Conversion into hybrid ammonia plants
One challenge of a green revamp by stepwise injection of green hydrogen into existing ammonia/urea complexes is to cover the nitrogen demand for the ammonia synthesis while stepwise reducing the front-end load, usually by applying a cost-intensive air separation unit (ASU). thyssenkrupp Uhde GmbH has developed an advantageous concept whereby, instead of an ASU, the nitrogen gap is closed by the introduction of pretreated reformer flue gas back into the ammonia process, with the side effect to also enhance CO2 production.