Dynamic Density Control for Dense Medium Process

The density control system automatically adjusts the set density in real time to realize unattended operation. It is mainly applied to two dense medium separation systems: Dense medium separator and Dense medium cyclone. 

1. Intelligent Density Control System for Medium dense separator in a Coal Preparation Plant

1. Replace the Gradiomanometer and Liquid level meter.

2. Increase the magnetic medium meter; upstream, horizontal flow is now a manual knife gate valve to ensure improved efficiency of the pneumatic valve replaced in front to this position, five valves each.

3. Connect the water supply valve and divert the valve to the density control system.

4. The final control goal is stabilizing the setting density of 1.85kg/L.

2. Intelligent density control system for the first stage dense medium cyclone in a coal preparation plant

1. Add a qualification medium pump and a tank; add a Gradiomanometer on the outlet pipeline of the qualification medium pump;

2. Before and after the pump, the valves are connected to the intelligent density control system (wear-resistant valve), and the water supply valve and divert valve are connected to the density control system.

3. Add magnetic medium meter and level meter;

4. Calibrate the Ash monitor on belts 706 and 707 and access the data to the control system;

5. When producing low Ash refined coal, the ash separator data is used as the basis for the system density adjustment parameters. When thermal coal is produced, the ash analyzer data is used as the feedback data of the washing results.

3. Intelligent density control system for the second stage dense medium cyclone in a coal preparation plant

1. Add a qualification medium pump, a tank, and a Gradiomanometer on the qualification medium pump outlet pipeline.

2. Before and after the pump, the valves are connected to the intelligent density control system (wear-resistant valve), and the water supply valve and divert valve are connected to the density control system.

3. Add magnetic medium.

4. The main control target is stabilizing the set density value of 2.00kg/L.

Critical Equipment

1.Online Ash & moisture analyzer

Status:

1) A coal preparation plant has two radioactive source ash monitors placed in two final coal upper bin belt machines, and the data fluctuates wildly.

2) There is no online ash & water monitor on the raw coal belt and no natural coal ash data to guide production.

Solution:

1) The product does not use radioactive sources, no rays are generated when power is cut off, and is safe and reliable.

2) Using the principle of combining X-fluorescence technology and X-ray absorption, the measurement method of reflection and transmission solves the influence of the change of element content in coal and the change of coal thickness and density on the measurement.

3) Real-time detection results are given, which solves the lag problem of traditional mining, production, and transformation.

4) Low maintenance - modular design, simple installation, and low maintenance.

Two new side-line X-ray ash & moisture monitors have been added for use with samplers. Calibrate the ash monitor of the two final coal bunker belt conveyors, access the data to the closed control system, guide the density control, record the online ash measurement data into the system, establish the coal quality information database, and provide data support for coal quality application analysis.

Installation Location: raw coal belt conveyor/ clean coal belt machine

2. Density Meter and Other Equipment

Status：

1) The current age or unreasonable installation of the density meter in the coal preparation plant needs to be more accurate, and the density control is guided by manual measurement.

2) Non-magnetic content meter, used with density meter to avoid virtual density.

3) The pressure sensor is not accurate.

4) The level meter needs to be more accurate.

Solution:

The instrument selects high-precision, good-stability tools, cooperates with the technical transformation of the coal preparation plant, and is installed in strict accordance with the instrument installation requirements. All instrument data is connected to the newly added density control PLC cabinet and real-time online monitoring of each monitoring amount of density control.

Gradiomanometer

Voltage: DC24V

Wiring Mode: Two-wire Type

Density Range: 0-2g/Cm³

Signal Output: 420ma

Measurement Accuracy: 0.001gcm³

Probe Distance: 1m/1.5m

Pressure Sensor

Measuring Range: 0~0.4MPa

Measurement Accuracy: ± 0.15% FS

Temperature Self Compensation

Protection Grade: IP65

Medium Temperature: - 40 ℃~+110 ° C

Ambient Temperature: - 40 ° C~+60 ° C

Magnetic Medium Meter

Measuring Range: 0~1000g

Measurement Accuracy: Indication ± 1%

Resolution: ± 1 Word

Host Output: 4~20mADC

Power Supply: 220V ± 10% AC, 50Hz

Pressure Level Meter

Measuring Range: 5m/0.06MPa

Measurement Accuracy: ± 0.15% FS

Temperature Self Compensation

Protection Grade: IP65

Medium Temperature: 40 ° C~+110 ° C

Ambient Temperature: 40 ° C~+60 ° C