METHOD FOR PRODUCING AND PURIFYING MELAMINE
    5.
    发明公开
    METHOD FOR PRODUCING AND PURIFYING MELAMINE 有权
    VERFAHREN ZUR HERSTELLUNG REINIGUNG VON MELAMIN

    公开(公告)号:EP2457902A1

    公开(公告)日:2012-05-30

    申请号:EP10802514.9

    申请日:2010-07-12

    IPC分类号: C07D251/60 C07D251/62

    CPC分类号: C07D251/60 C07D251/62

    摘要: The invention relates to the technique for producing melamine by converting urea into melamine using a non-catalytic method at high pressure, as a whole, as well as to a stage of removing dissolved gases from an aqueous solution of crude Melamine, and can be used in commercial production of melamine. The method for producing melamine comprises a stage of converting urea into melamine at increased temperature and pressure with the formation of a gas-liquid reaction mixture containing melamine, ammonia, carbon dioxide and impurities, and a melamine separation stage. In order to separate melamine, the gas-liquid reaction mixture is cooled with lowering pressure and contacting with an aqueous medium, resulting in the formation of an aqueous solution of crude melamine and the partial removal of dissolved gases. The melamine solution obtained is allowed to stand in order to decompose a part of impurities, the pressure and the temperature are lowered, and the dissolved gases are removed from the aqueous solution of crude melamine using the proposed method by means of blowing water vapour through this solution with simultaneous ammonia introduction. An alkali metal hydroxide solution is added to the resultant melamine solution and melamine is separated from the solution by crystallization. The technical result which can be produced when using this invention involves increase of melamine purity and ensuring independence of its purity from the process parameters fluctuations. Melamine-formaldehyde resins prepared on the base of melamine produced by the proposed method have a high degree of transparency.

    摘要翻译: 本发明涉及通过使用非催化方法在高压下整体将尿素转化为三聚氰胺以及从粗三聚氰胺的水溶液中除去溶解气体的阶段来生产三聚氰胺的技术,并且可以使用 在三聚氰胺的商业生产中。 生产三聚氰胺的方法包括在形成含有三聚氰胺,氨,二氧化碳和杂质的气液反应混合物和三聚氰胺分离阶段的过程中,在升高的温度和压力下将脲转化成三聚氰胺。 为了分离三聚氰胺,气 - 液反应混合物在降低压力下冷却并与水介质接触,导致形成粗三聚氰胺水溶液并部分除去溶解气体。 使所得的三聚氰胺溶液静置以分解杂质的一部分,降低压力和温度,并且使用所提出的方法通过吹入水蒸气从溶解的三聚氰胺水溶液中除去溶解的气体 溶液同时导入氨。 向所得三聚氰胺溶液中加入碱金属氢氧化物溶液,通过结晶将三聚氰胺与溶液分离。 当使用本发明时可以产生的技术结果涉及提高三聚氰胺纯度并确保其纯度与工艺参数波动的独立性。 通过所提出的方法制备的三聚氰胺基底上制备的三聚氰胺 - 甲醛树脂具有高度的透明度。

    METHOD FOR COOLING A MELAMINE MELT
    7.
    发明公开
    METHOD FOR COOLING A MELAMINE MELT 审中-公开
    VERFAHREN ZURKÜHLUNGEINER MELAMINSCHMELZE

    公开(公告)号:EP2907808A1

    公开(公告)日:2015-08-19

    申请号:EP13845206.5

    申请日:2013-09-09

    IPC分类号: C07D251/60

    CPC分类号: C07D251/60 C07D251/54

    摘要: The invention relates to methods for cooling a melamine melt using water and aqueous solutions. The invention can be used in industrial production of melamine. The method for cooling a melamine melt involves cooling a melamine melt with water to temperature of 130-230°C in a cooling zone, with evaporation of water and formation of solid melamine-water vapour gaseous suspension. Melamine is removed from the cooling zone in form of solid melamine-water vapour gaseous suspension. Before removal from the cooling zone, nitrogen, air or a mixture thereof can be added to the formed solid melamine-water vapour gaseous suspension. The technical result which can be achieved using the invention is lowering degree of hydrolysis of melamine when cooling melamine melt with water as well as a simplification of the process.

    摘要翻译: 本发明涉及使用水和水溶液冷却三聚氰胺熔体的方法。 本发明可用于工业生产三聚氰胺。 用于冷却三聚氰胺熔体的方法包括在冷却区中用水将三聚氰胺熔体冷却至130-230℃,蒸发水并形成固体三聚氰胺 - 水蒸汽气态悬浮液。 三聚氰胺以固体三聚氰胺 - 水蒸汽气态悬浮液的形式从冷却区中除去。 在从冷却区中取出之前,可将氮气,空气或其混合物加入到形成的固体三聚氰胺 - 水蒸汽气态悬浮液中。 使用本发明可以实现的技术结果是在用水冷却三聚氰胺熔体时降低三聚氰胺的水解度以及简化工艺。