Compression pretreatment technology for wood drying and impregnation

1. Technical Introduction

By pre-treating high-moisture logs and sawn timber with compression, the moisture content of the wood is significantly reduced in a very short period of time, reducing the likelihood of blueing during the long-term air-drying process and shortening the drying cycle. Furthermore, compression drying pre-treatment squeezes the wood to squeeze out the moisture while maintaining its liquid state. This not only saves a large amount of vaporization energy but also effectively releases growth stress in the wood, opening up moisture channels within the wood, which plays a positive role in reducing drying defects and accelerating the drying process.

By pre-treating logs and sawn timber with compression, the rapid rebound after compression release creates a pressure differential between the inside and outside of the wood, allowing various functional modifiers to continuously penetrate the wood. Furthermore, compression pre-treatment disrupts the wood's internal microstructure, creating additional infiltration channels, further increasing the infusion speed, volume, and depth.

2. Technical Features

By using the compression pretreatment technology of drying and impregnation, the size retention rate of the treated wood can reach more than 90%, protecting the precious wood resources, while its mechanical properties are almost not lost or even slightly increased.

This achievement not only encompasses the compression pretreatment process technology for wood drying and impregnation during industrial production, but also includes the research and development of related equipment, tailored to the requirements of the process technology. This equipment serves as a vehicle for industrial production, providing comprehensive support for its widespread industrialization. The rational design of this equipment significantly reduces machining precision requirements and the number of components, thus saving equipment costs while maintaining performance.

The technology is not only suitable for sawn timber, but also for logs.

3. Market Prospects

This achievement is suitable for transformation and promotion demonstration in the field of wood drying and impregnation modification. This achievement can greatly reduce the moisture content of high-moisture wood in a very short period of time, solving the problems of long drying cycles and easy blue discoloration of traditional wood. The subsequent drying of pretreated wood, on the one hand, has a fast drying speed because the pit membrane does not shift and has good moisture transfer channels; on the other hand, because the growth stress of the wood is well released during the compression pretreatment process, the drying defects of the wood are reduced and the drying quality of the wood is improved. Therefore, it has good application prospects in the field of wood drying. The economic benefits of this technology in solving the blue discoloration problem, shortening the drying cycle, reducing drying energy consumption, and improving drying quality are immeasurable.

At the same time, the amount of liquid impregnated into wood treated by this system can be increased by at least several times. Therefore, it has promising prospects for industrial applications in wood modification processes, such as dimensional stability treatment, wood strengthening, wood fireproofing, and wood corrosion resistance treatment. The resulting improved fire and corrosion resistance of wood products will generate significant economic benefits.

With the increasing awareness of fire safety of wood products and the increasing requirements for the durability of wood for outdoor use, especially the increasing national requirements for fire prevention and outdoor corrosion resistance of wood products, wood compression pretreatment will inevitably have a good application prospect.