In recent years, with the increasingly strict requirements of the country for desulfurization, most thermal power plants have adopted wet desulfurization
Before the sulfur process, although the flue gas contains a lot of sulfur dioxide, the temperature of the flue gas entering the chimney is relatively high, up to 130-160 ℃,
Only a small amount of smoke condensation is formed, and the anti-corrosion requirements for chimneys are not very high. However, after wet desulfurization, the temperature of the flue gas decreases
When the temperature reaches 50-80 ℃, the moisture content of the flue gas is high, which leads to an increase in the corrosion rate of the chimney wall. To address severe corrosion
The problem is that fiberglass chimneys have the advantages of good corrosion resistance, lightweight and high strength, long service life, easy construction, and no need for maintenance
This provides the best solution and has been widely promoted and applied.
1. Characteristics of fiberglass materials
Fiberglass reinforced plastics, an academic term for fiberglass reinforced plastic, is composed of glass fibers and
A high-performance mixture formed by the organic combination of resin matrix. It is similar to traditional chimney materials such as reinforced concrete, steel, brick, etc
Compared in terms of quality, it has the following advantages:
1 Corrosion resistance
Fiberglass has excellent corrosion resistance and can resist corrosion from various media including acid, alkali, salt, etc. Table 1 lists
The fiberglass reinforced plastic made of epoxy vinyl ester resin is resistant to strong acid and high chloride corrosion. After extensive research and experimentation
After testing and trial use, it was found that fiberglass material is the best anti-corrosion material.
2 Lightweight and High Strength
Fiberglass has the physical properties of lightweight and high strength, with a specific gravity of only 1/4 of steel. It is mechanically wound to form fiberglass in circumferential tension
The strength can reach 1000Mpa, the axial tensile strength can reach 300Mpa, and the tensile strength of Q235 is 370-500Mpa. Fiberglass reinforced plastic
The specific strength is much higher than that of steel.
3. Low thermal conductivity
Fiberglass has good insulation performance, and its thermal conductivity is much lower than that of steel. In situations where insulation is needed, glass
Fiberglass equipment may not require insulation layers; The thermal expansion coefficient of fiberglass is relatively small and close to that of steel, so it is more suitable for heights
Chimneys with low temperature and small temperature differences may not require expansion joints. See Table 2 for details:

Project Material	Fiber wrapped fiberglass reinforced plastic	Steel	PVC
Thermal expansion coefficient (10-6/℃)	11.2	12.3	60-80
Thermal conductivity coefficient (W/m ·℃)	0.23	41	0.18

4. Long service life
The service life of fiberglass is relatively long, and there is already 40 years of experience in using fiberglass chimneys abroad. According to ASTM D in the United States
The 5364 standard stipulates that the service life of using fiberglass inner tubes should reach 35 years.
5 Cost
If we consider the entire lifespan of engineering structures, the total cost of fiberglass chimneys is more competitive compared to chimneys made of other materials because
Fiberglass material has the advantages of corrosion resistance, lightweight and high strength, long service life, and low maintenance and repair costs, which make its overall cost
Relatively low. Taking a chimney with a height of 240 meters and a diameter of 8 meters as an example, the cost of chimneys made of various materials will be calculated
Comparison, see Table 3 for details:
Table 3 Cost comparison of chimneys made of different materials

Steel foam glass brick	18 million yuan
Steel titanium composite structure	21 million yuan
Integrated fiberglass sleeve	15 million yuan

2. Fiberglass construction technology
At present, the forming process of fiberglass chimneys is mainly automated mechanical winding forming. Advantages of fiberglass winding molding: ①
Being able to design winding rules according to the force conditions of the product, so as to fully utilize the strength of the fibers; ② High intensity ratio: Generally speaking,
Compared with steel containers of the same volume and pressure, fiber wound pressure vessels can reduce weight by 40-60%; ③ High reliability:
Fiber wrapped products are easy to achieve mechanization and automation production. After the process conditions are determined, the quality of the wrapped products is stable and accurate;
④ High production efficiency: adopting mechanized or automated production, requiring fewer operators and fast winding speed (240m/min), therefore
High labor productivity; ⑤ Low cost: Multiple materials (including resin, fiber, and lining) can be reasonably selected for the same product,
Recombine it to achieve the best technical and economic results. The fiberglass chimneys manufactured now are all computer-controlled and automated winding.
3. Application of fiberglass reinforced plastic in thermal power plants
3.1 Application of fiberglass chimneys abroad
The application of fiberglass chimneys abroad began in the 1970s, as early as 1977, in East Kentucky, USA
Power Cooperative has successfully used fiberglass chimneys (height 802ft, 245m, straight) at Spurlock power station
The diameter is 15.5ft and 4.73m, and it is still in safe use today. The number of fiberglass chimneys built in the United States from 2004 to 2008,
As shown in Table 4. Some typical chimney usage cases in various countries are shown in Table 5.
Table 4The number of fiberglass chimneys constructed in North America in recent years [4]

Era	2004	2005	2006	2007	2008
Fiberglass chimney Construction quantity	33	35	38	49	53

