CTMP Pulping principle


CTMP Pulping principle

Wood chips are impregnated with selected chemicals at a certain temperature to soften and swell the amorphous areas of lignin, hemicellulose and cellulose in wood.

When the temperature reaches the“glassy”conversion point of lignin , the fibers are separated from the wood matrix by the compression pulse action of the fluted disc and other mechanical actions during the disc grinding, and the fibers primary wall is torn apart to varying degrees, so that it can not only maintain the basic length of the fibre foundation, but also increase its specific surface area and form a considerable bonding force.

There is no substantial difference between chemical mechanical pulping and semi chemical pulping. Both require chemical treatment of wood chips and then mechanical pulping.

The chemical treatment of semi chemical pulp is deep, and the pulp yield is between 65% - 85%; And the chemical mechanical pulp is relatively shallow, the yield is relatively high, ranging from 85% -95%.

The purpose of chemical treatment of chemical pulp is to remove lignin as soon as possible; And the chemical mechanical pulp is to change the properties of lignin on the basis of keeping lignin as much as possible, so that the fiber after pulping can obtain better performance than that of mechanical pulp.

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