Fast Pyrolysis of Four Lignins from Different Isolation Processes Using Py-GC/MS

Xiaona Lin,Jianping Sun,Shujuan Sui,Shun Tan,Zhijun Zhang,Charles Pittman

doi:10.3390/en8065107

Xiaona Lin, Jianping Sun + Show 4 more

Open Access

https://doi.org/10.3390/en8065107

Copy DOI

Abstract

Pyrolysis is a promising approach that is being investigated to convert lignin into higher value products including biofuels and phenolic chemicals. In this study, fast pyrolysis of four types of lignin, including milled Amur linden wood lignin (MWL), enzymatic hydrolysis corn stover lignin (EHL), wheat straw alkali lignin (AL) and wheat straw sulfonate lignin (SL), were performed using pyrolysis gas-chromatography/mass spectrometry (Py-GC/MS). Thermogravimetric analysis (TGA) showed that the four lignins exhibited widely different thermolysis behaviors. The four lignins had similar functional groups according to the FTIR analysis. Syringyl, guaiacyl and p-hydroxyphenylpropane structural units were broken down during pyrolysis. Fast pyrolysis product distributions from the four lignins depended strongly on the lignin origin and isolation process. Phenols were the most abundant pyrolysis products from MWL, EHL and AL. However, SL produced a large number of furan compounds and sulfur compounds originating from kraft pulping. The effects of pyrolysis temperature and time on the product distributions from corn stover EHL were also studied. At 350 °C, EHL pyrolysis mainly produced acids and alcohols, while phenols became the main products at higher temperature. No obvious influence of pyrolysis time was observed on EHL pyrolysis product distributions.

Highlights

Concerns over future fossil fuel depletion and current global warming have led to an increasing interest in converting biomass into biofuels [1]
The low decomposition temperature of wheat straw alkali lignin (AL) was most likely promoted by the catalytic effect of sodium derived from the isolation process [21]
The Wheat Straw sulfonate lignin (SL) lignin shows a vast weight decrease at relatively low temperatures due to its high sulfur and carboxylic group content, which can both readily decompose to form gases (e.g., SO2 and CO2). These four lignin types displayed markedly different thermal degradation behaviors, a result of their different structures and compositions when isolated by different processes

Summary

Introduction

Concerns over future fossil fuel depletion and current global warming have led to an increasing interest in converting biomass into biofuels [1]. Biomass-derived fuels are renewable because the CO2 released from their combustion can be recycled into the replacement plants by photosynthesis [2]. Lignin is a major component of biomass. It is a three-dimensional amorphous polymer consisting of methoxylated phenylpropane structures [3]. It is the major renewable aromatic resource and its chemical structure and abundance varies with its source species [4]. Abundant industrial lignin is obtained as by-product from pulping and enzymatic hydrolysis or fermentation processes [5]

Methods

Results

Conclusion