【Q&A Question 095】2016.07.24
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【Q&A Question 095】July 24, 2016: What are the purposes of the two methods used for draining waste from the drum? The answer key can be seen after responding; scoring is based on identifying the key points. Drainage from the steam drum can be divided into periodic drainage and continuous drainage based on the operation time. Scheduled discharge means removing the sludge and dirt accumulated at the bottom of the boiler at regular intervals. It enables uniform concentration of the drum water, which helps to improve the quality of steam. Stranding is done to prevent excessive salt and sulfur content in the boiler water, while blowdown is typically carried out at the points where the concentration of boiler water is highest.
The purpose of continuous drainage is to continuously remove the dissolved salts in the boiler water. The purpose of regular blowdown is to periodically remove the sediments (slag) from the boiler water. Depending on their purpose, they are installed in different locations; the series ones are usually placed near the evaporation surface of the drum. The fixed drain is generally located at the lowest part of the evaporation equipment.
Timed blowdown: Remove sediment from boiler water; Continuous blowdown: Control salt content
1) Drum blowdown is used to adjust water quality and improve heat transfer efficiency. 2) Intermittent discharge refers to the drainage drains at the bottom of the waste boiler and the bottom of the drum; it is primarily used to remove the sediment that has accumulated there. 3) Continuous drainage refers to the discharge pipe taken from the middle of the drum, which is primarily used to remove debris floating on the surface of the boiler water.
Continuous discharge and periodic discharge. Continuous discharge is used to remove the free impurities in the steam drum. Regular sewage discharge can remove free impurities as well as those settled at the bottom of the steam drum.
Answer: Drum blowdown can be divided into intermittent blowdown and continuous blowdown based on the operation time. Intermittent blowdown, also known as periodic blowdown, involves removing the sludge and dirt accumulated at the bottom of the boiler at regular intervals. This process is typically carried out every 8 to 24 hours, with each blowdown lasting between 0.5 and 1 minute; the blowdown rate should be no less than 1%. It is better to carry out intermittent blowdown frequently and over short periods, as this helps to achieve a uniform concentration of water in the steam drum, thereby improving the quality of the steam. Continuous blowdown refers to the continuous discharge of concentrated boiler water, with the main purpose of preventing excessive salt and sulfur content in the boiler water. The blowdown points are usually located where the concentration of boiler water is highest, that is, 200–300 mm below the water level in the drum. The continuous blowdown rate is usually adjusted based on the water quality analysis parameters of the drum water.
1. Periodic drainage to remove deposits at the bottom of the steam drum; 2. Continuous drainage to remove floc in the middle section
Drainage from the steam drum can be divided into intermittent drainage and continuous drainage based on the operation time. 1. Intermittent blowdown, also known as periodic blowdown, involves removing the sludge and dirt accumulated at the bottom of the boiler at regular intervals. This process is typically carried out every 8–24 hours, for a duration of 0.5–1 minute each time; the blowdown rate should be no less than 1%. It is better to carry out intermittent blowdown frequently and over short periods, as this helps to achieve a uniform concentration of water in the steam drum, thereby improving the quality of the steam. 2. Continuous blowdown refers to the continuous discharge of concentrated boiler water, with the main purpose being to prevent excessive salt and sulfur content in the boiler water. The blowdown points are usually located where the concentration of boiler water is highest, that is, 200–300 mm below the water level in the drum. The continuous blowdown rate is usually adjusted based on the water quality analysis parameters of the drum water.
Continuous discharge deals with impurities in the water meter, while periodic discharge deals with impurities at the bottom
The blowdown methods for drum boilers can be divided into continuous blowdown and periodic blowdown. Continuous discharge involves the continuous removal of boiler water from the drum. The purpose of continuous drainage is to prevent excessive salt and silicon levels in the boiler water, as this can affect the quality of the steam; it also helps to remove any fine or suspended sediment. Therefore, the continuous discharge point should be located in the section of the boiler water with a higher salt content, in order to reduce the amount of waste discharged and improve the efficiency of discharge. The purpose of regular slag discharge is to remove sludge, which accumulates mostly at the bottom of the water circulation system; therefore, the discharge point should be located at the bottom of this system, such as at the lower header of the water wall. Regular slag discharge is best carried out when the boiler is operating at low load, as sludge tends to accumulate at this time. The interval between waste discharge operations is determined by the quality of the boiler water: if there is a large amount of sludge, the interval is shorter ； Otherwise, the interval is long. The duration of each discharge is generally no more than 0.5 to 1.0 minute. The opening degree of the continuous discharge valve can be determined based on the quality of the boiler water. For boilers fed with demineralized water, the blowdown rate can be determined based on the silicon content in the feedwater, boiler water, and steam