纸浆氧脱木素过程中草酸根形成机制及其控制的研究

Oxygen delignification is the main technology in the pulp clean bleaching processes, which laid a foundation for effluent zero discharge in bleach plant. With the enhancement of environmental awareness, effluent of oxygen delignification is introduced to wash cooked pulp in a lot of pulp mills. However, higher degree of system closure easily causes the accumulation of oxalic acid, which increases the risk of oxalate scaling. Consquently, the question of oxalate scaling is becoming urgent in pulp and paper industry as it has a bad influence on the energy saving and clean production directly. In the project, the key of the oxalate scaling control problems - the formation mechanism and control of oxalate during oxygen delignification of pulp will be studied. By means of new method of oxalate determination, the source and formation mechanism of oxalate will be revealed. Also the mathematical prediction model will be developed. It's anticipated that the formation of oxalate during oxygen delignification could be reflected from the results above. Furthermore, the enzymatic method will be utilized for controlling oxalate formation during oxygen delignification. This research will provide theoretical basis and technical support for the effective control of oxalate scaling during pulp and papermaking process. All the research results will be of significance for promoting cleaner production, accelerating the development of low-carbon economy.

氧脱木素是目前纸浆清洁漂白的主体工艺，它为实现漂白车间无废水排放奠定了基础。随着环保意识的增强，大多数浆厂开始将氧脱木素废液回用于蒸煮工段洗涤纸浆。然而，氧脱木素废液的回用激化了草酸根离子富集，致使草酸盐结垢随之加剧。由于直接关系到节能减排和清洁生产，草酸盐结垢已成为制浆造纸工业中亟待解决的难题之一。本课题针对如何有效控制制浆造纸过程中草酸盐结垢这一技术难题，提出对纸浆氧脱木素过程中草酸根形成机制及其控制的研究。利用新建立的草酸根测定方法，系统研究纸浆氧脱木素过程中草酸根的来源和形成过程，揭示纸浆氧脱木素过程中草酸根的形成机制，建立草酸根形成的数学预测模型；开辟生物酶法控制纸浆氧脱木素过程中草酸根形成的新途径，并明确其控制机理，为制浆造纸过程中草酸盐结垢的控制提供理论依据和技术支持。本研究成果对推进我国制浆造纸工业清洁生产、加快发展低碳经济具有长远意义。

氧脱木素是普遍采用的最基本的无污染纸浆漂白方式，是目前纸浆清洁漂白的主体工艺。草酸根是纸浆氧脱木素废液的组分之一，它能够与多种金属离子结合生成难溶的草酸盐，从而导致一系列设备结垢问题的产生。草酸盐结垢是现代制浆造纸工业中亟待解决的难题之一。本项目针对这一难题，以硫酸盐浆为研究对象，利用新建立的草酸根测定方法，深入研究了纸浆氧脱木素过程中草酸根的形成规律及其影响因素，揭示了氧脱木素过程中草酸根的形成机制，建立了草酸根形成的数学预测模型；开辟了生物酶法控制氧脱木素过程中草酸根形成的新途径；采用动态监测技术结合现代分析手段，揭示了氧脱木素废液循环利用和处理过程中草酸根的行为及其草酸盐结垢的形成过程，为有效减少和控制后续生产和废液处理过程中草酸盐结垢的形成提供理论依据和技术支持。在项目研究过程中，已发表学术论文17篇（其中，SCI收录论文10篇），申请发明专利8项，已获授权专利1项。