Objectif The project aims to demonstrate a novel pre-treatment debarking system for eucalyptus globulus trees at a kraft pulp mill. The system enables the collection of bark for use as fuel in a water tube boiler. The energy substitution is estimated at 12 650 TOE/yr while a payback time of two years is foreseen.The average debarking efficiency obtained is below the objective value : 83. 6 % on average instead of 90 %, with a large variation from 53. 4 % to 98. 1 %. The higher efficiency values are reached when processing a high proportion of recently cut wood (up to 15 days). When processing dry wood, with a felling age between 1 and 3 months, the debarking efficiency will be 60 % approx.However, the average efficiency values achieved lead to the conclusion that significant progress has been made in the eucalyptus globulus debarking process. Besides, the pretreatment unit has already been replicated in other Portuguese eucalyptus paper mills.The gross energy savings are lower than forecast : 8128 toe/y instead of 12. 650 toe/y. The main reasons for this are the following :- lower debarking efficiency than foreseen;- some difficulties in operating the debarking line so that the percentage of undebarked wood in the pretreatment line was limited to 30 % instead of 50 %;- bark moisturegreater than predicted, 50 % instead of 30 %, notably due to water utilization along the pretreatment line which improves the logs flow.The payback time for the project rises accordingly from 2 years as initially foreseen to 4. 3 years.Eucalyptus is used at a number of pulp mills in Portugal and Spain. However, there are no successfully operating high efficiency debarking technologies currently in operation, particularly for wood which has been stored for 1 to 8 months. At present bark is stripped manually in the forest and the bark is not utilised.The pre-treatment debarking unit being demonstrated consists of a number of toothed rotors which move at high speed constantly adjusting to the wood diameter, thereby reducing bark adhesion and breaking the bark's fibre structure. Further modifications have been necessary to accommodate the handling of unbarked eucalyptus at the pulping plant, including changes to the feeding tables and conveyors, and the addition of bark handling equipment.The pre-treatment device is placed on the infeed conveyor in order to facilitate the succeeding friction debarking and thereby achieving an overall debarking efficiency of 90%.The debarking equipment produces 142 kg bark/tonne pulp at 30% moisture content.The bark will be burnt with conventional fuel in a multi-fuel water type boiler resulting in a saving of 40 kg of oil/tonne of pulp produced, producing100 t/hr steam. The annual saving is approx 12 650 tonnes of oil per year. The preliminary debarking system has other benefits beside the direct energy saving,these include forest labour cost reduction, the potential marketing of the bark to other users, and the elimination/reduction of wood storage problems. Programme(s) ENG-ENDEMO C - Programme (EEC) of demonstration projects and industrial pilot projects (EEC) in the energy field, 1985-1989 Thème(s) 1.8 - BIOMASS HARVESTING Appel à propositions Data not available Régime de financement DEM - Demonstration contracts Coordinateur SOPORCEL Contribution de l’UE Aucune donnée Adresse PO - 3081 FIGUEIRA DA FOZ CODEX Portugal Voir sur la carte Coût total Aucune donnée
