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Reasons for and solutions to white-colored wastewater from boiler water systems. Yellow-colored wastewater from boiler water systems is common; red-colored wastewater is also common, as is black-colored wastewater. However, white-colored wastewater from boiler water systems is less common. Have you ever seen wastewater from a boiler system that is white in color? ▲Not long ago, I received a call from a customer who said that the wastewater discharged from his 40-ton biomass steam boiler was white in color with a reddish tint, and he asked what to do about it Further investigation into the reason for the sudden change in the water quality used in the user’s boiler revealed that the user’s only desalination equipment had failed. To ensure continuous production, the user used groundwater as a substitute for desalinated water to supply the boiler, thereby maintaining steam production for about 12 hours, until the desalination equipment could be repaired. ▲After increasing the drainage of water from the boiler over a period of 24 hours due to the use of well water, the color of the wastewater discharged was white with a reddish tint. The user increased the amount of wastewater drained from the boiler by another 2 days, but the white and reddish color of the wastewater did not improve. Upon observing the wastewater sample after it was left to settle, it was found to be generally white; the upper part of the sample consisted of a semi-transparent white liquid, while the lower part contained white granular solid precipitates. The pH level of the boiler water was measured to be around 7. Colleagues and fellow students, what do you think is the reason for the white color of the wastewater discharged from this user’s boiler water? How do you think this user should solve this problem? Regarding issues such as boiler corrosion and scaling, red-colored boiler drainage water, adjustment of the pH value of boiler feed water, red-colored boiler water, hardness in steam condensate water, pipe failures caused by boiler corrosion and scaling, corrosion in steam systems, excessive iron content in steam condensate water, yellow-colored steam condensate water, and online descaling techniques that allow continued operation of the boiler without shutdown, Yan Hui from Beijing University of Chemical Technology at I86OO475З86 is always available to discuss these issues, exchange experiences and insights. Students are also welcome to share new technologies related to boiler water treatment, while colleagues can share their experience in managing and using boiler equipment, so as to learn from each other in addressing various practical problems associated with boilers. Reasons for the white color of boiler wastewater and solutions 1. Reasons for the white color of boiler wastewater: The boiler is supplied with demineralized water produced by OR membrane reverse osmosis, which is quite pure. When the equipment used for producing this demineralized water was suddenly damaged, in order to maintain normal operation, high-hardness, high-alkalinity groundwater was used as a substitute for the demineralized water and directly fed into the boiler. Under the influence of temperature and pressure inside the boiler, bicarbonate ions react with calcium and magnesium ions to form white precipitates of calcium carbonate and magnesium hydroxide. This is the reason why the wastewater from the boiler appears white. 2. Solutions for the white color of wastewater discharged from boilers: If the wastewater is not discharged in a timely manner, white precipitates of calcium carbonate and magnesium hydroxide will accumulate on the heating surfaces of the boiler or in areas where water flow is slow, thereby forming scale. Calcium and magnesium scale reduces heat transfer efficiency, leading to a decrease in the boiler’s output and thermal efficiency. Fuel and energy consumption increases, and in areas where scaling is severe, there is a risk of tube overheating, creep deformation, and tube rupture; therefore, it is necessary to carry out frequent and large-scale blowdowns to replace the boiler water promptly. Due to the low pH value of 7 in the boiler wastewater, acidic corrosion occurs in the boiler, as evidenced by the white color of the wastewater along with a reddish tint. The reddish color is caused by iron ions, which are the end products of corrosion; therefore, it is necessary to address this acidic corrosion immediately by raising the pH value of the boiler water. At the same time, it is also necessary to remove the calcium and magnesium scale that has accumulated on the boiler’s heating surfaces or in areas where water flow is sluggish. This will completely eliminate the safety risk of tube overheating, creep deformation, and tube