Optimization of the Reaction Conditions for Catalytic Fast Pyrolysis of Pretreated Lignin over Zeolite for the Production of Phenol

Abstract

The catalytic fast pyrolysis of lignin for the production of phenols over commercial zeolites was studied in‐depth. The results show that the production of phenols depended on several parameters, such as lignin pretreatment methods, pyrolysis temperature, zeolite structure and acidity, pyrolysis time, and feed‐to‐catalyst weight ratio. Lignin pretreatments had a significant influence on the liquid‐product distribution. Hydrogen chloride pretreatment of lignin increased the depolymerization of the lignin matrix, resulting in an increase of the liquid yield, as well as the phenol fraction. High temperature (e.g., 650 °C) and a fast heating rate (20 °C ms−1) were required to depolymerize lignin and increase the yield of liquid products, and large‐pore‐size zeolites (e.g., FAU) with Si/Al of approximately 15 favored the formation of phenols. A long pyrolysis time (20 s) was also beneficial for phenol to desorb from the catalyst. The medium feed‐to‐catalyst weight ratio of approximately 1:1 prevented further conversion of phenols to deoxygenated products such as aromatic hydrocarbons (benzene, toluene, and xylene).

Optimization of Lignin Extraction from Pine Wood for Fast Pyrolysis by Using a γ-Valerolactone-Based Binary Solvent System

“…550, 650, 750 and 850 °C) were used to evaluate the fast pyrolysis of GVL-lignin from pine wood using a heating rate of 20 °C/ms and residence time of 20 s. The pyrolysis products can be divided into three phases, namely liquid (bio-oil), solid (char) and gas. [41][42][43][44][45][46][47][48] Figure 1A illustrates the yields of liquid, char and gaseous products as a function of the pyrolysis temperature of GVL-lignin obtained using a mixture of 4/1 GVL/H 2 O (w/w) and 0.075 M sulfuric acid at 160 ºC for 24 h. The liquid fraction increased from 550 to (650-850) °C, because of an increase in primary decomposition of lignin at higher temperatures. 49,50 In contrast, the char yield decreased from 550 to (650-850) °C.…”

“…39,40 In addition, fast pyrolysis can be developed under catalytic and non-catalytic conditions, which together with the process conditions, determine the products distribution. [41][42][43][44][45] In this study, pine wood (softwood) was employed as the lignocellulosic biomass source for lignin extraction with GVL/H 2 O solvent in the presence of sulfuric acid. The influence of extraction conditions (i.e.…”

Visualization of Structural Changes During Deactivation and Regeneration of FAU Zeolite for Catalytic Fast Pyrolysis of Lignin Using NMR and Electron Microscopy Techniques

“…The reaction conditions for catalytic fast pyrolysis of pretreated lignin were optimized in a previous study . The results show that a higher amount of catalyst leads to the production of higher amounts of liquid at long pyrolysis times (Figure S1 in the Supporting Information).…”

“…The isotropic chemical shift δ iso as well as the second‐order quadrupolar interaction parameter P Q of each aluminum species was deduced from the position of the signals in the 2D MQ spectrum according to the following [Eqs. (1) and ]:,, …”

Catalytic Fast Pyrolysis of Kraft Lignin over Hierarchical HZSM-5 and Hβ Zeolites

“…Non-CFP of lignin mainly produces oxygen-containing species with very few aromatic hydrocarbons. During the process of lignin pyrolysis, Bokhoven verified that depolymerized lignin products undergo successive reactions to form phenol alkoxy ketones, phenol alkoxy, phenols, aromatic alkoxy, and, finally, aromatic hydrocarbon [14,15]. The presence of zeolites greatly changed the composition of pyrolysis products, leading to improved deoxygenation of the high oxygen-containing compounds into aromatics.…”