Soft water device in front of the boiler

It depends on the type of boiler you have. For small saturated steam boilers, a sodium ion softener with one unit in use and one as a backup is generally sufficient. For larger boilers, around 10 tons in capacity, a three-tank water supply system is a good option. If it is a power plant boiler, then a professional chemical water treatment system is necessary.

The second floor explained how to select an appropriate boiler water softening system; now let’s discuss the principles of boiler water treatment. 1. Working principle of boiler water treatment equipment in the water industry: Since water hardness is mainly determined by calcium and magnesium, cation exchange resins (water softeners) are generally used to displace Ca2+ and Mg2+ from the water – these ions being the main components that cause scale formation. As the amount of Ca2+ and Mg2+ in the resin increases, its ability to remove these ions gradually declines. Once the resin has absorbed a certain amount of calcium and magnesium ions, it needs to be regenerated. The regeneration process involves flushing the resin layer with brine from a salt tank, thereby displacing the hard water ions from the resin; these ions are then removed along with the wastewater from the tank, allowing the resin to regain its softening and exchange capabilities. 　　Since water hardness is primarily caused by calcium and magnesium, the principle of softening water through sodium ion exchange involves passing raw water through sodium-type cation exchange resin, thereby allowing the hardness-causing ions Ca2+ and Mg2+ in the water to be exchanged for Na+ in the resin; this process adsorbs Ca2+ and Mg2+ from the water, resulting in its softening. Chemical equations for boiler water treatment equipment:
Removal of calcium:　　 CaCO3 + 2NaCl = CaCl2 + Na2CO3
Removal of magnesium:　 MgCO3 + 2NaCl = MgCl2 + Na2CO3

2. Operating conditions for boiler water treatment equipment:
1) Requirements regarding water pressure, temperature, and quality entering the exchanger:
(1) Water pressure: 0.2–0.5 MPa
(2) Water temperature: 5–45°C
(3) Suspended solids: <5 mg/L during forward-flow regeneration ； Counterflow regeneration and floating bed: <2mg/L (4) Total hardness: Grade 1 sodium <6.5mmol/L ； Secondary sodium level: <10 mmol/L 　　(5) Free chlorine: <0.3 mg/L 　　(6) Iron content: <0.3 mg/L 　　(7) Oxygen demand (CODMn): <2 mg/L(O2) 　　 2) Requirements for working environment temperature and humidity: 　　(1) Ambient temperature: 5–50°C 　　(2) Relative humidity: <95% (at 25°C) 　　 3) Power supply: AC 220V ±22V/50Hz or 380V ±38V/50Hz. Key points for the construction and installation of boiler water treatment equipment: 1) Pipes should be equipped with supporting structures to prevent stress on control valves. 　　 2) When the inlet pipe of the water softener is connected to the domestic water supply pipeline, a backflow preventer must be installed on the inlet pipe. 3) If the inlet water pressure is below 0.15 MPa, pressure-boosting measures must be taken. 4) The length of the sewage pipe should be less than 6 m ； No valves installed on the pipe ； The outlet should not be higher than the valve body, with an open end to prevent siphoning. 　　 5) Except for water softeners that use hydraulically driven multi-way valves, a 220V power supply is required on site. 　　 6) Iodized salt should not be used; calcium-added salt should be used as a regenerating agent.

For small boilers, water treatment is relatively simple and the equipment is straightforward. Medium-pressure boilers require higher standards for water quality; the water used must be demineralized water, and the relevant equipment includes multi-media filters, activated carbon filters, reverse osmosis systems, and safety filters.

What material is generally best for the valves in soft water pipes?