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Fördröja åldrandet av elektrotekniskt papper genom kemikalietillsats: En studie av dicyandiamids påverkan
Karlstad University, Faculty of Technology and Science.
2011 (Swedish)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesisAlternative title
Delay the Ageing of Electro Technical Paper by Addition of Chemicals : A Study of the Effect of Dicyandiamide (English)
Abstract [sv]

Nordic Paper Åmotfors tillverkar elektrotekniskt papper som används till att isolera lindningarna i transformatorer. Det är viktigt att bibehålla papprets egenskaper under en mycket lång tid då en transformators livlängd är lång. Syftet med detta examensarbete var att undersöka huruvida tillsats av en kemikalie bestående av dicyandiamid kan fördröja åldrandet av de papper som Nordic Paper tillverkar. Förhoppningen var att deras papper därefter skulle klara de krav-parametrar som finns för papper som åldrats i olja. Kemikalien som användes var Cartafix® WE liquid.

Försök utfördes där olika kemikaliedoseringar tillsattes i mälden. Pappersark tillverkades och kvävehalten mättes därefter för att verifiera att kemikalien fastnat i de färdiga papprena. Pappers-arken åldrades sedan endera i olja eller i luft, och den kvarvarande polymerisationsgraden (DP) mättes. Sprängstyrke- och konduktivitetstester utfördes också. Papper som Nordic Paper tillverkat beströks med olika kemikaliedoseringar och samma tester utfördes även på dessa.

Resultaten visade att retentionen av kemikalien var låg. Kvävehalten blev inte högre än 1 % och detta skedde vid 10-20 % kemikalietillsats.

Efter åldring i olja minskade DP relativt mycket, vilket medförde att papprena inte uppnådde de uppsatta kraven (maximalt 50 % minskning). Tillsats av kemikalien förbättrade dock papprets åldringsegenskaper med nästan 45 % om icke-modifierat papper jämförs med det modifierade pappret som hade högst DP (10 % kemikalietillsats, vilket motsvarade 1 % kvävehalt).

Papper som modifierats med kemikalietillsats i mälden gav lägre DP då åldringen skett i luft jämfört med icke-modifierat papper. DP minskade avsevärt efter åldring för papper som bestrukits med kemikalien.

Kemikalietillsats försämrade både sprängstyrkan och konduktivteten.

Abstract [en]

Nordic Paper Åmotfors manufactures electro technical paper that is used to isolate the windings in transformers. It is important to maintain the properties of the paper during a long period of time because the life of a transformer is extensive. The purpose of this thesis was to investigate whether or not addition by a chemical consisting of dicyandiamide could delay the ageing of the papers that Nordic Paper manufactures. The aspiration was that their paper would then fulfil the requirements that are applicable to papers that have been aged in oil. The chemical that was utilised is called Cartafix® WE liquid.

Experiments were conducted where different dosages of the chemical were added to the stock. Sheets of paper were manufactured and the nitrogen level was then measured in order to verify that the chemical had been fused in the finished paper. The paper sheets were then aged in either oil or air and the remaining degree of polymerisation was measured. Bursting strength and conductivity were also evaluated. Papers that Nordic Paper had manufactured were coated with different dosages of the chemical and then investigated in the same manner.

The results showed that the retention of the chemical was relatively low. The nitrogen level did not exceed 1 %, which occurred at 10-20 % addition of the chemical.

After ageing in oil, the degree of polymerisation was significantly reduced, which meant that the papers did not fulfil the requirement of a maximum of 50 % reduction. The addition of the chemical did however improve the ageing resistance with nearly 45 % if the unmodified paper is compared to the modified paper with the highest degree of polymerisation (10 % addition, equivalent to 1 % nitrogen).

Papers that had been modified by addition of chemicals in the stock and had been aged in air exhibited lower degree of polymerisation than unmodified paper. The degree of polymerisation was significantly reduced for papers that had been coated and aged in air.

Addition of chemicals resulted in both lower bursting strength and lower conductivity.

Place, publisher, year, edition, pages
2011. , 42 p.
Keyword [en]
electro technical paper, transformer paper, ageing of paper, delay ageing of paper, addition of chemicals
Keyword [sv]
elektrotekniskt papper, transformatorpapper, åldrande av papper, fördröja åldrande av papper, kemikalietillsats
National Category
Paper, Pulp and Fiber Technology
Identifiers
URN: urn:nbn:se:kau:diva-7357OAI: oai:DiVA.org:kau-7357DiVA: diva2:414547
Uppsok
Technology
Supervisors
Examiners
Available from: 2011-05-12 Created: 2011-05-03 Last updated: 2011-05-12Bibliographically approved

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