Question

a) If steam is such a great way to move energy around, for what food process operations do we need electricity?

b) Why do we not use electricity for ALL heating related unit operations?

Answer 1

Theory: Steam is basically governed by the temeprature of stream and energy is governed by the voltage difference across the circuit.

Solution: Steam has a great way to move enrgy. It is rightly said but it has a high temeprature. At atmospheric pressure, steam has 100 DegC of temeprature which if remains in contact with human body for very long time, it can create some health issues to the person. So in small uses like making tea or induction cooker we use the electricity. we do not use steam for most of the cases due to vulnerability from high temeprature. Electricity is more safe option to use for a small application process.

Now for bigger applications, if we use electrical heating then we will require very high voltage. In commerical applications all the materials for pipe and vessels are conductive enough and if we use the electrical energy (required at very high voltage to fulfiil the demand), current can paas through these ipe line or valves which is very dangerous. At these places steam heating is economical. Since it is a commercial process. People can well insulate(actually afford to do so) the sytem thermally so that heat losses are minimum and all process requirments are needed.