New burner enables stable coal combustion at ultra-low loads without auxiliary fuel

With the growing integration of renewable energy, thermal power plants face increasing pressure to provide flexible operation and deep peak regulation. However, existing swirl combustion technologies, especially when burning low-volatility or high-ash "faulty coal," struggle to maintain stable combustion below 50% of the rated load without auxiliary support such as oil. This limitation hinders the ability of power units to meet the current requirement of operating at 35%–30% load for deep peak shaving.

A study published in ENGINEERING Energy (formerly Frontiers in Energy) by researchers from Harbin Institute of Technology and partner institutions introduces a novel deep peak regulation burner (DPRB). The authors developed the DPRB to achieve stable combustion at 15%–30% of the boiler’s rated load without auxiliary fuels. The research combines gas-particle flow experiments, industrial trials, and transient numerical simulations to evaluate the burner’s performance.

The DPRB eliminates the central air and bluff body used in conventional designs, instead employing gap-swirled secondary air to entrain straight primary air, forming a controllable recirculation zone (RZ).

The main findings are as follows:

• At full load, the DPRB formed a central recirculation zone (RZ) with a length of 1.5d and a diameter of 0.58d.
• Under low-load conditions (40%–15% rated load), the RZ transitioned into an annular structure with a length of 1.0d and diameters ranging from 0.30d to 0.40d.
• Particle concentration rings were observed in the central region, which helped promote pulverized coal accumulation and enhanced ignition performance.
• During rapid load increases from 20% to 30%, the prototype burner extinguished at a rate of 3%·min⁻¹, whereas the DPRB maintained stable combustion throughout the process.
• Temperature measurements showed that the DPRB’s central region reached 750 °C at 0.65–0.70 m from the outlet, enabling earlier ignition than the prototype burner.

This study demonstrates that the DPRB improves combustion stability and load-adjustment flexibility in boilers firing faulty coal. By enabling stable ultra-low load operation and rapid load response, the technology supports the integration of renewable energy and contributes to the transition of the energy structure.

Journal: ENGINEERING Energy (formerly Frontiers in Energy)

Read the full article for free: https://rdcu.be/eSqhJ

Cite this article: Huang, C., Li, Z., Lu, Y. et al. Gas-particle flow and rapid load-up characteristics of a novel deep peak regulation burner. Front. Energy 19, 738–756 (2025). https://doi.org/10.1007/s11708-025-0994-4