Analysis of Energy Consumption of Co Rotating Twin Screw Extruder

Parallel co-rotating twin-screw extruder is a common plastic compounding machine, which is widely used in the plastic products processing industry. The extruder mainly compose of main motor, electrical control system, feeding system, frequency converter,  temperature control system, pressure sensor.The molten material is mixed and extruded through the rotary motion of the twin screws.

Energy consumption is an important consideration in the extrusion process.

There are two main factors for energy consumption: 

• one is the friction generated by the rotation of the two screws

• The second is the loss of energy in the heating and cooling system.

The two intermeshing the screw generates frictional heat, resulting in energy loss. In order to reduce the frictional resistance of the screw, various methods can be used to reduce the coefficient of friction between the screw and the wall plate. For example, a ceramic coating can be applied to the surface of the screw to increase the sliding balance between the screw and the wall plate, reduce the generation of frictional heat, then reduced energy loss.

Energy loss in heating and cooling systems is also an important factor for energy consumption. In the compounding extrusion process, the heating and cooling system needs to provide sufficient heat energy as well as cooling capacity to achieve accurate temperature control at different operations during the extrusion process. In order to reduce energy loss, the following measures can be taken: First, the use of energy-saving heating and cooling systems, such as energy-saving electric heating cylinders, with high thermal efficiency and energy utilization; The second is to reasonably design the control mode of the heating and cooling system, and adjust the operating frequency and power of the heating and cooling system according to the actual situation of heating and cooling demand to reduce energy consumption.

The electronic control system of the twin screw extruder is also an important factor affecting energy consumption. At present, many extruders are equipped with advanced  control systems with a variety of energy-saving measures, such as inverter control systems, power recovery technology, etc. The inverter control system can adjust the speed and power of the screw according to the actual working load and needs of the extruder to reduce energy consumption. The power recovery technology can recover the electrical energy generated when the screw is moving and reuse it to other equipment or systems to improve energy efficiency.