Asphalt Plant Burner Control and Dryer Drum Automation

In an asphalt plant the aggregate is dried and heated in the dryer drum before it meets the bitumen. The burner at the end of the drum is the source of that heat and the place where the plant burns most of its fuel — and most of its operating cost. Burner control is both a safety and an efficiency issue: a burner lit in the wrong sequence is dangerous, and an unstable burner either wastes fuel or fails to heat the aggregate enough.

How do the dryer drum and burner work together?

Cold aggregate enters the drum from the collecting belt. As the drum turns, its flights lift the aggregate through the hot gases of the burner flame; moisture evaporates and the aggregate approaches mix temperature. The hot gases and dust are drawn by the exhaust fan to the baghouse filter. That is why the burner cannot be considered on its own: no draught, no combustion. If the draught balance is wrong, the flame blows back or too much heat leaves through the stack.

Safe ignition sequence

The first task of burner automation is to make sure equipment starts in the right order:

The exhaust fan runs and the damper moves to the suction position.
The drum turns and the fuel line pumps are prepared.
The burner’s own flame safeguard completes its pre-purge and ignition sequence.
If no flame signal is detected, or the flame is lost after ignition, fuel is cut and a fault is raised.

Instead of leaving this sequence to the operator’s memory, the software should enforce it: no burner ignition before the fan runs, no feed belt before the drum turns.

Burner modulation and temperature

During production the quantity and moisture of aggregate entering the drum change. With constant burner output the aggregate temperature fluctuates, so the burner’s air-fuel servo is driven open and closed to adjust output. Aggregate temperature is measured at the drum outlet; overshooting wastes fuel and ages the bitumen, while undershooting causes compaction problems on site.

Fuel line and pumps

A healthy burner depends on its fuel line: the fuel feed pump, the high-pressure pump and the return line work together. If one of the pumps trips on its thermal protection, the burner must also stop safely. Good automation monitors every motor’s thermal fault input separately and shows on screen which equipment the fault started in.

How DKT APlants handles the burner

DKT APlants modulates the burner servo open/close, supervises the flame signal and lets the operator reset burner faults from the screen. The dryer, high-pressure pump and fuel return pump are managed in the same chain. Thanks to the machine priority system the burner cannot ignite before the fan runs; when a fault occurs the faulty equipment turns red, equipment stopped because it depends on it turns orange, and the siren sounds.

Frequently asked questions

Why can’t the burner be started before the exhaust fan?

Combustion gases must be drawn out of the drum. A burner lit without draught can blow back flame and hot gas, which is dangerous for both equipment and operator. The automation therefore does not allow ignition before the fan runs.

Why should aggregate temperature be kept stable?

Overheated aggregate wastes fuel and accelerates bitumen ageing; underheated aggregate causes compaction problems on site. Burner output is adjusted to the material entering the drum to keep the temperature stable.

What should the automation do on a burner fault?

Cut the fuel, show the source of the fault on screen and stop dependent equipment in a safe sequence. After the fault is cleared, reset and re-ignition must follow the same safe sequence.

Do I need to replace my existing burner?

No. The burner and its flame safeguard stay in place; the automation software manages the servo, pump and fan chain through the PLC.

Send us your plant’s IO list

The plant’s input/output list and PLC model are enough. We check compatibility together, set up DKT APlants for your plant and show it running in simulation. WhatsApp: +90 547 909 99 90