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    Process and apparatus for urea production
    27.
    发明授权
    Process and apparatus for urea production 有权

    公开(公告)号：US11498895B2

    公开(公告)日：2022-11-15

    申请号：US17260834

    申请日：2019-07-02

    申请人： TOYO ENGINEERING CORPORATION

    发明人： Kenji Yoshimoto ,  Keigo Sasaki

    IPC分类号： C07C273/04 ,  B01J3/04 ,  B01J19/00 ,  C07C275/02

    摘要： There is provided a process and an apparatus for urea production in which preheating of raw material ammonia or heating in a medium-pressure decomposition step can be performed at a relatively low pressure while preventing decrease in an overall heat transfer coefficient. A process for urea production includes: a synthesis step of generating a urea synthesis solution; a high-pressure decomposition step of heating the urea synthesis solution to separate a gaseous mixture containing ammonia and carbon dioxide from the urea synthesis solution; a condensation step of condensing the gaseous mixture; a medium-low-pressure steam generation step of reducing a pressure of medium-pressure steam condensate obtained in the high-pressure decomposition step to a medium-low pressure to generate medium-low-pressure steam and medium-low-pressure steam condensate; and one or both of a medium-pressure decomposition step and an ammonia preheating step.

    PREPARATION METHOD FOR REMOVING TRIURET CAUSING TURBIDITY IN UREA WATER
    29.
    发明申请
    PREPARATION METHOD FOR REMOVING TRIURET CAUSING TURBIDITY IN UREA WATER 审中-公开

    公开(公告)号：US20190330143A1

    公开(公告)日：2019-10-31

    申请号：US16344154

    申请日：2017-09-05

    申请人： Soultec Co., Ltd

    发明人： Sang Won Shin

    IPC分类号： C07C273/16 ,  C07C275/02 ,  B01F13/08 ,  B01D61/14

    摘要： The present disclosure relates to a preparation method for removing triuret causing turbidity in a urea solution and to a urea solution prepared using the method, and more particularly, to a preparation method, in which urea is introduced to ultrapure water at 15° C. to 24° C. in a magnetic tank with a size of 1 m3 to 20 m3, and the mixture is stirred by using a magnetic mixer and filtered through a hollow-fiber type ultrafiltration membrane (having a pore size in a range of 0.01 μm to 0.3 μm) such that a 32.5% automotive urea solution has a turbidity of 0.02 NTU to 0.2 NTU, and the triuret causing turbidity in a urea solution and reducing conversion efficiency to NH3 in selective catalytic reduction (SCR) is removed. To achieve the purpose of the present disclosure, there is provided a method of preparing a urea solution by dissolving urea in ultrapure water, wherein the 32.5% automotive urea solution is provided by a preparation method including the steps of: a step of preparing ultrapure water at 15° C. to 24° C.; a step of moving the ultrapure water into a magnetic mixer tank; a step of introducing urea to the ultrapure water contained in the magnetic mixer tank; a step of operating a magnetic mixer to induce vortex effect for mixing and stirring the ultrapure water with urea to prepare a urea solution; and a step of filtering by passing the urea solution including triuret through a hollow-fiber type ultrafiltration filter (U/F) to filtrate 20 L of triuret and impurities per 1,000 L of the urea solution, while maintaining a low temperature of the urea solution resulting from the stirring (S5).