Effect of torrefaction temperature on energy properties of spent coffee groundNatthanant Bangkha, Wanphut Saechua, Tharathip Nuamyakul and Jiraporn Sripinyowanich JongyingcharoenE3S Web Conf., 187 (2020) 03009DOI: https://doi.org/10.1051/e3sconf/202018703009