Urea is the most widely used nitrogen fertilizer agent in the world. Urea is manufactured in a synthesis tower at high pressure and high temperature through a process of high-pressure synthesis from liquid ammonia and a gas-water mixture with 88.7 % CO2. This gives rise to synthetic ammonium carbamide. Dehydrating while adding acid and heating, and further processing finally yield a white granulate – the fertilizer. The high pressures required by the process are generated in multi-stage radial integrally geared compressors. Each compressor stage requires a chamber seal with barrier gas and a leakage connection. For reasons of working safety, the highly compressed CO2 must never escape from the process area into the atmosphere.

Solution from EagleBurgmann Espey:

For the 8 compressor stages, Espey developed the compact Espey WKA802HD chamber seal with barrier gas and leakage connections, and with up to 8 seal rings in up to 3 ring groups for pressures of up to 140 bar (2030.53 PSI), temperatures up to 225 °C (437 °F), and rotation speeds of up to about 40000 rpm. Nitrogen is used as barrier gas. Each of the 8 stages has a special version of the Espey WKA802HD, with different lengths, and with different seal and external diameters. The one-piece bandaged carbon seal rings are axially sprung to help deal with vibrations during the startup and rundown phases of the geared compressor. The seal solution has a long service life, is maintenance-free, and is designed for dry running.

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