Как выбрать гостиницу для кошек
14 декабря, 2021
Ethanol production from lignocellulosic biomass has to include a pretreatment more intensive than those used in processing sugar and starch-rich biomass in order to release the sugar compounds contained in the biomass. Agricultural residues like wheat straw or other types of biomass derived from plant material contain lignin, which is constructed to resist microbial attack and to add strength to the plant. Pretreatments are used to open the biomass by degrading the lignocellulosic structure and by partially hydrolysing the substrate. Current pretreatment methods, however, contribute to 30-40% of the total costs of bioethanol production from lignocellulosic biomass. The National Renewable Energy Laboratories (NREL) estimates that in an Nth generation plant (mature technology), feedstock handling and pretreatment would account for approximately 20% of the total ethanol production costs [15].
Several pretreatment methods have been developed [16] (see also Zac — chi, this volume). However, in all methods the biomass concentrations need to be higher than 20% dry weight to ensure a suitable ethanol concentration for the subsequent distillation process. A new patented pretreatment process, Wet-ox explosion (WE), has been developed in our laboratory combining steam-explosion and wet oxidation using small amounts of oxygen [17]. The optimal combination of process parameters such as temperature (170-200 °C), pressure (12-30 bar), amount of oxygen addition, and residence time (2-15 min) has been tested. Depending on the biomass material used, the method will yield variable sugar yields but overall the results show that the method will be efficient and cost-effective for opening of most major biomass materials such as straw, corn stover, bagasse, and woody materials. Table 1 shows the apparent advantages and disadvantages of this pretreatment method.
Table 1 Advantages and disadvantages of Wet-Ox-Explosion
Disadvantages
Fast and efficient Requires water supply
No emission products Advanced technology
Low heat consumption No standard equipment
No detoxification Only tested on pilot scale
Easily convertible substrates No waste products