Heating and cooling is usually out in heat exchangers, where heat is transferred from hot fluid to the cold one. That means the driving force of heat transfer is the temperature difference of the two fluids. When heating any fluids to higher temperature is required, the only method to provide that heat is by heating with direct flame "combustion" at high temperature in an equipment called "FURNACE". Furnace in oil-refineries are considered to be one of the most important equipment to generate the thermal energy used in many process such as atmospheric and vacuum distillation, and in process of thermal cracking and gas processing.