Process Integration Analysis of an Industrial Hydrogen Production Process
The energy efficiency of an industrial hydrogen production process using steam methane reforming (SMR) combined with the water gas shift reaction (WGS) is analyzed using process integration techniques based on heat cascade calculation and pinch analysis with the aim of identifying potential measures to enhance the process performance. The challenge is to satisfy the high temperature heat demand of the SMR reaction by minimizing the consumption of natural gas to feed the combustion and to exploit at maximum the heat excess at low temperature by producing valuable steam or electricity or by performing cogeneration. By applying a systematic methodology based on energy-flow models, process integration techniques and a multi-objective optimization procedure, the process performances defined by the specific natural gas consumption and the specific steam or electricity production is optimized and analyzed for different operating conditions (i.e. air preheating, pre-reforming/reforming, WGS temperature) and process modification options like pre-reformer integration. Identified measures are to increase the production of exportable steam by consuming the entire waste heat and optimizing the steam production pressure level, and to reduce the natural gas consumption by adjusting process parameters. By these measures the performance can be varied between 0.53-0.59 kmol natural gas/kmol H2 for the specific total natural gas consumption and 1.8-3.7 kmol steam/kmol H2 for the specific steam production.