[shibani]

In 1979, a chemical plant was set up, and in the designing of the plant, the chemical engineers used a number of unit operations, distillation being the most vital amongst them. The distillation tower is used to distill out a mixture of aliphatic acids. In the distillation column, a partial condenser was used to condense the vapor, and a reboiler was used for heating purposes. The column is of packed bed type. Steam is used as hot fluid in reboiler.
An audit is done after every 10 years to determine the plant efficiency and safety. When such an audit was done in 1989, it
was seen that the steam flow rate had to be increased to maintain the efficiency.
In 1999, it was observed that the steam flow rate had to be further increased.
In 2006, the engineers noticed that the efficiency of the plant had dropped tremendously, and it had become difficult for them to operate the plant at high levels of efficiency.
You are hired by the plant mechanics, and the following data is given to you. From this data, determine the probable problem in the working of the plant, and suggest remedies to fix it.
Year
Top Pressure (Kg/cm2g)
Steam Flow Rate (Kg/hr)
Feed Flow Rate (m3/hr)
Reflux Flow Rate (m3/hr) 1979 1.97 2840 1268 92.55
1989
1.96
2932
1268
92.69 1999 1.95 3067 1268 92.78
2006
1.92
3250
1268
94.13

[eugenedakin]

Thanks for posting a question shibani,

Could you provide your answers (with the calculations) so that one of our many specialists can help you?

Thanks for your help and understanding,

Eugene