What factors affect the operating load of a circulating fluidized bed boiler?

As domestic environmental protection requirements become increasingly stringent and the conflict between coal combustion and environmental protection becomes more prominent, circulating fluidized bed boilers have become widely used high-efficiency, low-pollution boiler products. The factors that affect the operating load of circulating fluidized bed boilers are the key points for guiding users' daily management operations. Therefore, this article summarizes the factors that affect the operating load of circulating fluidized bed boilers.

The main factors that affect the operating load of circulating fluidized bed boilers are:

(1) Changes in the heating value of coal will affect the bed temperature and thus the load. The higher the heating value, the higher the theoretical combustion temperature. Under the premise of a constant combustion share in the dense phase zone, the bed temperature will be higher, and the steam temperature and pressure will increase accordingly, leading to an increase in the load.

(2) Changes in coal particle size will also affect the load. When the coal particle size increases, the amount of particles escaping from the bed material decreases, and the heat carried to the rear heating surface decreases. As a result, the boiler cannot maintain normal return feed, and the heat carried by the circulating material decreases. This breaks both material and heat balance, resulting in a decrease in boiler load.

(3) The moisture content of coal also affects the load. When the moisture content increases, the heat of vaporization absorbed by steam increases, causing the bed temperature to decrease. However, moisture can also promote the separation of volatile matter and combustion of coke. After subtracting the smoke loss caused by added moisture, the overall trend is a decrease in bed temperature and a decrease in load.

Overall, the factors that affect the operating load of circulating fluidized bed boilers include air volume, wind speed, and material concentration, and their changes are consistent.

As a leading player in the industrial boiler industry, ZOZEN Boiler focuses on the research and development of low-emission circulating fluidized bed boilers, and has organized projects such as "Factors affecting the operating load of circulating fluidized bed boilers". By analyzing the factors that affect the operating load of circulating fluidized bed boilers, the boiler structure has been optimized, resulting in the following advantages:

Circulating fluidized bed belongs to low-temperature combustion, with low nitrogen oxide emissions, achieving emission levels as low as 150mg/Nm3, and even 100mg/Nm3. It can also achieve direct desulfurization during the combustion process, with high desulfurization efficiency.

The fuel has a wide range of uses and high combustion efficiency, reaching more than 89%, making it particularly suitable for low-calorie inferior coal.

The load regulation range of ZOZEN circulating fluidized bed boilers is wide, with low loads capable of reaching around 30% of full load.

The separator structure has been optimized, effectively improving separation efficiency, so that the carbon content of fly ash is no more than 6%, and the carbon content of bottom ash is no more than 2%.

Suitable fluidization velocity has been selected, and measures to prevent wear on each heated surface inside the furnace have been optimized, ensuring long-term operation without wear on the heated surface inside the furnace, and stable exhaust gas temperature. ZOZEN boilers have a minimum annual operating time of 8000 hours and a continuous operating time of no less than 7000 hours.

With a high degree of automation, easy maintenance, and requiring few operating and maintenance personnel.