Glucose Recovery from Different Corn Stover Fractions Using Dilute Acid and Alkaline Pretreatment Techniques

Background: Limited availability of corn stover due to the competing uses (organic manure, animal feed, bio-materials, and bioenergy) presents a major concern for its future in the bio-economy. Furthermore, biomass research has exhibited different results due to the differences in the supply of enzymes and dissimilar analytical methods. The effect of the two leading pretreatment techniques (dilute acid and alkaline) on glucose yield from three corn stover fractions (cob, stalk, and leaf) sourced from a single harvest in Uganda were studied at temperatures 100, 120, 140, and 160 °C over reaction times of 5, 10, 30, and 60 min. Results: From this study, the highest glucose concentrations obtained from the dilute acid (DA) pretreated cobs, stalks, and leaves were 18.4 g/L (66.8% glucose yield), 16.2 g/L (64.1% glucose yield), and 11.0 g/L (49.5% glucose yield), respectively. The optimal pretreatment settings needed to obtain these yields from the DA pretreated samples were at a temperature of 160 °C over an incubation time of 30 min. The highest glucose concentrations obtained from the alkaline (AL) pretreated cobs, stalks, and leaves were 24.7 g/L (81.73% glucose yield), 21.3 g/L (81.23% glucose yield), and 15.0 g/L (51.92% glucose yield), respectively. To be able to achieve these yields, the optimal pretreatment settings for the cobs and stalks were 140 °C and for a retention time of 30 min, while the leaves require optimal conditions of 140 °C and for a retention time of 60 min. Conclusions: The study recommends that the leaves could be left on the field during harvesting since the recovery of glucose from the pretreated cobs and stalks is higher

A kinetic study on the decomposition of 5-hydroxymethylfurfural into levulinic acid

Levulinic acid (LA), accessible by the acid catalyzed degradation of biomass, is potentially a very versatile green intermediate chemical for the synthesis of various (bulk) chemicals for applications like fuel additives, polymers, and resin precursors. We report here a kinetic study on one of the key steps in the conversion of biomass to levulinic acid, i.e. the reaction of 5-hydroxymethylfurfural (HMF) to levulinic acid. The kinetic experiments were performed in a temperature window of 98–181 °C, acid concentrations between 0.05–1 M, and initial HMF concentrations between 0.1 and 1 M. The highest LA yield was 94% (mol/mol), obtained at an initial HMF concentration of 0.1 M and a sulfuric acid concentration of 1 M. The yield at full HMF conversion is independent of the temperature. An empirical rate expression for the main reaction as well as the side reaction to undesired humins was developed using the power law approach. Agreement between experimental and model data is good. The rate expressions were applied to gain insights into optimum process conditions for batch processing.

Kinetic Study on the Acid-Catalyzed Hydrolysis of Cellulose to Levulinic Acid

A variety of interesting bulk chemicals is accessible by the acid-catalyzed hydrolysis of cellulose. An interesting example is levulinic acid, a versatile precursor for fuel additives, polymers, and resins. A detailed kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid is reported in this paper. The kinetic experiments were performed in a temperature window of 150-200 °C, sulfuric acid concentrations between 0.05 and 1 M, and initial cellulose intakes between 1.7 and 14 wt %. The highest yield of levulinic was 60 mol %, obtained at a temperature of 150 °C, an initial cellulose intake of 1.7 wt %, and a sulfuric acid concentration of 1 M. A full kinetic model covering a broad range of reaction conditions was developed using the power-law approach. Agreement between the experimental data and the kinetic model is good. The kinetic expressions were used to gain insights into the optimum process conditions for the conversion of cellulose to levulinic acid in continuous-reactor configurations. The model predicts that the highest obtainable levulinic acid yield in continuous-reactor configurations is about 76 mol %, which was obtained when using reactors with a large extent of backmixing.

A kinetic study on the conversion of glucose to levulinic acid

Levulinic acid has been identified as a promising green. biomass derived platform chemical. A kinetic study oil one of the key steps in the conversion of biomass to levulinic acid, i.e., the acid catalysed decomposition of glucose to levulinic acid has been performed. The experiments were Performed in a broad temperature window (140-200 degrees C), using sulphuric acid as the catalyst (0.05-1 M) and a initial glucose concentration between 0.1 and 1 M. A kinetic model of the reaction sequence was developed including the kinetics for the intermediate 5-hydroxymethyl-2-furaldehyde (HMF) and humins byproducts using a power-law approach. The yield of levulinic acid is favoured in dilute glucose solution at high acid concentration. On the basis of the kinetic results, continuous reactor configurations with a high extent of back-mixing are preferred to achieve high levulinic acid yields

Research Progress on Furfural Residues Recycling: A Literature Review

Millions of tons of furfural residues from the furfural industry are produced every year in China. Proper recycling of these residues is highly desirable as it may reduce associated environmental problems and increase the economic viability of the furfural industry. Research progress on furfural residues recycling is reviewed. The residues have high potential for agricultural applications such as organic fertilizers, soil conditioners, artificial soil and culture media, as well as for the production of activated carbon, bioenergy, and for biobased chemicals such as ethanol.