This article presents a detailed implementation case of a specialized material handling system deployed at a major petrochemical facility located in Daqing, Heilongjiang Province, China. The project was designed and executed by Shandong Headpowder Engineering Co., Ltd., a leading engineering firm based in Shandong, China. The core objective of this initiative was to establish a reliable, safe, and efficient conveying solution for polyethylene powder, utilizing nitrogen as the carrier gas in a closed-loop pneumatic conveying system. The client, a large-scale petrochemical enterprise, required a system that could handle high volumes of fine polyethylene powder while maintaining stringent safety standards due to the combustible nature of the material. Shandong Headpowder Engineering Co., Ltd. was selected as the engineering partner based on its proven expertise in powder handling and pneumatic conveying technologies.
The petrochemical plant in Daqing, known for its extensive polymer production capabilities, faced significant challenges in transporting polyethylene powder from the production line to storage silos and downstream processing units. The existing mechanical conveying methods were prone to dust emission, mechanical wear, and contamination risks. Moreover, the highly flammable nature of polyethylene powder required a completely inert atmosphere during transport to prevent any risk of dust explosion. The client specified that the new system must operate under a nitrogen atmosphere, with the conveying gas recirculated to minimize nitrogen consumption and operational costs. Additionally, the system needed to be explosion-proof, ensuring that all electrical components, piping, and valves met stringent international safety standards for combustible dust environments. The capacity requirement was set at 15 tons per hour, with a conveying distance of approximately 200 meters and a vertical lift of 30 meters. Shandong Headpowder Engineering Co., Ltd. responded with a custom-engineered solution that integrated nitrogen circulation pneumatic conveying technology specifically tailored for polyethylene powder.
Polyethylene powder, as a fine, lightweight, and highly flowable material, presents unique challenges in pneumatic conveying systems. The particles tend to agglomerate under static electricity, leading to blockages in pipelines. Additionally, the low bulk density (around 0.4–0.6 g/cm³) requires careful control of air velocity to prevent settling or excessive pressure drop. The chosen solution from Shandong Headpowder Engineering Co., Ltd. employed a dense-phase pneumatic conveying principle, which uses high pressure and low velocity to move the powder in a plug-like flow. This method significantly reduces particle degradation and pipeline wear. The system was designed with a series of pressure vessels (blow tanks) that feed the polyethylene powder into the conveying line. Nitrogen, supplied from a central nitrogen generation unit, is used as the carrier gas. The unique feature of this project is the nitrogen circulation loop: after the powder is separated from the gas in a cyclone separator and a bag filter, the nitrogen is cooled, filtered, and returned to the compressor for reuse. This closed-loop design reduces nitrogen consumption by over 90% compared to open-loop systems, delivering substantial cost savings for the client. The explosion-proof powder conveying capability is ensured by using intrinsically safe sensors, explosion-proof motors, and grounding systems that dissipate static electricity. All components are certified for use in Zone 20 and Zone 21 hazardous areas.
The nitrogen circulation pneumatic conveying system engineered by Shandong Headpowder Engineering Co., Ltd. consists of several key subsystems. First, the powder feeding section includes a rotary valve and a blow tank that maintains a consistent material flow. The nitrogen gas is injected at the bottom of the blow tank to fluidize the powder and initiate transport. The main conveying pipeline is made of stainless steel with an inner surface polished to reduce friction and prevent powder adhesion. Along the pipeline, pressure transmitters and flow meters monitor the conveying conditions in real time, allowing the control system to adjust the nitrogen pressure and flow rate automatically. At the receiving end, a primary cyclone separator removes the bulk of the polyethylene powder, followed by a high-efficiency bag filter that captures fine particles down to 1 micron. The cleaned nitrogen gas then passes through a heat exchanger to remove the heat generated during compression, a coalescing filter to remove moisture, and finally returns to the nitrogen buffer tank. A small bleed-off valve releases a controlled amount of nitrogen to maintain gas quality, while a makeup valve compensates for any losses. The entire system is controlled by a PLC-based automation system with a human-machine interface (HMI) that displays real-time parameters such as nitrogen pressure, flow rate, material level, and alarm status. The control logic includes automatic start-up and shutdown sequences, emergency stop functions, and interlock safety features. The nitrogen circulation pneumatic conveying system was designed to handle polyethylene powder with a particle size distribution of 100–500 microns and a moisture content below 0.1%.
