“…% significantly increased exothermic nature of the hydrothermal reactions above 200 ºC (Ibbett et al, 2011). HTT process has been applied in various reactor systems such as stirred batch vessel systems (Weil et al, 1998;Gomez et al, 2015), stationary flow-through systems Torres-Mayanga et al, 2019) or in continuous mode with screw systems (Heitz et al, 1991;Monschein and Nidetzky, 2016), plug flow systems (Thompson and Grethlein, 1979;Church and Wooldridge, 1981;Brennan et al, 1986), while using direct steam injection, conductive or microwave heating (Roos et al, 2009). The process can be conducted with water mainly the liquid phase, such as in stirred (Gomez et al, 2015) or unstirred batch vessels , or in single phase steam (Stephen Glen Allen et al, 2001), or in mixed liquid water and vapour phase such as in steam explosion (Brownell and Saddler, 1987;Bayer, 2007;Roos et al, 2009;.…”