Uhde three bed ammonia converter

The demand for energy-efficient ammonia production dictates the following criteria for the design of the ammonia synthesis unit:

• high conversion rates and therefore large catalyst volume;

• maximum utilization of reaction heat for the generation of high pressure steam;

• low pressure drop in the loop.

Such criteria, in turn, call for the:

• use of small grain-size catalyst;

• application of the radial-flow principle;

• high pressure steam generation wherever feasible.

The Uhde ammonia synthesis design therefore incorporates three radial-type catalyst beds arranged in either one or two ammonia converters.

Features of the single-converter design:

• heat exchanger between catalyst beds for indirect cooling of synthesis gas, consequently highly efficient temperature control;

• radial flow from outside to inside through all catalyst beds;

• design adaptable to full-bore or drawn-in top closure of converter, depending on project constraints;

• heat exchangers extractable without removal of cartridge;

• an externally-arranged BFW preheater/HP steam boiler downstream of the third bed.