Copyrolysis of Biomass and Coal: A Review of Effects of Copyrolysis Parameters, Product Properties, and Synergistic Mechanisms.

Cui Quan,Ningbo Gao

doi:10.1155/2016/6197867

Abstract

Concerns in the last few decades regarding the environmental and socioeconomic impacts of the dependence on fossil fuels have resulted in calls for more renewable and alternative energy sources. This has led to recent interest in copyrolysis of biomass and coal. Numerous reviews have been found related to individual pyrolysis of coal and biomass. This review deals mainly with the copyrolysis of coal and biomass and then compares their results with those obtained using coal and biomass pyrolysis in detail. It is controversial whether there are synergistic or additive behaviours when coal and biomass are blended during copyrolysis. In this review, the effects of reaction parameters such as feedstock types, blending ratio, heating rate, temperature, and reactor types on the occurrence of synergy are discussed. Also, the main properties of the copyrolytic products are pointed out. Some possible synergistic mechanisms are also suggested. Additionally, several outlooks based on studies in the literature are also presented in this paper.

Highlights

Coal is the most abundant fossil fuel energy source available to the world economy and its reserve was expected to last for up to 200 years compared to about 65 years and 40 years for natural gas and crude oil, respectively
Lacks of synergies are mainly due to the low heating rate used in the thermogravimetric analysis (TG) runs and to the relatively high nitrogen flow rate in the apparatus [50]
Onay et al [11] found that the maximum pyrolysis oil yield reached 39.5% with 5% of lignite mixed with safflower seed during the copyrolysis in a fixed-bed reactor at 550∘C; the pyrolysis oil yield increased by about 17% compared to the expected ones

Summary

Introduction

Coal is the most abundant fossil fuel energy source available to the world economy and its reserve was expected to last for up to 200 years compared to about 65 years and 40 years for natural gas and crude oil, respectively. Compared with plastic wastes and so forth biomass is a perspective source to replace fossil fuels in the future, as it is abundant, renewable, clean, and carbon dioxide neutral Both biomass and coal are carriers of accumulated solar energy. The lack of synergy between the two fuels during copyrolysis is indicated by the linear relationship between the volatile matter release/product yield and the percentage of biomass added to the mixture. Given such a wide range of variables involved, the results obtained by different groups are sometimes conflicting. Some possible synergistic mechanisms during copyrolysis of coal/biomass blends were presented

Copyrolysis Reaction Parameters

Liquid

Environmental Benefits

Possible Synergistic Mechanisms

Findings

Conclusions and Outlook