Ethylene glycol solution allows to fractionation of agricultural crop residues into pulps and valuable by-products. Many no-wood materials, such as vine shoots, cotton stalks, leucaena (Leucaena leucocephala) and tagasaste (Chamaecytisus proliferus) [152, 153], palm oil tree residues [140] as well as waste newspaper [154], were subjected to ethylene glycol fractionation or pulping to obtain pulp or cellulose-rich fraction for the production of ethanol. In addition, ethylene glycol was used as modifying agents in soda [141] and kraft puilping [155], aimed at improving physical and mechanical properties of the paper sheets.

A new process has been designed to fractionation of agricultural crop residues (palm oil empty fruit bunches—EFB) for the production of pulp, lignin and he — micelluloses [140]. The obtained EFB organosolv pulp was used to produce paper, and the final properties of the resulting paper sheets were improved after refining. The black liquor showed a pH of 5.8 and a lower ash content, indicating that this liquor was easy to be treated in the subsequent stage to recover the by-products and energy. The obtained lignin with high proportion of low molecular weight lignin was claimed to be applicable as an extender or as a feedstock for the synthesis of phenol-formaldehyde resins. The solvent and by-products recovery was simulated based on 1,000 kg/h of dry raw material and solvent input flow rate

7,0 kg/h with a liquid/solid ratio of 7 (Fig. 11.4). Lignin was precipitated by adjusting pH to 2 with acidified water, and ethylene glycol was recovered by multiple distillations. By simulation with commercial software (Aspen Plus), 91% of the ethylene glycol exiting in the digester was recovered, and 88% water was obtained and recycled. In a proposed recovering scheme, lignin and sugar recoveries accounted for 22% and 35% of the original lignin and sugar in the feedstock were achieved, respectively.