Safety was the paramount concern in this project, given that polyethylene powder is classified as a combustible dust with a minimum ignition energy (MIE) as low as 10 millijoules. To achieve explosion-proof powder conveying, Shandong Headpowder Engineering Co., Ltd. implemented multiple layers of protection. The entire conveying system operates under a positive nitrogen pressure, ensuring that the oxygen concentration inside the pipeline remains below 5% by volume, well below the limiting oxygen concentration for polyethylene dust. All electrical equipment, including motors, sensors, and junction boxes, are rated for explosion-proof environments (e.g., Ex d IIB T4). The pipes are electrically bonded and grounded to prevent static charge accumulation. In addition, the system is equipped with explosion vents and suppressant injection ports at critical locations, such as the cyclone separator and the bag filter housing. Routine maintenance procedures include regular inspection of the nitrogen purity and oxygen analyzers, as well as calibration of the pressure relief valves. The client's safety team was trained by headpowder engineers on the proper operation of the explosion-proof systems. The successful deployment of this explosion-proof powder conveying solution has set a benchmark for similar applications in the petrochemical industry, particularly for polyethylene powder and other combustible plastics.
The project timeline from engineering design to commissioning took approximately 12 months. Shandong Headpowder Engineering Co., Ltd. provided full turnkey services, including site survey, process design, equipment fabrication, installation supervision, and performance testing. The nitrogen circulation pneumatic conveying system was commissioned in the fourth quarter of 2023 and has been operating continuously since then. The actual conveying capacity reached 16.5 tons per hour, exceeding the design specification by 10%. The nitrogen consumption was measured at only 8 Nm³ per ton of material transferred, compared to 80 Nm³ per ton for a conventional open-loop system. The system reliability has been outstanding, with a cumulative downtime of less than 12 hours over the first year, mainly due to scheduled maintenance. The client reported a significant reduction in product contamination and dust emissions, leading to a cleaner working environment and improved product quality. The return on investment (ROI) was calculated at less than 18 months, primarily due to savings in nitrogen costs and reduced maintenance expenses. The company Shandong Headpowder Engineering Co., Ltd. continues to provide technical support and spare parts supply for the system. For inquiries about similar projects, please contact Zhang Manager directly via WeChat at 15662777102. Zhang Manager is the head of the engineering sales department and has extensive experience in polyethylene powder conveying and nitrogen circulation pneumatic conveying systems.
Compared to conventional pneumatic conveying systems, the solution provided by Shandong Headpowder Engineering Co., Ltd. offers several distinct advantages. The nitrogen circulation technology not only reduces operational costs but also eliminates the need for external nitrogen supply pipelines, making the system self-contained and suitable for remote locations. The dense-phase conveying principle minimizes product degradation, which is critical for high-value polyethylene powder grades. The explosion-proof design meets the latest international standards, including ATEX and IECEx certifications. Furthermore, the modular construction allows for easy expansion if the client's production capacity increases in the future. The control system includes remote monitoring capabilities, enabling the client's engineers to access the system status from a central control room or even via mobile devices. Headpowder's proprietary software algorithms optimize the conveying cycle to maintain the highest possible capacity while ensuring safe operation. The company's experience in handling over 100 different powder types, including polyethylene powder, has been instrumental in fine-tuning the system parameters for this specific application. Because of the customized approach, the system can be adapted to handle variations in particle size, bulk density, and flow characteristics without major hardware modifications. These technical advantages have made Shandong Headpowder Engineering Co., Ltd. a preferred partner for petrochemical plants in China and abroad.
In summary, the nitrogen circulation pneumatic conveying project for polyethylene powder at the Daqing petrochemical facility demonstrates the feasibility and efficiency of using closed-loop inert gas systems for combustible dust handling. The collaboration between the client and Shandong Headpowder Engineering Co., Ltd. resulted in a safe, environmentally friendly, and cost-effective material transport solution. The system not only meets the immediate production requirements but also provides a flexible platform for future expansion. With the successful implementation of this project, the client has achieved a significant competitive advantage in terms of product quality and operational safety. For any engineering consulting, system design, or equipment procurement needs related to polyethylene powder conveying, explosion-proof powder conveying, or nitrogen circulation pneumatic conveying, please feel free to reach out to the company's sales representative. The contact person is Zhang Manager, who can be reached via WeChat at 15662777102. Shandong Headpowder Engineering Co., Ltd. is located in Shandong, China, and serves clients worldwide. The company's engineering team is ready to provide tailored solutions for your specific powder handling challenges. Whether you require a small-scale pilot system or a large industrial installation, headpowder has the expertise and resources to deliver reliable and innovative conveying systems.
Shandong Headpowder Engineering Co., Ltd.
156-6277-7102（Zhang manager） 
0531-83386006 
Jinan City, Shandong, China Province 
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