Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/3898
Título: Estudo da estrutura de custos da produção de pasta e optimização da componente madeira. Inventariação e quantificação de perdas processuais de madeira no fabrico de pasta para papel
Autor: Burnay, Maria da Graça Temudo de Castro
Orientador: Pereira, Helena Margarida Nunes
Palavras-chave: Eucalyptus globulus
chips
pulp
procedural losses
Kraft process
Data de Defesa: 2011
Editora: ISA/UTL
Citação: Burnay, Maria da Graça Temudo de Castro - Estudo da estrutura de custos da produção de pasta e optimização da componente madeira. Inventariação e quantificação de perdas processuais de madeira no fabrico de pasta para papel. Lisboa: ISA, 2011
Resumo: In industrial activities, the performance and the producibility of the final product manufactured, depends on interstices and extrinsic factors of the industrial production cycle. In order to optimize the production cycle, first should be analyze and account the based resource of the transformation procedure, which is the raw material base that leads the market made in each industry. The availability and supply of raw materials for initial conversion, largely defines the productive capacity of an industrial cycle, along with the monitoring technology defendant, as well the precision manufacturing methods and specialized equipment to determine quality and yield of the final product. In this context the production of pulp for paper is a part of industrial sector, also with extremely important analytical parameters in all the circuit of manufacturing. The following work is an analysis of consumption capacity and conversion, of raw material based on pulp and paper industry, this is the wood of Eucalyptus globulus, as one of the best chosen species for paper manufacture. The efficiency of the industrial cycle, necessarily begins with the constant supply and receiving of the primary product processing, timber, this is where is determined the daily production capacity and the turn in profitability of the final product, pulp. The analysis of the profitability of eucalyptus wood at an industrial level, was determined by quantification and inventory of the main percentage losses in the processing of roundwood in pulp, in peeling, chipping and Kraft processes in a factory of Portucel Soporcel in Setubal. For the same purpose, were analyzed each transformation process manufacturing employment, in order to delineate how and where does the losses procedural associated belong, as well as the mechanism of the receiving system and supply of wood in roundwood with bark Eucalyptus globulus, as the initial and primary flow of processing industries. The definition of the main objectives of producibility and profitability of the industrial cycle plants, to meet the needs and demands of the trading market, depend on the ability to supply the raw material for converting the initial factory. In this way, is necessary to maintain an influent receiving wood and precise quantification of the industrial entry. Quantification methods of reception and production of a product, which may be more stringent, in industrial scale are constantly monitored and evaluated in order to detect the limitations and inaccuracies that can be improved or even eliminated if interfere in the accuracy of measurement daily production capacity of manufacturing. So throughout the study in question, were determined the error margins associated in each method of quantification of reception, as well in the determination of losses and production of pulp from Eucalyptus globulus wood, prepared in different ways throughout the process analysis. The margin of error was determined calculating the average error of each measurement made, using records of system measurement and quantification defendant, using the m3 standard as the volume unit of the process of industrial measurement adopted.Using the theory of propagation of errors in all weights and samples made in the inventory of the main and side timber flows, was associated a error of 2.76% for a cubic meter of wood in the quantification by the method of immersion in water, ± 20kg the margin of error of reading made in weighing the side streams and ±0.001kg in weighing samples. The main procedural losses of wood were identified on the flow of processed bark peeling, mechanic performed by a rotating drum. For greater accuracy, were analyzed the two-line debarking industrial, by selecting identical time bases of four hours on average, and collecting four samples with about 5kg of bark along the processing, at the end, on average there were about 5% losses in wood taken from the bark peeling in each line. Carried out on different days receptionist wood, on each line analyzed in duplicate, was noted that in days of heavy rainfall and especially in finer flows of roundwood, losses in mechanical processing chips were the most highlighted, revealing the section shelling the area, the greatest percentage loss of timber industry. With about 1% on average in each line peel, chips of shattered dimensions too thin for processing pulp, represent the second procedural losses in mechanical processing of roundwood into chips to Kraft cooking. The resulting wood of procedural losses in the plant in question, are use as biomass, converted into green energy that is self consumption and sold by the industrial core analyzed. Once converted into chips for paper pulp production, wood is directed to cooking, screening and bleaching through the process of Kraft delignification. Lignin removed through the black liquor, is recycled for conversion of biomass and green energy, while the liquor is bleach to white liquor, in recovered for reuse in other pulping processes. In the Kraft process is defined a yield of 52% of wood for Kraft pulp production, the main losses of processed wood are revealed in the content of knots and uncooked shives, riddled sequentially and removed from the production system, due the unfit features for industrial purpose. The knots and uncooked shives were determined by inventory and final weights, on the end of the industrial cycle production of pulp in similar conditions and temporal basis. Being carried out six tests and sampling weights, we can conclude that the knots and uncooked shives represent about 1,5 % of the wood processed in Kraft pulp. In the end, it was concluded on average, about 6% wood losses along the industrial processing of roundwood Eucalyptus globulus into chips for paper pulp production and 1,5% in pulping, mainly represented by the wood-drag carried by the bark, then the knots and uncooked shives content riddled and finally the chips due the size too thin called “sawdust”.
Descrição: Mestrado em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia
URI: http://hdl.handle.net/10400.5/3898
Aparece nas colecções:BISA - Dissertações de Mestrado / Master Thesis

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