Improvement to the high-pressure loop in a process for synthesis of urea

Abstract

A process and a related plant layout for producing urea are disclosed, wherein the high-pressure loop (1) comprises a synthesis reactor (2), a thermal stripper (3), a condenser (4), and an adiabatic CO2 stripper (10) disposed upstream said thermal stripper, separating a vapour phase (13) containing ammonia from the urea solution (9) discharged from the reactor, and recycling said vapour phase to the reactor. The adiabatic stripper (10) can be incorporated in a reactor (200) having a top reaction zone and a bottom adiabatic stripping zone. A revamping method for a conventional urea plant in accordance with the inventive process is also disclosed.

Description

technical field [0001] The invention relates to a new process for producing urea. The invention provides an improvement to the high-pressure synthesis loop of the traditional process and is suitable for new equipment and for improving existing self-stripping urea production equipment and carbon dioxide stripping urea production equipment. Background technique [0002] The self-stripping process or thermal stripping process is a well-known process for the synthesis of urea. It is commonly called the Snamprogetti process and was researched by Snamprogetti in the late 1960s. A disclosure of this process and associated equipment can be found, for example, in GB1542371. Worldwide, many urea production facilities utilize this process. [0003] Basically, the self-stripping process provides ammonia NH 3 with carbon dioxide CO 2 reaction between. The nitrogen to carbon molar ratio N / C in this reactor is usually about 3.2-3.4. [0004] The aqueous urea solution containing free...

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Problems solved by technology

CO 2 The stripping process has some advantageous features but is limited in large plants especially stripping columns

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