Deepak Fertilizers and Petrochemicals

• Ammonia production uses about 2% of the world’s fossil fuel energy and generates more than 420 million tons of CO2 per year.

• Approximately 80% of ammonia is utilized for fertilizers, with around 5% for explosives and the balance for other chemical commodities

Ammonia Production Process: Ammonia is produced by the highly energy- and carbon-intensive Haber-Bosch process, which requires temperatures of 450–500°C and pressures of up to 200 bar.

• The feedstock for this process is hydrogen from natural gas (NG), coal, or oil, and nitrogen.

• Per ton of ammonia consumed, energy from NG, coal, and fuel oil is 7.8, 10.6, and 11.7 MWh, respectively.

Producing ammonia from renewable sources is nothing new. In the past, a number of hydropower plants synthesized ammonia using hydrogen produced from electrolysis as the feedstock. Several large-scale electrolytic hydrogen facilities have been built since 1928, when hydrogen was first produced via hydroelectric power in Norway. By the 1970s, plants in India, Egypt, Zimbabwe, Peru, Iceland, and Canada were also producing fertilizers from electrolytic hydrogen, the largest of these facilities being a 180-megawatt plant in Egypt.

However, due to falling NG prices and increasing local electricity demand, many of these plants have been closed or converted into NG feedstock-based plants for ammonia synthesis.

Ammonia can be produced by wind power. Beginning in the early 1960s, wind-powered ammonia production was investigated by the United States Army through an initiative called the “Energy Depot Concept.” Later, in the 1970s, ammonia production using wind power in a stand-alone system was extensively explored by Lockheed California Company and the U.S. National Science Foundation. While both the U.S. Army and Lockheed/NSF found that wind power could be used to produce ammonia, neither constructed a wind-powered ammonia prototype plant nor discussed the economics of building a wind-powered ammonia plant in any significant depth.

• In the renewable ammonia or Green ammonia synthesis process, hydrogen is produced by electrolysis. The required electricity is generated from a renewable source, such as solar or wind generators. The hydrogen and nitrogen from an air separation unit (ASU) are compressed to the required synthesis pressure and fed to the Haber-Bosch synthesis reactor.

• The cost of the ammonia for this route is mainly dependent on the electrolyser capital costs and electricity input costs.

• Casale, Haldor Topsoe, ThyssenKrupp, and KBR all developing designs for the integration of their ammonia synthesis technologies with renewable powered electrolyzers.