application, the diluted bioacetic acid solution could be concentrated by, for example, distillation and nanofiltration membrane …”

Evaluation of Bio-Oils in Terms of Fuel Properties

“…This process produces the following three products: bio-oil, combustible gas, and char [4][5][6]. Among these products, bio-oil is of particular interest because of its potential use as fuel (either directly or after refinement using various methods) [7,8]. It contains chemical compounds that are formed by the thermochemical decomposition of the primary biomass structure, mainly cellulose, hemicellulose, and lignin.…”