Semenenko N. Оxidative – organosolvent technologies of processed wheat straw stems

Cellulose production requires the use of a large number of chemicals, a significant duration of processes, is characterized by harmful emissions into the atmosphere and the formation of spent cooking solutions. Therefore, today it is important to create environmentally friendly pulp mills. The first section of the dissertation describes the current state of the pulp and paper industry. Features of anatomical, microscopic structure and chemical composition of plant raw materials are shown. Oxidative - solvent methods of delignification of vegetable raw materials with the use of peracids are described. The ways of application of oxidative - organosolvent straw cellulose and oxidative lignin in various industries are described. The choice of research direction is substantiated. The second section of the dissertation presents the chemical composition of wheat straw, which was used for research. Methods of cooking wheat straw stalks, determination of paper-forming properties of cellulose, production of packaging types of paper, research of composition of spent solutions and sorption capacity of oxidative lignin are given. Methods and devices for quality control of cellulose and cardboard and paper products, as well as methods of mathematical processing of research results are presented. The third section is devoted to the development of modes of producing straw cellulose by oxidative-organosolvent methods of delignification. The third section is devoted to the development of modes for obtaining straw cellulose by oxidative-organosolvent methods of delignification. Peroxoformic method (POF), cooking in the system acetic acid - water - hydrogen peroxide (AP) and cooking in the system acetic acid - water - hydrogen peroxide - alcohol (APA) were studied as methods of delignification of vegetable raw materials. Titanium oxide, sodium tungstate and sodium molybdate were used as catalysts for their intensification. According to the obtained experimental data, mathematical processing was performed to establish the optimal conditions of the delignification process. The morphological features of the obtained oxidative - organosolvent straw cellulose were established by the method of scanning electron microscopy. From the lignin - carbohydrate diagram it is established that by increasing the efficiency of lignin removal from wheat straw, the studied methods are located in the following row: POF - AP - APA. The analysis of the washing waters formed after APA of cooking of stalks of wheat straw is carried out. It is established that according to quality indicators they can be reused for technological needs. The fourth section is devoted to the study of the use of waste solutions. Showed the possibility of using 10% of spent lye in the composition of fresh cooking solution without significant deterioration of the quality of straw pulp. A scheme for regeneration of cooking solution components after delignification of wheat straw in the system "acetic acid - water - hydrogen peroxide - ethyl alcohol" is proposed, which provides for their use in a closed cycle, which significantly reduces the consumption of chemical reagents and industrial waste. The fifth section examines the paper-forming properties of the obtained cellulose in the composition of packaging types of paper: wrapping paper, paper for packaging food on vending machines, paper - bases for parchment. The general basic technological scheme of the process of obtaining straw cellulose in the system "acetic acid - water - hydrogen peroxide - ethyl alcohol" is given. Feasibility study of the practical implementation of the results obtained from the introduction of OPS method of obtaining straw pulp. It is shown that the payback period does not exceed the normative indicators for the industry and is 6.4 years, the expected economic effect from the introduction of the proposed method of delignification of vegetable raw materials is about 76.016 million UAH.