Catalytic Hydrothermal Liquefaction Article Critique Assignment (Article Critique Sample)

Autohydrolysis of Hardwoods
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Autohydrolysis of Hardwoods
This article from Elsevier explores the kinetics as well as mechanisms involved in the autohydrolysis of the hardwoods. The process of autohydrolysis uses water and is a promising technology especially in the extraction of hemicellulose from the hardwoods before production of pulp (pulping). The autohydrolysis process produces pulp alongside other vital co-products such as acetic acid and ethanol. This article explains the process used in performing kinetic and mechanism analysis for autohydrolysis using the continuous mix flow reactor. The article contrasts its analysis with the previous work by other researchers who have been using the batch reactors in the analysis of the kinetics and mechanisms in autohydrolysis. In the study by (Lawoko & Heiningen, 2010) the hardwood chips are reserved in the basket secured in the reactor. The study used a well-modeled reactor that was efficient in determining the intrinsic kinetics of the hemicellulose dissolution. The reactor allowed a quick elimination of the dissolved products. Therefore, there are minimal chances of the degradation as well as further hemicellulose hydrolysis inside the solution. The rate of xylan removal assumes an S-shaped pattern. The GPC analysis for the constant extract elimination shows that dissolved xylan oligomers CITATION Mar102 \l 2057 (Lawoko & Heiningen, 2010) indicates a lesser DP than nearly 25. The lignin withouth xylan oligomers, as well as the oligomers of cellulose, constitute the main composition in the dissolved materials at the initial autohydrolysis stage. However, the xylan-lignin (covalently bonded) makes the major compound eliminated during the later autohydrolysis stage. The molecular weight of the dissolved compounds reduces with time during the 2nd autohydrolysis stage.
There has been an increase in the price of the fuel all over the world. The biofuels have been perceived as one of the most promising solutions to the fuel and energy crisis. However, the conversion of woody biomass into usable biofuel has been regarded as one of the most challenging issues. Mainly, the conversion of the structural polysaccharides into fermentable simple sugars (monosaccharides) has been quoted as the major challenge. The autohydrolysis technique gives a glimpse to the promising technology for cheaper, safe and efficient production of biofuel as well as the pulp. In the process, the only solvent used is steam water. Therefore, the process is cheap and environmentally friendly. Moreover, the acetic acid is formed as a co-product of the pulp. The ethanoic acid is created from the O-acetyl groups found in the polysaccharides CITATION Mar102 \l 2057 (Lawoko & Heiningen, 2010) such as cellulose, and it is significant in lowering the pH of the dissolved extract.
The authors outline a simple and precise experiment for analyzing kinetics and mechanism for the autohydrolysis of the hardwoods. The raw materials used in the experiment is a combination of southern hardwood chips obtained from 15% maple, , 35% oak, 3% southern magnolia ,12% sycamore and poplar, and 35% sweet & black gum. After air-drying the chips, the continuous mixed batch system was used extraction of the products. The lignin extraction followed a zero or...