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Dense membranes for efficient oxygen and hydrogen separation

Final Report Summary - DEMOYS (Dense membranes for efficient oxygen and hydrogen separation)

Executive Summary:
Membranes for oxygen and hydrogen separation are expected to play a key-role in the development of CO2 emission-free coal or natural gas power plants. Moreover, cost-effective oxygen and hydrogen production processes are needed in gas supply industry. Therefore world-wide R&D activities are focused on the development of cost-effective membranes, with higher permeability and long-term stability in the operating environment.
In this frame the main objective of DEMOYS is the development of thin mixed conducting membranes for O2 and H2 separation by using a new deposition technique “Low Pressure Plasma Spray – Thin Film” (PS-TF) in combination with nano-porous, highly catalytic layers.
PS-TF is a proprietary technology developed by Sulzer Metco, which stands between the conventional thin film technologies, such as Physical Vapour Deposition (PVD) and Chemical Vapour Deposition (CVD), and the conventional thermal spray technologies. The PS-TF process, by operating at pressures below 2 mbar, allows the cost-effective production of thin, dense coatings on large areas at low substrate temperatures.
The first part of the project has been mainly focused on material and process development, in order to evaluate the feasibility of preparing dense membranes by using the PS-TF process, while in the second part membranes were tested in laboratory pilot loop and their potential for integration in power plant with CCS has been assessed.
More in detail, Lanthanum-Strontium-Cobalt-Iron oxide (LSCF) and Lanthanum Wolfram Oxide (LWO) have been selected as reference materials for O2 and H2 separation membranes, respectively. Several batches of powders of these materials with physico-chemical characteristics suitable for the PS-TF process have been manufactured. Deposition tests with these powders have been performed on planar ceramic and metallic porous support materials. Best results have been obtained with LSCF powders on metallic supports and, therefore, development has been focused on such a type of membrane. Moreover membrane testing evidenced that the development of a support with proper characteristics is a key issue in order to obtain a dense and stable membrane. To this purpose a porous material based on a NiCoCrAlY-alloy has been developed and manufactured by gravity sintering. Dense and stable LSCF membranes, 50 micron thick, have been obtained on such a support properly modified with a LSCF functional porous layer. These membranes have been tested at lab level up to 950°C and, in addition to high selectivity and stability at temperature, showed permeation rates among the highest measured ever measured for a LSCF membrane.
A modelling study concerning the integration of the developed membranes in power generation and/or hydrogen production plants has been also performed. This study provided inputs for process scale-up and cost evaluation in selected plant configurations in order to approach zero CO2 emission and minimize CO2 capture cost. More in detail the cost estimate of electricity and CO2 capture has been focused on oxygen transport membranes (OTM) in coal-based power plants. The primary conclusion is that their integration in power plants with low carbon emissions has the potential to be more cost effective than benchmark plants using the leading CO2 capture technologies. The capital cost of an OTM-based unit is from about 20% to 35% lower than the equivalent cost of standard cryogenic Air Separation Unit, respectively for IGCC and CFB power plants. The Levelized Cost of Electricity (LCOE) and the CO2 avoidance cost (CAC) of the OTM-based plants are lower than those of plants using benchmark CO2 capture technologies. This is particularly evident for the CFB-based plants, for which the LCOE and the CAC are respectively 12% and 27% lower than the reference oxy-combustion plant with CO2 cryogenic purification unit. Additionally, the use of OTM in niche applications, i.e. oxygen and electric power co-production in plants with micro-gas turbine generators, has been assessed. Results indicates that OTM-based plants have the potential to be more cost effective than benchmark Pressure Swing Adsorption (PSA) or Vacuum Swing Adsorption (VSA) plants.

Project Context and Objectives:
provided in the attached publishable summary, along with figures
Project Results:
provided in the attached publishable summary, along with figures
Potential Impact:
provided in the attached publishable summary, along with figures
List of Websites:
http://demoys.rse-web.it/

contact details provided in the attached publishable summary.