Process intensification for hydrogen production from ammonia

Abstract

Ammonia is presented as one of the main carriers for the transport and storage of hydrogen under mild conditions. In this context, the present work introduces the integration and intensification of an ultrapure hydrogen production process from ammonia as a feedstock. A production scale is set to satisfy the requirements of a typical hydrogen refueling station (200 kgH2/day). A multifunctional shell-and-tube reactor is designed to carry out the ammonia cracking reaction. The system operates at a moderate pressure (8 bar) and in a temperature range for the ammonia decomposition reaction between 300 °C and 650 °C. Total ammonia conversion is achieved due to the chemical equilibrium shift by H2 extraction through the incorporation of 100 % selective membranes. The Pd-Ag membranes provide a recovery of about 86 % of the hydrogen produced. The remaining hydrogen (i.e., the non-permeated stream) is catalytically combusted representing the only source of heat of the entire process.