The influence of process temperature on structural characteristics of the obtained hydrochars

Abstract

In recent years, a technique for conversion of waste biomass into solid carbon material (hydrochar) with high energy potential, become very attractive. This process is known as hidrothermal carbonization (HTC). The conversion of raw biomass into the hydrochars is called "wet" pyrolysis since conversion take place at moderate 1 temperatures and pressures, while subcritical water is used as the process medium. Major influences on the structure of the obtained product have different process parameters such as pressure, temperature, reaction time, biomass type and biomass and water ratio. Based on the literature review, it can be concluded that the temperature has the greatest influence on the structural changes of the obtained hydrochars and therefore stands out as the most important parameter of the HTC process. It has been shown that increasing of reaction temperature increases the degradation of biomass, thus the yield, ash and volatile content in the resulting hydrochars is reduced. On the other hand, the carbon content, fuel properties and energy density are increased. This suggests that temperature variation during the HTC process provides hydrochars with improved fuel characteristics in relation to the feedstock, whereby the utilization value of waste biomass was significantly improved. This is the first report of HTC conversion of waste substrates for mushrooms cultivation and comparison of obtained results with literature data.