Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance.

Muhammad Khalid Rafiq,Muhammad Tariq Rafiq,Robert Thomas Bachmann,Zhanhuan Shang,Stephen Joseph,Ruijun Long,Jie Zheng

doi:10.1371/journal.pone.0156894

Muhammad Khalid Rafiq, Muhammad Tariq Rafiq + Show 5 more

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https://doi.org/10.1371/journal.pone.0156894

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Abstract

This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario.

Highlights

Sustainable economic development, food security and environmental management are some of the highest priorities of the modern world as these are concerned with the present and future generations
The degree of carbonization for biochar was accelerated with increasing pyrolysis temperature from 300°C, 400°C to 500°C
The results show that corn stover biochar has significantly greater lower heating value (LHV) than corn feed stock on dry basis

Summary

Introduction

Sustainable economic development, food security and environmental management are some of the highest priorities of the modern world as these are concerned with the present and future generations. Vegetables Apples Tomatoes Paddy Cotton Potatoes Corn Wheat. In December 2009, China’s State Council declared that the country aims to reduce its 2005 carbon emissions by 40 to 45% in year 2020. If successful, this would have a considerable positive impact for China and the rest of the world. [4] Some of the main commodities produced include rice paddy, vegetables, tomato, apples, wheat, potato and corn accounting for 18 to 59% of the world’s production (Table 1). Corn is one of the main crops cultivated in China and production accounts for 24% in the world (Table 1). Wheat, potatoes and cotton, corn belongs to C4 plants characterized by a higher yield potential, lower erosion-index, better CO2 reduction rates and need for less fertilizer, water and chemicals.[8]

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