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    Plant for urea production involving a carbon dioxide stripping step
    72.
    发明授权
    Plant for urea production involving a carbon dioxide stripping step 失效
    涉及二氧化碳汽提步骤的尿素生产设备

    公开(公告)号：US5681537A

    公开(公告)日：1997-10-28

    申请号：US483845

    申请日：1995-06-07

    Applicant: Giorgio Pagani

    Inventor： Giorgio Pagani

    IPC: B01J12/02 ,  C07C273/04 ,  B01J8/04

    CPC classification number: C07C273/04 ,  Y02P20/582

    Abstract: An improved process for urea production as well as a method of retrofitting a pre-existing urea plant based on the Stamicarbon process are disclosed. According to the invention, a high-yield reactor with partial removal of the reaction heat and a urea recovery section of the solution leaving the high-yield reactor, are added to the pre-existing urea plant unreacted ammonia and carbon dioxide vapors as well as a carbamate solution obtained in the urea recovery section are recycled to the pre-existing reactor.

    Abstract translation: 公开了一种用于尿素生产的改进方法以及基于Stamicarbon方法改造预先存在的尿素装置的方法。 根据本发明，将具有部分去除反应热的高产率反应器和离开高收率反应器的溶液的尿素回收部分加入到预先存在的尿素装置中，未反应的氨和二氧化碳蒸气以及 在尿素回收段中获得的氨基甲酸酯溶液被再循环到预先存在的反应器中。

    Process for producing urea
    73.
    发明授权
    Process for producing urea 失效
    生产尿素的方法

    公开(公告)号：US5597454A

    公开(公告)日：1997-01-28

    申请号：US418089

    申请日：1995-04-06

    Applicant: Jing M. Lee

    Inventor： Jing M. Lee

    IPC: B01D3/34 ,  B01D3/38 ,  C07C273/04 ,  B01D3/00 ,  C07C273/16

    CPC classification number: B01D3/34 ,  B01D3/38 ,  C07C273/04 ,  Y02P20/124 ,  Y02P20/57

    Abstract: A urea production process combining lower pressure urea concentration and carbamate recovery steps into a single non-vacuum operation. Following high pressure stripping wherein a bulk of unreacted carbamate is recovered from the reaction effluent, remaining carbamate is stripped by heated air at atmospheric pressure wherein urea is concurrently concentrated without the use of vacuum evaporators. Weak carbamate solution subsequently formed is stripped of water (and residual urea is hydrolyzed) using air and steam at a medium pressure single tower hydrolyzer/stripper to obtain a concentrated carbamate stream suitable for recycle to the reactor. The process employs heat integration for enhanced energy efficiency and produces a good quality aqueous condensate suitable for direct use as boiler feed water. Thus the aqueous condensate produced requires no additional cooling and ammonia treatment. The process employs simplified and reduced process unit operation to eliminate equipment for cost reduction.

    Abstract translation: 将低压尿素浓度和氨基甲酸酯回收步骤组合成单一非真空操作的尿素生产方法。 在高压汽提之后，从反应流出物中回收大量未反应的氨基甲酸酯，剩余的氨基甲酸酯在大气压下被加热的空气汽提，其中尿素同时浓缩而不使用真空蒸发器。 使用空气和蒸汽在中压单塔水解器/汽提器上将随后形成的弱氨基甲酸酯溶液除去水（和残留的尿素水解），得到适于再循环至反应器的浓氨基甲酸酯流。 该方法采用热集成来提高能源效率，并产生适合直接用作锅炉给水的优质水凝胶。 因此，产生的水凝胶不需要额外的冷却和氨处理。 该过程采用简化和简化的过程单元操作，以消除设备降低成本。

    Apparatus for increasing the yield and the production potential of urea reactors
    74.
    发明授权
    Apparatus for increasing the yield and the production potential of urea reactors 失效
    用于提高尿素反应器的产量和生产潜力的装置

    公开(公告)号：US5304353A

    公开(公告)日：1994-04-19

    申请号：US821428

    申请日：1992-01-15

    Applicant: Mario Dente ,  Sergio Bozzano

    Inventor： Mario Dente ,  Sergio Bozzano

    IPC: B01D3/20 ,  B01D3/22 ,  B01D53/22 ,  B01J10/00 ,  B01J19/00 ,  B01J19/24 ,  C07C273/04 ,  B01J8/04 ,  B01D3/14 ,  C07C273/00

    CPC classification number: C07C273/04 ,  B01D3/20 ,  B01D3/22 ,  B01J10/00 ,  B01J19/006 ,  B01J19/24 ,  B01J2219/0077 ,  B01J2219/00777

    Abstract: Urea is formed by the synthesis of ammonia with carbon dioxide at high pressure and temperature in an internal space of reactors through which flow a liquid phase cocurrently with a gas phase. The reactors are divided into compartments to avoid excessive mixing of the entire liquid phase and to allow the intermittent redistribution of the gas in bubbles of a suitable size for increasing the exchange of heat and matter between the two phases. At each passage from one compartment to the next, the liquid phase and the gas phase are made to flow on separate routes and are distributed in each compartment with a continuous, permanent, and even flow.

    Abstract translation: 通过在反应器的内部空间中在高压和高温下合成氨与二氧化碳形成尿素，通过该反应器将液相与气相并流流动。 反应器被分成隔室以避免整个液相的过度混合，并允许气体间断地重新分配为合适尺寸的气泡，以增加两相之间的热量和物质的交换。 在从一个隔室到另一个隔室的每个通道处，使液相和气相在不同的路线上流动，并以连续的，永久的和均匀的流量分布在每个隔室中。

    Process for the modernization of existing urea plants and a modernized urea plant
    75.
    发明授权
    Process for the modernization of existing urea plants and a modernized urea plant 失效
    现有的尿素植物和现代化尿素植物现代化的方法

    公开(公告)号：US5176800A

    公开(公告)日：1993-01-05

    申请号：US634410

    申请日：1990-12-27

    Applicant: Umberto Zardi ,  Giorgio Pagani

    Inventor： Umberto Zardi ,  Giorgio Pagani

    IPC: C07C273/04

    CPC classification number: C07C273/04 ,  Y02P20/142

    Abstract: A process to modernize existing urea plants which use a stripping with carbon dioxide, and to increase urea yields and flexibility under overload conditions while at the same time reducing energy consumption, corrosion phenomena and possible risks of explosive mixtures. The plant includes: a passivation stage with the introduction of an oxidizing agent and reduction of the air fed to the system; a medium pressure distillation stage of the products leaving the stripping section, and a condensation of the products of the distillation, effected in a pre-evaporation phase to concentrate at low pressure the urea solution.The modernized plant, includes at the start at least a reactor, a scrubber, a condenser, a stripper and the evaporators, includes also a passivation section, a medium pressure distillation section, and a distillation section with double-effect technique.

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