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US 4,728,506 AGranted
Start-up method for ammonia plants
AssigneeCatalyst Services, Inc.
InventorsRobert Habermehl, Donald Gill
Life of this patent
Estimating the term…
Abstract
Low energy start-up procedure for ammonia plants which employs ammonia as the start-up media, thereby avoiding the BTU loss associated with venting unconverted hydrocarbons and the threat to catalyst beds associated with rapid buildup of temperatures therein.
Claims7
In a start-up procedure for a plant comprising in sequence at least one reformer stage, a CO conversion stage, a CO.sub.2 removal stage and a methanization stage;
- wherein said plant synthesizes a hydrogen-containing synthesis gas from a stream of hydrocarbon feedstock and reforms the thus produced hydrogen containing synthesis gas at least partially into recoverable ammonia, the improvement wherein a gaseous stream of ammonia is employed as the start-up media during the start-up procedure by introducing the ammonia into the reformer stage to form an ammonia containing start-up synthesis gas, passing the ammonia containing start-up synthesis gas through a start-up heater, thereby heating the ammonia containing start-up synthesis gas with said start-up heater and cycling the thus heated ammonia containing start-up synthesis gas through the sequential stages of the plant until the plant is brought to operating temperature.
An improvement in start-up procedures for a plant used to produce ammonia wherein the plant includes sequentially:
- a primary reformer, a secondary reformer, at least one stage of a CO converter, a CO.sub.2 removal system, a methanator, an ammonia synthesis converter, a fuel-fired start-up heater and a gas compressor;
- the gas compressor having a line connecting the output thereof to the input of the primary reformer to form a first circulating loop and connecting the output of said primary reformer to the input of the ammonia synthesis converter to provide a second circulating loop, the plant producing ammonia by routing preheated desulfurized hydrocarbon gas, steam and air in succession through the plant;
- the improvement in start-up procedures comprising:
- a. heating the primary reformer with steam to a temperature sufficient to dissociate vaporized ammonia into ammonia synthesis gas;
- b. providing an ammonia start-up synthesis gas by feeding vaporized ammonia and steam into the heated primary reformer to produce ammonia synthesis gas, and
- c. using the ammonia synthesis gas thus produced to heat the plant to operating temperature by circulating the thus heated ammonia synthesis gas through the first circulating loop and the second circulating loop.
3 more elements
Dependencies are inferred from the claim text.