MIT proposes hybrid blue-green ammonia production to cut emissions

MIT researchers propose combining blue and green ammonia plants to reduce production greenhouse-gas emissions by up to 63 percent versus the leading low-emissions approach; the team has filed for a patent on the combined process and published their analysis in Energy & Fuels.

• Main announcement/action: MIT (MITEI) researchers led by William H. Green, with Sayandeep Biswas, Randall Field, Angiras Menon, and Guiyan Zang, present a proposed hybrid “blue-green” ammonia plant design that colocates a blue ammonia facility (requiring pure oxygen for autothermal reforming) next to a green ammonia facility (which produces excess oxygen during hydrogen electrolysis) to reuse oxygen, improve efficiency, and reduce lifecycle emissions by up to 63%; the study includes techno-economic analysis and the team filed for a patent.
• Background and supporting details: The paper appears in Energy & Fuels and the work was supported by IHI Japan and the Martin Family Society of Fellows for Sustainability; the article contrasts blue ammonia (CO2 capture and sequestration; some plants operating in Louisiana shipping mostly to Japan) and green ammonia (electrolysis-driven hydrogen using renewables; large plant under construction in Saudi Arabia), notes shipping as a potential market pending an upcoming IMO vote, and states the concept has not yet been built and requires further engineering and start-up/shut-down studies.