Autothermal Reformer-Based Ammonia Production

A relatively new way of producing hydrogen using autothermal reforming makes carbon capture easier for blue ammonia production.

Ammonia production via autothermal reforming (ATR) of natural gas is a process that allows for larger reductions of carbon dioxide emissions compared to the more traditional steam reforming process, which involves a primary and secondary reformer. In an ATR process, most of the CO₂ emissions are concentrated in one single stream, which can be sent to sequestration.

In the ammonia industry, there are some reservations against ATR. Chiefly, as opposed to traditional steam methane reforming (SMR), oxygen is added to the ATR reactors to raise the temperature of internal combustion, which provides the energy required to reform the natural gas feed. The oxygen stream presents a potential hazard to the ammonia plant. However, in the methanol industry, the use of oxygen is a well-accepted practice.

This article discusses the lessons that one company’s engineers learned while developing an ATR-based ammonia plant. Through knowledge transfer from a methanol plant design, the proper mechanical design of the ammonia plant (including piping) and the safety systems around the ATR unit were established, which emphasized the safe handling of oxygen. This article also covers how to determine the boundaries of carbon intensity calculations — considering the plant alone (Scope 1) or including the utility supply (Scope 2) — and the impact of such boundaries on the plant’s design...