Colloquia

Samenvatting

Hydrogen production is essential for the global transition to sustainable energy. Today, most hydrogen is produced from fossil fuels, mainly through steam methane reforming, an efficient but carbon-intensive process that emits large amounts of CO₂. To meet global decarbonization targets, new hydrogen production methods based on renewable energy and low-carbon feedstocks are needed.

This work investigates a new way to produce hydrogen sustainably by integrating autothermal reforming (ATR) of biogas with a proton exchange membrane (PEM) electrolyzer. ATR combines steam reforming and partial oxidation in a single reactor, offering high efficiency and operational flexibility, which makes it particularly suitable for dynamic operation with variable renewable inputs. While in conventional ATR systems pure oxygen is supplied by an air separation unit (ASU), an expensive and energy-intensive component, in the proposed system, the PEM electrolyzer replaces the ASU and supplies the ATR directly with oxygen produced during water electrolysis. Furthermore, heat integration can be achieved by utilizing the heat rejected by the ATR plant to heat the electrolyzer water feed. 

A dynamic model of the ATR plant was developed and validated against data from the literature. The model includes the main reactors and heat exchangers and was used to evaluate both steady-state and transient behavior. The integrated system was tested under realistic, fluctuating operating conditions based on a one-year wind profile reflecting the power output of a wind farm supplying the electrolyzer. Results showed that the ATR maintained stable temperatures, pressures, and conversion levels, confirming that it can operate safely and efficiently despite variable inputs from renewable energy.

Beyond technical performance, the study assessed economic and environmental aspects. Replacing the air separation unit with the electrolyzer significantly reduces capital and operating costs, improving project profitability. When powered by renewable electricity and fueled with biogas, the system achieves high efficiency and low carbon intensity, comparable to or better than best-available hydrogen production technologies. With future integration of carbon capture, near-zero or even carbon-negative operation could be achieved.