Top ten common problems in boiler water treatment, have you encountered it?

Boilers can be safe, economic, reliable and stable operation, as well as the output of qualified steam or hot water, familiar with the boiler water, understand the dangers of poor water quality on the boiler, master the water and steam quality standards, good boiler water treatment and the necessary chemical treatment in the furnace, and in operation in strict accordance with the standard requirements for supervision of water and steam quality, to ensure that the boiler water quality and steam quality and boiler safety and economic operation is extremely important.

The purpose of boiler water treatment is to remove impurities that are harmful to the boiler, prevent boiler scaling and corrosion, ensure good steam quality, ensure the safe and economic operation of the boiler, while achieving the purpose of energy saving and energy conservation.

Boiler water treatment mainly includes scaling water treatment, make-up water (boiler supplemental water) treatment, condensate (turbine condensate or process recovery of condensate) treatment, feed water de-oxygenation, feed water ammonia and pot dosing treatment in five parts.

1. Scaling water treatment

What should be done to treat severe boiler water scaling? If not treated in time, some problems can easily occur. Before the scale treatment, to understand the causes of scaling: boiler in the process of continuous water supply, continuous evaporation, the salts contained in the pot constantly stay, pure water into steam sent out of the furnace, and the remaining furnace water salt concentration is constantly rising, concentrated, so that the degree of salt in the furnace water reaches saturation or even supersaturation, the salts will be precipitated from the water, generating precipitates. These precipitates, part of which is bonded in the heating strength of the heating surface, the formation of hard scale. 

The formation of scale will seriously threaten the safety of the boiler, the operation of process equipment, boiler life, etc.. In addition, it will have a corrosive effect on the equipment, making the furnace wall brittle. If these problems are not taken in time to deal with effective methods, the consequences will be very serious. Therefore, in normal times, we should pay attention to. 

Boiler corrosion and scale inhibitor has a high corrosion and scale inhibition performance, its temperature resistance is particularly good, can be effectively applied to low-pressure boilers in the furnace scale water treatment. Boilers include water heating, steam, locomotive boilers, etc. Boiler corrosion and scale inhibition agent can also be used for desalination, distillation and automotive water tank system corrosion and scale inhibition.

2. Make-up water treatment

Due to the steam use (heating or power generation) and the degree of condensate recovery, the amount of make-up water in the boiler varies. Condensing power plant boilers are generally less than 3% of the evaporation of the make-up water, heating boilers can be up to 100% of the make-up water. Feed water treatment process: 1) pretreatment 2) softening 3) desalination.

3. Condensate treatment

Condensate in the process of circulation, will be subject to the turbine condenser cooling water leakage and system corrosion products caused by pollution, and sometimes need to be treated. The amount of condensate treatment with the boiler parameters, furnace type (such as with or without a pot or separator) and condensate pollution wishes. As the boiler parameters improve, the amount of condensate treatment generally increases gradually. Supercritical pressure boilers should be fully processed; ultra-high-pressure and subcritical pressure boilers for 25% to 100% of the amount of treatment; boilers below high pressure with a pot generally do not deal with. Commonly used condensate treatment equipment are cellulose covered filters and electromagnetic filters. Condensate in which the removal of corrosion products (copper oxide and iron oxide, etc.), and then into the mixed bed or powder resin covered filter for deep desalination.

4. Feedwater oxygen removal

Dissolved oxygen in the boiler feedwater can corrode the metals of the thermal system. Corrosion products in the boiler heat load at higher levels of copper and iron scale, so that heat transfer deteriorates, or even cause a burst tube or deposition in the turbine high-pressure cylinder, so that the turbine efficiency is reduced. Therefore, after softening or desalination of the feed water and condensate, before entering the boiler is generally de-oxygenated. Commonly used oxygen removal methods are thermal oxygen removal and vacuum oxygen removal, and sometimes supplemented by chemical oxygen removal.

5. Feed water with ammonia and pot dosing treatment

After the make-up water treatment, condensate treatment and feed water de-oxygenation of the boiler feed water, generally require the addition of ammonia or organic amines to improve the pH of the feed water, to prevent corrosion of acidic water on metal parts. Boilers with pot barrels are generally required to be treated in the pot. When processing, trisodium phosphate or other chemicals are added to the pot barrel to turn the salt impurities in the water that can form scale into sludge that can be discharged in the discharge to prevent or slow down the formation of scale.
Boiler water treatment daily work.

1) Boiler scale prevention

Water boils and evaporates after being heated in the pot, providing conditions for chemical reaction and continuous concentration of impurities in the water. When these impurities in the pot water reaches saturation, there will be solids precipitation. The solids precipitated, if suspended in the pot of water, known as water slag; if deposited on the heating surface, known as scale.

Boiler operation, in order to prevent the generation of scale and its adhesion, to ensure the safe and economic operation of boiler equipment, need to strengthen the boiler water treatment, to ensure that the boiler feed water in line with the feed water quality standards; strengthen the management of pot treatment, to ensure that the pot water quality in line with the pot water quality standards; strengthen the boiler operation management, to ensure that the boiler is running without scale, without deposits. Reasonable drainage, timely exclusion of water slag.

2) Boiler anti-corrosion

Metal components broken, coal conservator, water belt wall, convection tube bundle and pot barrel and other components will be caused by poor water quality and corrosion. Boiler corrosion includes the protection of operating boiler corrosion and decommissioning period. For boilers with deaerating devices, the main supervision of the deaerating device deaerating effect.

3) Vapor supervision

When the boiler is in operation, chemical analysis of the feed water, pot water and steam of the boiler is carried out according to the national standards to check whether the quality of the steam meets the requirements.

4) Chemical cleaning

Cleaning of boilers includes two types of new boilers and operating boilers. For industrial boilers, the new boiler chemical cleaning is mainly boiled to remove the dust and oil accumulation in the barrel and furnace tube.