Topic A.5: Pre-utilization of wood and other renewable resources through the extraction of chemical raw materials

To develop new fields of application of by-products and to increase cascade utilization’s entire added value, certain constituents are chemically extracted in the first stage of a multi-stage process. The emphasis is on specific extractions and polyoses resolved from the cell structures. Our knowledge of the interaction between types and composition of polyoses and extractives of various renewable resources (wood, wheat, fiber crop) and various extraction methods is insufficient (Blumentritt, 2010). Consequently, various utilization possibilities should be developed for renewable resources, which can then be applied in a multi-stage utilization cascade. Suitable raw materials, such as types of wood, fiber crop, and grass types, are then selected for this purpose. The chemical constituents can be accurately characterized before the extraction, (see topics A.2, A.3 and A.4).

The aim of this topic is the optimized utilization of valuable wood materials, with the remaining wood used as raw material with modified properties. The selection of products should be such that the optimum added value is obtained. Various methods are applied to produce extractives and polyoses: (1) oxidative, (2) hot water extraction, (3) acid hydrolysis, and (4) solution extraction. The cellulose is hardly affected and through the pre-utilization of possible modification steps, becomes even more extractable. Finally, depending on the used extraction method, the composition of the extracted polyoses and/or other extractive materials can be depicted as process model. By employing statistical test models, the extraction procedures can be technically optimized. By using energy balances (see topic A.7), an economic assessment of the entire process becomes possible. Basic knowledge is thus created of the cascade utilization of renewable resources regarding process control and the possibilities of technical process optimization are demonstrated. The extracted raw materials are primarily the starting point for bioethanol extraction and are therefore also related to the topics A.7 and B.6.