The proper choice of chemicals for steam production water(1)

                  The proper choice of chemicals for steam production water(1)

The water used for steam production (boiler feedwater) requires the addition of chemicals, mainly to prevent scaling, corrosion, and ensure the quality of steam. The specific medication to be added usually depends on whether the equipment is a traditional "boiler" or a popular "steam generator", as well as the requirements for steam purity.    

Generally speaking, commonly used drugs are mainly divided into the following categories:

1. Core treatment agents (anti scaling and regulation)

This is the most basic dosing process, mainly used to prevent scale formation and regulate the acidity and alkalinity of water.      

Trisodium phosphate (Na₃PO₄): This is one of the most commonly used pharmaceuticals. Its main function is to react with calcium and magnesium ions in water, generating insoluble precipitates (water slag), which are then discharged through sewage to prevent hard scale from adhering to the furnace wall. It can also make existing sulfate or carbonate scale loose and fall off.      

Sodium carbonate (Na₂CO₃): commonly known as soda ash. It is mainly used to remove calcium hardness from feedwater, partially hydrolyze into sodium hydroxide at high temperatures in boilers, maintain the alkalinity of boiler water, and prevent acidic corrosion.

Sodium hydroxide can maintain the alkalinity of boiler water and prevent acidic corrosion

Sodium hydroxide (NaOH): commonly known as caustic soda. Mainly used to eliminate magnesium hardness in water and maintain the alkaline environment of boiler water. However, for steam generators or occasions with high requirements for steam quality, use with great caution, because excessive addition will lead to high alkalinity of boiler water, which will cause steam and water co rising (more foam), and even lead to "alkali embrittlement" (caustic embrittlement) of metals.

2. Auxiliary and composite agents (to enhance effectiveness and compatibility)

In order to adapt to different water qualities (such as high hardness or high alkalinity water), composite formulas or auxiliary agents are usually used.

Organic polyphosphates/organic polycarboxylates: These belong to high molecular weight polymers and are often used as water quality stabilizers. They have good dispersibility, can prevent sediment from accumulating and scaling, are not easily hydrolyzed, have good stability, and are often used in combination with soda ash or phosphate salts

Sodium humate/tannin extract: These are natural organic extracts. They can serve as a mud and dirt conditioner, keeping the water residue suspended and less likely to adhere to the heated surface. Sodium humate can also help remove old scale, and its effect is usually better than that of tannin extract

Water quality stabilizer: a composite agent formulated for specific water quality (such as extremely high hardness or abnormal alkalinity), usually containing various components such as scale and corrosion inhibitors.

3. Medications for specific problems

If your system has special issues (such as severe corrosion or the use of condensate recovery), you may also need the following chemicals:

Chemical deoxidizer: used to remove dissolved oxygen from water and prevent oxygen from corroding boilers and pipelines. This is very important for extending the lifespan of equipment

Condensed water treatment agent: If the condensed water is recovered, due to its acidic nature (low pH), it is prone to acidic corrosion. It is necessary to add film-forming amine or neutralizing amine to increase the pH value and protect pipelines and heat exchangers.