The sodium ion level in the boiler drum water is above the limit

My suggestions, hehe: 1. Check if there are any issues with the row spacing and column spacing. 2. Verify whether sampling is done correctly

Excessive sodium ions are generally related to the quality of the boiler water; it may be due to inadequate waste discharge. Boiler waste discharge occurs in two forms: continuous discharge and periodic discharge. Continuous drainage, also known as surface drainage, involves the continuous removal of a portion of the boiler water from the area where the salt and alkali concentrations are highest, in order to reduce the levels of salts, alkalis, silicic acid, as well as suspended solids in the boiler water. Therefore, the continuous drainage pipes are installed at a depth of 80–100 mm below the normal water level. Periodic drainage is used primarily to remove deposits such as sludge and dirt from within the boiler, and thus its drainage outlets are usually located at the bottom of the boiler drum and at the bottom of the header. While checking the sewage discharge system, conduct a comprehensive analysis of the deionized water to see if the water quality is the cause!

It is recommended to take samples from each water stream entering the boiler for separate analysis

Excessive sodium ions should cause chemical corrosion of the air pocket. It is recommended to first check the water intake to ensure it is of satisfactory quality. 2. Check the return water condition to ensure that it does not exceed the specified limits. 3. Check the drainage situation; regular drainage can create a turbulent flow of water, which helps to remove ions to the greatest extent possible.

This post was last edited by zgj2405 on 2011-12-29 21:39. The concepts of continuous discharge (as mentioned in points 2 and 3) and intermittent discharge (referring to periodic discharge) are not necessarily the root cause of the problem. In particular, the so-called \"inter-row\" arrangement should not be the cause of the problem (it can only discharge the sediment at the bottom of the boiler). 　　The steam-water separator located at the top of the drum has fallen off, and it is certain that the steam escaping from the boiler’s water surface contains corrosive substances. It is usually caused by sodium corrosion. The poster said that “the sodium ion levels often exceed the limit in sampling analyses,” which probably refers to an excess of sodium ions in the steam samples. This is because: only once-through boilers require testing the sodium ion content in the feedwater (which should be ≤10μg/L). However, it is required that the quality of steam be tested for all power generation boilers. Therefore, the boiler referred to by the poster is likely the drum-type boiler used for power generation in his facility, where the sodium ion content in the steam is above the permissible level. 　　There are two reasons for the excessive sodium ions in the steam. One reason is the high sodium ion content in the boiler water (which is related to poor feedwater quality and low continuous blowdown rates). Another reason is related to the high water level during boiler operation, which leads to severe water entrainment in the steam (mechanical carrying) and even foaming and bumping problems in the boiler. 　　Back to the topic. Generally speaking, in a drum boiler with proper design, as long as the water level in the boiler does not exceed the maximum control level, it will not result in an excessive ion content in the steam. As long as the water quality in the boiler is of proper standard, foam boiling problems will not occur. Therefore, the unit where the poster works should ensure good quality of the boiler feed water, maintain proper boiler water levels, and carry out proper analysis and control of the quality of the boiler water and steam (continuous blowdown can be used to control the quality of the boiler water in this regard). This will help prevent problems such as mechanical entrainment and foaming, and it should also allow avoidance of abnormal conditions like excessive sodium ions in the steam and corrosion of the components at the top of the steam drum. 　　If this issue still cannot be resolved, then there is a problem with the boiler’s design – specifically, the boiler’s drum is too small, and the highest water level is too close to the steam-water separator! 　　Could the original poster tell me the name of your organization, the specifications and model of the boiler, as well as the manufacturer? If possible, please attach the general boiler diagram and the drum drawing so that I can assess whether there are any issues with its design. 　　

Sorry, I typed it wrong; I should say thank you to everyone! ! ! ! ! :lol

The water ion exchange equipment should be inspected; the sodium content can be removed from the ion exchange resin. Using mixed-bed treatment can help reduce the sodium level. It is directly related to the reduction of sodium ions in the steam in the subsequent stage

Excessive sodium ions can cause caustic embrittlement. Especially in tiny gaps, such as at the joints between the tube sheet and the tubes, although gasketing is used there, issues related to manufacturing processes and operator skills often result in the presence of such small gaps. When water turns into steam, the impurities contained in the water remain behind. If there is a high level of sodium in the boiler water, this sodium will accumulate in those gaps and combine with the OH ions in the water to form alkalis. This is the mechanism behind caustic embrittlement. Both the sewage discharge system and the ion exchanger need to be checked.

I’ve learned it! By the way, I have a question for everyone: during the normal operation of a boiler, isn’t it necessary to add Na3PO4 to the water? Shouldn’t there be more sodium ions then? It has nothing to do with the sodium content in deionized water, right?