| 摘要 |
<p>Vapour phase production of maleic anhydride, from used or residual gases obt. during the prodn of maleic anhydride by oxidation of benzene, a fraction of the treated used gas being recycled to the reaction and the used gas which is not recycled being freed from all unchanged benzene, comprises the following stages: (A) the benzene and a gas contg. O2 is contacted with a V-contg. catalyst; (B) the resulting gaseous mixture is cooled to a temp. sufficient to induce the condensation of maleic anhydride, (C) the condensed maleic anhydride is separated; (D) the uncondensed gaseous reaction medium is washed with water to reduce its temp. to 35-45 degrees C and to obt. an aqs. absorption product with a concn. of maleic anhydride not below 40% and used gases contg. uncharged benzene, sec. oxidation products, steam residual maleic anhydride or maleic acid; (E) the used gases are washed with iced water to reduce the temp to 5-25 degrees C and to extract almost all the sec. water-sol. oxidation products and maleic anhydride and/or maleic acid, and to reduce their water content; (F) the cold used gases are washed with a hydrocarbon oil to extract all the benzene and the used gases, freed from benzene, are released to the atmos; (G) the cooled used gases contg. benzene are recovered.</p> |
