Trying Not To Use Energy While Making Energy

Hello,

This post will be on the optimization of energy within an oil refinery.  In many ways, energy optimization is a subset of economic optimization because if you save energy you save money.  However, I feel that it is important to set it aside because it is one area of refineries that has waste in some form (nor is it possible to completely prevent really).

So first things first, what do I mean by energy optimization?  In refineries, it takes energy to heat and cool the products for the distillation process.  Furthermore, there are compressors that require energy to pump the fluids and even light sources that require power amongst other parts of the refinery that require energy.  The optimization comes into play through figuring out our to best layout the refinery to use the least amount of energy as possible.

Energy optimization in refineries starts with heat.  To gain some perspective at the heat differences, some substances are heated to well over 1000 degrees fahrenheit while others are cooled to a good amount under 0 degrees.  As you would expect, the heating and cooling of these substances takes a lot of energy.  Also, for distillation to work, substances have to be heated to their boiling point, then condensed back into their liquid state.  This leads into the waste in energy.  When a heated substance is cooled, there is a waste of energy in the form of heat.  To combat this refineries use heat exchangers.

A heat exchanger allows a heated substance to heat a different substance, thereby using the thermal energy of the first substance.  It is important to note that the heat exchanger does not mix the two substances (that would be counter productive…) but rather only allows heat to be transferred between the two.  Heat exchangers are more efficient when they limit the amount of heat lost to the environment.

Another important area for refineries is that of pumping the fluids from unit to unit.  Compressors are the main energy drain here and are required when pumping a substance from low to high pressure.  This means that the best way to optimize energy in this regard is to lay out the refinery in such a way that limits the need for compressors.  To put it in simpler terms, engineers try to adjust the layout of the refinery to use gravity and pressure in their favor when moving substances from one unit to another.  

Well that’s the basics of energy optimization.  If there is anything not clear in here, I will be happy to answer questions in the comments.  On a side note, my 18th birthday is tomorrow, so I’ll be writing next week a year older (because that’s how age works, best not to question it).

Stephen