Question

(Design of Absorption Tower)

a mixture of gas containing 80.3 mole % Hydrogen peroxide (H2O2) and 9.5 mole % Methanol(CH3OH) is to be separated. The absorption process is applied to separate the components. The separation is carried out by using acetone (CH3COCH3) as a solvent. The H2O2 - CH3OH mixture is subjected to enter the absorption tower from the bottom of the column with a flow rate 7900 m3/h, at 286K and 1 atm. Acetone enters the column from the top with a flow rate of 8021 kg/h and at 286 K. 86 % of methanol is supposed to be recovered. And it is suggested that the gas stream should not exceed a permissible pressure drop of 0.00025 N/mm2.
note: Relevant Design data and conditions should be assumed and proper referencing should be provided.
Design an Absorption Tower by evaluating the following parameters.
(i) Number of ideal stages;
(ii) Flow Parameter;
(iii) Tower diameter ;
(iv) Mass flow rate of liquid ;
(v) Height Equivalent Transfer Plate (HETP)
(vi) Interfacial area of packing per unit volume;
(vii) Scaled sketch of packed bed absorption tower with label;

Answer 1

To design an absorption tower to separate a mixture of H2O2 and CH3OH using acetone as a solvent, critical parameters such as the number of stages, flow parameters, tower diameter, mass flow rate, HETP, and interfacial area of packing must be calculated using established correlations and equations based on mass transfer principles.

Step-by-step explanation:

The design of an absorption tower involves several parameters and calculations which are critical for efficient separation of components from a gas mixture. Since absorbers are designed using principles of mass transfer, one needs to consider factors like the number of ideal stages, flow parameters, tower diameter, mass flow rate of liquid, Height Equivalent to a Theoretical Plate (HETP), and interfacial area of packing per unit volume. In this case, the gas mixture contains hydrogen peroxide (H2O2) and methanol (CH3OH), and acetone (CH3COCH3) is used as a solvent. To design an absorption tower for this mixture, one would start by using established correlations and calculations to determine these parameters. The number of stages can be calculated through the use of equilibrium curves or the Kremser equation, while flow parameters could involve considerations such as the L/G ratio (liquid to gas flow rate). The tower diameter is influenced by the allowable pressure drop and the mass flow rates of the gas and liquid. For HETP, packed tower design correlations such as the Onda correlation could be used. Interfacial area of packing could be based on the specific type of packing used in the column, for example, Raschig rings or structured packing.