Selecting Catalysts for Pyrolysis of Lignocellulosic Biomass

Abstract

The pyrolysis of lignocellulosic biomass is a promising technology for obtaining renewable chemicals and fuels to replace fossil-based products. However, due to the complexity of the lignin, cellulose and hemicellulose molecules, a large variety of compounds are often formed, making commercial implementation difficult. The use of a catalyst during reactions has been recognized as one of the major improvements in pyrolysis, allowing the production of selected compounds. Moreover, the large number of available catalysts opens up a wide range of possibilities for controlling the reaction network. Zeolites, hierarchical zeolites, alkali and alkaline earth oxides, transition metals and carbonaceous materials, among others, have been investigated in the pyrolysis of a variety of biomasses. In addition, bifunctional catalysts play a role in pyrolysis, as well as the addition of plastics as hydrogen donors. This review aims to present and discuss in detail state-of-the-art catalytic pyrolysis, focusing on the relationships between the properties of the catalysts and the obtained products. A guideline for selecting catalysts for lignocellulosic biomass is also provided.

A review on thermochemical based biorefinery catalyst development progress

“…Zeolites are the most popular group of catalysts, which have been tested in the pyrolysis of biomass. 196,197 They are very active for cracking and dehydration reactions and can remove the non-desirable species such as carboxylic acids, phenolics, ethers, esters, etc. from bio-oil.…”

Algae: Nature’s Renewable Resource for Fuels and Chemicals

“…The amount of hemicellulose and lignin present in the pyrolysis feedstock significantly affects degradation reactions, consequently affecting product yields and compositions. The presence of a lower amount of hemicellulose in the mixture leads to less secondary cracking reactions and free radical formations, lowering non-condensable gas formation [70,71]. A higher amount of lignocellulosic material presence in the feedstock promotes secondary cleavage reactions, such as cleavage of methoxy groups present in lignin, enhancing gas yield [4].…”

Catalytic Pyrolysis of Lignin from Residual Red Liquor

“…The presence of the metal catalyst resulted in a notable increase in the production of aromatic compounds compared to non-catalytic pyrolysis. This can be attributed to the abundance of active sites provided by the catalyst, facilitating enhanced deoxygenation of the bio-oil and subsequent hydrocarbon formation [16]. The catalyst employed in this experimental study consists of nickel supported on alumina, prepared using the impregnation method.…”