There are a couple of other threads on burner control and steam rasing efficiency improvements that may hold some of the answers.
This link is to a good article on burners:
http://www.coen.com/i_html/white_liquidfuel.html
Undoubtedly one of the problems with liquid fuel firing is that havey fuel oil quality can be extremely variable. This means that the conventional approach to fuel heater control is often based on a strategy of frequent sampel anslysis to determine the optimum temperature for fuel heating, excess oygen and flame inspection.

Today, however, modern viscometers can assist in much more efficient heater control because they automatically compensate the heaters for variations in fuel quality.

A message about pollution can be read in the case of the EPA Vs PREPA (Puerto Rico Electric Power Association) where they were required to source a suitable viscometer for their bunker C fuel oil heater control.

Efficient combustion is one part of the equation (and returns significant savings through reducing excess oxygen and avoiding excess soot blowing) and doesn't represent a complete solution, i know, but i can't help with any other aspects. Perhaps some others can.

Incidentally, viscometers can not only help with combustion efficiency but also with blend control whether it is crudes, fuel oils or asphalts (bitumens) and are a key component in many fuel oil blending systems.

JMW
www.ViscoAnalyser.com