One Question per Day (March 14)

Answer key: (1) Affected by the temperature of the heating surface, when this temperature is too low, water vapor or sulfuric acid vapor in the flue gas condenses on the heating surface, causing the fly ash to stick to it. (2) Effect of flue gas velocity ； If the flue gas velocity is too low, ash buildup on the heating surfaces is likely to occur; however, if the velocity is too high, severe wear on the heating surfaces takes place. (3) Effect of fly ash particle size: The smaller the fly ash particles, the larger their relative surface area, which makes them more susceptible to adsorption on metal surfaces. (4) Influence of airflow conditions and tube arrangement: As the velocity increases, airflow disturbances become more severe in staggered tube arrays, and the loose dust accumulation on the tubes is easily blown away. The smaller the longitudinal pitch of the staggered tubes, the greater the airflow disturbances and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in aligned tube arrays, serious dust accumulation occurs on all tubes except those in the first row.

1. Affected by the temperature of the heating surface, when this temperature is too low, water vapor or sulfuric acid vapor in the flue gas condenses on the heating surface, causing the fly ash to stick to it. 2. Influence of flue gas velocity ； If the flue gas velocity is too low, ash buildup on the heating surfaces is likely to occur; however, if the velocity is too high, severe wear on the heating surfaces takes place. 3. Influence of fly ash particle size: The smaller the fly ash particles, the greater their relative surface area, which makes them more susceptible to adsorption on metal surfaces. 4. Influence of airflow conditions and tube arrangement: As the velocity increases, airflow disturbances become more severe in staggered tube arrays, and the loose dust accumulation on the tubes is easily blown away. The smaller the longitudinal spacing between the staggered tubes, the greater the airflow disturbances and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in aligned tube arrays, serious dust accumulation occurs on all tubes except those in the first row.

(1) Affected by the temperature of the heating surface, when this temperature is too low, water vapor or sulfuric acid vapor in the flue gas condenses on the heating surface, causing the fly ash to stick to it. (2) Effect of flue gas velocity ； If the flue gas velocity is too low, ash buildup on the heating surfaces is likely to occur; however, if the velocity is too high, severe wear on the heating surfaces takes place. (3) Effect of fly ash particle size: The smaller the fly ash particles, the larger their relative surface area, which makes them more susceptible to adsorption on metal surfaces. (4) Influence of airflow conditions and tube arrangement: As the velocity increases, airflow disturbances become more severe in staggered tube arrays, and the loose dust accumulation on the tubes is easily blown away. The smaller the longitudinal pitch of the staggered tubes, the greater the airflow disturbances and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in aligned tube arrays, serious dust accumulation occurs on all tubes except those in the first row.

(1) Affected by the temperature of the heating surface, when this temperature is too low, water vapor or sulfuric acid vapor in the flue gas condenses on the heating surface, causing the fly ash to stick to it； (2) Influence of flue gas flow velocity ； If the flue gas flow rate is too low, ash buildup on the heating surfaces can easily occur; however, if the flow rate is too high, severe wear on the heating surfaces takes place ； (3) Effect of fly ash particle size: The smaller the fly ash particles, the larger their relative surface area, which means they are more easily adsorbed onto metal surfaces ； (4) Influence of airflow conditions and tube arrangement: As the velocity increases, airflow disturbances become more severe in offset tube bundles, and the loose dust accumulated on the tubes is easily blown away. The smaller the longitudinal spacing between the offset tubes, the greater the airflow disturbances and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in in-line tube bundles, serious dust accumulation occurs on all tubes except those in the first row.

Answer: The factors that affect ash deposition on the heating surfaces of boilers are as follows: (1) Influence of the temperature of the heating surfaces: When the temperature of these surfaces is too low, water vapor or sulfuric acid vapor in the flue gas condenses on the heating surfaces, causing the fly ash to stick to them. ⑵ Effect of flue gas velocity: If the flue gas velocity is too low, ash deposition on the heated surfaces can easily occur; however, if the velocity is too high, severe wear on these surfaces takes place. ⑶ Effect of fly ash particle size: The smaller the fly ash particles, the greater their relative surface area, which makes them more susceptible to adsorption on metal surfaces. ⑷ Effects of airflow conditions and tube arrangement: As the velocity increases, the airflow disturbances in a staggered tube bundle increase, and the loose dust accumulation on the tubes is more likely to be blown away. The smaller the longitudinal spacing between the staggered tubes, the greater the airflow vibrations and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in a aligned tube bundle, severe dust accumulation occurs on all tubes except those in the first row.

