Dry Cleaning Technology Developments
The use of dry cleaning methods to clean waste plastic films is a key area of related research. Some companies in Japan and Europe are conducting research in this area. For example, the Japanese EINTECS Institute of Technology proposes a dry cleaning technology for waste plastics. Dry cleaning of all waste plastics.
The dry cleaning process does not use water as a medium, and air is generally used as a cleaning medium. Therefore, no waste water is generated, secondary pollution is greatly reduced, and water resources are saved at the same time. In a dry granulation process, dry cleaning and separation of impurities are performed. The combination of the processes can effectively remove the impurities in the waste film, and the purity of the regenerated particles can be improved, which can give full play to the advantages of the dry granulation process.
As the domestic dry cleaning technology for waste plastic films has just started, the cleaning effect of the dry cleaning technology experimental device on waste plastic films needs to be further improved, but it can be used as a pretreatment process before washing, and most of the waste films are removed. Dirt, reduce follow-up water consumption.
The basic requirements for the dry cleaning process of waste plastic film are: The shape is irregular round, the diameter size range is 5 to 15mm, the dryness degree of the waste film is ≤ 1.0% residual moisture, the dry waste film The bulk density is between 10 and 30 kg/cm3.
Dry process mechanism
Principle of dry cleaning process
The dry cleaning of waste plastics is the use of physical forces such as friction, grinding, and impact on waste sheets of a certain thickness and broken to a certain size, so that the waste plastic fragments break with the hard objects, and collisions occur between the fragments and fragments, and friction occurs. Grinding. Adhesion to the dirt on the flake. Under these physical forces, the release film is dispersed in the air medium. The dirt and film pieces released from the film are sent to the dust collector and the cyclone separator for dust removal and separation. , Finally get a clean film sheet.
In this process, there are two factors: the cleaning medium and the cleaning power. The cleaning medium for the dry plastic cleaning of the waste plastic adopts air. Since the generation of the cleaning power is mainly provided by air, the compressed air is used. The cleaning power is used as the physics. Forces, collisions, friction, grinding, etc. The main ways to produce are the collision of the diaphragm with the hard object, the friction, the friction and the grinding between the diaphragm and the diaphragm.
Dry cleaning process
According to the principle of dry cleaning of waste plastics, the process flow consists of three parts: Pretreatment, cleaning, separation In the pretreatment stage, it is necessary to obtain materials suitable for dry cleaning; in the cleaning stage, the dirt on the fragments is detached from the fragments; in the separation stage, the detached dirt and fragments are separated to obtain a clean fragment. The following figure shows the dry method. Scrap plastics cleaning process and equipment schematics.
Pretreatment - Cleaning - Separation
1. Adding material; 2. Crude crusher; 3. Conveyor; 4. Drying coarse washing machine; 5. Crusher; 6. Dust catcher; 7. Washer; 8. Dust catcher; 10. Cyclone Separator; 11. Clean Fragments
Pretreatment of waste plastic before dry process
Because the film is easily curled due to stress, the dirt will be trapped inside and difficult to remove. For this reason, the waste film needs to be pretreated before dry cleaning. The pretreatment method is mainly crushing and drying. Its purpose is to obtain a dry, A certain size scrap film is used to facilitate cleaning with dry cleaning equipment.
In the pretreatment stage, the relatively large sand, mud, small stones, etc., which are entrapped in the waste film, are removed; the dirt, which is difficult to be removed from the adherence on the fragment, is cleaned after entering the cleaning stage, and is then subjected to the separation stage. Cleaner fragmentation.
Dry cleaning machine works
The dry cleaning machine is the cleaning stage subsystem in the waste plastic dry cleaning process system. The core function of the cleaning system of the cleaning machine is to complete the dry cleaning of waste plastic fragments and consists of three parts: Pneumatic conveying part, washing machine part, dust separation part.