Methods for cleaning boiler scale

As we all know, boilers are usually used to soften steel, especially in many factories. Boilers are divided into many types, some are small boilers, and some are large boilers. Because the pressure inside the boiler is too high, water is needed every day, and then scale will be produced. If it is not cleaned, it will affect the safety of our body. So what are the methods for cleaning boiler scale?

How to remove boiler scale

Boilers should be based on active anti-scaling and anti-corrosion. However, when boiler scaling or corrosion deposits reach a certain level, they should be cleaned and removed in time to avoid potential hazards to the safe operation of the boiler.

The methods of boiler cleaning and descaling are mainly divided into two categories: mechanical descaling and chemical cleaning. Chemical cleaning can be divided into alkaline descaling and acid cleaning. The methods and requirements for boiler descaling are briefly introduced as follows:

1. Mechanical descaling of boiler

Mechanical descaling is mainly carried out using tools such as electric pipe cleaners, flat shovels, wire brushes and hand hammers. This method is relatively simple and low-cost, but it is labor-intensive, has poor descaling effect, and is easy to damage the metal surface. It is only suitable for small boilers with small scaling area and simple structure, which are easy for mechanical tools to contact the scale. In recent years, due to the application of high-pressure water guns specially used for cleaning, mechanical descaling by hydraulic flushing has developed rapidly. The effect of this high-pressure hydraulic descaling is greatly improved compared with the use of primitive mechanical tools, and it is safer and more convenient. but

At present, high-pressure hydraulic descaling is still limited to industrial boilers with simpler structures.

2. Boiler alkaline washing (boiling) descaling

The main function of boiler alkaline boiling is to transform scale and make it loose and fall off. The descaling effect of simple alkaline boiling is poor and often needs to be combined with mechanical descaling. Alkali boiling descaling has a certain effect on scale mainly composed of sulfate and silicate, but it is far less effective than acid washing descaling for carbonate scale. Alkali washing and boiling furnaces are also commonly used for rust removal and degreasing of newly installed boilers, and are sometimes also used for degreasing and cleaning or scale type conversion before pickling.

The amount of alkaline cleaning agent should be determined according to the degree of scaling and dirtiness of the boiler. The general amount used for descaling (amount per ton of water) is: 5-10kg of industrial trisodium phosphate, 3-6kg of sodium carbonate, or 2-4kg of sodium hydroxide. These alkaline cleaning agents should first be prepared into a certain concentration in a solution tank, then pumped into the pot and circulated until uniform.

The method of descaling by alkaline boiling is basically the same as that of boiling a new boiler, except that after the boiling is completed, the inspection holes of the boiler should be opened and mechanical (or high-pressure hydraulic) assisted descaling should be carried out in time to prevent the soft scale from hardening again.

3. Boiler pickling and descaling

Among various descaling methods, pickling has the best descaling effect. However, if the pickling process is inappropriate or improperly controlled, it will affect the descaling effect or corrode the metal, and sometimes even seriously affect the safe operation of the boiler. In order to ensure the safety and quality of boiler pickling, the State Administration of Quality Supervision, Inspection and Quarantine has specially formulated and issued the "Boiler Chemical Cleaning Rules", which stipulates that units engaged in boiler chemical cleaning must obtain qualification approval from provincial and above boiler pressure vessel safety supervision agencies before they can undertake boiler chemical cleaning of the corresponding level. Any unit or individual (including boiler users) without corresponding qualifications may not pickle the boiler without authorization.

Regarding the scale cleaning method of the boiler, it is recommended that you choose a personal professional to do the cleaning, and do not do it on your own. If you clean it last time, it will easily cause the newly softened scale to harden again, which will make the scale impossible to remove. In severe cases, it may cause the boiler to explode, bringing adverse personal harm.