A urea synthesis system using liquid carbon dioxide

Abstract

The utility model belongs to a kind of urea synthesis system using liquid carbon dioxide;Including urea synthesis tower, urea synthesis tower is connected with liquid ammonia pipeline and carbon dioxide gas pipeline respectively, the carbon dioxide gas pipeline is connected with the outlet of liquid-phase carbon dioxide delivery pump by liquid-phase carbon dioxide vaporization unit, the inlet of liquid-phase carbon dioxide delivery pump is connected with liquid-phase carbon dioxide delivery pipeline;By directly using liquid carbon dioxide as raw material, and using liquid-phase carbon dioxide delivery pump to pressurize, gasification is carried out after pressurization, to meet the requirement of urea synthesis tower, to save urea synthesis energy consumption, reduce the amount of circulating water and reduce the characteristics of equipment floor area.

Claims

1. A urea synthesis system using liquid carbon dioxide, the urea synthesis system comprising a urea synthesis tower (1), the urea synthesis tower (1) being connected to a liquid ammonia pipeline (2) and a carbon dioxide gas pipeline (3), characterized in that: The carbon dioxide gas pipeline (3) is connected to the outlet of the liquid phase carbon dioxide delivery pump (4) through the liquid phase carbon dioxide vaporization unit, and the inlet of the liquid phase carbon dioxide delivery pump (4) is connected to the liquid phase carbon dioxide delivery pipeline (5).

2. The urea synthesis system using liquid carbon dioxide according to claim 1, characterized in that: A methanol separation tower (6) is provided between the inlet of the liquid phase carbon dioxide transfer pump (4) and the liquid phase carbon dioxide transfer pipeline (5).

3. A urea synthesis system using liquid carbon dioxide according to claim 1 or 2, characterized in that: A passivation and corrosion protection unit is provided between the outlet of the liquid phase carbon dioxide transfer pump (4) and the liquid phase carbon dioxide vaporization unit.

4. A urea synthesis system using liquid carbon dioxide according to claim 3, characterized in that: A dehydrogenation purification tower (7) is provided between the liquid phase carbon dioxide vaporization unit and the carbon dioxide gas pipeline (3).

5. A urea synthesis system using liquid carbon dioxide according to claim 1, characterized in that: The liquid phase carbon dioxide vaporization unit includes at least a circulating water heat exchanger (8), a desorption waste liquid heat exchanger (9), and a steam heat exchanger (10); The outlet of the liquid phase carbon dioxide transfer pump (4) is connected to the carbon dioxide gas pipeline (3) in sequence through the first heat exchange pipe of the circulating water heat exchanger (8), the first heat exchange pipe of the desorption waste liquid heat exchanger (9), and the first heat exchange pipe of the steam heat exchanger (10).

6. A urea synthesis system using liquid carbon dioxide according to claim 5, characterized in that: The inlet of the second heat exchange pipe of the circulating water heat exchanger (8) is connected to the urea system circulating water return pipe (11), and the outlet of the second heat exchange pipe of the circulating water heat exchanger (8) is connected to the urea system circulating water supply pipe (12). The inlet of the second heat exchange pipe of the waste liquid heat exchanger (9) is connected to the waste liquid outlet pipe (13) of the hydrolysis and analysis section in the urea system, and the outlet of the second heat exchange pipe of the waste liquid heat exchanger (9) is connected to the coal grinding section (14) of the gasification system. The inlet of the second heat exchange pipe of the steam heat exchanger (10) is connected to the steam network (15), and the outlet of the second heat exchange pipe of the steam heat exchanger (10) is connected to the medium pressure condensate inlet pipe (16) of the urea system steam section.

7. A urea synthesis system using liquid carbon dioxide according to claim 2, characterized in that: The methanol separation tower (6) includes a liquid carbon dioxide inlet (17) located in the lower part of the methanol separation tower (6), a separation tower gas outlet (18) located at the top of the methanol separation tower (6), the separation tower gas outlet (18) being connected to the inlet of the tower bottom heat exchanger (19) located in the lower part of the methanol separation tower (6) via a pipeline, the outlet of the tower bottom heat exchanger (19) being connected to the first gas-liquid separator (26), the liquid outlet of the first gas-liquid separator (26) being connected to the separation tower reflux port (20) at the top of the methanol separation tower (6), the separation tower liquid outlet at the bottom of the methanol separation tower (6) being connected to the crude methanol storage tank (21), and the liquid carbon dioxide outlet in the middle of the methanol separation tower (6) being connected to the inlet of the liquid carbon dioxide transfer pump (4).

8. A urea synthesis system using liquid carbon dioxide according to claim 3, characterized in that: The passivation and corrosion protection unit includes a liquid oxygen pipeline (22), which is connected to the third end of a tee (24) via a corrosion-resistant medium delivery pump (23). The tee (24) is located between the outlet of the liquid phase carbon dioxide transfer pump (4) and the liquid phase carbon dioxide vaporization unit.

9. A urea synthesis system using liquid carbon dioxide according to claim 4, characterized in that: The dehydrogenation purification tower (7) is provided with a gaseous carbon dioxide inlet (25) in the middle and a material outlet (28) at the bottom. The material outlet (28) is connected to the second gas-liquid separator (27), and the gaseous outlet of the second gas-liquid separator (27) is connected to the carbon dioxide gas pipeline (3).

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