Regarding the issue of reducing the melting point of coal ash
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Generally, the melting point of coal ash is reduced by adding additives such as limestone to the coal. I would like to ask: at what melting point level of coal ash should additives be added? How is the addition amount calculated? Are there any other additives besides limestone? Can we just add CaO directly?
The operating temperature of the gasification furnace is around 1350°C, which is an appropriate temperature for using refractory bricks; as a result, the wear rate of these bricks is low. Therefore, the ash melting point of the coal fed into the furnace should be 50–80 degrees Celsius lower than the furnace temperature. If the ash melting point is too high, it is necessary to reduce it by adjusting the properties of the coal fed into the furnace
1. When the ash fusion point of coal is below the expected gasifier control temperature by ~100 DegC (a range of 50–150 is acceptable), a flux should be added. 2. Determine the addition ratio based on the ash composition and the melting temperature obtained through calculation or experimentation. 3. There are other flux components available, but limestone is an easily available, cost-effective, and commonly used flux. 4. If the feasibility of addition, economic considerations, environmental pollution, and the controllability of CaO particle size are not taken into account, CaO can be added directly
The two people upstairs are both experts; I’ve learned from them. Now I need to determine through experiments what the appropriate ratio of solubilizing agents should be Is it necessary to simulate the high temperature and high pressure conditions of a gasification furnace? ‘
1. Technically, the proportion of the appropriate fluxing agents is determined by analyzing the ash composition data using specialized software, or by referring to multicomponent ash phase diagrams and calculating based on the composition expected at the desired ash fusion temperature. 2. The suitable ratio is identified through a series of experiments involving different combinations of these fluxing agents. The actual calculation process is quite simple; it can be completed within a few hours or days.
According to empirical formulas, if the ratio of acidic to basic components in the coal ash is less than 5, it is not necessary to add limestone; if the ratio is greater than 5, it should be reduced to 4.8–5, which is more economical. Generally, limestone is added; of course, calcium oxide is a better choice. The calculations are based on the calcium oxide content in the limestone
If the ash fusion point is below 1300 degrees, are additives not necessary?
Additives are additives; they should not be confused with fluxes
Are there any other additives besides limestone? There is calcium hydroxide and iron slag. This post was last edited by 49937790 on 2009-4-16 at 20:45.]
If the ash fusion point is high, it will affect slag discharge from the vaporization furnace as well as the lifespan of the refractory bricks; therefore, it is necessary to keep the ash fusion point within an appropriate range. Usually, a solubilizer is used (with calcium carbonate as its active component, added at a rate of 20% based on the coal content; no solubilizer is needed if the quality of the coal is good). An ash fusion point of around 1280 degrees Celsius is considered optimal