Deactivation behaviour of modified ZSM-5 zeolite catalysts to conversion of ethanol: mechanism, control and monitoring

通过推广生物乙醇作为碳源，特别是通过将其转化与高效的汽油精炼工艺相结合，预计化学工业的经济和生态改善。一个重要的步骤可能是通过应用木材发酵技术而不是糖等食品成分来独立于食用农作物。此外，这还可以使化工企业从化石油加工到利用可再生碳源的过渡更加顺利。乙醇的转化（所谓的ETH工艺）已经从实验的角度进行了数十年的研究和优化。然而，数学和分子建模的潜力尚未得到充分利用。不同的模型应用于H-ZSM-5催化剂可能会导致详细的了解的物理化学性质和反应路线的相互作用，这将使定制催化剂的合成成为可能。本项目旨在从科学和实验的角度对改性催化剂样品的失活，结焦和产物形成行为进行基本的了解。这将允许对催化剂和反应条件进行有针对性的修改，以改善长期稳定性和产物馏分选择性。作为下一步，向乙醇进料中加入水将作为催化剂在没有初步精馏的情况下转化生物乙醇的适用性的指示。最后，仅使用不同来源的机械预处理发酵液将显示生物乙醇和石油化学之间直接相互作用的经济和能量潜力。用乙烯和水的混合物进行的一些实验将完成对催化剂材料内部反应路线的理解。乙烯和水在该反应中起着关键作用，因为乙醇的脱水是反应机理中不可避免的第一步。通过使用固态和物理化学表征方法、微型植物试管反应器上的催化试验以及不同的数学和分子建模方法，确保对催化剂性能的深入了解。

Economical and ecological improvements within the chemical industry are expected from the promotion of bioethanol as carbon source; especially by combining its conversion with highly efficient petrol refining processes. An important step will probably be the independence from edible agricultural crop by application of technologies for fermentation of wood instead of food ingredients like sugar. Furthermore, this could smooth the transition for chemical companies from processing fossil oil to utilizing regenerative carbon sources.The conversion of ethanol (so-called ETH process) has been investigated and optimized from an experimental point of view for decades now. However, the potential of mathematical and molecular modelling is not fully exploited yet. The application of different models to H-ZSM-5 catalysts will probably lead to detailed insights into the interplay of physicochemical properties and reaction routes, which will render the synthesis of tailored catalysts possible.This project aims to achive a fundamental understanding of deactivation, coking and product formation behaviour of modified catalyst samples from a scientific and experimental viewpoint. This will allow for targeted modifications of the catalyst and reaction conditions to improve long-term stability and product fraction selectivity. As next step, addition of water to the ethanol feed will serve as indication of the catalyst's suitability in the conversion of bioethanol without preliminary rectification. Finally, usage of only mechanical pretreated fermentation broths of different origin will show the economic and energetic potential of a direct interaction between bioethanol and petrol chemistry.A few experiments with mixtures of ethene and water will complete the understanding of reactions routes inside the catalyst material. Ethene and water have a key role in this reaction because the dehydration of ethanol is the inevitable first step in the reaction mechanism.A solid understanding of the catalyst's properties is ensured by usage of solid-state as well as physicochemical characterization methods, catalytical tests on a microplant test-tube reactor as well as different methods of mathematical and molecular modelling.