Systems and methods for integrated ammonia-urea process
AssigneeKellogg Brown & Root LLC
InventorVishnu D. Singh
Life of this patent
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Abstract
Systems and methods for producing urea are provided. A method for producing urea can include exchanging heat from a syngas comprising hydrogen and carbon dioxide to a urea solution comprising urea and ammonium carbamate. The heat transferred can be sufficient to decompose at least a portion of the ammonium carbamate. In one or more embodiments, the syngas can be reacted with liquid ammonia to provide a carbon dioxide lean syngas and an ammonium carbamate solution. The ammonium carbamate solution can be heated to a temperature of about 180° C. or more. At least a portion of the ammonium carbamate in the heated ammonium carbamate solution can be dehydrated to provide the urea solution.
Claims20
A method for producing urea comprising:
- exchanging heat from a syngas comprising hydrogen and carbon dioxide to a urea solution comprising urea and ammonium carbamate, wherein the heat transferred is sufficient to decompose at least a portion of the ammonium carbamate;
- reacting the syngas with liquid ammonia to provide a carbon dioxide lean syngas and an ammonium carbamate solution;
- heating the ammonium carbamate solution to a temperature of about 180° C. or more;
- and
- dehydrating at least a portion of the ammonium carbamate in the heated ammonium carbamate solution to provide the urea solution.
A method for producing urea comprising:
- exchanging heat from a syngas comprising at least 12% mol carbon dioxide to a first solution comprising about 27-31% wt urea, about 20-25% wt ammonium carbamate, about 27-31% wt ammonia, about 0-4% wt CO2, and about 16-20% wt water, wherein the heat transfer is sufficient to decompose at least a portion of the ammonium carbamate;
- reacting the cooled syngas comprising at least 12% mol carbon dioxide with liquid ammonia in the presence of water to provide a second solution comprising about 65-75% wt ammonium carbamate, about 22-25% wt water, and less than about 5% wt ammonia and a syngas comprising at least 20% mol nitrogen, at least 65% mol hydrogen and less than 3% mol carbon dioxide;
- heating the second solution to a temperature of at least 180° C.;
- and
- dehydrating at least a portion of the ammonium carbamate in the heated second solution to provide the first solution.
A system for producing urea comprising:
- one or more ammonium carbamate decomposers adapted to exchange heat from a syngas comprising at least 12% carbon dioxide to a first solution comprising about 27-31% wt urea, about 20-25% wt ammonium carbamate, about 27-31% wt ammonia, about 0-4% wt carbon dioxide, and about 16-20% wt water, wherein the heat transfer is sufficient to decompose at least a portion of the ammonium carbamate;
- one or more carbon dioxide absorbers adapted to react the cooled syngas comprising at least 12% carbon dioxide with liquid ammonia in the presence of water to provide a second solution comprising about 65-75% wt ammonium carbamate, about 22-25% wt water, and less than about 5% wt ammonia and a syngas comprising at least 20% mol nitrogen, at least 65% mol hydrogen and less than 3% mol carbon dioxide;
- one or more heat exchangers adapted to heat the second solution to a temperature of at least 180° C.;
- and
- one or more reactors adapted to dehydrate at least a portion of the ammonium carbamate in the heated solution to provide the first solution.
Dependencies are inferred from the claim text.