How to reduce the energy consumption of WPC extrusion machine?
In the production of wood plastic WPC products, electricity consumption is also one of the main production cost. Reasonable reduction of energy consumption can greatly reduce the production cost of wood plastic products. Here, Yongte professional engineer team gives professional suggestions to help WPC factories reduce energy consumption.
Reducing the energy consumption of WPC extrusion machine needs to start from equipment design, process parameter optimization, daily maintenance and production management, the following are specific methods and suggestions:
temperature control
1. Reasonable setting of temperature in each zone: avoid excessive plasticization of materials and increase energy consumption due to high temperature. According to the characteristics of materials (such as PVC the processing temperature of wood-plastic is usually 160~190℃), optimize the temperature gradient of barrel, die head and mold to ensure uniform plasticization of materials.
2. Reduce temperature fluctuation: use high precision temperature control instrument and cooling system (such as circulating water or oil cooling) to avoid frequent adjustment of power due to unstable temperature.
Screw speed and torque
3. Low speed and high efficiency plasticization: the high speed of the conical twin screw will increase mechanical friction heat and energy consumption. The full plasticization can be achieved at a low speed (usually controlled at 10~30r/min) by optimizing the screw combination (such as adding shear blocks or mixing elements).
4. Monitor torque load: When the torque is too high (such as more than 80% of the rated torque), it may mean that the material is difficult to plasticize, so adjust the formula or reduce the speed to avoid motor overload.
Material formula optimization
5. Reduce high energy consumption raw materials: avoid using too much high melting point filler (such as calcium carbonate) or difficult to plasticize additives, and appropriately increase lubricants (such as stearic acid) to improve fluidity and reduce screw load.
6. Use efficient stabilizers: such as using composite stabilizers to reduce the amount of heat stabilizers and avoid repeated processing energy consumption due to decomposition.
Repair of screw and barrel wear
7. Check the clearance between screw and barrel regularly (normal clearance should be less than 0.5mm). Severe wear will lead to material retention, poor plasticization and increase energy consumption. The clearance can be restored by welding wear-resistant alloy (such as tungsten carbide) or replacing new parts.
8. Choose wear-resistant screw material (such as 38CrMoAl nitriding treatment) to extend service life and reduce friction energy consumption.
Transmission system optimization
9. Gearbox maintenance: replace the lubricating oil regularly (it is recommended to do so every 5000 hours) to ensure good gear meshing and reduce transmission loss (gearbox efficiency should be greater than or equal to 95%).
10. Motor energy saving upgrade: replace the ordinary asynchronous motor with permanent magnet synchronous motor or servo motor (energy efficiency grade IE3 or above), which can improve the efficiency by 10%~20%, especially in low load energy saving effect is significant.
Cooling and heating system improvements
11. Waste heat recovery and utilization: the heat generated by cylinder cooling (such as waste heat of circulating water) is used to preheat materials or workshop heating, reducing energy waste.
12. Optimized heating method: Electromagnetic heating or infrared heating is used to replace traditional resistance heating, the heating efficiency can be increased by more than 30%, and the temperature control is more accurate.
Continuous production and load balance
13. Avoid frequent start and stop of equipment (the energy consumption of a single start is about 3~5 times that of normal operation), and try to keep continuous production for 24 hours to reduce idle time.
14. Balance the production load and avoid running the equipment under low load (such as below 30% rated capacity), because the motor efficiency decreases with the decrease of load.
Operator training
15. Standardize the operation process to avoid energy waste caused by human error (such as improper temperature setting, screw idling, etc.).
16. Train employees to adjust parameters in real time according to the material state (such as judging the degree of plasticization by observing the glossiness of the extruded surface to avoid excessive processing).
Equipment energy efficiency monitoring
17. Install energy consumption metering instruments (such as power transmitter) to monitor the energy consumption ratio of each unit (motor, heating and cooling) in real time, and optimize the high energy consumption links accordingly.
18. Establish energy efficiency assessment indicators (such as energy consumption per unit product, kWh/kg), and set energy saving targets through regular comparative analysis.
Optimization of feeding system
19. Replace the volumetric feeder with the weightless metering feeder to ensure accurate material delivery and avoid screw load fluctuations caused by uneven feeding.
20. Materials with high moisture content (such as wood powder) should be dried in advance (moisture content ≤ 3%) to reduce the additional heat consumed by water evaporation.
Cooling system energy saving
21. The variable frequency pump is used to adjust the cooling water quantity and dynamically adjust according to the production load (for example, when the cooling demand decreases, the pump speed can be reduced to 50%~70%), so as to reduce the energy consumption of the pump.
22. Use closed cycle cooling system to reduce water waste and heat loss.
· A case of transformation of a wood-plastic enterprise: the screw speed was reduced from 28r/min to 22r/min, and the screw combination was optimized (distributed mixing elements were added), and the energy consumption per unit product was reduced from 1.2kWh/kg to 0.9kWh/kg, saving about 300,000 kWh per year.
· Motor upgrade case: Replace the asynchronous motor with a servo motor, combined with frequency conversion control, the current is reduced by 15% under the same output
To reduce the energy consumption of a conical twin-screw extruder, it is essential to follow the principles of precise control, loss reduction, and system optimization. By aligning process parameters with equipment performance, applying energy-saving technologies, and implementing refined production management, a 10% to 30% reduction in energy consumption can be achieved. It is recommended to start with easier-to-implement areas, such as temperature optimization and motor upgrades, and gradually implement systematic improvements.