Formation mechanisms of single and multi-nozzle ash slag

Some information was found, though its accuracy may not be high: 1. Under normal operating conditions, when the furnace temperature is high, more granular glassy ash of about 0.5–10 mm in size is produced, along with some fine ash; additionally, some extremely fine ash and carbon black are carried away by the quenching water； 2. As the furnace temperature decreases, the content of fine ash in the slag gradually increases ； 3. When the furnace temperature drops to a certain limit, approaching the ash melting point, slag blockage begins to occur; before complete blockage takes place, large pieces of slag appear in the ash ； 4. If the operating conditions are changed immediately upon detecting blockage at the slag outlet, and the coal used has high viscosity in its ash and slag, some fibrous glassy slag may be formed during the slag melting process. Analysis of the reasons for the above process: 1. Ash is a general term for heterogeneous mixtures; in fact, when it exists in the furnace as fly ash, there are significant differences among various particles in terms of melting point and other parameters. Some of these particles exist in a solid state, while others are in a liquid state ； 2. At high furnace temperatures, more fly ash particles exist in a liquid state; there is a higher proportion of particles in a liquid or glassy state. When these particles undergo random Brownian motion or inertial mechanical movement, the chance of them sticking together increases, leading to the formation of larger ash particles, similar to how a snowball grows. Such larger ash particles consist both of liquid ash particles that have merged together and of solid ash particles that have adhered to one another, ultimately forming a glassy melt. After being discharged through the slag outlet, these particles take on the form we see as shaped ash particles. 3. According to the principles of Brownian motion, when the furnace temperature is high, not only does the number of liquid fly ash particles increase, but their movement speed also increases slightly. Particles of various shapes collide with the inner wall of the furnace more frequently. The liquid particles first form an adhesive layer on the refractory bricks; they then attract all subsequent liquid or solid particles that collide with them. These particles flow slowly downward along the inner wall of the furnace until they reach the bricks at the slag outlet, where they are discharged like water dripping from a roof edge into the quenching water, thus forming the shaped ash particles that we see. 4. When the furnace temperature is low, and the highly viscous molten slag accumulated in the furnace is not sufficient to block the slag outlet bricks, the opposite process described in points 2 and 3 above occurs: a larger number of fly ash particles fail to reach a molten state and do not adhere to the furnace bricks; instead, they are carried by the process gas into the quenching water for washing, resulting in a large amount of fine ash. 5. Operating under the furnace temperature conditions specified in Article 4 for an extended period carries certain risks. In such cases, the slag with high viscosity adhering to the inner walls of the furnace becomes quite thick. If there are significant fluctuations in the quality of coal, or if the furnace temperature drops further and is no longer sufficient to maintain the fluidity of the slag, a large amount of slag accumulated at the bottom of the cone will be discharged in large chunks. 6. It should also be noted that when operating under condition 4, if the furnace temperature is increased suddenly and rapidly, it can easily cause a large amount of slag adhering to the furnace walls to slide down and block the slag outlet, resulting in the formation of large pieces of slag.