Delignification

delignification

[dē‚lig·nə·fə′kā·shən]
(chemical engineering)
A chemical process for removing lignin from wood.

Delignification

 

destruction of the lignin that fills the intermycelial spaces in the walls of plant cells. Delignification occurs in a dead cell through the activity of enzymes secreted by neighboring living cells or parasitic fungi that cause, for example, white rot of woody plants. In the stalks of herbaceous plants, the process precedes obliteration and destruction of the internal elements of the protoxylem. Delignification and subsequent thinning of the sclereid walls accompany the maturation of pears and quinces. Delignification is used in industry to obtain cellulose; the lignin is removed from the cell walls by boiling wood at high pressure with caustic soda or calcium bisulfite. Delignification may also be caused by the action of Schultze powder (nitric acid with Berthollet salt) on the cell walls.

References in periodicals archive ?
mill has conducted a pilot-scale medium consistency oxygen delignification (MCOD) trial using a proprietary reactor as part of an integrated delignification system.
Also the oxygen delignification process will be upgraded and new wash presses installed.
Our current research effort can be divided into four areas: measurement and quantification of mixing in pulp fibre suspensions, improving gas-liquid-fibre contacting in oxygen delignification and bleaching stages, utilizing mixing and reactor design to optimize generation of pulping and bleaching chemicals, and developing criteria for repulper and disperser design based on the mechanical action imposed by the units.
Marutzky and Roffael (1977) discussed the conversions of [omega]-hydroxypropiovanillon into acetovanillon (retro-aldol reaction), [alpha]-(3-methoxy-4-hydroxyphenyl)-glycerin-[beta]-guaiacylether into 3-methoxy-4-hydroxy-styryl-[beta]-guaiacylether (retro-Prins reaction) as well as [beta]-1-dilignol-units toward styryl derivatives (retro-Prins reaction) as potential delignification reactions, which also lead to the formation of formaldehyde.
Hence most researchers have focused on surface treatment to the wood (dewaxing, delignification, bleaching, acetylation, and chemical grafting) and using various coupling agents to improve the wood and polymer interface.
Some of his accomplishments include implementing the first MC oxygen bleaching system, studying the organic and inorganic reactions of chlorine dioxide to advance ECF bleaching, and increasing pulp yield with oxygen delignification.
In addition, Metso Automation will deliver online analyzers, which will be included in the controls of the fiber line delignification and pulp brightness, and in the causticizing controls of the white liquor plant.
To remove the dark brown colour and increase brightness, the pulp is usually bleached in several delignification and extraction stages employing oxygen, chlorine dioxide, sodium hydroxide and hydrogen peroxide.
At Weyerhaeuser's Plymouth facility, the group was particularly interested in seeing and learning more about the mill's wood handling and preparation; pulping, oxygen delignification and bleaching systems; chemical recovery; the use of recycled materials to make containerboard; and the mill's effluent treatment system.
Metso Paper's delivery will include the modernization of the washing and screening systems, as well as of the oxygen delignification and bleaching processes.
92] produced sugar and ethanol from cellulosic resources like rice, straw, grass, bagasse, sawdust and newsprint, after chemical delignification with trichoderma cellulose.
Ozone bleaching and delignification is being used more for chemical pulps.