| 摘要 |
A phthalic anhydride product having a particle configuration made up of a mixture of spheroids, needle-like crystals, and amorphous particles is produced by feeding molten phthalic anhydride at a temperature between 131 DEG and 155 DEG into a spray nozzle in a closed cycle congealing chamber. The molten phthalic anhydride is discharged from the spray nozzle into a co-current or counter-current flow of inert gas at a temperature between -10 DEG and 70 DEG C., in order to congeal the product, which is then removed and transferred to a hopper or other storage means. For nozzle orifices having a diameter from 1 to 4 mm, discharge pressures of between 10 and 300 pounds per square inch are employed. In an especially preferred embodiment, the needle-like crystalline configurations are disjoined from the spheroids, thereby increasing the bulk density of the product, which in all embodiments exhibits the combination of superior flowability and more rapid dissolution, when compared with prior art products.
|
