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CO2 - Loop for Energy storage and conversion to Organic chemistry Processes through advanced catalytic Systems

European Union Seventh Framework Programme
FIRST RESULTS
 Home Newsletter 2 / March 2014
 

CEOPS EVENTS:

Workshop
R&D on CO2 utilization in Europe

The CEOPS project will held its first workshop on the current status of R&D on CO2 utilization in Europe on the 26th of May 2014 in the frame of the E-MRS Spring Meeting in Lille, France. Some European projects and other initiatives of this field will be presented.  More information and online registration here.



2nd Conference on Carbon Dioxide

CEOPS was presented at the 2nd Conference on Carbon Dioxide as Feedstock for Chemistry and Polymers by one of CEOPS's partners: Jörg Klein, from Chemie-Cluster Bayern GmbH. The conference took place in Essen, Germany from the 7th to the 9th October 2013. Over 100 participants and presenters discussed current state of the art technologies and around the use of CO2. The presentations ranged from academic research achieving chemical reactions with flue gas to techno-economic analysis of industrial polymers.

The topics covered will mostly become relevant in WP5 of CEOPS which just started.

 

Essen CCB

 

 

 

Project coordinator:
Laurent BEDEL
CEA-Grenoble - LITEN-DTBH
38054 Grenoble Cedex 9
France
Tél: 33-4-38-78-57-20
laurent.bedel@cea.fr 

 

CEOPS: the importance of CO2 transformation

Despite increasing investments and developments in low-carbon energy alternatives and the progressive introduction of renewable energy resources, consumption of fossil fuels and consequently of CO2, is still expected to grow significantly due to increasing worldwide energy and electricity demands partially caused by the emergence of new economic powers in the world.

From CO2 valorization standpoint, scientific, industrial and societal authorities are urged to propose new schemes for producing, consuming and recycling carbon from fossil fuels for energy market and chemical industry. In this context, valorizations of CO2 emissions constitute the main strategy to the reduction of environmental impacts.

CO2 transformation into fine chemicals and liquid fuels, as Methanol, by fixing H2 to carbon, will foster the transition from carbon fossil sources to low carbon footprint ones.

Methanol is an important and versatile building block, which can play the role of chemical storage molecule for energy and used as fuel or for the synthesis of products such as acetic acid, formaldehyde, olefins…, but also ephedrine or caffeine.

 

The concept of CEOPS

CEOPS is based on the conversion of CO2 to methane, at the point of CO2 emission, and the direct conversion of methane to methanol. Methane will act as an easy storable and transportable carbon vector (from intermittent sources).

More information on the concept here.

CEOPS is focused on the development of advanced catalysts and electro-catalytic processes for subsystems A and B. Specific catalysts are developed and evaluated to overcome the current limitations of thermal catalysis for each chemical pathway. These limitations are (i) the ageing of catalyst (acid Lewis type) mainly due to water adsorption (basis Lewis type) produced during the CO2 hydrogenation to CHwhich limits the catalyst lifetime to 5000-7500 hours, and (ii) the low conversion rate and selectivity of the direct reaction from methane to methanol.
CEOPS develops and evaluates 3 processes, DBD (Dielectric Barrier Discharge) plasma catalysis, Photo-activated catalysis and Electro-catalytic reduction. DBD plasma catalysis is implemented on fixed bed reactor (UPMC) for mechanisms studies and in parallel on a fluidized bed reactor (CEA) for performance assessment.
In this case, electrons produced by voltage pulses can collide with gas reactants, leading to their activation through their vibrational excitation and enhancing the dissociation in the surface of the catalyst. Moreover the high voltage applied leads to a significant desorption of the water vapor produces during the Sabatier reaction: CO2 + 4H2 →CH4 + 2H2O with ∆H = -165.0 kJ/mol.

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Experimental Set-up

The work is performed on zeolite based catalysts, with high dispersion of metals nanoparticles (Ni, Ru, Rh) and metal oxides (cerium oxides, zirconium oxides) and  with a control of acid sites concentration,  for an optimum desorption of species from active sites and a synergy with pulse plasma (electro polarization of catalyst). These catalysts are supplied by partners IREC and IST.
The DBD discharge reactor used in the experiments consisted of two coaxial cylinders with OD 3mm and ID 8mm. The catalyst is placed in the annular space (gap of 2.5mm), its volume is 0.5ml. Sinusoidal high voltage current around 14KV peak to peak is applied to the HV electrode. As reaction take place at high temperatures, exhaust gases are cooled in order to collect the liquid products. To analyze CO2 we use a specific detector, the other gaseous products are analyzed by gas chromatograph, FTIR and mass spectrometer. The condensable products are collected for further analysis.

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Voltage

The voltage-current waveforms in a 20% CO2/H2 mixture shows a near uniform discharge (several streamers on each half cycle) of diffuse nature. This kind of waveform for the current is probably due to discharges occurring in the bulk of the catalyst. These internal discharges increase the conductivity of the dielectric that leads to a spreading of the surface charge. The resulting streamers are shorter but their number increases significantly. Typical voltage values are 10 to 14 kV and the energy induced, at a frequency of 40 kHz, varies in the range of 20 - 35 µJ/cycle, corresponding to a power between 0.8 and 1.4 W.

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Experiments

Experiments were performed at 3 temperatures, 320,370 and 420°C with only catalyst heated and catalyst heated + electrical discharge. Total flow rate is 200ml/min, corresponding to a GHSV of 20000. The mixture is H2:CO2 = 80%-20%. Under these conditions in both cases hydrogenation of COproduces CO, CHand liquid products, which contain two phases, aqueous and organic, probably hydrocarbons. The results show in all cases (3 temperatures for all catalysts tested) an increase of conversion of CO2 in the case of the electrical discharge. CH4 is the main product, but there are also small amounts of CO. The amount of CO increases with temperature probably produced by the reverse water-gas shift (RWGS) reaction: CO2 + H2→CO+H2O, which is an endothermic so much faster at higher temperatures.
At 320°C the conversion of CO2 is about 4 times higher in the case of plasma enhanced reaction.

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Results

As a conclusion:
- Plasma assisted catalysis increases between 30 and 50% the conversion of CO2, depending on the catalyst.
- Conversions are always higher in the case of the plasma, close to 96-98%.
- Water desorption is probably the key step in this process as plasma enhances this desorption at much lower temperature.

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