XINLI BOILER

How to deal with the fouling of biomass hot water boiler heating system

16 Jul, 2021

　　The biomass hot water boiler heating system runs for a long time, and a large amount of dirt and water stains will accumulate in the system. If it is not treated, it will affect the boiler operation effect and heating effect. How to deal with these stains and scales?

　　1, soften the water

　　Aiming at the main scale-causing substances such as calcium and magnesium salts in water, an effective method of softening water has been adopted for a long time, that is, nano-ion softening. This method of removing the fouling substances from the water in the boiler without bringing them into the circulation system should be affirmed. If the raw water and make-up water injected into the entire heating system are softened water, the residual hardness under the softened water quality standard is too high, indicating that the scale-causing substances in the water have not been completely cleaned, and the system raw water and make-up water are both softened water. A certain amount of slag will still be produced.

　　This is associated with the magnetic field water treatment device that has appeared in recent years. Its manufacturing basis is that after the water enters the boiler through a certain strength magnetic field, the crystallization process of the scale-causing salts in the water changes, so that new scale is no longer produced, and old scale is removed Become mud. What I want to explain is that even when used in combination, a certain amount of slag will still be generated due to the residual hardness in the system water.

　　2, decontamination device

　　The decontamination device is installed on the inlet pipe of the boiler room and the indoor system to effectively separate the water and slag. But practice shows that its separation effect is limited. In particular, the decontamination device installed at the entrance of the boiler room can be said to have almost no separation effect. Whether it is vertical or horizontal, the design idea is to use a filter screen and a larger volume of sedimentation to achieve the purpose of separating impurities in the water. However, it can be imagined that the metal filter screen is difficult to withstand the impact of the water flow under the water velocity of nearly 2 m/s in the pipeline, and the life of the filter screen is difficult to maintain for more than one month, coupled with corrosion. Moreover, the limited volume of the decontamination device can produce sedimentation. The cyclone decontamination device that has appeared in recent years also has problems. This method is often used for the separation of particles in the gas. Water is different. The sand and clay in the water slag can only be large particles with a large difference in the specific gravity of water. Small particles cannot be separated, so the separation effect of the cyclone decontamination device is also limited. So in practice, is there really no decontamination device with good separation effect? ​​Yes, a large volumetric decontamination tank can play a good separation effect.

　　3. Boiler blowdown

　　Blowdown is very important in steam boilers, and its effect is also very obvious. No matter continuous blowdown or regular blowdown, the excess salt content in the boiler water can be effectively discharged. However, the effect of blowdown in hot water boilers is not very obvious. The difference lies in: First, the steam boiler has only 10T per hour of water intake, while it is 240T in the same capacity hot water boiler. It can be seen that the water flow in the hot water boiler is extremely large, more than 20 times that of the steam boiler of the same capacity. At present, the commonly used sewage discharge method is to stop the circulating pump for 2 hours, wait for the impurities in the water to settle, and then open the sewage valve until clear water is seen. However, the effect of this kind of sewage discharge method is limited, because the sewage pipe provided in the drum and the lower header cannot discharge the distant sediments.

　　4. Clean the stains

　　Practice has proved that a combination of chemical and mechanical methods is the most effective treatment method for cleaning water slag. Some people think that after the heating system is equipped with effective softened water facilities, there is no need to work hard to clean it. This concept is not in line with the actual situation. It should be said that a combination of softened water treatment and cleaning is the most effective and thorough treatment method.

　　(1) Cleaning inside the boiler

　　When the boiler is turned on after the winter operation is over, we can see a large amount of red and black loose slag deposited on the bottom of the drum and in the lower header, and we can also see the flake slag adhering to the drum, water wall, smoke pipe and header. Inner wall. These slags can be cleaned by chemical or mechanical methods. The traditional mechanical device is a furnace washing device; the cleaning effect is better, but due to the limitation of the space in the pot, it cannot be used especially for the pyrotechnic tube boiler. The cleaning method that uses the combination of chemical boiler and high-pressure water rushing machinery is effective, and it can reach the extent that the heated surface of the boiler can see its true color.

　　(2) Cleaning of external network and indoor facilities

　　After the winter operation is over, the water slag in the external network and indoor facilities should also be cleaned. The cleaning of indoor facilities often uses simple manual cleaning. The cleaning of the water slag in the external network can be decontaminated at the entrance of the indoor system when the circulating pump is running. The method to deal with the sewage.