EFFECT OF LIQUID FLOW RATE AND GAS FLOW RATE ON A PACKED ABSORPTION TOWER AND REPAIR OF EQUIPMENT

1.0 INTRODUCTION
The removal of one or more selected components from a mixture of gases by absorption into a suitable liquid is the second major operation of chemical engineering that is based on inter phase mass transfer controlled large by rates of diffusion
Gas absorption defined by Perry is a unit operation in which a soluble components of a gas mixture are dissolved in a liquid. The inverse operation is called stripping or description.
In gas absorption a soluble rapour is absorbed from its mixture with an inert gas by means of a liquid in which the solute gas is more or less soluble. The washing of ammonia for a mixture of ammonia and air by means of liquid water is a typical example. The solute is subsequently recovered from the liquid by distillation and the absorbing liquid can be either discarded or reused. An acetone air mixture passed through a gas stream can recover acetone by its dissolving in the gas and allow the air to pass out. In each of the example given only physical process take place with no chemical affect appreciable. However when oxides of nitrogen are absorbed dioxide is absorbed in a solution of sodium hydroxide, a chemical reaction occurs, the nature of which influences the actual rate of absorption
In considering the design of equipment to achieve gas absorption, the main requirement is that gas be brought into intimate contact with the liquid and the effectiveness of the equipment will largely be determined by the success with which it promotes contact between the two phases.