Oxygen delignification operations

Charles, N., Mansfield, S. D., Mirochnik, O., and Duff, S. J.B., 2003, Effect of oxygen delignification operating parameters on downstream enzymatic hydrolysis of softwood substrates, Biotechnol. Progr. 19 1606-1611. 

Figure 20-1 Simplified overview of a typical kraft process showing chemical pulping, oxygen delignification, pulp bleaching, and chemical recovery systems. Important mixing operations are indicated by the NAMF mixing icon.

Coniferous lignin contains 2% benzyl groups of the phenolic type and 6% of the alkanoic type (see Fig. 10). About 0.24 oxygen atoms in lignin are present as benzyl alcohols or benzyl aryl ethers. These groups are involved in the delignification reactions in chemical pulping operations. 

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