There is no shortcut for BARC, You have to go through details and deep knowledge.
BARC will ask you to select up to 5 favourite subjects ( 3 is mandatory ).

Think and grow in GATE Chemical by A K Verma ( it will help you to remember all formulas, dimensionless numbers, measuring instruments and importance points)     Click here

For Fluid Mechanics, Must read Cengel.         Download

For Heat transfer, Must read Cengel               Download

For Mass Transfer, Must read Cengel and treybal      Download

For Process Dynamics and Control, Must read Coughanowr     Download

For Chemical Reaction Engineering, Must read Levenspiel     Download

For Design and Economics, Must read timmerhous      Download