Oxidative coupling of methane
The direct oxidative coupling of methane (OCM) to C2-hydrocarbons is a reaction of major interest, as it could greatly enhance the sustainability of the petrochemical feedstock for energy and matter conversion. A joint effort to understand the mechanistic details of the process, and to design and synthesize tailored catalysts is essential for developing an industrial catalytic process for the OCM reaction.
A profound understanding of OCM requires a description of chemical and physical processes over a wide range of space and time dimensions:
- the identification of elementary steps and catalytic cycles through theoretical and experimental studies on model systems,
- the coupling of these molecular processes with transport of energy and molecules in meso- and macroscopic dimensions, and
- the chemical transformation of catalyst precursors into active phases, during which deactivation by compound formation, poisoning and reactant-induced restructuring may occur.
To master this challenge, an approach is required that combines concepts and methodologies of chemical synthesis, physical chemistry and surface science with chemical engineering. In a multi-disciplinary research approach we are addressing all relevant scales of length and time for both heterogeneous (surface) and homogeneous (gas phase) reactions involved in the OCM process.
- The studies will range from the “molecular world” using advanced catalytic model systems with a designed morphology to the “macroscopic world” by the development of the best suitable reactors for OCM, utilizing benchmark systems with regard to performance and stability under technologically relevant conditions (see Figure above).
Particularly promising systems will be thoroughly studied and optimized both with respect to the nature and stability of active sites and to scalable synthesis and transport properties of the formulated system. Candidates for new stable catalysts will be identified by screening methods on the basis of new test facilities.
On the catalyst side, extensive testing in various laboratory reactors and in the mini-plant will be performed with special emphasis on establishing a parameter profile of steady state performance for a macrokinetic model. These investigations will be guided by simulation studies on lab scale reactors and the mini-plant, also including the coupling with add-on processes for the conversion of methane and CO2 to syngas (see D 2-1).
The results obtained with up-scaled catalysts under realistic operation conditions will provide a feedback to the synthesis group to arrive finally at truly stable and functional catalysts.