June 29, 1999
Tohoku Paper's Akita Mill to Produce ECF Pulp
Nippon Paper Industries Co., Ltd.
The Akita Mill (*1) of Tohoku Paper Co., Ltd., a subsidiary of Nippon Paper Industries Co., Ltd. (NPI), has announced its decision to produce ECF pulp with a bleaching process that does not use chlorine.
Kraft pulp (KP) is made by cooking wood chips in caustic soda to extract wood fiber, which is then bleached using chemicals, such as chlorine, chlorine dioxide, sodium hypochlorite, and oxygen. In recent years, pulp makers in the West have begun to use a new bleaching process known as the ECF (elementally chlorine free) method, which does not make use of Cl2.
The elemental chlorine currently used for first-stage bleaching in the Akita Mill's hardwood KP line, which has 650 ton daily capacity, will be replaced with chlorine dioxide. To do this, the plant will also have to upgrade its chlorine dioxide generating capacity. The switch to chlorine dioxide is expected to lower AOX readings by about half to 0.4-0.5 per ton of pulp. (*2) The AOX (adsorbable organic halides) reading is an indicator of dioxin discharge levels.
NPI already has ECF pulping lines in operation at its Kushiro Mill (363 tons of softwood pulp per day) and at its Asahikawa Mill (100 tons of softwood pulp per day). The Akita Mill will thus be the third ECF pulp operation for NPI, and the fourth in Japan as a whole. In the future we shall also switch to the ECF bleaching process at our all other mills, and we also plan to eventually phase out the use of chlorine compound bleaching completely at some mills.
The following are a few key facts concerning the project.
1) Upgraded capacity for our ClO2 plant: 4.5 -> 6t/day
2) Reconstruction of bleaching tower
Construction starts in October 1999, finishes in April 2000.
(*1) Tohoku Paper Co., Ltd.
Wholly owned subsidiary of NPI. Annual capacity: 140,000 tons of paper and 300,000 tons of paperboard (final figures for 1998). The company's entire output of paper is purchased and marketed by NPI.
(*2) Chlorine and dioxins
The use of large amounts of gaseous chlorine for bleaching may generate dioxins. For this reason, the Japan Paper Association has voluntarily decided to limit its AOX emissions (a measure of dioxin emissions) to less than 1.5 kg per ton of pulp. It is believed that dioxins are not produced when AOX emissions are held to this level. While all NPI facilities are already under this limit, the switch to ECF bleaching will further lower our AOX emissions.