Process for separating NH
The invention relates to a process for separating NH 3 from a mixture containing NH 3 , CO 2 and H 2 O which comprises an NH 3 rectification step carried out in a NH 3 separation device to which one or more streams containing NH 3 , CO 2 and H 2 O including the mixture, are supplied, with a stream consisting substantially of gaseous NH 3 being formed in the NH 3 separation device, separated from the mixture and discharged. In the process according to the invention a condensation step is carried out on at least one of the stream consisting substantially of gaseous NH 3 or the one or more streams containing NH 3 , CO 2 and H 2 O supplied to the NH 3 separation device, in which at least a part of the existing CO 2 is converted to a liquid phase.
1. Process for separating NH 3 from a mixture containing NH 3 , CO 2 and H 2 O which comprises an NH 3 rectification step carried out in an NH 3 separation device to which one or more streams containing NH 3 , CO 2 and H 2 O, including the mixture, are fed from elsewhere in the process, with a stream consisting substantially of gaseous NH 3 being formed in the NH 3 separation device, separated from the mixture and discharged, wherein a condensation step is carried out in a condenser separate from the NH 3 separation device on at least one of the stream consisting substantially of gaseous NH 3 or the one or more streams containing NH 3 , CO 2 and H 2 O supplied to the NH 3 separation device, in which at least a part of the existing CO 2 is converted to a liquid phase.
2. Process according to claim 1 , in which the condensation step is carried out by cooling the stream to be condensed and/or bringing it into contact with an absorbing medium.
3. Process according to claim 1 , the process further comprising, in order to separate CO 2 and H 2 O from the mixture:
a CO 2 rectification step, which is applied in a CO 2 separation device to the mixture coming from the NH 3 separation device while a stream coming from a desorption device is supplied, with a stream consisting substantially of CO 2 being formed in the CO 2 separation device and being separated from the mixture, and
a desorption step, which is applied in the desorption device to the mixture coming from the CO 2 separation device, with a stream consisting substantially of H 2 O being formed and being separated from the mixture, after which the mixture is returned to the NH 3 separation device and/or the CO 2 separation device,
in which the condensation step is carried out on the stream consisting substantially of gaseous NH 3 from the NH 3 separation device and/or on at least a part of the stream that comes from the desorption device and that is supplied to the NH 3 separation device.
4. Process according to claim 1 , in which the condensation step is carried out on the stream consisting substantially of gaseous NH 3 from the NH 3 separation device in a submerged condenser while an aqueous stream and/or liquid NH 3 is supplied as absorbing medium.
5. Process according to claim 4 , in which after the condensation step an absorption step is applied to the stream consisting substantially of gaseous NH 3 , in which the said stream is brought into contact with liquid NH 3 .
6. Process according to claim 1 , in which the condensation step is carried out as a partial condensation step, by means of indirect cooling with a cooling medium, on a stream that comes from a desorption device and is supplied to the NH 3 separation device.
7. Process according to claim 6 , in which the mixture present in the NH 3 separation device is used as cooling medium in the partial condensation step.