الفهرس 
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Abstract
The conversion of cellulosic biomass to soluble sugars for biofuel production plant has received enormous interest to be used as an alternate and renewable supply of energy. Hemicellulosic biomass is possibly applied to contribute to biofuel production to scale back greenhouse gas emissions and global warming. In this work, Egyptian bagasse was used, and for the first time details studies on hydrolysis of the bagasse was carried out using hydrochloric acid and compared with sulfuric acid. Literature was lacked information of such comparison this work was aimed to fill this gap. Throughout this work, two stages concentrated acid hydrolysis process was used for the hydrolysis of biomass as a biological resource. Each sulfuric and hydrochloric acids were used and applied at the same equivalent concentration (weight by weight) for the hydrolysis process. The impact of acid type on the two stages concentrated acid hydrolysis of biomass has been investigated. The results confirmed that hydrochloric acid is more powerful than sulfuric acid. In the first stage, the results showed that, increasing the sulfuric acid concentration from (10 to 30 %) (wt./wt.), resulted in enhancing xylose concentration from 6.2 to 9.0 mg/ml compared to 9.1 to 12.0 mg/ml in the case of hydrochloric acid (10 to 30 %). additionally, the second stage results showed that glucose concentration increased from 3.1 to 5.2 mg/ml and xylose was slightly accumulated from 1.8 to 2.1 mg/ml, using sulfuric acid (20-30%) and total dissolved sugars increased from 5.2 to 7.7 mg/ml. While in the case of hydrochloric acid (20-30%) for the biomass hydrolysis, total dissolved sugars increased from 6.2 to 8.8 mg/ml. The results confirmed that both acids are effective for the biomass hydrolysis process with higher enhancements (1.25 – 1.7 times) on applying hydrochloric acid.
Two different de-pithed bagasse samples were studied, with the first one is very fine powder that passed mesh No 325 and the second sample is coarse bagasse without milling (3 cm fiber bundle length). The effect of bagasse particle size refining on the
Summary
studied parameters was studied as well as hydrolysis of the two particle sizes were carried out. In the present study, the bagasse material was analyzed and determined by transmission and scanning electron microscopy (TEM and SEM) which confirmed that the particle size after the milling process was decreased to the Nanometer scale form (20 - 50 nm) that catalyzed the hydrolysis process. Hydrolysis time, temperature and liquid to solid ratio were kept constant at 30 minutes in the 1st stage and one hour in the 2nd one, 100 oC and 10:1 respectively, while concentrations of sulfuric acid were varied. In the first stage the acid concentration ranged between 2% to 10% (wt. / wt.) and in the 2nd stage it ranged between 10% to 30 %( wt. /wt.). The results confirmed that on using fine powder bagasse, in the 1st stage acid hydrolysis, the total dissolved sugars were 2 to 1.3 times more than that on using coarse bagasse, based on acid concentrations. Concerning concentration of xylose in the hydrolyzed solution, increasing acid concentration from 2% to 10%, on using coarse bagasse, xylose concentration was increased from 4 to 9.9 mg/ml while on using fine powder bagasse it increased from 7.8 to 12.9 mg /ml. Noticing that in the second stage, by using fine powder bagasse the total dissolved sugars were 1.7 times more than on using coarse bagasse. As regards of xylose concentration in the hydrolyzed solution, on increasing the acid concentration from 10% to 30%, the increase was from 0.7 to 1.8 mg/ml on using coarse bagasse, whereas on using fine powder bagasse the increase was from 1 to 2.3 mg /ml. The higher efficiency of fine powder bagasse may be associated to that; the mechanical action can promote degradation and damage of lignocellulose internal structure and destroy the crystalline structure of biomass, additionally generation of higher surface area of the biomass particles. Such actions increase accessibility and mass transfer of acid that result in higher hydrolysis of both hemicellulose and cellulose.
Keywords: biomass, hydrolysis, sulfuric acid, hydrochloric acid, dilute acid hydrolysis.