Combined hydrogen and oxygen transport ceramic membranes for methane dehydro-aromatisation

Lead Research Organisation: Queen's University of Belfast
Department Name: Sch of Chemistry and Chemical Eng

Abstract

The costs-effective separation of high purity hydrogen at high temperatures (above 500 degC) is an important step in many industrial processes such as methane reforming, biomass gasification etc. Hydrogen transport membranes are ideally suited for such operations as they can provide high selectivity towards hydrogen transport and when coupled with appropriate catalysts in a catalytic membrane reactor they can combine the reaction and separation step in one processes thus minimising the overall process footprint, energy, utilities requirements and ultimately cost. In addition to hydrogen removal, for reactions where catalyst deactivation due to carbon deposition is an issue, the continuous and distributed supply of oxygen to provide in situ catalyst regeneration would be highly beneficial. Ceramic membranes that exhibit protonic, oxygen ion and electronic conductivity are ideally suited for such applications and would find use in processes such as methane steam reforming, methane coupling and aromatisation to name but a few. In this project we will investigate the development of high temperature ceramic hydrogen and oxygen transport membranes to be used in membrane-based methane aromatisation with combined catalyst regeneration. The employed membranes must be both mechanically and chemically stable at the required temperature of operation and reaction conditions, providing high selectivity towards hydrogen permeation with concomitant high hydrogen fluxes.
Despite the huge potential methane presents as a feedstock material for chemical synthesis, to date the most widespread use of methane is as a fuel, while its use as a chemical feedstock is mainly limited to methane reforming for the production of synthesis gas and hydrogen (methane reforming is the most mature technology to date for the production of hydrogen). In addition, natural gas is still wastefully flared resulting in unnecessary greenhouse emissions with a concomitant resource waste. At UK-based oil platforms emissions due to natural gas flaring amount to 2.9 million cubic meters per day- equivalent to approximately 3% of the yearly total UK gas gas production. It has been noted that the largest amount of gas flared in association with oil production is a direct result of the lack of infrastructure for its utilisation. Therefore, the development of a viable process for utilisation of methane (as the main constituent of natural gas) will be of great benefit, in particular with meeting the UK Government's target of reducing CO2 emissions by 80% by 2050. The proposed project aims to demonstrate the feasibility of a membrane-based methane aromatisation process with significant benefits for the research community and the oil and gas industry both in the participating countries and worldwide. This project links together several aspects of materials science and chemical engineering e.g. membrane stability under real operating conditions and optimisation of a catalytic process of industrial interest, while working towards a practical solution of the very interesting problem of methane utilisation.

Planned Impact

With respect to the potential socio-economic impact of the proposed project we have identified three groups of beneficiaries classed according to the immediacy of the benefits received as a result of the project. The mechanisms in place to achieve the desired impact outcomes will be discussed in the 'Pathways to Impact' section
1. Immediate to short-term benefits (< 5years): Researchers involved in the project and chemical engineering undergraduate students at the School of Chemistry and Chemical Engineering at QUB.
The most immediate beneficiaries of the proposed project have been identified as the researcher directly involved in the work. The PDRA will work in a research environment in a Russell Group University, while working on a cutting edge research project. He/she will become competent in a wide range of analytical, experimental and modelling techniques thus improving significantly their employability at the end of his PhD. In addition, he/she will develop new skills both in terms of research and personal development. The PDRA will be encouraged to participate in international conferences and attend training workshops both with respect to their research but also as part of their personal development.
In addition, undergraduate students in chemical engineering will benefit from this work. It is envisaged that at least four final year MEng and BEng students will conduct their final year research project in areas relevant to this project under the supervision of the PI. These students will be exposed to the working ethos of a research project and will gain valuable experience for their future career. The findings from this work will also be incorporated into the undergraduate teaching, where relevant, in particular in the final two year of.
2. Medium term benefits (5-15 years): Companies involved in the oil and gas, ceramic materials and separation process industries.
For the 5-15 year period after the completion of the project the potential beneficiaries have been identified as companies active in the oil and gas, ceramic materials, and separations sectors both in the UK and globally. Examples include companies such as BP, Perenco, Praxair and Air Products will be recipients of such technology. Companies active in the oil and gas industry will benefit from the delivery of a final product/solution for membrane-based methane activation to be used either as a direct route for methane exploitation (with the view to steer away from synthesis routes based on oil derivatives) or as an alternative route to natural gas flaring at oil platforms and terminals. Companies that are active in the areas of functional ceramics and gas phase separations will benefit from the intermediate steps of the project, namely material development. The developed materials will be relevant to a multitude of additional applications such a hydrogen purification, solid oxide fuel cells and electrolysers.
3. Long term benefits (>15 years): The UK economy and public
In the long term the UK economy and public stand to benefit from the technology developed in this project. Successful implementation of this technology will see the reduction of CO2 emissions from unnecessary flaring at oil and gas terminals and platforms, thus improving the air quality and aiding the UK government to achieve their target of 80% CO2 emissions reduction by 2050. In fact this project and any follow on work comes at a crucial point in the timeline of measures required to achieve this reduction target. Reduction of CO2 emissions will also lead to further potential economic benefits for the UK public, as it will become possible for the government to sell redundant CO2 credits to emerging economies, thus enabling economic growth that will improve the quality of life for the British public. Moreover, the technology developed here can put the UK in a lead position in the global oil and gas market as the IP holder.

