Product recommendation | Application of defoamer in pulp and paper making

The consumption level of paper and cardboard is an important symbol to measure the level of modernization and civilization of a country. With the continuous improvement of people's living standards, everyone has higher and higher quality requirements for various products, and paper is no exception. But many factors are still restricting the improvement of paper quality, among which the foam problem encountered in the paper industry is one of the important factors.

The "black liquor" produced by pulp and paper has been considered as a huge source of pollution in the paper industry. Among them, lignin is not only the main component of "black liquor", but also the "binder" of biomass cell wall substances. According to statistics, about 5,000 tons of lignin are discharged into water bodies with "black liquor" every year.

1. The source of "black liquor" in pulp and papermaking

In the paper industry, wood, straw, reed, rags, etc. are used as raw materials, and cellulose is separated by high-temperature and high-pressure cooking to make pulp. During the production process, the non-cellulose part of the discharged raw material becomes papermaking black liquor.

The black liquor contains lignin, cellulose, volatile organic acids, etc., which has an odor and is highly polluting. Papermaking industrial wastewater is a kind of difficult-to-treat organic wastewater with large water volume, high chroma, high content of suspended solids, high concentration of organic matter, and complex components.

2. Where does the foam in pulp and paper "black liquor" come from?

① In the process of paper pulp washing, the added chemical additives such as bleach react with the chemical components in the "black liquor", and foam will be generated;

② Pollutants such as fatty acid salts and hemicellulose contained in "black liquor" have high viscosity and are not easy to degrade. They are the basic components of surfactants, which reduce the surface tension of aqueous solution and are easy to foam;

③ Due to the existence of excess alkali, incompletely precipitated rubber material and slurry fermentation, etc., the "black liquor" will generate foam.

3. The impact of foam in pulp and paper "black liquor"

1. The production and processing of the papermaking process will be affected, resulting in production stagnation and reduced production efficiency.

2. Affect the surrounding environment, so that the sewage cannot meet the discharge standards and affect the water quality monitoring work.

3. Foam will also affect the concentration fluctuation of the headbox, making the flow of paper material unstable, causing problems such as paper breaks. The quality of the follow-up paper is reduced, and the pressure of the pulp tank replaced by the press is increased.