Polyacrylamide is a widely used additive in the paper industry. Polyacrylamide (PAM), as a water-soluble polymer, has excellent flocculation, thickening, dispersion and other properties. Will be applied to several different processes with different functions. In the papermaking industry, PAM plays an indispensable role. It has brought significant economic benefits to the papermaking industry by improving the properties of pulp and increasing the operating efficiency of paper machines. This article will discuss in detail the application of polyacrylamide in paper production and its effect on improving production efficiency.
Basic properties and functions of polyacrylamide
Polyacrylamide is a high molecular polymer that can be divided into nonionic, anionic, cationic and amphoteric types according to its charge properties. When PAM dissolves in water, and its long-chain molecular structure enables it to have excellent functions such as flocculation, thickening, retention assistance, and filtration assistance. In the paper industry, polyacrylamide is mainly used in the following aspects:
1. Retention aid:
PAM molecules have a long chain structure and can be adsorbed on the surface of fibers and fillers to form bridges. Thereby improving the retention rate of fillers and fibers on the paper web. Reduce fiber loss in white water and reduce raw material loss. By increasing the retention rate of fillers and fibers, the paper’s physical properties such as smoothness, printability, and strength can be improved.
2. Filter aid:
Improve the dewatering performance of pulp, speed up the water filtration process and reduce energy consumption.
3. Flocculant:
Accelerate sludge dehydration: PAM can effectively flocculate small fibers, fillers and other suspended matter in pulp to form large particle flocs, speed up sludge settlement and dehydration, and reduce sludge treatment costs.
Improve water quality: PAM can effectively remove suspended solids and organic matter in wastewater, reduce BOD and COD in wastewater, improve water quality, and reduce environmental pollution.
4. Dispersant:
Prevent fiber agglomeration: PAM can effectively prevent fiber agglomeration in pulp, improve the uniformity of pulp, and improve the quality of paper.
Application of polyacrylamide in papermaking technology
1. Pulp preparation stage
During the pulp preparation process, fine fibers and fillers are easily lost with wastewater, causing resource waste and environmental pollution. Using cationic polyacrylamide as a retention aid can effectively capture and fix small fibers and fillers in the pulp through charge neutralization and bridging. This not only reduces the loss of fibers, but also reduces the loading of sewage treatment.
2. Paper machine wet end system
In the paper machine wet end system, rapid dehydration is the key to improving production efficiency. Anionic or nonionic polyacrylamide can be used as a filter aid to make it easier for water to escape from the fiber network structure by improving the flocculation between fibers. This process significantly shortens dehydration time while reducing energy consumption during the drying phase.
3. Papermaking stage
As a dispersant, polyacrylamide can effectively prevent fiber flocculation and improve the uniformity and surface smoothness of the paper. By carefully selecting the molecular weight and charge density of PAM, the physical properties of the finished paper, such as tensile strength and tear strength, can also be optimized. In addition, polyacrylamide can also improve the coating effect of coated paper and make the printing performance of the paper better.
The core advantages of polyacrylamide in improving production efficiency
1. Reduce raw material loss
The use of retention aids significantly improves the retention rate of fine fibers and fillers in pulp, reduces raw material consumption, and directly saves production costs.
2. Speed up the dehydration process
The introduction of filter aids makes the dewatering process more efficient, thereby increasing the paper machine’s operating speed and shortening the production cycle. This not only increases stand-alone production capacity, but also reduces energy consumption.
3. Reduce wastewater treatment pressure
By improving the flocculation effect, polyacrylamide can effectively reduce the content of suspended solids in wastewater, reducing the loading of sewage treatment facilities from the source and reducing the environmental protection costs of enterprises.
4. Improve paper quality
The use of dispersants makes the fiber distribution of the paper more uniform, significantly improves the physical and visual properties of the paper, and enhances the market competitiveness of the product.
Factors affecting the use effect of polyacrylamide
In order to give full play to the performance of polyacrylamide, the following factors need to be focused on:
1. PAM model selection
Different papermaking processes and paper types have different requirements for the molecular weight and charge density of PAM. High molecular weight PAM is suitable for flocculation and filter aid, while low molecular weight PAM is more suitable for dispersion.
2. Adding amount and adding method
The amount of PAM added must be precisely controlled. Excessive amounts may cause negative effects, such as affecting dehydration performance or increasing production costs. At the same time, a uniformly dispersed addition method should be used to avoid local aggregation that affects the effect.
3. Process conditions
Temperature, pH and water conditions all affect PAM performance. For example, cationic PAM works best in neutral to slightly acidic conditions, while anionic PAM is suitable for alkaline environments.
As a multi-functional additive in the papermaking industry, polyacrylamide plays an important role in improving production efficiency, reducing production costs and improving product quality with its excellent flocculation, retention, filtration and dispersion properties. In practical applications, companies need to reasonably select and optimize the use conditions of PAM based on their own process characteristics and needs to achieve the best economic and environmental benefits.
Post time: Nov-28-2024
