• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    An improved method for the preparation of melamine by the conversion of urea and/or thermal decomposition products thereof. The urea and/or thermal decomposition products are converted to melamine in the presence of a gas mixture containing ammonia and carbon dioxide in a reaction zone containing a fluidized bed of catalytically active material. Melamine is desublimated from the melamine containing gas mixture in a desublimation zone by a dry-capture method leaving a desublimator off-gas mixture of ammonia, carbon dioxide and gaseous impurities. A major portion of this desublimator off-gas mixture is compressed and recirculated to the reaction zone as fluidizing gas for the bed of catalytically active material, without intervening treatment to remove gaseous impurities from the desublimator off-gas.
    公开号:SU1060109A3
    申请号:SU802913806
    申请日:1980-04-29
    公开日:1983-12-07
    发明作者:Ван Хардевельд Рудольф；Йен Йосеф Софи Мари Мореау Доминик；Герард Мари Бернард Брюлс Пиер；Герардус Ван Хинсберг Йоханнес
    申请人:Стамикарбон Б.В. (Фирма)；
    IPC主号:
    专利说明:

    2. A method according to Claim 1, distinguishing between gadi and and the fact that melamine is separated in one or several fluidized beds of melamine particles.
    3. Method pop. 1 and 2; This is due to the fact that the melamine is separated when cooled by water to form a pair.
    4, The method according to claims. I - 3, of which the cooling water is fed in countercurrent to the reaction gases carrying melamine.
    B. The method according to paragraphs. 1-4, characterized in that the partial pressure of ammonia in the fluidized bed of the catalyst is 350-2500 kPa.
    This invention relates to methods for producing melamine, the starting material in the synthesis of pesticides and plastics.
    A method of producing melamine by converting urea and / or its thermal decomposition products at atmospheric pressure in a fluidized bed catalyst is followed, followed by desubliming and separating melamine from the gas mixture by cooling. The waste gas mixture, consisting mainly of ammonia and carbon dioxide, is subjected to washing with liquid urea to remove melamine and then, after heating, is partially used in the composition of the gas for fluidization of Cl3
    The disadvantages of this method are uneconomical, since the washing with liquid urea is carried out at a relatively low temperature and therefore the exhaust gas mixture is cooled before washing, and the possibility of driving the pipelines with urea, which is blown away in the form of droplets, with exhaust gases. .
    The purpose of the invention is to simplify the process.
    This goal is achieved in that according to the method of producing melamine by converting urea and / or its thermal decomposition products in a fluidized bed, a catalyst followed by desublimation and separating melamine from a mixture of gaseous reaction products by cooling 50-90% of the outgoing g mixture after compression to compensate for the pressure loss, use the catalyst as a fluidization gas, and the waste gas mixture to be compressed is heat exchanged with the compressed gas ohm
    Melamine is separated in one or more fluidized beds of melamine particles while indirectly cooled with water to form steam.
    The cooling water is fed in countercurrent to the reaction gases carrying melamine,
    The partial pressure of ammonia in the fluidized bed of the catalyst is 350-2500 kPa.
    If necessary, the gas mixture to be compressed is filtered to remove the dust.
    The process is simplified due to the exclusion of flushing the waste gas with a gas mixture, which reduces the overhead of heat, eliminates clogging of pipelines with the liquid urea carried away.
     The drawing schematically shows the implementation of the method.
    . In reactor 1, urea is sprayed through nebulizers 2 and 3 in the fluidized bed of catalyst particles. This layer is fluidized using a gas mixture fed through pipe 4 to supply fluidizing gas and gas distribution grid 5. In the fluidized bed, the required temperature is maintained using heat exchange pipes C. The reaction gases containing melamine are introduced through cyclone 7 and pipe 8 into the desublimator 9. In this desublator 9, which consists of one or more fluidized layers of melamine particles ,. melamine undergoes desublimation.
    The heat released in this process is removed through the tubes of the heat exchanger 10 and converted into high pressure steam.
