Lignin Extraction Processes

Pulping process Tree species Cellulose (%) Hemicellulose (%) Lignin (%) Extractives (%) ... 

Palm Fiber. Palm press fiber or pericarp fiber includes not only palm press fiber from the oil extraction process but also empty fruit bunches and kernel shells. Its high fiber and lignin content, comparable to wood, and low palatability limit its use in animal feed (55). It exhibits very slow digestion in the bovine rumen such that processing to increase its nutrient content is required prior to use (59). Supplementation with molasses, urea, and vitamins allows palm press fiber to be... 

Biomass is composed of various components such as cellulose, hemicellulose, lignin, extractives and mineral water. The composition of biomass plays a definitive role in altering the product distribution and their properties [2-3J. As is shown in earlier publications [4-S] different biomass, on pyrolysis, give different product yield with different product properties. In order to choose a biomass for a particular process (carbonisation, liquefaction, gasification or adsorbent char) knowledge on the product distribution and properties for various biomass are essential. 

Fiber complexes of ten tobacco cultlvars as byproducts of the leaf protein extraction process contain levels of neutral and acid detergent fiber comparable to that of alfalfa fiber and in excess of that in wheat bran. Compositional analyses revealed lesser concentrations of cellulose, lignin, and lipid but a greater amount of hemlcellulose in tobacco than in alfalfa. In reference to wheat bran, tobacco fiber has comparable amounts of Na, P, S,... 

Proper extraction process needs special requirements to fractionate a certain hemicellulose or mixture of hemicelluloses. However, the presence of lignin network as well as ester and ether lignin-carbohydrate linkages limits the hemicellulose extraction... 

Figure 5.11 shows the principles of the high-pressure hydrothermolysis (HPH) process for lignin extraction and the concept to realize it for experiments with various types of biomass... 

These polymers are also constituents of wood (about 25-30%). It is uncertain what the molecular weights of the polymers are as the materials are quite complex in structure. The extraction processes of lignins result in considerable loss of molecular weights. The structures of lignins vary, depending upon the source. Generally, they are polymers of coniferyl alcohol ... 

Sulfolane, another highly polar solvent, is used to separate aromatic hydrocarbons from aliphatic hydrocarbons [10]. The extraction process first developed by Shell Oil in 1959 and which is referred to as the Sulfolane process is used worldwide. The solvency of sulfolane for certain fatty acids and fatty acid esters is the basis for upgrading animal and vegetable fatty acids used in food products, paints, plastics, resins, and soaps. Aqueous solutions containing 30-70 wt% sulfolane are used to remove lignin from wood chips [11]. Sulfolane is used to remove acidic components like hydrogen sulfide and carbon dioxide from gas feed stocks. 

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