US 12,203,795 B2
Method and system for measuring a liquid level in a pressure vessel of a urea synthesis plant
Luca Rugnone, Como (IT)
Assigned to Casale SA, Lugano (CH)
Appl. No. 16/764,726
Filed by Casale SA, Lugano (CH)
PCT Filed Nov. 6, 2018, PCT No. PCT/EP2018/080264
§ 371(c)(1), (2) Date May 15, 2020,
PCT Pub. No. WO2019/096623, PCT Pub. Date May 23, 2019.
Claims priority of application No. 17202123 (EP), filed on Nov. 16, 2017.
Prior Publication US 2021/0172785 A1, Jun. 10, 2021
Int. Cl. G01F 23/284 (2006.01); G01S 13/88 (2006.01)
CPC G01F 23/284 (2013.01) [G01S 13/88 (2013.01); Y02P 20/54 (2015.11)] 21 Claims
OG exemplary drawing
 
1. A method for measuring a liquid level in a pressure vessel of a urea synthesis plant, the method comprising:
emitting a first electromagnetic signal from above the liquid level and towards the liquid level, over an outside surface of a wave guide, wherein said wave guide is an elongate solid rod, wherein the solid rod extends below the liquid level;
detecting a second electromagnetic signal which is generated by the first signal reflected by the surface of the liquid;
determining the liquid level on the basis of the elapsed time between the emission of the first signal and the detection of the second signal,
wherein a gaseous phase contained in the pressure vessel above said liquid level, which is a gaseous phase including ammonia and carbon dioxide, has a pressure equal to or greater than 80 bar and a temperature equal to or greater than 120° C., wherein the determination of the liquid level comprises a step of a compensation of a dielectric of said gaseous phase.