Ethanol production from various agricultural and forest residues has been widely researched, but there is limited information available on the use of mixed hardwood for ethanol production. The main objective of this study is to assess the impact of time on the steam explosion pretreatment of waste wood (mixed hardwood) and to determine the convenience of a delignification step with respect to the susceptibility to enzymatic hydrolysis of the cellulose residue and the recoveries of both cellulose and hemicellulosic sugars. Delignification did enhance enzymatic hydrolysis yields of steam exploded waste wood. For steam explosion pretreatment times of 3 and 5 min, the recovery yield of hemicellulosic-derived sugars decreased. The effective hemicellulose solubilization does not always result in high recoveries of hemicellulose-derived sugars in the liquid fractions due to sugar degradation. In the steam explosion pretreatment times of 3 and 5 min, where hemicellulose solubilization exceeded 95%, but sugar recoveries in the liquid fraction remained below 30%. Cellulose to glucose yield losses were less significant than hemicellulosic-sugar losses, with a maximum loss of 24% at 5 min. Up to 80% of the lignin in the original wood was solubilized, leaving a cellulose-rich residue that led to a concentrated cellulose to glucose yield solution (about 50 g/L after 72 h enzymatic hydrolysis in the best case). The maximum overall process yield, taking into account both sugars present in the liquid from steam explosion pretreatment and cellulose to glucose yield from the steam exploded, delignified and hydrolyzed solid was obtained at the lowest steam explosion pretreatment time assayed.

Populus euramericana is emerging as a viable feedstock for producing bioethanol from renewable resources. Steam explosion pretreatment of P. euramericana can solubilize a significant portion of the hemicellulosic component and enhance the glucose conversion of the remaining cellulose for fermentation into ethanol. In this study, steam explosion condition of P. euramericana is performed in a steam explosion reactor at severity log Ro 4.02 and severity log Ro 4.37. Glucose conversion varied from 72.3% to 80.1% of steam exploded P. euramericana at severity log Ro 4.02 and severity log Ro 4.37. Ethanol yields(%) based on sugar content after enzymatic hydrolysis after 48 h fermentation ranged from 87.0% to 88.4%. As a result, from 100 g of raw material, 14.0 g of ethanol are recovered of 47.3 g available cellulose content. This research of steam explosion pretreatment was a promising method to improve glucose conversion and ethanol yield for bioethanol production.

The ex-vessel steam explosion may occur when, during a severe reactor accident, the molten core pours into the water in the reactor cavity. These dynamic loads on the cavity wall could potentially lead to the significant failure of the cavity wall. But the phenomenon like this steam explosion includes big uncertainty in estimating the impulsive pressure loading of RCB. In this study, risk based integrity assessment method of the NPP structure subjected to steam explosion load was suggested to capture these uncertainties involved during the structural integrity assessment of the Nuclear power plant.