Phthalic anhydride

Type :

Term papers

Pages :

30 pages

Format :

.doc

Published date :

05/22/2009

Category :

Science & technology

Sub category :

Physics & chemistry

Oboulo.com selection criteria

$ 19.95 Add to cart

Summary :

Introduction
Properties
Uses
Selection of raw material
1. Selection of reactor
Method of production
1. Process description
2. Fractional Conversion of o-Xylene into (Yield of) indicated product
3. Major engineering problems
Material balance
1. Material balance around the reactor
2. Material balance around the switch condenser
3. Material balance around the distillation column
Energy balance
1. Energy balance around the reactor
2. Energy balance around the salt cooler
3. Energy balance around the heat exchanger: 2(HE-2)
4. Energy balance around the heat exchanger: 3(HE-3)
5. Energy balance around the switch condenser
6. Energy balance around the distillation column
7. Energy balance around total condenser
Design of tubular reactor
1. Shell
2. Design specifications
3. Details of the construction material
4. Reactor specifications
Economic evaluation
Plant location
Plant layout
Conclusion
Bibliography

Abstract

phthalic anhydride is an important aromatic di-carboxylic acid anhydride. It is an ortho-derivative of phthalic acid. The raw materials are air and o-xylene. The o-xylene feed, which may be considered pure and at 0.75 atm, is pumped to 3 atm and then vaporized in a fired heater. Air, which may be assumed to contain only O2 & N2 is compressed to 3atm and heated in a heat exchanger. The hot air and vaporized o-xylene are mixed and sent to a packed bed reactor. Packed bed reactor is multitubular reactor filled with supported V2O5. 100% of o-xylene is reacted in this reactor. In the selectivity data table we observe the fractional conversion of o-xylene into phthalic anhydride and maleic anhydride are 0.7 and 0.1 at 360◦ C respectively. Also, the selectivity for complete combustion reaction is 0.2. Therefore, the reactor is maintained at 355-365◦ C. Also, the reactor is maintained at 3 atm and a contact time within the reactor is about 0.1-0.4 seconds. Since all the three reactions taking place in a reactor are highly exothermic, the temperature is controlled around 355-365◦ C using Molten salt (High Heat Transfer Salt). The reactor effluent, which is at 2 atm enters a complex series of devices known as switch condensers. The feed to switch condensers may be no higher than 180◦C, hence reactor effluent must be cooled. The net result of switch condensers is that all light gases and water leave the top stream of reactor with small amounts of both anhydrides (PAN & MAN), while large amounts of PAN and MAN leave in stream which is feed to distillation column. The stream containing large amounts of PAN is fed to distillation column which results in formation of bottom product of quality 98% PAN.