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국내산 소나무의 APMP 기술 최적화 연구 원문보기

  • 저자

    임수진

  • 학위수여기관

    경상대학교 대학원

  • 학위구분

    국내석사

  • 학과

    임산공학과 목재화학및펄프·제지공학전공

  • 지도교수

  • 발행년도

    2014

  • 총페이지

    ⅷ, 41 p.

  • 키워드

    APMP 기계펄프 과산화수소표백;

  • 언어

    kor

  • 원문 URL

    http://www.riss.kr/link?id=T13534250&outLink=K  

  • 초록

    Thermomechanical pulp(TMP) is pulp produced by defibratiing wood chips using heat. If steam-treated wood chips are just ground up with the refiner plates, they are easily separated into individual fibers. The pulp is then screened and cleaned, any clump of fibers are reprocessed. This process gives a high yield of fibers from the wood (around 95 per cent) and as the lignin has not removed, the pulp fibers are not stable and rigid. However, the biggest drawback of TMP processes is high energy consumption off the total energy consumption, normally only 200-300 kWh/t is used for pumping, screening, etc., which means that 90% of the total energy used in the production of TMP are used for defiberizing and refining. To reduce power consumption during refining, a gentle chemical treatment stage is adopted in order to defiber wood chips and develop necessary paper or board properties of the reulsting pulp. This pulping method is called chemi-thermomechanical pulp (CTMP) with yields in the range of 80 to 95 percent. CTMP, in principle, can be produced by various combinations of chemical treatments and mechanical defibration. In practical operation, sodium sulfite is the dominating chemical in softwood pulping, and alkaline hydrogen peroxide (APMP) is used in some special processes. Alkaline peroxide mechanical pulping has become a fast-growing alternative to sulfite chemicals in production of bleached chemi-mechanical pulp. Similar to sulfonation, carboxylation results in lignin with carboxylate groups which are capable of participating in hydrogen bonding, which increase fiber bonding in papermaking. Alkaline peroxide treatment of wood chips softens the lignin, resulting in easier fiber separation and less fines generation during refining. The typical discoloration of the pulp by the alkaline treatment, as found in the "cold soda" process, is avoided by adding the peroxide to the caustic solution. Added benefit of the process is that alkaline peroxide in the refiners can potentially eliminate the need for separate post bleaching. Currently, mechanical pulp produced in Korea, has been using the domestic pine, Pinus densiflora, as a raw material. Unfortunately, the pine contains a high amount of resins, which leads to trouble in runnability and defects in paper products. For the pre-treatment of wood chip, sodium hydroxide and hydrogen peroxide were added 3%, 5% and 7% based on OD chip weight, and the impregnation time of wood chips was 90 min and 120 min respectively. The increase in alkaline inputs resulted in improvement in strength and density in APMP process. At the same time, freeness and refining energy were reduced together. However, brightness of the pulp by bleaching, depended on the amount of hydrogen peroxide that was introduced into the impregnation stage. The softening extent of wood chips depended on the alkali dosage of in the APMP production process, but bleaching efficiency depended on the amount of peroxide. Therefore, the input ratio between the two chemicals were greatly important in improving bleaching efficiency. In this study, when the pine chips with lots of resin were used in APMP process, impregnation time significantly influenced pulp quality. Furthermore, by adjusting the mixing ratios between hydrogen peroxide and sodium hydroxide, bleaching efficiency, softening of wood chips and energy savings could positively be modified. As a result, the defibration efficiency of chip correlated with amount of the sodium hydroxide. Brightness was increased proportionally with amount of the hydrogen peroxide. But, the results were not much different from the soaking duration. Surprisingly, the flocculation size of pitch was tended to be increased as much as the increase of the soaking duration, but not the adding of chemicals. In conclusions, we explored the fresh methods to save energy required to refine as well as to reduce pitch trouble when using the domestic pine. To save the refining energy occupying most of the production cost of mechanical pulp, we could find that APMP process adopted was significantly beneficial before refining.


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