Continuous freezing condenser for phthalic anhydride. [Patented]
The increasing outputs of plastics and polymer materials necessitate correspondingly larger outputs of various organic monomers. Phthalic anhydride is one of the source products for organic synthesis. Phthalic anhydride is made in the coking industry by the catalytic vapor-phase oxidation of naphthalene. The product is difficult to isolate from the reaction mixture leaving the static-bed catalytic reactors, since the volume of gases and vapors to be cooled is very large and the phthalic anhydride concentration in the mixture is very low. Continuous freezing condensers have been developed, in which the gas stream is cooled by counterflow contact with a stream of solid granular material on which the phthalic anhydride is condensed. One serious drawback is the need to expend large amounts of heat to remelt the phthalic anhydride crystals. The low strength of the granulated solid substrate leads to dust formation in operation, and the dust contaminates the product. We have developed a condenser in which the freezing and remelting stages take place on metal balls in the same unit and the heat is derived from the incoming reaction mixture. Accordingly, units of large capacity can be constructed giving a higher product yield and lowering the heat consumption in the remelting stage.
- OSTI ID:
- 6289978
- Journal Information:
- Coke Chem. USSR (Engl. Transl.); (United States), Vol. 7; Other Information: Translated from Koks Khim.; No. 7, 37-38(1981)
- Country of Publication:
- United States
- Language:
- English
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Process for the production of phthalic anhydride
Phthalic anhydride production is a catalytic process