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Atekon Technology Co., Ltd.

Case Study on the Coal Preparation Plant Expansion and Upgrade Project of Shanxi Jin Haiyang Energy Co., Ltd. under China National Coal Group

Release date:

2020-03-27

The purpose of coal preparation is to mechanically remove harmful impurities from raw coal, producing marketable coal that meets stringent quality standards and satisfies the diverse industrial needs for coal quality. In recent years, China's coal preparation industry has experienced rapid growth, with an increasing number of coal preparation plants and accelerating advancements in coal preparation technologies. However, numerous challenges still remain. Meanwhile, the continuous development of cutting-edge technologies—such as computer technology, automated control systems, distributed control systems, and PLCs—has laid a solid foundation for the automation of coal preparation processes.

The purpose of coal preparation is to mechanically remove harmful substances from raw coal, producing marketable coal that meets quality standards and satisfies the diverse industrial needs for coal. In recent years, China's coal preparation industry has experienced rapid growth, with an increasing number of coal preparation plants and accelerating advancements in coal preparation technology. However, numerous challenges still remain. Meanwhile, the continuous development of advanced technologies—such as computer technology, automated control systems, distributed control systems, and PLCs—has laid a solid foundation for the automation of coal preparation processes.

The project is located within the Jin Haiyang Industrial Park of Zhongmei Jin Group, in Beizhouzhuang Town, Shanyin County, Shuozhou City, northern Shanxi Province. The project involves a coal preparation plant with a raw coal processing capacity of 12 million tons per year, utilizing a combined process flow that integrates heavy-medium hydrocyclones and pressure filtration technologies.

The project utilizes the AOTEC Technology NA400 series programmable controller as its core. On one hand, the host computer platform communicates with the PLC via Ethernet, receiving control commands from operators to manage the start/stop operations of all plant equipment and adjust process parameters accordingly. On the other hand, through Ethernet, various product metrics and process parameters generated during production can be transmitted to the dispatch room, enabling the entire mine to centrally coordinate human and material resources, thereby ensuring safe and efficient production.

 

System Configuration and Instructions

This system comprises a power distribution system, a PLC control system, a host computer monitoring system, and on-site equipment systems, among others.

The system block diagram is shown as follows.

　　

1. Power Distribution System

Provide power supply to various equipment such as PLC cabinets, conveyor belts, scraper conveyors, pumps, and sensors.

The distribution cabinet is shown as follows:

 

2. PLC Control System

The PLC control system enables real-time acquisition of density, pressure, and button inputs from the washing and sorting site, as well as provides immediate control over on-site equipment. The PLC stations for the raw coal system, primary washing system, thickening system, filter press system, and other auxiliary production systems form the workshop-level equipment network, which utilizes PROFIBUS bus technology—the most widely adopted solution in today’s industrial applications. Additionally, the coal preparation plant leverages Nanjing Aoto’s state-of-the-art NA-400 series control system and industrial Ethernet as its core hardware platform for automation.

The plant-wide integrated control (including closed-loop) system is equipped with the following PLC stations:

(1) Raw Coal Heavy-medium Separation Control System PLC Station >>>

Located in the main plant's distribution room, this system serves as the central PLC cabinet for DP No. 0 and the sub-PLC cabinets for DP Nos. 1 and 2. It primarily monitors equipment within the main plant—including the raw coal grading screen, heavy-medium shallow槽, de-metallizing screen, magnetic separator, lump refined coal centrifuge, medium-concentrating pumps, dilute-medium pumps—as well as belt conveyors and scraper conveyors. Additionally, it detects relevant signals and manages the diversion process, enabling automatic water replenishment and control for five diversion boxes and 13 automatic regulating valves.

(2) Coal Slurry Dense Medium System PLC Station >>>

Located in the main plant's distribution room, this is the PLC cabinet for the No. 3 DP substation, primarily controlling the sorting equipment that processes raw coal smaller than 13 mm.

(3) Hydrocyclone Separation System PLC Station >>>

Located in the main plant's distribution room, this is the PLC cabinet for the No. 4 DP substation, primarily controlling the sorting equipment that processes fine coal particles smaller than 0.5 mm.

(4) Raw Coal Preparation System PLC Station >>>

Located in the distribution room of the raw coal workshop, within the PLC cabinets for DP substations No. 5 and No. 6, it primarily monitors 13 pieces of equipment—including coal feeders, belt conveyors, scraper conveyors, sewage pumps, magnetic separators for belt conveyors, and grading screens—and performs related signal detection.

(5) Concentration and Tail Coal Filter Press System PLC Station >>>

Located in the distribution room of the filter press workshop, it primarily monitors the tail coal filtration system as well as the associated pumps, belts, and scrapers.

(6) Low-Quality Coal and Gangue Storage & Transportation System PLC Station >>>

Set up a distribution room on top of the low-quality coal storage facility, dedicated to the No. 7 DP substation's PLC cabinet. It will primarily control and monitor equipment such as conveyor belts.

(7) Fine Coal and Lump Coal Storage & Transportation System PLC Station >>>

Set up the distribution room on top of the raw coal bunker. It will house the PLC cabinet for the No. 8 DP substation, primarily responsible for controlling and monitoring equipment such as conveyor belts.

(8) Air Compressor Room PLC Station >>>

Located in the air compressor room's distribution room, inside the PLC cabinets for DP substations No. 9 and No. 10, it primarily controls the low-voltage fans and monitors bearing temperatures.

The aforementioned PLC master station, upper-level monitoring system computer monitoring and management station, and data acquisition station are all connected via Ethernet or fiber-optic communication, forming the control-layer network. Meanwhile, the field layer utilizes the PROFI-BUS bus system, which consists of transmission technology, communication protocol standards, general industry rules, and specialized industry guidelines.

The project utilizes a redundant PLC—CPU401-0501 from Nanda Aotuo's high-performance NA400 programmable controller—as the centralized controller for the entire plant. The system incorporates numerous E3 devices and variable-frequency drives equipped with Devicenet communication interfaces, connected via the CMM401-0106 communication module from Nanda Aotuo's NA400 series for networked control. Additionally, protection functions for various conveyor belts—such as rope pull, belt misalignment, stall, and blockage—are monitored through the Dupline bus. These signals are collected using the CMM401-0411 serial communication module from Nanda Aotuo's NA400 series, which communicates directly with the system's master station to ensure real-time acquisition of on-site protection data, significantly enhancing both system reliability and operational safety.

 

3. Host Computer Monitoring System

The host computers consist of one engineer station and three operator stations. GE’s IFIX configuration software is selected, and industrial Ethernet is used to enable communication between the field controllers and the four host computers, facilitating system configuration.

 

Through the automated centralized control system, it is not only possible to monitor the sub-control systems from the central control room, but also to use software for system monitoring, debugging, and programming. This reduces equipment maintenance and repair workload, easing the burden on operational staff.

Since the system was put into operation, the equipment has been running smoothly, and the entire system has experienced no failures whatsoever. It has received unanimous praise from the leaders and operational staff at the coal preparation center.

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