Necessity of anti corrosion of chimney
Main causes of chimney wall corrosion is sulfuric acid and sulfur dioxide, when the internal corrosion of chimney, the chimney body will be exposed reinforcement in flue gas, endanger the safe operation of the chimney, the chimney wall corrosion of the importance of self-evident.
The inner wall anticorrosion method is usually adopted to reinforce the inner wall corrosion resistance, usually the use of paint or building materials and good anti-corrosion performance to improve corrosion resistance, anti-corrosion concrete construction method depends on the specific circumstances, the following 5 factors must be taken into account:
1, technical feasibility. Meet the requirements of complex chemical environment;
2, economic and reasonable. Low cost of construction, less one-time investment;
3, easy construction, short cycle;
4, suitable for old chimney anti-corrosion transformation, light weight;
5, long service life. The reliable running period of anticorrosion lining is long service life
Chimney anti-corrosion can not pay attention to the link
The construction of chimney anticorrosion works is usually to improve the corrosion resistance of the chimney. Jiangsu star high altitude that chimney anti-corrosion should not only be a temporary solution, but also need to cure.
To improve the anti-corrosion capacity of the chimney, one is to provide the surface of the chimney anti-corrosion ability, two is to reduce the amount of corrosion of flue gas emissions. By improving the combustion technology and emission technology, we can reduce the content of corrosive substances in emissions.
Properties of flue gas medium
The corrosive properties of acid and alkali media, first of all, depend on their strength. Strong acid (such as sulfuric acid, nitric acid, hydrochloric acid), alkali (e.g., sodium hydroxide) have greater corrosion of building materials. The destructive oxygen acid of organic materials: maximum corrosion of concentrated sulfuric acid and nitric acid on wood and asphalt. In a short period of time will lose material strength. The same intensity of oxygen acid and deoxygenated rot turbidity of inorganic materials roughly equal. Hydrofluoric acid is very corrosive to many organic and inorganic materials, but has a strong corrosive effect on silica and silica containing materials such as glass, ceramics, etc.. Moderate phosphoric acid and weak acid have little or no corrosion to organic materials, such as phosphoric acid.
In the alkaline medium. The caustic corrosive. Alkaline carbonate (sodium carbonate) times. The turbidity of ammonia aqueous solution is relatively small, because it has low degree of dissociation in aqueous solution, and the volatility is large. There are two chemical and physical aspects of the corrosion of salt solutions. Under the condition of dry wet alternation and temperature change, most of the salt solution will appear the crystal expansion, so it has the physical damage to the concrete, brick masonry, wood and other materials. The sodium sulfate, potassium, ammonium, magnesium, copper, iron and so are the most toxic to the concrete and clay brick. The corrosion of concrete in steel and reinforced concrete is greater than that of chloride.
To do a good job of chimney anti-corrosion work, one from the source control, from the chimney wall and improve the corrosion resistance of the chimney wall, the two links do, is the best chimney anti-corrosion construction works.
Discussion on Anticorrosion of chimney lining
Limestone / lime gypsum wet FGD is a common construction technology. In process control of sulfur dioxide emissions in addition to the use of coal, coal briquette, circulating fluidized bed combustion technology measures, flue gas desulfurization technology is the most widely used of the technology, technology is more mature, reliable and stable operation of the device is very. Discussion on Anticorrosion of chimney lining
When the concentration of sulfuric acid in the inner wall of the chimney is concentrated in the middle state (the concentration of sulfuric acid is 15%, the maximum concentration can reach up to 40%):
The corrosion rate of C25 concrete is 8mm/10 days;
The corrosion rate of C30 concrete is 2.4mm/10 days;
The corrosion rate of C50 concrete is 2.4mm/10 days.
The necessary condition for safe operation of power plant chimney is that the reinforced concrete outer cylinder is not corroded by the flue gas. In order to achieve the purpose of effective anti-corrosion, it is necessary to ensure that the anti-corrosion materials in various operating conditions and temperature can effectively resist the corrosion of flue gas. Due to the change of flue gas composition, pressure and temperature (humidity) after desulfurization, it is necessary to choose a suitable anti-corrosion lining system to prevent corrosion of the steel tube chimney.
According to the analysis of the working condition of the chimney, it is required that the lining material has the ability to resist the strong acid corrosion and the ability to resist the temperature difference. The following factors should be taken into account in selecting the proper inner lining of chimney steel:
(1) technical feasibility. Meet the requirements of complex chemical environment.
(2) economic rationality. Low cost of construction, less one-time investment.
(3) easy construction, short cycle.
(4) suitable for the old chimney anti-corrosion transformation, light weight.
(5) long service life. The reliable running period of anticorrosion lining is long service life.
Chimney anti-corrosion three stages: 1, the organization of the construction of the 2, start management, construction management, 3.