Sulfur Recovery Daily Question 2019.1.14
Thread Content
What is boiler corrosion? What are the harms of boiler corrosion to the boiler? Answer: Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, the corroded pressure-bearing components may fail to withstand the intended pressure without anyone noticing, leading to catastrophic accidents. The corrosion of boiler metal not only shortens the service life of the equipment itself, but also, as the products of metal corrosion enter the water, it increases the impurities in the water, thereby accelerating the scaling process on the surfaces exposed to high heat loads. This, in turn, promotes corrosion beneath the scale, and such a vicious cycle can lead to accidents such as boiler tube failures.
Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, if not noticed, the corroded stressed components may fail to withstand the design pressure and cause accidents. Metal corrosion in boilers not only shortens their service life; the products of this corrosion end up in the water, accelerating the formation of scale and leading to further corrosion beneath the scale.
Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, if not noticed, the corroded stressed components may fail to withstand the design pressure and cause accidents. Metal corrosion in boilers not only shortens their service life; the products of this corrosion end up in the water, accelerating the formation of scale and leading to further corrosion beneath the scale.
Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, if not noticed, the corroded stressed components may fail to withstand the design pressure and cause accidents. Metal corrosion in boilers not only shortens their service life; the products of this corrosion end up in the water, accelerating the formation of scale and leading to further corrosion beneath the scale.
Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, the corroded pressure-bearing components may fail to withstand the intended pressure without anyone noticing, leading to catastrophic accidents. The corrosion of boiler metal not only shortens the service life of the equipment itself, but also, as the products of metal corrosion enter the water, it increases the impurities in the water, thereby accelerating the scaling process on the surfaces exposed to high heat loads. This, in turn, promotes corrosion beneath the scale, and such a vicious cycle can lead to accidents such as boiler tube failures.
Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, the corroded pressure-bearing components may fail to withstand the intended pressure without anyone noticing, leading to catastrophic accidents. The corrosion of boiler metal not only shortens the service life of the equipment itself, but also, as the products of metal corrosion enter the water, it increases the impurities in the water, thereby accelerating the scaling process on the surfaces exposed to high heat loads. This, in turn, promotes corrosion beneath the scale, and such a vicious cycle can lead to accidents such as boiler tube failures.
Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, the corroded pressure-bearing components may fail to withstand the intended pressure without anyone noticing, leading to catastrophic accidents. The corrosion of boiler metals not only shortens the service life of the equipment itself, but also, as the metal corrosion products enter the water, they increase the impurities in the water, thereby accelerating the scaling process on the surfaces exposed to high heat loads. This, in turn, promotes under-scale corrosion, and such a vicious cycle can lead to accidents such as boiler tube failures
Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, the corroded pressure-bearing components may fail to withstand the intended pressure without anyone noticing, leading to catastrophic accidents. The corrosion of boiler metal not only shortens the service life of the equipment itself, but also, as the products of metal corrosion enter the water, it increases the impurities in the water, thereby accelerating the scaling process on the surfaces exposed to high heat loads. This, in turn, promotes corrosion beneath the scale, and such a vicious cycle can lead to accidents such as boiler tube failures.
Answer: Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. What’s more serious is that certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength to such an extent that it goes unnoticed by people
During the combustion process, the flue gases from boilers often contain various corrosive gases and substances, such as sulfur oxides. These substances cause severe corrosion to boilers, and in serious cases, they can damage the boilers in a very short period of time. When flue gas entering the boiler contains sulfur dioxide, a portion of it is converted into sulfur trioxide, which then combines with water vapor in the flue gas to form sulfuric acid vapor. This raises the dew point temperature of the flue gas significantly, allowing sulfuric acid solutions to condense on low-temperature metal surfaces. These solutions react with alkaline ash as well as with the metal itself, thereby causing corrosion. It is called low-temperature corrosion because it often occurs on the low-temperature heating surfaces of boilers. Low-temperature corrosion is characterized by uniform corrosion, which gradually reduces the thickness of the tube wall until it ruptures, posing a serious threat to the safe operation of boilers. The flue gas contains not only sulfur trioxide but also water vapor, and they interact to produce sulfuric acid vapor. If the tube wall temperature falls below a certain value, sulfuric acid vapor will condense on the tube wall, causing corrosion. Scale can cause corrosion of the metal beneath it. When there is scale attached to the heating surfaces of a boiler, the boiler water that seeps in through the pores and gaps in the scale evaporates rapidly between the deposited scale layer and the boiler’s heating surfaces. Below the scale layer, the water in the boiler can be concentrated to very high levels. Some of these substances can cause severe corrosion to the heating surfaces of boilers under high temperature and high concentration conditions, such as NaOH. The processes of scaling and corrosion reinforce each other, which can quickly lead to damage to the metal heating surfaces, thereby causing tube failures in the boiler. Chemical descaling includes alkali washing and acid washing. The alkali cleaning method involves injecting alkali solutions of different types and concentrations into the boiler, and then boiling it under certain pressure; usually for 48 hours or even longer, in order to achieve the purpose of alkali cleaning. During pickling for scale removal, the acid not only eliminates scale from the heating surfaces of the boiler, but it also reacts with the metal, thereby causing corrosion or perforation of the boiler. Therefore, the technical requirements for acid cleaning are quite high; generally, no organizations or individuals are allowed to carry out acid cleaning and scaling removal tasks without approval. When descaling a boiler with acid cleaning, it is necessary to hire a company with the appropriate expertise for such acid cleaning tasks. This pickling unit must hold a chemical cleaning license issued by the boiler and pressure vessel safety supervision department.
Poor boiler water quality can cause metal corrosion, leading to thinning and warping of metal components, or even perforation. Worse still, certain types of corrosion can damage the internal structure of the metal, significantly reducing its strength; as a result, if not noticed, the corroded stressed components may fail to withstand the design pressure and cause accidents. Metal corrosion in boilers not only shortens their service life; the products of this corrosion end up in the water, accelerating the formation of scale and leading to further corrosion beneath the scale.