Single train ammonia plant concept

To illustrate the forgoing discussion of the concept of the single-train steam reforming plant, Figure 105 presents a modern low-energy ammonia plant with flow sheet and process streams (UHDE process). 

From 1940 to 1950 the number of ammonia plants doubled then from 1950 to 1960 the number more than doubled again. It was in the early 1960s that the single-train concept was developed, and many smaller plants became uneconomical and were shut down. Capacity tripled in the period from about 1958 to 1968. U.S. production declined in the 1970s, and although it has leveled off at near 16 million metric tons/year, world demand continues to rise. Worldwide production, including the U.S., increased 70 percent from 1976 to 1990 to 121 million metric tons/year. 

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