OP-II-3

OP-III-B-6TESTING MEMBRANE REACTORS AT SCALE: WGS-EXPERIMENTSWITH THREE Pd MEMBRANE TUBES OF 50 cm LONGHui Li, J. Boon, J.W. Dijkstra, J.A.Z. PieterseHydrogen & Clean Fossil Fuels, Energy research Centre of the Netherlands,P.O. Box 1, NL1755ZG Petten, The Netherlands, li@ecn.nlOne attractive approach for CO 2 capture in power plants is to carry out thewater-gas shift (WGS) reaction in a Pd-based membrane reactor, where the chemicalreaction and H 2 /CO 2 product separation occur at the same time. The reactions can becarried out more efficiently as the equilibrium will be shifted due to the selectiveremoval of H 2 . When integrated in a natural gas fired power plant, these reactors allowfor power production from the hydrogen stream while simultaneously CO 2 is capturedin the retentate side and available for underground storage. Recently, ECN hasconstructed a process development unit (PDU) for testing membrane reactors. It has acapacity of 8 tubular membranes of 50 cm long and can be operated up to 40 bara and600°C. The PDU will demonstrate the feasibility of membrane reactors at a benchscale size, and at the conditions that are present in power plants with pre-combustionCO 2 capture using hydrogen membranes. It is used for testing of reactor concepts, andthe study of membrane and catalyst characteristics.The present contribution describes membrane-enhanced water-gas shift reactionwith three parallel highly perm-selective Pd composite membranes in the PDU with alength of 50 cm (44 cm effective) and with a palladium layer of ca. 5.6 µm, reaching atotal membrane surface area of 580 cm 2configuration. Working conditions were:400°C and 20-35 bar(a) feed pressure, composition: 4.01% CO, 19.24% CO 2 ,15.43% H 2 O, 1.20% CH 4 and 60.12% H 2 . Commercial noble metal water-gas shiftcatalyst was inserted at the feed side of the reactor tubes. Feed flow rate of30-90 Nl/min were used and a N 2 counter-current sweep at 15 bar was applied.The pure H 2 permeance of the three membranes was measured as2.7·10 –6 mol/m 2 .s.Pa at 400°C with a feed/permeate pressure of 2.1/1.1 bar(a) underno-sweep conditions and remained stable for 27 days during the WGS-reaction testwhile the pure N 2 permeance of three membranes was 2.6·10 –9 mol/m 2 .s.Pa at 400°C.CO conversion was observed to be far beyond the equilibrium conversion at 400°C,increased with feed pressure and decreased with feed flow rate (see Figure 1).CO conversion and H 2 recovery amounted up to 92% at a feed/sweep flow rate of190