![[BioMatNet Database - FAIR Program]](../images/Fair.gif) |
Commercial Success of ECLAIR Programme
AGRE-0044: Upgrading straw into pulp, paper and polymeric materials |
AGRE-0044: Upgrading straw into pulp, paper and polymeric materials
Science Background
Wheat straw is regarded by many as a waste product and as such is readily available in many EU Member States. It has been used in the past for papermaking, however, environmental and quality issues have generally prevented its use. As a fibre source, straw still has significant potential if suitable methods can be developed.
Objectives
This project investigated a novel pulping process, together with the equipment required to provide suitable chopped straw as feed, in order to produce unbleached straw pulp for use in packaging grade papers. The project also investigated the industrial use of straw for the manufacture of composite materials for which there is an increasing demand. In addition, it looked at the environmental impacts of straw processing by this new process and investigated effluent treatment. Overall, it aimed to provide the technical and economic information required in order to make a decision to build full-scale straw processing plants.
Significant changes and results since end of ECLAIR
Results from further research carried out by St Regis Paper Co, UK, were promising, however they could not justify the major investment required to carry out full-scale testing. In particular, there is a need for further research to demonstrate that effluent can be treated economically. The pulp properties from the Bivis (Clextral, France) extruder are good, although raw material preparation needs to be improved, particularly in relation to cutting and cleaning.
Results
At end of this ECLAIR project
Straw varieties that were most suitable for papermaking were identified. A straw preparation system was developed that consisted of a bale-breaking device, metering rake and rotary slicing device, and was shown to require less power, be quieter, produce less dust and have lower maintenance requirements than conventional chopping machines. Two pulping methods were investigated: Bivis twin screw extruder for an unbleached pulp (manufactured by Clextral, France) and STEX continuous steam explosion. As a result research focused on the former which gave high yields. Optimum operating conditions for the Bivis process were identified, resulting in a high yield of unbleached pulp. The properties of the pulps were improved as compared with pulps produced from waste paper currently used in the manufacture of fluting medium papers. The pulp was then treated after extruder pulping but before papermaking to optimize the stiffness characteristics. This step could be avoided if the shive was fractionated out. Several technologies for effluent treatment were investigated. Ultrafiltration in a pilot plant was operated for about 180 days without any major problem, however investment and operating cost were too high to justify this technique. Fungal treatments were designed that were comparable with those reported for fungal treatment of other pulp and paper effluents.
An industrial scale pilot plant pulping unit capable of producing between 2 and 3 tonnes of straw pulp per hour based on a Clextral KRO 200 Bivis extruder was designed, commissioned and built. Straw pulp from this pilot plant was used for a series of trials on industrial paper machines. Pulp from the STEX process was used to produce new polymeric materials. As a result of optimising spinning conditions, regenerated fibres with commercially sound properties were obtained from both bleached and unbleached straw pulps. Composites with strongly improved impact and strength properties were produced both from microbial and synthetic thermoplastics (PHB and polypropylene) reinforced with up to 50% STEX straw fibres. The materials from the industrial pilot scale plant were suitable for use as a substitute for glass fibre in the production of pipes. Interest in this work was shown by a number of companies in France and Italy.
Current position
St Regis Paper Co, UK, used a small percentage of straw to supplemented furnish (paper-making ingredients) in production of packaging grade paper. The product was of a favourable quality and was sold, but not marketed as containing straw. Extended trials continued in-house with increased straw percentages. However, the final in-house report concluded that although straw did not reduce the quality, neither did it enhance the quality of the product. The facilities at St Regis were to small to justify the major investment required to carry out full-scale testing, thus research was not continued. The pulp properties from the Bivis (Clextral, France) extruder are good, although raw material preparation needs to be improved, particularly in relation to cutting and cleaning. Clextral have not carried out further development or industrial application of the pilot plant developed in this project. However, the Bivis extruder has been used for processing pulps from wood chips, hemp, flax and other annuals, as well as bagasse.
Impact
Commercial
Although the quality of paper containing straw is not reduced, further research (particularly on effluent treatment) is needed before production of paper from straw is economic.
Associated
Some of the experience gained by St Regis Paper in this project has been transferred to two UK LINK projects coordinated at Silsoe Research Institute. Originally the Bivis technology was to be used in the LINK projects, however this did not occur due to St Regis Paper ending their straw-related research activities. The first project, Storage of fibrous crop material – FIBSTORE, developed techniques to prevent degradation of straw during storage by application of biocides. Limited evaluations of the suitability of various stored straw samples to industrial applications were achieved in that the biocide treatment was found to have no effect on particleboard quality. The second, Dry fractionation of cereal straw to separate botanical fractions – CROPFRACT, developed laboratory and industrial scale approaches to disconnecting and segregating dry botanical fractions of wheat straw. Pure leaf removal was achieved from sliced straw, but further roller milling to release leaf sheath was shown to be non-viable. As compared with whole straw, internode material was advantageous for board making and paper pulp production and leaf material had advantages for animal feed applications.
Further Information
Leathwood, M. (1997) Upgrading straw into pulp, paper and polymeric materials. In: Proceedings of the European Conference on Pulp and Paper Research: The present and the future (Eds: A. Arabatzis, L. Eriksson, I. Seone) pp171-176
Contacts
Author
Clextral
Silsoe Research Institute
St Regis Paper Company Lt
© Copyright 2006 Policy Statements
Updated
by CPL Press:
03/07/2007
- biomatnet@biomatnet.org
 |
 |
 |
News |
 |
Events |
|
|