Instance of Jiangsu Pengfei-Malawi 500tpd production line coal metering system
发布日期：2021-07-23 浏览次数：680
1.Project Introduction
The 500t/d production line in Malawi, the general contractor of Jiangsu Pengfei Group, selected our company's kiln head and kiln tail pulverized coal metering system. The kiln tail pulverized coal consumption is 1-5t/h, and it use our standard KXT(M)-I Coriolis pulverized coal metering system. However, the consumption of pulverized coal at the kiln head is only 0.9-1.1t/h. The project design company initially planned to use a bypass valve to simply split the pulverized coal pipeline from the kiln tail to the kiln head for use. However, this plan increased the instability of the air conveying system, and the stability and uniformity of the kiln head pulverized coal consumption cannot be guaranteed. Finally，according to our recommendation, kiln head pulverized coal metering adopts our company’s small and trace coal pulverized coal loss-in-weight weighing scale program.
2.Design Program
The process layout of the kiln head and kiln tail pulverized coal metering of the project is shown in Figure 1. The micro-weight loss-in-weight pulverized coal metering scale and the kiln tail pulverized coal metering system are arranged side by side at the bottom of the pulverized coal silo, and the side of the pulverized coal silo cone has holes. Through the pneumatic gate valve and the transition pipe, it is connected to the self-contained weighing silo of the loss-in-weight pulverized coal metering scale.
The key design points of micro-weight loss-in-weight pulverized coal weighing scale:
（1）A weightless warehouse with a high-precision weighing sensor is used as the metering device, the flow is controlled by a flow stabilizer, and the screw pump completes the pneumatic conveying of pulverized coal.
（2）The system control accuracy reaches ±1%.
（3）When installing, we pay attention to the angle of the slide pipe from the large coal bin to the weighing bin, and install a spray device on the slide pipe to ensure the fast and unobstructed feed from the big bin to the small weighing bin.
（4）Must ensure that the material height of the warehouse is within a reasonable range.
（5）Note that the dust collection air volume of the weighing silo and the top silo of the screw pump should not be too large, the connection of the dust collection pipe must be disconnected, and the angle of the collection pipe must be greater than 70° to avoid material blocking in the future.
（6）The pneumatic gate valve between the large warehouse and the small weighing warehouse needs to be started and stopped repeatedly for a long time, and the reliability and tightness of the long-term use must be ensured.
3.Effect
Since the kiln head and kiln tail pulverized coal metering scales were put into operation in 2017, the equipment has been operating stably. The feeding flow curve is stable, and the system control accuracy has reached the requirements of ±1.0%, and good economic benefits have been achieved.
4.Analysis and Summary
The conventional Coriolis powder material metering system, when the range is less than 2t/h, due to the decrease in the accuracy of the matching sensor and the increase in the difficulty of the mechanical structure design of the scale in this situation, it is difficult to meet the metering requirements for long-term accuracy and stability. However, the micro-weight loss-in-weight powder metering scale has a range design in the range of 0.5 to 2t/h, which just completes the selection of the conventional Coriolis powder metering scale.
The operation of the micro-weight loss-in-weight weighing scale can be regarded as the cycle of the two processes of precise feeding and inertial feeding. Between the two openings of the pneumatic gate valve is a precise feeding process, depending on the design of the weighing bin, generally this process can last for 0.5-1h, due to the use of high-precision weighing sensors, stable and high-precision feeding can be ensured. When the pneumatic gate valve is opened, the feeding period is the inertial feeding process with constant speed of the flow stabilizer, but the feeding process generally only lasts for tens of seconds. Compared with the previous accurate feeding process, it has little effect on the overall metering, ensuring stability and reliability of Long-term accuracy metering.
Judging from the actual use effect of the Malawi project, the control metering accuracy of the micro-weight scale reaches ±1%, the operation is stable and reliable, and the maintenance workload is low, so the design indicators are better achieved.
1.Project Introduction
The 500t/d production line in Malawi, the general contractor of Jiangsu Pengfei Group, selected our company's kiln head and kiln tail pulverized coal metering system. The kiln tail pulverized coal consumption is 1-5t/h, and it use our standard KXT(M)-I Coriolis pulverized coal metering system. However, the consumption of pulverized coal at the kiln head is only 0.9-1.1t/h. The project design company initially planned to use a bypass valve to simply split the pulverized coal pipeline from the kiln tail to the kiln head for use. However, this plan increased the instability of the air conveying system, and the stability and uniformity of the kiln head pulverized coal consumption cannot be guaranteed. Finally，according to our recommendation, kiln head pulverized coal metering adopts our company’s small and trace coal pulverized coal loss-in-weight weighing scale program.
2.Design Program
The process layout of the kiln head and kiln tail pulverized coal metering of the project is shown in Figure 1. The micro-weight loss-in-weight pulverized coal metering scale and the kiln tail pulverized coal metering system are arranged side by side at the bottom of the pulverized coal silo, and the side of the pulverized coal silo cone has holes. Through the pneumatic gate valve and the transition pipe, it is connected to the self-contained weighing silo of the loss-in-weight pulverized coal metering scale.
The key design points of micro-weight loss-in-weight pulverized coal weighing scale:
（1）A weightless warehouse with a high-precision weighing sensor is used as the metering device, the flow is controlled by a flow stabilizer, and the screw pump completes the pneumatic conveying of pulverized coal.
（2）The system control accuracy reaches ±1%.
（3）When installing, we pay attention to the angle of the slide pipe from the large coal bin to the weighing bin, and install a spray device on the slide pipe to ensure the fast and unobstructed feed from the big bin to the small weighing bin.
（4）Must ensure that the material height of the warehouse is within a reasonable range.
（5）Note that the dust collection air volume of the weighing silo and the top silo of the screw pump should not be too large, the connection of the dust collection pipe must be disconnected, and the angle of the collection pipe must be greater than 70° to avoid material blocking in the future.
（6）The pneumatic gate valve between the large warehouse and the small weighing warehouse needs to be started and stopped repeatedly for a long time, and the reliability and tightness of the long-term use must be ensured.
3.Effect
Since the kiln head and kiln tail pulverized coal metering scales were put into operation in 2017, the equipment has been operating stably. The feeding flow curve is stable, and the system control accuracy has reached the requirements of ±1.0%, and good economic benefits have been achieved.
4.Analysis and Summary
The conventional Coriolis powder material metering system, when the range is less than 2t/h, due to the decrease in the accuracy of the matching sensor and the increase in the difficulty of the mechanical structure design of the scale in this situation, it is difficult to meet the metering requirements for long-term accuracy and stability. However, the micro-weight loss-in-weight powder metering scale has a range design in the range of 0.5 to 2t/h, which just completes the selection of the conventional Coriolis powder metering scale.
The operation of the micro-weight loss-in-weight weighing scale can be regarded as the cycle of the two processes of precise feeding and inertial feeding. Between the two openings of the pneumatic gate valve is a precise feeding process, depending on the design of the weighing bin, generally this process can last for 0.5-1h, due to the use of high-precision weighing sensors, stable and high-precision feeding can be ensured. When the pneumatic gate valve is opened, the feeding period is the inertial feeding process with constant speed of the flow stabilizer, but the feeding process generally only lasts for tens of seconds. Compared with the previous accurate feeding process, it has little effect on the overall metering, ensuring stability and reliability of Long-term accuracy metering.
Judging from the actual use effect of the Malawi project, the control metering accuracy of the micro-weight scale reaches ±1%, the operation is stable and reliable, and the maintenance workload is low, so the design indicators are better achieved.
