Let’s all talk about furnace control
Thread Content
For material heating furnaces, the amount of fuel gas or fuel oil is controlled based on the temperature of the material after heating, and at the same time the speed of the blower is also regulated. Let’s discuss how stable the automatic operation of the company’s heating furnaces is
What control scheme is used for the furnace on the original poster’s end? Two single-loop controls? Or cascade ratio control?
Small devices are generally used for automatic control at the furnace outlet； However, for large heating furnaces, cascade control of the furnace chamber and furnace outlet is generally used.
Our control scheme here consists of cascade ratio control and dual cross-control, but not everything is set to automatic mode.
Complex control schemes were taken into account during design, but in terms of the actual operation of the devices, most of them cannot be fully automated for various reasons. One of these concepts is that initially, the operators adjusted everything manually, and the results were good. When they tried to switch to automatic mode and found that the outcomes weren’t ideal, they would go back to manual mode; they even stopped trying in the future without having the instrument technicians check for the reasons behind this. In the end, it became a semi-automatic system along with a purely manual one.
I’m not going to tell you that our company specializes in automated control systems for heating furnaces!
When the heating furnace is set to automatic mode, it is difficult to adjust its stability
The opening degree of the blower duct dampers is 70%, so the air volume entering the furnace is high; yet why is the flame in the cylindrical furnace blue and dim? It’s so dark that the furnace tubes cannot be seen
It is probably due to the high content of HS in the fuel. Excessive ventilation, with cold air carrying away heat and thus lowering the flame temperature, may also be a factor
The control schemes for heating furnaces are quite mature; basically, they involve remote manual operation of the temperature at the furnace tube outlet, as well as of the fuel flow and air damper valves. There is oxygen content in the furnace and flue dampers; some of them are connected while others are not. Then, branch balancing is performed for more furnace tubes.