Question { IOCL, 8763 }

what is reboiler?

Answer

Reboilers are heat exchangers typically used to provide
heat to the bottom of industrial distillation columns. They
boil the liquid from the bottom of a distillation column to
generate vapors which are returned to the column to drive
the distillation separation.

Question { Sail, 6331 }

where manning formula used

Answer

for open channel flow, or free-surface flow driven by
gravity.

Question { BARC, 21631 }

why we are not using the unit joule for torque instead of N-m.

Answer

Torque has dimensions of force times distance. Official SI
literature suggests using the unit "Newton meter" (N m)
or "Joule per radian".
The joule, which is the SI unit for energy or work, is
dimensionally equivalent to a N m, but this unit is not
used for torque. Energy and torque are entirely different
concepts, so the practice of using different unit names for
them helps avoid mistakes and misunderstandings. The
dimensional equivalence of these units, of course, is not
simply a coincidence: a torque of 1 N m applied through a
full revolution will require an energy of exactly 2π
joules.