What is the effect of adding deoxidizers to the deaerator for the feed water of the waste heat boiler?
Thread Content
Our factory wants to use chemical agents to deoxidize the water in the deaerator. Since I haven’t used it before, I’m going to see if any other manufacturers have used it and how the results were. Are there many impurities formed by chemical deoxygenation? If the feedwater temperature is low, will the heat exchange efficiency of the waste heat boiler be good? I believe that the level of feedwater temperature in the waste heat boiler only affects the amount of steam generated by the boiler, and it has no impact on the boiler’s heat exchange capacity. Let’s discuss it together.
Chemical deoxygenation: This method involves using certain chemical agents that readily react with oxygen, causing a chemical reaction with the oxygen dissolved in water to produce substances that do not cause corrosion to metals, thereby achieving deoxygenation. Chemical deoxygenation can only completely remove oxygen from water, but not other gases; moreover, the oxides formed increase the content of soluble salts in the water.
Thermal deoxidation is generally used; what is the name of the chemical agent you use? Please explain its principle; we can discuss this further.
I haven’t used it either; there is a chemical agent for removing oxidation called a “deoxidizer”. As far as I know, the chemical should be added to the deaerator for deoxygenation. Convert the oxygen in the deaerator water into certain salt compounds, and then remove these substances through waste discharge.
We have TD series low-temperature feedwater deoxidizers; different products are available for softened water and demineralized water as feedwater. These deoxidizers provide excellent deoxidation effects when the feedwater temperature is above 30 degrees Celsius, and they can reduce the dissolved oxygen level in the feedwater to below 50 micrograms per liter. The deoxidizers are of the fully organic volatile type, so they do not affect the salt content in the feedwater or boiler water. Another new type of product is an organic hydroxylamine, lime-based, and phosphorus-based composite deoxygenant; the deoxygenation products are ammonia vapor and trisodium phosphate. This product can partially replace the use of ammonia in feedwater treatment as well as trisodium compounds for scale prevention in boilers, allowing for multiple functions with a single product. Several boilers in our factory have been in use for over three years with this product. Feel free to contact us at 13939058587 or 13939028952
The principle of chemical deoxygenation is to use reducing chemical agents to react with the oxygen in water, thereby consuming the dissolved oxygen. If chemical deoxygenation is used alone, a large amount of these chemical agents will be required; it is therefore recommended to first carry out thermal deoxygenation and then use chemical deoxygenation as a supplementary method. Thermal deaeration requires maintaining the appropriate deaeration temperature; otherwise, the deaeration effect will be poor. It is preferable to use organic chemical deoxidizers; salts will increase the salinity of boiler water.
There is experience in using low-temperature chemical deoxidizers for 25 t/h medium and low-pressure CFB boilers. Personally, I don’t think it’s a good option: the convective tube bundle has tubes running from the inside outward (resulting in unstable deoxygenation) ； The economizer is leaking from the bottom up (decreasing flue gas temperature, dew point corrosion). This thing is also expensive; its deoxygenation efficiency doesn’t increase in proportion to the amount used, and it’s more costly than using a thermal deaerator (don’t rely on its project reports, as they usually don’t take into account the enthalpy of the hot water output from the thermal deaerator). I firmly resist using it, and I’ve basically broken off relations with the merchants and certain colleagues. (The reason is obvious to everyone)