How does the paper slag sludge bubbling bed boiler solve the combustion problem of high-moisture, low-calorific-value fuels using fluidized bed technology?
Publish Time: 2026-02-25
In the field of industrial waste treatment, papermaking sludge and paper scraps are considered typical examples of "difficult-to-burn waste" due to their extremely high moisture content and highly fluctuating calorific value. Traditional stoker furnaces often experience a sudden drop in furnace temperature when processing such materials due to heat absorption from moisture evaporation, leading to unstable combustion or even flameout. This not only results in low heat recovery efficiency but also easily produces large amounts of black smoke and dioxins. The paper slag sludge bubbling bed boiler, with its unique fluidized bed combustion mechanism, creates a high-temperature, uniform, and vibrant "furnace" for these "stubborn" wastes, successfully overcoming the dual challenges of high moisture content and large calorific value fluctuations, achieving efficient and stable energy utilization.1. Huge Thermal Inertia: A "Heat Buffer" to Resist Moisture EvaporationThe core secret of the bubbling bed boiler lies in the thick layer of inert bed material laid at the bottom of its furnace. In operation, these bed materials undergo intense boiling under the pressure of primary air, forming a massive heat storage body. This characteristic constitutes strong "thermal inertia." When wet sludge or paper scraps with high moisture content are fed into the furnace, although the evaporation of moisture instantly absorbs a large amount of heat, the surrounding tons of high-temperature bed material can rapidly release the stored heat energy, forcibly drying the wet material. This "heat-for-moisture" process is extremely rapid, allowing the material to complete dehydration and reach ignition temperature within seconds, avoiding furnace temperature collapse due to excessive local heat absorption and ensuring the continuity of the combustion process.2. Ultimate Mixing Effect: A "Stirrer" for Homogenizing Calorific Value FluctuationsThe calorific value of paper scraps and sludge often fluctuates dramatically depending on their source, sometimes high and sometimes extremely low. In traditional boilers, this fluctuation causes the flame to fluctuate in size, making it difficult to control. However, in a bubbling bed, the intense turbulent motion of the gas and solid phases produces an unparalleled mixing effect. Newly introduced low-calorific-value materials are instantly surrounded, diluted, and heated by a large amount of high-temperature bed material; while high-calorific-value materials are rapidly dispersed to prevent localized overheating and coking. This intense internal circulation and mixing results in an extremely uniform temperature distribution throughout the bed, effectively "shaving off peaks and filling valleys," absorbing fluctuations in the feed calorific value within the furnace, thus ensuring stable boiler outlet steam parameters.3. Long Residence Time and Staged Combustion: Ensuring Complete Combustion of Difficult-to-Burn MaterialsHigh moisture content is often accompanied by difficulties in the escape of volatiles and incomplete combustion of fixed carbon. Bubbling bed boilers, through a special structural design, extend the residence time of materials within the furnace. Large, unburned particles fall back into the bed under gravity or are captured by a separator and returned to the furnace for multiple cycles of combustion. This "repeated tempering" mechanism ensures that even the most difficult-to-burn carbonized nuclei are fully oxidized in a high-temperature, oxygen-rich environment. Meanwhile, the fluidized bed's unique staged air supply technology creates reduction and oxidation zones, promoting the gradual release and combustion of fuel while effectively suppressing the formation of nitrogen oxides, achieving a win-win situation for environmental protection and energy efficiency.4. Highly Adaptable Operational FlexibilityThanks to the above mechanism, the bubbling bed boiler is highly adaptable to various fuels. It can not only handle single high-moisture sludge but also co-incinerate mixed proportions of paper scraps, municipal solid waste, and even biomass. Regardless of changes in feed moisture content, the system can maintain stable operation by automatically adjusting the air-fuel ratio and bed temperature. This flexibility makes it an ideal heat recovery device for paper mills, wastewater treatment plants, and other facilities generating complex waste.In summary, the paper slag sludge bubbling bed boiler, by utilizing the significant thermal inertia of the bed material to resist moisture impact, relying on the intense fluidization and mixing to homogenize calorific value fluctuations, and utilizing a long residence time to ensure burnout rate, perfectly solves the combustion problem of high-moisture, low-calorific-value waste. It not only transforms the environmental burden of the past into valuable green energy, but also demonstrates the outstanding value of fluidized bed combustion technology in the circular economy.
