Development and economic analysis of bioethanol production facilities using lignocellulosic biomass.

An integrated process for bioethanol production from Miscanthus sacchariflorus was used to construct a bench-scale plant constructed and an economic analysis was carried out to investigate the feasibility of its application to a commercial plant. The bench-scale plant was operated for 1 month and an economic analysis and sensitivity analysis was performed on the data acquired. In this study, 100,000 kL of bioethanol could be produced annually from 606,061 tons of M. sacchariflorus and the production cost was calculated to be US$1.76/L. However, the by-products of this process such as xylose molasses and lignin can be sold or used as a heat source, which can decrease the ethanol production costs. Therefore, the final ethanol production cost was calculated to be US$1.31/L, and is considerably influenced by the enzyme cost. The results and data obtained should contribute to the development of a commercial-scale lignocellulosic bioethanol plant.

Effects of NH4Cl and MgCl(2) on pretreatment and xylan hydrolysis of miscanthus straw.

This study investigated the effects of NH(4)Cl and MgCl(2) on pretreatment and xylan hydrolysis of miscanthus straw for biofuels production. It was observed that increasing the pretreatment temperature decreased the remaining solid, increased the enzymatic digestibility, and increased the xylan removal. When 0.2-5.0% NH(4)Cl and MgCl(2) were employed in pretreatments, increasing the inorganic salt concentration slightly diminished the remaining solid, though the enzymatic digestibility was enhanced. Under the higher-than-2% condition, no xylan remained in the solid residues after pretreatment. With pretreatment time, the remaining solid slightly decreased, but the enzymatic digestibility was increased. Moreover, xylan removal was linearly increased to 15 min, after which it was completely hydrolyzed. Overall, these results indicated that pretreatment by 2% NH(4)Cl or MgCl(2) at 185 °C for 15 min completely hydrolyzes the xylan of miscanthus straw. In scanning electron microscopy (SEM) images, the physical surface of the miscanthus straw showed an apparently damaged surface area and exposure of the internal structure after pretreatment with NH(4)Cl and MgCl(2) by SEM.

Effects of inorganic salts on pretreatment of Miscanthus straw.

This study focused on the effects of five inorganic salts, NaCl, KCl, CaCl2, ZnCl2, and FeCl3, on the pretreatment of Miscanthus straw for sugar recovery and enzymatic digestibility. In the results, all of the salts reduced the hemicellulose content in the straw. Most notably, FeCl3 effected almost 100% xylan removal. Overall, the trivalent salts, which include FeCl3, had an especially significant influence on enzymatic digestibility of Miscanthus straw compared with the di- and mono-valent inorganic salts, which had relatively only minor effects. The salt impacts were in the following order: FeCl3>ZnCl2>CaCl2>KCl>NaCl. Under the pretreatment condition of 0.5% FeCl3 at 200°C for 15min, 100% xylan removal and 71.6% enzymatic digestibility were obtained. Nevertheless, ZnCl2 get the better effect on total glucose content than that of FeCl3.

Rapeseed-straw enzymatic digestibility enhancement by sodium hydroxide treatment under ultrasound irradiation.

In this study, we carried out sodium hydroxide and sonication pretreatments of rapeseed straw (Brassica napus) to obtain monosugar suitable for production of biofuels. To optimize the pretreatment conditions, we applied a statistical response-surface methodology. The optimal pretreatment conditions using sodium hydroxide under sonication irradiation were determined to be 75.0 °C, 7.0 % sodium hydroxide, and 6.8 h. For these conditions, we predicted 97.3 % enzymatic digestibility. In repeated experiments to validate the predicted value, 98.9 ± 0.3 % enzymatic digestibility was obtained, which was well within the range of the predicted model. Moreover, sonication irradiation was found to have a good effect on pretreatment in the lower temperature range and at all concentrations of sodium hydroxide. According to scanning electron microscopy images, the surface area and pore size of the pretreated rapeseed straw were modified by the sodium hydroxide pretreatment under sonication irradiation.

Pretreatment of rapeseed straw by soaking in aqueous ammonia.

Pretreatment of lignocellulosic biomass has gained attention for production of biofuels. In this study, pretreatment by soaking in aqueous ammonia was adopted for pretreatment of biomass for ethanol production. A central composite design of response surface methodology was used for optimization of the pretreatment condition of rapeseed straw, with respect to catalyst concentration, pretreatment time, and pretreatment temperature. The most optimal condition for pretreatment of rapeseed straw by soaking in aqueous ammonia was 19.8% of ammonia water, 14.2 h of pretreatment time, and a pretreatment temperature of 69.0 °C. Using these optimal factor values under experimental conditions, 60.7% of theoretical glucose was obtained, and this value was well within the range predicted by the model. SEM results showed that SAA pretreatment of rapeseed straw resulted in increased surface area and pore size, as well as enhanced enzymatic digestibility.

Pretreatment of rapeseed straw by sodium hydroxide.

Pretreatment method for rapeseed straw by sodium hydroxide was investigated for production of bioethanol and biobutanol. Various pretreatment parameters, including temperature, time, and sodium hydroxide concentration were optimized using a statistical method which is a central composite design of response surface methodology. In the case of sodium hydroxide pretreatment, optimal pretreatment conditions were found to be 7.9% sodium hydroxide concentration, 5.5 h of reaction time, and 68.4 °C of reaction temperature. The maximum glucose yield which can be recovered by enzymatic hydrolysis at the optimum conditions was 95.7% and the experimental result was 94.0 ± 4.8%. This experimental result was in agreement with the model prediction. An increase of surface area and pore size in pretreated rapeseed straw by sodium hydroxide pretreatment was observed by scanning electron microscope.