Publications

10 25 50
 
Description The aim of the project was to develop a ceramic membrane reactor for the activation reactions of methane (to aromatic compounds and higher hydrocarbons). In order to deliver this we had to investigate the development of the appropriate ceramic materials with simultaneous oxygen and hydrogen transport properties. This would enable the catalytic dehydrogenation of methane to take place in the membrane reactor with continuous hydrogen removal (to increase conversion) and oxygen supply (to combat catalyst poisoning due to carbon deposition, a known problem of these reactions).The main findings of the project lie on the development of the appropriate membrane reactor materials. Work focused on increasing the stability of the membrane in CO2 and H2O containing atmospheres (both compounds would be present under operating conditions). The use of a novel membrane preparation technique using microwave sintering allowed us, for the first time, to prepare Y- and Zr-doped barium cerates - BCZY (known for their good combination of protonic mobility and stability) using sintering temperatures of 1100oC. In addition, dual phase membranes of BCZY and CeGdO (used to increase the electronic conductivity of the materials and thus enhance the hydrogen and oxygen transport properties without the need for an external circuit, thus simplifying the overall reactor design) were also prepared using this novel technique. In parallel, hollow-fibre single- and dual-phase membranes were successfully prepared in Tianjin University to be used in the catalytic experiments. The transport properties of the membranes were tested and a model of the operation under methane dehydrogenation conditions was prepared. Results from the project will be presented at the 25th International Symposia on Chemical Reaction Engineering in Florence (May 2018). In addition, work on the use of the developed membranes in the catalytic hydrogenation of CO2 to hydrocarbons in currently underway.
Exploitation Route Ceramic membrane preparation methods using microwave sintering were developed as part of this project can be used by other researchers in this area. This can simplify significantly the requirements of high temperature sintering furnaces for the preparation of dense ceramic membranes with potential benefits in a wide range of research areas (e.g. solid oxide fuel cell, ceramic membrane reactors, functional ceramics etc.)
Sectors Energy,Environment

 
Description Collaboration with Tianjin Technical University 
Organisation Tianjin University
Country China 
Sector Academic/University 
PI Contribution Fabricate membranes for CH4 aromatisation
Collaborator Contribution Collaboration set up as part of the project. Professor Tan Xiaoyao was due to host the PDRA working on this project for a period of two months in order to prepare the HF membranes needed for the catalytic work. Due to delays in the delivery of the raw materials the collaboration had to change shape. Prof Tan Xiaoyao instead successfully prepared the ceramic membranes.
Impact HF membranes successfully prepared at Tianjin
Start Year 2015
 
Description 2 poster presentations at the 25th International Symposia on Chemical Reaction Engineering 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This will take place in May 2018
Year(s) Of Engagement Activity 2018
 
Description Electrochemical Promotion of CO Oxidation on Pt/BCY: The case of a mixed proton-oxygen ion conductor 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Oral presentation at the 21st International Conference on Solid State Ionics
Year(s) Of Engagement Activity 2017
 
Description Oral Presentation at the 2018 UK Catalysis Conference: Electrochemically assisted reactions on alkali-modified precious metal catalysts 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Discussion after presentation
Year(s) Of Engagement Activity 2018
 
Description Oral presentation at the 2017 UK catalysis Conference: Electrochemical Promotion of CO Oxidation on Pt/YSZ- Interaction between Multiple Promoting Species 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Other audiences
Results and Impact Oral presentation on project progress at the UK Catalysis conference January 2017
Year(s) Of Engagement Activity 2017
 
Description Oral presentation at the 21st International Conference on Solid State Ionics - Electrochemical Promotion of CO Oxidation by on a Dual Ion Conducting Ceramic Support 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Discussions held after talk.
Year(s) Of Engagement Activity 2018
 
Description Poster presentation at the 18th International Conference on Solid State Proton Conductors: Studies of Y-Doped Ba (Ce, Zr) O3 for Electrochemical Promotion applications 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Poster presentation initiated dicussion
Year(s) Of Engagement Activity 2016
URL http://www.sspc18.com/