Oil heating furnace control based on calculation of the heat balance

Abstract

The oil heating furnace is a crucial component of the oil treatment unit and can utilize associated petroleum gas as fuel. However, gases of varying compositions require different amounts of air for complete combustion.  

The required air volume and the heat of combustion can vary significantly depending on the chemical composition of the gas. Currently, the furnace control is carried out using a PID controller to maintain a target outlet temperature for the product. The fuel gas pressure in the supply line is kept constant, and the amount of air is set using pre-calculated coefficients, which are occsionally adjusted based on oxygen measurements in the flue gases. In practice, the air-to-gas ratio is often manually adjusted based on the flame color, while the automatic air pressure control sys-tem is either not utilized or operates inefficiently. PID coefficient settings is infrequently per-formed, leading to inefficient combustion, particularly when burning richer associated petroleum gas. This results in the release of unburned fuel components into the atmosphere and can cause overheating of the oil product.  

In this study, the authors propose furnace control algorithm based on dynamic calculations of heat and mass balances. The primary goals of this algorithm are to maintain the desired outlet temperature of the oil and to ensure the efficient combustion of associated petroleum gas.