Pulp and Paper

Process overview

During the paper/pulp manufacturing process, HISAKA heat exchangers are used to save energy and resources, such as heating/cooling fluids that contain solid materials, which are derived from wood chips, and for heat exchange to recover the chemicals that were used or will be used to extract pulp from raw wood.

Digestion Process

Digestion process is the process where wooden chips are heated and dissolved in chemicals in order to extract pulps. Which will later on serve as the raw material in paper production. HISAKA heat exchangers, which have good heat exchange efficiency, used in white liquor heaters.
(White liquor: a solution containing sodium hydroxide and sodium sulphide)

Chemical Solution Recovery Process

The condensed black liquor in a boiler will generate steam that can be further use to either generate electricity or to serve as a heat source for paper drying HISAKA heat exchangers are used as a preheaters for dilute black liquor.
(Black liquor: waste liquid from which lignin has been dissolved)

Bleaching Process

Bleaching process mainly serves to remove and bleach any coloring components from the lignin-containing (unbleached) pulps in the digester. Chlorine dioxide used for bleaching is a strong acid solutions. Therefore, titanium plates, which are highly resistant to corrosion, are used.
(Lignin: component that bonds wood fibers together)

Paper Making Process

The digested and bleached pulps are then fed to a paper machine used as raw materials for paper production. HISAKA heat exchangers are used to cool white water that contain fibers, and as oil coolers for rolls.