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.