FAIR-CT97-3855 Comparative production of dissolving pulps by acetosolv, formacell, milox and steaming-extraction pulping

Contacts
Further Information



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FAIR Area 1.3 - Forestry-Wood Chain : Paper/Pulp : Pulping : Wood (Lignocellulose)

	Type of Project	Shared Cost
	Contract No	FAIR-CT97-3855
	Total Cost	1 270 000 ECU
	EC Contribution	819,500 ECU
	Start Date	01/07/1998
	Duration	24 months

Comparative production of dissolving pulps by acetosolv, formacell, milox and steaming-extraction pulping

Objectives

Due to environmental problems in traditional pulping processes, several new pulping concepts have been developed in Europe in the last decade. At that time the main focus was on the production of new paper pulp. However, in contrast to KRAFT pulping, the acidic processes Acetosolv, Formacell and Milox offer the advantage that they include the hydrolysis of hemicelluloses and produce dissolving pulps as a feedstock for cellulose derivatives and cellulosic fibres. This is, at least partly, also true for steaming-extraction. Based on autohydrolysis of intra- and intermolecular bonds, this process renders hemicelluloses and lignin extractable with water and alkali and has the potential to deliver a highly accessible pulp.

Technical Approach

All processes under consideration can be run as mini-plants and produce specific pulp grade for special applications, typical in processing of dissolving pulps. The impact of pulping and bleaching parameters on the physical and chemical characteristics of pulp will be investigated and directly compared to sulphite dissolving pulps from an industrial partner. Selected pulps will be used for the production of cellulose acetate and viscose fibres. In addition N-methylmorpholine-oxide as direct solvent for cellulose (NMMO process) will be used for the formation of regenerated cellulosic fibres and blown cellulosic films. This comparison has a potential in offering a completely new process chain from wood to polymeric products. Acetosolv, Formacell, Milox, and steaming-extraction pulps will be produced from industrial beech, eucalyptus and aspen wood chips. Starting from published pulping conditions, the processes will be adapted to the production of high purity pulps. In addition the traditional acid sulphite process will be investigated as a reference. By using the same starting material the performance of the different processes can be compared. For each of the processes different bleaching concepts have been developed. Rhese sequences will be adapted to different pulps allowing a judgement on the impacts of different bleaching agents, as well as on the influence of alkaline extractions. Physical characterisation of fibres and films will include not only mechanical testing, but also structural characterisation by x-ray analysis and electron microscopy. Most of the work will deal with laboratory scale experiments on the behaviour of the different bleached pulps in the viscose and the NMMO process. Viscose and cellulose acetate manufacturing by experienced industrial partners both for the new and reference sulfite pulps will lead to an improved understanding of pulp performance and reactivity.

The Lenzing AG integrated factory for production of
dissolving pulp and viscose fibres, Lenzing, Austria

Contacts

Coordinator

• Federal Research Centre for Forestry & Forest Products / GERMANY

EC Scientific Officer

• Ignacio SEOANE / European Commission DG Research Theme 1 Key Action 5.3 / BELGIUM

Participant

• Hans-Peter FINK / Fraunhofer-Gesellschaft Fraunhofer-Institute for Applied Polymer Research / GERMANY
• H. SIXTA / Lenzing AG AUSTRIA
• H. AL GHATTA / Sinco Engineering S.P.A. ITALY