This paper covers the technical and commercial features of Haldor Topsoe's CO from CO 2 technology. Haldor Topsoe's eCOs is a solid oxide electrolysis cell (SOEC) technology that allows the safe, efficient, and cost-competitive production of carbon monoxide directly at the site of facilities where the gas is needed. The CO-generation device uses feedstock carbon dioxide and electrical power to produce CO in quantities ideal for most operations that today rely on cylinder or tube trailer supply.An eCOs Plant is delivered as a stand-alone unit with power, CO 2 and product gas connections. Furthermore, the plant ensures high levels of purity, producing CO at 99.5% assay with minimal contaminants and CO 2 as the main impurity. An eCOs solution can also be customized to produce CO at 99.995% purity. One eCOs plant is able to deliver between 10 and 100 Nm 3 CO gas per hour. Several plants can be operated in parallel if larger quantities are needed.The patented eCOs technology ensures security of supply, eliminates the need to transport hazardous gas, and drastically reduce costs related to storage, rentals and connections. In the longer run, this technology opens up for a whole new segment of green and sustainable chemicals from renewable carbon sources.Field test results from the 12-kW demonstration-unit located in Houston, Texas are reported, as well as progress towards the 300-kW commercial unit to be delivered in 2018. Results from a 50-kW H 2 O electrolysis unit located in Foulum, Denmark used for biogas upgrading are also presented.

Haldor Topsoe considers SOEC as an enabling technology for the electrification of the chemical industry. Here, we present status updates on our two stepping stone projects, CO2 electrolysis for CO production and H2O electrolysis for biogas upgrading, as well as a roadmap for the electrification for production of ammonia. Compared to other electrolysis technologies, SOEC allows for the conversion of CO2 into useful chemicals at very high efficiencies and at a faradaic yield of 100%. Haldor Topsoe has commercialized the CO2 electrolysis technology under the tradename eCOsTM: a platform for on-site, on-demand CO generation from CO2 feedstock. System-level synergies found in integrating the endothermal SOEC process with an exothermal chemical synthesis process can lead to very high conversion efficiencies. At a pilot plant located at Foulum, Denmark, H2 produced from steam by SOEC is used for upgrading CO2 in biogas into pipeline quality synthetic natural gas (SNG). It is Haldor Topsoe’s ambition to become a technology provider for electrified ammonia plants and a roadmap highlighting the key milestones towards SOEC + Haber-Bosch plants in 2030 will be presented.

Haldor Topsoe is commercializing a system for on-site CO generation based on solid oxide electrolysis technology (eCOs Plant). The standard system is capable of producing CO at 99.5% purity, but can also be customized to produce CO at 99.995% purity. In this patented system, the electrochemical conversion of CO 2 into CO is carried out in solid oxide stacks, each stack producing approximately 1.5 Nm 3 CO/h. In contrast to SOFC operation, the performance of a stack operating in electrolysis mode is not exclusively determined by the area-specific resistance (ASR). While resistance determines the overall efficiency of the stack, other parameters, such as the purity of the produced gas, can be more critical in a commercial system.A systematic approach to screening and evaluating stack and celllevel improvements is presented. Several stack tests were carried out for 2000 hours at a reference operating point and then intentionally stopped to evaluate the extent of degradation in stacks and to qualify/disqualify different design modifications. The described approach was used to significantly improve stack robustness and lifetime in CO 2 electrolysis. Finally, some unsolved issues are presented, in order to spur discussion on lifetimelimiting issues specific to electrolysis.

Large footprint (144 cm 2 ) cells with infiltrated (La 0.6 Sr 0.4 ) 0.95 FeO 3 /yttria-stabilized zirconia (LSF-YSZ) cathodes were fabricated on a pre-production scale (approximately 90 cells/batch). The excellent electrochemical performance of the cells was confirmed both on single cell as well as on stack level. Changes in electrode properties were mapped out as a function of heat-treatment temperature. The microstructure of the porous zirconia backbone remained unchanged, but the surface area of the ferrite phase decreased gradually, as the electrode was treated to higher temperatures. Changes in surface area were accompanied by corresponding changes in pore size and total pore volume. In contrast to traditional composite electrodes, the in-plane conductivity of infiltrated LSF-YSZ cathodes decreased with increasing sintering temperature, a trend likely explained by microstructure alterations during the sintering of the non-random structure. Recently, the use of infiltration as a method for solid oxide fuel cell (SOFC) electrode preparation has gathered significant scientific interest.1-6 The infiltration (or impregnation) method resembles the wet impregnation and incipient wetness methods employed in heterogeneous catalysis. 7,8 The electrodes are prepared by the introduction of perovskite precursors (e.g. in the form of nanoparticles, aqueous nitrate solutions, or molten salts 9 ) into sintered porous backbone structures, typically made of electrolyte materials such as yttria-stabilized zirconia (YSZ) 1,9-12 or doped ceria. 3,6,13 Such electrodes have several advantages over traditional SOFC electrodes. Infiltration approach allows for the use of a wider range of active materials.1,2,10,12,14 Furthermore, infiltrated electrodes promise improved mechanical properties over traditional electrodes due to the lower thermal expansion mismatch between the electrolyte and cathode layers, 1,10 and enhanced performance due to the high surface area of the active phase. 1,6,12,16 Finally, the possibility of synthesizing the electrode active phase in situ within the electrolyte pores from relatively cheap nitrate precursors may offer significant materials cost advantages over traditional electrodes, where expensive perovskite powders with finely tuned particle size distributions are required for screen-printing. 17The results on infiltrated electrodes reported in the literature have so far been obtained almost exclusively on button cells with electrode active areas on the order of 1 cm 2 or less. A notable exception is the work by C. S. Ni et al., who have recently fabricated and tested 5 × 5 cm 2 cells where both the anode and the cathode was prepared by infiltration. 18 Here, we report the physical characterization and stack testing of 12 × 12 cm 2 planar cells with cathodes prepared by infiltration of a perovskite precursor solution into a stabilized zirconia (SZ) backbone. The results reported here were obtained primarily on infiltrated (La 0.6 Sr 0.4 ) 0.95 FeO 3 (LSF)-SZ electrodes. LSF-SZ is an excellent model sy...

Haldor Topsoe has commercialized a system for on-site CO generation based on solid oxide electrolysis technology under a tradename eCOs™. A single eCOs™ module is capable of producing 96 Nm3 CO per hour at 99.5% purity, and larger units consisting of several modules and higher CO purities are available on demand. In this patented system, the electrochemical conversion of CO2 into CO is carried out in solid oxide electrolysis stacks. The parameters used to evaluate the performance of SOFC stacks typically include area-specific resistance (measured in Ω cm2 cell area), stack efficiency (measured in %), stack cost (e.g. USD/kW or USD/stack), degradation rate (typically measured in %V/1000 h), and stack lifetime (measured in hours). It is common practice in the field to use the above performance metrics also to describe stacks operating in SOEC mode. This manuscript will highlight how this practice may provide a skewed picture of stack performance, and that for the commercialization of SOEC technology, a number of additional performance metrics need to be considered. In particular, the importance of lifetime capacity, i.e. the total amount of product produced by a stack (measured e.g. in Nm3 gas or mol product per stack), is highlighted. Examples of alternative ways to maximize stack lifetime capacity will be described.