1) Affected by the temperature of the heating surface, when this temperature is too low, water vapor or sulfuric acid vapor in the flue gas condenses on the heating surface, causing the fly ash to stick to it. 2) Influence of flue gas velocity ； If the flue gas velocity is too low, ash buildup on the heating surfaces is likely to occur; however, if the velocity is too high, severe wear on the heating surfaces takes place. 3) Effect of fly ash particle size: The smaller the fly ash particles, the larger their relative surface area, which makes them more susceptible to adsorption on metal surfaces. 4) Influence of airflow conditions and tube arrangement: As the velocity increases, the airflow disturbance in a staggered tube bundle becomes greater, and the loose dust accumulated on the tubes is more likely to be blown away. The smaller the longitudinal spacing between the staggered tubes, the greater the airflow disturbance and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in a aligned tube bundle, severe dust accumulation occurs on all tubes except those in the first row.

1. Affected by the temperature of the heating surface, when this temperature is too low, water vapor or sulfuric acid vapor in the flue gas condenses on the heating surface, causing the fly ash to stick to it. 2. Influence of flue gas velocity ； If the flue gas velocity is too low, ash buildup on the heating surfaces is likely to occur; however, if the velocity is too high, severe wear on the heating surfaces takes place. 3. Influence of fly ash particle size: The smaller the fly ash particles, the greater their relative surface area, which makes them more susceptible to adsorption on metal surfaces. 4. Influence of airflow conditions and tube arrangement: As the velocity increases, airflow disturbances become more severe in staggered tube arrays, and the loose dust accumulation on the tubes is easily blown away. The smaller the longitudinal spacing between the staggered tubes, the greater the airflow disturbances and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in aligned tube arrays, serious dust accumulation occurs on all tubes except those in the first row. 1# zgj2405

Factors affecting ash deposition on the heating surfaces of boilers include: (1) The influence of heating surface temperature: When the temperature of the heating surfaces is too low, water vapor or sulfuric acid vapor in the flue gas condenses on these surfaces, causing the fly ash to adhere to them. ⑵ Effect of flue gas velocity: If the flue gas velocity is too low, ash deposition on the heated surfaces can easily occur; however, if the velocity is too high, severe wear on these surfaces takes place. ⑶ Effect of fly ash particle size: The smaller the fly ash particles, the greater their relative surface area, which makes them more susceptible to adsorption on metal surfaces. ⑷ Effects of airflow conditions and tube arrangement: As the velocity increases, the airflow disturbances in a staggered tube bundle increase, and the loose dust accumulation on the tubes is more likely to be blown away. The smaller the longitudinal spacing between the staggered tubes, the greater the airflow vibrations and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in a aligned tube bundle, severe dust accumulation occurs on all tubes except those in the first row.

There are many factors that affect ash accumulation in boilers, the most important of which are: 1. Flue gas flow rate – the lower the flow rate, the easier it is for ash to accumulate； 2. The properties of the ash itself: varying components in coal result in different amounts of ash accumulation. 3. The smoothness of the heating surface itself: the smoother the surface, the less likely it is to accumulate dust; the more dust that has accumulated on a heating surface, the greater the amount of dust there will be.

⑴ Effect of the heating surface temperature: When the temperature of the heating surface is too low, water vapor or sulfuric acid vapor in the flue gas condenses on the heating surface, causing the fly ash to stick to it. ⑵ Effect of flue gas velocity: If the flue gas velocity is too low, ash deposition on the heated surfaces can easily occur; however, if the velocity is too high, severe wear on these surfaces takes place. ⑶ Effect of fly ash particle size: The smaller the fly ash particles, the greater their relative surface area, which makes them more susceptible to adsorption on metal surfaces. ⑷ Effects of airflow conditions and tube arrangement: As the velocity increases, the airflow disturbances in a staggered tube bundle increase, and the loose dust accumulation on the tubes is more likely to be blown away. The smaller the longitudinal spacing between the staggered tubes, the greater the airflow vibrations and the stronger the scouring effect by the airflow, resulting in less dust accumulation on the tubes. In contrast, in a aligned tube bundle, severe dust accumulation occurs on all tubes except those in the first row.