Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification

Abstract

Palladium-based catalytic membrane reactors (CMRs) effectively remove H2 to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H2, CO and CO2. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H2O, CO2 and H2. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H2 and induce higher methane and CO conversions while yielding ultrapure H2 and compressed CO2 ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H2 permeance and purity, high CH4 conversion levels and reduced CO yields.

Hydrogen production from coal-derived syngas undergoing high-temperature water gas shift reaction in a membrane reactor

“…As pointed out in the studies, hydrogen diffusion through the Pd membrane is the rate limiting step, and Sieverts law is usually adopted to describe the hydrogen flux through the membrane, where δ is the membrane thickness, Q 0 is the membrane hydrogen permeability constant, E m is the apparent membrane activation energy, and and are the hydrogen partial pressures on the reaction and permeate sides, respectively. The hydrogen permeation flux can also be presented as the product of the membrane permeance K p and driving force .…”

“…The WGSR‐MR has been studied extensively in the literature . However, most of these studies focused on the low operating temperature ranges such as those for traditional 2‐stage shift reactors.…”

“…The WGSR-MR has been studied extensively in the literature. [8][9][10][11][12][13][14] However, most of these studies focused on the low operating temperature ranges such as those for traditional 2-stage shift reactors. Because the syngas from the gasifier is in a high temperature and pressure state, it would be beneficial if the WGSR-MR could be integrated immediately after the gasifier.…”

Operation Optimization of Steam Accumulators as Thermal Energy Storage and Buffer Units

“…Steam has been used as a heating or power source in various industries, including chemical, dyeing, pharmaceutical, and electrical industries [1][2][3][4]. However, some steam is discharged directly into the atmosphere due to underdeveloped equipment and recovery techniques.…”

Development of a Catalytic Fuel Processor for a 10 kW Combined Heat and Power System: Experimental and Modeling Analysis of the Steam Reforming Unit

“…Preliminary investigations within the research project and previous studies from the literature on catalysts (e.g., mixed oxides vs. noble metal based catalysts) [14,15], reactor designs (packed bed of pellets vs coated monoliths or foams) [16][17][18][19], fuel processor solution and layout (partial oxidations vs. steam reforming, H2 purification stages vs. membrane reactors) [19][20][21][22][23][24], have led to the configuration schematically represented in Figure 1. Natural gas and H 2 O are fed to a steam reformer unit, heated by the burner which is co-fueled by the proton-exchanged membrane (PEM) stack tail gas.…”