An ECN hydrogen separation membrane was recently tested for 500 hours in Italy during the FISR demonstration project. The installation produces hydrogen from natural gas and steam. Using the ECN membrane module to separate hydrogen from carbon dioxide at a high temperature increases the energy efficiency of the process by more than 10%. “A success that has greatly encouraged us to focus intensively on the Carena project that will start on 1 January 2011,” says an enthusiastic Yvonne van Delft, Project Leader at Efficiency & Infrastructure.

The reactor membrane module (RMM) had to deliver 20 Nm³ of hydrogen per hour, and did so for 500 hours without any problems. A remarkable detail of the ECN hydrogen separator is that it is combined with the reactor where the components react. It extracts hydrogen from the reforming process, which shifts the equilibrium and stimulates the reaction to produce more H₂. “Thanks to the combination, the reaction temperature can drop from 850-900 °C to 550-650 °C. This makes quite a difference in this energy-intensive process. The entire installation also becomes significantly more compact and therefore decreases investment costs for the manufacturer,” explains Van Delft.

Three-in-one installation for efficient hydrogen production

It sounds logical when expressed this way, but a long story of development work precedes this recent success. For the composite palladium (Pd) membranes in the hydrogen separator are averse to high temperatures, while the hydrogen-producing process actually benefits from a high temperature. The major achievement of ECN researchers is that they have succeeded in making the Pd membranes so strong that they will not deteriorate under the current operating temperature. Van Delft: “There is also an exceptionally thin layer of palladium on our membrane that is only 3-9 micron (µm) thick. Commercial metal filters, in comparison, have a Pd layer of 20-50 micron. The thickness of the palladium layer directly influences the hydrogen flux – the quantity of hydrogen that flows through the filter per unit of time – so this is a significant improvement.”

The compact and energy efficient membrane separator Hysep is already on the market.

Hysep on the market
The test involving the 0.4 square metre large separation filter + reactor lasted 500 hours and was conducted by Tecnimont in Italy. Two years were required to design and construct the surrounding installation on a 1000 m² site, in particular due to permits. In the meantime ECN employees in Petten were hard at work. ECN released the hydrogen filter as Hysep^® onto the market. Van Delft: “Companies can buy a demonstration version of our hydrogen filter in a few standard sizes in order to test it within their process and compare it with an existing or another separation installation. This ensures a low threshold for (petro)chemical companies and engineering firms to familiarise themselves with this new separation technology.”
Separation via membranes is fairly revolutionary in the petrochemical industry, which has separated substances via distillation for over a hundred years already. This is why Tecnimont has included the reformer and the membrane module separately in the installation. Van Delft: “This was explicitly requested by Tecnimont, which is well aware of the success factors for innovation among its customers. The membrane module has to prove itself separately first. The step towards a fully integrated system can only be taken once the hydrogen separation membranes have proven themselves as an industrial technology.”

Future
Hysep® is a pure separation filter for hydrogen, a so-called MM (membrane module). The hydrogen separator that Tecnimont successfully tested recently is an RMM (a combination of a reformer and a membrane module). In terms of development work, ECN has therefore arrived at the proof of concept phase, and Van Delft emphasises “that ECN thus occupies a unique position in the world”. That has certainly benefited the knowledge institute. “This good track record undoubtedly ensured that we were asked to coordinate the Carena project (15 partners, 12 million euros).”
Various research groups will work together in Carena and share knowledge/expertise relating to membrane reactors. Not every group is in the same phase of development work, “but that merely makes it more interesting”. Van Delft has already worked out the plans for her research. “The tests conducted by Tecnimont have revealed that the reformer can be successfully combined with the membrane module. For this long-term study, we are investigating whether our Pd separation membrane can also be fully integrated with the reformer.”
The hydrogen separating membrane that Tecnimont examined has a working surface of 0.4 m², but can nevertheless deliver over 20 Nm³/h. Future hydrogen membrane reactors are becoming larger and capacity can also be increased by connecting them in parallel. Van Delft indicates that the technology is suitable for the most energy-intensive sectors of the chemical industry. “The production of ammonia from natural gas, for example, can occur in a considerably more cost-effective and energy-efficient manner using this technology.”

Contact
Yvonne van Delft
Efficiency & Infrastructure / Process & System Technology
Tel.: +31 (0)22 456 81 78
Email: Yvonne van Delft

Info
Towards application of palladium membrane reactors in large-scale production of hydrogen, an ECN-report.

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