    In the lower part of the desublimator 9, solid melamine particles are removed through conduit 11. In the separator 12, the melam-n is separated from the gases. These gases are returned through conduit 13 to desublimator 9. Through conduit 14, after the pressure on valve 15 has decreased, melamine is discharged from the plant.
    The melamine-free exit gas mixture is discharged through
    cyclone 16 and pipeline 17. Part of this waste gas mixture is led through pipe 18, for example, to a urea synthesis plant, an N / O2 separation plant, or to a fertilizer plant. The remaining part is recycled through line 19, compressor 20, line 21 and heat exchanger 22 and is fed to reactor 1.
    Example. 20,000 kg / h of urea and 30,000 kg / h of gaseous NH and COj are introduced into the melamine production reactor operating at a pressure of 900 kPa and 375 ° C.
    The reaction gases containing melamine vapor are introduced into the desublimator 9,
    which also works at a pressure of 900 kPa. In this sublimator is a fluidized bed with mepamine particles. The desublimator discharges 7,000 kg / h of melamine, which is characterized by good fluidity and purity of 99.9%.
    80% of the waste gas mixture, which is practically free of melgmin, is recycled to the melailin production reactor, after compression, in order to compensate for the pressure loss in the reactor, desublimator and heat exchanger. The remaining 20% of the waste gas mixture is fed to the separation.
    权利要求:
    Claims (5)
    [1]
    1. METHOD FOR PRODUCING MELAMINE by the conversion of urea and / or its thermal decomposition products in a fluidized catalyst bed, followed by desublimation and separation of melamine from a mixture of gaseous reaction products by cooling and using an exhaust gas mixture of ammonia and carbon dioxide for fluidization, distinguishing it from which, in order to simplify the process, 50-90% of the exhaust gas. mixture after compression · to compensate for the pressure loss use as a gas fluidization of the catalyst and the exhaust gas ! the mixture to be compressed is heat exchanged with the compressed gas.
    601,090 G ’AS
    [2]
    2. The method according to π. 1, the difference between rain and th is that melamine is separated in one or more fluidized layers of melamine particles.
    [3]
    3. The method according to PP. 1 and 2 due to the fact that melamine is separated by indirect cooling with water to form steam.
    [4]
    4. The method according to PP. 1 to 3, characterized in that the cooling water is supplied countercurrent to the reaction gases carrying melamine.
    [5]
    5. The method according to PP. 1 to 4, characterized in that the partial pressure of ammonia in the fluidized bed of the catalyst is 350-2500 kPa.
    类似技术:
    公开号 | 公开日 | 专利标题
    SU1060109A3|1983-12-07|Process for preparing mealamine
    RU2196767C2|2003-01-20|Method of combined production of ammonia and carbamide, plant for method embodiment, method of modernization of ammonia and carbamide synthesis plants
    EA035936B1|2020-09-03|Urea manufacturing method and urea manufacturing apparatus
    AU592360B2|1990-01-11|Process for the preparation of urea
    SU1064863A3|1983-12-30|Process for producing urea
    CN109890788B|2021-08-20|Integrated process of urea and urea-ammonium nitrate
    CA2779841C|2018-01-02|A urea stripping process for the production of urea
    KR870001143B1|1987-06-11|Process for preparing urea
    US5597454A|1997-01-28|Process for producing urea
    KR101320276B1|2013-10-22|Method for concentrating an aqueous ammonium carbamate stream
