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    7.
    发明专利
    未知

    公开(公告)号：PT86069A

    公开(公告)日：1988-12-15

    申请号：PT8606987

    申请日：1987-11-03

    Applicant: STAMICARBON

    Inventor： JONCKERS KEES ,  BURKS HENK CHRISTIAAN

    IPC: C07C67/00 ,  C07C239/00 ,  C07C273/04 ,  C07C127/00

    Abstract: Process for preparing urea in which, - at a pressure of 125-350 bar and the corresponding temperature, a urea synthesis solution containing carbamate is formed from carbon dioxide and an excess of ammonia, - in a first decomposition step part of the carbamate is decomposed, with supply of heat and in countercurrent contact with a stripping gas, and the resulting gas phase is in part condensed in a first con-densation zone, - in at least two further decomposition steps a further part of the carbamate still present is decomposed and the gas mixture formed is separated off, in the first of the further decomposition steps a pressure of 4-40 bar being maintained, - the remaining urea-containing solution is processed by evaporation to form a concentrated urea solution, the heat required for evaporation being obtained at least in part by condensation of the gas mixture obtained in the first of the further decomposition steps. The gas mixture used in the first evaporation step is formed by the gas phase resulting from the heat exchange between the part of the stripped urea synthesis solution expanded to a pressure of 4-40 bar and the condensing gas mixture in the first condensation zone.

    8.
    发明专利
    未知

    公开(公告)号：BR8705824A

    公开(公告)日：1988-06-28

    申请号：BR8705824

    申请日：1987-10-30

    Applicant: STAMICARBON

    Inventor： JONCKERS KEES ,  BURKS HENK CHRISTIAAN

    IPC: B01D1/22 ,  B01D1/06 ,  C07C67/00 ,  C07C239/00 ,  C07C273/04 ,  C07C273/16 ,  F28F13/04 ,  C07C126/02

    Abstract: Process for concentrating a urea solution passing as a film along the inside of the tubes (2) of a vertical tube bundle the heat required being substantially generated by condensation of a gas mixture in a area provided around the bundle of tubes, the gas mixture being supplied to the area near one end of the tube bundle (2) and the urea solution to the other end of the tube bundle (2), and being passed substantially upwards through the heating area and it is ensured that the gas mixtureor condensate cannot flow back. Installation for carrying out the process wherein the heating area is divided into compartment by means of horizontal baffles (3) allowing an upwardly directed flow of the gas mixture and the condensate.

    9.
    发明专利
    未知

    公开(公告)号：BR8705820A

    公开(公告)日：1988-06-28

    申请号：BR8705820

    申请日：1987-10-30

    Applicant: STAMICARBON

    Inventor： JONCKERS KEES ,  BURKS HENK CHRISTIAAN

    IPC: C07C67/00 ,  C07C239/00 ,  C07C273/04 ,  C07C126/02

    Abstract: Process for preparing urea in which, - at a pressure of 125-350 bar and the corresponding temperature, a urea synthesis solution containing carbamate is formed from carbon dioxide and an excess of ammonia, - in a first decomposition step part of the carbamate is decomposed, with supply of heat and in countercurrent contact with a stripping gas, and the resulting gas phase is in part condensed in a first con-densation zone, - in at least two further decomposition steps a further part of the carbamate still present is decomposed and the gas mixture formed is separated off, in the first of the further decomposition steps a pressure of 4-40 bar being maintained, - the remaining urea-containing solution is processed by evaporation to form a concentrated urea solution, the heat required for evaporation being obtained at least in part by condensation of the gas mixture obtained in the first of the further decomposition steps. The gas mixture used in the first evaporation step is formed by the gas phase resulting from the heat exchange between the part of the stripped urea synthesis solution expanded to a pressure of 4-40 bar and the condensing gas mixture in the first condensation zone.

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