New Article: Low-temperature torrefaction assisted with solid-state KOH/urea pretreatment for accelerated methane production in wheat straw anaerobic digestion

A new article out of a collaboration between Dr. Ning Yan and Dr. Heyu Chen’s labs has been published in Bioresource Technology Journal written by Zhijiang Shao, Pitchaimari Gnanasekar, Nicole Tratnik, Nicolas R. Tanguy, Xiaohui Guo, Mingqiang Zhu, Ling Qiu, Ning Yan, and Heyu Chen.

You can find the article here.


Low-temperature torrefaction assisted with solid-state KOH/urea applied onto wheat straw was proposed to break down the lignocellulosic material to enhance biomethane production in anaerobic digestion (AD). The optimization of key parameters applying the Box-Behnken design and response surface method showed that an addition of 0.1 g/gstraw KOH/urea at 180 ℃ while torrefying for 30 min was the optimal condition for producing biomethane. Results indicate that co-applying KOH and urea in torrefaction synergistically enhanced the biodegradability of straw by effectively removing lignin and largely retaining cellulose, giving rise to a 41 % increase in the cumulative methane production compared to untreated straw (213 mL/g-volatile solids (VSraw)) from batch AD. Additionally, the nitrogen- and potassium-rich digestates helped to improve soil fertility, thus achieving a zero-waste discharge. This study demonstrated the feasibility of using solid-state KOH/urea assisted low-temperature torrefaction as an effective pretreatment method to promote methane production during AD.