rupture in areas with thick scale buildup, thereby ensuring the boiler’s thermal efficiency and output. Colleagues and classmates, what do you think this user should do to solve this problem? Due to an unexpected issue with the user’s boiler, the formation of calcium and magnesium scale occurs over a short period of time, the affected area is limited, and no dense, hard scale has yet formed. Since this type of scale is in a slurry form, it is not necessary to shut down the boiler for descaling. My solution is to carry out frequent and large-volume water discharge operations, quickly replace the boiler water, and use a multi-functional, phosphorus-free anti-corrosion and descaling agent for 15 days to increase the pH level and alkalinity of the boiler water, thereby addressing the issues of corrosion and scale formation in an urgent manner. 3. The multi-functional phosphorus-free anti-corrosion and scale-removal agent boasts 10 technical advantages. This multi-functional phosphorus-free anti-corrosion and scale-removal agent is the core patented product of the zero-waste steam generation technology, which was awarded the Second Prize for Technical Invention in January 2008 as part of the project conducted by Beijing University of Chemical Technology on \"New technologies for material protection and research on chemical phase separation systems and their application in industrial boilers.\" It has 10 advantages: ① Anti-corrosion effect and formation of a protective film; corrosion inhibition rate ≥99%, scale inhibition rate ≥99%; wide range of scale inhibition effectiveness; phosphorus-free formula that replaces trisodium phosphate ； ②As a shutdown protection agent, it provides corrosion inhibition at a rate of ≥99% for protecting boiler and system equipment when they are not in use. It is sufficient to simply seal the boiler equipment after shutting it down, without the need for frequent regular inspections. There is no need to drain the boiler water either when starting up or shutting down the boiler. It is suitable for use in situations involving long-term shutdowns, frequent start-ups and shutdowns, as well as prolonged intermittent operation of the boiler ； ③. As a scale dispersant for rust removal and dispersing iron scale ； Especially suitable for boilers in which high-temperature steam condensate is reused directly without iron removal treatment ； ④Alkaline agents, used as pH regulators to raise the pH of feedwater and boiler water, to neutralize the weakly acidic corrosion caused by CO2, and as alternatives to sodium carbonate, sodium hydroxide, and ammonia ； ⑤It removes scale and deposits, as well as old scale through chelation; it replaces the need for acid cleaning of boilers, enabling damage-free online cleaning of boilers so that they can continue to operate without having to be shut down ； The steam generator eliminates the need for regular deep cleaning; there is no requirement to carry out periodic deep chemical cleaning to remove scale and prevent corrosion every six months or quarterly, which would otherwise damage the steam generator and shorten its service life ； ⑥. Acts as an antifoaming agent to increase steam dryness and ensure steam quality ； ⑦Raw water + multi-functional phosphorus-free corrosion and scale inhibitor; hot water boilers can use this instead of softened water, along with deoxygenation procedures to protect the environment ； ⑧Raw water + multi-functional phosphorus-free corrosion and scale inhibition agent + iron removal and corrosion protection agent for steam condensate, replacing the softening device, deaeration equipment, and iron removal equipment in steam boiler systems ； ⑨. Simple operation: Add the chemical to the make-up water tank; a pH value of 10.5–12 for the water in the boiler is considered acceptable ； ⑩The chelating, dispersing, and lattice-distorting effects on scale are all non-stoichiometric and exhibit a threshold effect; a low dosage of the additive is sufficient to reduce the boiler’s blowdown rate. 4. Postscript: Thanks to the user’s timely measures to treat the quality of the boiler water, by the 7th day the appearance of the wastewater samples from the boiler water had returned to normal, being clear and transparent; even the usual yellowish color of the boiler water was gone. The reason for this was that the user used NaOH to adjust the pH value of the boiler water, thereby preventing acidic corrosion and instability in the water. Thereafter, the user replaced sodium hydroxide and trisodium phosphate with a multi-functional phosphorus-free anti-corrosion and descaling agent to address corrosion as well as scaling issues; to date, the boiler is performing well, maintaining high thermal efficiency. Reasons for the white color of wastewater from boiler water and solutions (Yan Hui)