【Goal of the treatment】
The boiler is the factory heart, good water quality treatment can prevent boiler scale deposition, the boiler corrosion and the priming question, avoids the boiler rupturing and the damage, lengthens the boiler life, and saves the energy, the reduced maintain, prevented nonessential shut down and production break down etc. , the factory should pay much attention to maintenance work.

 【Question and processing of the original water】
1.The boiler have question of boiler scale deposition, the corrosion, the priming, ruptures etc., the reason is in the original water have impurity (Impurity), therefore original water have to process before use.

2.In the original water may harms the boiler item (including suspension impurity, dissolved solid, dissolved gas three kinds):

Suspension impurities懸浮雜質(S.S.)

Conductivity電導度(Conductivity)

Total hardness總硬度(T-H)

Alkali總鹼度(M-Alk)

Sulfating硫酸鹽(SO4)

Chlorine氯離子(Cl)

Silica acid矽酸鹽(SiO2)

Ferric鐵份(Fe)

Manganese錳(Mn)

Organic matter有機物

Microorganism微生物

Others其它(O2，CO2，H2S，H2SO4，NH3 etc.)

      3.General processing method (similar with waterworks processing method):
地下水groundwater（原水original water）→殺菌disinfect→氣曝air sunlight→沉澱precipitation→過濾filters→軟化softens→給水槽feed water tank→鍋爐boiler→製程procedures→回收水recycling water(→回到給水槽feed water tank)
Above steps whether necessary or not depend on original water good or not.

4.Chooses the good water source (water well or running water) is more economy than uses the bad water source. The running water after the choice and processing, conductivity, alkalinity, hardness, iron, manganese, organic matter will lower than groundwater, if the ground water quality no good consider uses the running water as far as possible.

5.When the new install boiler (specially is high load) choose the soft water, must text the water quality first then decide the size, avoid the boiler use water capacity over the soft water pick the water capacity, cause hardness of divulges, and boiler scale deposits and ruptures the tube

【Soft water question】

1.Importance of the soft water: In the water the calcium (Ca), the magnesium (Mg) the ion is called hardness (Hardness), after heats up will produce boiler scale as following:

 Mg+2  +  SiO3-2  →  MgSiO3↓                        ｝ Silicates hard filthy
　

2.Computation of boiler scale: For example hardness of feed water 300ppm, used 10ton water per day：

300ppm ×10ton/Day ×1000kg/ton ×10-6/ppm

＝3kg/Day＝90kg/Month＝1080kg/Year

     Some of above boiler scale will blow down (Blow down) along with the bottom to outside boiler but boiler harm can be imagined. Adds the liquid maybe solve the partial problem, but if the hardness over high, adds the liquid is uneconomical (needs too much), and not effect, so install the water softener, and completes the soft water is better.

3.The water softener regeneration picks the water capacity, it can estimate for following formula：
The hardness of original water (ppm) * picks the water capacity (Ton/) = the exchange capacity (40 g/L) * the resin quantity (L)

4.Water softener regeneration operation：
After uses the water softener resin exchange capacity, need 10% salt water regeneration to restores the exchange capacity. Its regeneration step is as follows：

(1)Counter washes: The water from the water softener bottom counter current on, the inflation becomes less crowded resin of bed by the compression, and will filter upper impurity and the resin detritus discharges outside the tower, counter wash time approximately 10~15 minute.

(2)Rest: After counter washes the resin, lets it subside naturally about 5 minute

(3)Salt washes: By concentrated brine through the resin tower, the salt water passes over while discharges, about 20~30 minute. By restores the resin the reproductive property. Each liter resin approximately uses table salt of the 0.1kg (NaCl), compounds 10% salt water, the proportion approximately 1.07335.

(4)Mortgages: By the time salt water flow speedy equal to original water of slow speed through the resin axis, remain the concentrated salinity water to discharge outside the tower, about 15~20 minute.

(5)Clean: When picks water the original water speed of flow, through the resin bed, and continue to remain the salt water completely to discharge outside the tower until no hardness, it needs about 15~20 minute. Only equipment combine with mortgage and clean for clean steps, the time approximately 30~40 minute.
　

5.Inspect soft water：

(1)Method: Takes 20 ~30c.c. water and drips into the EBT hardness indicator for 1-2 drop, the water appear the blue color for normally have no hardness, appear the red is has hardness to be regenerate immediately, appear the purple that mean close picks the water end point or the water softener, the resin possibly has the problem.

(2)Main point：

A、The water softener outlet and the feed water tank all needs to test, especially feed water tank.

B、In front of the end point takes a sample, test is best.

C、The boiler operator soft water must down well, each shift or every day should use the EBT hardness indicator examination and fill in the record, avoid the boiler ruptures the tube.

D、Has boiler scale the deposition to cause boiler of the broken tube recording, each shift or every day must examine the soft water whether normal, and review the water softener regeneration frequency and the equipment size whether enough.

6. Soft water makes not good possible reason

(1)The water softener picks the water capacity too small or the water source become difference.

(2)Over picks water end point and not to regenerate, regeneration period is too long.

(3)Adds the salt not on time, salt tank cause the salt bridge, and filters hole to stop up.

(4)The resin surface (Coating) or poisoned and disruption, the efficiency reduces or expires: Decision: The resin from golden change to sorrel and the color non-uniformity, the resin disruption.

When resin (Coating) slight can use cleaning agent wash it, if it serious must replace. The resin uses over a year have to examine once, specially the ground water, every year should supplement 5~10%.

(5)Mechanical failure, powers cut and so on.

【Boiler water treatment】

1.Middle low-pressure boiler water quality control standard (please refer to CNS, JIS, ASTM standard)：

A、SW(Soft  water)：

B、BW(Boiler  water)：

C、CD(Condensate)：

2.Boiler scale of deposition barrier and the processing method：

(1)Cause boiler scale reason: As front states.

