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US 12,522,563 B2Granted
Urea production with reduced urea losses
AssigneeStamicarbon B.V.
InventorsRahul Patil, Lambertus Wilhelmus Gevers, Chuanbo Gao
Life of this patent
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Abstract
The disclosure pertains to a urea production process wherein vapor from an evaporation unit for concentrating urea solution is condensed and the resulting process condensate, which contains urea originating from urea entrained in the vapor, is combined with a second urea solution to obtain a dilute urea solution that is suitable e.g. for DEF.
Claims21
A process of preparing a concentrated urea-containing liquid stream, the process comprising:
- subjecting a first urea-containing solution which is a urea solution comprising urea, water, ammonia, and carbamate to a low pressure carbamate decomposition step at a pressure of 1.0 to 10 bara and subsequently at least in part to concentration by water evaporation, the water evaporation giving a concentrated urea-containing liquid stream and a first vapor, wherein the water evaporation is carried out at a pressure below 1.0 bara;
- subjecting the first vapor to condensation thereby forming a first process condensate comprising water, urea, carbamate, and ammonia;
- and
- a) combining the first process condensate with a second urea-containing solution that contains at least 30 wt. % urea to form a mixture, and thereafter desorbing NH3 and CO2 from the mixture to form a dilute urea solution, or
- b) combining the first process condensate with a second urea-containing solution that contains at least 30 wt. % urea to form a mixture and simultaneously desorbing NH3 and CO2 from the mixture to form a dilute urea solution;
- or
- c) desorbing NH3 and CO2 from the first process condensate and subsequently mixing the first process condensate with a second urea-containing solution that contains at least 30 wt. % urea to form a dilute urea solution,
- wherein the dilute urea solution formed in a), b) or c) has a molar ratio of water to urea above 1.0 and/or comprises at least 25 wt. % water.
5 more elements
A plant for the production of urea, comprising:
- a high pressure urea synthesis section;
- a low pressure dissociation unit and an evaporation unit connected such that a first urea solution flows from the high pressure urea synthesis section through the low pressure dissociation unit to the evaporation unit, wherein the low dissociation unit comprises an outlet for a gas stream, wherein the evaporation unit comprises an outlet for a first vapor and an outlet for a concentrated urea-containing liquid stream;
- a first condensation unit connected to receive the first vapor from the evaporation unit;
- a mixing zone and a desorption unit configured to combine a first process condensate from the first condensation unit with a second urea solution and to subject the first process condensate to desorption of NH3 and CO2 before, during, or after said combining.
1 more element
A method of modifying an existing urea plant, the existing plant comprising:
- a high pressure urea synthesis section;
- a low pressure dissociation unit and an evaporation unit connected such that a first urea solution flows from the high pressure urea synthesis section through the low pressure dissociation unit to the evaporation unit, wherein the evaporation unit comprises an outlet for a first vapor and an outlet for a concentrated urea-containing liquid stream;
- a first condensation unit connected to receive the first vapor from the evaporation unit;
- a wastewater treatment section connected to receive a first process condensate from from the first condensation unit;
- wherein the method comprises:
- providing the plant with a liquid flow connection for the first process condensate from the first condensation unit to a mixing zone and a desorption unit, wherein the mixing zone and the desorption unit are configured to combine the first process condensate with a second urea solution and to subject the resulting combined stream to desorption of NH3 and CO2 before, during, or after said combining.
3 more elements
Dependencies are inferred from the claim text.