Solve Pain Points in Coal Conveying and Consolidate the Foundation for Power Supply! Recently, the installation, commissioning and full-load material test for the blockage-clearing retrofit of No.4 Raw Coal Bunker for Unit 1 at SDIC Panjiang Power Plant, undertaken by Beijing DaTongLongYuan Energy Technology Co., Ltd., were fully completed on August 21. The complete blockage-clearing system operates stably, successfully resolving long-standing operational pain points such as coal bridging, arching and wall-hanging coal accumulation in raw coal bunkers, and providing robust support for the continuous and reliable operation of the plant’s coal-handling system.

Located in Liupanshui, Guizhou Province, SDIC Panjiang Power Plant is a key domestic power generation base for comprehensive utilization of low-calorific-value coal, undertaking critical power supply tasks for the West-to-East Power Transmission Project and operated by State Development Investment Corporation. The plant burns large proportions of low-calorific-value fuels including coal slime and gangue. These fuels feature high moisture and strong adhesion, frequently causing wall-adhered coal buildup, material bridging and arching, and poor material flow inside raw coal bunkers during operation. Such conditions readily lead to coal supply interruption and feeder feed fluctuation, directly undermining boiler combustion stability and even triggering unit load reduction in severe cases. Conventional manual blockage removal is high-risk confined-space work featuring low dredging efficiency and prominent personal safety hazards, restricting the plant’s long-term safe, efficient production.

On-site photos of coal bunker blockage

Photos of coal blockage inside the coal bunker

To fundamentally tackle stubborn coal-blockage issues, the project team adopted a customized technical solution integrating upper-and-lower scraper blades for gate valves plus air knives, based on on-site coal properties, bunker structure and unit operating conditions, to carry out systematic upgrading and retrofit for raw coal bunkers and coal-fall sections. Leveraging a 7-day unit shutdown window, the project overcame multiple challenges including confined working space, multi-disciplinary cross-construction and tight schedules. The Engineering & Technology Department coordinated construction plans while multi-disciplinary personnel worked in close collaboration. Strict on-site safety control was enforced throughout full-sequence workflows including old-equipment dismantling, equipment positioning, welding and installation, pipeline layout, electrical control wiring, stand-alone commissioning and joint testing to ensure all key milestones were achieved on schedule.

After retrofit, external driving mechanisms drive continuous movement of scraper assemblies of the blockage-clearing device to strip and disturb coal layers adhered to bunker walls in real time. Complementary pneumatic purging by air knives delivers high-pressure airflow to blow off residual sticky coal on bunker walls. The combined actions actively break up bridging and arching of bulk materials. Equipped with an intelligent control system supporting local/remote operation and interconnection with the plant’s DCS system, the solution shifts the former passive “clear-after-blockage” mode to proactive pre-emptive anti-blockage control. It drastically cuts coal-blockage failure rates and reduces high-risk manual bunker-clearing work. Seamlessly compatible with the existing on-site coal-conveyor belt system, it guarantees smooth and uninterrupted coal flow.

Post-retrofit photos

Full-load material test data demonstrate that the retrofitted raw coal bunker delivers smooth, even coal discharge with no wall-hanging coal buildup or bridging blockage. Coal supply continuity is greatly improved. Risks of coal supply interruption and combustion fluctuations stemming from coal-bunker blockage are thoroughly mitigated. Operation-and-maintenance manpower input and overhaul costs are effectively lowered. The test fully validates the adaptability and reliability of the complete blockage-clearing retrofit solution, strongly supporting stable full-load unit power generation and consolidating regional domestic power-supply capacity.

The successful delivery of this coal-bunker blockage-clearing retrofit marks another key practical achievement of DaTongLongYuan in domestic thermal power technical renovation. The project delivered integrated implementation covering technical solution design, equipment manufacturing, on-site construction and commissioning hand-over. It further demonstrates the company’s mature technical expertise and project performance capability in material anti-blockage and blockage-clearing fields, and accumulates valuable practical experience for coal-bunker retrofits under operating conditions of highly sticky, low-calorific-value coal.

Going forward, DaTongLongYuan will further deepen its presence in the domestic thermal power market, focusing on diverse pain points in power plant coal handling systems. By delivering customized technical solutions and high-standard project execution, the company will provide more high-quality technical renovation projects, help domestic power generating enterprises pursue higher efficiency, better quality and safer stable operation, and contribute to the high-quality development of the energy industry.