Experimental study about the influence of protein in seaweed on furfural production and design of a seaweed-based biorefinery concept
Year: 2015
Type: dissertation
Abstract: In a future industrial system, which will be – in contrast to today – primarily based on sustainable resources, biorefineries will play a key role. Biorefineries are an ideal replacement for petroleum refineries, since they are able to provide a portfolio of different products. Furfural is one of these products and is derived from pentoses in biomass. Furfural yields from biomass are lower if compared with yields from pure xylose. One of the possible explanations is present protein in biomass, whose amino acids may react with sugars (Maillard reaction) preventing thereby the sugar to convert to furfural. The aim of the first part of this research, was to conduct experiments using Palmaria palmata, a seaweed with high xylose and protein content, to evaluate the influence of its protein on the furfural yield. Hence, experiments with Palmaria palmata were conducted, where different amounts of proteins were extracted in aqueous and alkaline solutions prior to the furfural conversion in an autoclave in order to vary the protein content in the seaweed. From the experimental results it was concluded, that Maillard reactions do not occur because of the acidic conditions applied, which lead to the protonation of the amino acids. However, furfural yields significantly increased with a prior protein extraction. Thereupon, the furfural yield was proposed to be influenced by the presence of water-soluble galactose, which is present in Palmaria palmata in considerable quantities. This hypothesis also backs on the observation in research groups, that xylose in the presence of glucose yields less furfural. The second part of this thesis contains the design of a seaweed-based biorefinery concept with co-production of furfural, R-phycoerythrin and syngas and a successive numerical analysis of the plant with Aspen Plus. The furfural reactor of the biorefinery is based on a P&E design, whose main feature is the rapid steam stripping of the formed furfural from the liquid to the vapour phase to prevent the furfural from undergoing further reactions. The reactor was modelled with the RadFrac unit of Aspen Plus and showed an increase in furfural molar yield of 4.1 % to 59.8 % if compared to the same process in a batch reactor. However, the increase in furfural yield is not as high as expected. Other process technologies, such as aqueous two-phase systems, might overcome the problem of low furfural yields. Next to the kinetic model, both the water:biomass ratio of the feed and the steam:biomass ratio influence the behaviour of the biorefinery. A change in water leads to lower yields and purity, because the MTC was designed at its optimum. On the other hand, an increase in water leads to a higher hydrogen production, but, at the cost of energy. When changing the steam:biomass ratio, the biorefinery responses differently. More steam results in higher yields and purity, but at the expense of a lower hydrogen output and a lower energy efficiency of the supercritical water gasification unit as more organic matter is stripped to the distillate stream of the MTC.
Author: Moritz Schulze
Language: English
Subfield: Catalysis
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W830753998