The amount of limestone
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During pressurized coal gasification, limestone is added to lower the ash melting point, but what factors determine the amount of limestone to use? I seek guidance from experts within the field.
I didn’t notice it was posted earlier. The main basis is determined by the CaO, SiO2, and Al2O3 phase diagram; I assume you have this phase diagram available! This post was last edited by victory5460 on 2009-3-7 18:45]
What was said upstairs must refer to its function—waiting for experts to solve it------
Theoretical calculation — Trial firing； Viscosity test.
In accordance with the requirements of the Shel powder gasification process, and taking into account the characteristics of the feed coal, limestone is added to the feed coal in varying proportions, after which its ash fusion point is determined； Experiments have shown that when an appropriate amount of limestone is added to the raw coal, the ash melting point of the raw coal meets the requirements set by the Shel powder gasification process for the ash melting point of the gasifier. When limestone is added during actual production, it facilitates process operation, reduces risks, and ensures the stable operation of the gasification furnace. Generally, for coals with a high ash melting point, a larger amount of limestone needs to be used, with the amount typically controlled between 4% and 10%.
1. Determine the amount of limestone or quartz sand that needs to be added based on the content of acidic and basic oxides in the coal ash composition. 2. After adding limestone or quartz sand, conduct a ash fusion point test to determine the level of the ash fusion point. If the ash fusion point remains high, continue adding more; if it is low, reduce the amount added. After all, what is being added is ash, and it only results in energy consumption.
It depends on the ratio of acidic oxides to basic oxides in the slag, that is, the ratio of SiO2, Al2O3 to CaO and MgO. Since this ratio directly affects the melting point of the slag, the exact amount to add must be determined based on the main components of the raw materials. The amount to be added must be finally determined through processes such as testing, calculation, and trial firing. When the type of coal changes or may cause variations in the chemical composition of the raw materials, the dosage must be determined anew. The useful component of lime is CaO. It also has a desulfurization effect.
The amount of limestone added varies depending on the quality of the coal; if the coal quality meets the production requirements, no limestone needs to be added.
Experience formulas for the ash fusion point can be referred to
It still doesn’t clarify how to calculate it