(514d) Hydrogen Production from Liquid Hydrocarbons with Process Intensification – a Case Study

Driven by the need to conserve fuel resources while minimizing the carbon footprint of energy consumption, higher efficiency and lower emission technologies are being developed for both transportation and power generation markets. Among the various technology options being investigated, hydrogen emerges to become an important component of the future energy mix. One of the key challenges for hydrogen to reach an acceptable level of market penetration is to achieve significant reduction in the production cost. One approach is to reduce the capital cost by reducing the complexity of the process and thus minimizes the equipment needed to generate hydrogen.

A process concept that integrates all key operating (reaction, separation, and purification) steps involved in the hydrogen production process in a single reactor is being investigated. The overall integrated hydrogen production process using liquid hydrocarbons involves a pre-reforming step to produce a methane-rich stream followed by steam reforming and separation using a catalytic membrane reactor. Selective removal of hydrogen from the reaction environment using membranes also allows overcoming the thermodynamic equilibrium limitation for the reversible hydrogen production reactions. The membrane reformer then reforms the mixture and produces high-purity hydrogen via membrane permeation. The thermodynamic limitation is overcome by continuous removal of hydrogen from the reaction environment. The integrated process design will be compact due to elimination of water-gas shift reactors and pressure swing adsorption with improved process efficiency and reduced carbon footprint. In this study, iso-octane and heavy naphtha feeds were reformed in a lab-scale reactor to acquire preliminary insights on the industrial pre-reformer. The process optimization for operating parameters was also conducted on the entire system by building a process model in Aspen Plus. The lab-scale pre-reformer used a Ni-Ru/CGO catalyst and had a temperature range of 500 - 600°C, steam-to-carbon ratios of 2.5 and 3.0, gas-hour-space velocities (GHSVs) from 5,000 to 10,000 h^-1, and pressure from 1 to 30 bar. The process model and experimental findings will be discussed during the presentation.