    EP0018696B1|1982-09-01|Method for the preparation of melamine
    CN108026033B|2020-11-20|Process for producing urea and apparatus for producing urea
    KR100703547B1|2007-04-03|Process for preparing melamine from urea
    US6649795B2|2003-11-18|Process for decomposing a carbamate aqueous solution coming from the urea recovery section of a urea production plant
    CA2595866C|2014-05-20|Process for the preparation of melamine
    US3232982A|1966-02-01|Urea synthesis
    PL68960B1|1973-02-28|
    RU96102868A|1998-05-10|METHOD OF URANE SYNTHESIS FROM AMMONIA AND CARBON DIOXIDE AND METHOD OF INCREASING UREAD URIDE
    同族专利:
    公开号 | 公开日
    NO154393B|1986-06-02|
    NO801283L|1980-11-04|
    NO154393C|1986-09-10|
    PL223958A1|1981-02-13|
    IN153077B|1984-05-26|
    CS220766B2|1983-04-29|
    NL7903473A|1980-11-05|
    RO79649A|1982-08-17|
    EP0018695B1|1982-09-01|
    ES8101057A1|1980-12-01|
    YU117880A|1983-10-31|
    AT1504T|1982-09-15|
    ZA802417B|1981-04-29|
    JPS55149268A|1980-11-20|
    DE3060795D1|1982-10-28|
    JPS55149267A|1980-11-20|
    EG14499A|1985-03-31|
    BR8002683A|1980-12-16|
    ZA802416B|1981-04-29|
    HU184276B|1984-07-30|
    YU40776B|1986-06-30|
    ES491105A0|1980-12-01|
    EP0018695A1|1980-11-12|
    CA1128515A|1982-07-27|
    US4348520A|1982-09-07|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE1670126A1|1966-08-09|1970-10-29|Basf Ag|Process for cooling the exhaust gases obtained during melamine synthesis|
    DE1670286A1|1967-11-11|1971-01-28|Basf Ag|Process for processing the waste gases produced during melamine synthesis|
    DE1812120C3|1968-12-02|1974-02-28|Basf Ag, 6700 Ludwigshafen|Process for the production of melamine|
    US3700672A|1969-04-15|1972-10-24|Nissan Chemical Ind Ltd|Process for recovering by-product gases at high pressure in melamine production|
    US3723430A|1970-10-28|1973-03-27|Nissan Chemical Ind Ltd|Method for reclamation of melamine waste gas|
    US3895007A|1972-04-28|1975-07-15|Basf Ag|Manufacture of melamine|
    NL178487C|1976-03-26|1986-04-01|Stamicarbon|DEVICE AND METHOD FOR SPRAYING A LIQUID.|
    RO74590A|1977-01-19|1981-08-30|Stamicarbon Bv,Nl|PROCEDURE FOR PREPARING MELAMINE FROM URINE|NL8201479A|1982-04-07|1983-11-01|Stamicarbon|METHOD FOR PREPARING MELAMINE.|
    US4565867A|1984-01-05|1986-01-21|Melamine Chemicals, Inc.|Anhydrous high-pressure melamine synthesis|
    DE3500188C2|1984-01-05|1994-08-18|Melamine Chemicals Inc|Anhydrous high-pressure melamine synthesis|
    CA1220476A|1984-01-05|1987-04-14|David E. Best|Anhydrous high-pressure melamine synthesis|
    JP2684409B2|1988-03-31|1997-12-03|コニカ株式会社|Process for producing aniline substituted with cyano group and / or halogen atom and compound used for the production|
    US5389134A|1994-07-18|1995-02-14|Xerox Corporation|Ink compositions for ink jet printing|
    US20030028020A1|2001-07-27|2003-02-06|Gupta Ram B.|Process for the synthesis of high purity melamine|
    DE102005023042B4|2005-05-06|2007-10-31|Lurgi Ag|Process for the preparation of melamine|
    DE102005023041B4|2005-05-06|2007-10-11|Lurgi Ag|Process for producing melamine with heat recovery|
    EP2050740A1|2007-10-15|2009-04-22|Basf Se|Method for manufacturing melamine|
    DE102008032425B4|2008-07-10|2015-07-30|Air Liquide Global E&C Solutions Germany Gmbh|Process and plant for the production of melamine|
    DE102009052420C5|2009-11-10|2014-05-22|Lurgi Gmbh|Process for the continuous production of melamine|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    NL7903473A|NL7903473A|1979-05-03|1979-05-03|METHOD FOR PREPARING MELAMINE.|
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