Waste board recycling system and its improvement measures in particleboard production

Defective particleboard blanks (waste blanks) produced in particleboard production need to be removed and recycled. Currently, there are two commonly used recycling methods both domestically and internationally: the first is recycling using a scraper conveyor (see Figure 1), and the second is recycling using a pneumatic conveying system (see Figure 2). Each recycling method has its advantages and disadvantages, and each factory should choose the appropriate method based on its site layout and installation space.

1. Scraper conveyor system for recycling waste slabs

1) Advantages. First, it has a compact structure. The process layout of using scraper conveyors to transport waste slabs requires the waste slab silo to be as close as possible to the forming line's recycling section, saving space in the planar layout. In contrast, pneumatic recovery systems occupy much more space than scraper conveyors and require ductwork, cyclone or bag filters, fans, etc. Second, it requires less investment. A single large-angle scraper conveyor can directly transport waste slabs to the waste slab silo. Third, it has low power consumption. Scraper conveyors have a large conveying capacity but slow operating speed, and their installed power is much lower than that of pneumatic recovery systems. The number of power configuration points in a pneumatic recovery system, including fans, unloading screws, and rotary unloading valves, also exceeds that of scraper conveyors.

2) Disadvantages. First, the scraper conveyor has a large tilt angle, which places very high demands on its manufacturing and operation monitoring. Second, the maintenance cost is high. The scraper chain, sprocket, scraper, and travel track of the scraper conveyor are all vulnerable parts, and replacing them after damage is not only expensive but also time-consuming.

2. Pneumatic waste slab recovery system

1) Advantages and disadvantages.

The advantage of pneumatic waste slab recycling systems is that they are not constrained by floor plan layout and installation space. Many projects are limited by site layout, with recycling silos far from the paving section, and the height of the recycling silos is not suitable for scraper conveyors, so pneumatic recycling systems are the only option. The disadvantages are: first, the investment is higher than that of scraper conveyors; second, the operating power consumption is relatively high (power consumption can be saved through reasonable frequency conversion control); and third, it is prone to clogging during recycling operation.

2) Technical improvement measures to solve the problem of easy clogging in the pneumatic waste slab recovery system.

3. Conclusion

The proper functioning of the waste slab recycling system in particleboard production is crucial. Immediate waste slab removal and recycling are necessary in case of metal alarms, substandard slab quality or moisture content, or press and post-processing malfunctions. A common problem encountered during production is material blockage in the recycling system. Blockage forces the laying system and upstream processes to shut down, impacting production efficiency and causing product quality fluctuations. Limited process space in this area leads to low efficiency, long processing times, harsh cleaning environments with high dust levels, and demanding work conditions for maintenance personnel. Through practical exploration, a technical modification was implemented, completely resolving the blockage problem in the pneumatic waste slab recycling system. This modification is simple, practical, and cost-effective, making it a valuable reference for the industry.

Authors: Chen Yaoli1, Shen Jiaxiong1, Zhang Lizhen1, Meng Qingyou1, Xiong Xiangwei2, Xu Yeming3

Entities: 1. Shandong Heze Maosheng Wood Industry Co., Ltd.; 2. Guangxi State-owned Paiyangshan Forest Farm; 3. Guangxi State-owned Sanmenjiang Forest Farm, Liuzhou, Guangxi 545006

Source: China Wood-based Panels, Issue 3, 2019