Torrefaction of Barley Straw for the Co-Production of Energy and Adsorbent Materials

Abstract

The purpose of this study was first to examine and then to maximize, the adsorbency of torrefied barley straw, in order to remove basic dyes like Methylene Blue (MB) from wastewater. On the other hand, the effect of the torrefaction process on the heating value of the material was investigated. Moderate modification conditions (220 ºC, 20 min) were found to maximize adsorbency of modified barley straw. The experimental data were simulated by a pseudo-second order kinetic model. The torrefaction also significantly enhanced the higher heating value of the pretreated barley straw compared to the untreated material. Specifically, the calorific value increased from 16.1 MJ/kg to 19.4 MJ/kg for sample torrefied at 240 ºC during 40 min. Consequently, the torrefaction of barley straw leads to the coproduction of material with enhanced energy content in combination with improved adsorption capacity. The coproduction of energy and adsorbents from lignocellulosic biomass takes into account (i) the biorefinery (more than one product) and (ii) the Industrial Ecology concept (using solid waste to clean wastewater pollution).

Torrefaction of Agricultural and Wood Waste: Comparative Analysis of Selected Fuel Characteristics

“…The high heating values of raw and torrefied biomasses at varied torrefaction operating conditions are presented in Table 1. In case of raw biomass, the HHV of wood waste i.e., 19.91 MJ•kg −1 was slightly higher than those of agricultural wastes i.e., 18.83 MJ•kg −1 for BS and 18.12 MJ•kg −1 for CS. As expected, the HHV of the torrefied biomass increased with increasing torrefaction temperature.…”

“…Torrefied biomass can also be used as a feedstock in the pyrolysis [16] and gasification [17] processes. Additionally, torrefied biomass also can be used as adsorbent [18][19][20][21] and for soil amendment [22,23]. The yield of torrefied biomass depends on the operating temperature and residence time.…”

“…Previously, Manouchehrinejad et al [24] observed a torrefied biomass yield of 84.69 and 56.46 wt.% for torrefaction temperature of 250 and 290 • C, respectively, for wood waste. The solid yield from torrefied agricultural waste (barley straw) at 200-240 • C during 20-60 min was in the range of 50.1-90.1% [19].…”

Conversion of biomass to biofuels and life cycle assessment: a review

“…Commercially, the torrefaction process is a potential scenario to be applied in various applications. Salapa et al revealed the high adsorption capacity of torrefied barley straw of 11.65 mg/g at operating parameters of 220 °C and 20 min (Salapa et al 2018). Other researchers evaluated the torrefaction process's impacts at different contact periods (i.e.…”