Table 5Construction and use of FRP chimneys abroad

Location	Remarks	year
Spurlock Power Statio, a subsidiary of East Kentucky Power Cooperative in the United States	Chimney diameter 4.73m, height 245	In 1977
Cross Generating Power Station owned by Santee Cooper in the United States ​	Chimney diameter 8.54m, height 148.8m	In 2004
Kraftwerk Simmering Power Station, Germany	Chimney diameter 8.54m, height 148.8m	In 2001
Ingolstadt Power Plant, Germany	Chimney diameter 6.7m, height 180m	In 1993
Kansai Electric Power Nangang Power Plant in Japan	The inner diameter of the chimney is 5.3m, and the length of the pipe section is 11m. It is assembled from 51 fiberglass pipe sections	In 1992
Eggborough Power Station, UK	Two 184m FRP inner tubes were installed on two 500MW units	In 2002
Neideraussen power station in Germany	1000MW unit	In 2003
Voiklingen Experimental Power Plant in Germany	300MW unit	In 1982
Schwarzee Pumpe Power Station in Germany	2 × 800MW units	In 1997
Weisweiler Power Plant in Germany	2300MW Unit
Lippendorf Power Plant, Germany	2 × 920MW units
Czech Republic's Vresova Power Plant	125MW Unit	In the year 2000

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In 2007, the P4 power plant in the United States completed a desulfurization renovation and built a new double inner chimney designed by Pullman Power,
The outer cylinder is a reinforced concrete structure with a height of 131.064m and a diameter of 20.599m, while the inner cylinder is an FRP structure with a diameter of 8.1m and made of resin
Using HetronFR992 resin. On site winding and installation of the inner cylinder, each inner cylinder is divided into 12 sections with a length of 9.144m during production.
In 2002, Eggborough Power Station in the UK installed wet flue gas desulfurization (FGD) systems on two 500 MW units,
At the same time, two 184 meter FRP inner tubes were installed inside the concrete chimney.
In July 2000, the 125 MW Vresova power plant in the Czech Republic signed a contract to install a wet flue gas desulfurization system, with a steel chimney
FRP chimney with structural support
The Kraftwerk Simmering power station, built in Germany in September 2001, uses a height of 200 meters and a diameter of 4.8 meters
FRP chimney In addition, Germany is also the world's first to adopt tower to tower technology, using FRP to manufacture rows with a diameter of 7-10 meters
Smoke ducts
In Japan, the 800 MW unit of Kansai Electric Power Nangang Power Plant adopts a chimney with three FRP inner tubes, with a diameter of FRP inner tubes
5.3 m, Height 200 meters
Years of research and engineering applications abroad have formed the design, manufacturing, and construction of FRP chimney or pipeline structures
Surface standards, such as ASTM D 5364 in the United States.
3.2 Application of domestic fiberglass chimneys
China lags behind developed Western countries in the research and application of fiberglass chimneys, but in recent years, fiberglass chimneys have become increasingly popular
Spring shoots continue to emerge, and currently completed projects include the Hutubi Power Plant in Xinjiang, the Hushan Power Plant in Huaibei, Anhui, and the Liaodong Bay Thermal Power Plant in Panjin. Preparations are underway and underway
The construction includes power plants such as Chongqing Shizhu Power Plant, Taiyuan Second Thermal Power Plant, and Shandong Binzhou Power Plant.
Major power design institutes and provincial power design institutes have currently considered fiberglass chimneys as the main alternative design.
Our company is a participating unit in the drafting of the national standard GB30811-2014 for the inner tube of glass fiber reinforced plastic chimneys in coal-fired power plants.
4. Comparison between fiberglass chimney inner tube and titanium plate
Titanium is a material with excellent corrosion resistance, which is due to the formation of a stable passivation film on the surface of titanium. Therefore, it is prone to corrosion in acidic environments
The titanium plate solution has good stability in alkaline, neutral salt solutions, but it has the following disadvantages:
(1) The cost of titanium plate is very high, and it is the most expensive among all the options.
(2) The manufacturing cycle of titanium plates is also the longest, taking at least 3-4 months from ordering to delivery, and even up to half a month
Years or more.
(3) The welding seam treatment of titanium plate is a very complex problem, and the welding process technology of titanium plate itself is very difficult
Ordinary welders can carry out construction work and must undergo specialized technical training. At the same time, as many constructions are carried out at high altitudes, welding
The difficulty of connection is very high, so many quality problems of titanium plate chimneys mainly occur near the welds.
(4) Due to the different coefficients of expansion between titanium alloy and steel plate, cracks are prone to occur.
5. Opinions and suggestions
Compared with the titanium plate inner cylinder, the fiberglass chimney inner cylinder has better corrosion resistance, is lightweight, high-strength, easy to install, and uses
Long lifespan, easy maintenance and other advantages, with broad market prospects.
With the introduction of relevant national standards, such as GB50051 "Chimney Design Specification" and GB30811-2014, the design and manufacturing of fiberglass reinforced plastic chimneys for coal-fired power plants are specified in the standards for the inner tube of glass fiber reinforced plastic chimneys
With clear regulations, this will also promote the wider application of fiberglass chimneys in the power industry.