Material selection for acid- and alkali-resistant pipes

 

Under the current environment of gradual industrial transformation and upgrading, the desulfurization system of power plants has become increasingly important, especially under the increasing environmental protection requirements around the world. One of the key components of the desulfurization system of power plants is the dedicated acid-alkali resistant pipe. This article will analyze in detail the structure, materials, applications and future development trends of the dedicated acid-alkali resistant pipes for corrosion-resistant power plant desulfurization systems.

 

Necessity of acid-alkali resistant pipes

 

It is well known that power plants release a large amount of sulfur dioxide (SO2) when burning fossil fuels. These gases combine with moisture and oxygen in the air to form acid rain, which causes serious harm to the environment. Therefore, in order to limit the air pollution that may occur during the power supply process, many power plants have installed desulfurization systems to remove harmful gases from flue gas.

 

In such a desulfurization process, acid and alkali substances are inevitably produced, and if the pipes used to handle these substances are not corrosion-resistant, they will be severely damaged and even affect the operation of the entire system. The emergence of acid-alkali resistant pipes has become one of the most important components of the desulfurization system of power plants, which can effectively ensure the durability and safety of equipment.

 

Material selection for acid- and alkali-resistant pipes

 

The most commonly used materials for acid- and alkali-resistant pipes include stainless steel, plastic, and fiberglass reinforced plastic (FRP). Each material has its own unique properties and scope of application. In the selection process, chemical properties, physical strength, and cost factors need to be fully considered.

 

Stainless steel materials

 

Stainless steel is widely used in desulfurization systems due to its corrosion resistance and high mechanical strength. Commonly used are 316 and 317 stainless steels, which have good acid resistance and long service life, and can remain stable even under high temperature conditions. However, the cost of stainless steel is higher than other materials, and stress corrosion may occur in some high-concentration chloride ion environments.

 

Plastic materials

 

Plastic materials are widely used due to their superior chemical resistance and low cost, including fluoroplastics (such as polyvinylidene fluoride PVDF) and polypropylene (PP). Although these materials do not perform well under extreme temperature and pressure conditions, their excellent corrosion resistance and low cost make them the preferred materials for some power plants.

 

Fiberglass reinforced plastic (FRP)

 

As a composite material, FRP has a unique structure that enables it to perform well in terms of corrosion resistance and mechanical strength. Compared with stainless steel and plastic materials, FRP can withstand higher temperatures and pressures, and its light weight makes it easier to install and maintain the piping system. Therefore, FRP has become the choice of more and more modern power plant desulfurization systems.

 

Types and Applications

 

In the desulfurization system of a power plant, acid-alkali resistant pipelines are mainly divided into flues, scrubber pipelines, mud conveying pipelines, etc. Each type has different requirements for pipeline materials and structures.

 

Flue

 

The flue is a channel used to guide the flow of flue gas in the pipeline system. It requires long-term contact with high-temperature, corrosive gases containing sulfur compounds, so the corrosion resistance of the material is extremely high. Here, 316 stainless steel or Teflon-coated steel is mostly selected, which can effectively extend the service life of the flue.

 

Scrubber Pipeline

 

The scrubber is an important component of the desulfurization system, and its function is to wash away sulfur and other impurities in the flue gas. The pipeline here must be able to withstand the erosion caused by strong acid and alkali mixtures, and withstand the high temperature and high pressure washing process. Composite materials such as FRP or pipelines lined with corrosion-resistant coatings are ideal choices.

 

Mud pipeline

 

The slurry transported by the mud pipeline often contains unreacted chemicals and is highly corrosive. Therefore, the material selection needs to consider the wear resistance and good mechanical strength of the material. Polyurethane lined steel pipes, wear-resistant ceramic steel pipes, etc. perform well in this field.

 

Future development trends

 

With the improvement of environmental protection standards and the continuous advancement of technology, the materials and structures of acid- and alkali-resistant pipelines dedicated to the desulfurization system of power plants are also continuously improving. In the future, we can foresee:

 

1. Application of new composite materials: Lighter and more high-temperature resistant materials will be developed and used, and these materials may have better corrosion resistance and mechanical stability.

 

2. Intelligent maintenance: With the development of the Internet of Things and artificial intelligence technology, real-time monitoring and predictive maintenance of acid- and alkali-resistant pipelines will become more popular. Sensors combined with data analysis provide more comprehensive data support for the maintenance of pipeline systems, extend pipeline life, and reduce the occurrence of unexpected failures.

 

3. Green manufacturing: Environmentally friendly production processes and the use of recyclable materials will become a trend. In terms of overall layout and pipeline selection, power plants will tend to choose solutions that reduce carbon emissions and environmental impact.

 

4. Customized design: The specific needs and site conditions of each enterprise are different. Personalized and customized acid- and alkali-resistant pipes will become more and more popular and can better meet various complex usage scenarios.

 

In summary, the application of corrosion-resistant pipes in power plant desulfurization systems is of great significance. It not only improves the work efficiency and safety of the system, but also plays an indispensable role in meeting environmental protection standards. With the iterative upgrading of technology, the development prospects of acid- and alkali-resistant pipes in the future power industry are worth looking forward to.