06-02-2013, 04:21 PM
FOUR STAGE CATALYTIC REACTOR FOR A SULPHURIC ACID PLANT
FOUR STAGE CATALYTIC REACTOR.pdf (Size: 1.28 MB / Downloads: 84)
INTRODUCTION
Abstract:
This report consists of the detailed designing of a four pass catalytic bed reactor for a sulphuric acid plant of capacity 1000 TPD. There are two main processes for manufacturing of sulphuric acid namely the chamber process and the contact process. The pioneer sulphuric acid manufacturing plants, adopted the chamber process but at the beginning of the twentieth century with technological advancements, the contact process gained popularity as the conversion achieved was much higher than that achieved through chamber process. Below is a brief description of the process and its main equipment that is the catalytic converter reactor before we carry out the design calculations.
Contact Process:
Sulphuric acid is commercially manufactured by contact process using vanadium catalysts. Until 1990 there were no plants using the contact process, the more popular process being used was the chamber process. But, up to mid 1920’s there were considerable changes in the contact process technology, equipments and the catalyst being used.
Catalyst:
A commercial sulphur dioxide- converting catalyst consists of 4-9 wt % vanadium pentoxide, V2O5, as the active component, together with alkali metal sulphate promoters. At operating temperatures the active ingredient is a molten salt held in a porous silica pellet. Normally potassium sulphate is used as a promoter but in recent years also caesium sulphate has been used. Caesium sulphate lowers the melting point, which means that the catalyst can be used at lower temperatures. The carrier material is silica in different forms. The lower temperature limit is 410-430 °C for conventional catalysts and 380-390 °C for caesium doped catalysts. The upper temperature limit is 600-650 °C above which, catalytic activity can be lost permanently due to reduction of the internal surface. These catalysts are long lived upto twenty years and are not subject to poisoning except fluorine.