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MEthane activation via integrated MEmbrane REactors

Periodic Reporting for period 3 - MEMERE (MEthane activation via integrated MEmbrane REactors)

Reporting period: 2018-10-01 to 2020-01-31

One of the most interesting building blocks that can be produced from methane is ethylene, a very important base component for the chemical industry with a production of up to 200 million tons/year (forecast 2020). Current industrial production of ethylene, usually by steam cracking of expensive naphtha, is very energy intensive. It is the most energy consuming process of the chemical industry corresponding with 30% of the total energy consumption of the chemical industry.
An efficient way to produce C2 from methane is the direct route, consisting of the direct partial oxidation of methane with defect of oxygen to C2 (and water), referred to as oxidative coupling of methane (OCM). To make this reaction economically feasible, high C2 yields (>30%) are required, which are not yet achieved in experimental studies.
The key objective of the MEMERE project is the design, scale-up and validation of a novel membrane reactor for the direct conversion of methane into ethylene with integrated air separation. The focus of the project has been on the air separation through novel MIEC membranes integrated within a reactor operated at high temperature for OCM.
This allows the integration of different process steps in a single multifunctional unit. The project promises to solve for the first time the technical and process limits which makes the production of ethylene from methane currently not economical, thus opening new horizons for the production of C2 at higher yields and lower costs, at the same time reducing energy intensity (-50%), emissions (- 60%) and increased flexibility compared to the current state of the art technologies. This allows for a radical leap forward in the competitiveness of the EU process industry at global level, with particular focus on the strategic petrochemical sector, rejuvenating its role and re-establishing its leadership at global level, in line with the SPIRE objectives.
The work performed in MEMERE was divided in 9 work packages. the work can be summarized as

WP1 Management
WP1 is the work package on coordination and was divided in 3 tasks.

WP2 Catalyst Development
The objective of the WP2 wasto develop, test and characterise an OCM catalyst suitable for the operating conditions dictated by the use of a membrane reactor. The catalyst shouldbe active, selective and stable at high temperatures and under low oxygen partial pressures. We developed and tested different formulations based on amorphous silica, sol-gel or microporous silica. VITO developed and up-scaled their printing technology using JM and TUB catalysts and are now able to print quickly 40 mm diameter structured cylinders. These materials have been tested on TUB’s purpose build large-scale glass reactor. FINDEN has provided great insight in the different species in catalysts prepared by different routes. TUE has worked on the kinetics of JM’s Mn based OCM catalyst.

WP3 Membrane Development
The objectives of the WP3 for were the following:
• Mechanical properties assessment of the porous MgO tubes
• Sealing of the porous MgO tubes and their delivery for being integrated in the OCM reactor prototype
• Cost analysis of supports and membranes (including sealing)
In parallel TUE has been working on oxygen selective membrane preparation. TUE has developed single, dual ad tri-phase oxygen selective membranes.

WP4 Lab scale reactor
The aim of this WP is to merge the knowledge of WP2 (catalyst) and WP3 (membranes) to build up and test an OCM membrane reactor, thus providing useful information to quantify the benefits of this configuration when compared to conventional ones (an increase in the overall C2 performance together with an easier heat management is expected). To satisfy these objectives, membrane reactor experiments at different OCM conditions were carried out with several modifications to optimize the process. In addition, post characterization tests have been performed to the used samples to better understand the mechanism governing the OCM reaction under the applied conditions.

WP5 Prototype design and build
The MEMERE technology aimed towards a more efficient and flexible process for ethylene production via OCM reaction. The OCM reaction has been studied for decades though it has not yet proven economical superiority compared with conventional alternatives. In the MEMERE project the use of oxygen permeation membranes are envisaged as a key technological advancement that can increase the yield of the reactor, improving the performance of the overall process.
The reactor together with the catalyst from WP2, the membranes from WP3, and the balance of plant components were assembled within task T5.3. Besides the mechanical construction of the reactor, the setup and assembly of the system control unit was performed.

WP6 Prototype testing and validation
Work package 6 was focused on the testing and validation of the pilot scale membrane reactor. The reactor, BOP and auxiliaries were assembled in WP5, where the system was also integrated with the oxygen enriched air generator. Performance, reliability, controls response, and sensitivity to operating conditions were evaluated during the testing of the OCM reactor.
The pilot scale OCM reactor was tested under varied operating conditions.

WP7 System Design and Modelling
The activities of WP7 from month have been focused on the the mass and energy balances of the different cases investigated, a complete thermodynamic analysis comparison, a final cost estimation, and the submission of the deliverable 7.2 and 7.3. The four cases investigated are the naphtha steam cracking as benchmark technology, the conventional OCM with direct co-feeding of CH4 and oxygen, the innovative case with oxygen distribution along porous membranes, and finally the MEMERE case, where oxygen is separated and distributed using oxygen transport membranes immersed in the catalytic OCM reactor. All these cases have been implemented first in Aspen Plus; and have been subsequently optimized in order to find the optimal configuration.

WP8 Environmental LCA and economic assessment
The objective of WP8 for was to finalize all deliverables listed in the proposal. The Life Cycle Assessment (LCA) was carried out for four technologies
The assessment included sensitivity analysis, where two new scenarios have been added to see how sensitive the results are; MEMERE technology with lower yield and C1 utilization integration technology.

WP9 Dissemination and Exploitation
Intensifying the exploitation and disseminating phase was the main activity that have been scheduled and performed in this work package (WP9) in the project.
The main results of MEMERE beyond the state of the art can be summarized as:
Development at kg scale of active OCM catalysts that are stable under OCM in membrane reactor (i.e. with low oxygen content).
Development of structured catalysts for OCM reaction. both microspheres and 3D printed catalysts were produced and tested
Development of porous MgO tubes with quality for membrane reactors.
Development of single phase, dual phase and three-phase O2 selective membranes for O2 separation ond feeding.
Deveopment of reactive air brazing for sealing of both types of membranes
Design of optimized membrane reactors for high OCM C2 yields.
Techno-economic and LCA analysis of the system
First time deveolpment and testing of OCM membrane reactor at TRL5