(2)Boiler scale creates the boiler barrier:  
    -> Hinders the hot conduction.
    ->Reduces the efficiency and increase oil cost.
    -> Creates need to acid washing, the danger and the harm.
    -> Creates ruptures the tube, shutdown, maintain.

(3)Determine：

A、The water softener outlet water sample use the EBT hardness indicator test show red.

B、Discharges the boiler water turbid, if the boiler sludge is many that mean soft water make is not good, has boiler scale deposition, and show that boiler has ruptures danger of the tube, should improvement soft water make soon and increase dose amount.

(4)Internal treatment additive treatment：

Function of phosphate is combine hardness become the insoluble slime：

3Ca+2    +   2PO4-3   →   Ca3(PO4)2

3Mg+2   +   2PO4-3   →   Mg3(PO4)2

By CMC, SSP, PMA, Lignin etc. strong dispersant to disperse the suspension boiler sludge in boiler water, through the bottom discharges to out of boiler, like figure 1

(5)Amount: about 20~50ppm, depend on the original water quality and the boiler size, if the hardness of water increase to 5ppm, the internal treatment additive amount must double, however soft water is important.

(6)Control: PO4 20~40ppm

Figure 1: The calcium carbonate (CaCO3) scale the crystallization after disperses with high polymer dispersant crystallizes bears twists, comparison figure of suppressed growth.

3.Corrosion problem and processing

(1)Corrosion origin：In the water dissolves oxygen will have the oxidizing reaction with metal in the high temperature, chemical reaction formula is:

(2)Harm：

A、Damage boiler: The corrosion from pitting or grooving will harm boiler very big.

B、Oxide compound deposition: Cause the hot conduction obstacle and reduces efficiency etc.

(3)Function of oxygen scavenger：

2Na2SO3  ＋  O2      2Na2SO4

N2H4        ＋  O2      N2↑   ＋   2H2O

Explained：
a.Sodium sulfite is powdery, before use first must dissolve is not convenient, and the amount used quite big; hydrazine is the liquid, the amount used lower but the price is higher.
b.Sodium sulfite reaction is higher; the deoxidization is fast, especially under low temperature.
c.Hydrazine have toxicity, should carefully process, cannot use to the food products factory, sodium sulfite non-toxic, may use in the food products factory.
d.The oxygen scavenger best gives to the feed water tank, in order to have the enough time to deoxidization.

(4)Control：SO3       20∼40ppm

N2H4    0.1∼1.0ppm

Fe         ＜2∼4ppm

(5)If discharges the boiler water is turbid, that mean the boiler or the recycling water pipeline corrodes seriously, this time add oxygen scavenger and condensate treatment agent (neutralizing amine and so on) or boiler passivator treatment, it can rapid and effective solve corrosion rust problem.

(6)The recycling water pipeline corrodes the main reason is alkalinity in the boiler water, decomposes CO2, follow steam after evaporates the condensation in the recycling water, cause the acidity

corrosion, the reaction formula is:

CO3-2  +  H2O       CO2↑  ＋  2OH-

CO2  +  H2O      H2CO3      H+  ＋  HCO3-

May add condensate treatment agent to solve it.

4.The priming problem

(1)Phenomenon: Steam trap moves frequently, heating efficiency reduce, recycling water conductance 22#>>10mu S/cm. When boiler fluid position is unstable, and causes the boiler flame failure, the operation to be difficult.

(2)Harm: Waste energy, cause heating efficiency reduces and production bottleneck makes steam bumping and the pipeline trap block up.

(3)Origin:

A、Mechanical problem: The steam separator damages、block up or has not installed.

B、System regulation problem: System regulation steam amount used fluctuation oversized.

C、Water quality problem:

a、The boiler water concentrates too high, conductance >>10000μS/cm, total solid amount are too much.

b、The boiler water alkalinity too high causes the saponification.  

c、Feed water has grease.

d、Feed water organic has too much.

(4)Solves: Attention the boiler water blow down, and add some antifoam agent in the internal treatment additive, if necessity the boiler should change to continuous blow-down, or makes the simple continuous blow-down installment.

【Acid-washing and problem】
1.Acid-washing：

(1)Characteristic: Clean boiler scale rapid and effective. But it must shut down, and the work is more dangerous, if the acid-washing unsuitable, will cause the equipment to corrode and damage.

(2)Acid-washing decision: Put some boiler scale into acid liquor, if it has many bubbles that will easy to acid-washing.

(3)Acid-washing step: According to acid-washing step, or give it to has acid-washing experience boiler company.

(4)When acid-washing must add the corrosion inhibitor and complete neutralization and passivation processing to avoid the boiler corrode and damage.

2.Method of clean boiler scale in running: The scale remover:

(1)Characteristic: Contains the special Polymer dispersing agent, boiler scale strips agent, may clean scale in running.

(2)Usage: keep scale remover in the boiler water (100 ~ 150ppm) for several weeks, then boiler scale will clean away. Discharges the boiler water show cream color, the small sheet boiler scale will fall off.

(3)Amount used: The small boiler add about 0.5~2㎏every day, its amount about 1/4~1 doubles of internal treatment additive.

【Conclusion】

1. The boiler water treatment is very important, should specially respect, and appoints the specialist to be responsible.

2. Soft water has to check day and night, prevent hardness leak cause boiler scale deposition.

3. Boiler water should the full quantity discharge every day and inspection discharge water color, and add medicine normally.

4.should establish〝 the boiler water system management data sheet 〞, this records can help the management.

5.Water systems have the problem should solve immediately, if necessity, you should contact with water treatment company to solve.