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Urea production

Urea is an important raw material for many different industries. Due to its high nitrogen content, urea is used as a fertilizer and as a feed additive in agriculture. Urea plays also an important role in the chemical and pharmaceutical industry. Applications include for example the production of resins and melamine as well as the production of personal care products.

The production of urea is performed directly in conjunction with the ammonia synthesis because the base materials are liquid ammonia and carbon dioxide. The combination of both methods allows a resource-saving production. The inline measuring method LiquiSonic®allows the urea concentration measurement at any time and guarantees an optimal effi ciency of the urea production.

LiquiSonic® sonic velocity measurement in Urea


Urea is prepared by numerous methods. A technical possibility to synthesise urea is the thermal conversion of ammonium carbamate, which is obtained from ammonia (NH3) and carbon dioxide (CO2) at a temperature of 200 °C and a pressure of 130 to 200 bar. 

The reaction mixture (ammonium carbamate and urea) is expanded to atmospheric pressure and seperated from ammonium carbamate in distillation columns at 70 ° C. The reaction does not proceed completely. Therefore the residual ammonium carbamate is decomposed by stripping CO2 in the base materials of NH3 and CO2 which are then returned to the reactor. The urea solution is evaporated and the urea is crystallized under vacuum. For further processing, the crystallized urea is centrifuged and dried.


The LiquiSonic® immersion sensor is easily installed into the transport pipeline (typically DN80) after the decomposer. The robust sensor construction and the optional special materials, like HC 2000, promote long process life. By using the LiquiSonic® controller 30, up to four sensors can be connected, allowing the simultaneous monitoring of several measuring points.

Typical measuring range:
concentration range: 0 to 100 wt%
temperature range: -10 to 140 °C

Customer value

LiquiSonic®enables a reduction of labor cost through the elimination of manual process steps: 

  • time saving: 1 h per day

LiquiSonic®ensures an optimal and resource-saving production and increase the productivity.